Productivity, Organic Carbon and Residual Soil Fertility of Pigeonpea–Wheat Cropping System Under Varying Tillage and Residue Management

Abstract

Conservation agriculture improves productivity and soil quality, but most of the research results are only confined to the rice–wheat system. Hence, a long term field experiment was conducted at Indian Agricultural Research Institute, New Delhi during 2008–2009 to 2011–2012 on a sandy loam soil to study the effect of tillage and crop establishment techniques, and residue management practices on system productivity, residual nutrient status, microbial biomass carbon, microbial biomass nitrogen and enzymatic activities under a pigeonpea–wheat cropping system. It was observed that zero tillage gave 5.4 and 2.3 % higher pigeonpea and wheat yield, respectively, over conventional tillage. Similarly, it resulted in 9.6 and 4.9 % higher Kjeldahl N and extractable K, respectively and the plots under zero tillage had 20.6, 8.0 and 6.1 % higher dehydrogenase and acid and alkaline phosphatase activities, respectively, over conventional tillage. Application of crop residue at 3 t/ha provided 14.3 and 34.4 % higher pigeonpea and wheat grain yield, respectively, over no residue. Further, organic C, Kjeldahl N and Olsen’s P in soil were enhanced by 7.4, 6.9 and 7.5 %, respectively, due to residue compared to no residue plots. Combined application of pigeonpea + wheat residue at 3 t/ha resulted in higher dehydrogenase (20.9 µg triphenylformazan/g/h), β-glucosidase (145 µg p-nitrophenol/g/h), and acid phosphatase activities (24.5 µg p-nitrophenol/g/h) than the single application of wheat or pigeonpea residue in either season or no residue control.