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Key process: Decomposition, humification: Parent material: Plant and animal detritus, microbial biomass: Climate: Variable, higher in cooler and wetter regions ...
Soil microbial communities are characterized in many different ways. The activity of microbes can be measured by their respiration and carbon dioxide release. The cellular components of microbes can be extracted from soil and genetically profiled, or microbial biomass can be calculated by weighing the soil before and after fumigation.
They are the most abundant microorganisms in the soil, and serve many important purposes, including nitrogen fixation. [9] Some bacteria can colonize minerals in the soil and help influence weathering and the breaking down of these minerals. The overall composition of the soil can determine the amount of bacteria growing in the soil.
Soil biology is the study of microbial and faunal activity and ecology in soil. Soil life , soil biota , soil fauna , or edaphon is a collective term that encompasses all organisms that spend a significant portion of their life cycle within a soil profile, or at the soil- litter interface.
Nitrogen is an essential element needed for the creation of biomass and is usually seen as a limiting nutrient in agricultural systems. Though abundant in the atmosphere, the atmospheric form of nitrogen cannot be utilized by plants and must be transformed into a form that can be taken up directly by the plants; this problem is solved by biological nitrogen fixers.
This microbial biomass serves as a reservoir for stored carbon in the soil, effectively sequestering carbon from the atmosphere. Additionally, soil microbes contribute to the formation of stable soil organic matter through the synthesis of extracellular polymers , enzymes , and other biochemical compounds. [ 34 ]
The process that converts soil organic matter into humus feeds the population of microorganisms and other creatures in the soil, and thus maintains high and healthy levels of soil life. [ 53 ] [ 54 ] The rate at which soil organic matter is converted into humus promotes (when fast, e.g. mull ) or limits (when slow, e.g. mor ) the coexistence of ...
In general plant residues entering the soil have too little nitrogen for the soil microbial population to convert all of the carbon into their cells. If the C:N ratio of the decomposing plant material is above about 30:1 the soil microbial population may take nitrogen in mineral form (e.g. nitrate). This mineral nitrogen is said to be immobilized.