Influence of integrated weed management practices on weed competition for nutrients in wheat

A field experiment was conducted during the winter seasons of 1995–96 and 1996–97 to study the effect of herbicides m conjunction with cultural practices (viz. stale seed bed, normal seed bed, normal seed bed plus triallate 1.00 kg/ha) on wheat. The major weeds were Phalaris minor, Lalium temulentum, Avena fatua and Vicia saliva. Uncontrolled weed growth, depleted 83.4, 18.7 and 80.8 kg/ha of nitrogen, phosphorus and potassium, respectively which was 47.1, 11.5 and 55.21 kg/ha higher than the total uptake of these nutrients by wheat crop. NPK depletion by P. Minor and L. temulentum was significantly lower in stale seed bed and normal seed bed + triallate 1.0 kg/ha. However, NPK depletion by A. fatua in normal seed bed + triallate was significantly lower as compared to stale seed bed. Integration of stale seed bed or normal seed bed + triallate with lsoproturon + surfactant and dichlofop-methyl + surfactant reduced weed dry weight and NPK depletion by weeds and increased grain yield and NPK uptake by wheat crop. Stale seed bed in conjunction with isoproturon + surfactant and dichlofop + surfactant effected increase in wheat grain yield by 113.8 and 1 17.4%, respectively over unweeded normal seed bed.