Microbial abundance and activity in chernozem under different cropping systems

The study monitored microbial abundance and dehydrogenase activity in chernozem soil under different cropping systems. Soil samples were taken from the long-term trials Crop Rotations and IOSDV, at the Rimski Sancevi experimental field of the Institute of Field and Vegetable Crops. The soil samples were collected in two years from ten cropping systems at three sampling depths. Number of the examined microbial groups was assessed by the indirect dilution method, while dehydrogenase enzyme activity was measured spectrophotometrically. Number of the tested microbial groups and dehydrogenase activity varied significantly depending on the cropping system and year of study, while sampling depth significantly affected enzyme activity. The highest number of microorganisms was obtained in non-agricultural soil and unfertilized soil under 2-year and 3-year rotation, while the highest dehydrogenase activity was recorded in non-agricultural soil and soil under wheat grown in monoculture.