Crop-establishment methods and weed management effects on weeds, wheat (Triticum aestivum) yield and economics under a conservation agriculture-based rice (Oryza sativa)–wheat system
Keywords:Clodinafop-propargyl, Crop residue, Gross returns, Metsulfuron-methyl, Phalaris minor, Weed interference, Zero-tillage
A field experiment was conducted at the ICAR-Indian Agricultural Research Institute during the winter (rabi) season of 2018–19 and 2019–20 involving 6 tillage and residue practices, viz. T1 , zero-till (ZT) direct-seeded rice (Oryza sativa L.) (ZTDSR)–zero-till wheat [Triticum aestivum (L.) emend Fiori & Paol] (ZTW); T2 , ZTDSR + wheat residue (WR)–ZTW + rice residue (RR); T3 , ZTDSR + WR + brown manuring (BM) – ZTW+RR; T4 , ZTDSR–ZTW– ZT mungbean [Vigna radiata (L.) R. Wilczek] (ZTMB); T5, ZTDSR + mungbean residue (MBR) – ZTW + RR – ZTMB+WR; T6 , puddled transplanted rice (PTR)–conventional till wheat (CTW) in main plot; and 4 weed-control treatments, i.e. W1 , un-weeded control; W2 , Total (ready mix of sulfosulfuron + metsulfuron-methyl) 0.040 kg/ha at 30 day after sowing (DAS); W3 , tank-mixture of clodinafop-propargyl 0.060 kg/ha + metsulfuron-methyl 0.004 kg/ha at 30 DAS; W4 , tank-mixture of clodinafop-propargyl 0.060 kg/ha + carfentrazone-ethyl 0.02 kg/ha at 30 DAS in sub-plot under a split-plot design and replicated thrice. Treatment T6 resulted in significantly higher population and dry weight of littleseed canarygrass (Phalaris minor Retz.), yellow sweet clover [Melilotus indica (L.) All.] and swine cress [Coronopus didymus (L.) Smith] than other treatments, whereas, population and dry weight of common lambsquarter (Chenopodium album L.), sour dock (Rumex dentatus L.) and annual sowthistle (Sonchus oleraceus L.) were significantly higher under T1 and T4 treatments. The treatment T5 registered ~62, 44, 35, 31 and 24% lower population of P. minor than T6 , T1 , T4 , T2 and T3 treatments, respectively. Similarly, total weed population and total weed dry weight were ~38 and 33% lower under T5 compared with T6 treatment respectively. Better wheat growth and lower weed interference under T5 treatment led to 14.6% higher wheat grain yield under this treatment than T6 . The tank- mix of clodinafop-propargyl + metsulfuron significantly reduced the population and dry weight of all weeds compared to UWC and it led to 88.9% weed-control efficiency (WCE) and 89.4% weed-control index (WCI) in wheat. Therefore, growing of wheat under zero-till triple cropping system with rice, wheat and mungbean residues (T5 ) combined with tank-mix application of clodinafop + metsulfuron at 30 DAS may be recommended for better weed management, and higher productivity and profitability from wheat in Indo-Gangetic Plains (IGP) of India and in similar agro-ecologies of the tropics/ sub-tropics.