Effect of residue recycling on biological soil health indicators and surface CO2 emissions in rainfed semi-arid tropical Alfisol under minimum tillage conditions

Abstract

The present study was undertaken to assess the impact of surface application of different levels of crop residue on predominant biological soil health indicators and release of CO2 fluxes from the surface soil as a result of microbial respiration under minimum tillage conditions. The experiment was conducted in a rainfed Semi-Arid Tropical (SAT) Alfisol at Hayathnagar Research Farm of Central Research Institute for Dryland Agriculture, Hyderabad. Studies indicated that an application of 6 t ha-1 of sorghumstover recorded significantly highest microbial biomass carbon of 177.11 and 167.83 μg g-1 of soil andhighest DHA (Dehydrogenase Assay) of 2.49 and 1.74 μg TPF g-1 hr-1 at surface and subsurface layers respectively. Similarly, the activity of arylsulphatase was also significantly influenced by residue application and was highest at 6 t ha-1 plot (150.755 μg PNP g-1 hr-1) irrespective of soil depth. The activities of othersoil enzymes such as urease, acid phosphatase and alkaline phosphatase were also significantly influenced at both the soil depths by graded levels of residue applications. On an average, quantitatively, biological soil quality indicators attained higher values in surface soil compared to subsurface soils. The CO2 flux significantly increased with the increasing levels of surface applied sorghum crop residue upto 4t ha -1 under minimum tillage conditions. Thus, the biological soil quality indicators were significantly influenced with residue application under minimum tillage in these Alfisols.