1. DINAMIKA KALIUM DALAM TANAH
SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎

2. Forms of Potassium in soil
Dinamika K dalam Tanah
Introduction
The Potassium Cycle
Forms of Potassium in soil
Ketersediaan K dalam tanah
Manajemen K tanah
SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎

3. SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎
Pendahuluan
K is the third most likely element after nitrogen and phosphorus to limit plant productivity.
Biasanya diaplikasikan sebagai pupuk
K ada dalam larutan tanah sebagai kation K+
K tidak membentuk gas yang hilang ke udara
SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎

4. SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎
Pendahuluan
Its behavior in soil is influenced more by cation exchange reactions than by microbiological processes
K tidak menyebabkan pencemaran lingkungan eksternal
K tidak toksik dan tidak menyebabkan problematik eutrofikasi
SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎

5. K dalam nutrisi tanaman dan hewan
Potassium activates many enzymes in plants and animals that are responsible for energy metabolism, photosynthesis and other processes
As a component of the cytoplasm of plant cells, it helps to lower cellular osmotic water potential thereby increasing the ability of root cells to take up water.
SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎

6. K dalam nutrisi tanaman dan hewan
K sangat penting untuk fiksasi nitrogen pada legume
Kecukupan K telah terbukti membantu tanaman beradaptasi terhadap cekaman lingkungan
In animals including humans, K is important in regulating the nervous system and maintenance of good blood vessels.
SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎

7. SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎
Gejala Defisiensi K
Mengurangi kemampuan tanaman untuk beradaptasi terhadap cekamam lingkungan mis. Kekeringan, Genangan banjir, dll.
Pucuk dan tepian daun menguning (chlorosis) dan kemudian mati (nekrosis).
In some crops, K deficiency produces white necrotic spots that looks like insect damage.
SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎

8. SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎
Siklus K
SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎

9. SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎
Siklus K
Sumber Original K adalah mineral primer
Mineral Mica (biotite dan muscuvite)
Potassium feldspar (orthoclase dan microcline)
Potassium is released from the minerals during the weathering process
When available for plant uptake, it is taken up by plants in large quantities
SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎

10. SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎
Siklus K
Dalam ekosistem alamiah, K is returned to the soil by rainwater leaching of foliage and by plant residue or as waste from animals that feed on plant
Potassium is lost by soil erosion and runoff, and leaching to the groundwater
Most potassium in agricultural ecosystems are lost through removal of crops and crop residues from soil
SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎

11. Bentuk-bentuk K dalam tanah
Empat bentuk K dalam tanah adalah:
K dalam struktur mineral primer
K dalam posisi tidak dapat ditukar dalam mineral sekunder
K in exchangeable form on soil colloid surfaces
K ions larut dalam air
Total K in soil and its distribution as shown in the K-cycle is a function of the clay minerals present in soil
SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎

12. Ketersediaan bentuk-bentuk K
K dalam struktur mineral primer
Unavailable (90-98% of all soil K)
K dalam posisi tidak dapat ditukar pada mineral sekunder
Slowly available
fixed K is not easily exchangeable
In equilibrium with more available forms
K dalam bentuk dapat ditukar pada permukaan koloid tanah
Readily available (1-2% of all soil K)
-90% of readily available
Ion K+ larut dalam air
Readily available
Subject to leaching
Equilibrium with exchangeable form
SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎

13. Fiksasi K oleh Koloid Tanah
Nonexchangeable-K  Exchangeable-K  Soil Solution-K
SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎

14. Faktor Ketersediaan K dalam tanah
Tipe Koloid Tanah
Ability of various colloids to fix K varies (2:1)
Pembasahan & Pengeringan Tanah
Physically affects the structure of colloids
Pembekuan & Pencairan Tanah
Kemasaman tanah (pH)
High pH increases the fixation of K because of less H+ and Al3+ at exchange sites.
SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎

15. Problem K dalam Kesuburan Tanah
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16. SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎
Pengelolaan Kalium
The main problem with managing soil K is that of converting the unavailable forms of the element to available forms
Available K is usually supplemented by fertilization
Another problem is removing a lot of crops from the soil without returning the crop residues
Attempts should be made to return as much residue as possible for the natural plant-soil cycling of K to continue
SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎

17. SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎
Pengelolaan Kalium
Growing high K content plants places demand on the soil supply of potassium
To have high yields of such crops, e.g., alfalfa, it needs to planned in advance to supply soil with enough K to last the cropping season –fertilization
Pemupukan dengan dosis ringan dan sering ternyata lebih baik daripada dosis tinggi sekali aplikasi, hal ini dapat mengurangi konsumsi mewah K
Pengapuran tanah ternyata meningkatkan retensi K dalam atanah.
SUMBER: myspace.aamu.edu/users/monday.mbila/soils/SPS251Lecture15.ppt‎

18. SUMBER: http://www.ipipotash.org/en/presentn/aspcwdb.php ‎
Kalium Tanah
Efek status K-tanah thd hasil tanaman dan efisiensi pupuk N (JOHNSTON et al., 2001)
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19. SUMBER: http://www.ipipotash.org/en/presentn/aspcwdb.php ‎
Kalium Tanah
Respon tanaman thd K dalam percobaan jangka panjang ( ) (MERBACH et al., 1999)
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20. Kalium Tanah
Siklus kalium dalam sistem tanah-tanaman-ternak (SYERS, 1998)
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21. Bentuk-bentuk K-tanah dan ketersediaannya bagi tanaman.
Kalium Tanah
Bentuk-bentuk K-tanah dan ketersediaannya bagi tanaman.
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22. Siklus Kalium dalam Tanah
Status K-tanah mempengaruhi penyerapan K oleh akar tanaman.
Jumlah K dalam tanah tergantung pada tipe-tanah, produksi tanaman, retensi atau panen biomasa residu tanaman, pemupukan K dan irigasi.
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23. SUMBER: Ben Zioni et al., 1971; Physiolgia Plantarum 24:288-290.
Kalium Tanah
Penyerapan NO3- oleh akar tanaman dikendalikan oleh hasil reduksi NO3- dalam tanaman dan siklus K+ dalam tanaman.
SUMBER: Ben Zioni et al., 1971; Physiolgia Plantarum 24:

24. Kalium Tanah
Model mineral liat tipe 1:2 (illite) yang menunjukkan posisi penjerapan K+
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25. Model pelepasan K dalam proses pelapukan mineral primer tanah
Kalium Tanah
Model pelepasan K dalam proses pelapukan mineral primer tanah
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26. Kalium Tanah Kesetimbangan bentuk-bentuk K dalam tanah.
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27. SUMBER: http://www.cropnutrition.com/efu-potassium#in-soil ‎
Siklus Kalium Tanah
Sekitar % total K dalam tanah dalam bentuk ineral primer tidak-larut, mineral ini thaan terhadap pelpaukan kimiawi. Pelepasan K dari mineral primer ini sangat lambat, dan jumlahnya sangat kecil dibandingkan dnegan kebutuhan tanaman.
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28. Kalium Tanah K dalam larutan tanah mudah diserap oleh akar tanaman.
K-larutan tanah ini jumlahnya sangat kecil.
Uji K untuk larutan tanah tidak mencerminkan total K yang tersedia bagi tanaman.
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29. Faktor penyerapan K oleh tanaman:
Kalium Tanah
Faktor penyerapan K oleh tanaman: 
Kandungan Oksigen Tanah – oxygen is necessary for proper root function, including uptake of potassium
Air tanah - the more moisture found in the soil, the easier it is for plants to absorb potassium.
Olah-tanah – research has shown that regularly tilled soil allows for better potassium uptake.
Suhu Tanah – degrees Fahrenheit is the ideal soil temperature range for root activity and most of the physiological processes in plants. The lower the temperature, the slower absorption becomes.
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30. SUMBER: http://www2.ca.uky.edu/agc/pubs/agr/agr11/agr11.htm ‎
Siklus Kalium Tanah
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31. Fiksasi Kalium oleh mineral liat Tanah
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