Soil Enzymes and Their Role in Nutrient Cycling

Soil is a dynamic living non-renewable resource that acts as an interface between agriculture and environment. Soil enzymes play critical role in soil processes ranging from biochemical reactions in plants, animals, and microbes to decomposition of organic matter, soil structure stabilization and nutrients cycling. Different microbes and enzymes are involved in cycling of carbon (C), nitrogen (N), phosphorus (P), and sulfur (S) in an ecosystem. The nutrient cycles function as a result of biological and physico-chemical reactions in soil. The nutrients cycling in an ecosystem are primarily governed by soil microbes and enzyme activities. The biochemical reactions of these cycles are accomplished by enzymes such as amidases, arylsulphatase, cellulases, dehydrogenase, glucosidases, laccase, phosphatases, and urease. These enzymes serve as biological indicators that help to identify variations in soil physical, chemical, and biological properties. Enzymes respond faster to soil management practices long before other soil quality indicator changes are detectable and their method of detection is simple, easy, and quick. In this chapter, we will discuss about the major enzymes involved in the cycling of C, N, P, S, and their mechanisms of action, role in maintaining soil health and factors that affect their activities in soil.