Soil microbial communities and dehydrogenase activity depending on farming systems

The aim of study was to compare the effect of farming methods on soil microbial communities and dehydrogenase activity (DHA). During 2008-2013, in the five-field crop rotation the following treatments were carried out: ORG - organic; ORGFYM - organic with cattle manure; CONFYM - conventional (cattle manure, mineral fertilizers and pesticides were used). From the treatments soil samples in three replicates were taken for microbiological tests in September yearly. Total bacteria and cellulose decomposing bacteria were determined as a number of colony forming units per g of dry soil. Soil DHA was determined in accordance with Tabatabai (1982). Solid cattle manure applied in the ORGFYM rotation increased significantly (P < 0.05) the number of total bacteria and cellulose decomposing bacteria (by 19.4% and 45.3%, respectively), and DHA by 22.7%. There appeared no clear and significant differences in effects between ORGFYM and CONFYM treatments, as an average of experiment period. In some cases, the use of certain pesticides in CONFYM treatment significantly affected the microbe numbers and soil DHA.