Biological Properties of Soil
Soil Respiration
Soil respiration is a measure of the metabolic activity of the soil microbial community. Soil respiration is a measure of the carbon dioxide released from soil. It is released as a result of decomposition of soil organic matter and plant litter by soil microbes and through plant roots and soil fauna. Thus, it is an important indicator of soil health because it measures the level of microbial activity and the content and decomposition of soil organic matter. It also reflects the condition of the physical and chemical environment of a soil.
Conditions Affecting Soil Respiration
Soil respiration rates are also dependent on dynamic soil factors, including soil organic matter content, pH, temperature, and moisture. Practices that leave crop residue on the soil surface, using no-till cropping systems, growing cover crops and high-residue crops, and using other practices that add organic matter to the soil, usually promote soil respiration. Organic matter provides the food or substrate on which heterotrophic soil microbes feed. Organic materials with low carbon to nitrogen (C:N) ratios (e.g. manure, soybean residue) are easily decomposed; thus, the addition of these materials to soil will increase soil respiration. Materials with high C:N ratios (e.g., compost, wheat straw) decompose more slowly will decrease soil respiration but provide a more stable, long-term supply of organic material.
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