Short-term effects of tillage and residue management following cotton on grain yield and quality of wheat

Grain yield and quality of winter wheat (Triticum durum L) are affected by several factors, and crop management has a very important role among them. A 3-year (from 2003-04 to 2005-06) field experiment under irrigation was carried out at Diyabakir in the South East Anatolia Region of Turkey to evaluate immediate effects of tillage and residue management systems after cotton (Gossypium hirsutum L.) on grain yield and quality [thousand grain weight (TGW), test weight (TW), protein content (PC) and mini sedimentation (mini SDS)] of durum wheat, and correlations among these parameters. A split plot design with three replications was used, in which two residue management treatments [collecting and removing cotton stalks from plots (S-Rem), and chopping and leaving of cotton stalks in plots (S-Lev)] were main plots, and six tillage and/or wheat planting method combination treatments [moldboard plough + cultivator + broadcast seeding + cultivator as conventional tillage-I (CT-I), moldboard plough + cultivator + drill as conventional tillage-II (CT-II), chisel plough + cultivator + drill as vertical tillage (VT), two passes of disk harrow + drill as reduced tillage-I (RT-I), rotary tiller + drill as reduced tillage-II (RT-II), and no-till ridge planting (RP)] were sub-plots. The effect of cotton residue management on grain yield, TW, PC, mini SDS was not significant, but S-Rem (51.21 g) gave significantly higher TGW than S-Lev (50.63 g). Tillage and/or wheat planting method combination treatments had a significant effect on grain yield. TGW and TW, but did not significantly influence PC and mini SDS. Conventional tillage with broadcast seeding (CT-I) treatment produced the lowest wheat grain yield (5.395 Mg ha(-1)), while there were no significant differences in grain yield among the other five tillage treatments (yields ranged from 5.671 to 5.819 Mg ha(-1)). In spite of supplemental irrigations, the variability of weather conditions, particularly the amount and distribution of rainfall during the growing season, had a significant influence on wheat grain yield and quality parameters (TGW, TW, PC, mini SDS). Grain yield had a significant positive correlation with TGW, but it did not show any relationship with other grain quality parameters. In conclusion, the findings suggest that conventional tillage with broadcast seeding would be less effective in producing grain yield of wheat compared to other five tillage treatments with row planting, while management of the previous cotton stalks may not have any effect on yield and quality of wheat except TGW. (C) 2010 Elsevier B.V. All rights reserved.