Soil as a habitat for microorganisms to function as a natural medium for growth and doing all the activities physiology. Soil provides nutrients, water and carbon source necessary for the growth and activity of microorganisms. In this respect, the soil environment as abiotic factors (which include physical and chemical properties of the soil) and biotic (presence of other microbes and higher plants) play a role in determining the rate of growth and activity of soil microorganisms.
Soil structure, soil aeration, soil moisture and soil temperature are physical properties that play a role in determining the survival of physiological processes of micro-organisms. While between soil chemical properties that affect soil microorganisms are soil pH, redox potential and the presence or absence of a toxic substrate. As a microbial habitat, land inhabited by more than one species of microorganisms with various species.
Fellow microorganisms mempengaru mutual-hi, interdependent, and even less so with one another do the competition in order to survive. In the soil, microorganisms not only interact with other micro-organisms, but also with higher organisms like plants that grow in the vicinity. In this case the roots of the plant would release a number of organic compounds that are useful as a source of carbon and energy for the life of microorganisms, although there are also compounds that are poison for a certain type of microorganisms.
Their poison compound will cause the growth or activity of microorganisms in improving the availability of nutrients for absorption by the plant at the same plant will be stunted or even halted. Interaction Between microorganism populations of microorganisms that inhabit a land usually more than one type of microorganisms. Among microorganisms will interact, either the interaction of neutral, positive and can also be negative.
Neutral forms of interaction always occur on a regular basis, and are highly experienced. The presence of a population in a neutral interaction does not have direct influence on the life and development of the population to another. Mutual interaction a positive influence on each population known as a form of symbiosis, both in the form of mutualism and protokooperatif. Forms of interaction opposite, known as the life patterns of antagonism which is a form of interaction the detriment of the other, whether in the form of parasitism or amensalisme.
Forms of association between microorganisms in the soil, can be changed from one form to another, these changes can occur due to the passage of time or due to changes in the environment. Examples of growth rate per individual predator (predator) which is highest when the density is high, and when the prey population growth rate became negative. However, when the prey population drops below the threshold, the predator population also fell, and at that moment habitat complexity gives them a chance to live together.
Effect of associative or antagonistic among the various microorganisms in the life and development in the soil takes place as a result of (1) changes in the availability of nutrients, (2) changes in environmental factors, (3) the dependence of life certain microorganisms over another life is shared between bacteria perombak cellulose with or heterotrophic bacteria autotrof and the other is a form of association komensalisme which is based on the availability of nutrients. Perombak bacterial cellulose will be to produce products of inorganic compounds, organic acids and essential product intermediates for various activities of microorganisms non perombak cellulose.
Coexistence between anaerobic bacteria with aerobic bacteria is a good example to see patterns komensalisme which was based on environmental changes. Aerobic bacteria will consume free oxygen in the soil, so as to create favorable conditions for the growth of anaerobic microorganisms. Coexistence between bacteria Nitrosomonas and Nitrobacter is an example of the dependence of certain microorganisms living on the other.
Nitrosomonas bacteria oxidize ammonia to nitrite form. This latter compound is the only compound N required for activities Nitrobacter bacteria to form nitrate. These bacteria are not able to use other energy sources. Competition in obtaining nutrients, as happens between bacteria and fungi is a common example of an antagonistic effect on the pattern of competition. It thus also occurred in the same microbial groups, eg between the inoculum is inserted into the ground (Azospirillum) with Azospirillum strains contained in the soil.