Department of Soil Science, College of Agriculture, G.B. Pant University of Agriculture and Technology, Pantnagar, Distt. U. S. Nagar, Uttaranchal, 263145.
*Corresponding author: (E-mail: rptripathi@indiatimes.com)
A field experiment was conducted during 1999–2002 to evaluate tillage-induced changes in soil physical properties and yield of rice and wheat in rotation. Tillage treatments for rice were puddling by 4 passes of rotary puddler (PR), reduced puddling by 2 passes of rotary puddler (ReP), conventional puddling (CP), direct seeding without puddling (DSWP) and those for wheat were zero tillage (ZT) and conventional tillage (CT) superimposed over the rice tillage treatments. Puddling index was 1.23 and 1.2 times higher in PR and CP plots than in the ReP plots. Cracking after rice harvesting increased with degree of puddling. Among the puddled plots, crack volume was lowest in the ReP plots. Among the puddling treatments, plasticity index was lowest in the ReP plots and highest in the PR plots. Effect of wheat tillage (ZT and CT) on plasticity index was non-significant. Among the puddled plots, bulk density measured at 30 days after transplanting and at harvesting was highest in the PR plots and lowest in the ReP plots. Influence of wheat tillage (ZT and CT) on bulk density was non-significant. Compared to the DSWP plot infiltration rate reduced 2.3 times at 30 DAT and 2.8 times at harvesting in PR plots and 1.1 times at 30 DAT and 1.3 times at harvesting in ReP plots due to puddling. Rice yield was maximum in PR plots but was statistically equal to those in ReP plots, and wheat yield was minimum in PR plots and maximum in DSWP plots. The total grain yield (rice + wheat) was highest (9447 kg ha−1) in the ReP plots of rice under ZT for wheat. The ReP condition for rice and ZT for wheat not only optimized yield but also caused minimum deterioration of soil structure.
Reduced tillage, zero tillage, puddling index, plasticity index
