The breakdown of plant leftovers and the release of nutrients for the plants are accelerated by soil enzymes. The substrate is the material on which soil enzymes function. For instance, glucosides, a substance frequently present in plants, are broken down into glucose by soil enzymes called glucosidases. Enzymes have active sites that bind to the substrate to create a transient complex, and they are substrate-specific. A result of the enzymatic process may be a nutrient present in the substrate. Living and dead organisms, plant roots and wastes, and soil animals are all sources of soil enzymes. Enzymes that have been stabilised in the soil matrix accumulate or form complexes with humus from humus-organic materials.

Despite being a complicated process, it is no longer connected to living cells. Since 40% to 60% of enzyme activity is thought to come from stable enzymes, activity is not necessarily significantly associated with microbial biomass or respiration. The result of ongoing microbial activity and viable population activity at the moment of sampling is enzyme activity. Dehydrogenase, for instance, theoretically exists only in live cells and cannot exist in stable soil complexes and is an example of an enzyme that only reflects the activity of living cells. Long before other changes in soil quality indicators are noticed, enzymes react to changes in soil management. In the nitrogen cycle and the breakdown of organic matter, soil enzymes are crucial.

Some enzymes, such as hydrolases and glucosidases, are only involved in the breakdown of organic materials, whereas others help to mineralize nutrients (eg-amidases, ureases, phosphatases, sulfates). There isn't any conclusive proof that enzyme activity is correlated with food availability or plant growth, with the exception of phosphatase activity. Given that the action of the enzymes can result in the mineralization of the nutrients accessible to plants, this relationship may be indirect.

Agricultural methods that lessen soil degradation and increase agricultural sustainability are needed for tropical and subtropical soils. When used with crop rotation, no-tillage causes little soil harm and can accomplish these objectives. The presence of soil enzymes can reveal information on how soil management influences soil processes including nitrogen cycling and degradation. In a split-plot experiment on soil enzyme activity, crop rotation and conventional tillage separate the main plot. In 1976, the experiment was started in southern Brazil. Between soil enzyme activity and total organic carbon and nitrogen microbial biomass, there was a strong link. All of these point to the fact that nitrogenous transaminase promotes microbial activity and that soil enzyme activity is a sensitive indication of controlled soil quality changes.

In a wide range of environmental and ecosystem management applications, soil enzyme tests have become a useful technical instrument. Long before detectable changes in the total organic carbon content take place, several enzymes have demonstrated the ability to reflect early changes in soil quality brought on by soil management. It might serve as a roadmap for managing ecosystems sustainably over the long run. In severely disturbed landscapes, the enzyme assay can gauge the extent of soil deterioration and recovery.

Enzyme activity testing reflects the bioavailability of specific heavy metals in soil. Certain contaminants in the soil have been demonstrated to be broken down by enzymes stabilised on the colloidal surface and integrated into the soil. Understanding the ecology and role of extracellular enzymes in the soil requires a lot of knowledge due to the physical and chemical makeup of the soil as well as the diversity and complexity of microbial communities. The use of enzyme technology necessitates careful interpretation and implementation, in part because of this. This is especially true when evaluating soil quality because it's necessary to combine soil enzyme activity with other crucial soil metrics.