Soil microbiological activity depending on tillage system and crop rotation
Institute of Soil and Plant Sciences, Faculty of Agriculture, Latvia University of Agriculture, Liela iela 2, LV-3001 Jelgava, Latvia
Soil management practices include various tillage systems that influence plant growth and activity of microorganisms. Minimum tillage without soil inversion is increasingly being used because the conventional soil tillage with soil inversion is a more energy-consuming operation and affects the biodiversity of agroecosystems. The present study was aimed to estimate the effect of conventional and minimum tillage systems on soil microbiological activity. The trials were established in the experimental fields of the Latvia University of Agriculture. The intensity of soil respiration and the ratio of microbial biomass between minimum tillage and conventional tillage were calculated from 2011 to 2013, and cellulose degradation intensity – from 2012 to 2014. The conventionally tilled plots were ploughed to the depth of 23 cm, but minimum tillage was done at the depth of 10–12 cm without soil inversion. Soil samples were collected at two depths: 0–10 cm, and 11–20 cm. The crops were cultivated both in a monoculture (winter wheat) and using crop rotation (winter wheat–rape). Soil microbiological activity was characterised by soil respiration, cellulose degradation intensity, and biomass of soil microorganisms. The results suggest that microbial biomass of soil increased in the fields under minimum tillage compared to those under conventional tillage. It was found that crop rotation had no significant effect on the microbial biomass and soil respiration intensity. Although the upper soil layer has a higher potential of microbiological activity, the cellulose degradation intensity showed a tendency to decrease at both soil depths in the experimental plots without crop rotation.