Effects of tillage systems on soil biodiversity

Abstract

Tillage affects the soil physical and chemical environment in which soil microorganisms live, thereby affecting their number, diversity and activity. Conservation tillage (CT) is practiced on 45 million ha world-wide, predominantly in North and South America but its uptake is also increasing in South Africa, Australia and other semi-arid areas of the world. It is primarily used as a means to protect soils from erosion and compaction, to conserve moisture and reduce production costs. In Europe, the area cultivated using minimum tillage is increasing primarily in an effort to reduce production costs, but also as a way of preventing soil erosion and retain soil moisture. Conservation tillage can improve soil structure and stability thereby facilitating better drainage and water holding capacity that reduces the extremes of waterlogging and drought. These improvements to soil structure also reduce the risk of runoff and pollution of surface waters with sediment, pesticides and nutrients. Reducing the intensity of soil cultivation lowers energy consumption and the emission of carbon dioxide, while carbon sequestration is raised though the increase in soil organic matter (SOM). Tillage-driven impacts on lumbricids and collembolans differed depending on soil texture, whereas those on nematodes and microbial communities varied depending on soil depth. Functional groups within certain taxa show differing tillage induced impacts. Linking several datasets on various indicator organisms clearly show that the decision on which tillage system should be applied must be taken for each individual case considering local soil characteristics.