Influence of tillage and crop residue on soil physical properties and yields of rice and wheat under shallow water table conditions

An experiment was conducted to evaluate the effects of tillage and residue incorporation on soil properties and yields of rice (Oryza sativa L.) and wheat (Triticum aestivum L.) in rotation for 4 years on a silty clay loam of an Aquic Hapludoll with natural water table fluctuating between 0.05 and 0.97 m depth The rice experiment was laid out in split plot design with four levels of tillage, viz. conventional puddling (CP), puddling by four passes of rotavator (PR), reduced puddling by two passes of rotavator (ReP), and direct seeding without puddling (DSWP) and two levels of residue, viz. residue incorporation (RI) and residue removal (RR) in four replications. The treatments for wheat were zero tillage (ZT) and conventional tillage (CT) with RI and RR superimposed over the plots of rice. Tillage for rice increased puddling index and bulk density (BD) over the years. The increase was significantly higher in CP and PR than in ReP. In wheat season, BD was higher under ZT than under CT but the differences were not significant. Puddling decreased saturated hydraulic conductivity with time, which became significantly lower in CP and PR in the fourth year than in ReP in the first year. Infiltration rate (IR) also decreased with time and was lowest in CP and PR. In wheat season, IR was at par under ZT and CT. Rice yield in PR was maximum and at par with that in Rep. But wheat yield was lowest in PR and highest in DSWP, and was at par in DSWP and ReP. Thus, rice yields were optimum under ReP, in which changes in soil properties were least, and wheat yields were optimum both under ZT and CT in the DSWP and ReP plots of rice under shallow water table conditions of the silty clay loam. (c) 2006 Elsevier B.V. All rights reserved.