Title: Soil Organic Carbon, Carbon Sequestration, Soil Microbial Biomass Carbon and Nitrogen and Soil Enzymatic Activity as Influenced by Conservation Agriculture in Pigeonpea and Soybean Intercropping System
Abstract: Field experiments were conducted during the year 2014-15 and 2015-16 at Conservation Agriculture Project plot, MARS, Dharwad, Karnataka to study the influence of conservation tillage, land configuration and residue management practices on soil health in a pigeonpea + soybean intercropping system. The experiment consisted of 6 tillage systems [CT1: Conservation tillage with BBF and crop residue retained on the surface, CT2: Conservation tillage with BBF and incorporation of crop residue, CT3: Conservation tillage with flatbed with crop residue retained on the surface, CT4: Conservation tillage with flatbed with incorporation of crop residue, CT5: Conventional tillage with incorporation of crop residue and CT6: Conventional tillage without crop residue]. The experiment laid out in strip block design and replicated thrice. The conservation treatments were found to significantly improve soil health. The pooled data revealed that, all the conservation tillage systems i.e. CT1, CT2, CT3 and CT4 recorded significantly higher soil organic carbon at 0-15 cm depth (0.62, 0.64,060 ad 0.62 %, respectively) and 15-30 cm depth (0.56, 0.56, 0.54 and 0.55 %, respectively), higher soil carbon sequestration (15.07, 15.39, 14.58 and 14.72 t ha-1, respectively) over conventional systems. However, biological soil quality such as soil microbial biomass carbon and nitrogen were significantly higher in all the tillage systems except conventional tillage without crop residue. While, significantly higher soil urease activity (11.76, 11.86, 11.10 and 11.44 µg NH4-N g-1 day-1), dehydrogenase activity (32.29, 32.29, 31.14 and 31.55 µg TPF g-1 day-1) and total phosphatase activity (173.21, 174.55, 170.09 and 173.21 µg PNP g-1hr-1) were recorded in CT1, CT2, CT3 and CT4 over CT5 and CT6.