Effect of Herbicides and Fertilizer Levels on Weed Control and Nutrient Uptake by Wheat and Associated Weeds

Field investigations conducted at CCS Haryana Agriculturai University, Hisar during the winter seasons of 1990–91 and 1991–92 revealed that application of tribenuron at 7.5 g/ha+isoproturon at 1000g/ha controlled the weeds effectively and increased the grain yield significandy over the weedy check and other herbicide treatments. Application of nitrogen alone at 120kg/ha or with phosphorus or phosphorus + zinc did not exhibit any significant effect on the control of weeds, however, addition of phosphorus or phosphorus + zinc increased the yield compared to application of nitrogen alone. Weeds depleted 45.6, 11.3 and 45.6 kg/ha nitrogen, phosphonis and potassium, respectively when allowed to grow with the crop till the crop harvest, whereas the use of herbicides increased nutrients uptake by wheat and decreased nutrients uptake by weeds. The uptake of nutrients was higher by wheat and lower by weeds when higher dose of tribenuron or mixture of tribenuron and isoproturon was sprayed as compared to lower dose of tribenuron or the weedy check.