What is the role of microorganisms in increasing soil fertility and role of microorganisms in soil decomposition and nutrient cycling?
Soil Organic Matter Decomposition
- Organic matter decomposition provides energy for growth and supplies carbon for the formation of new cells.
- Soil organic matter (SOM) is composed of "living" (microorganisms), "dead" (fresh residues), and "very dead" (humus) fractions.
Soil Organic Matter Nutrients
- The nutrients in the soil have a current value of $680 for each 1 percent SOM or $68 per ton of SOM based on economic values for commercial fertilizer.
- SOM is composed of mostly carbon but associated with the carbon is high amounts of nitrogen and sulfur from proteins, phosphorus, and potassium.
Microbial Soil Organic Matter Decomposition
- Microbes need regular supplies of active SOM in the soil to survive in the soil.
- Long-term no-tilled soils have significantly greater levels of microbes, more active carbon, more SOM, and more stored carbon than conventional tilled soils.
Carbon to Nitrogen Ratio
- The break down of organic residues by microbes is dependent upon the carbon to nitrogen (C:N) ratio.
- A low nitrogen content or a wide C:N ratio is associated with slow SOM decay.
Sourced from https://ohioline.osu.edu/factsheet/SAG-16
Soil microorganisms are responsible for most of the nutrient release from organic matter. When microorganisms decompose organic matter, they use the carbon and nutrients in the organic matter for their own growth. They release excess nutrients into the soil where they can be taken up by plants. This is because microorganisms decompose dead organic waste of plants and animals converting them into simple substances. These substances are again used by other plants and animals. Thus, microorganisms can be used to degrade harmful and odourific substances and clean up the environment. They increase soil fertility by incorporating air, minerals and nitrogenous compounds. They contribute in increasing plant growth by providing essential elements, minerals that plants cannot utilize by their Owen. Microorganisms decompose organic matter to simpler form that can be easily uptake by plants. Bacteria help fix the atmospheric nitrogen with the help of nitrogenase enzyme and increase the nitrogen content in the soil. It is referred to as Nitrogen-fixing Bacteria. Soil microorganisms, by actively participating in the decomposition and transformation of organic matter through diverse metabolic pathways, play a pivotal role in carbon cycling within soil systems and contribute to the stabilization of organic carbon, thereby influencing soil carbon storage and turnover. Bacteria break down (or decompose) dead organisms, animal waste, and plant litter to obtain nutrients. But microbes don't just eat nature's waste, they recycle it. The process of decomposition releases chemicals (such as carbon, nitrogen, and phosphorus) that can be used to build new plants and animals. Microorganisms play a crucial role in nutrient cycling in soil. The composition and activity of microbiota impact the soil quality status, health, and nutrient enrichment. Microbes are essential for nutrient mobility and absorption. Through their varied functions, they stimulate plant growth and reduce diseases. Decomposition by soil organisms is at the center of the transformation and cycling of nutrients through the environment. Decomposition liberates carbon and nutrients from the complex material making up life forms-putting them back into biological circulation so they are available to plants and other organisms. The soil organisms that are responsible for most nutrient cycling are bacteria. Bacteria are unicellular, prokaryotic organisms that play very important roles as decomposers within an ecosystem.