Weed and Nitrogen Management Effects on Weed Infestation and Crop Productivity of Wheat–Mungbean Sequence in Conventional and Conservation Tillage Practices

Weeds appear as a challenge in conservation agriculture, and hence, weed management is of paramount importance. The nitrogen (N) management under changing tillage scenarios is another important dimension of research. Therefore, a field experiment was laid out in a split-plot design with six tillage, residue and N management options in main plots and four weed control practices in subplots. The results showed that the zero tillage (ZT) + residue (R) + 75% of required N + rest N based on GreenSeeker™ (GS) and sequential application of pendimethalin followed by sulphosulphuron alone and in combination resulted in significant reductions in weed dry weight and caused a considerable increase in weed control efficiency and weed control index in wheat. Their carry-over effect was also significant on the reduction in weed growth in mungbean. Residue retention in ZT gave 5.5 and 6.1% higher wheat grain yield in 2013–2014 and 2014–2015, respectively, than the residue incorporation, whereas in mungbean the increment was to the extent of 8.4 and 7.8%. Zero tilled plots recorded 25.5 and 42.8% higher water productivity (for wheat) and mungbean productivity. Highest net energy returns were observed in ZT + R + 75N + GS in wheat in both the years. The treatment ZT + R + 75N + GS also fetched higher gross and net returns in wheat and mungbean. In all cases, herbicides with sequential application proved better than one-time ready-mix application. © 2017, NAAS (National Academy of Agricultural Sciences).