1. KEBUTUHAN HARA dan PEMUPUKAN TANAMAN SAYURAN
Bahan kajian
MK. Pengelolaan Kesuburan Tanah
KEBUTUHAN HARA
dan
PEMUPUKAN
TANAMAN SAYURAN
Dihimpun dan diabstraksikan : Smno.jursntnh.fpub.Okt2012

2. Crop Rotation and Vegetable Nutrient Relationship
Understanding the vegetable nutrient relationship between your vegetables and your soil is an important aspect of organic gardening crop rotation. This relationship of plant and nutrient determines whether you have a successful long term, healthy organic garden, or a short term pest ridden garden. The principle I use to explain this comes from the world renowned biointensive gardener and author John Jeavons and his incredible book How to Grow More Vegetables.

3. Amanabo Musa and Emmanuel O. Ogbadoyi
. Asian Journal of Crop Science   Year: 2012 | Volume: 4 | Issue: 3 | Page No.: Effect of Nitrogen Fertilizer on the Levels of Some Nutrients, Anti-nutrients and Toxic Substances in Hibiscus sabdariffa
Amanabo Musa and Emmanuel O. Ogbadoyi
The presence of antinutrients and toxic substances in vegetables limits the derivable benefits from vegetables. The levels of these substances in vegetables are influenced by the nature of soil in which the vegetables are grown.
The effect of applied nitrogen fertilizer on the levels of some antinutrients and toxic substances is investigated with a view to determine the appropriateness or otherwise of the application of nitrogen fertilizer in growing vegetables.
Pot experiments were conducted to determine the effect of soil nitrogen levels on soluble and total oxalates, cyanide, nitrate and some micronutrients namely, vitamin C, β-carotene (precursor of vitamin A) and mineral elements (Fe, Mg, Zn, Cu, Ca, Na and K) in Hibiscus sabdariffa. The leaves of the vegetable were harvested and analysed at market maturity (vegetative phase) and fruiting (reproductive phase) of the plant development.
Results obtained showed that the applied nitrogen fertilizer significantly elevated nitrate and β-carotene contents, while it decreases the levels of vitamin C, soluble and total oxalates in the vegetable. The levels of cyanide and mineral elements were not significantly affected by the applied nitrogen fertilizer.
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4. HortScience April 1993 vol. 28 no. 4 267
NITROGEN LEVEL AND LIGHT INTENSITY CAN EFFECT VEGETABLE AMARANTH LEAF NUTRIENTS
D.J. Makus
HortScience April 1993 vol. 28 no
. Three-week-old transplants of Amaranthus tricolor cultivars 'RRC 241' (RC) and 'Hinn Choy' (HC) were given split applications of supplemental N of 0, 100 and 200 kg/ha and in the 5th week after sowing were exposed to 100, 70 and 50% of ambient solar radiation for nine and ten days, respectively. Increased shading had a linear (L) effect on leaf blade NO3, protein, K, Mg, S, P, Al, Fe and Cu (dry wt basis).
There were L and quadratic (Q) increases in chlorophyll (chloro) and carotenoids. Increasing supplemental N increased leaf blade protein (L,Q), Na (L), Mn (L), chloro (L,Q), carotenoids (L,Q), but decreased Mg (L), P (L,Q) and Zn (L,Q).
Nitrate levels showed L and Q increases in RC and HC, respectively. HC was higher in leaf blade K, Mg, Na, Fe, Zn, Cu, NO3, chloro and carotenoides, but lower in CA than RC. Shading had no effect on leaf area or plant fresh wt, but decreased plant dry wt while increasing plant water content.
Nitrogen application increased stem length, and plant fresh and dry wt.
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5. NITROGEN EFFECTS ON VEGETABLE CROP PRODUCTION AND CHEMICAL COMPOSITION
. ISHS Acta Horticulturae 506: International Workshop on Ecological Aspects of Vegetable Fertilization in Integrated Crop Production
NITROGEN EFFECTS ON VEGETABLE CROP PRODUCTION AND CHEMICAL COMPOSITION
J. Sorensen
Concerns about human health in relation to the intake of food have led to an increasing interest in the nutritional quality of food products. A high intake of vitamins, dietary fibres and some minerals, and a low intake of nitrate, is supposed to protect against several life-style diseases which occur in many industrialized countries.
Application of fertilizers may not only influence the yield and quality of field vegetable crops, but also the chemical composition of the marketable product. Therefore, application of fertilizers may be used to control and improve the nutritional quality of products used for human consumption. During the last two decades the chemical composition of field vegetable crops has been monitored in several fertilizer experiments at the Danish Institute of Agricultural Sciences.
This paper shows that increased N supply decreased the concentration of dry matter, potassium, sucrose, vitamin C, and dietary fibre in leaf vegetable crops, but increased the concentration of nitrate, nitrogen, and carotene.
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6. Journal of the Science of Food and Agriculture
Effect of nitrogen fertiliser on the nitrate contents of field vegetables grown in Britain
Duncan J. Greenwood, John Hunt
Journal of the Science of Food and Agriculture
Volume 37, Issue 4, pages 373–383, April 1986
. The nitrate and percentage organic nitrogen contents of 14 vegetable and two arable crops were measured after they had been grown with different levels of N-fertiliser. Foliage crops always contained substantial quantities of nitrate which increased with increase in the rate of N-fertiliser application.
Grain of legumes and cereals, storage roots of carrots, parsnips and sugar beet, and onion bulbs and leeks contained no detectable amounts of nitrate even when N-fertiliser application rates were very high. Storage roots of red beet, swede and white turnip contained more than 3 mg NON g−1 dry weight when grown with exceptionally high levels of fertiliser-N but contained very little when grown with the optimum amount of fertiliser-N or less. An equation was developed that linked NON to percentage organic-N for those parts of plants that could accumulate nitrate. It gave good fits to the data from seven crop species grown at a range of different levels of N-nutrition.
It is estimated from the foregoing data and a survey of household food consumption that the average British person consumes about 60 mg NON week−1 in field vegetables. If N-fertilisers were withheld consumption would be about 30 mg and if excess were applied it would be about 120 mg NON week−1.
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7. Effects of a catch crop and reduced nitrogen fertilization on nitrogen leaching in greenhouse vegetable production systems
Authors: Min, Ju1; Shi, Weiming2; Xing, Guangxi1; Zhang, Hailin3; Zhu, Zhaoliang1
Source: Nutrient Cycling in Agroecosystems, Volume 91, Number 1, September 2011 , pp (9)
Greenhouse vegetable cultivation has greatly increased productivity but has also led to a rapid accumulation of nitrate in soils and probably in plants. Significant losses of nitrate-nitrogen (NO3-N) could occur after heavy N fertilization under open-field conditions combined with high precipitation in the summer. It is urgently needed to improve N management under the wide spread greenhouse vegetable production system.
The objective of this study was to evaluate the effects of a summer catch crop and reduced N application rates on N leaching and vegetable crop yields. During a 2-year period, sweet corn as an N catch crop was planted between vegetable crops in the summer season under 5 N fertilizer treatments (0, 348, 522, 696, and 870 kg ha−1) in greenhouse vegetable production systems in Tai Lake region, southern China.
A water collection system was installed at a depth of 0.5 m in the soil to collect leachates during the vegetable growing season. The sweet corn as a catch crop reduced the total N concentration from 94 to 59 mg l−1 in leached water and reduced the average soil nitrate N from 306 to 195 mg kg−1 in the top 0.1-m soil during the fallow period of local farmers' N application rate (870 kg ha−1). Reducing the amount of N fertilizer and using catch crop during summer fallow season reduced total N leaching loss by 50 and 73%, respectively, without any negative effect on vegetable yields.
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8. Agricultural and Food Science
Effects of band placement and nitrogen rate on dry matter accumulation, yield and nitrogen uptake of cabbage, carrot and onion
T. SALO
Agricultural and Food Science
Vol 8, Nro 2 (1999)
Adequate nitrogen (N) nutrition is essential for producing high vegetable yields of good quality. Fertilizer N not taken up by the plants is, however, economically wasteful and can be lost to the environment. Therefore the efficient use of N fertilizer, involving accurate estimation of crop N demand, choice of application method and timing of N fertilization, is an important research area. The effects of band placement and rate of N fertilization on inorganic N in the soil and the dry matter accumulation, yield and N uptake of cabbage, carrot and onion were studied in a three-year field experiment between 1993 and The plants were sampled during the growing season to determine the dry matter accumulation and plant N concentration. The inorganic N in the soil was determined during the growing period and after harvest. The N uptake was 3.8 kg, 1.6 kg and 2.5 kg per ton of edible yield of cabbage, carrot and onion, respectively. At the highest yield levels the N uptake including crop residues was 300 kg ha-1, 150 kg ha-1 and 120 kg ha-1 in cabbage, carrot and onion, respectively. In cabbage, almost 50% of N was in crop residues, whereas in carrot and onion only about 30% of N was in crop residues. Nitrogen uptake from non-fertilized soil varied from 29 to 160 kg ha-1, depending on the growing season and the crop. Cabbage and carrot utilised soil N efficiently, usually taking up more than 100 kg ha-1 from non-fertilized soil. Onion, on the contrary, utilised soil N relatively poorly, usually less than 50 kg ha-1 from non-fertilized soil. The rate of N uptake was low with all crops in early summer. After one month, N uptake increased in cabbage and onion. This uptake continued until harvest, i.e. mid-August for onion and early September for cabbage. Nitrogen uptake by carrot started rapidly only two months after sowing and continued until harvest at the end of September. High N rates often resulted in high N concentrations and N uptakes, but growth was not necessarily increased. One month after fertilization, most of the N placed was still near the original fertilizer band and at the depth of 5-10 cm. At that time, broadcast N was at a depth of 0-5 cm. After harvest the soil mineral N content was generally low, i.e. below 25 kg ha-1 at the depth of 0-60 cm. Onion was an exception with poor growth in 1994, when soil mineral N after the highest N rate was 80 kg ha-1 at a depth of 0-60 cm after harvest. The placement distance in the cabbage experiment, 7.5 cm in the side and 7 cm below cabbage transplants, resulted in lower plant growth and N uptake than broadcasting of N at the beginning of the growing periods 1993 and Towards harvest differences between application methods decreased, although in 1993, placement of N still led to 6% lower cabbage yields than broadcasting of N. In 1993, high N rates increased cabbage dry weight and N uptake towards harvest, and this effect was more pronounced when N was broadcast. In 1994, soil N mineralisation was high, and only non-fertilized cabbages took up less N than fertilized plants. Carrot was remarkably insensitive to N fertilization. Carrot yields were similar with and without N fertilizers. Band placement and N rate did not affect carrot growth and N uptake. In 1993, band placement and high rates of N increased onion growth and bulb yield more than broadcasting. In 1994, onion growth was poor and treatments did not affect plant N concentrations or growth. Apparent recovery of fertilizer N was increased in 1993 by low N rates or band placement. This result that band placement of N does not much affect vegetable growth is in agreement with most previous studies. With onion, probably due to the sparse root system, positive effects of N placement are most likely to be found.
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9. Chinese Journal of Applied Ecology 2009, Vol. 20 Issue (03): 631-638
. Effects of different fertilization modes on vegetable growth, fertilizer nitrogen utilization, and nitrogen loss from vegetable field. HUANG Dong-feng;WANG Guo;LI Wei-hua; QIU Xiao-xuan
Chinese Journal of Applied Ecology  2009, Vol. 20 Issue (03):  
A field experiment with Chinese cabbage, water spinach, and three-colored amaranth cropped three times in one year was conducted to study the effects of seven fertilization modes, i.e., none fertilization, basal application of chemical fertilizers, 1/2 basal application and 1/2 top-dressing of chemical fertilizers, basal application of chemical fertilizers and dicyandiamide, 1/2 basal application and 1/2 top-dressing of chemical fertilizers and dicyandiamide, 1/2 basal application and 1/2 top-dressing of chemical fertilizers and organic manure, and basal application of organic manure, on the plant height, yield, nitrogen accumulation, and fertilizer nitrogen utilization of the vegetables, and the loss of NO3--N and NH4-N from vegetable field under natural rainfall condition.
The results showed that comparing with none fertilization, the fertilization modes ‘1/2 basal application and 1/2 top-dressing of chemical fertilizers and organic manure’ and ‘basal application of chemical fertilizers and dicyandiamide’ improved the agronomic properties of test vegetables, increased their yields by 103%〖KG-*2〗-〖KG-*7〗219% and 93%〖KG-*2〗-〖KG-*7〗226%, and nitrogen accumulation by 153%〖KG-*2〗-〖KG-*7〗216% and 231%〖KG-*2〗-〖KG-*7〗320%, respectively, and enhanced fertilizer nitrogen utilization rate.
They also decreased the surface runoff loss of NO3--N and NH4-N by 481% and 465%, respectively, compared with the mode ‘basal application of chemical fertilizers’, and hence, reduced the risk of agricultural non-point pollution. Therefore, these two fertilization modes could be popularized in vegetable production.
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10. Effects of nitrogen on development and growth of the leaves of vegetables. 3. Appearance and expansion growth of leaves of spinach
H. Biemond
NJAS Vol. 43 No
In a series of greenhouse and field trials, spinach cv. Trias plants were supplied with different amounts of N fertilizer in various split applications. Rates of leaf emergence and expansion were recorded, as well as final leaf size.
The rate of leaf appearance varied between 0.16 and 0.57/day across experiments, but was hardly affected by N treatment. The rate of leaf expansion and mature leaf area increased with leaf number, reaching maximum values at leaf pair 3+4 or 5+6 and decreasing subsequently. Both characteristics were positively correlated with N supply. The duration of expansion was not influenced by N treatments and varied between 15 and 30 days in most experiments.
The rate of leaf expansion was the main factor determining mature leaf size. Specific leaf area over all green leaves slowly decreased with time in most experiments and was around 300 cmsuperscript 2/g.
As the differences in the number of leaves were small, the differences in total green leaf area per plant resulted from differences in the areas of individual mature leaves.
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11. Authors: M.O. Abukutsa-Onyango, J. Karimi
. ISHS Acta Horticulturae 745: VI International Solanaceae Conference : Genomics Meets Biodiversity EFFECTS OF NITROGEN LEVELS ON GROWTH AND YIELD OF BROAD-LEAFED AFRICAN NIGHTSHADE (SOLANUM SCABRUM)
Authors:   M.O. Abukutsa-Onyango, J. Karimi
African nightshade (Solanum scabrum) is an important indigenous vegetable in many African countries, yet factors affecting leaf yields have not been fully investigated. A market survey conducted in Kakamega Municipal market in Kenya revealed that broad-leafed African nightshade was among the preferred African vegetables in the region. Besides being rich in micronutrients, it has several medicinal properties and is less bitter than other vegetable nightshades. For the potential of this crop to be exploited, there is a need to look at factors that would contribute to optimal leaf yields. Nitrogen affects growth and development of many leafy vegetables through its effect on cell division and hence leaf expansion. Little work has been reported on nitrogen effects on this emerging crop. The objective of the study was therefore to investigate effects of nitrogen rates on growth and yield of Solanum scabrum. A pot and two field experiments were conducted at Maseno University, Western Kenya, between June 2003 and December The pot experiment was laid out in a completely randomized design with four treatments and four replications.
The treatments included 0, 25, 50, and 75 mg of N per kg. The field experiments were set up in a randomized complete block design with six nitrogen rates and three replications. The treatments included 0, 10, 20, 40, 80 and 100 kg of N per hectare.
Nitrogen levels significantly (p ≤ 0.05) affected plant growth and leaf yields in both pot and field experiments with optimal levels at 25 mg N/kg and 40 kg N/ha respectively.
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12. Jean Masson, Nicolas Tremblay1 and André Gosselin
Effects of Nitrogen Fertilization and HPS Supplementary Lighting on Vegetable Transplant Production. II. Yield
Jean Masson, Nicolas Tremblay1 and André Gosselin
JASHS July 1991 vol. 116 no
Transplants of celery (Apium graveolens L.), lettuce (Lactuca sativa L.), broccoli (Brassica oleracea italica L.), and tomato (Lycopersicon esculentum Mill.) grown in multicellular trays under natural light or with supplementary lighting of 100 μmol·s-1·m-2 (PAR) in factorial combination with four rates of N fertilization (100, 200, 300, and 400 mg•liter-1) were tested for productivity under field conditions.
Celery was seeded once, lettuce twice, and broccoli and tomato three times. Broccoli and tomato were transplanted at two sites, celery and lettuce at one.
Supplementary lighting had no effect on yields of celery, lettuce, and broccoli, but significantly increased yields of early seeded tomato.
High rates of N fertilization (300 and 400 mg·liter-1) applied at the transplant stage improved yields for all the species.
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13. LIGHT AND NITROGEN LEVELS AFFECT THE AGRONOMIC PERFORMANCE OF VEGETABLE AMARANTH
D. J. Makus
HortScience May 1993 vol. 28 no
Three-week-old transplants of Amaranthus tricolor cultivars `RRC 241' and `Hinn Choy' were given split applications of supplemental N (0, 100 and 200 kg/ha). Five weeks after sowing both cvs. were exposed to 100, 70 and 50% of ambient solar radiation for nine and ten days, respectively.
During shading, avg. daily photosynthetic irradiance was reduced from 11.6 to 7.7 and 5.0 KW/m2, respectively. Soil, air, and leaf temperatures were reduced by shading. Plants were harvested in the seventh week.
Cultivars differed in leaf number and area, yield, height, mineral uptake, and stem fresh and dry weight. Increasing shade levels decreased the dry wt. of stems, leaf blades, and plants.
Shading had no effect on leaf area, plant fresh wt. or yield, but increased stem length, plant water content and leaf blade pigments. Photosynthetic fixation rates were reduced by 50% shade.
Leaf blade protein and most leaf blade mineral nutrients, including nitrates, were increased by shading.
Nitrogen application increased stem length, stem, leaf blade and plant fresh and dry wt., leaf blade pigments and yield.
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14. Effects of nitrogen on accumulation and partitioning of dry matter and nitrogen of vegetables. 2. Leek
H. Biemond
NJAS Vol No
Two greenhouse and 2 field trials were carried out on leeks cv. Albana with different N fertilizer rates and application dates. Observations included frequent measurements of DM and N accumulation in leaf blades, leaf sheaths and, if present, scapes. Both the amount of N applied and the time of application affected the total accumulation of DM and N in the plant.
The relative partitioning rates of DM increase to the shaft were affected in such a way that the final harvest indices for DM (which ranged from 0.32 to 0.53) were significantly lower at higher N application rates.
The final harvest indices for N ( ) were not significantly affected by amount or timing of fertilizer applications.
The total N concentrations of leaf blades and leaf sheaths decreased with increasing leaf age. Average nitrate N concentrations over all plant parts were always below 40%.
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15. Effects of nitrogen on development and growth of the leaves of vegetables. 2. Appearance, expansion growth and life span of leaves of leek plants
H. Biemond
NJAS Vol. 43 No
In greenhouse pot experiments and field trials, leek cv. Albana plants were supplied with different amounts of N fertilizer at various growth stages. Leaf emergence, expansion, size and senescence were monitored.
The rate of leaf appearance was not affected by N treatments and almost constant across experiments at 0.15/day. The rate of leaf expansion and the mature leaf area increased with leaf number, reaching maximum values between leaf numbers 11 and 14 and decreasing with higher leaf numbers. Both variables increased with increasing N application rate.
The duration of leaf expansion was more or less constant across leaf numbers and not influenced by N treatments; the leaf expansion rate was the main factor determining mature leaf area.
The rate of leaf senescence was not influenced by N treatments. Differences in total green leaf area per plant were caused by differences in the area of individual mature leaves and not by differences in the number of leaves. The specific leaf area of all leaves was more or less constant at 100 cmsuperscript 2/g.
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16. EFFECT OF NITROGEN ON GROWTH AND YIELD OF RADISH
Muhammad Saleem Jilani, Tariq Burki and Kashif Waseem*
J. Agric. Res., 2010, 48(2)
Effect of different levels of nitrogen on growth and yield of radish was studied at Gomal University, D. I. Khan, Pakistan during winter season 2007.
Five N levels (50, 100, 150, 200 and 250 kg/ha) alongwith a control (no nitrogen) were tried. The results showed that higher N levels gave better results for all parameters studied.
Maximum number of leaves (18.70, and 18.10), leaf length (33.33, and cm), weight of leaves (160.67, and g), root length (23.77, and cm), root diameter (4.43, 4.87 and 4.15 cm), root weight (139.28, and g) and yield (99.88, and t/ha) were recorded when N was 200, 250 and 150 kg per hectare, respectively.
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17. H. Biemond, J. Vos, P.C. Struik
Effects of nitrogen on development and growth of the leaves of vegetables. 1. Appearance, expansion growth and life span of leaves of Brussels sprouts plants
H. Biemond, J. Vos, P.C. Struik
NJAS Vol. 43 No
n greenhouse pot trials, Brussels sprouts cv. Icarus SG2004 plants were supplied with various amounts of N at different stages during growth.
The rate of leaf emergence ranged from 0.39 to 0.72 per day and was significantly increased by increasing N application rate. Leaf expansion rate and mature leaf area increased with leaf number, reaching maximum values between leaf number 10 and 20 and decreasing subsequently.
Plants receiving more N had a higher total green leaf area per plant, due to more and larger green leaves.
Specific leaf area of all leaves declined gradually from cmsuperscript 2/g (depending on experiment) at about 30 days after planting to 60 cmsuperscript 2/g at the end of the experiments and was usually significantly increased by increasing N application rate.
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18. . ISHS Acta Horticulturae 506: International Workshop on Ecological Aspects of Vegetable Fertilization in Integrated Crop Production NITROGEN EFFECTS ON VEGETABLE CROP PRODUCTION AND CHEMICAL COMPOSITION
Author:   J. Sorensen
Concerns about human health in relation to the intake of food have led to an increasing interest in the nutritional quality of food products. A high intake of vitamins, dietary fibres and some minerals, and a low intake of nitrate, is supposed to protect against several life-style diseases which occur in many industrialized countries.
Application of fertilizers may not only influence the yield and quality of field vegetable crops, but also the chemical composition of the marketable product. Therefore, application of fertilizers may be used to control and improve the nutritional quality of products used for human consumption. During the last two decades the chemical composition of field vegetable crops has been monitored in several fertilizer experiments at the Danish Institute of Agricultural Sciences.
This paper shows that increased N supply decreased the concentration of dry matter, potassium, sucrose, vitamin C, and dietary fibre in leaf vegetable crops, but increased the concentration of nitrate, nitrogen, and carotene.
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19. African Journal of Biotechnology Vol. 10 (48), pp
. African Journal of Biotechnology Vol.10 (48), pp , 29 August, 2011
The effects of applied nitrogen fertilizer and leaf positions on levels of micronutrients, anti-nutrients and toxic substances in Amaranthus cruentus
Amanabo Musa, Johnson A. Oladiran, Matthew I.S. Ezenwa, Helmina O. Akanya and Emmanuel O. Ogbadoyi
The presence of antinutrients and toxic substances in vegetables limits the nutritional benefits of vegetables. The effects of age of plant and application of nitrogen fertilizer on the bioaccumulation of antinutrients (oxalate), toxic substances (cyanide and nitrate), micronutrients (vitamin C, β-carotene -provitamin A) and mineral elements (Fe, Mg, Cu, Zn, Ca Na and K) in Amaranthus cruentus were investigated using pot experiment. Leaves were harvested at market maturity (vegetative phase) at three different leaf positions, basal (oldest), middle (younger) and upper (youngest) and were subjected to chemical analysis.
Results obtained showed that cyanide, nitrate and oxalate were concentrated significantly in the basal and middle positions. The concentration of β-carotene, vitamin C and Zn were significantly higher in the leaves in the middle part than in the basal and upper leaves. Similarly, Fe, Mg, Cu and Na contents were significantly higher in the basal leaves than in the middle and upper leaves, while the concentration of K was higher in the younger leaves.
We concluded that consumption of the vegetable leaves from the upper leaf position will provide the dietary requirements of the analysed micronutrients with significant reduction in the levels of oxalate, cyanide and nitrate and associated health problems.
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20. Diunduh dari: http://scialert.net/abstract/?doi=pjn.2010.1039.1042..
. Pakistan Journal of Nutrition   Year: 2010 | Volume: 9 | Issue: 11 | Page No.: Effects of Effective Microorganisms on Yield and Quality of Vegetable Cabbage Comparatively to Nitrogen and Phosphorus Fertilizers Kwizera Chantal, Shao Xiaohou, Wang Weimu and Basil T. Iro Ong`or
The misuse and excessive use of fertilizers resulted in the loss of soil sustainability and a declined productivity, have increased the need of use of Effective Microorganisms Technology (EM) as an alternative to such practices to meet the future nutritional requirements of the people.
This study aimed at appraising the effects of EM on Leaf Area (LA) and Photosynthesis (PH) of vegetable cabbage comparatively to Nitrogen (N) and Phosphorus (P) fertilizers. Results showed an increased leaf area for treatments with EM, while others demonstrated its reduction.
Significant among treatments was recorded with p<0.05. Likewise, EM has improved photosynthesis. This suggested that EM improve plant yield and quality, resulting in a fulfillment of a sustainable agriculture.
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21. Diunduh dari: http://www.jhortscib.org/Vol75/75_6/1.htm..
.   The Journal of Horticultural Science & Biotechnology November 2000 — Vol. 75 No: 6
Changes in chlorophyll, ribulose bisphosphate carboxylase-oxygenase, glycine betaine content, photosynthesis and transpiration in Amaranthus tricolor leaves during salt stress
Y. WANG and N. NII
pp:
We examined changes in leaf growth and chemical composition, including chlorophyll content, ribulose bisphosphate carboxylase-oxygenase (RuBisCO), and glycine betaine (GB) in relation to photosynthesis and transpiration responses to salt stress in Amaranthus tricolor leaves. To induce salt stress, plants were transferred to a growth medium containing 300 mM NaCl for 7 d followed by 7 d of relief from salinity. A decrease in leaf enlargement began 3 d after salt stress, and leaves subsequently showed the same degree of regrowth as controls after relief in non-salt medium.
Chlorophyll content expressed on a leaf-area basis increased under conditions of salinity due to a reduction in leaf tissue water content. The decrease in chlorophyll content continued throughout the 7 d of relief from salinity. The RuBisCO and soluble protein contents when expressed on a leaf dry-weight basis decreased in response to salinity, and then gradually increased during the relief period. GB content increased slightly up to 3 d of salt stress, and showed typical accumulation during salt stress.
GB content decreased sharply immediately after plants were transferred to non-stress medium, but remained at a higher level throughout the relief period. A decrease in photosynthetic activity and transpiration rate preceded any changes in leaf area, RuBisCO or GB content. During relief from salinity, photosynthesis and transpiration rates gradually recovered to control levels with restoration of stomatal conductance.
The above findings suggest that the increase in GB content is important in adaptation to salt stress in Amaranthus plants, although photosynthesis and transpiration responses occurred immediately after salt-stress.
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22. Diunduh dari: http://www.jhortscib.org/Vol75/75_6/index.htm..
Alleviating phosphorus stress of chile ancho pepper (Capsicum annuum L. 'San Luis') by arbuscular mycorrhizal inoculation
F.T. DAVIES, JR, V. OLALDE-PORTUGAL, M.J. ALVARADO, H.M. ESCAMILLA, R.C. FERRERA-CERRATO and J.I. ESPINOSA
The Journal of Horticultural Science & Biotechnology November 2000 — Vol. 75 No: 6 . pp:
Chile ancho pepper (Capsicum annuum L. 'San Luis') is a primary source of vitamin C in the Mexican diet. It is important to select indigenous mycorrhizal fungi from Mexico that will utilize nutrients and water more efficiently in the production of this commercially valuable, native crop. In a greenhouse study, Chile ancho pepper plants were either non-inoculated (NonAMF), or inoculated with arbuscular mycorrhiza (AMF): Glomus fasciculatum, or a mixed species inoculum from Mexico (ZAC-19) containing Glomus albidum, Glomus claroides and Glomus diaphanum.
Under reduced phosphorus (P) conditions, AMF enhanced plant vegetative and reproductive growth. Growth of AMF plants at low P was comparable with NonAMF plants at moderate P. At low P, only plants inoculated with ZAC-19 had greater leaf tissue P than NonAMF plants, while both groups of inoculated plants had greater leaf tissue P at moderate P fertility.
AMF plants generally had greater Fe, Mn, Zn and Cu, but lower N and K (ZAC-19) than NonAMF chile ancho plants. Formation of extraradical hyphae was greatest in ZAC-19 at low P, and was reduced at higher P levels. This corresponded with a 2.9 fold reduction in spores recoverable in soil by ZAC-19 at high P; however spore production and development of extraradical hyphae by Glomus fasciculatum was not affected by P fertility.
At low P, G. fasciculatum had greater arbuscule and vesicle formation than ZAC-19. While both AMF isolates enhanced vegetative and reproductive growth of chile ancho under reduced P conditions, G. fasciculatum was generally more effective than ZAC-1.
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23. The effect of nitrogen application on nitrogen utilization by white cabbage (Brassica oleracea var. capitata) and on nitrogen in the soil at harvest
A.P. EVERAARTS and R. BOOIJ
The Journal of Horticultural Science & Biotechnology November 2000 — Vol. 75 No: 6 pp:
During two seasons and at four locations the effect of the rate of nitrogen application and the method of application on the nitrogen uptake by white cabbage (Brassica oleracea var. capitata) was studied. Maximum nitrogen uptake by white cabbage was around 400 kg ha-1. Split application had no effect on nitrogen uptake. Band placement incidentally stimulated nitrogen uptake by the crop.
The efficiency of nitrogen utilization for product dry-matter production decreased with increasing nitrogen rates. With increasing amounts of nitrogen applied the dry matter concentration of the heads decreased linearly with increasing nitrogen concentration. The nitrogen harvest index, the amount of nitrogen removed from the field with the product as a percentage of the total uptake by the crop at harvest, was not influenced by the rate or method of nitrogen application and varied between experiments from 54 to 60%. The amount of nitrogen in crop residues increased with increasing amounts of nitrogen applied and, in two experiments, was higher with band placement of nitrogen.
At the optimum nitrogen application rate (= Nmin 0-60 cm kg ha-1; Everaarts and De Moel, 1998) an average of 113 kg of nitrogen ha-1 would have been left in the field in crop residues at harvest. The amount of nitrogen left in the soil at harvest was low and amounted to a maximum of around 40 kg ha-1 for the soil layer 0-90 cm. Leaching of nitrogen during growth is probably limited. High amounts of nitrogen band placed resulted in a horizontally unequal distribution of soil nitrogen at harvest.
The amount of nitrogen unaccounted for at harvest was proportional to the amount of nitrogen available and for all experiments could be described by one linear equation. The method of fertilizer application had no effect on this relationship. The amount of nitrogen in crop residues is the largest single source of potential loss of nitrogen with white cabbage cultivation.
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24. The Journal of Horticultural Science & Biotechnology Vol. 75 No: 6
Effect of humidity and nutrient feed K/Ca ratio on physiological responses and the accumulation of dry matter, Ca and K in tomato B.J. MULHOLLAND, M. FUSSELL, R.N. EDMONDSON, I.G. BURNS, J.M.T. McKEE and J. BASHAM pp:
Two levels of humidity, high, 0.1 kPa vapour pressure deficit (vpd) and control 0.5 kPa vpd, and four nutrient feed K/Ca mM ratios (4/7, 10/7, 4/2 and 10/2) were applied in all factorial combinations to a nine-week old tomato (Lycopersicon esculentum Mill.) crop for 63 d.
The effect on gas exchange, water relations, vegetative growth, yield and accumulation of Ca and K in the shoot was examined. High humidity had a deleterious effect on leaf expansion, delayed truss and fruit maturity and reduced fruit yield. Water uptake was reduced and the Ca concentration of leaf and fruit tissue was increased under high humidity compared with plants grown under control humidity; K accumulation was unaffected.
The accumulation of K and Ca in the shoot appeared to be poorly related to the rate of transpiration. The high (10/2 mM) K/Ca ratio nutrient feed had little effect on vegetative growth and yield compared with the low (4/7 mM), but restricted Ca uptake to the fruits at both the high and the control humidity. During the measurement period, hours, stomatal conductance and leaf water status remained high at elevated humidity, compared with a progressive reduction in leaf water status and low stomatal conductance in the control humidity.
A/ci gas exchange analysis where A is the net CO2 assimilation rate and ci is the intercellular partial pressure of CO2 suggested that, at high humidity, the photosynthetic capacity of the leaves was reduced because of a lower in vivo carboxylation efficiency. However, the mechanism(s) responsible for reduced leaf expansion remains unclear.
The complex interrelations between physiological responses, leaf expansion and the uptake and distribution of K and Ca to the shoot, are discussed.
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25. The Journal of Horticultural Science & Biotechnology Vol. 75 No: 6
Apparent nitrogen mineralization and recovery of nitrogen supply in field trials with vegetable crops M FINK and H.C. SCHARPF pp:
A major cause of uncertainty in predicting the demand of nitrogen (N) fertilizer by means of mathematical models is the treatment of apparent net N mineralization (ANM) and apparent recovery rate (REC) of mineral N supply (N fertilizer plus soil mineral N at planting). REC and ANM were analysed in 29 multi-level N fertilizer trials conducted with a range of vegetable crops over a period of 11 years.
REC differed substantially between experiments (0.29 to 1.24). ANM ranged from -110 to 140 kg N ha-1; it decreased with an increasing N supply, and increased with the time between planting and harvest.
A simple regression model was used to predict ANM. The model consisted of both a N supply-dependent and supply-independent term, and used N supply and growing time as input parameters. Whereas the model significantly reduced the variance in measured ANM (r2 = 0.45, n = 129), the residuals showed a considerable variation (standard deviation (SD) = 37 kg N ha-1).
It is not feasible to predict N fertilizer demand without predicting net N mineralization and fertilizer recovery. Therefore, the regression model is recommended despite its inaccuracy, which is taken into account by adding a security margin to the fertilizer recommendation.
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26. Agron. Sustain. Dev. 30 (2010) 763–768Research article
Efficient urea-N and KNO3-N uptake by vegetable plants using fertigation
Constantinos Ehaliotis, Ioannis Massas and Georgios Pavlou
Vegetable production demands high nitrogen inputs. Fertigation is a means to increase fertilizer-N use by plants. However, the effect of different N sources and doses, and how they relate to the total available N in soils are poorly known.
In this study we applied 15N-labeled fertilizers to green pepper in the field using a drip irrigation system during the dry summer. KNO3-N and urea-N were applied at a total of 6, 12 and 18 g plant−1. Our results show that urea was as effective as KNO3 as a N source.
The fertilizer-N utilization efficiency was dramatically reduced at higher N doses, from 48% for the 6 g N plant−1 dose to 36% and 26% for the 12 and 18 g N plant−1 doses, respectively. However, the N in plants derived from fertilizer consistently exceeded 60%, indicating high availability of fertilizer-N even at the lowest dose. Negative added nitrogen interactions – the effect of added N on the fate of soil-N – were observed, particularly at high fertilizer-N doses. The fertilizer-N utilization efficiency calculated by the difference method was lower compared with the 15N enrichment method.
This clearly indicates luxury N applications and excess N availability brought about by precise localized placement of fertilizer-N that leads to limited uptake of the available soil-N. N leaching risks in the following rain period should therefore be based on both the residual fertilizer-N and the increased amounts of residual soil mineral-N.
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27. Soil Use and Management
Effects of vertical distribution of soil inorganic nitrogen on root growth and subsequent nitrogen uptake by field vegetable crops
H. L. Kristensen, K. Thorup-Kristensen
Soil Use and Management
Volume 23, Issue 4, pages 338–347, December 2007
Information is needed about root growth and N uptake of crops under different soil conditions to increase nitrogen use efficiency in horticultural production. The purpose of this study was to investigate if differences in vertical distribution of soil nitrogen (Ninorg) affected root growth and N uptake of a variety of horticultural crops. Two field experiments were performed each over 2 years with shallow or deep placement of soil Ninorg obtained by management of cover crops. Vegetable crops of leek, potato, Chinese cabbage, beetroot, summer squash and white cabbage reached root depths of 0.5, 0.7, 1.3, 1.9, 1.9 and more than 2.4 m, respectively, at harvest, and showed rates of root depth penetration from 0.2 to 1.5 mm day−1 °C−1. Shallow placement of soil Ninorg resulted in greater N uptake in the shallow-rooted leek and potato. Deep placement of soil Ninorg resulted in greater rates of root depth penetration in the deep-rooted Chinese cabbage, summer squash and white cabbage, which increased their depth by 0.2–0.4 m.
The root frequency was decreased in shallow soil layers (white cabbage) and increased in deep soil layers (Chinese cabbage, summer squash and white cabbage). The influence of vertical distribution of soil Ninorg on root distribution and capacity for depletion of soil Ninorg was much less than the effect of inherent differences between species. Thus, knowledge about differences in root growth between species should be used when designing crop rotations with high N use efficiency.
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28. Authors: T. Lošák, J. Hlušek, S. Kráčmar, Mårtensson
. ISHS Acta Horticulturae 852: IV International Symposium on Ecologically Sound Fertilization Strategies for Field Vegetable Production EFFECT OF NITROGEN AND SULPHUR FERTILISATION ON YIELDS, NITRATES AND CYSTEINE AND METHIONINE CONTENT IN ONION (ALLIUM CEPA L.)
Authors:   T. Lošák, J. Hlušek, S. Kráčmar, Mårtensson
This study explored the interactive effects of two doses of nitrogen and two levels of soil sulphur on onion yields, nitrate content and concentration of the amino acids cysteine and methionine under accurately controlled conditions. Onions were cultivated in Mitscherlich pots with 6 kg of soil with a low content of S-SO42- (5 ppm, S0) or a high content (30 ppm, S1) with added doses of 0.6 (N1) and 1.2 (N2) g N pot-1 as (NH4) 2SO4 and NH4NO3.
There were no significant differences (P<0.05) in onion yields between the two N doses. The higher sulphur content (S1) increased yields by % compared with S0 for both doses of nitrogen. The nitrate content in fresh onion increased with nitrogen dose (225 and 566 mg NO3- kg-1 for N1 and N2 respectively).
High sulphur reduced the nitrate content of onions by % depending on nitrogen dose. The contents of cysteine and methionine increased by on average 39.1% and 25%, respectively, with increasing nitrogen dose. Soil sulphur content did not change the cysteine content but higher sulphur content in combination with higher nitrogen dose (N2) significantly increased the methionine content, by % compared with the other treatments. Joint fertilisation with nitrogen and sulphur is thus a suitable measure to increase onion yield and quality since it stabilises or increases the content of sulphur amino acids and reduces the level of undesirable nitrates.
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29. EFFECT OF NITROGEN SOURCE AND LEVEL ON VEGETABLE AMARANTH
D. J. Makus
HortScience May 1994 vol. 29 no
On 3 Aug. 1993, 20-day-old `Hinn Choy' plants (Amaranthus tricolor L.) were-planted on 15 × 15 cm spacings in 4-row beds at 1.3 m row spacings in a Leadvale silt loam soil. Nitrogen sources of NH4, NO3 and NH4 NO3 were used at rates of 0, 100 and 200 kg/ha, and were split-applied at and 1 week after transplanting. All treatments received both supplemental K and P at the rate of 90 kg/ha at planting.
Plants were harvested 31 days after transplanting. Plants given the NH, source were taller, and were higher in yield, leaf chlorophyll, total carotenoids and Mn (dry wt basis) than were plants given other N-sources. NO3-N fertilizer increased leaf Fe and Cu, and residual soil K and NO3, but reduced Mn levels.
Leaf blade Ca was highest when NH4NO3 fertilizer was used. Increasing N-rates decreased both soil pH linearly and leaf blade Ca but linearly increased soil EC, NO3, and S and leaf blade N, K, S, P, NO3, Fe, chlorophyll and carotenoids.
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30. The effect of nitrogen and the method of application on
yield and quality of broccoli
A.P. EVERAARTS1,* AND P. DE WILLIGEN2
Netherlands Journal of Agricultural Science 47 (1999)
The effects of the amount and the method of nitrogen application on yield and quality of broccoli were studied during three seasons. Different amounts of nitrogen fertilizer were applied broadcast or band placed at planting. Band placement of fertilizer increased the yield in five out of eight experiments.
Application of nitrogen results in larger heads. No relationship was found between mineral nitrogen at planting and optimum nitrogen applications because of the narrow range of amounts of mineral nitrogen at planting.
Split application had no or a negative effect on yield and therefore is not recommended. For optimum yields it is recommended to apply 270 kg of nitrogen per hectare, minus the mineral nitrogen in the soil layer 0–60 cm at planting, band placed at planting.
For broadcast application 275 kg of nitrogen minus mineral nitrogen applied at planting is recommended, but yield will be lower as compared with band placement of fertilizer.
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31. Effect of Different Levels of Nitrogen Fertilizer and Cultivars
Middle Eastern and Russian Journal of Plant Science and Biotechnology ©2007 Global Science Books
Effect of Different Levels of Nitrogen Fertilizer and Cultivars
on Growth, Yield and Yield Components of
Romaine Lettuce (Lactuca sativa L.)
Maryam Boroujerdnia* • Naser Alemzadeh Ansari
Middle Eastern and Russian Journal of Plant Science and Biotechnology 1(2), ©2007 Global Science Books
In order to determine the effect of nitrogen fertilizer rates and cultivars on growth and critical yield of lettuce, an experiment was
conducted at Shahid Chamran University of Ahwaz, Iran during This study was arranged in a spilt plot experiment based on a
randomized complete block design, in three replications. The treatments included four nitrogen rates (0, 60, 120, and 180 kg N ha-1) as the
main plot and two lettuce cultivars (‘Pich Ahwazi’ and ‘Pich Varamini’) as the sub-plot. Sampling was done in 86, 100, 114, 126, 142, and
156 days after sowing. The criteria measured were plant length, fresh and dry weights of leaves, leaf area, number of leaves, crop growth
rate (CGR), leaf area index (LAI) and yield. Results indicated that different levels of nitrogen fertilizer on all growth characteristics were
significant at P<0.01. Nitrogen fertilizer caused head formation to accelerate and delayed the bolting date of lettuce. Cultivar had a
significant effect on growth characteristics, on fresh and dry weights of leaves and on leaf number but not on plant length and leaf area.
The highest yield was obtained with 120 kg ha-1 treatment by ‘Pich Ahwazi’. Also, it took ‘Pich Varamini’ longer to form a head and to
flower than ‘Pich Ahwazi’.
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32. Diunduh dari: . http://aob.oxfordjournals.org/content/51/4/429.short.
Effects of Photoperiod, Nitrogen Nutrition and Temperature on Inflorescence Initiation and Development in Onion (Allium cepa L.)
J. L. BREWSTER
Ann Bot (1983) 51 (4):
The effects of photoperiod, nitrogen nutrition and temperature on inflorescence initiation and development in onion cv. Rijnsburger and cv. Senshyu Semi-globe Yellow were studied in controlled environments.
Rates of inflorescence initiation were estimated using the data for leaf numbers formed prior to flower formation and the rates of leaf initiation. At 9 °C inflorescence initiation was accelerated by long photoperiods particularly for cv. Rijnsburger where the average time for initiation was 86 days in 8 h and 38 days in 20 h photoperiods. Initiation was as rapid at 12 °C as at 9 °C but was slower at 6 °C.
A reduction in the nitrate concentration in the nutrient solution from to M greatly accelerated inflorescence initiation particularly in photoperiods and temperatures not conducive to rapid initiation. Cv. Senshyu initiated more slowly than cv. Rijnsburger and was less sensitive to photoperiod and nitrogen level.
The development rate of inflorescences after initiation was accelerated by long photoperiods and increases in temperature from 6 to 12 °C but was retarded by the lower nitrogen level.
Diunduh dari: .

33. Authors: L. Nett, C. Feller, M. Fink
. ISHS Acta Horticulturae 852: IV International Symposium on Ecologically Sound Fertilization Strategies for Field Vegetable Production IDENTIFICATION OF CROP ROTATIONS INCLUDING NITROGEN CATCH CROPS WHICH CAN DECREASE NITROGEN LOSSES IN GERMAN FIELD VEGETABLE PRODUCTION SYSTEMS
Authors:   L. Nett, C. Feller, M. Fink
Nitrogen (N) use efficiency in field vegetable production systems has to be increased in order to avoid negative environmental impacts, meet legal regulations and guarantee the farmers’ competitiveness.
The use of catch crops has been shown to have a great potential in reducing N losses by retaining N in the plant-soil system. However, the effects of catch crops on the N nutrition of the succeeding crop vary from positive to negative and numerous possible combinations exist of different crop rotations, management practices and soil and weather conditions.
To find appropriate crop rotations for every individual location by means of field trials is too time-consuming, laborious and costly. A modelling approach was therefore adopted using the DAISY model which was validated with data from a field experiment. The results of the crop rotation experiment in the field (main crop–catch crop–successive crop) indicated that N recovery at harvest of the successive crop in aboveground plant biomass and soil mineral N (Nmin) ranged between 42% and 84% of the N input at harvest of the main crop in crop residues and Nmin. As compared to fallow, the catch crop had a small positive effect on N recovery (64% vs. 49%) in one out of four cases and negative effects in all other cases. The agreement between simulated and measured plant dry masses was good with an R2 (linear regression) for all dry mass data pooled of 0.83 (n=48) whereas there were still systematic deviations for Nmin and plant N uptake.
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34. Abdur Razzaq, M. Munir, N.I. Hashmi*, P.R. Hobbs ** and A. Majid
. CURRENT MANAGEMENT PRACTICES FOR WHEAT PRODUCTION IN A RAINFED AGRO-ECOLOGICAL ZONE IN NORTHERN PUNJAB
  Abdur Razzaq, M. Munir, N.I. Hashmi*, P.R. Hobbs ** and A. Majid
Pakistan Journal of Agricultural Research, Vol, 17 No. 3
This study is based on the surveys undertaken during wheat har­vest in the rainfed areas of Rawalpindi District of northern Punjab. Wheat yields were estimated by crop cut and data regarding management practices adopted by farmers for wheat in the same plots was collected. Eighty nine percent of the sample farmers were owner operators, only 11% tenants.
Land type was classified as lepara land, near the homestead which receives farm yard manure and mera land further from the village. The most common cropping system is called Dosala where wheat and kharlf crops are grown in one year followed by the same land remaining fallow for the next whole year.
On lepara land, double cropping every year was practiced on 46% of the sample fields. The average number of ploughings was 8.2 and varied from 1 to 20.
There was a significant increase in the use of tractor ploughing in the 4 years of study from 35% to 70%. The average harvest date varied from April 15 to May V depending on temperature which was influenced by rainfall. Planting by drill on contract has risen from 20% in 1983 to 59% in 1986 replacing the pora method. About 7% of the farmer prefer the high quality variety C-591. Lyp-73 was the most popular variety but this is being replaced with the new variety Pak-81. Pak-81 increased from 26% to 55% during the study period at the expense of Lyp­73. The average yield of wheat was 1.98 t/ha.
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35. Producing Nitrate-free Endive Heads: Effect of Nitrogen Form on Growth, Yield, and Ion Composition of Endive
Pietro Santamaria
Antonio Elia
JASHS January 1997 vol. 122 no
In a growth chamber, endive (Cichorium endivia L. var. crispum Hegi) plants were grown using a solution culture method to evaluate the influence of four ammonium : nitrate (NH4-N : NO3-N) percentage ratios (100:0, 70:30, 30:70, and 0:100) on growth (leaf area, dry mass, crop growth rate, relative growth rate, and net assimilation rate), yield characteristics (head and root fresh mass and root length), quality (dry matter, nitrogen, and nitrate), and inorganic ion content.
No symptoms of NH4+ toxicity were detected in endive plants 8 weeks after beginning nutrient treatments. Moreover, by feeding N in mixed form, the growth indices increased compared to indices from feeding with any of the two N forms alone. Ammonium-fed plants produced nitrate-free heads with a fresh mass (171 g) similar to nitrate-fed plants. Compared to the other treatments, the heads of NH4+-fed plants were darker green and more succulent.
Mixed N improved yield but caused a remarkable accumulation of nitrate in heads. Following an increase in NO3-N from 30% to 70% in the nutrient solution, head fresh mass rose from 196 to 231 g and NO3- concentration more than doubled (from 2.4 to 6.1 g·kg-1 fresh mass). With 100% of NO3-N, NO3- concentration was 5.5 g·kg-1 fresh mass. With higher NO3-N percentages in the nutrient solution, the difference in the concentration of inorganic cations and anions increased, but K+ concentration was also high in ammonium-fed plants (on average 77 g·kg-1 dry mass).
Head total N accumulation was increased by the presence of NH4+ in the nutrient solution and decreased with 100% NO3-N. From the commercial viewpoint, the produce obtained from 100% NH4-N was good, with the value-added factor of the absence of nitrate.
This may be an extremely remarkable factor because of the commercial limits on the allowable nitrate content in leafy vegetables already enforced by many European countries and those the European Union is going to adopt in a directive.
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36. Yield response of African leafy vegetables to nitrogen,
phosphorus and potassium: The case of Brassica rapa L.
subsp. chinensis and Solanum retroflexum Dun.#
W van Averbeke*, KA Juma and TE Tshikalange
Water SA Vol. 33 No. 3 (Special Edition) 2007
In this study the growth and yield response of Solanum retroflexum Dun. (nightshade) and Brassica rapa L. subsp. chinensis
(non-heading Chinese cabbage) to N, P and K availability in the soil and the interaction effects of these three nutrients were
determined by means of pot experiments in a greenhouse.
S. retroflexum was most sensitive to the availability of nitrogen
in the soil. Sufficient nitrogen needed to be available to achieve optimum growth but adding too much adversely affected
biomass production, suggesting a fairly narrow optimum range for nitrogen availability.
The production of the crop was also
dependent on the adequate availability of phosphorus and potassium but any adverse effects due to excess availability were
less distinct than for nitrogen. In the case of B. rapa subsp. chinensis, an optimum availability range was identified for N and
K and a critical level of availability for P.
The decline in biomass production caused by adding N in excess of the optimum was reversed by applying both P and K at rates that were in excess of the respective optima.
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37. EFFECTS OF NITROGEN FORMS ON THE GROWTH AND POLYAMINE CONTENTS IN DEVELOPING SEEDS OF VEGETABLE SOYBEAN
Authors: Chen, Lei; Liu, Qian-Qian; Gai, Jun-Yi; Zhu, Yue-Lin; Yang, Li-Fei; Wang, Cong
Source: Journal of Plant Nutrition, Volume 34, Number 4, January 2011 , pp (18)
A pot culture experiment of nitrogen forms [nitrate (NO-3): ammonium (NH+4)] with four ratios (100:0, 75:25, 50:50, and 25:75) in nutrient solutions was conducted to examine the effect of nitrogen forms on the growth and polyamine contents of developing seeds of vegetable soybean [Glycine max (L.) Merr. cv. 'Li-xiang 95-1'].
Results showed that the best plant growth vigor was observed in [image omitted] (75%), and then in [image omitted] (50%). However, the fresh and dry weight of biomass decreased when a high concentration of either [image omitted] (100%) or [image omitted] (75%) was the primary nitrogen source in the nutrient solution. The numbers of flowers and pods in [image omitted] (75%) were significantly decreased compared with other ammonium-nitrate ratios in which the numbers of flowers and pods were not influenced by nitrogen forms.
During the development of seeds, levels of free Put and Spd decreased, and the decrease extents were more marked in 100:0 and 25:75 ([image omitted]:[image omitted]), but the change of free Spm was opposite. Levels of conjugated and bound polyamines in all nitrogen forms increased, but the increases in 75:25 and 50:50 ([image omitted]:[image omitted]) were not so obvious as in 100:0 and 25:75 ([image omitted]:[image omitted]) treatments. The possible roles of polyamines in the adaptive mechanism of vegetable soybean seeds to different nitrogen forms were discussed.
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38. Authors: C.R. Gastaldi, B.G. Sutton
. ISHS Acta Horticulturae 247: Research and Development Conference on Vegetables, the Market and the Producer
OPTIMIZING NITROGEN FERTILIZATION OF VEGETABLE CROPS BY DRIP IRRIGATION
Authors:   C.R. Gastaldi, B.G. Sutton
. Nitrogen nutrition requirements of lettuce seedlings in recirculating solution culture were investigated.
The effects of different NH4-N/ NO3-N ratios on growth of the plants were measured. A growth technique, in which additions of nitrogen increase with time as a result of electrical conductivity and pH titrations was tested.
The results obtained showed that a stable internal nutrient status was achieved after 2 weeks. Linear regressions were found between accumulated nitrogen addition and growth, accumulated nitrogen addition and accumulated nitrogen uptake.
This information can be employed in establishing conditions for efficient use of N fertilizer in drip irrigation.
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39. E. Ryan Harrelson, Greg D. Hoyt1, John L. Havlin, David W. Monks
Effect of Planting Date and Nitrogen Fertilization Rates on No-till Pumpkins
E. Ryan Harrelson, Greg D. Hoyt1, John L. Havlin, David W. Monks
HortScience June 2008 vol. 43 no
. Vegetable growers in the Mountain region of North Carolina are faced with increased land prices resulting from urbanization and reduced farm income from low-commodity prices. Local consumer use of pumpkin (Cucurbita pepo) for jack-o-lanterns and baking provides a fall market for growers to increase production and profitability on-farm.
Most soils in these regions are highly erodible and susceptible to drought during the growing season. Little information is available on cultural practices for no-till pumpkin production in this region. Field studies were established to evaluate the yield response of no-till pumpkin to planting date and nitrogen (N) fertilization. Experiments were conducted at the Mountain (MRS), Upper Mountain (UMRS), and the Mountain Horticultural Crops Research Stations (MHCRS) in Summer 2003 and 2004 using no-till cultural practices.
Three planting dates were established at 2-week intervals and 0, 40, 80, and 120 kg·ha−1 N treatments were applied at each planting date in a randomized complete block design.
The 80 and 120 kg·ha−1 N fertilization rates produced greater yields and larger fruit size than the 0 and 40 kg·ha−1 N rates. Pumpkins planted earliest produced the greatest marketable and total yields for all N rates at all three locations. The latest planting date (9 July) and highest N rate yielded more cull fruit compared with marketable pumpkins with the earlier planting date at the Upper Mountain Research Station. This location has a shorter growing season and cooler summer temperatures than the two other locations. Although the third planting date was late for pumpkin planting, higher N rate treatments at that timing produced marketable yields comparable to earlier planting dates at the two warmer summer locations (MRS and MHCRS).
In these experiments, the highest rate applied (120 kg·ha−1 N) maximized pumpkin yield. This observation would indicate that higher yields might be possible with even greater N rates.
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40. for organic vegetable production
Nutrient management
for organic vegetable production

41. Average rates of N, P2O5 and K2O applied to vegetable crops in the US
(lbs/acre)
Nitrogen Phosphorus Potassium
Why are these rates so high ?

42. ~ 16 elements have been identified as essential for the growth of all plants
Soil
C O H
N K Ca Mg P S
Cl Fe Mn Zn B Cu Mo
air & water
macronutrients
micronutrients V Ni
Needed by some plants Si Co Na

43. Micronutrients are critical components of enzymes

44. Soil water contains nutrients
H20
H20 K+ -
H20 -
Ca+2 -
H20
H20 -
Mg+2 - H+
Humus -
H20
exchangeable
ions
H20
H20
H20
Soil
soup
Clay
H20 -
Na+
H20
H20 -
H20 -
H20 - K+
H20
Ca+2
H20
H20

45. Adapted from Brady and Weil (2002)
What’s in the soil soup ??
Ca+2
Cu+3
DOM
NO3-
Ca+2
Mg+2
NO3-
H2PO4-
Ca+2
Zn+2
DOM K+
NO3- K+
Mg+2
Ca+2
NO3-
Mg+2
Fe+3
DOM
Ca+2
SO4-2
Adapted from Brady and Weil (2002)

46. Which forms of nutrients are available to plants ?
solution
exchangeable
“active” OM
passive “OM”
weatherable minerals

47. Modified from Havlin et al. (1999)
Re-seasoning the soup
Modified from Havlin et al. (1999)

48. Nutrient availability……
Crop yield
Deficiency
Symptoms
Nutrient availability

49. http://www. extension. umn

51. Understanding nutrient uptake activate soil microbes
H20
Root exudates
activate soil microbes
Transpirational
stream
H20
Root growth

52. ? Feed the soil vs. Feed the crop ? Both strategies are important !
Healthy roots need available nutrients !
Unhealthy roots use nutrients inefficiently…
Acute root disease
Chronic root malfunction

53. Nutrient availability varies with pH

54. Understanding aluminum toxicity
Toxic forms of Al are bioavailable at low pHs
Aluminum toxicity is minimal above
pH 5.5

55. 100%
75%
50%
Percentage of maximum cation exchange capacity
25%
Exchangeable
Al+3 0%
Brady and Weil (2002)

57. Kodithuwakku, D. P.; Kirthisinghe, J. P.
. The effect of different rates of nitrogen fertilizer application on the growth, yield and postharvest life of cauliflower.
Kodithuwakku, D. P.; Kirthisinghe, J. P.
Journal Tropical Agricultural Research 2009 Vol. 21 No. 1 pp
A Field experiment was conducted to compare the effect of urea as a fertilizer on growth, yield and post harvest life of cauliflower (Brassica oleracea L). Four levels of urea were compared with the recommendation of the Department of Agriculture (DOA), using a Randomized Complete Block Design. Other cultural practices and crop protection were done according to the recommendations of the DOA.
The plant height at one week after transplanting and 50% flowering, number of leaves at 50% flowering, total leaf area at time of flowering, total number of days to flowering, and time period for curd maturity were recorded in each treatment. The average cauliflower curd yield in the field varied between g/plant ( t/ha). The results revealed the possibility of increasing N dosage up to 125% of the DOA recommendation for obtaining larger curds and a higher curd yield.
Significant difference was not observed (p>0.05) among the treatments in any of the curd quality parameters measured. Even though no significant difference was observed among the post harvest quality, curds of the 50% nitrogen fertilizer treatment stored at room condition and in polythene bags could be kept 6 days & 9 days longer than other treatments, without decay.
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58. HortTechnology February 2012 vol. 22 no. 1 37-43
Estimating Nitrogen Mineralization of Composted Poultry Manure, Organic Fertilizers, and Green Manure Crops for Organic Sweet Corn Production on a Sandy Soil Under Laboratory Conditions
Heidi J. Johnson, Jed B. Colquhoun, Alvin J. Bussan1 and Carrie A.M. Laboski
HortTechnology February 2012 vol. 22 no
Organic sweet corn (Zea mays) production is challenging for growers because of the high nitrogen (N) requirements of sweet corn and the relatively low N content of organic soil amendments.
Total N supplied and rate of mineralization throughout the growing season are two important aspects in determining the optimal N management program. Green manure (GrM) crops, composted manures, and commercially available organic fertilizers are used to manage N in organic production systems. Using a combination of these tactics can optimize N while minimizing cost.
In this study, we used combinations of composted poultry manure (CPM) and two organic fertilizers (one high N and one with a balance of nutrients) with three GrM crops [rye (Secale cereale), alfalfa (Medicago sativa), and pea (Pisum sativum)] in a loamy sand soil for a 112-day laboratory incubation study. Total plant available N (PAN) was quantified at six times throughout the 16 weeks to determine total N mineralized and rate of N release from each of the management programs.
The CPM and the high N organic fertilizer mineralized completely within the first 6 weeks of the study, while only 65% of the other organic fertilizer mineralized by the end of the study. Total N mineralized from pea grown as a GrM for 48 days was comparable to the amount of N mineralized from rye suggesting that pea as a GrM crop should not receive an N credit in field production on a sandy soil. Significant quantities of PAN were mineralized from alfalfa residue, the equivalent of 80 lb/acre, although this is not sufficient for sweet corn production.
The combination of alfalfa and the high N organic fertilizer provided sufficient N for sweet corn production and the mineralization rate closely matched sweet corn need. The release of N from CPM, even in combination with GrM crops, was asynchronous with sweet corn crop need.
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59. HortScience July 2006 vol. 41 no. 4 981
Can Cover Crop-based Systems Reduce Vegetable Crop Fertilizer Nitrogen Requirements in the Southeastern United States?
Laura Avila1,
Johannes Scholberg2,
Lincoln Zotarelli2 and
Robert McSorely3
HortScience July 2006 vol. 41 no
Poor water- and nutrient-holding capacity of sandy soils, combined with intense leaching rainfall events, may result in excessive N-fertilizers losses from vegetable production systems.
Three cover cropping (CC) systems were used to assess supplemental N-fertilizer requirements for optimal yields of selected vegetable crops. Fertilizer N-rates were 0, 67, 133, 200, and 267; 0, 131, and 196; and 0, 84, 126,168, and 210 kg N/h for sweet corn (Zea mays var. rugosa), broccoli (Brassica oleracea), and watermelon (Citrullus lanatus), respectively. Crop rotations consisted of sunn hemp (Crotalaria juncea) in Fall 2003 followed by hairy vetch (Vicia villosa), and rye (Secale cereale) intercrop or a fallow. During Spring 2004, all plots were planted with sweet corn, followed by either cowpea (Vigna unguiculata) or pearl millet (Pennisetum glaucum), which preceded a winter broccoli crop. Hairy vetch and rye mix benefited from residual N from a previous SH crop. This cropping system provided a 5.4 Mg/ha yield increment for sweet corn receiving 67 kg N/ha compared to the conventional system. For the 133 N-rate, CC-based systems produced similar yields compared to conventional systems amended with 200 kg N/ha. Pearl millet accumulated 8.8 Mg/ha—but only 69 kg N/ha—and potential yields with this system were 16% lower compared to cowpea system.
For a subsequent watermelon crop, trends were reversed, possibly due to a delay in mineralization for pearl millet. Because of its persistent growth after mowing, hairy vetch hampered initial growth and shading also delayed fruit development. Although CC may accumulate up to 131 kg N/ha actual N benefits, N-fertilizer benefits were only 67 kg N/ha, which may be related to a lack of synchronization between N release and actual crop demand.
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60. Broadcast vs. Band Applications of Fertilizer for Vegetable Crops
Richard L. Parish,
Regina P. Bracy and
Hershel F. Morris Jr.,
HortScience July 1997 vol. 32 no
A study was conducted to evaluate the effect of banding or broadcasting fertilizer on yield and quality of turnip (Brassica rapa L. Rapifera group), sweetcorn (Zea mays var. rugosa Bonaf), and cabbage (Brassica oleracea L. Capitata group).
Preplant fertilizer was applied broadcast prior to bedding, broadcast after bedding, or banded after bedding. Sidedress applications were broadcast or banded on the beds.
Strong visual differences were noticed early in the season in the spring turnip crop with the growth in the broadcast-then-bed treatment appearing superior. The yield at first harvest and total yield were lower for turnip growth with the bed-and-broadcast treatments. No differences in yield of cabbage and sweetcorn resulted from the treatments. Few differences in turnip stem to leaf ratio were noted due to fertilizer treatment.
Few differences in yield due to sidedress method were noted with any of the crops. Since broadcasting can be done with a faster, wider applicator, growers could reduce costs by broadcasting fertilizer and obtain yields that are at least equivalent to the yields from banding.
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61. Burns, Ian G., Hammond, John P. and White, Philip J. (2010)
Precision placement of fertiliser for optimising the early nutrition of vegetable crops : a review of the implications for the yield and quality of crops, and their nutrient use efficiency.
Acta Horticulturae, Vol ISSN
The research outlined in this paper highlights the importance of the early nutrition of vegetable crops, and its long-term effects on their subsequent growth and development.
Results are also presented to demonstrate how the nutrient supply during the establishment stages of young seedlings and transplants can be enhanced by targeting fertiliser to a zone close to their developing roots. Three different precision fertiliser placement techniques are compared for this purpose: starter, band or side-injected fertiliser.
The use of each of these methods consistently produced the same (or greater) yields at lower application rates than those from conventional broadcast applications, increasing the apparent recovery of N, P and K, and the overall efficiency of nutrient use, while reducing the levels of residual nutrients in the soil. Starter fertilisers also advanced the maturity of some crops, and enhanced produce quality by increasing the proportions of the larger and/or more desirable marketable grades.
The benefits of the different placement techniques are illustrated with selected examples from research at Warwick HRI using different vegetable crops, including lettuce, onion and carrot.
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62. Laura Avila1, Johannes Scholberg2, Nancy Roe3 and Corey Cherr1
Can Sunn Hemp Decrease Nitrogen Fertilizer Requirements of Vegetable Crops in the Southeastern United States?
Laura Avila1, Johannes Scholberg2, Nancy Roe3 and Corey Cherr1
HortScience July 2006 vol. 41 no
Increased dependency of conventional agriculture on inorganic fertilizers and fossil fuels may hamper long-term sustainability of agricultural production. Sunn hemp (Crotalaria juncea) was tested during summer in a Community Supported Agriculture vegetable crop operation located in Southeast Florida, from 2003 to Farm system components included sunn hemp (SH) vs. a conventional fallow during summer, tomato (Lycopersicon esculentus) and pepper (Capsicum annum) during winter and spring sweet corn (Zea mays). Tomato and pepper were fertilized with 0, 67, 133, 200 kg N/ha (2003) vs. 0,100, 200 kg N/ha (2004/05). Sweet corn received 133 or 200 kg N ha (2003) vs. 100 kg N/ha (2004/05). Average SH biomass was 3.7 Mg/ha. In 2003 tomato yields following SH without supplemental N were similar to fallow, with 200 kg N/ha. By the third year, tomato and pepper yields in SH plots were 25% and 26% higher, respectively. Conventional pepper amended with 200 kg N/ha had only 8% higher yields than treatments amended with 100 kg N ha and CC.
Overall, sweet corn had low yields, but yields increased if the preceding tomato/pepper crop received higher N rates. In 2003, sweet corn fertilized with 200 kg N/ha following a SH-fall vegetable crop produced 17% higher marketable yields compared to the fallow treatment. During 2004 and 2005, sweet corn within the SH-non-fertilized tomato system produced 29% higher yields compared to a similar conventional system. Results show that, in this rotation, both fall vegetable crops and sweet corn yield benefit from residual N fertilizer. Mineralization of SH may thus not only benefit the immediately following crop, but its effects can be seen later during the year.
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63. Owusu A. Bandele, Marion Javius, Byron Belvitt and Oscar Udoh
COVER CROP AND NITROGEN FERTILIZER RATE INFLUENCES ON YIELDS OF SEQUENTIALLY PLANTED VEGETABLES
Owusu A. Bandele, Marion Javius, Byron Belvitt and Oscar Udoh
HortScience June 1992 vol. 27 no
Fall-planted cover crops of hairy vetch (Vicia villosa Roth), Austrian winter pea (Pisum sativum subsp. arvense L. Poir), and crimson clover (Trifolium incarnatum L.) were each followed by spring-planted 'Sundance' summer squash [Cucurbita pepo var. melopepo (L.) Alef.] and 'Dasher' cucumber (Cucumis sativus L.). Squash and cucumber crops were followed by fall 'Florida Broadleaf mustard green [Brassica juncea (L.) Czerniak] and 'Vates' collard (Brassica oleracea L. Acephala group), respectively.
The same vegetable sequences were also planted without benefit of cover crop. Three nitrogen (N) rates were applied to each vegetable crop.
Squash following winter pea and crimson clover produced greater yields than did squash planted without preceding cover crop. Cucumber following crimson clover produced the greatest yields. No cover crop effect was noted with mustard or collard. Elimination of N fertilizer resulted in reduced yields for all crops, but yields of crops with one-half the recommended N applied were generally comparable to those receiving the full recommended rate.
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64. Slow-release Nitrogen Fertilizers in Vegetable Production: A Review
E.A. Guertal1
HortTechnology January-March 2009 vol. 19 no
Slow-release nitrogen (N) fertilizers offer many potential benefits for vegetable production. In sandy soils, their use may lessen N leaching. If the slow-release fertilizer has a release pattern that matches crop needs, N uptake by the growing crop may become more efficient. Additionally, if slow-release fertilizers can be applied as a preplant application, production costs could be lessened, eliminating the need for multiple applications of soluble N fertilizer. Synthetic slow-release fertilizers can be separated into two general groups: those that are slow release as a byproduct of a chemical reaction (such as urea-formaldehyde), and those that are slow release via a sulfur, wax, or resin coating around the fertilizer prill.
In vegetable crop research, much of the available literature has focused on use of sulfur coat urea and urea-formaldehyde, as they have been in the fertilizer market for 40 years. Newer research has evaluated resin-coated products.
In most studies, use of slow-release N fertilizers as a preplant treatment did not decrease crop yield, but yield was rarely increased when compared with standard split applications of soluble N.
Based on available research, the benefits of using slow-release N fertilizers in vegetable crop production will come from reduced environmental risk and savings in production costs.
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65. Broadcast versus Band Fertilizer Applications on Vegetable Crops
R.L. Parish, R.P. Bracy, H.F. Morris Jr.
HortTechnology October-December 1997 vol. 7 no
A study was conducted to evaluate the effect of banding or broadcasting fertilizer on yield and quality of turnip (Brassica rapa L. Rapifera group), sweetcorn (Zea mays var. rugosa Bonaf.), and cabbage (Brassica oleracea L. Capitata group).
Preplant fertilizer was applied broadcast before bedding, broadcast after bedding, or banded after bedding. Sidedress applications were broadcast or banded on the beds. Differences in plant size and vigor were noticed early in the season in the spring turnip crop, with the growth in the broadcast-and-bed treatment appearing superior.
The yield at first harvest and total yield were lower for turnip grown with the bed-and-broadcast treatment. No differences in yield of cabbage or sweetcorn resulted from the treatments. Few differences in turnip stem-to-leaf ratio were noted due to fertilizer treatment. Few differences in yield due to sidedress method were noted with any of the crops.
Analysis of soil samples in a grid pattern across the beds showed that the location of the fertilizer after the broadcast-and-bed treatment was similar to the placement of the banded fertilizer.
Since broadcasting can be done with a faster, wider applicator, growers could reduce costs by broadcasting fertilizer and obtain yields that are at least equivalent to the yields obtained by banding the fertilizer.
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66. …..best management practices ………..
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