Saxena, S.C.Nainwal, Rakesh Chandra2016-09-202016-09-202010-08http://krishikosh.egranth.ac.in/handle/1/77719Thesis-PhDA field experiment was conducted to evaluate the weed control treatments on growth, yield and quality of soybean during the ‘kharif’ 2008 and 2009, at N. E. Borlaug Crop Research Centre of G.B. Pant Univ. of Agriculture and Technology, Pantnagar (U.S. Nagar). Ten weed control treatments were tested in randomized block design with four replications, pendimethalin and diclosulam were sprayed on the day after sowing the crop as pre emergence application. Fluchloralin was incorporated into the soil before planting the crop. Haloxyfop was applied at 21 DAS as post emergence. Soybean variety PS 1347 was sown on July 10 and August 1 was harvested on November 12 and 14 during 2008 and 2009, respectively. Seed @ 75 kg seed ha-1 were sown in rows 45 cm apart. The experimental field was predominately infested with Echinochloa colona, Celosia argentia, Cyperus rotundas weed species which constituted a major part and remained dominant in weedy check plots throughout the crop growth. Diclosulam either alone at higher rate or supplemented with HW 20 DAS or combined with haloxyfop effectively controlled the both type of weeds (mono and dicot). However, haloxyfop applied as post emergence could only control the monocot weeds. The highest weed control efficiency and the lowest weed biomass were recorded in weed-free treatment followed by application of diclosulam 18g ha-1 supplemented with HW at 20 DAS. Application of diclosulam as pre-emergence also performed better over the standard check either applied pendimethalin as pre- or pre-plant incorporation of fluchloralin before the sowing of the seed. All the weed control treatments resulted in to higher physiological growth parameters viz. CGR, RGR, NAR, LAI and LAR as compared to weedy check. Weed free recorded the highest value of protein and oil content during both years. Different weed control treatments significantly affected the fatty acid composition of the soybean seed. Among the different herbicide, the highest seed yield was recorded with application of diclosulam supplemented with HW at 20 DAS and application of diclosulam followed by haloxyfop.enhaloxyfop, herbicides, weed control, soyabeans, Glycine maxThesis