Conservation Tillage Impact on Soil Aggregation, Organic Matter Turnover and Biodiversity

Abstract

Tillage is one of the oldest practices in agricultural production and offers many short term benefits in agro-ecosystem. These perceived benefits of tillage, however, have been gradually questioned because of its negative long-term consequences on soil and environment. Therefore conservation tillage systems have become the subject of intensive research among scientific communities and common practices among farming communities. However, scientific information on beneficial effects of conservation tillage systems on soil and environment is scattered. Critical analysis and synthesis of such information is helpful for scientific communities, farmers, students, and policy makers.This chapter reviews the impact of conservation tillage on soil organic matter, soil structure stability and soil organisms. Based on the analysis of available literature, it can be concluded that conservation tillage increases soil organic matter content. Most studies state that conservation tillage decreases the loss of carbon from the soil by reducing soil erosion loss and minimizing carbon loss by microbial respiration thus increasing soil organic matter. Some studies also found increased carbon input under conservation tillage system mainly through increased moisture and nutrient use efficiency of plants thereby increasing crop biomass production and its subsequent incorporation into the soil. Conservation tillage also enhances soil structural stability through its positive effects on soil moisture, organic matter and microbial activities. Accumulation of crop residues and organic matter in the surface layer under conservation tillage creates favourable feeding conditions and also provides physical protection to various soil organisms, thereby increasing their abundance as well as diversity. Various studies have shown that conservation tillage increases microbial biomass in soil from 80% to 200% as compared with conventional tillage system. Less soil disturbance, which is the characteristics of conservation tillage, has positive effects on soil properties, soil processes and soil organisms which interact in a complex way and together, they all enhance soil quality for agro-ecosystem productivity.