Effect of organic fertilization systems on the enzymatic activity of sod-podzolic soil

Abstract

The study of soil enzymatic activity is an important tool for assessing its ecological condition and fertility, as enzymes serve as sensitive indicators of biological processes involved in the transformation of organic matter. This is especially relevant for sod-podzolic soils of the Western Polissia region, which are characterized by low humus content, increased acidity, and unstable nutrient regimes. Optimizing fertilization systems under such conditions is one of the key tasks for ensuring sustainable agriculture. The article presents the results of studying the effect of different fertilization systems (manure, green manure crops, and their combination) on the activity of the main soil enzymes—dehydrogenase, polyphenol oxidase, and invertase. The research was conducted in a long-term field experiment established in 1990 at the Volyn State Agricultural Research Station of the Institute of Agriculture of the Western Polissia of NAAS of Ukraine. After the second reconstruction, the crop rotation includes four crops: annual grasses, winter rye, silage maize, and oats. Enzyme activity was determined using standardized methods (DSTU 7928:2015, DSTU 7929:2015, Haziev’s method). The results showed that the overall level of enzymatic activity in sod-podzolic soil remains relatively low; however, the combination of manure and green manure crops contributed to the highest enzymatic activity values. This indicates the activation of microbiological and humification processes, an enhanced cycle of organic matter, and changes in the biological properties of the soil. The obtained results confirm the importance of combined use of organic fertilizers and green manure crops for improving biological activity and increasing soil fertility in the Polissia region.