1 Sumber; http://herbgardens.about.com/od/fertilizer/a/greenmanure.htm PUPUK HIJAUDiabstraksikan oleh:Prof.Dr.Ir.Soemarno, M.S.Jurs tanah fpub maret 2012“Green manure, also called a cover crop, is a great way to add nutrients to the soil. Green manure means planting a crop that is meant to be incorporated into the soil to increase it's fertility. Green manures can be planted in the fall after the herbs have been harvested. You can also plant your green manures as part of your crop rotation during the growing season.”Sumber;
2 PUPUK ORGANIKPupuk organik adalah pupuk yang tersusun dari materi /substansi organik, seperti hasil-hasil pelapukan sisa -sisa tanaman, hewan, dan manusia.Pupuk organik dapat berbentuk padat atau cair yang digunakan untuk memperbaiki sifat fisik, kimia, dan biologi tanah. Pupuk organik mengandung banyak bahan organik daripada kadar haranya.Sumber bahan organik dapat berupa kompos, pupuk hijau, pupuk kandang, sisa panen (jerami, brangkasan, tongkol jagung, bagas tebu, dan sabut kelapa), limbah ternak, limbah industri yang menggunakan bahan pertanian, dan limbah kota (sampah).Sutanto, Rachman. (2002). Pertanian organik: Menuju Pertanian Alternatif dan Berkelanjutan. Jakarta:Kanisius. ISBN X,Suriadikarta, Didi Ardi., Simanungkalit, R.D.M. (2006).Pupuk Organik dan Pupuk Hayati. Jawa Barat:Balai Besar Penelitian dan Pengembangan Sumberdaya Lahan Pertanian. Hal 2. ISBNSumber: ….. Diunduh 11/3/2012
3 Pupuk hijau digunakan dalam: Pupuk hijau adalah pupuk organik yang berasal dari tanaman atau sisa- sisa panen. Bahan tanaman ini dapat dibenamkan pada waktu masih hijau – segar atau setelah dikomposkan.Sumber pupuk hijau adalah sisa-sisa tanaman (sisa panen) atau tanaman yang ditanam secara khusus sebagai penghasil pupuk hijau, seperti sisa–sisa tanaman, kacang-kacangan, dan tanaman paku air (Azolla).Jenis tanaman yang dijadikan sumber pupuk hijau diutamakan dari jenis legume, karena tanaman ini mengandung nitrogen yang relatif tinggi, dibandingkan dengan jenis lainnya.Legume juga relatif mudah terdekomposisi sehingga penyediaan haranya menjadi lebih cepat.Pupuk hijau bermanfaat untuk meningkatkan kandungan bahan organik dan unsur hara di dalam tanah, sehingga terjadi perbaikan sifat fisika, kimia, dan biologi tanah, yang selanjutnya berdampak pada peningkatan produktivitas tanah dan ketahanan tanah terhadap erosi.Pupuk hijau digunakan dalam:Penggunaan tanaman pagar, yaitu dengan mengembangkan sistem pertanaman lorong, dimana tanaman pupuk hijau ditanam sebagai tanaman pagar berseling dengan tanaman utama.Penggunaan tanaman penutup tanah, yaitu dengan mengembangkan tanaman yang ditanam sendiri, pada saat tanah tidak ditanami tanaman utama atau tanaman yang ditanam bersamaan dengan tanaman pokok bila tanaman pokok berupa tanaman tahunan.Parnata, Ayub.S. (2004). Pupuk Organik Cair. Jakarta:PT Agromedia Pustaka. HalSumber: ….. Diunduh 11/3/2012
4 KOMPOSKompos merupakan sisa bahan organik yang berasal dari tanaman, hewan, dan limbah organik yang telah mengalami proses dekomposisi atau fermentasi.Jenis tanaman yang sering digunakan untuk kompos di antaranya jerami, sekam padi, tanaman pisang, gulma, sayuran yang busuk, sisa tanaman jagung, dan sabut kelapa.Bahan dari ternak yang sering digunakan untuk kompos di antaranya kotoran ternak, urine, pakan ternak yang terbuang, dan cairan biogas.Tanaman air yang sering digunakan untuk kompos di antaranya ganggang biru, gulma air, eceng gondok, dan azola.Beberapa manfaat kompos adalah:Memperbaiki struktur tanah.Memperkuat kemantapan agregat pada tanah berpasir.Meningkatkan daya simpan dan daya serap air.Memperbaiki drainase dan pori – pori tanah.Menambah ketersediaan unsur hara.Kompos diaplikasikan dengan cara menyebarkannya di sekeliling tanaman. Kompos yang layak digunakan adalah yang sudah matang, ditandai dengan menurunnya temperatur kompos (di bawah 400 c).Djuarni, Nan, Kristian, Setiawan, Budi Susilo.(2006). Cara Cepat Membuat Kompos. Jakarta:AgroMedia.HalSumber: ….. Diunduh 11/3/2012
5 Tanaman Orok-orok (Crotalaria juncea) cocok sebagai pupuk hijau Tanaman Crotalaria juncea di samping hasil biomasanya tinggi juga mempunyai kandungan N tinggi pula (3,01 % N). Tanaman ini cukup lunak sehingga cocok digunakan utuk sebagai pupuk hijau. Pada waktu yang lalu tanaman selalu ditanam setelah panen selesai.Sebenarnya penggunaan pupuk hijau ini bukan barang baru lagi, namun karena sudah banyak ditinggalkan oleh petani maka pupuk hijau ini terabaikan. Misalnya pada tahun tujuh puluhan, merupakan suatu keharusan pihak pabrik tembakau di Klaten, menanam Crotalaria juncea (orok-orok) pada setiap habis panen tembakau, bertujuan untuk mengembalikan dan memperbaiki kesuburan tanahnya.Setelah tembakau dipanen, ditanam orok-orok, setelah besar maka tanaman orok-orok ini dirobohkan dan dicampur dengan tanah saat pengolahan tanah (pembajakan) yang kemudian digenangi.Pada saat ini keharusan tersebut sukar dipenuhi baik oleh pihak penguysaha maupun petani.Petani merasa keberatan bila sawahnya ditanami legum (orok-orok), karena dianggap tidak produktif, selama penanaman orok-orok (sekitar 1 bulan).Sumber: ….. Diunduh 10/3/2012
6 TANAMAN PUPUK HIJAUPupuk hijau adalah pupuk organik yang berasal dari tanaman atau berupa sisa panen. Bahan tanaman ini dapat dibenamkan pada waktu masih hijau atau setelah dikomposkan.Manfaat pupuk hijau :Meningkatkan kandungan bahan organik dan unsur hara di dalam tanah sehingga terjadi perbaikan sifat fisika, kimia, dan biologi tanah, yang selanjutnya berdampak pada peningkatan produktivitas tanah dan ketahanan tanah terhadap erosi.Sumber pupuk hijau :Sumber pupuk hijau dapat berupa sisa-sisa tanaman (sisa panen) atau tanaman yang ditanam secara khusus sebagai penghasil pupuk hijau atau berasal dari tanaman liar.Jenis tanaman yang dijadikan sumber pupuk hijau diutamakan dari jenis legume, karena tanaman ini mengandung hara yang relatif tinggi(terutama N) dibandingkan dengan jenis tanaman lainnya, tanaman legume juga relatif mudah terdekomposisi sehingga penyediaan haranya menjadi lebih cepat.Sumber: ….. Diunduh 10/3/2012
7 Total hara dalam sisa tanaman kecuali akar PUPUK HIJAU: Sisa tanamanSisa tanaman (sisa panen) merupakan sumber BO yang paling ekonomis karena bahan ini merupakan hasil sampingan dari kegiatan usaha tani, sehingga tidak membutuhkan biaya untuk pengadaannya. Sisa tanaman walaupun kandungan haranya relatif rendah, namun karena total sisa tanaman yang dihasilkan setiap musim panen banyak, maka total unsur hara yang disumbangkan dari setiap musim panen tidak kalah dibandingkan jenis legume.Total hara yang terkandung dalam sisa panen (kecuali akar)TanamanTotal hara dalam sisa tanaman kecuali akarNPKCaMgSKg ha-1Kacang-kacanganK. Tunggak252211786K. Tanah75596016K. Hijau35354189Kedelai15131K. Panjang653323Biji-bijianJagung hibrida455812Jagung local432Padi unggul309310Padi local49Umbi-umbianSingkong61414211Kentang3946Ubi jalar29Sumber: “Pupuk Organik dan Pupuk Hayati” by Litbang, BogorDiunduh 10/3/2012
8 Sumber: “Pupuk Organik dan Pupuk Hayati” by Litbang, Bogor TANAMAN PAGARSalah satu cara menyediakan sumber pupuk hijau adalah dengan mengembangkan sistem pertanaman lorong, dimana tanaman pupuk hijau ditanam sebagai tanaman pagar berseling dengan tanaman utama.Tanaman pagar dapat menghasilkan biomasa secara periodik; pada usim hujan tanaman dapat dipangkas setiap 2 bulan. Aplikasi sistem pertanaman lorong pada lahan miring, dimana legume ditanam searah kontur sangat efektif untuk menekan erosi.Secara umum setiap legume dapat digunakan sebagai tanaman pagar, namun lebih efektif bila tanaman pagar memenuhi sifat-sifat sebagai berikut :Berakar dalam agar tidak menjadi pesaing bagi tanaman semusimPertumbuhan cepat dan setelah pemangkasan cepat bertunas kembaliMampu menghasilkan bahan hijauan dalam jumlah banyak dan terus menerus yang dapat digunakan sebagai pupuk hijauMampu memperbaiki kandungan N dalam tanah dan kandungan hara lainnya.Sumber: “Pupuk Organik dan Pupuk Hayati” by Litbang, BogorDiunduh 10/3/2012
9 Hasil bahan hijauan segar Tanaman legume yang dapat digunakan sebagai tanaman pagar :Produksi pangkasan (data pangkasan tahun kedua dan ketiga) beberapa jenis tanaman pagarJenis tanaman pagarHasil bahan hijauan segarSumberTon ha-1tahun-1Flemingia (Plemingia macrophylla)4,7-26,2Suganda et al., 1991 ; Haryati et al., 1991; Erfandi et al., 1988Glirisidia (Gliricidia sepium)2,9-9,2Suganda et al., 1991Lamtoro gung1,3-2,9Suganda et al., 1991; Kang et al., 1984Lamtoro (Leucaena leucephala)6,1-20Erfandi et al., 1988Thephrosia (Theprosia candida)13,5Haryati et al., 1991Kaliandra (Calliandra callothyrsus)4,3-22,8Suganda et al., 1991; Erfandi et al., 1988Sengon ( Paraserianthes falcataria)1,5-1,6Sumber: “Pupuk Organik dan Pupuk Hayati” by Litbang, BogorDiunduh 10/3/2012
10 Sumber: “Pupuk Organik dan Pupuk Hayati” by Litbang, Bogor TANAMAN PENUTUP TANAHTanaman penutup tanah adalah tanaman yang ditanam sendiri yakni pada saat tanah tidak ditanami tanaman utama atau tanaman yang ditanam bersamaan dengan tanaman pokok bila tanaman pokok berupa tanaman tahunan.Tujuan penanaman tanaman penutup tanah :Melindungi tanah dari daya perusak butir-butir hujanMempertahankan/memperbaiki kesuburan tanahMenyediakan BOMerupakan tindakan rehabilitasi lahan yang murah dan mudah diaplikasikanCover crops are crops planted primarily to manage soil fertility, soil quality, water, weeds, pests, diseases, biodiversity and wildlife in agroecosystems (Lu et al. 2000), ecological systems managed and largely shaped by humans across a range of intensities to produce food, feed, or fiber.Cover crops are of interest in sustainable agriculture as many of them improve the sustainability of agroecosystem attributes and may also indirectly improve qualities of neighboring natural ecosystems. Farmers choose to grow and manage specific cover crop types based on their own needs and goals, influenced by the biological, environmental, social, cultural, and economic factors of the food system within which farmers operate.Lu, Y. C., K. B. Watkins, J. R. Teasdale, and A. A. Abdul-Baki Cover crops in sustainable food production. Food Reviews International 16:Sumber: “Pupuk Organik dan Pupuk Hayati” by Litbang, BogorDiunduh 10/3/2012
11 Sumber: “Pupuk Organik dan Pupuk Hayati” by Litbang, Bogor AZOLLAAzolla merupakan salah satu sumber N alternatif khususnya untuk padi sawah. Azolla merupakan paku air ukuran mini yang bersimbiosis dengan Cyanobacteria pemfiksasi N2.Azolla merupakan satu-satunya genus dari paku air mengapung suku Azollaceae. Terdapat tujuh spesies yang termasuk dalam genus ini.Azolla dikenal mampu bersimbiosis dengan bakteri biru-hijau Anabaena azollae dan mengikat nitrogen langsung dari udara. Potensi ini membuat Azolla digunakan sebagai pupuk hijau baik di lahan sawah maupun lahan kering. Pada kondisi optimal Azolla akan tumbuh baik dengan laju pertumbuhan 35% tiap hari Nilai nutrisi Azolla mengandung kadar protein tinggi antara 24-30%. Kandungan asam amino essensialnya, terutama lisin 0,42% lebih tinggi dibandingkan dengan konsentrat jagung, dedak, dan beras pecah (Arifin, 1996) dalam Akrimin 2002.Tanaman Azolla Sp. memang sudah tidak diragukan lagi konstribusinya dalam memengaruhi peningkatan tanaman padi. Hal ini telah dibuktikan dibeberpa tempat dan beberapa negara. Konstribusi terbesar azolla adalah dengan menjaga hasil panen tetap tinggi. Meskipun penggunaannya sebagai pupuk hijau pada tanaman padi masih dilakukan di China dan Vietnam, dengan adanya peningkatan biaya tenaga kerja, membuatnya kurang diminati.Sejalan dengan perkembangan pupuk hijau, penggunaan azolla lebih banyak dimanfaatkan untuk budidaya perikanan. Dengan adanya mindazbesi yang menggabungkan mina padi dengan azolla, selain menjadikannya sebagai pakan perikanan juga konstribusi dapat digunakan untuk peningkatan produksi padi.Sumber: “Pupuk Organik dan Pupuk Hayati” by Litbang, BogorDiunduh 10/3/2012
12 Rice-duck-azolla system developed by a Japanese farmer Terdapat tujuh jenis Azolla:AsiaAzolla japonica Franch. & Sav. dari JepangA. filiculoides Lam.A. pinnata R. Br. dari Asia Tenggara, juga dari AfrikaAfrikaA. nilotica Dcne. ex Mett.AmerikaA. caroliniana Willd., dari Amerika UtaraA. mexicana Presl., dari MeksikoA. microphylla Kaulf.Rice-duck-azolla system developed by a Japanese farmerSumber: Diunduh 11/3/2012
13 Sumber: “Pupuk Organik dan Pupuk Hayati” by Litbang, Bogor Sesbania rostrataSesbania rostrata merupakan tanaman legume yang potensial sebagai sumber N pada lahan sawah. Tanaman ini dapat tumbuh pada keadaan tergenang, dan dapat membentuk bintil tidak hanya pada akar tetapi juga pada batang.Oleh karena itu tanaman ini mempunyai kemampuan menambat N yang relatif tinggi.Sesbania is a genus of flowering plants in the pea family, Fabaceae and the only genus found in Tribe Sesbanieae. Notable species include the Rattlebox (Sesbania drummondii), Spiny Sesbania (Sesbania bispinosa), and Sesbania sesban, which is used in cooking. Plants of this genus, some of which are aquatic, can be used in alley cropping to increase the soil's nitrogen content.The species of Rhizobia responsible for Nitrogen fixation in Sesbania rostrata is Azorhizobium caulinodans.Sumber: “Pupuk Organik dan Pupuk Hayati” by Litbang, BogorDiunduh 10/3/2012
14 Sesbania grandiflora (L.) Poir. Sesbania grandiflora is a loosely branching tree up to 15 m tall. Its leaves are pinnately compound up to 30 cm long with leaflets in pairs, dimensions x 5-15 mm, oblong to elliptical in shape.Flowers are large, white, yellowish, rose pink or red with a calyx mm long. The standard has dimensions up to 10.5 x 6 cm. Pods are long (20-60 cm) and thin (6-9 mm) with broad sutures containing seeds.It is well adapted to hot, humid environments and does not grow well in the subtropics particularly in areas with cool season minimum temperatures below about 10°C. It is outstanding in its ability to tolerate waterlogging and is ideally suited to seasonally waterlogged or flooded environments. When flooded, they initiate floating adventitious roots and protect their stems, roots and nodules with spongy, aerenchyma tissue. Evans and Macklin (1990) report that S. grandiflora is adapted to rainfall conditions of 2,000-4,000 mm but will grow in areas receiving only 800 mm.In northern Thailand, S. grandiflora was an excellent supplement to dairy cows fed predominantly grass hay. Most reports indicate that the crude protein content of S. grandiflora foliage is generally greater than 20% and often above 25%. Dry matter digestibility of Sesbania species is superior to that of most other tree and shrub legumes. In northeast Thailand, Akkasaeng et al. (1989) found that the in vitro dry matter digestibility of S. grandiflora, S. sesban and S. sesban var. nubica was 66, 75 and 66% respectively, all higher than that of 15 other tree legumes that were tested. van Eys et al. (1986) reported that S. grandiflora contained more crude protein but less fibre than Gliricidia sepium and Leucaena leucocephala while their in vitro dry matter digestibilities were 73.3, 65.2 and 62.2% respectively.Sumber: ….. Diunduh 11/3/2012
15 PUPUK HIJAU(MAPORINA.COM -- Written by beta Monday, 09 August Last Updated ( Wednesday, 02 September 2009 )Pupuk hijau merupakan pupuk yang bahannya berasal dari tanaman atau komponen tanaman yang dibenamkan ke dalam tanah. Jenis tanaman yang banyak digunakan dan memang lebih baik kualitasnya dibanding tanaman lain adalah jenis/familia Leguminoceae. Jenis tanaman tersebut mengandung unsur hara yang lehih baik, terutama unsur Nitrogen dibanding tanaman lain. Jenis tanaman leguminosa mempunyai daya serap hara yang lebih besar dan mempunyai bintil akar. Di dalam metabolismenya bersimbiosis dengan bakteriRhizobium yang dapat mengikat unsur nitrogen dari udara.Keuntungan yang didapat jika menggunakan pupuk hijau :Mampu memperbaiki struktur dan tekstur tanah serta infiltrasi air.Mencegah adanya erosiSangat bermanfaat pada daerah-daerah yang sulit dijangkau untuk suplai pupuk anorganik.Manfaat lain spesies pupuk hijau dapat dijadikan sebagai pakan ternak, kayu bakar bahkan sebagai makanan manusia.Syarat-syarat tanaman pupuk hijau yang akan di pilih adalah sebagai berikut :Menghasilkan banyak biomas.Dapat menekan dan mengendalikan gulma.Prosentase produksi daun lebih besar dari pada bagian yang berkayu.Mempunyai kemampuan kemampuan mengikat nitrogennya tinggi dan melepaskan nutrisi pada tanah.Berumur pendek, cepat tumbuh, mempunyai kemampuan megakumulasi hara.Sumber: ….. Diunduh 10/3/2012.
16 PUPUK HIJAU(MAPORINA.COM -- Written by beta Monday, 09 August Last Updated ( Wednesday, 02 September 2009 )Tanaman yang berfungsi sebagai pupuk hijau, selain tanaman kacang-kacangan/polong-polongan, jenis rumput-rumputan ( rumput gajah ), dan Azolla juga baik sebagai bahan pupuk hijau.Tanaman pupuk hijau yang cocok ditanam pada lahan pematang tanaman padi maupun lahan-lahan yang kosong, sedangkan Azolla adalah merupakan jenis tanaman pakuan air yang hidup di perairan.Seperti halnya tanaman leguminosae, Azolla mampu menambat N2 udara karena berasosiasi dengan sianobakteri (Anabaena azollae) yang hidup di dalam rongga daun Azolla.Menurut Khan (1983), kemampuan Azolla mengikat N2 dari udara berkisar antara 400 – 500 kg N/ha/tahun. Azolla berkembang Sangat cepat dan dapat menghasilkan biomassa sebanyak ton/ha dengan C/N ratio 12 – 18, sehingga dalam waktu satu minggu Azolla telah terdekomposisi dengan sempurna. Sumber: ….. Diunduh 10/3/2012.
17 KEUNTUNGAN PUPUK HIJAU Green manuring can bring a number of advantages to the grower:Adding organic matter to the soilIncreasing biological activityImproving soil structureReduction of erosionIncreasing the supply of nutrients available to plants (particularly by adding nitrogen to the system by fixation)Reducing leaching lossesSuppressing weedsReducing pest and disease problemsProviding supplementary animal forageDrying and warming the soilGreen manure crops are also useful for weed control, erosion prevention, and reduction of insect pests and diseases. The deep rooting properties of many green manure crops make them efficient at suppressing weeds. Green manure crops often provide habitat for many native pollinators as well as predatory beneficial insects, which allow for a reduction in the input of insecticides where cover crops are planted. Some green manures are also successful at suppressing plant diseases, especially Verticillium wilt in potato. Incorporation of green manures into a farming system can drastically reduce, if not eliminate, the need for additional products such as supplemental fertilizers and pesticides.Vasilakoglou, Ioannis, Dhima, Kico, Anastassopoulos, Elias, Lithourgidis, Anastasios, Gougoulias, Nikolaos, and Chouliaras, Nikolaos Oregano green manure for weed suppression in sustainable cotton and corn fields. Weed Biology and Management 11:38-48.Larkin, Robert P., Honeycutt, Wayne, and Olanya Modesto, O Management of Verticillium Wilt of Potato with Disease-Suppressive Green Manures and as Affected by Previous Cropping History. Plant Dis. 95:Sumber: Diunduh 10/3/2012
18 KERUGIAN PUPUK HIJAU Green manure crops A number of disadvantages can also be identified:Direct costs of seed and extra cultivationsLost opportunities for cash croppingExtra work at busy times of the yearExacerbated pest and disease problems (due to the ‘green bridge’ effect)Potential for the green manures to become weeds in their own rightA wide range of plant species can be used as green manures. Different ones bring different benefits and the final choice is influenced by many considerations which will be examined later on in this review. If the most is to be made from green manure crops it is important that they are carefully integrated into the crop rotation and proper attention paid to their husbandry.Green manure cropsAnother important contribution of green manure to an agricultural field is the nitrogen fixing ability and consequent nitrogen accumulation in the soil, particularly of those leguminous crops used. Depending on the species of cover crop grown, the amount of nitrogen released into the soil lies between 40 and 200 pounds per acre. With green manure use, the amount of nitrogen that is available to the succeeding crop is usually in the range of 40-60% of the total amount of nitrogen that is contained within the green manure crop.Sullivan, Preston Overview of Cover Crops and Green Manures: Fundamentals of Sustainable Agriculture.Sumber: Diunduh 10/3/2012
19 THE EFFECTS OF GREEN MANURES Minimising nitrate leaching Large quantities of nitrate can be lost from soil which is left bare overwinter. This is because, unlike other nutrient ions, nitrate is not strongly attracted to soil particles. Any that is in solution in the autumn will be washed away as water moves down through the soil with the onset of heavy winter rains.This is bad for the environment (nitrate can contribute to the formation of algal blooms in watercourses) and for human health (when contaminated water is drunk). As a result EU regulations have been introduced to control farming practices likely to result in large nitrate losses.This has resulted in the establishment of Nitrate Sensitive Areas (Tunney, 1992). For farmers, leaching also represents the loss of a valuable resource – this is particularly serious for organic farmers because it is much harder for them to replace the lost nitrogen.It is widely recognised that one of the best ways of preventing nitrate leaching is to maintain a vigorously growing crop over the winter period (MAFF, 1998).Tunney, H (1992). The EC Nitrate Directive. Aspects of Applied Biology 30: 5-10.MAFF (1998). Code of Good Agricultural Practice for the Protection of Water (Available form DEFRA).Sumber: Diunduh 10/3/2012
20 Project Leader: Peter Knight An example of overwinter nitrate concentrations below bare soil plots and plots on which grazing rye was growing. This trial was set up directly after the incorporation of a grass/clover ley.Winter green manures can be very effective crops for ‘mopping up’ excess nitrate in the soil in the autumn and this effect was studied at HDRA. One example is shown in figure , nitrate concentrations were measured at 60cm depth and the wave of nitrate passing down the profile can be clearly seen.GREEN MANURES. A review conducted by HDRA as part of HDC Project FV 299: An investigation into the adoption of green manures in both organic and conventional rotations to aid nitrogen management and maintain soil structure.Project Leader: Peter KnightVegetable Consultancy Services Ltd. The Finches, Cake Street Old Buckenham . Attleborough, Norfolk NR17 1RU
21 KETERSEDIAAN N BAGI TANAMAN BERIKUTNYA Of all the nutrient elements, nitrogen is the most labile in soil and the one most likely to be affected by green manures. This is because it exists in so many different forms that are inter-converted by a range of biological processes – some of these forms are prone to losses (by leaching or gaseous emissions of ammonia, nitrogen or nitrous oxides).For some crops (eg cauliflowers) it is particularly important that sufficient nitrogen is available at certain growth stages to ensure that the plants produce yields of a marketable quality and correct management of green manures can be used to manipulate its availability.Large amounts of nitrogen are added to the soil by a successful green manure (eg an overwintered crop of vetch may accumulate up to 200kg N/ha by early May). How soon this becomes available to plants (a process of conversion of complex molecules to ammonium and nitrate ions known as mineralisation) will depend on many factors (Jarvis et al , 1996).Jarvis, SC, Stockdale, EA, Shepherd MA & Powlson DS (1996). Nitrogen mineralization in temperate agricultural soils; processes and measurements. Advances in Agronomy 57:
22 MINERALISASI PUPUK HIJAU Mineralisation proceeds fastest when the soil is warm and moist. The quantity of nitrogen released is also dependant on the total amount actually added to the soil and the chemical composition of the incorporated material. It is not just the C;N ratio which is important. The carbon can be in different forms (eg lignin is more resistant to decomposition than cellulose) and some plants contain chemicals (eg polyphenols) which can inhibit microbial action.Rahn et al (1999) compared the chemical characteristics of various agricultural residues with their patterns of decomposition.Incorporation of cover crops into the soil is immediately followed by an increase in abundance of soil microorganisms that aid in the decomposition of this fresh material. The degradation of plant material allows the nutrients held within the green manure to be released and made available to the succeeding crop. This additional decomposition also allows for the re-incorporation of nutrients that are found in the soil on a particular farm such as nitrogen (N), potassium (K), phosphorus (P), calcium (Ca), magnesium (Mg), and sulfur (S). Microbial activity in the soil also leads to the formation of mycelium and viscous materials which benefit the health of the soil by increasing its soil structure (i.e. by aggregation).Soil that is well- aggregated has increased aeration and water infiltration rates, and is more easily turned or tilled than non- aggregated soil. Further aeration of the soil results from the ability of the root systems of many green manure crops to efficiently penetrate compact soils. The amount of humus found in the soil also increases with higher rates of decomposition, which is beneficial for the growth of the crop succeeding the green manure crop.Rahn, C.R., Bending, G., Lillywhite, R., Turner M. (1999). Chemical characterisation of vegetable and arable crop residue materials: a comparison of methods.. Journal of the Science of Food and Agriculture 79 p
23 PUPUK HIJAU – KESUBURAN TANAH Results from an experiment where overwintered vetch was incorporated at three different dates in the spring. Vetch is a plant which has a high nitrogen content throughout its life (3-4% of its dry weight). And is consequently readily mineralisable. It puts on a lot of growth in late April and the highest levels of mineral nitrogen resulted from the latest incorporation date in May.In some cases a ‘priming effect’ may be seen ie the addition of green manures can stimulate the mineralisation of organic matter already in the soil. See Rayns and Lennartsson (1995) for more information.An example of patterns of soil mineral nitrogen (0-30cm) after incorporation of an overwintered vetch crop at three different dates in the springRayns, FW & Lennartsson, M (1995) The nitrogen dynamics of winter green manures. In HF Cook and HC Lee (eds) Soil Management in Sustainable Agriculture, Proceedings 3rd International Conference on Sustainable Agriculture, Wye College Wye College Press, Ashford, pp Sumber: ….. Diunduh 10/3/2012
24 PUPUK HIJAU – KETERSEDIAAN HARA The most extensive study was carried out by Jensen et al. (2005) where the effectiveness of five types of catch crop (Italian ryegrass, lupin, chicory, rumex and kidney vetch) were compared on a soil deficient in P and K. In this study, nutrient uptakes of catch crops were all low with 2-4 kg P / ha and 15-30kg K /ha taken up annually. This low uptake was attributed to low biomass production (1-2 t/ha) of the catch crops on the infertile soils. Moreover, after incorporation, the catch crops had no effect on the P uptake in the subsequent barley crop.The conclusions that could be drawn from this study were that under these conditions of poor soil fertility, catch crops made very little contribution to making P and K more available to subsequent crops. However, this work does not answer the question as to whether they have a role to prevent losses on more fertile soils.The root systems of some varieties of green manure grow deep in the soil and bring up nutrient resources unavailable to shallower-rooted crops.Jensen, L., Pedersen, A., Magid. J. & Nielsen, N. (2005) Catch crops have little effect on P and K availability of depleted soils. Newsletter from Danish Research Centre for Organic Farming • June 2005 • No. 2.
25 PUPUK HIJAU – KETERSEDIAAN FOSFAT There is work that has focussed on the ability of some plants, particularly lupins and buckwheat to increasephosphate mobility in the soil. Lupins grown in P deficient soil were found to extrude protons and organic acids such as citric acid, increasing the mobility and uptake of P (Shen et al., 2005; Neuman et al., 2000).P deficiency also stimulated the formation of cluster roots which are more active in P uptake (Sas et al., 2001).Buckwheat has also been shown to extrude organic acids and under conditions of low P availability on a calcareous soil, P uptake was ten fold higher than in wheat (Zhu et al., 2002).Phosphorus uptake by green manure crops in 2004Sas, L., Rengel, Z. & Tang, C. (2001) Excess cation uptake, and extrusion of protons and organic acid anions by Lupinus albus under phosphorus deficiency Plant Science 160:Shen, J. Li, H., Neumann, G. & Zhang, F. (2005) Excess cation uptake, and extrusion of protons and organic acid anions by Lupinus albus under phosphorus deficiency. Plant Science 168:Zhu, Y,G., He, Y,Q, Smith, S.E. & Smith, F.A. (2002) Buckwheat (Fagopyrum esculentum Moench) has high capacity to take up phosphorus (P) from a calcium (Ca)-bound source. Plant and Soil 239: 1–8.
26 PUPUK HUJAI – UNSUR HARA LAIN There is also work to suggest that micronutrients such as sulphur may be leached out of sandy soils and eventually become deficient in low input systems (Eriksen & Askegaard, 2000).One study (Eriksen & Thorup- Kristensen, 2002) found that cruciferous crops such as winter rape or fodder radish were particularly effective at preventing sulphur being leached into lower soil profiles. Moreover this increased availability was realised as an increase in sulphur content in the subsequent barley crop.Other green manures such as chicory have also been reported to accumulate large amounts of micronutrients including sulphur, boron, manganese, molybdenum, and zinc (Rumball, 1986).Sulfur mineralization in two soils amended with organic manures, crop residues, and green manuresKotha Sammi Reddy, Muneshwar Singh, Anand Swarup, Annangi Subba Rao, Kamlesh Narain Singh. Journal of Plant Nutrition and Soil Science. Vol 165, Issue 2, p. 167–171, April 2002.The mineralization of sulfur (S) was investigated in a Vertisol and an Inceptisol amended with organic manures, green manures, and crop residues. Field-moist soils amended with 10 g kg—1 of organic materials were mixed with glass beads, placed in pyrex leaching tubes, leached with 0.01 M CaCl2 to remove the mineral S and incubated at 30 °C. The leachates were collected every fortnight for 16 weeks and analyzed for SO4-S. The amount of S mineralized in control and in manure-amended soils was highest in the first week and decreased steadily thereafter. The total S mineralized in amended soils varied considerably depending on the type of organic materials incorporated and soil used. The cumulative amounts of S mineralized in amended soils ranged from 6.98 mg S (kg soil)—1 in Inceptisol amended with wheat straw to mg S (kg soil)—1 in Vertisol amended with farmyard manure (FYM). Expressed as a percentage of the S added to soils, the S mineralized was higher in FYM treated soils (63.5 to 67.3 %) as compared to poultry manure amended soils (60.5 to 62.3 %). Similarly the percentage of S mineralization from subabul (Leucaena leucocephala) loppings was higher (53.6 to 55.5 %) than that from gliricidia (Gliricidia sepium) loppings (50.3 to 51.1 %). Regression analysis clearly indicated the dependence of S mineralization on the C : S ratio of the organic materials added to soil. The addition of organic amendments resulted in net immobilization of S when the C : S ratio was above 290:1 in Vertisol and 349:1 in Inceptisol. The mineralizable S pool (So) and first-order rate constant (k) varied considerably among the different types of organic materials added and soil. The So values of FYM treated soils were higher than in subabul, gliricidia, and poultry manure treated soils.Eriksen, J & Askegaard, M (2000) Sulphate leaching in an organic crop rotation on sandy soil in Denmark. Agriculture, Ecosystems and Environment 78:Rumball, W. (1986) ‘Grasslands Puna’ chicory (Cicorium intybusL.) New Zealand Journal of Experimental Agriculture 14:
27 PUPUK HIJAU – AGREGASI TANAH Green manures can improve soil structure in a number of ways. The extensive fine roots of some, such as rye,enmesh the soil, helping to stabilise aggregates and increasing pore size thus improving seedbed structure (Breland, 1995).Some species also produce deep tap roots which help break up compacted soil. A series of pot experiments (Lofkvist et al., 2005) identified lucerne roots as being particularly effective at penetrating hard layers, with chicory, lupin, red clover as having intermediate ability and barley the poorest. A key function of green manures is the addition of organic matter to the soil.They do this whilst still growing, producing root exudates which provide food for micro organisms, which in turn produce polysaccharide gums, which “glue” soil aggregates together (Reid & Goss, 1981).They may also provide a bridge between mycorrhizal crops in order to maintain a high population of soil mycorrhiza, which help maintain soil structure, again by enmeshing soil aggregates. Brassicas and lupins, however, are non mycorrhizal and will break that bridge.Breland, T. (1995) Green manuring with clover and ryegrass catch crops undersown in spring wheat : effects on soil structure Soil Use and Management 11:Löfkist, J., Whalley, W.R. & Clark, L.J. (2005) A rapid screening method for good root-penetration ability: Comparison of species with very different root morphology Acta Agriculturae Scandinavica 55:Reid, J.B. & Goss, M.J. (1981) Effect of living roots of different plant species on the aggregate stability of two arable soils European Journal of Soil Science 32:521.
28 PUPUK HIJAU - BOTOnce incorporated, the green manure provides a pool of fresh organic matter and there are numerous examples where using green manures increases soil organic matter in comparison to treatments where inorganic fertilisers alone are applied (e.g. Shepherd et al., 2002).This organic matter provides food to soil micro organisms, encouraging an increase in numbers and activity (N’Dayegamuye & Tran, 2001).Managing Crop Residue with Green Manure, Urea, and Tillage in a Rice–Wheat RotationMilkha S. Aulakh, T. S. Khera, John W. Doran, and Kevin F. Bronson. Soil Sci. Soc. Am. J. 65:820–827 (2001).Shepherd, M.A., Harrison, R. & Webb, J.(2002) Managing soil organic matter – implications for soil structure on organic farms. Soil Use and Management 18:284N’Dayegamiye, A & Tran, T.S. (2001) Effects of green manures on soil organic matter and wheat yields and N nutrition Canadian Journal of Soil Science. 81: 371–382
29 PUPUK HIJAU - EROSI TANAH The more succulent a green manure is the more rapidly it will decay once incorporated and the less effect it will have on long term soil organic matter. Older woody green manures with a higher C:N ratio break down more slowly and breakdown is reported to decrease to a very slow rate at C:N ratios above 16:1 (Enwezor, 1975).Legumes which have a low C:N ratio, break down rapidly so have little effect on long term soil organic matter but give a larger short term boost to soil structure as they have a large short term effect on soil micro organisms.Green manures can also play a part in reducing soil erosion both by wind and rain (Cransberg & McFarlane, 1994). Wind erosion is reduced as the green manure increases surface roughness reducing the wind speed close to the soil. The root system also has a binding effect on the soil. The green manure also reduces run off substantially, at ground covers of greater than 75%, reducing erosion by rain.Enwezor, W.O. (1976) The mineralization of nitrogen and phosphorus in organic materials of varying C:N and C:P ratios Plant and Soil 44:Cransberg, L. & McFarlane, D.J. (1994) Can perennial pastures provide the basis for a sustainable farming system in southern Australia? New Zealand Journal of Agricultural Research 37:
30 PUPUK HIJAU - PENGENDALIAN GULMA One of the major benefits of green manures is the ability to suppress weeds. This can occur by a number of different mechanisms that were reviewed by Liebman & Davis (2000). The various mechanisms are considered here. Firstly green manures can reduce weed infestation by disrupting cycles. Weeds often become adapted to a particular niche cycle of planting and cultivations if similar types of crops are grown continuously (Blackshaw, 1994).Growing a green manure adds diversity to the rotation and reduces the opportunities for weeds to become adapted to a niche cropping cycle. Competition for light, water and nutrients is another important way in which green manures reduce weed infestation. Rapidly growing crops with large ground cover, such as mustard, are the most effective at doing this and McLenaghen et al (1996) found that weed suppression was directly correlated with the ground cover of the green manure. Management practices associated with growing a green manure can also suppress weeds.The lack of soil disturbance during the long growing period of a ley can also reduce seed germination (Roberts & Feast, 1973).Blackshaw, R.E. (1994) Rotation affects downy brome (Bromus tectorum) in winter wheat (Triticum aestivum). Weed Technology 8:Mclenaghen, R.D., Cameron, K.C., Lampkin, N.H., Daly, M.L. & Deo, B. (1996) Nitrate leaching from ploughed pasture and the effectiveness of winter catch crops in reducing leaching losses. New Zealand Journal of Agricultural Research 39:Roberts, H.A. & Feast P.M.(1973) Emergence and longevity of seeds of annual weeds in cultivated and undisturbed soil. Journal of Applied Ecology 10:
31 GREEN MANURE = PUPUK HIJAU. In agriculture, a green manure is a type of cover crop grown primarily to add nutrients and organic matter to the soil. Typically, a green manure crop is grown for a specific period of time , and then ploughed under and incorporated into the soil while green or shortly after flowering. Green manure crops are commonly associated with organic agriculture, and are considered essential for annual cropping systems that wish to be sustainable. Traditionally, the practice of green manuring can be traced back to the fallow cycle of crop rotation, which was used to allow soils to recover.Sumber: ..….. Diunduh 4/3/2012Pupuk hijau adalah pupuk organik yang berasal dari tanaman atau berupa sisa panen. Bahan tanaman ini dapat dibenamkan pada waktu masih hijau atau setelah dikomposkan.Sumber: ..….. Diunduh 4/3/2012
32 Sumber: http://en.wikipedia.org/wiki/Green_manure ….. Diunduh 4/3/2012 FUNGSI PUPUK HIJAUGreen manure crops may include legumes such as cowpeas, soybeans, annual sweet clover, vetch, sesbania, and velvet beans, as well as non-leguminous crops such as sudangrass, millet, sorghum, and buckwheat (Sullivan, Preston Overview of Cover Crops and Green Manures: Fundamentals of Sustainable Agriculture.Legumes are often used as green manure crops for their nitrogen fixing abilities, while non-leguminous crops are used primarily for weed suppression and addition of biomass to the soil.Pupuk hijau biasanya mempunyai multi-fungsi, termasuk perbaikan kualitas tanah dan perlindungan tanah:Leguminous green manures such as clover and vetch contain nitrogen-fixing symbiotic bacteria in root nodules that fix atmospheric nitrogen in a form that plants can use.Green manures increase the percentage of organic matter (biomass) in the soil, thereby improving water retention, aeration, and other soil characteristics.The root systems of some varieties of green manure grow deep in the soil and bring up nutrient resources unavailable to shallower-rooted crops.Common cover crop functions of weed suppression and prevention of soil erosion and compaction are often also taken into account when selecting and using green manures.Some green manure crops, when allowed to flower, provide forage for pollinating insects.Sumber: ….. Diunduh 4/3/2012
33 Sumber: http://en.wikipedia.org/wiki/Green_manure ….. Diunduh 4/3/2012 MANFAAT PUPUK HIJAUGreen manure crops are also useful for weed control, erosion prevention, and reduction of insect pests and diseases. The deep rooting properties of many green manure crops make them efficient at suppressing weeds(Vasilakoglou, Ioannis, Dhima, Kico, Anastassopoulos, Elias, Lithourgidis, Anastasios, Gougoulias, Nikolaos, and Chouliaras, Nikolaos Oregano green manure for weed suppression in sustainable cotton and corn fields. Weed Biology and Management 11:38-48.).Green manure crops often provide habitat for many native pollinators as well as predatory beneficial insects, which allow for a reduction in the input of insecticides where cover crops are planted. Some green manures are also successful at suppressing plant diseases, especially Verticillium wilt in potato(Larkin, Robert P., Honeycutt, Wayne, and Olanya Modesto, O Management of Verticillium Wilt of Potato with Disease-Suppressive Green Manures and as Affected by Previous Cropping History. Plant Dis. 95: ).Incorporation of green manures into a farming system can drastically reduce, if not eliminate, the need for additional products such as supplemental fertilizers and pesticides.Sumber: ….. Diunduh 4/3/2012
34 Sumber: http://en.wikipedia.org/wiki/Cover_crops ….. Diunduh 4/3/2012 COVER CROP =TANAMAN PENUTUP TANAHCover crops are crops planted primarily to manage soil fertility, soil quality, water, weeds, pests, diseases, biodiversity and wildlife in agroecosystems (Lu et al. 2000), ecological systems managed and largely shaped by humans across a range of intensities to produce food, feed, or fiber.Cover crops are of interest in sustainable agriculture as many of them improve the sustainability of agroecosystem attributes and may also indirectly improve qualities of neighboring natural ecosystems. Farmers choose to grow and manage specific cover crop types based on their own needs and goals, influenced by the biological, environmental, social, cultural, and economic factors of the food system within which farmers operate (Snapp et al. 2005).Lu, Y. C., K. B. Watkins, J. R. Teasdale, and A. A. Abdul-Baki Cover crops in sustainable food production. Food Reviews International 16:Snapp, S. S., S. M. Swinton, R. Labarta, D. Mutch, J. R. Black, R. Leep, J. Nyiraneza, and K. O'Neil Evaluating cover crops for benefits, costs and performance within cropping system niches. Agron. J. 97:1-11.Sumber: ….. Diunduh 4/3/2012
35 PENGELOLAAN KUALITAS TANAH TANAMAN PENUTUP TANAHPENGELOLAAN KUALITAS TANAHCover crops can also improve soil quality by increasing soil organic matter levels through the input of cover crop biomass over time. Increased soil organic matter enhances soil structure, as well as the water and nutrient holding and buffering capacity of soil (Patrick et al. 1957). It can also lead to increased soil carbon sequestration, which has been promoted as a strategy to help offset the rise in atmospheric carbon dioxide levels (Kuo et al. 1997, Sainju et al. 2002, Lal 2003).Although cover crops can perform multiple functions in an agroecosystem simultaneously, they are often grown for the sole purpose of preventing soil erosion. Soil erosion is a process that can irreparably reduce the productive capacity of an agroecosystem. Dense cover crop stands physically slow down the velocity of rainfall before it contacts the soil surface, preventing soil splashing and erosive surface runoff (Romkens et al. 1990). Additionally, vast cover crop root networks help anchor the soil in place and increase soil porosity, creating suitable habitat networks for soil macrofauna (Tomlin et al. 1995).Soil quality is managed to produce optimum circumstances for crops to flourish. The principal factors of soil quality are soil salination, pH, microorganism balance and the prevention of soil contamination.Kuo, S., U. M. Sainju, and E. J. Jellum Winter cover crop effects on soil organic carbon and carbohydrate in soil. Soil Science Society of America Journal 61:Lal, R Offsetting global CO2 emissions by restoration of degraded soils and intensification of world agriculture and forestry. Land Degradation & Development 14:Patrick, W. H., C. B. Haddon, and J. A. Hendrix The effects of longtime use of winter cover crops on certain physical properties of commerce loam. Soil Science Society of America 21:Romkens, M. J. M., S. N. Prasad, and F. D. Whisler Surface sealing and infiltration. Pages in M. G. Anderson and T. P. Butt, editors. Process studies in hillslope hydrology. John Wiley and Sons, Ltd. Sainju, U. M., B. P. Singh, and W. F.Sainju, U. M., B. P. Singh, and W. F. Whitehead Long-term effects of tillage, cover crops, and nitrogen fertilization on organic carbon and nitrogen concentrations in sandy loam soils in Georgia, USA. Soil & Tillage Research 63:Tomlin, A. D., M. J. Shipitalo, W. M. Edwards, and R. Protz Earthworms and their influence on soil structure and infiltration. Pages in P. F. Hendrix, editor. Earthworm Ecology and Biogeography in North America. Lewis Pub., Boca Raton, FL.Sumber: ….. Diunduh 4/3/2012
36 PENGELOLAAN KESUBURAN TANAH TANAMAN PENUTUP TANAHPENGELOLAAN KESUBURAN TANAHOne of the primary uses of cover crops is to increase soil fertility. These types of cover crops are referred to as "green manure." They are used to manage a range of soil macronutrients and micronutrients. Of the various nutrients, the impact that cover crops have on nitrogen management has received the most attention from researchers and farmers, because nitrogen is often the most limiting nutrient in crop production.Often, green manure crops are grown for a specific period, and then plowed under before reaching full maturity in order to improve soil fertility and quality.Green manure crops are commonly leguminous, meaning they are part of the Fabaceae (pea) family. This family is unique in that all of the species in it set pods, such as bean, lentil, lupins and alfalfa. Leguminous cover crops are typically high in nitrogen and can often provide the required quantity of nitrogen for crop production. In conventional farming, this nitrogen is typically applied in chemical fertilizer form. This quality of cover crops is called fertilizer replacement value (Thiessen-Martens et al. 2005).Thiessen-Martens, J. R., M. H. Entz, and J. W. Hoeppner Legume cover crops with winter cereals in southern Manitoba: Fertilizer replacement values for oat. Canadian Journal of Plant Science 85:Sumber: ….. Diunduh 4/3/2012
37 PENGELOLAAN LENGAS TANAH TANAMAN PENUTUP TANAHPENGELOLAAN LENGAS TANAHBy reducing soil erosion, cover crops often also reduce both the rate and quantity of water that drains off the field, which would normally pose environmental risks to waterways and ecosystems downstream (Dabney et al. 2001). Cover crop biomass acts as a physical barrier between rainfall and the soil surface, allowing raindrops to steadily trickle down through the soil profile. Also, as stated above, cover crop root growth results in the formation of soil pores, which in addition to enhancing soil macrofauna habitat provides pathways for water to filter through the soil profile rather than draining off the field as surface flow. With increased water infiltration, the potential for soil water storage and the recharging of aquifers can be improved (Joyce et al. 2002).Just before cover crops are killed (by such practices including mowing, tilling, discing, rolling, or herbicide application) they contain a large amount of moisture. When the cover crop is incorporated into the soil, or left on the soil surface, it often increases soil moisture. In agroecosystems where water for crop production is in short supply, cover crops can be used as a mulch to conserve water by shading and cooling the soil surface. This reduces evaporation of soil moisture. In other situations farmers try to dry the soil out as quickly as possible going into the planting season. Here prolonged soil moisture conservation can be problematic.Dabney, S. M., J. A. Delgado, and D. W. Reeves Using winter cover crops to improve soil quality and water quality. Communications in Soil Science and Plant Analysis 32:Joyce, B. A., W. W. Wallender, J. P. Mitchell, L. M. Huyck, S. R. Temple, P. N. Brostrom, and T. C. Hsiao Infiltration and soil water storage under winter cover cropping in California's Sacramento Valley. Transactions of the Asae 45:Sumber: ….. Diunduh 4/3/2012
38 Sumber: http://en.wikipedia.org/wiki/Cover_crops ….. Diunduh 4/3/2012 TANAMAN PENUTUP TANAHPENGELOLAAN GULMAThick cover crop stands often compete well with weeds during the cover crop growth period, and can prevent most germinated weed seeds from completing their life cycle and reproducing. If the cover crop is left on the soil surface rather than incorporated into the soil as a green manure after its growth is terminated, it can form a nearly impenetrable mat. This drastically reduces light transmittance to weed seeds, which in many cases reduces weed seed germination rates (Teasdale 1993). Furthermore, even when weed seeds germinate, they often run out of stored energy for growth before building the necessary structural capacity to break through the cover crop mulch layer. This is often termed the cover crop smother effect (Kobayashi et al. 2003).Some cover crops suppress weeds both during growth and after death (Blackshaw et al. 2001). During growth these cover crops compete vigorously with weeds for available space, light, and nutrients, and after death they smother the next flush of weeds by forming a mulch layer on the soil surface.For example, Blackshaw et al. (2001) found that when using Melilotus officinalis (yellow sweetclover) as a cover crop in an improved fallow system (where a fallow period is intentionally improved by any number of different management practices, including the planting of cover crops), weed biomass only constituted between 1-12% of total standing biomass at the end of the cover crop growing season. Furthermore, after cover crop termination, the yellow sweetclover residues suppressed weeds to levels 75-97% lower than in fallow (no yellow sweetclover) systems .Blackshaw, R. E., J. R. Moyer, R. C. Doram, and A. L. Boswell Yellow sweetclover, green manure, and its residues effectively suppress weeds during fallow. Weed Science 49:Kobayashi, Y., M. Ito, and K. Suwanarak Evaluation of smothering effect of four legume covers on Pennisetum polystachion ssp. setosum (Swartz) Brunken. Weed Biology and Management 3:Teasdale, J. R Interaction of light, soil moisture, and temperature with weed suppression by hairy vetch residue. Weed sci 41:46-51.Sumber: ….. Diunduh 4/3/2012
39 Sumber: http://en.wikipedia.org/wiki/Cover_crops….. Diunduh 4/3/2012 TANAMAN PENUTUP TANAHPENGELOLAAN PENYAKITIn the same way that allelopathic properties of cover crops can suppress weeds, they can also break disease cycles and reduce populations of bacterial and fungal diseases (Everts 2002), and parasitic nematodes (Potter et al. 1998, Vargas-Ayala et al. 2000).Species in the brassicaceae family, such as mustards, have been widely shown to suppress fungal disease populations through the release of naturally occurring toxic chemicals during the degradation of glucosinolade compounds in their plant cell tissues (Lazzeri and Manici 2001).Everts, K. L Reduced fungicide applications and host resistance for managing three diseases in pumpkin grown on a no-till cover crop. Plant dis 86:Lazzeri, L., and L. M. Manici Allelopathic effect of glucosinolate-containing plant green manure on Pythium sp and total fungal population in soil. Hortscience 36:Potter, M. J., K. Davies, and A. J. Rathjen Suppressive impact of glucosinolates in Brassica vegetative tissues on root lesion nematode Pratylenchus neglectus. Journal of Chemical Ecology 24:67-80.Vargas-Ayala, R., R. Rodriguez-Kabana, G. Morgan-Jones, J. A. McInroy, and J. W. Kloepper Shifts in soil microflora induced by velvetbean (Mucuna deeringiana) in cropping systems to control root-knot nematodes. Biological Control 17:11-22.Sumber: Diunduh 4/3/2012
40 Sumber: http://en.wikipedia.org/wiki/Cover_crops ….. Diunduh 4/3/2012 TANAMAN PENUTUP TANAHPENGELOLAAN HAMASome cover crops are used as so-called "trap crops", to attract pests away from the crop of value and toward what the pest sees as a more favorable habitat (Shelton and Badenes-Perez 2006).Trap crop areas can be established within crops, within farms, or within landscapes. In many cases the trap crop is grown during the same season as the food crop being produced. The limited area occupied by these trap crops can be treated with a pesticide once pests are drawn to the trap in large enough numbers to reduce the pest populations. In some organic systems, farmers drive over the trap crop with a large vacuum-based implement to physically pull the pests off the plants and out of the field (Kuepper and Thomas 2002). This system has been recommended for use to help control the lygus bugs in organic strawberry production (Zalom et al. 2001).Other cover crops are used to attract natural predators of pests by providing elements of their habitat. This is a form of biological control known as habitat augmentation, but achieved with the use of cover crops (Bugg and Waddington 1994). Findings on the relationship between cover crop presence and predator/pest population dynamics have been mixed, pointing toward the need for detailed information on specific cover crop types and management practices to best complement a given integrated pest management strategy. For example, the predator mite Euseius tularensis (Congdon) is known to help control the pest citrus thrips in Central California citrus orchards.Bugg, R. L., and C. Waddington Using Cover Crops to Manage Arthropod Pests of Orchards - a Review. Agriculture Ecosystems & Environment 50:11-28.Kuepper, G., and R. Thomas "Bug vacuums" for organic crop protection. ATTRA, Fayetteville, AR.Shelton, A. M., and E. Badenes-Perez Concepts and applications of trap cropping in pest management. Annual Review of Entomology 51:Zalom, F. G., P. A. Phillips, N. C. Toscano, and S. Udayagiri UC Pest Management Guidelines: Strawberry: Lygus Bug. University of California Department of Agriculture and Natural Resources, Berkeley, CA.Sumber: ….. Diunduh 4/3/2012
41 PUPUK HIJAUGreen manures, often known as cover crops, are plants which are grown to improve the structure and nutrient content of the soil. They are a cheap alternative to artificial fertilisers and can be used to complement animal manures.Growing a green manure is not the same as simply growing a legume crop, such as beans, in a rotation. Green manures are usually dug into the soil when the plants are still young, before they produce any crop and often before they flower. They are grown for their green leafy material which is high in nutrients and protects the soil.If food is in very short supply it may be better to grow a legume from which a bean crop can be harvested and then dig the plant remains into the soil.These plant remains will not break down into the soil so quickly and will not be as good for the soil as younger plants but they will still add some nutrients to the soil for the next crop.Sumber: ….. Diunduh 4/3/2012
42 An example of a rotation where a legume is used as a green manure ROTASI PUPUK HIJAUAn example of a rotation where a legume is used as a green manureSumber: ….. Diunduh 4/3/2012
43 GREEN MANURES : UNDERSOWING Undersowing involves growing a green manure at the same time as a crop, among the crop plants. Sometimes they are sown with the crop or slighlty later when the crops are already growing. This reduces competition between the green manure and the crop.For example, undersowing is sometimes used with maize crops where a green manure is sown under the young maize plants.The green manure seeds are broadcast sown when the second weeding of the maize is carried out. In this way when the maize is harvested the green manure is already established and ready to grow quickly. This method means that no extra time is spent preparing the land and sowing the green manure.Sumber: ….. Diunduh 4/3/2012
44 PUPUK HIJAU BERSAMA TANAMAN POKOK A green manure (for example a bean) sown beneath maizeTanaman pokokPupuk hijauSumber: ….. Diunduh 4/3/2012
45 PUPUK HIJAU JANGKA PANJANG Green manures can be grown for more than one season and used in the following ways:• Long term green manures restore poor soil. Using them over a long time has a greater benefit on soil fertility and structure of poor soil.• Long term green manures can be used when new land is being prepared for use, especially to help control difficult perennial weeds.• Long term green manures are used where land is to have a long fallow period. They can be sown at the beginning of the fallow of bush-fallow systems. They help to quickly build up the fertility of the soil and reduce the length of time before the land can be used to grow crops again.• Long term green manures provide green material which can be cut and carried to other fields. Green material can be harvested from perennial species such as alfalfa (Medicago sativa), for digging in, mulching, composting or feeding to livestock.Sumber: ….. Diunduh 4/3/2012
46 PUPUK HIJAU UNTUK MULSA Green manure plants can be cut and left on the soil surface as a mulch.Mulching releases nutrients slowly but has some advantages:• Mulching helps to prevent weed growth• Mulching protects the soil from erosion• Mulching keeps the soil moist by reducing evaporation.Sumber: ….. Diunduh 4/3/2012
47 PUPUK HIJAU DALAM AGROFORESTRY Green manures in agroforestry Agroforestry is the practice of growing trees and/or shrubs together, with crops and/or animals. The trees/shrubs act as long term green manures and the leaves can be used for digging in or as a mulch.The regular pruning of agroforestry trees such as Leucaena (Leucaena leucocephala), Mother of cocoa (Gliricidia sepium) and Calliandra (Calliandra calothyrsus) during the crop growing period provides large amounts of green material for digging into the soil and reduces competition with the main crop.The material can also be used as a mulch.It is spread on the top soil, usually between crop rows or before a crop has been planted.As well as improving the soil in the ways described above, trees and shrubs also provide food, fodder, fuelwood, erosion control and other benefits.Sumber: ….. Diunduh 4/3/2012
48 The benefits of nutrient cycling and erosion control in agroforestry SISTEM AGROFORESTRYThe benefits of nutrient cycling and erosion control in agroforestrySumber: ….. Diunduh 4/3/2012
49 PEMBENAMAN PUPUK HIJAU Digging in green manures Before a crop is sown the green manure is dug back into the soil. Here it decomposes and the nutrients held inside green manure plants are released.• The plants take a short time, usually about two weeks, to rot down into the soil before the next crop is sown.• Green manures should not be ploughed in as this buries the plants and the nutrients too deep. They should be turned in just under the soil surface.• Digging is easier if the plants have been chopped into small pieces before digging. This also helps prevent the problem of regrowth if this should occur.• If digging-in is difficult the plants can be dug in roughly, left for a few days and dug over again.Sumber: ….. Diunduh 4/3/2012
50 PEMILIHAN PUPUK HJIJAU When choosing which green manure plant to use, you should consider thefollowing points:A green manure must suit the local climate, and the soil that it is to be sown in. This will help to keep the green manure healthy and to keep pests and diseases to a minimum.Fast growing and leafy green manures are often preferred as they provide more nutrients when dug in.Green manures should not be closely related to the following crop as they could attract pests and diseases which may affect the following crop.It is important to know whether seed is easily available and affordable.The length of time that land is free and how long the green manure will take to grow.Plants which can be grown as a green manure include legumes and non-legumes. Legumes have nodules on their roots which contain bacteria. These bacteria take nitrogen from the air. This is known as ‘nitrogen-fixation’. Plants use this to grow, but this extra nitrogen is also made available to future crops when the legumes are dug into the soil.The ability of legumes to ‘fix’ nitrogen makes them very good green manures. However they do have limitations and non-legumes can sometimes be more suitable.Sumber: ….. Diunduh 4/3/2012
51 PUPUK HIJAU LEGUMEThere are many types of plants that can be used as green manures.Legumes are particularly beneficial because they increase the amount of nitrogen in the soil.In the tropics they are also more common than non-legumes.Here are some examples of legumes for which detailed information can be obtained from HDRA.Sumber: ….. Diunduh 4/3/2012
52 PUPUK HIJAU PADA TANAMAN TEBU Trash composting: when trash is kept on the fields as mulch, evaporation of moisture is greatly reduced. The soil is protected from the direct impact of the elements and hence soil life develops extremely well. Soil quality and structure improve. Finally as the trash decomposes, nutrients are taken up by the roots again to make new growth.Sumber: ….. Diunduh 10/3/2012
53 PUPUK HIJAU PADA TANAMAN TEBU Green manuring: green manure is, according to Suresh, a source of nitrogen and other elements compensating for the high carbon content of the trash.He uses a combination of many plants for his green manure mix. He also believes that with this combination the ill effects of the monocropping pattern without rotation, as is the case in his sugar cane fields, can be overcome. Furthermore, his green manure mix consists of plants and crops that were grown before when dry farming was practised, it re-establishes equilibrium in the soil, which these plants help to maintain.The green manure mix is generally made up of cowpea, mustard, amaranth, coriander, horse gram sesame, sunnhemp and chickpea, amongst others. Initially Suresh used to prepare a green manure mix which was inter-sown between the lines of cane using a bullock drawn implement. Nowadays the green manure seeds are mixed with clay and manure and formed into balls (large pellets). These balls are then just dropped in the trash at regular intervals between the canes. The green manure plants are cut once or twice at 30 to 40 day intervals.Sumber: ….. Diunduh 10/3/2012
54 PUPUK HIJAU PADA TANAMAN TEBU Soil conditioning:to enhance the decomposition of the sugar cane trash, Suresh applies a conditioner on the fields at the time of irrigation in the form of slurry. Consisting of 250 grams of wet yeast and 500 grams of jaggery, mixed with 10 kg of cow dung and a little water, this enhances the proliferation of fungi, hastening the breakdown of the fibres of the trash.In fact after application of this slurry an enormous development of fungi, sometimes forming a white cake, can clearly be seen. This has, according to Suresh, a great influence on the water-retention capacity of the soil and makes it possible for him to reduce irrigation to only once in 25 days.With the application of trash, green manure and the conditioner, the soil has become very fertile, healthy and sweet.The proof of this is his canes which grow fast, are vigorous and sturdy and problem-free.Sumber: ….. Diunduh 10/3/2012
55 PUPUK HIJAU PADA TANAMAN TEBU DAMPAK LAINNYASuresh's canes mature in 8 sometimes 8.5 months compared to 11 or 12 months in the conventional system.Sugar recovery is much better in his canes than in chemically grown ones. Though he sells his canes together with the other farmers (making it difficult to give exact figures), Suresh has been told that the recovery of his canes is 11.5 percent whereas for the other farmers it is a maximum 11 percent.His canes are very healthy and no problems of smut or grassy shoot, the main problems of the area, have occurred in his fields for the last five years. Neither chemical nor botanical sprays are needed.Suresh obtains an average yield of 100 tonnes per hectare. His neighbours who follow the conventional methods obtain on an average 110 ton per hectare, but his costs are far less.Suresh claims that with his method, the amount of irrigation water needed is even less than that consumed by sprinkler irrigation.As minimum tillage is practised and there is no fallow or replanting of sugar cane, labour requirements have been reduced.Suresh's focus on natural biological cycles as the main input to the farm has caused an impressive increase in soil biodiversity. This biodiversity is now working for him, maintaining yields.The use of traditional dry farming crops in his green manure mix functions as a gene pool for rapidly disappearing species.Sumber: ….. Diunduh 10/3/2012
56 AGRONOMY OF GREEN MANURE CROPS Sumber: Diunduh 10/3/2012
57 SITHAGATHI (Sesbania speciosa) Season: Can be grown in all seasons, March – April is best for sowing Soil: Grown in all types of soil conditions Seed rate: 30 – 40 kg/ha for green manure Seed purpose 15 kg/ha Seed treatment: Mix seeds with specific rhizobium 5 pkts /ha Spacing: Broadcasted, for seed purpose adopt 45 x 20 cm Irrigation: Once in 15 – 20 days Harvest: Incorporate the green mater DAS & for seed collect the seeds 130 DAS Yield: Green biomass – 15-18t/ha, Seed – kg/ha
58 DHAINCHA (Sesbania aculeata) Season: Grown in all seasons when sufficient moisture is available Sowing during March – April is best for seed production Soil: Grown in all soil conditions Seed rate: Green manure: 50 kg/ha Seed purpose 20 kg/haSeed treatment Mix seeds with specific rhizobium 5 pkts /ha Spacing: Broadcasted, For seed purpose adopt 45 x 20 cm Irrigation: Once in 15 – 20 days Harvest: Incorporate the green matter within DAS & collect seeds from 100 DASYieldGreen biomass – 25 t/ha Seed – kg/ha
59 MANILA AGATHI - Sesbania rostrata Season Grown in all seasons Sowing during February-May yields more biomass. March – May sowing is best for seed productionSoilBlack & red soils are suitable, Saline alkaline soils are not suitable Seed rate: 40 kg/ha for green manure, Seed purpose 7-8 kg/ha Seed treatment: Seeds to be scarified with concentrated H2SO4 (100 ml/kg) by soaking for 10 minutes then wash thoroughly (10-15 times). Mix seeds with specific rhizobium 5 pkts /ha Spacing: Broadcasted For seed purpose adopt 45 x 20 cmIrrigation: Once in 15 – 20 days Nipping: For seed purpose it should be done 60 DAS to increase branching and seed yield Harvest: Incorporate the green mater within DAS & Seeds can be collected from 100 DAS (3-4 harvest) Yield: Green biomass – 20 t/ha Seed – kg/ha
60 SUNNHEMP (Crotalaria juncea) Season: Grown in all seasons, Sowing during March – April is best for seeds production Soil: Loamy soils are suitable Seed rate: kg/ha for green manure Seed purpose: 20 kg/ha Seed treatment: Mix seeds with specific rhizobium 5 pkts /ha Spacing: Broadcasted or 30x10cm For seed purpose adopt 45 x 20 cm Irrigation: Once in 30 days Harvest: Incorporate the green mater within DAS For seed purpose: Collect the seeds from 150 DAS Yield: Green biomass – t/ha, Seed – 400 kg/ha
61 WILD INDIGO (Tephrosia purpurea) Season: Grown in all seasons Sowing during March – April is best for seeds production. Soil: Can be grown in all soils, sandy soils are suitable. Seed rate: kg/ha for green manure Seed purpose 10 kg/ha. Seed treatment: Soak the seeds in concentrated sulphuric acid (100 ml /kg seed) for 30 minutes and then thoroughly wash the seeds in water for times and shade dry. Spacing: Broadcasted For seed purpose: Adopt 30 x 10 cm. Irrigation: Once in 30 days Harvest: Incorporate within 60 DAS & for seed collect from 150 DAS. Yield Green biomass – 6-7 t/ha Seed – kg/ha
62 PILLIPESARA (Phaseolus trilobus) Dual purpose crop yielding good fodder and green manure Herbaceous creeper grows into a short dense cover crop if sown thick. Does not produce a bulky yield, it is capable of being cut twice or thrice before being ploughed into the field Season: Grown in all seasons March – April month is best for seeds production Soil: Rice fallow clay soils are suitable Seed rate: kg/ha for green manure Seed purpose 10 kg/ha Spacing: Broadcasted For seed purpose adopt 30 x 10 cm Irrigation: Once in days Harvest: Incorporate the green mater within 60 DAS & for seed collect the seeds from 150 DAS Yield: Green biomass – 6-7 t/ha Seed – kg/ha Source:
63 FIKSASI NITROGEN LEGUME Due to their nitrogen fixation potential, legumes represent an alternative for supplying nutrients, substituting or complementing mineral fertilization in cropping systems involving green manuring. The objective of this study was to evaluate the N balance in a soil-plant system involving green manures sunn hemp (Crotalaria juncea L.) and velvet bean (Mucuna aterrima Piper & Tracy), both labeled with 15N. They were incorporated into two soils of contrasting textural classes: a clayey Eutrudox and a sandy-clayey Paleudalf, both cultivated with corn.The research was carried out in a greenhouse, using pots containing 6 kg of air dried soil, to which the equivalent to 13 Mg ha-1 dry matter of above-ground mass plus 2.7 or 2.2 Mg ha-1 of velvet bean and sunn hemp roots were incorporated, respectively, with 15N labeling of either shoots or roots.One hundred days after emergence of the corn, the velvet bean residues provided higher accumulation of N in the soil, higher absorption by corn plants and accumulation in the shoot.The green manure decomposition was more intense in the medium-textured Paleudalf. The highest nitrogen losses were also observed in this soil.Sci. agric. (Piracicaba, Braz.) vol.66 no.3 Piracicaba May\June 2009SOILS AND PLANT NUTRITIONNitrogen supply to corn from sunn hemp and velvet bean green manuresEdmilson José Ambrosano; Paulo Cesar Ocheuze Trivelin; Heitor Cantarella; Gláucia Maria Bovi Ambrosano; Eliana Aparecida Schammass; Takashi Muraoka; Nivaldo Guirado; Fabrício Rossi.Sumber: Diunduh 10/3/2012
64 SERAPAN N TANAMANThe accumulation of N in corn roots increased with time. These results indicate that there are also losses due to shedding, root exudation and root death (Allison, 1966), and that losses of N from the above ground part are much more expressive, that the above ground part N can be translocated to the roots reflecting on the accumulation of N in roots . There was an increase in dry matter mass of the corn above ground part until 100 DAE. At this stage, the plants were starting to flower.
65 PRODUKSI BIOMASA TANAMAN There was an increase in dry matter mass of the corn above ground part until 100 DAE. At this stage, the plants were starting to flower. The only difference observed was at the first date (20 DAE), when the control plants grew more than those with green manure (Table 6).
66 SERAPAN N TANAMANThe occurrence of the nitrogen decline accumulation in the above ground part of the corn plant, at the end of the cycle (Table 5) was also reported by other authors (Flores, 1986; Villas Bôas, 1990), as well as for sugarcane (Ng Kee Kwong & Deville, 1994). The probable cause of this could be the fact that some N of the above ground part was redistributed to the root system, as well as lost to the atmosphere by volatilization through the leaves via transpiratory strem in either immature or senescing leaves. According to Farquhar et al. (1979), an NH3 gaseous losses occurs through the leaves due to an increase in proteolysis during senescence.
67 The soil mineral N (nitrate and ammonium) contents were higher until 40 DAE in the velvet bean treatment followed by the sunn hemp and the control (Table 8). Beyond 60 DAE the values were lower than 1.6 mg kg-1, without differences among treatments (Table 8). For the sunn hemp there were time differences, with a decline in the green manure contribution to the soil mineral N. However, this did not happen with the velvet bean treatment, indicating that, besides the largest contribution of the green manure plants to the soil mineral N, there also was a greater mineralization, since the test-plant continued absorbing the mineral N from the soil.Sumber: ….. Diunduh 10/3/2012
68 PUPUK HIJAU SUMBER NBecause of their potential for N2 biological fixation, legumes are an alternative source of nitrogen to crops, and can even replace or supplement mineral fertilization.A greenhouse experiment was carried out to evaluate temporal patterns of velvet bean (Mucuna aterrima) green manure release of nitrogen to rice plants, and to study the fate of nitrogen from velvet bean in rice cultivation. The isotopic dilution methodology was used.Treatments consisted of a control and 10 incubation periods of soil fertilized with 15N-labeled velvet bean (0, 20, 40, 60, 90, 120, 150, 180, 210, and 240 days). The plant material was previously chopped, sifted (10 mm mesh sieve) and oven-dried (65ºC). Incubation of the plant material (2.2 g kg-1 soil) was initiated by the longest period, in order to synchronize the planting of the test crop, rice (Oryza sativa), at time zero for all treatments.Green manure incorporation promoted increases in rice dry matter yield and nitrogen uptake. These variables showed maximum values at incubation periods of 38 and 169 days, respectively. Green manure nitrogen utilization by rice plants was highest at an incubation period corresponding to 151 days. More than 60% of the green manure nitrogen remained in the soil after rice cultivation. The highest green manure nitrogen recovery from the soil-plant system occurred at an incubation period equivalent to 77 days.Sci. agric. (Piracicaba, Braz.) vol.61 no.2 Piracicaba Mar./Apr. 2004Fate of nitrogen (15N) from velvet bean in the soil-plant systemWalkyria Bueno Scivittaro; Takashi Muraoka; Antonio Enedi Boaretto; Paulo César Ocheuze Trivelin.Sumber: ….. Diunduh 10/3/2012
69 MINERALISASI N PUPUK HIJAU The nitrogen applied to the soil in the form of green manures may take different pathways: part is absorbed by the plants, part is lost from the soil-plant system, and the rest remains in the soil, as non-decomposed residues, or is immobilized by microorganisms, and gradually converted into stable forms.The magnitude of these transformations varies depending on environmental conditions (Azam et al., 1985) and quality of the plant residues (Smith & Sharpley, 1993).AZAM, F.; MALIK, K.A.; SAJJAD, M.I. Transformations in soil and availability to plants of 15N applied as inorganic fertilizer and legume residues. Plant and Soil, v.86, p.3-13, 1985.SMITH, S.J.; SHARPLEY, A.N. Nitrogen availability from surface-applied and soil-incorporated crop residues. Agronomy Journal, v.85, p , 1993. Understanding nitrogen (N) mineralization patterns of green manure legume residues is crucialin the synchronization of N release from plant residue and uptake by plants. A laboratoryincubation experiment was conducted over a 16-week period to determine N mineralization ofthree green manure legumes [(Mucuna (Mucuna pruriens), Lablab (Lablab purpureus cv. Rongai) and Sunhemp (Crotalaria juncea)] in three soils with varying clay contents (62, 20 and 12% clay) from South Africa. The amount of N mineralized from the residues was determined at 2, 4, 8 and 16 weeks from the onset of incubation. Nitrogen release pattern of the three legume residues followed a similar pattern in all the three soils, with sunhemp treated soil having the highest amount of mineral N after 16 weeks of incubation in all the three soils, followed by lablab and then mucuna. The amount of mineral N ranged from 121 to170, 96 to 134 and 92 to 108 mg kg-1 in the sunhemp, lablab and mucuna treated soils, respectively. The cumulative amounts of N from the legume residues mineralized recovered as mineral N in soil after 16 weeks of incubation ranged from % ( mg kg-1), 30-68% ( mg kg-1) and 26-60% ( mg kg-1) of the initial added N contained in the residues in the soils with 62, 20 and 12% clay contents, respectively.Less than 50% of the initial added N was mineralized in the high clay content soil. Mineralization rate constant, k, was significantly linearly related to the residue N content, net mineralized N, C/N ratio and Lignin/N ratio. Results from this study indicate that all the three legumes can contribute significant amounts of N for uptake by plants, with sunhemp tending to release N at a faster rate, followed by lablab and then mucuna. High clay content in soil slowed down N mineralization.Nitrogen mineralization of green manure legume residues in different soil typesOdhiambo, Jude J.O, University of VendaThe Proceedings of the International Plant Nutrition Colloquium XVI, Department of Plant. Sciences, UC Davis, UC DavisN mineralized from legume residues recovered as mineral N in (a) 12% claysoil (b) 20% clay soil and (c) 62% clay soil.
70 RECOVERY N PUPUK HIJAUUnder field conditions, most of the N that comes from plant residues remains in the soil, mainly in the organic form.In general, the recovery of N from green manures by the subsequent crop is low, ranging from 5% to 30% (Müller & Sundman, 1988; Harris et al., 1994).MÜLLER, M.M.; SUNDMAN, V. The fate of nitrogen (15N) released from different plant materials during decomposition under field conditions. Plant and Soil, v.105, p , 1988. HARRIS, G.H.; HESTERMAN, O.B.; PAUL, E.A.; PETERS, S.E.; JANKE, R.R. Fate of legume and fertilizer nitrogen-15 in a long term cropping systems experiment. Agronomy Journal, v.86, p , 1994. Nitrogen mineralization of green manure legume residues in different soil typesOdhiambo, Jude J.O, University of VendaThe Proceedings of the International Plant Nutrition Colloquium XVI, Department of Plant. Sciences, UC Davis, UC DavisN mineralized from legume residues recovered as mineral N in (a) 12% claysoil (b) 20% clay soil and (c) 62% clay soil.
71 PUPUK HIJAU DAN HASIL PADI Dry matter yield and nitrogen utilized by rice plants, in the control treatment, and Dunnett test significance, contrasting the effects of treatments involving velvet bean incorporation relative to the controlVelvet bean incorporation increased dry matter yield of rice plants relatively to the control, except for the 240-day incubation period.Sumber: Diunduh 10/3/2012
72 PUPUK HIJAU DAN HASIL PADI Dry matter yielded by rice plants, relative to differentsoil incubation periods with velvet bean green manure.An effect of incubation period on dry matter yield of the aerial part and whole rice plants (aerial part + roots) was observed. However, no influence on the dry matter yielded by the roots alone was observed (Figure 1). For both variables, the quadratic model provided the best fitting of the results. From the equation relative to the aerial part + roots, the maximum dry matter yield of rice plants was determined, corresponding to an incubation period of 38 days.
73 PUPUK HIJAU DAN NITROGEN Amount of nitrogen from the green manure recovered (ANR) and lost (ANL) from the soil-plant system, relative to different soil incubation periods with velvet bean green manure.Nitrogen from the green manure recovered and lost from the soil-plant systemThe amounts of nitrogen from the green manure recovered and lost from the soil-plant system were influenced by incubation period, and the results were fitted by quadratic models. The maximum N recovery from the velvet bean occurred at the 80-day incubation period, corresponding to 86% of the nitrogen contained in the green manure.Sumber: ….. Diunduh 10/3/2012
74 Soil Biology and Biochemistry, v.13, p.251-256, 1981. DEKOMPOSISI PUPUK HIJAUDALAM TANAHThe values determined for N recovery from thegreen manure are intermediate, relative to the intervals described in the literature, which vary from 66% to 102% (Azam et al., 1985; Ladd et al., 1981).AZAM, F.; MALIK, K.A.; SAJJAD, M.I.Transformations in soil and availability to plants of 15N applied as inorganic fertilizer and legume residues.Plant and Soil, v.86, p.3-13, 1985.LADD, J.N.; OADES, J.M.; AMATO, M.Distribution and recovery of nitrogen from legume residues decomposing in soils sown to wheat in field.Soil Biology and Biochemistry, v.13, p , 1981.Sumber: ….. Diunduh 10/3/2012
75 L. Talgre, E. Lauringson, H. Roostalu, A. Astover. Agronomy Research 7(1), , 2009The effects of green manures on yields and yield quality of spring wheatL. Talgre, E. Lauringson, H. Roostalu, A. Astover.A field experiment was conducted in the period of 2004–2006 to investigate the effect of green manure treatments on the yield and yield quality of spring wheat. In the experiment, different green manure crops were compared for amounts of N, C and organic matter applied into soil and their effect on the yield and yield quality of succeeding cereals.The amount of organic matter applied into soil was dependent on the cultivated crop. The highest amount of organic matter was applied with hybrid lucerne, the lowest, with unfertilised oats. With sowings of red clover, lucerne and hybrid lucerne, 4.91–7.70 Mg C ha-1 and 341.9–379.1 kg N ha-1 were added to soil with green material and roots.The yield of spring wheat on unfertilised soil was 2.12 Mg ha-1, but the treatment with hybrid lucerne as a preceding crop gave an extra yield of 1.45 Mg ha-1. Green manure crops did not have a unilateral effect on the quality of spring wheat. Grain yield grew with the increased norm of mineral nitrogen, but there was no significant improvement in quality indicators.Sumber: ….. Diunduh 10/3/2012
76 PUPUK HIJAU - KETERSEDIAAN HARA Cultivation of leguminous green manure crops is the main possibility for soil enrichment with nutrients, especially with nitrogen.Nitrogen binding by leguminous crops reaches its peak in the period ofblooming, and starts decreasing in the period of seed formation (Leinonen, 2000).The productivity of cereals depends on soil properties, meteorological factors, fertilisation, and especially humus content in soil.Ploughed-in green material enriches soil with organic matter, which as a result of microbiological processes releases nutrients for plants.Leinonen, P Lannoitus luomuviljan viljelyksessä. Luomuviljan tuotanto. Tietotuottamaan 86. Helsinki: Maaseutukeskusten Liitto, 40–50. (in Finlandian)
77 BIOMASA SISA PANENThe largest amount of organic matter is left in the soil with the residues of perennial grasses, less with annual grasses, winter cereals, maize, spring cereals, grain legumes and others (Maiksteniene & Arlauskiene, 2004).According to Viil & Võsa (2005), the amount of nitrogen left in soil in the sowing year of white sweet clover and red clover is 247 kg/ha and 160 kg/ha respectively.Sumber: Maiksteniene S. and Arlauskiene A Effect of preceding crops and green manure on the fertility of clay loam soil. Agronomy Research 2 (1), 87–97.P. ja Võsa, T Liblikõielised haljasväetised. EMVI infoleht lk. (in Estonian)
78 EFEK POSITIF PUPUK HIJAU The residues and ploughed-in green material of perennial grasses, as preceding crops, have a positive effect on the formation of productivity elements of cereal crops not only in the first year but also in the second year, which determines the productivity of the cereal link (Skuodien & Nekrošiene, 2007).The results suggest that red clover is the optimum species for use as green manure (Stopes et al., 1996).Skuodiene, R. and Nekrošiene, R Impact of perennial legumes and timothy as green manure on productivity of Secale cereale L. and x Triticosecale Wittm and on occurrence of cereal diseases. Agronomy Research 5 (1), 59–71.Stopes, C., Millington S. and Woodward L Dry matter and nitrogen accumulation by three leguminous green manure species and the yield of a following wheat crop in an organic production system. Agriculture, Ecosystems & Environment. Vol. 57, Issues 2-3,189–196
79 BIOMASA TANAMAN PUPUK HIJAU Quantities of dry matter (Mg ha-1) applied into soil in Vertical bars denote confidence limits (CL 0.05 – level of statistical significance).Agronomy Research 7(1), , 2009The effects of green manures on yields and yield quality of spring wheatL. Talgre, E. Lauringson, H. Roostalu, A. Astover.
80 Nayyar, V.K. and Chhibba, I.M. 2000. Effect of Green Manuring on Micronutrient Availability in Rice-Wheat Cropping System of Northwest India.Page in Long-term Soil Fertility Experiments in Rice-Wheat Cropping Systems (Abrol, I.P., Bronson, K. F., Duxbury, J. M. and Gupta, R. K. eds.). Rice-Wheat Consortium Paper Series 6. New Delhi, India: Rice-Wheat Consortium for the Indo-Gangetic Plains.Rice cultivation in highly permeable coarsetexturedsoils in recent years has given rise to anumber of micronutrient deficiency problems.While paddy yields in such soils are poor due toiron (Fe) deficiency, wheat yields are lowbecause of manganese (Mn) deficiency.In view of the observations that Sesbania green manuring can help improve rice yield, the present investigation was undertaken to study the effects of regular incorporation of Sesbania green manure for sustaining yields of rice-wheat system.Regular incorporation of Sesbania green manure before rice transplanting resulted in significant improvement in paddy yield over that in the non-green manured plots.The increase in micronutrients, particularly Fe and Mn, and of organic carbon seemed to be responsible for increased rice yields in these soils. No residual effect of green manuring was observed in wheat.
81 PUPUK HIJAU BIOMASA SESBANIA Preliminary studies carried out by the authors have revealed that incorporation of Sesbania (Sesbania aculeata Poir.) green manure (GM) before transplanting rice can ameliorate Fe deficiency by promoting reduced conditions besides improving other physicochemical characteristics of the soil (Nayyar and Takkar 1989).Nayyar, V.K., and Takkar, P.N Combating iron deficiency in rice grown in sandy soils of Punjab. Pages in International Symposium on Managing Sandy Soils. Vol. 1. Jodhpur, India: Central Arid Zone Research Institute.
82 PUPUK HIJAU – KETERSEDIAAN HARA MIKRO Regular cultivation of rice on such soils causes manganese (Mn) deficiency in the following crops of wheat/berseem (Trifolium alexandrinum L.) because of excessive leaching of soluble Mn resulting from submergence during rice cultivation and oxidation of limited amount of available Mn in surface soil to its higher oxides during wheat/berseem cultivation (Takkar and Nayyar 1981).To overcome that loss, foliar application of Mn was suggested (Nayyar et al. 1990).It is, however, expected that regular incorporation of Sesbania GM before transplanting rice may improve availability of not only Fe but also other micronutrient cations.Takkar, P.N., and Nayyar, V.K Preliminary field observations of manganese deficiency in wheat and berseem. Fertiliser News 26:22.23.Nayyar, V.K., Takkar, P.N., Bansal, R.L., Singh, S.P., Kaur, N.P., and Sadana, U.S Micronutrients in soils and crops of Punjab. Research Bulletin. Ludhiana, India: Department of Soils, Punjab Agricultural University. 146+xiv pp.
83 PUPUK HIJAU SESBANIAEffect of Sesbania green manuring on grain yield (t ha-1) of rice and wheat at Ludhiana, India.Sumber: ….. Diunduh 10/3/2012
84 PUPUK HIJAU SESBANIAChanges in content (mg kg-1 soil) of different fractions of iron, manganese, and zinc with Sesbania green manure in rice-wheat system at Ludhiana, India
85 MEMPRODUKSI PUPUK HIJAU As a draft animal farmer, you crop a large farm. You may not always have enough dung or compost to improve all plots of your farm. To keep all plots fertile, you need green manure in addition.Green manure is manure from special manure plants or crop residues.Many Green Manure Plants do not produce direct food, but they improve the soil. Plants that are cropped after applying green manure produce a lot of food.Some popular green manure plants are the following ones:Tephrosia - Sesbania - Crotalaria - Leucaena - Pigeon pea In addition, green manure plants have many other advantages.Sumber: Permanent Farming Systems Based on Animal Traction: Farmers Handbook (GTZ, 1995, 183 p.). PART V: The permanent farming system….. Diunduh 10/3/2012
86 Green manure plants have many benefits.. Green manure plants are planted:-in mixture with food crops; -on contour bonds, and . -as a sole crop on fallow areas.Sumber: Permanent Farming Systems Based on Animal Traction: Farmers Handbook (GTZ, 1995, 183 p.). PART V: The permanent farming system….. Diunduh 10/3/2012
87 PUPUK HIJAU - TANAMAN PANGAN If you mix green manure crops with food crops, you produce food and manure at the same time. You may not have the same yield as with sole cropping of food crops in the first year, but in the following years, you will harvest more on the green manure field, because you conserve and improve your soil by this method.A mixed crop of maize and sesbaniaSumber: Permanent Farming Systems Based on Animal Traction: Farmers Handbook (GTZ, 1995, 183 p.). PART V: The permanent farming system….. Diunduh 10/3/2012
88 MENANAM PUPUK HIJAUThe planting of green manure crops on the contour bonds has the following advantages: you reinforce and enrich your contour bonds through the root system of the green manure crop (tephrosia, sesbania, etc.) the green manure plant can be left for seed production after the seed harvest, the green manure plant can be pruned and used as manure for the field between the contour bonds.Fresh branches and leaves of the green manure crop can be cut and spread as mulch m the field.Sumber: Permanent Farming Systems Based on Animal Traction: Farmers Handbook (GTZ, 1995, 183 p.). PART V: The permanent farming system….. Diunduh 10/3/2012
89 BERO DENGAN TANAMAN PUPUK HIJAU If you have a very poor soil, you may have to fallow your farm Under natural fallow, it will take long time until the soil becomes fertile againUnder a planted fallow with Green Manure Plants, the soil becomes fertile again within 1 or 2 years.Green Manure Plants can give tons of fresh organic matter per hectare per year. This will save you a lot of fertilizer.Sumber: Permanent Farming Systems Based on Animal Traction: Farmers Handbook (GTZ, 1995, 183 p.). PART V: The permanent farming system….. Diunduh 10/3/2012
90 BAGAIMANA MEMBENAMKAN BAHAN ORGANIK? To avoid loss and improve the decomposition of organic matter from plant drop, we have to mix it with the soil. The oxen farmer uses the cart, the roller cutter and the ridger for this exercise.With the cart, he transports the manure to the farm.With the roller cutter, he can clear plant residues.With the ridger, he buries the organic matter into the soil.How to bury organic matter in a ridged field.The buried organic matter gives humus to the soil. We call this organic farming. It improves your soil and the following crop will produce a lot of food.Sumber: Permanent Farming Systems Based on Animal Traction: Farmers Handbook (GTZ, 1995, 183 p.). PART V: The permanent farming system….. Diunduh 10/3/2012
91 MIXED CROPPINGTo conserve and improve our soil, we have to practice mixed cropping. Mixed cropping is the planting of two or more crops on the same field at the same time.To keep the soil in balance, we combine (mix) crops which make the soil poor, with crops which improve the soil.Beberapa jenis tanaman yang dapat mengakibatkan penurunan kualitas tanah:maize - rice - wheat - yam - cassava - cocoyam - potatoesBeberapa jenis legume yang dapat memperbaiki kualitas tanah:- ground nuts - beans - soya beans - peas - green manure plantsSumber: Permanent Farming Systems Based on Animal Traction: Farmers Handbook (GTZ, 1995, 183 p.). PART V: The permanent farming system….. Diunduh 10/3/2012
92 A crop of maize mixed with beans MIXED CROPPINGApart from soil conservation, mixed cropping has a lot of other advantages: a mixture of crops with different root systems will use the different layers of the soil better, that means: they use the available water and nutrients better.mixed crops with different preferences for nutrients, use the different minerals available in the soil better.mixed cropping results in a higher plant population per unit area and increases yields. the higher plant density in mixed cropping reduces soil erosion and suppresses weed growth.mixed cropping reduces the risk of pests and diseases infestation.mixed cropping diversifies the food supply. You have different quality food for your family diet.mixed cropping reduces the risk of complete crop failure. If one crop fails, the other crops can still produce enough food for the farmer family.A crop of maize mixed with beansSumber: Permanent Farming Systems Based on Animal Traction: Farmers Handbook (GTZ, 1995, 183 p.). PART V: The permanent farming system….. Diunduh 10/3/2012
93 PERGILIRAN TANAMANIf the same crop is grown in the same field every cropping cycle:-the soil becomes poor; -pest and disease infestation increases; -the harvest gets smaller.If the crops change on the same field every cropping cycle:the soil does not become poor;pests and diseases do not increase easily;the harvest can stay good. To change crops on the same field every cropping cycle is called crop rotation.The advantages of crop rotation are similar to mixed cropping: Crop rotation:conserves the soil fertility: Crops which make the soil poor are followed by crops which enrich and improve the soil; e.g. Maize followed by beans.controls pests and diseases; Pests and diseases developing on one crop cannot affect a crop of another family; e.g. Cocoyam followed by Cassava.improves the use of different layers of the soil; Crops with a shallow root system are followed by crops with a deep root system; e.g. Beans followed by Cassava.improves the use of different minerals available in the soil; e.g. Cereals need more nitrogen while tuber crops need more potassium.Sumber: Permanent Farming Systems Based on Animal Traction: Farmers Handbook (GTZ, 1995, 183 p.). PART V: The permanent farming system….. Diunduh 10/3/2012
94 POLA TANAM PUPUK HIJAUTo get all possible advantages, combine mixed cropping with crop rotation. Recommended crop rotations with mixed crops for different areas of altitude are indicated on the following pages.[TREATMENTS - CROP ROTATION ON MEDIUM ALTITUDE (lower than 1500m)INDIVIDUAL PLANTING ARRANGEMENTS Treatment 1 or Plot 1 (between first and second contour bond) Maize and Green Manure:Distance between ridges: 80 cm.Distance between maize plants on the ridge: 25 cm.Maize and Green Manure on alternate ridges.Sumber: Permanent Farming Systems Based on Animal Traction: Farmers Handbook (GTZ, 1995, 183 p.). PART V: The permanent farming system….. Diunduh 10/3/2012
95 JAGUNG DENGAN PUPUK HIJAU Maize on ridges, green manure in the furrow. Distance between ridges: 80 cm.Distance between maize plants on the ridges: 30 cm.Green Manure Crops can be Tephrosia, Sesbania, Crotalaria solely or as a mixture.Sumber: Permanent Farming Systems Based on Animal Traction: Farmers Handbook (GTZ, 1995, 183 p.). PART V: The permanent farming system….. Diunduh 10/3/2012
96 TUMPANGSARI LEGUME DENGAN NON-LEGUME Treatment 2 or Plot 2 (between second and third contour bond) Maize and Beans and Cocoyam:Maize and Cocoyam/Beans are planted on alternative ridges.]Distance between the ridges: 80 cm. Distance between maize plants on the ridges: 25 cm. Distance between the cocoyam: 60 cm. Beans interplanted between cocoyam: cm distanceNOTE: - Split maize ridges after harvest and add soil to Cocoyam edge.
97 JAGUNG + PUPUK HIJAU LEGUME Treatment 3 or Plot 3 (between third and fourth contour bond)Maize and Food Legume are planted on alternate ridges.Legumes and maize mixed - Food legumes and potatoes mixed.First SeasonMaize and Food Legume: (Beans, Soyabeans, Groundnut) Distance between the ridges: 80 cm. Distance between the maize plants on the ridges: 25 cm. Distance between the food legumes: cm. (see Chapter 6.4.)Second Season:Food Legume and maize on 80 cm. ridges or Food Legumes on 50 cm. ridges or Food Legumes and potatoes on 80 cm. ridges or Potatoes or Sweet potatoes only or Green Manure.
98 PENANAMAN PUPUK HIJAU LEGUME Treatment 4 or Plot 4 (between fourth and fifth contour bond)First Season:Food legumes (Beans, Soyabeans, Groundouts). Food legumes are cropped solely on ridges. Distance between the ridges: cm. Distance between the plants on the ridges: cm.Or Potatoes (high altitude areas): Distance between the ridges: 80 cm. Distance between the plants on the ridges: cm.Potatoes are cropped solely on ridges or on alternate ridges with food legumes.Sumber: Permanent Farming Systems Based on Animal Traction: Farmers Handbook (GTZ, 1995, 183 p.). PART V: The permanent farming system….. Diunduh 10/3/2012
99 Nutrient Cycling in Agroecosystems . Volume 73, Numbers 2-3, 181-189 Effect of Green Manure Addition on Soil Organic Phosphorus MineralisationParmjit S. Randhawa, Leo M. Condron, Hong J. Di, Sokrat Sinaj and Roger D. McLenaghenThe mineralization of organic forms of phosphorus (P) in soil contributes significantly to plant P uptake, although quantification of organic P mineralisation has been impeded by methodological difficulties. An isotopic dilution method, based on tracer kinetic theory, was used to study the organic P flux rates for unamended and green manure amended soil in an incubation experiment carried out over 35 days. Firstly, the specific activity (SA) between two points of time as affected by dominant biological processes (under conditions of constant soil respiration rates) was determined in a series of successive labelling incubation experiments. Secondly, the instantaneous specific activity (instSA) between two points of time was also determined by shaking an unlabelled soil with 33P, i.e. soil samples that were not labelled with 33P, but kept under conditions identical to the labelled soil samples. This gives the net size of the exchangeable inorganic P pool in the labelling experiments at two points of time during incubation. The SA dilution in the labelling experiments at a constant exchangeable inorganic P pool between two times was attributed to the release of non-labelled inorganic P from the organic P pool by mineralisation. The daily gross organic P mineralisation rates for the 21 days of incubation were 0.06 and 0.27 mg P kg−1 day−1 for unamended and green manure amended soils, respectively. The study demonstrated that green manure amendment contributed to an overall increase in soil P availability through enhanced organic P mineralisation.Sumber: ….. Diunduh 10/3/2012
100 Volume 52, Number 3, 199-205, DOI: 10.1023/A:1011896705132 Agroforestry SystemsVolume 52, Number 3, , DOI: /A:Tithonia diversifolia: variations in leaf nutrient concentration and implications for biomass transferT. S. George, P. J. Gregory, J. S. Robinson, R. J. Buresh and B. A. JamaGreen leaf biomass of Tithonia diversifolia is high in nutrients and recognised as a potential source of nutrients for crops. We conducted a field survey in western Kenya to determine the variation in leaf nutrient concentrations in tithonia grown in naturalised hedges and agricultural fields, and to examine whether leaf nutrient concentrations were related to soil nutrient status.Leaf P and K concentrations were higher in naturalised hedges (3.2 g P kg–1 and 35 g K kg–1) than in unfertilised fields (2.2 g P kg–1 and 23 g K kg–1). The critical level of 2.5 g P kg–1 for net P mineralisation was exceeded by > 90% of the leaves from hedges, but by only 14% from unfertilised fields. Leaf P and K concentration increased linearly with increasing natural logarithm of anion resin extractable soil P and exchangeable soil K, respectively. However, at the same levels of soil available P and K, field-grown tithonia consistently produced lower leaf P and K concentrations than that grown in hedges.This study indicates that biomass from tithonia planted on nutrient-depleted soils would be a less effective source of P and K, via biomass transfer, than tithonia from naturalised hedges.Sumber: ….. Diunduh 10/3/2012
101 The Journal of Agricultural Science (1994), 122 : pp 359-364 Effect of green manuring with dhaincha (Sesbania aculeata) on growth and yield of direct-sown and transplanted rice under intermediate deepwater conditions (0–50 cm)R. Sharma and K. C. DasThe Journal of Agricultural Science (1994), 122 : ppIn intermediate deepwater conditions (0–50 cm) at Cuttack, India during 1990 and 1991, rice and dhaincha (Sesbania aculeata) were either mixed-sown in different arrangements (parallel lines and mixed broadcasting) in dry soil by the end of May or rice seedlings were transplanted in plots grown with pure dhaincha after the accumulation of water in the field by mid-July.Incorporation of dhaincha in situ after 48 and 54 days of growth added 60·8–65·2 and 72·9–76·9 kg N/ha in the mixed stands compared with 81·3 and 85·1 kg N/ha in the pure stand in 1990 and 1991 respectively. Although the growth of rice when sown simultaneously with dhaincha was affected initially due to the more vigorous growth and shading by the latter, tillering of rice increased after the incorporation of green manure following an increase in inter-row spacings.The performance of the direct-sown and transplanted rice was similar in 1990, when the water level rose relatively slowly, but in 1991 the transplanted crop yielded significantly less due to the sudden accumulation of water to higher depths (48 cm), resulting in greater mortality of seedlings at planting. However, the grain yield of both directsown and transplanted crops increased with dhaincha green manuring compared with the control (no application of dhaincha) and was equal to the application of 40 kg N/ha applied as urea fertilizer.The highest yield was obtained when rice and dhaincha were grown at a 2:1 ratio in 20 cm wide rows and the clonal tillers uprooted from the adjoining rice rows were planted in lines vacated by dhaincha. The yield was, however, equal to that from treatments where rice and dhaincha were grown in alternate rows at 15 cm spacing or mixed broadcasting. Increase in yield under green manuring was due to greater panicle weight, which was probably due to a continued supply of N following decomposition of organic matter added through dhaincha. Therefore, green manuring of direct-sown rice with dhaincha was beneficial for higher crop productivity under excess water conditions.Sumber: ….. Diunduh 10/3/2012
102 Effect of green manure amendment and flooding on methane emission from paddy fields Shang-Shyng Yang, , Hsiu-Lan ChangChemosphere - Global Change ScienceVolume 3, Issue 1, January 2001, Pages 41–49The effect of green manure amendment, flooding treatment and crop season on methane emission from paddy fields in Taiwan was investigated from August 1994 to July 1996.Sesbania amendment stimulated methane emission and the effect was more significant at the early growth stage of rice. Methane emission was higher in continuous flooding treatment than that in intermittent irrigation. Both redox potential and methane emission showed significant differences between these two irrigation systems.Methane concentration increased sharply with the depth of soil in the intermittent irrigation system due to oxidation; whereas it increased moderately in the continuous flooding treatment.The seasonal methane flux in the first crop season with chemical fertilizer was between 2.73 and 5.23 g m−2; while the value was between and g m−2 in the second crop season. In the case of Sesbania amendment in the second crop season, the seasonal methane flux in the first crop season was 6.35 g m−2; while the value was between and g m−2 in the second crop season.Total methane emission in the second crop season was about two to five-fold higher than that in the first crop season.Sumber: ….. Diunduh 10/3/2012
103 Title of Thesis PRODUCTIVITY AND RESIDUAL EFFECTS OF GREEN MANURE LEGUMES IN CEREAL-BASED CROPPING SYSTEM IN POTHOWAR PLATEAUMuhammad Ibrahim SultaniUniversity of Arid Agriculture/Range Management and Forestry Session. 2004Investigations which included two experiments were carried out at the National Agricultural Research Centre (NARC), Islamabad, Pakistan during In first experiment effect of different green manuring crops namely Cyamopsis tetragonaloba (L), Vigna umbelate (Thumb) and Sesbania aculeata (Linn) and levels of phosphorus fertilizer (0, 30, 60 and 90 kg ha-1) on biomass of green manure crops, organic matter addition as of incorporation of biomass, improvement in N soil fertility status, impact on physical properties and ultimately productivity of wheat was investigated. The second experiment was carried to investigate the effect of phosphorus sequencing and green manure crops mentioned in experiment one on various parameters mentioned above.Results of the experiment indicated that maximum fresh biomass (22.57 t ha-1) and dry biomass (4.33 t ha-1) was produced by Sesbania aculeata followed by fresh biomass of Cluster bean (19.31 t ha-1) and dry biomass (3.70 t ha-1). Lowest fresh biomass was produced by Rice bean (16.86 t ha-1) and dry biomass (3.25 t ha-1). Application of P further enhanced above ground green biomass production upto t ha-1. Incorporation of Sesbania biomass as green manures on the average increased soil organic matter by 20%, N by 23 %, P by 71 % and K by 29%; these manures further significantly reduced soil bulk density (5%), enhanced porosity (8%), moisture retention (5%) and available water (17%).Green manure increased total biomass of succeeding wheat crop by 16%. There was significantly positive interaction of green manure legumes and P fertilization by 20%. Furthermore their integrated residual effect of 3% to 5% was noted on various parameters in the succeeding crop year.Sumber: ….. Diunduh 10/3/2012
104 Sumber: http://orgprints.org/12010/ ….. Diunduh 10/3/2012 Mazzoncini, Marco; Migliorini, Paola; Antichi, Daniele and Vazzana, Concetta (2008)Effects of green-manure and organic fertiliser on organic maize (Zea Mays L.) in south Tuscany.Poster at: Cultivating the Future Based on Science: 2nd Conference of the International Society of Organic Agriculture Research ISOFAR, Modena, Italy, June 18-20, 2008.Green-manure in Mediterranean stockless organic farms is a useful tool to improve nitrogen availability, reduce production cost and conserve soil fertility.A 2-year on farm research was carried out in Tuscany (Italy) to evaluate the effect of 3 different green manures (Hordeum v. + Avena s. mixture, Trifolium s. + Avena s. mixture, Vicia faba var. minor) and 2 levels of organic N fertilization (0 and 120 Kg N ha-1) on maize in 2004 and 2005.Green manures were ploughed into the soil in April 2004 and organic fertiliser was applied before sowing; neither green manure nor fertilizers were applied in 2005 to evaluate the residual effect of the treatments.The effect of the distribution of organic fertilizer was not efficient in comparison to green-manure. Field-bean increased maize productivity in both the years thanks to an increase in N availability as suggested by its total N uptake that exceeded the uptake of maize after control by 19.5 and 14,3 Kg N ha-1 in the first and second year.In our experimental conditions, with low organic matter and nitrogen content in the soil, the use of grasses as green-manure caused temporary immobilisation of N and maize yield reduction.Sumber: ….. Diunduh 10/3/2012
105 The prediction model of protein content was weak. Effects of Green Manure, Organic Fertilizers and Urea on Yield and Grain Quality of Spring WheatMaria Wivstad, Lennart Salomonsson & Ann-Christine SalomonssonActa Agriculturae Scandinavica, Section B - Soil & Plant ScienceVolume 46, Issue 3, pagesEffects of two green manure crops—persian clover and persian clover/Westerwolth ryegrass—and three fertilizers—liquid manure, meat bone meal and urea-on subsequent spring wheat yields and quality characters were studied in four field experiments.No significant differences between green manure crops in production or effects on wheat were found. The yield was up to 2500 kg/ha higher after the green manure crops than after oats, but the effect on wheat protein content was less pronounced.Fertilization did not increase the yield as much as green manuring, but significantly increased protein content in two of the experiments. In a partial least square regression (PLSR) model, the wheat yield was largely explained by the amount of green manure herbage ploughed in during the autumn and the amount of mineral N in the soil in spring.The prediction model of protein content was weak.Sumber: ….. Diunduh 10/3/2012
106 N. Ochiai, M. L. Powelson, R. P. Dick and F. J. Crowe PLANT DISEASE . April 2007, Volume 91, Number 4 PagesEffects of Green Manure Type and Amendment Rate on Verticillium Wilt Severity and Yield of Russet Burbank PotatoN. Ochiai, M. L. Powelson, R. P. Dick and F. J. CroweIncreasing restriction of agrochemicals is motivating development of ecology-based cropping systems, including green manures, to manage soilborne diseases.Green manures have shown promise in suppressing Verticillium dahliae, but information about effect of different green manures and optimal application rates remains limited. Therefore, we conducted two single-year field experiments comparing effects of Austrian winter pea (Pisum sativum ‘Melrose’), broccoli (Brassica oleracea var. botrytis ‘Excelsior’), and Sudan grass (Sorghum vulgare var. sudanense ‘Monarch’), amended at 6, 12, or 24 Mg ha-1, on soil populations and root infection by V. dahliae, wilt severity, and yield of Russet Burbank potato.Inoculum density was reduced relative to the nonamended, infested control by all broccoli treatments, Austrian winter pea applied at 12 and 24 Mg ha-1, and Sudan grass applied at 12 Mg ha-1.Root infection was not reduced by any green manure treatment. Median wilt severity was reduced approximately 70% by all green manures applied at 24 Mg ha-1 and 74% by Austrian winter pea applied at 12 Mg ha-1.Tuber yield was reduced approximately 20% in nonamended, V. dahliae-infested controls relative to the noninfested controls. No green manure treatment improved yield relative to the nonamended, infested control.Sumber: Diunduh 10/3/2012
107 TANAMAN PUPUK HIJAULegumes fix nitrogen from the air as they grow, thus they can pro-vide nitrogen to the soil when used as a green manure. Legumes should be inoculated with the appropriate strain of nitrogen-fixing bacteria ( Rhizobium spp.) when they are sown to ensure efficient fixation.The total plant nitrogen that is fixed is much less for plants growing in soils with abundant nitrogen than in soils poor in nitrogen. Before legumes fix nitrogen from the air, they will use nearly all avail-able nitrogen in the soil.The maximum amount of nitrogen uptake occurs in the first percent of the legume's growing period (Allison 1973).The nitrogen content increases steadily during growth of the legume until the plants reach seed production, then it levels off.The range of values of nitrogen fixed varies widely but is estimated to be: alfalfa , clovers , peas , and pastures with legumes pounds per acre per year (Allison 1973).Sumber: ….. Diunduh 10/3/2012
108 KANDUNGAN N BIOMASA LEGUME Nitrogen content of tops and roots of legumes, and the amount of nitrogen fixedSumber: ….. Diunduh 10/3/2012
109 EFEK BAIK DAN BURUK PUPUK HIJAU Green manure is usually beneficial to soil that is well managed.Benefits attributed to green manuring include addition of nitrogen (when using legumes), addition of organic matter, increase in the conservation and availability of nutrients, improved physical condition of the soil erosion control, and weed and disease control. The root systems of green manure crops also have a big effect in aggregation of the finer-textured soils, as discussed above. The most effective root systems forthis purpose are those with finely divided and extensive, but not necessarily deep roots. Small-grain crops best meet this requirement.Green manure crops also shade and cool the soil. By providing a dense vegetative cover, the damage to soil aggregation produced by raindrop splash is eliminated (Allison 1973). This reduces the tendency toward crust formation, a serious problem in many nurseries.Green manuring is often used in rotation in agriculture for disease control. But the common pathogens of tree seedlings, such as Pythiumspp., Fusarium spp., and Rhizoctonia spp., have a wide host range and their incidence does not appear greatly affected by crop rotation (Aldhous1972). The one exception found in the literature is with western red cedar seedlings.In England (Aldnous 1972), these seedlings can be infectedby the fungus disease Didymascella (Kethia) thujina, causing severe losses. Aggravation of losses occurs from cross-infection of first year seedbeds from older stock.Crop rotation is an effective control because it en-sures that cedar is not grown in seedbeds for more than one year.Sumber: ….. Diunduh 10/3/2012
110 EFEK PUPUK HIJAUThere is some disagreement about whether green manure actually provides an increase in the organic content of the soil. It appears that green manures may have a negligible effect on total levels of soil organic matter under systems of continuous cultivation (Allison 1973).They do add active, rapidly decomposing organic material. The actualpercent organic matter in soils may be determined primarily by climate.Higher levels may be obtained by replacing crops with sod or periodicadditions of organic material such as animal manure.Green manuring involves soil disturbance, and accelerated oxidation would counteract some of the possible increases that could be expected. Beneficial effects of green manuring are generally evident from other characteristics associated with addition of organic material.Sumber: ….. Diunduh 10/3/2012
111 EFEK BURUK PUPUK HIJAUMost of the harmful effects related to green manure occur onlywhen the crop that follows is grown too soon after plant material isincorporated. Seedlings grown too soon after turning under a greenmanure crop are sometimes injured by damping-off fingi (Allison 1973).A green manure crop can deplete soil moisture temporarily while itdecomposes. This problem is more critical with dry-land farming inareas of low rainfall. With irrigation, it is not a serious concern. Incor-poration of non-legumes with high carbon-to-nitrogen ratios may de-plete soil nitrogen during decomposition and depress uptake by suc-ceeding crops.To avoid this, supplemental nitrogen fertilizer can be added at the time the nonlegume is incorporated. For a short period after such material is incorporated, there can also be an inhibiting and toxic effect on seedlings from high concentrations of nitrites and non-ionized ammonia (Allison 1973). After a few days, this does not appear to be a problem.Sumber: ….. Diunduh 10/3/2012
112 Some plants known to have produced growth inhibitor. SUBSTANSI FITOTOKSIKToxic organic substances may be formed by some plants grown as agreen manure crop. Phytotoxic substances are formed by some higher plants and micro-organisms associated in their decomposition. Antibiotics produced by soil organisms can also be toxic to some plants. Harmful products derived from green manures are usually destroyed within 2 to 3 weeks. Antibiotics are generally adsorbed by soil colloids (Allison 1973).Some plants known to have produced growth inhibitor.Unfortunately, little information is available regarding inhibition of tree seedling growth by other plants, but some indications of allelopathic plants important to forestry.Sumber: ….. Diunduh 10/3/2012
113 BEBERAPA TUMBUHAN ALELOPATI Some allelopathic plants important in forestry, chemicals they produce and plants they affectSumber: ….. Diunduh 10/3/2012
114 PEMILIHAN TANAMAN PUPUK HIJAU Ideally, a green manure crop should be easilyestablished and grow rapidly. There are a variety of legumes and nonlegumesthat produce abundant growth in a short time. Choice of the cropshould include consideration of the purpose for green manuring andclimatic factors.Plants reported to produce differential growth inhibitors of known and unknown composition (Allison , 1973).Sumber: ….. Diunduh 10/3/2012
115 BEBERAPA TANAMAN PUPUK HIJAU Commonly used green manure crops and theadaptability to difference climatesSumber: ….. Diunduh 10/3/2012
116 EFFECT OF GREEN MANURE LEGUME ON THE YIELD OF MAIZE AND BEANS IN MATUNDA FARM, TRANS NZOIA DISTRICT, NORTH RIFT KENYAKAMIDI M.1, 2F. GITAHI, 1P. OSORE, 1D. CHERUIYOT, 2M. OKUMU and 2G. BARASA.1 Kenya Agricultural Research Institute, National Agricultural Research Centre Kitale, P.O. Box 450, Kitale2District Agricultural Officer, Trans Nzoia District, P.O. Box 1781, Kitale.Maize and bean yields in Matunda farm, Trans Nzoia District are usually low due to non-use or use of sub-optimal amounts of inorganic fertilisers. Though farmers make and use compost, the amounts available are not adequate to cover a large area. A study was carried out to evaluate legume green manure species as a supplement to the expensive inorganic fertilisers on maize and bean grain yields.In 1997, five legume treatments: Mucuna (Mucuna pruriens), soybeans (Glycine max), dolichos (Lablab purpureus), sunhemp (Crotalaria ochroleuca) and cowpeas (Vigna unguiculata) were relay planted in a maize crop after bean harvest. The legume species were replicated on six farms in a randomized complete block design.They were incorporated in the field and maize and beans planted at the on-set of rains in 1998 using fertiliser rates of 30 kg P2O5 ha-1 and 30 kg N ha-1. In August 1998, the legumes were relay cropped in the same plots but with purple vetch replacing cowpeas. This was followed by maize/bean intercrop at the on-set of rains in 1999 using the same amount fertilisers as in 1998.The combined use of green manure and 30 kg P2O5 ha-1 and 30 kg N ha-1 significantly (P<0.05) increased maize yield compared to use of 30 kg P2O5 ha-1 and 30 kg N ha-1 or green manure alone.Sumber: ….. Diunduh 11/3/2012
117 Moisture Content and Availability. The effect of green manuring on the physical properties of temperate-area soils.MacRae, R.J. and G.R. Mehuys Advances in Soil Science, Volume 3:Soil Aggregates.Organic matter plays more of a role in aggregate stability than in aggregate formation. It is, in fact, the primary stabilizing agent for aggregates in temperate-area soils. This stabilization process is accomplished mainly through the by-products of organic matter decomposition (microbial gums and mucilages).Bulk Density."With few exceptions, organic matter decreases the bulk density of soil." This effect can occur either directly by "diluting" the soil with a less dense material, or indirectly through greater aggregate stability. Indirect effects seem to be the most important and are not dependent on soil textural class.Moisture Content and Availability.Soil organic matter has a variable effect on available water in soil. It is generally a positive relationship, but whether or not the effect is significant depends on other soil properties, notably texture. One experiment, for example, found organic matter to influence available water only in soils of medium to low clay content (13 to 20 percent); otherresearchers concluded that coarse silt, not organic carbon, was the primary factor determining available water in mineral soils. It is important to distinguish between water retention and water availability. Some sources of organic matter (like peat moss) have high water retention (i.e. they increase soil water holding capacity), but a portion of this water may be held so tightly that it is not available to plants. Increased soil aggregation can have a similar effect.Water Movement.Organic matter has a strong, positive effect on infiltration of water into soils. This effect is due mainly to a decrease in bulk density, and improvements in aggregation and structure.Sumber: ….. Diunduh 11/3/2012
118 Effect of Green Manures on Soil Organic Matter The effect of green manuring on the physical properties of temperate-area soils.MacRae, R.J. and G.R. Mehuys Advances in Soil Science, Volume 3:Effect of Green Manures on Soil Organic MatterThe maintenance or accumulation of organic matter in soils depends on a number of factors including: characteristics of the added material, soil and climatic factors as they affect microbial activity, and agricultural practices. All other factors being equal, it is generally accepted that low-nitrogen green manures (1.5 percent N or less) can be effective in improving soil organic matter levels. High-nitrogen materials such as legumes, on the other hand, cannot maintain organic matter levels because they decompose too rapidly. Varied reports from the literature suggest that each plant species should be considered on its own merits and in the context of the farming systems in which it will be used. Table presents a sample of how diverse the literature is on this subject. Any interpretation of these varied results should also take into account soil type, soil nitrogen levels, native soil organic matter levels and microbial activity.StudyLength of study (Years)Soil TypeOM %Initial SoilN %Changes at end of study:OM Soil NPotting StudiesPrince (1941)40Loam3.90.19DecreaseDe Haan (1977)10Sand0.15IncreaseClay3.00.22Field StudiesPoyser (1957)257.80.37Mann (1959)18Sandy loam1.50.09continued from Mann (1959)Charter et al. (1970)using Trefoil301.48Sameusing ryegrassSumber: ….. Diunduh 11/3/2012
119 The effect of green manuring on the physical properties of temperate-area soils. MacRae, R.J. and G.R. Mehuys Advances in Soil Science, Volume 3:Effect of Green Manures on Soil Physical Condition and Crop PerformanceThe authors next address two practical questions: Are green manures, used in a field situation, capable of improving soil physical properties in the same way that other forms of organic matter do? And the related question: Can the use of green manures improve crop performance?Green Manures and Soil Physical Properties.The same characteristics evaluated in the first section of this paper are also evaluated here: aggregate distribution and stability, bulk density, moisture content and availability, and water movement. Though limited, the literature on green manure effects is generally consistent with that on the effects of organic matter per se.Green Manures and Crop Performance.It is an accepted fact that improvements in soil physical condition create the potential for increased crop growth. It is, however, difficult to assess this relationship quantitatively, and to determine the degree of improvement necessary to effect a significant increase in crop yield. Researchers who have looked at corn production report that increased corn yields are associated with improvements in the physical condition of the soil. Due to limitations in experimental design, they were unable to differentiate the effect of enhanced soil fertility from the effects of an improved physical environment. One definitive point can be made: The benefits of green manuring on crop yield are most apparent during dry periods, particularly in rainfed production systems.Sumber: ….. Diunduh 11/3/2012
120 Effect of green manure legume - maize rotation on maize grain yield and weed infestation levelsJude J. O. Odhiambo, John B. O. Ogola and Thendo Madzivhandila.African Journal of Agricultural Research Vol. 5(8), pp , 18 April, 2010The use of green manure legumes (GLM) as cover crops in rotation with maize has the potential to enhance maize yields. The objectives of this study were to determine the effect of GML - maize rotation system on (i) maize growth and yield and, (ii) weed infestation levels. The two year (2007/8 and 2008/9 seasons) rotation system consisted of five GML cover crops, viz. mucuna, lablab, sunhemp, cowpea and butterfly pea followed by maize.GML biomass ranged between 0.8 and 13.6 Mg ha-1, while nitrogen (N) content ranged between 10 and 279 kg N ha-1. Maize grain yield following GML ranged between 2.6 and Mg ha-1. In 2007/8 season cowpea, mucuna, lablab and sunhemp plots had a lower weed dry matter (5.30, 11.97, 5.83 and g m-2, respectively) than the control (+N) (49.47 g m-2).In 2008/9 season, at WAP, control (+N) had a higher weed dry matter than the other treatments, except of butterfly pea. The dominant weed species were Mexican ricardia (Ricardia brasiliensis), Yellow nutsedge (Cyperus esculentus), Guinea-fowl grass (Rottbollia cochinchinesis), Witch weed (Striga asiatica), Bermuda grass and Cynodon species. Green manure legume fallows can increase maize grain yield significantly and suppress the weed population as compared to natural fallow. However, maximizing biomass production and N accumulation is critical in order to reap the benefits of green manure. Hence, integrating GML into the existing cropping system will require that appropriate timing for planting GML be well established.Sumber: ….. Diunduh 11/3/2012
121 Effect of green manure legume - maize rotation on maize grain yield and weed infestation levelsJude J. O. Odhiambo, John B. O. Ogola and Thendo Madzivhandila.African Journal of Agricultural Research Vol. 5(8), pp , 18 April, 2010Hasil biji jagung musim tanam tahun 2007/8 dan 2008/9. [Con (-N) = Control (-N); Con (+N) = Control (+N); CP = Cowpea; MC = Mucuna; LL = Lablab; BP = Butterfly pea; SH = Sun hemp].Sumber: ….. Diunduh 11/3/2012
122 Cuban Journal of Agricultural Science, Volume 45, Number 1, 2011. Effect of green manure from Tithonia (T. diversifolia) on the establishment and production of forage of P. purpureum cv. Cuba CT-169 and on some soil propertiesG. Crespo, T. E. Ruiz and J. ÁlvarezIn an experimental design of random blocks with four replicates, it was studied the effect of applying three doses of green manure of tithonia (0, 12, and 24 t/ha) on the establishment and production of biomass from P. purpureum cv. Cuba CT-169 forage and on some indicators of red ferrallitic soil.In the first establishment cut, there was no effect of the treatments on the height of the plants. However, the number of tufts/m2 (2.4 – 2.5), the number of tillers/plant (10.4 – 10.6), and the DM yield /ha (16.2 – 18.6 t) were increased significantly in the treatments with green manure, without significant differences between the doses applied. In the second cut (residual effect), conducted three months after the first (February 2009), there were no differences either between treatments for the height of the plants, but the indicators tufts/m2, tillers/plant, and DM yield were increased significantly up to the highest dose of green manure application.Aplikasi pupuk hijau hingga dosis tertentu secara nyata menurunkan bobot isi tanah (1.01, 0.79, dan 0.68 g/cm3 dengan dosis 0, 12, dan 24 t/ha) dan meningkatkan kandungan BOT (4.2%) dan N-total (0.30%).Penggunaan T. diversifolia dianjurkan sebagai pupuk hijau untuk memperbaiki kesuburan tanah dan meningkatkan produksi hijauan Cuba CT-169 pada tanah feralitik merah.Sumber: ….. Diunduh 11/3/2012
123 Cuban Journal of Agricultural Science, Volume 45, Number 1, 2011. Effect of green manure from Tithonia (T. diversifolia) on the establishment and production of forage of P. purpureum cv. Cuba CT-169 and on some soil propertiesG. Crespo, T. E. Ruiz and J. ÁlvarezEffect of the green manure of tithonia on indicators of the Pennisetum purpureum cv. CT-169 yield on the first cut (November 2008)Effect of green manure on the density and some chemical indicators of the soilSumber: ….. Diunduh 11/3/2012
124 Effect of Chinese milk vetch (Astragalus sinicus L Effect of Chinese milk vetch (Astragalus sinicus L.) as a green manure on rice productivity and methane emission in paddy soilChang Hoon Lee, Ki Do Park, Ki Yuol Jung, Muhammad Aslam Ali, Dokyoung Lee, Jessie Gutierrez, Pil Joo Kim.Agriculture, Ecosystems & EnvironmentVolume 138, Issues 3–4, 15 August 2010, Pages 343–347This field study was undertaken to investigate the optimum recycling rate of the above ground biomass of Chinese milk vetch (Astragalus sinicus L. hereafter, vetch) to improve rice productivity and decrease seasonal methane (CH4) flux in mono-rice cultivation system. The above ground part of vetch was applied in paddy field at rates 0, 10, 20 and 40 Mg ha−1 on fresh weight basis to investigate its effect on rice (Oryza sativa) productivity and CH4 emission flux and was compared with the typical standard NPK chemical fertilization (N–P2O5–K2O = 90–45–58 kg ha−1).Rice productivity increased significantly with increasing vetch application, and more interestingly, similar grain yield was obtained between vetch application at 10 Mg ha−1 as green manure and NPK fertilization. Methane emission rates, which were measured by closed-chamber method, increased significantly (p < 0.05) with increasing application levels of vetch, and seasonal CH4 fluxes exceeded to that in NPK fertilization at over 10 Mg ha−1 vetch application. Our findings revealed that 10 Mg ha−1 vetch application as green manure amendment can be an effective application level of sustaining rice productivity without increasing CH4 emission compared to NPK fertilization in Korean mono-rice cultivation systems.Sumber: ….. Diunduh 11/3/2012
125 PUPUK HIJAU PADA PADI SAWAH Changes of rice grain yield and CH4 flux in paddy soil amended with different rates of Chinese milk vetch as a green manure during rice cultivation. NPK treatment was fertilized by only chemical fertilizer (N–P2O5–K2O = 90–45–58 kg ha−1).Sumber: ….. Diunduh 11/3/2012
126 FUNGSI BOTFungsi bahan organik tanah, interaksi terjadi di antara fungsi-fungsi tanah (Sumber: Baldock and Skjemstad, 1999).Sumber: ….. Diunduh 11/3/2012
127 BOT DAN PRODUKTIVITAS TANAH Relationship between organic C concentration in the surface 0-15cm of soil and soil productivity as determined by total dry matter yield at dryland sites in Alberta, Canada (redrawn from Janzen et al., 1992).Sumber: ….. Diunduh 11/3/2012
128 PUPUK HIJAU MENINGKATKAN KANDUNGAN BOT Effect of amendment carbon input rate and type on soil C accumulation (0-20cm) in a 30 year old Swedish field experiment (Paustian et al., 1992).Sumber: ….. Diunduh 11/3/2012
129 PUPUK HIJAU MENINGKATKAN KANDUNGAN BOT Changes in SOC content on the Hoosefield continuous barley experiment with no fertiliser applied (control), annual application of NPK fertiliser, annual application of FYM (35 t ha-1 ) and FYM applied from (modified from Haynes and Naidu, 1998).Sumber: ….. Diunduh 11/3/2012