Relations of enzyme activities with different fractions of soil organic matter
2009
Mikhailouskaya, N., Research Institute of Soil Science and Agrochemistry, Minsk (Belarus) | Bogdevitch, I., Research Institute of Soil Science and Agrochemistry, Minsk (Belarus)
Stabilization and maintenance of extracellular enzymes activity in soil is important ecological function of humic substances. Enzymes catalyze all biochemical reactions and are an integral part of nutrient cycling in the soil. Stable humus pool and humus-enzyme complexes are of great importance in soil fertility. Humus-enzyme complexes functioning in soil suggests the possibility to reveal enzymatic indicators of soil quality. Specific hydrolytic enzymes (cellulose and invertase) and oxidases (peroxidase and polyphenoloxidase) were tested because they are linked to carbon cycle. The aid of investigation was the assessment of relationships between enzymes activities and the contents of different fraction of SOM in Albeluvisol loamy sand soil. Humus parameter (Tyurin method) was used for characterization of stable SOM. Decomposable part of SOM was determined by measurement of Chwe content in soil. However the decomposable part of SOM is important in the evaluation of the farming systems sustainability it is less appropriate for soil quality diagnostic. Stable organic matter may be more appropriate to indicate the quality of a soil ecosystem. For the development of reliable biochemical parameters for soil quality diagnostic the enzyme interrelationships with different fractions of soil organic matter were studied. It was concluded that the activity of enzymes, which is closely correlated with humus and weakly related to decomposable SOM, are more appropriate for specific biochemical tests in the definition of soil quality. Ligninolytic enzymes peroxidase and polyphenoloxidase are adequate for this purpose in a greater degree unlike hydrolytic enzymes cellulose and invertase. Hydrolytic enzymes activities were related closely with humus and Chwe contents as well. Simplicity of the assay is one of advantages of proposed biochemical indicators as well.
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