Chemical weed control in wheat (Triticum aestivum) and its residual effects on greengram (Vigna radiata)

A field experiment was conducted from winter (rabi) 2013–14 to rainy season (kharif) 2015 on sandy-loam soil, to assess the comparative efficacy of different chemical herbicides and their combinations for effective weed control in wheat (Triticum aestivum L.) and their residual effect on succeeding greengram [Vigna radiate (L.) R. Wilczek] crop at Instructional Farm, Sumerpur, Rajasthan. The experiment comprised 9 treatments and the herbicides were applied at 30–35 days after sowing (DAS) as prescribed. The application of sulfosulfuron + metsulfuron methyl @ 32 g/ha recorded significantly lower weed dry matter and weed index along with highest weed-control index (76.73%). This herbicides combination also resulted in the highest grain yield of wheat (3.82 t/ha) along with highest net return and maximum benefit to cost ratio of the system in the tune of 3.4: 1 as compared to weedy check. The herbicides failed to influence a significant increase on seed yield of succeeding greengram during kharif seasons in both years. Uncontrolled weed growth throughout the crop growth period caused an average yield reduction of 57% in wheat crop (2.5 t/ha).