Effect of planting pattern and weed management on nutrient uptake and economics of rabi sunflower and its associated weeds.

The uptake of nutrients by sunflower crop and its associated weeds was studied under two planting patterns (45 x 30 cm and 60 x 22.5 cm) and six weed management practices (fluchloralin 1.0 kg/ha, pendimethalin 1.0 kg/ha, fluchloralin 0.5 kg/ha+pendimethalin 0.5 kg/ha, fluchloralin 0.5 kg/ha+pendimethalin 0.5 kg/ha supplemented with one HW at 40 DAS and HW twice at 20 and 40 DAS including unweeded check). Planting pattern of 45 x 30 cm significantly reduced the nutrient removal by weeds and consequently nutrient uptake by crop was increased. Among the weed management practices tried, the nutrient uptake by weeds was significantly lower with HW twice and it was at par with fluchloralin 0.5 kg/ha+pendimethalin 0.5 kg/ha supplemented with HW at 40 DAS. On an average, weeds under unweeded check removed 42.0 kg N, 15.5 kg P and 45.4 kg K/ha and monetary loss in terms of nutrient removal by weeds was maximum in unweeded check with an amount of Rs.1133/ha, besides reducing the seed yield by 62% than the best weed management practice, HW twice.