KESUBURAN TANAH DAN PEMUPUKAN

KESUBURAN TANAH DAN PEMUPUKAN Unsur Hara dan Sifat Kimia Tanah Sugeng Winarso, Dr.

Departemen of Soil, Faculty of Agriculture, University of Jember http:winarsosugeng.blogspot.com [email protected] 081559544003

Mahasiswa dapat menganalisis dan menjelaskan status kesuburan tanah dan tindakan mempertahankan/meningkatkan kesuburan melalui pemupukan Aplikasi Pemupukan berdasar 5 Tepat Pemupukan Konversi pupuk anorganik ke organik Macam-macam Pupuk dan Soil Amanadement Evaluasi Kesuburan Tanah Unsur Hara Makro (NPK)

Unsur Hara Sekunder dan mikro

Unsur Hara dan Sifat Kimia Tanah

Fisika dan Biologi Tanah

Kondisi lahan Pertanian di Indonesia secara Umum Pemahanan pengertian Kesuburan dan Produktivitas Tanah

Hara Tanaman Unsur hara yang diambil oleh tanaman dari tanah

Hara Makro:

Hara Mikro:

(dibutuhkan dalam jumlah besar)

(dibutuhkan dalam jumlah kecil)

 Nitrogen (N)

 Chlorine (Cl)

 Phosphorus (P)

 Cobalt (Co)

 Potassium (K)

 Copper (Cu)

 Calcium (Ca)

 Iron (Fe)

 Magnesium (Mg)

 Manganese (Mn)

 Sulfur (S)

 Molybdenum (Mo)  Nickel (Ni)  Zinc (Zn)

Dimana tanaman mendapatkan unsur hara yang dibutuhkan?  Sisa tanaman yang melapuk

 Hasil pelapukan minerals tanah  Diberi oleh manusia  Pupuk komersial  Pupuk kandang  kapur

 Lainnya

Siklus hara tanaman

Pelapukan mineral tanah

air asam Zn

Ca K Ni

Mg Cu

The soil solution  Soil water is a complex

solution that contains 

Many types of nutrients  Other trace elements  Complex organic molecules

 Nutrients in the soil solution

can be readily taken up by plant roots

 If nutrients remained in

solution they could all be quickly lost from the soil.

N

Zn

P

Ni

Ca

K

Mg

Cu

Adsorption  Adsorpsi menggambarkan

+

-

kemampuan tanah (bahan) untuk menarik dan mengikat pada permukaannya.  Partikel-partikel padat dalam tanah

mempunyai kemampuan mengadsorp  Air  Hara dan senyawa kimia lainnya

 Pengadsorp penting di dalam tanah

adalah  Liat  Bahan Organik

Daerah Permukaan Liat ¼ cangkir

¼ cangkir liat mempunyai luas permukaan lebih besar dibandingkan dengan lapangan sepak bola

Luas permukaan liat yang besar memungkinkan untuk: • Mengadsorp banyak air • Menyimpan hara-hara • Mempengaruhi partikel tanah lainnya

Macht, F, K Eusterhues, GJ Pronk, and KU Totsche. 2011. Specific surface area of clay minerals: Comparison between atomic force microscopy measurements and bulk-gas (N2) and -liquid (EGME) adsorption methods. Applied Clay Science. Vol 53(1): 20–26 Abstract The specific surface area of natural particles is an important parameter to quantify processes such as mineral dissolution and sorptive interactions in soils and sediments. In this study, the external specific surface area (SSA), specific edge surface area (ESA) and specific basal surface area (BSA) of an illite (Inter-ILI) and a montmorillonite (Ceratosil) were determined by atomic force microscopy (AFM) and compared with the SSA obtained by N2 gas adsorption (BET) and by liquid adsorption using ethylene glycol monomethyl ether (EGME). For the illite we found an SSA of 41 ± 3 m2 g− 1 by BET and of 83 ± 5 m2 g− 1 by analysing 54 particles by AFM. For the montmorillonite BET we estimated a SSA of 61 ± 2 m2 g− 1, whereas the analysis of 62 particles by AFM images gave a much larger mean SSA of 346 ± 37 m2 g− 1. We assume that the sample treatment prior to AFM imaging (involving dispersion by NaOH in a dilute dispersion and sonication for 2 min) resulted in delamination of the clay mineral particles. The ESA was 5.6 ± 0.4 m2 g− 1for the illite, and 15 ± 2 m2 g− 1 for the montmorillonite. This leads to an ESA/BSA ratio of 0.07 for the illite and 0.05 for the montmorillonite for the delaminated particles. For the untreated, nondelaminated particles we calculated an ESA/BSA ratio of 0.16 for the illite and of 0.27 for the montmorillonite. The specific surface area as estimated by EGME was 112 m2 g− 1 for the illite and 475 m2 g− 1 for the montmorillonite, i.e. about 30–40% larger than the respective AFM values. However, this difference in specific surface area was not in agreement with the expected interlayer surface area of both minerals.

Sifat-sifat Liat Tanah Partikel liat tersusun dalam lapisan-lapisan seperti kertas. Setiap lembar liat terpisah dengan yang lainnya. Setiap lembar mempunyai muatan negatif pada permukaannya. Muatan negatif tersebut harus disetimbangkan oleh muatan positif atau disebut kation.

Clay Mineral Structures  Clays are aluminosilicate minerals. (They contain layers of silica bonded to layers of alumina).

 Clays are classified by the number and arrangement of these sheets.  Water can be hydrogen bonded on the surface of or between sheets.  Metal cations (Na, K, Ca, Fe, Mg) in the water will swap places with Al, giving individual clays unique colors and hydrologic properties.

Posisi Unsur hara dan Reaksi Pengapuran

Retensi Kation pada Permukaan Liat Calcium, +2 Magnesium, +2 Potassium, +1 Ammonium, +1 Sodium, +1 Copper, +2 Aluminum, +3 Hydrogen, +1

Retensi Kation pada Bahan Organik Hidrogen Hara

pH meningkat, meningkatkan kemampuan bahan organik untuk mempertukarkan kation

pH rendah, 4 - 5 (tanah masam)

pH netral, ~7 (tanah ideal)

Cation Exchange Capacity  Cation exchange capacity

(CEC) is the total amount of cations that a soil can retain  The higher the soil CEC the

greater ability it has to store plant nutrients  Soil CEC increases as  The amount of clay increases  The amount of organic matter

increases  The soil pH increases

Estimated cation exchange capacity (CEC) of soils typical for New York State agricultural land (modified from: Cornell Field Crops and Soils Handbook, 1987). SMG* General Description CEC (cmolc/kg soil) 1 Fine-textured soils developed from clayey lake sediments and medium- to fine-textured soils developed from lake sediments. 25 2 Medium- to fine-textured soils developed from calcareous glacial till, medium-textured to moderately fine-textured soils developed from slightly calcareous glacial till mixed with shale, and medium-textured soils developed in recent alluvium. 20 3 Moderately coarse textured soil developed from glacial outwash and recent alluvium and mediumtextured acid soil developed on glacial till. 18 3 Coarse- to medium-textured soils formed from glacial till or glacial outwash. 16 4 Coarse- to very coarse-textured soils formed from gravelly or sandy glacial outwash or glacial lake beach ridges or deltas. 12 * SMG = soil management group.

Negatively Charged Nutrients (Anions)

 Some very important plant nutrients are anions.

Nitrate

Phosphate

Sulfate

Chloride

 Soils are able to retain some of these nutrient

anions.  Retention of nutrient anions varies from one anion to

another

Phosphate retention in soil 1. Formation of a new solid material

+ Phosphate

Aluminum phosphate solid Aluminum 2. Anion exchange

Phosphate

Geometry of aluminium 4 coordinate : tetrahedral Element

%

Al

22.12

O

52.48

P

25.40

Phosphate retention in soil 3. Adsorption on oxide surfaces

Phosphate anions Each held by two chemical bonds to the iron oxide surface Iron oxide surface

Nitrate (NO3-) retention in soils Unlike phosphate, nitrate is very weakly held by soils • Nitrate does not react to form new solids • Nitrate is not held by oxide surfaces

If nitrate is not taken up by plants it is very likely to be lost from the soil

NO3-

Moving nutrients from soil to plants Nutrients in soil solution

Plant Root

Nutrients on soil clay and organic matter

Excessive Nutrient Loading Nutrients in soil solution

Plant Root

Nutrients on soil clay and organic matter

Nutrient loss in drainage water

The black box is open  Soil consists of mineral and organic matter, air and

water  Soils are able to adsorb nutrients and other chemicals  The most important adsorbers are clay and organic matter • Adsorbed nutrients are available to plants • Adsorbed nutrients are not prone to loss in drainage water • Soil adsorption capacity can be exceeded leading to greater nutrient loss

CP atau LO Sikap dan Tata Nilai Penguasaan Pengetahuan Kemampuan Bidang Kerja Kemampuan Manajerial

Menteri Koperasi dan Usaha Kecil Menengah (UKM), A.A.G.N Puspayoga mengatakan Indonesia masih tertinggal dalam jumlah wirausahawan dibandingkan sejumlah negara di ASEAN. Jumlah wirausahawan kita hanya 1,65% dari 250 juta penduduk. Amerika Serikat mencapai 12% China dan Jepang 10%, Singapura dan India 7%, Malaysia 5%, Thailand 4% dari total populasi Target menjadi 2 persen untuk menaikkan kelas pengusaha Indonesia

Dengan jumlah populasi Indonesia saat ini, secara proporsional dibutuhkan 4,8 juta wirausahawan, sebagai prasyarat pembangunan ekonomi suatu negara Realitasnya, saat ini proporsi wirausaha Indonesia baru sekitar 0,24 persen dari populasi penduduk atau sekitar 500.000 an orang