Weed-crop competition effects on growth and yield of sugarcane planted using two methods

Effect of planting techniques and weed-crop competition periods on yield potential of spring planted sugarcane variety hsf-240 was studied at the ayub agricultural research institute,faisalabad,pakistan. the experiment was laid out in rcbd with a split-plot arrangement,with four replications and net plot size of 3.6m x 10m. in the experiment,two planting techniques viz.,60 cm apart rows in flat sowing technique and 120 cm apart rows in trench sowing technique were randomized in main plots. seven weed-crop competition periods viz.,zero (weed free),weed-crop competition for 45,60,75,90,105 days after sowing (das) and weedy check (full season weed- crop competition) were randomized in sub-plots. sugarcane sown by trench method exhibited more leaf area index (lai),average crop growth rate (acgr) and yield contributing attributes. trench sowing by yielding 72.22 and 75.08 t ha-1 stripped cane yields,significantly showed superiority over the flat sowing,which gave 64.13 and 66.04 t ha-1 stripped cane yields in 2005-06 and 2006-07,respectively. generally,there was an increase in weed population and biomass but decrease in leaf area index,crop growth rate and yield components with an increase in weed-crop competition period. a decrease of 10.06,17.90,22.42,28.65,37.64 and 56.89% in stripped cane yield was observed for weed-crop competition periods of 45,60,75,90,105 das and weedy check as compared with zero competition in 2005-06,respectively. in 2006-07,the respective decrease in stripped cane yield was 9.84,18.76,22.92,27.98,38.75,and 54.98%. trench sowing at 1.2 m row spacing proved better sowing technique and 45 das was the critical period of weed-crop competition.