The influence of type and dosage of exogenous organic matter on chosen biochemical soil properties

Organic matter in soil is exposed to decomposition and other changes, and excessive loss of such matter is one of the most serious forms of degradation. One of the possible solutions to this problem is the application of various types of organic matter. These include exogenous organic matter (EOM), which originates, to a large extent, outside the agro-ecosystem. The aim of the presented research was to evaluate the influence of type and dosage of applied EOM on soil characteristics, specifically on the activity of selected soil enzymes which can respond quite sensitively to changes in land management as well as changes in environmental conditions. Nitrogen was supplied to the soil in a combination of organic and mineral fertilizers: in variants from 0-100% in various types of EOM, and 0-100% in mineral form respectively, with a resulting dosage of 200 kg N/ha. Enzymes from the N, P and C cycles were chosen for evaluation of the influence of EOM on enzyme activity, focusing on the activity of urease, phosphatase and cellulase. In the research it was proven that application of EOM leads to relatively rapid changes in enzyme activity. Soil micro-organisms, and the processes they control, showed varying sensitivity to EOM application. Enzyme activity (cellulase, acid and alkaline phosphatase) was generally stimulated by the highest dosage of the tested EOM. This was not statistically confirmed in the case of urease activity. The research also confirmed that the decisive factor for cellulase, acid and alkaline phosphatase activity was the amount of carbon, nitrogen and phosphorus supplied via EOM. The ratio of C : N in the applied EOM had an influence on the activity of urease and a slight dependence was proven in cellulase activity and acid phosphatase activity.