Effect of weed management practices on nutrient uptake by summer mungbean (vigna radiata (l.) wilczek) and associated weeds

Field studies carried out at the Punjab Agricultural University, Ludhiana during 1986 and 1987 indicated that under unweeded conditions, summer mungbean could utilize only 55.6, 10.2 and 49.1 kg'ha of nitrogen, phosphorus and potassium, respectively, whereas weeds removed 79.1, 19.8 and 79.1 kg/ha. Effective weed management through fluchloralin 0.75 kg/ha resulted in an uptake of 111.4, 22.7 and 97.5 kg/ha N,P and K, respectively by the crop and allowed only 3.1, 0.7 and 4.1 kg/ha, NPK to be dtpleted by weeds. Pre-emergence application of pendimethalin at at 0.75 kg/ha and two hand Aveedings (3 and 5 weeks after sowing) also proved equally effective in increasing uptake of nutrients by the crop. Closer-row-spacing at 15 cm instead of 25 cm could not reduce the nutrient depletion by weeds.