Effects of sowing date, tillage and residue management on productivity of cotton (Gossypium hirsutum L.) wheat (Triticum aestivum L.) system in northwest India

In southwestern region of Punjab in north India, sowing dates of cotton crop in cotton (Gossypium hirsutum L.)-wheat (Triticum aestivum L.) system are staggered from last week of April to mid of May depending upon the surface water supply from canal as,ground water is not fit for irrigation. Further, farmers practice intensive cultivation for seedbed preparation and burning of wheat straw before sowing of cotton crop. With the present farmers' practices, yields have become static and system has become non-profitable. Field experiments were conducted on Entisols for two rotations of cotton-wheat system during the years of 2004-2005 and 2005-2006 in split plot design to study the direct and interactive effects of date of sowing and tillage-plus-wheat residue management practices on growth and yield of cotton and wheat and to increase the profitability by reducing the tillage operations, which costs about 50% of the sowing cost. The pooled analysis showed that in cotton crop, there was a significant interaction between year x dates of sowing. Among different tillage-plus-wheat residue management practices yields were 23-39% higher in tillage treatments than minimum-tillage. In wheat, grain yield in tillage treatments were at par. Water productivity amongst the tillage treatments in cotton was 19-27% less in minimum tillage than others tillage treatments. Similar trend was found in wheat crop. Remunerability of the cotton-wheat system was more with a combination of reduced tillage in cotton and minimum tillage in wheat than conventional tillage. (C) 2008 Elsevier B.V. All rights reserved.