Nutrient Competition Studies in Cotton (Gossjrpium Hirsutum L.) under Different Weed Control Systems in Madhya Pradesh*

Competition for mineral nutrients, mainly for N, P and K between the economic crops and associated weeds influences’ the yield adversely. Studies to estimate the magnitude 6f>such losses, occurring particularly in Gottori (Gassypium hirsutum (L.) in relation to the conventional, chemical and integrated systems of weed'Control Were carried out at two locations, Indore and Khandwa during 1976–77 and 1977–78: Data oh nutrient (NPK) removal in the tissues of weeds and crop components revealed that the crop was deprived of 5C0 to 800 percent of N, P and K, resulting in strikingly poor yields in unweeded conditions. Weeds were effectively controlled by the conventional system yet diuron (3-(3,4-dichlorophenyl)-1, 1-dimethylurea) 0.75 kg/ha as preemergence supplemented either with diuron 0.5 kg/MSMA (monosodium methanearsonate) 1.5 kg/ha as post-emergence in chemical system or with interculture in integrated system were outstanding. Boch fiuchloralin (N-propyl-N-(2, chloroethyl)-2, 6-dinitro-n-trifluoromethyl-aniline) and penoxalin (N-Cl-ethyl-propyl)-3, 4-dimethyl-2, 6-dinitrobenezenamine) as preplanting incorporated herbicides had restricted advantages particularly in medium soils of Indore. Band application of diuron or objective hand weeding as measures to curtail weeding budget, were promising only in light soils of Khandwa.