Sustainable Management of Soils of Dryland Ecosystems of India for Enhancing Agronomic Productivity and Sequestering Carbon.

Abstract

Soil organic carbon (SOC) is a strong determinant of soil quality and crop productivity, especially in the arid and semiarid environments of the tropics. Drought stress, high temperatures reaching up to 45 C for 8–10 weeks in a year, coupled with low biomass productivity are common features of dry agroecosystems. India, with only 2.5% of the world’s geographical area, is a home to 17% of the global population. Population increased from 361 million in 1951 to 1140 million in 2011, more than threefold increase over 50 years. Productivity levels of rainfed dryland crops are far below those of global average. Thus, increasing productivity of rainfed cropping systems is an urgent task to meet the food demand of an ever-increasing population because 57% of the total arable land area of 141 Mha is under rainfed farming. Yields of important rainfed production systems in long-term manurial experiments under different climate and soil types show declining trends even with adoption of some recommended management practices (RMPs). Some RMPs include diverse crop rotations with legumes, and integrated nutrient management (INM) involving addition of farmyard manure (FYM), use of groundnut shells (GNS) and other crop residues (CRs), green leaf manuring (GLM), etc. These RMPs have been tested in seven long-term experiments of 13–27 years duration established in diverse soils and agroecoregions.