Nitrogen fertilizer levels and some weed control treatments effects on barley and associated weeds

摘要

Studies were carried out to investigate the efficiency of nitrogen fertilizer levels (15, 30, 45 and60 kg/fed) and different postemergence herbicides (metosulam, sulfamoylurea, fenoxaprop-pethyl,clodinafop-propargyl, isoproturon + diflufinican and isoproturon), hand weeding andunweeded check in barley crop at private farms in Shalakan, Kalubia Governorate, Egypt during2007/2008 and 2008/2009 seasons. Increasing N- levels from 15 to 30, 45 and 60 kg /fedsignificantly increased number and dry weight of barley weeds after 60 and 90 days from sowing(DFS). Application of 60 kg N/fed recorded the highest number and dry weight of weeds.Metosulam at 0.04 L/fed provided control (95.46 - 92.83% reduction in dry weight after 60 and 90DFS) for broadleaved weeds but failed to completely control narrow-leaved weeds. Clodinafoppropargylat 140 g/fed provided 94.85 and 94.34 % reduction in dry weight after 60 and 90 DFSof narrow leaf weeds. Isoproturon + diflufinican came in the first order for controlling total weedsbut statistically leveled with isoproturon alone. It recoded number and dry weight of total weedsthan unweeded by 90.31 and 91.46 % after 60 days from sowing and 89.78 and 90.80 % after 90days from sowing. pplication of nitrogen at 60 kg N/fed recorded the highest value of flag leafarea, plant height, spike length, number of grains/spike, grains weight /spike, spikes number /m2,straw and grain yields as well as grain protein and total carbohydrates percentage. All herbicidaltreatments and hand weeding increased significantly growth, yield, yield components andchemical composition of grain barley. Isoproturon + diflufinican was superior treatment forincreasing plant height, spike length, grains number /spike, grains weight /spike, spikes number/m2, straw and grain yields as well as grain protein and total carbohydrates percentage. While,hand weeding recorded the highest values of flag leaf area. Application of isoproturon +diflufinican herbicide provided 66.3 % more grain yield than weedy check. The interactionbetween N-levels and weed management treatments had significant effect on total dry weight ofweeds, spikes number /m2, grain weight /spike and grain and straw yields. Isoproturon +diflufinican produced the lowest values of total dry weight of weeds after 60 and 90 DFS when 15kg N/fed was added. While, Application of 60 kg N/fed gave the maximum values of number ofspike /m2, weight of grain /spike, grain and straw yields/fed when isoproturon + diflufinicantreatment was applied. It could be concluded that using 60 kg N/fed resulted in increment ofgrowth and productivity of barley crop when isoproturon + diflufinican treatment was used.