Despite best practices, an estimated 40% to 50% of applied nitrogen is unavailable to the crop due to immobilisation by soil microorganisms or loss from the soil through denitrification or leaching. Although some soil microorganisms contribute to this nitrogen loss or immobilisation in the soil, others can enhance the availability or stability of nitrogen in the soil or even improve root growth and physiological functions, all of which can have a positive influence on nitrogen use efficiency.
The soil is a living environment, full of organisms that influence plant growth and health. These organisms include visible inhabitants like earthworms, as well as a multitude of invisible, microscopic inhabitants like bacteria and fungi. Plants—through their growing roots—are also part of this living environment. Many of the interactions among these inhabitants occur through biochemical signalling, particularly in the rhizosphere.
Soil microbes and the biochemical compounds they make play a major role in nutrient release and nutrient use efficiency.