Study of Critical Crop-Weed Competition Period on Quality Characters of Soybean

The present experiment was conducted at Instructional Cum Research Farm, Department of Agronomy, IGKV, Raipur (C.G.) during Kharif season (July to October) of 2009 to find out the critical crop-weed competition period in soybean. The fourteen different levels of weed competition practices comprises of seven weed free conditions and seven weedy conditions were laid out in Factorial Randomized Block Design (RBD) with three replications. Soybean variety “JS-93-05” was grown as a test crop. Soybean was planted on 08^th July, 2009 with spacing 30 x 10 cm. The crop was fertilized with 20, 60 and 30 kg N, P₂O₅ and K₂O ha⁻¹, respectively. The soil of experimental field was low in nitrogen, medium in phosphorus and high in potash with neutral in reaction. The result of experiment indicated that among the quality content of soybean, weed free upto 5^th week and weedy condition upto 1^st and 2^nd week has little effect on oil content and oil yield and found to be similar as in weed free check but in case of protein content weed free upto 6^th week found prominent effect. In experimental field, Echinocloa colonum, Parthenium hysterophorus, Cyperus rotundus, Cynodon dactylon, Brachiaria ramosa, Euphorbia species, Alternathra species and some other weeds were dominant and observed throughout the crop season. Weed free upto 4^th week was most appropriate for reducing weed density, weed dry matter and weed growth rate, whereas highest weed control efficiency was recorded under weed free from 5^th week.