Impact of Tillage and Herbicides on Weed Density, Yield and Quality of Cotton in Wheat Based Cropping System

Conservation tillage may improve yield of cotton in addition to improvement in soil quality if practiced for longer period. However, the practice may not be productive in short-term particularly when severe weeds are infesting the crops such as Cynodon dactylon, Conyza canadensis, Tribulus terrestris, and Cyperus rotundus, etc. Recent studies indicate that conventional tillage （CT） is more productive than zero tillage （ZT）/reduced tillage （RT）. Performance of cotton under three tillage systems, viz., ZT, RT and CT; and five herbicides, i.e., haloxyfop-R-methyl 10.8 EC （108 g a.i. ha^-1）, lactofen 24 EC （168 g a.i. ha^-1）, haloxyfop 10.8 EC ＋ lactofen 24 EC, hand weeding, and weedy check were evaluated during 2010-2011 at Gomal University, D.I.Khan, Pakistan, to explore the best management option for effective weed control, enhanced yield and quality of cotton grown after wheat. The results revealed that hand weeding and Haloxyfop as post emergence alone or in combination with Lactofen reduced weed density to the minimum irrespective of the tillage systems. Excessive rainfall and cooler temperature limited cotton growth and yield in 2010. The adverse weather conditions had more adverse effect on boll weight under ZT and RT than CT. Haloxyfop ＋ lactofen produced higher seed cotton yield in RT than ZT, however, it could not exceed CT. Broad-spectrum herbicides x CT produced the highest number of bolls/plant, boll weight and seed cotton yield. Fiber quality and net returns were also the highest in broad-spectrum herbicides x CT. In conclusion, broad-spectrum herbicides under CT were more productive in wheat based cropping system on silty clay soil of D.I.Khan.