DINAMIKA KALIUM DALAM TANAH. SUMBER: myspace.aamu.edu/users/monday.mbila/soils/sps251lecture15.ppt

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DINAMIKA KALIUM

DALAM TANAH

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Dinamika K dalam Tanah



Introduction



_{The Potassium Cycle}



_{Forms of Potassium in soil}



Ketersediaan K dalam tanah



Manajemen K tanah

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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

(4)

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

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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.

(6)

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.

K dalam nutrisi tanaman dan hewan

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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.

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Siklus K

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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

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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

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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

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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

Ketersediaan bentuk-bentuk K

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Fiksasi K oleh Koloid Tanah

Nonexchangeable-K  Exchangeable-K  Soil Solution-K

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Faktor Ketersediaan K dalam tanah

1. Tipe Koloid Tanah

Ability of various colloids to fix K varies (2:1)

2. Pembasahan & Pengeringan Tanah

Physically affects the structure of colloids

3. Pembekuan & Pencairan Tanah

Physically affects the structure of colloids

4. Kemasaman tanah (pH)

High pH increases the fixation of K because of less H

+

_and

Al

3+

_{at exchange sites.}

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Problem K dalam Kesuburan Tanah

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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

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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.

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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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Kalium Tanah

Respon tanaman thd K dalam percobaan jangka panjang (1949-91)

(MERBACH et al., 1999)

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Kalium Tanah

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SUMBER: http://www.depi.vic.gov.au/agriculture-and-food/dairy/pastures-management/fertilising-dairy-pastures/what-nutrients-do-plants-require

Kalium Tanah

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SUMBER: http://www.ipipotash.org/en/eifc/2011/29/3

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

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SUMBER: Ben Zioni et al., 1971; Physiolgia Plantarum 24:288-290.

Kalium Tanah

Penyerapan

NO

₃-

_{oleh akar}

tanaman

dikendalikan

oleh hasil

reduksi NO

₃

-dalam tanaman

dan siklus K

+

dalam tanaman.

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SUMBER: http://www.intechopen.com/books/soil-processes-and-current-trends-in-quality-assessment/potassium-in-soils-of-glacial-origin

Kalium Tanah

Model mineral liat tipe 1:2 (illite) yang menunjukkan posisi

penjerapan K

+

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Kalium Tanah

SUMBER: http://www.intechopen.com/books/soil-processes-and-current-trends-in-quality-assessment/potassium-in-soils-of-glacial-origin

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SUMBER: http://people.umass.edu/psoil120/guide/chapter7.htm

Kalium Tanah

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SUMBER: http://www.cropnutrition.com/efu-potassium#in-soil

Siklus Kalium Tanah

Sekitar 90 -98 % 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

(28)

SUMBER: http://www.smart-fertilizer.com/articles/potassium-in-soil

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

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Kalium Tanah

Faktor penyerapan K oleh tanaman:

1. Kandungan Oksigen Tanah – oxygen is necessary for

proper root function, including uptake of potassium

2. Air tanah - the more moisture found in the soil, the

easier it is for plants to absorb potassium.

3. Olah-tanah – research has shown that regularly tilled

soil allows for better potassium uptake.

4. Suhu Tanah – 60-80 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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SUMBER: http://www2.ca.uky.edu/agc/pubs/agr/agr11/agr11.htm

Siklus Kalium

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SUMBER: http://www2.ca.uky.edu/agc/pubs/agr/agr11/agr11.htm