1 / 42

MIKROORGANISME & BAHAN ORGANIK TANAH

MIKROORGANISME & BAHAN ORGANIK TANAH. AGROTEKNOLOGI. In 1 teaspoon of soil there are…. Travis & Gugino - PSU. Soil Organisms. Significance/Fungsinya 1. Decomposition of plant and animal residues

lidia
Download Presentation

MIKROORGANISME & BAHAN ORGANIK TANAH

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. MIKROORGANISME& BAHAN ORGANIK TANAH AGROTEKNOLOGI

  2. In 1 teaspoon of soil there are… Travis & Gugino - PSU

  3. Soil Organisms Significance/Fungsinya 1. Decomposition of plant and animal residues 2. Release of nutrients and inorganic elements which feed plants and cause mineral weathering 3. Synthesis of new organic compounds 4. Humus formation to increase cation exchange and structure 5. Nitrogen fixation

  4. Soil Organisms Cont. Kind 1. Plant 2. Animal Plants ( bacteria, actinomycetes, fungi, algae) 1. Bacteria 1. Very small single celled organisms 2. Multiply by elongation and dividing into 2 parts 3. Millions or even billions per gram of soil

  5. I. Classification of Bacteria (Heterotropic) A. Heterotropic obtain their carbon and energy from various organic compounds 1. Nitrogen fixing derive their nitrogen in gaseous form from the atmosphere or they can obtain their nitrogen from Ammonia or Nitrates a. Non Symbiotic - those that are free living 1. Anaerobic organisms - those not needing free oxygen for respiration Don’t need Host Plant

  6. Clostridium • More common in forest soils • Optimum Reaction pH 6.9 - 7.3 • no fixation below pH 5.0 • 2. Aerobic- need free oxygen • Azotobacter • More common in agriculture soils • Very sensitive to acidity • pH below 5.5 to 6.0 no fixation

  7. b. Symbiotic - live on host plant to mutual advantage • Rhizobium • - Find on nudules • - Nitrogen from the air • c. Aerobic Bacteria- requiring combined Nitrogen • Bacillus mycoides • - Cause denitrification • d. Anaerobic Bacteria - which require combined Nitrogen • - Nitrates ---------- Nitrites, ammonia • - Sulfates ---------- Sulfites, sulfides

  8. Classification of Bacteria (Autotrophic) B. Autotrophic- derive their carbon primarily from CO2 of the atmosphere and their energy from the oxidation of inorganic compound or simple compounds of carbon

  9. Cont. 1. Bacteria using nitrogen compounds as an energy source a. Nitrosomes - oxidize ammonium Nitrite - NH4+ NO2-

  10. Cont. b. Nitrobacter - Oxidize Nitrite to Nitrate - NO2- NO3- - little or no activity below a pH of 6.0 - little or no activity below a temp of 65oF 2. Bacteria using sulfur or sulfur compounds as energy sources. a. Thiobacillus S + O2 + H2O H2SO4

  11. Ed Basgall SOIL MICROORGANISM Bacteria UBC EM facility Pseudomonas Arthrobacter CIMC Bacillus Travis & Gugino - PSU

  12. II. Actinomycetes Unicellular micro-organisms Transitional between the bacteria and fungi Effect of soil pH a. Sensitive to acid soil- no activity below pH 5.0, optimum activity between 6.0 - 7.5 Heterotropic Feeders- breaks down organic matter and humus liberating nutrients, especially nitrogen form NH3

  13. SSSA Univ of Iowa Actinomycetes Paul R. August Streptomyces Travis & Gugino - PSU

  14. Nitrogen Cycle

  15. III. Fungi Heterotropic organisms Fungi will tolerate a wide pH range • abundant in acid soils where bacteria and actinomycetes offer only limited competition Activities of Fungi • Decompose organic residues

  16. Fungi Cont. Micorrhiza- fungus roots more common in forest soils fungal roots form a mat around the absorbing root while others penetrate the root cells • Symbiotic relationship- help with nutrient absorption by increasing absorptive surface • Pine seedlings will not grow well without them

  17. Microorganisms Fungi Aspergillus Trichoderma K.J. Kwon-Chung PSU Em facility D.C. Straney Fusarium Travis & Gugino - PSU

  18. Mycorrhizae

  19. IV. Algae minute plants which are photosynthetic found in surface soils but in low amounts Blue green types are important in wet soil • fix nitrogen in rice paddies • give off oxygen to the water

  20. Soil Macro Animals Include- rodents, insects, millipedes, centipedes, earthworms Earthworm- most important macro animals • may pass as much as 15 tons of dry earth per acre through their bodies Micro-organisms and the nitrogen cycle Organic matter of mineral soils Source- remains of plants and animals

  21. Nematodes

  22. Many beneficial effects from activities of microorganisms • Microorganisms produce: • Plant growth hormones • Stimulate plant growth hormones • Compete with disease organisms

  23. SOIL ORGANIC MATTER (BAHAN ORGANIK TANAH)

  24. About ½ of the soil volume is solid particles About ½ of the soil volume is pore space Soil ComponentsThe 4 parts of soil

  25. Soil Organic Matter • SOM consists of a broad spectrum of chemical classes, including amino acids, lignin, polysaccharides, proteins, cutins, chitins, melanins, suberins, and paraffinic macromolecules, as well as organic chemicals produced by humans.

  26. SOIL ORGANIC MATTER • Soil Organic matter encompasses all organic components of a soil: • Fresh residues • Decomposing organic matter • Stable organic matter • Living organisms

  27. Composition • of green tissue 75% is water • of dry matter in mature plants • Sugars and starches 1-5% • Carbohydrates Hemicellulose 10-28% • Cellulose 20-50% • Fats, waxes, tannins, etc 1-8% • Lignin's 10-30% • Proteins Simples water soluble 1-15% • and crude protein

  28. Changes of Organic Compounds in the Soil I. Compounds Characteristic of Fresh Plant Tissue Decompose with difficultyDecompose easily Lignin Cellulose Fats Starches Oils Sugars Resin Proteins

  29. II. Complex Intermediate Products of Decay Resistant compoundsDecomposition compounds Resigns Amino acids Waxes Amides Oils and Fats Alcohols Lignin Aldehydes III. Products of Soil-Decomposition Processes Resistant complexSimple end products Humus- a colloidal complex carbon dioxide and water nitrates, sulfates phosphates, calcium compounds

  30. Rate of Decomposition - Burning process - oxidation 1. Sugars - Starches - simple proteins Rapid 2. Crude proteins 3. Hemicellulose 4. Cellulose 5. Lignins, fats, waxes Very Slow

  31. The Carbon Cycle - cycle of life energy cycle CO2 Animal To Atm. Green Manure & Crop Residue Farm Manure Soil Reactions CO3 , HCO3 Microbial Activity Carbon Dioxide Drainage losses CO2 & Carbonates & Bicarbonates of Ca, Mg, K, Etc.

  32. Humus Humus is a mixture of complex compounds and is not a single material. These compounds are either (a) resistant materials (b) compounds synthesized within microbial tissue. Definition- Humus is a complex and rather resistant mixture of brown or dark brown amorphous and colloidal substances that have been modified from the original tissue or have been synthesized by various soil organisms

  33. Humus Properties 1. highly colloidal 2. amorphous (not crystalline) 3. cation exchange Cap. 150-300 me/100 gms. Clay 8-100 me/100 gms. 4. absorption of water from sat. atmosphere 80-90% clay 15-20%

  34. Carbon : Nitrogen Ratio Carbon : Nitrogen ratio fairly constant in soils • in cultivated soils 10 or 12:1 is a common ratio • in plant material Legumes 20:1 Straw 90:1 Sawdust 150:1 Thus it can be seen that organic matter contains large amounts of carbon and comparatively small amounts of nitrogen.

  35. Influence of Soil Organic Matter on Soil Properties 1. Soil Color - brown to black 2. Influence on physical properties - granulation encouraged - plasticity cohesion reduced - H2O holding capacity increased

  36. 3. High cation adsorption - 2 x 20 x clay - 30 - 90% adsorbing power of mineral soils 4. Supply and availability of nutrients - N, P and S held in organic forms - Manure (10 - 5 - 10)/ ton (5 - 1 - 5) N P K Available

  37. QUANTITY IN SOILS • SOM in mineral soil up to 18% by weight • Typically 0.5 to 5%. • SOM > 18% in organic soils • SOM about 50% C • SOM = (OC)(factor) where the factor = 1.8 to 2.0 • For most estimations 2 is a good round number • Older books use a factor = 1.724

  38. How is SOM Measured? SOM is usually measured in the laboratory as organic carbon, Soil organic matter is estimated to contain 58% organic carbon (varies from 40 to 58%) with the rest of the SOM comprising of other elements (eg, 5% N, 0.5% P and 0.5% S). A conversion to SOM from a given organic carbon analysis requires that the organic carbon content be multiplied by a factor of 1.72 (1.00/0.58). Thus, 2% SOM is about 1.2% organic carbon. Testing for Soil Organic Carbon

  39. Walkley Black • Oxidize SOM to CO2 using acid dichromate • Assume C is in the zero oxidation state as in carbohydrates (CH2O). 3CH2O + 16H+ + 2Cr2(VI)O72- --> 4Cr3+ + 3CO2 + 11H2O Titrate excess Cr2(VI)O72- with Fe2+ • Not used much any more

  40. Components of SOM

  41. KESIMPULAN • Roles of Soil organisms : Decomposition of plant and animal residues, Release of nutrients and inorganic elements, synthesis of new organic compounds, Humus formation, Nitrogen fixation • Soil organic matter : all living organisms (microorganisms, earthworms, etc), fresh residues (old plant roots, crop residues, recently added manures), decomposing organic matter and stable organic matter (humus). • Influence of Soil Organic Matter on Soil Properties : Soil Color - brown to black, Influence on physical properties (granulation , plasticity , H2O holding capacity ), High cation adsorption, Supply and availability of nutrients. • SOM is usually measured in the laboratory as organic carbon, A conversion to SOM from a given organic carbon analysis requires that the organic carbon content be multiplied by a factor of 1.72 (1.00/0.58).

More Related