Weed-management and wheat productivity in a conservation agriculture-based maize (Zea mays)wheat (Triticum aestivum)mungbean (Vigna radiata) system in north-western Indo-Gangetic plains of India

Abstract

In this study, a possible weed management has been envisaged in zero-till (ZT) and conventional till (CT) wheat [Triticum aestivum (L.) emend. Fiori & Paol.] with and without residue during 201314 and 201415 using residue, N and weed-control treatments. It was observed that ZT with 5 t/ha maize (Zea mays L.) residue retention (ZT + R) + 75% N + rest N-based on GreenSeeker (GS) caused a considerable reduction in the population of nar- row-leaf, broad-leaf and total weeds compared to CT and ZT without residue. Pendimethalin (PMT) followed by sulfosulfuron (SSF) application significantly reduced the weeds population and dry weight than the unweeded con- trol (UWC). Wheat yield attributes were higher in ZT with residue retention (ZT + R) than conventional-tilled treat- ments. Application of PMT @ 1 kg/ha followed by SSF 25 g/ha combined with ZT with 5 t/ha maize residue reten- tion (ZT + R) + 75% N + rest N based on GreenSeeker (GS) resulting in higher wheat yield which was comparable with that in weed-free check (WFC). Zero tillage with or without residue reduced the nutrient uptake by weeds than the conventional tillage which led to the higher uptake of nutrients by crop in zero tillage condition over the years. The sum total amount of N, P and K removed by the crop was higher in ZT + R + 75% N + rest N based on GreenSeeker (GS) than CT-R + 100% N (farmer practice) to the tune of 23.8% and 34.6% in 201314 and 2014 15, respectively. The sequential application PMT and SSF had an edge over the ready-mix application of SSF+ metsulfuron methyl (MSM) in respect of nutrients uptake by crop which was due to the reduction in nutrients up- take by weeds by the former than the later. The treatment combination ZT + R + 75% N + rest N based on GreenSeeker (GS) and sequential application of PMT-SSF secured highest output energy than the CTR + 100% N with UWC and ready-mix application of SSF + MSM. The interaction between tillage, residue and N manage- ment with weed control practices for net benefit: cost ratio revealed that irrespective of residue the zero tillage fetched the higher net benefit: cost than conventional tillage. The partial cost-benefit of sequential as well as ready-mix application of herbicide was on a par under both the tillage condition. Therefore, ZT + R + 75% N + rest N based on GreenSeeker (GS) and sequential application of PMT-SSF can be recommended for wheat produc- tion in north-western Indo-Gangetic plains of India.