Influence of Nitrogen and Substituted Urea Herbicides on the uptake of N, P and K by Phalaris minor Retz. and Wheat¹

In field studies conducted during 1980–81 and 1981–82 it was observed that higher levels of nitrogen to wheat and the herbicide treatments for control of Phalaris minor Retz. (isoproturon 0.94 kg. metoxuron 1,5 kg and methabenzthiazuron 1.3 kg/ha; all as post-emergence) resulted in higher uptake of N, P and K by wheat. The uptake of nitrogen from crop under ‘no weeding’ (Control) was 32.6 and 52.9 kg/ha during 1980.81 and 1981–82, respectively. Isoproturon and metoxuron were more efficient in eliminating weed competition.