Biological fertility refers to the activities of soil organisms that improve plant growth. The biological fertility of soil provides us with great opportunities for land management and monitoring because of its dynamic nature. It is thought the biological state of soils may be able to provide early warning of land degradation, therefore enable us to employ more sustainable land management practices.
The biological components of soil perform a number of important processes, soil biological fertility :
- Soil organisms are most abundant in the surface layers of soil,
- Soil organic matter is necessary for nutrient cycling and soil aggregation,
- Maximum soil biological diversity depends on the diversity of organic matter and habitats,
- Nitrogen fixing bacteria form specific associations with legumes under specific conditions ,
- Nitrogen is released during organic matter breakdown, either into soil or into the soil microbial biomass,
- Arbuscular mycorrhizal fungi can increase phosphate uptake into plants in P-deficient soils,
- Soil amendments can alter the physical and chemical environment of soil organisms,
- Some crop rotations and tillage practices decrease the suitability of soil for plant pathogens,
- Production systems based on soil biological fertility can be profitable,
- Soil biological processes develop slowly, and the time required will differ for different soils, environments and land management practices.