The role of microorganisms in soil fertility indicated by its activities in improving, (1) the structure of the soil and (2) the availability of plant nutrients. In connection with the formation of crumb structure, microorganisms play a role as a builder of soil aggregates steady. In the process of the formation of the land required agragasi their inorganic adhesive materials (such as Fe, clay, oxidation of iron, aluminum and lime) and organic material (organic compounds formed by microorganisms or decomposition of organic material).
Consider the following Figure 1:36. This image shows the different types of microorganisms in the soil that is influential in improving soil fertility. What and how the role of these microorganisms in improving soil fertility?
Figure 1:36 Soil Microorganisms
Such compounds bind the grains of soil, both on the ground into the shape koogulasi micro aggregate and aggregate cementation micro into the macro aggregates. In relation to the increase in the availability of nutrients, microorganisms function as accelerate the decomposition of organic matter and as a driver solubility of inorganic compounds which are not available into the form provided. It can last for their secondary metabolic produced by microorganisms in the form of enzymes, soil and some organic compounds that are useful as solvents.
The formation of soil aggregates by microorganisms, can occur (1) through a mechanical binding by the bacterial cell, aktinomesetes and fungal hyphae, and (2) through binding dipelantarai by organic compounds that result or the result of decomposition of organic matter. The binding is mechanically mainly done by fungi and actinomycetes, because these micro-organisms have a filament that serves as a binder of soil particles to form the structure of the crumb.
This does not mean that the two mikoflora does not produce chemical perekt material. The mechanism of formation of aggregates by fungi and actinomycetes is 50% takes place mechanically, and 50% longer takes place using an adhesive material of compound oeganik produces. Unlike the case with fungi and actinomycetes, bacteria more of binding soil particles using organic compounds that result from the conduct binding mechanically, with a ratio of 80% and 20%.
Effectiveness of microorganisms in the soil aggregate formation relies heavily on (1) the nature of the organic material available, (2) types of microorganisms and environmental conditions that affect the growth and activity. Generally, organic material is decomposed, less effective for soil aggregation. Therefore if inserting the organic material into the soil for the purpose of pembenah aggregate, it requires organic material bernisbah C / N ratio with a high lignin / cellulose is also high.
Examples of organic materials The following sequence of effectiveness from high to low, respectively straw, manure and legume plants. Please also note that when organic material decomposes easily incorporated into the soil, aggregation takes place immediately after the addition, but quickly, after reaching a maximum, decreased aggregation. Based on the above, there is a very close relationship between the land as a habitat for soil organisms to agriculture, particularly soil fertility.