Effect of Weed Management and Phosphorus Levels on Weed Dynamics and Crop - Weed Competition for Nutrients in Indian Mustard (Brassica juncea L.)

Field investigations were carried out during the winter seasons of 1998–99 and 1999–2000 at Udaipur, to evaluate the effect of different weed management practices and phosphorus levels on density and dry matter of weeds and crop-weed competition for nutrients in Indian mustard [Brassicajuncea (L.) Czem & Coss.). Pre-emergence application of oxyfluorfen @ 0.125 kg ha⁻¹ significantly reduced the density and dry matter of weeds in comparison to other practices and resulted in highest seed yield of mustard. Minimum uptake of NPK and S by weeds was also observed under oxyfluorfen treated plots. On contrary, highest uptake by crop plants was registered under oxyfluorfen treatment closely followed by pendimethalin. Phosphorus levels had no significant effect on weed density but weed dry matter at 60 days after sowing increased significantly upto 60 kg P₂O₅ ha⁻¹. During both the years mustard yield increased significantly upto 40 kg P₂O⁵ ha⁻¹.