Crop-Weed competition and their management in blackgram

A field experiment was conducted for two summer reasons to identify critical period in irrigated summer sown blackgram (Vigna mungo L.) at Kanpur. Unchecked weed competition throughout the crop growth period caused a reduction of 40.10% in seed yield. Initial weed condition for the first 10 days after sowing did not cause significant loss in yield. Weed-free conditions maintained 40 days after sowing could not bring significant increase in seed yield. The critical period of crop-weed competition thus lies between 1040 days after sowing in irrigated summer sown blackgram. Application of herbicides viz., pendimethalin (1.00 kg/ha) as pre-emergence followed by fluazifop-p-butyl (0.375 kg/ha) as post-emergence demonstrated cent per cent mortality of Trianthema onogyna, a major dominating broad-leaved weed and Sorghum halepense perennial grass, respectively and recorded seed yield (1012 kg/ha) similar to that obtained under weed-free check (1016 kg/ha).