The varying effect of water erosion on chemical and biochemical soil properties in different parts of Chernozem slopes

Abstract

In recent decades erosion processes have influenced agricultural soil quality worldwide. In the Czech Republic the situation is made even worse by the fact that, in the post-war period, considerable changes occurred in land use during collectivisation of farm land, along with a significant increase in the average size of farmed plots. This led us to observe the changes in chemical and biochemical soil properties in the intensively farmed Chernozem region of south Moravia. According to the erosion/deposition model, 48 localities with erosional, depositional and control areas were chosen where soil samples were then taken from among maize crops. These samples were then analysed and the results were statistically processed. From the results of analysis of chemical properties relating to basic nutrients and soil organic matter, it is apparent that, in depositional areas of slopes, supplies of potassium and phosphorus were higher in comparison with erosional areas. The opposite trend was evident in calcium, where statistically significant higher levels were found in erosional areas of slopes, which is linked to the chemistry of soil-forming substrate. This trend also influenced pH. Differences were also found in characteristics relating to soil organic matter. Overall carbon and nitrogen content was significantly higher in depositional areas. There was a statistically conclusive difference in quality of organic matter in these areas expressed by the carbon content of humus matter, carbon in humic acids and the C:N ratio. The content and quality of organic matter influence biological and biochemical soil properties. In enzymes there was statistically higher activity of dehydrogenase, acid phosphatase, urease and nitrate reductase in depositional areas compared with erosional areas.The results obtained indicate considerable differences in soil properties within individual plots of land, especially between erosional and depositional areas of slopes, and the conclusions of the study are applicable in planning anti-erosion defences and management measures in agro-ecosystems.