Nitrogen and weed management effects on weeds and yield of barley in Kandahar, Afghanistan

Abstract

Growth and yield of barley (Hordeum vulgare L.) are highly influenced by nutrients and weed management. Nitrogen (N) is the most crucial nutrient to which barley crop responds readily. Efficient management of N and weeds can provide higher yield, better quality, and higher income to the farmers. Therefore, a field experiment was conducted in a split-plot design with three replications during winter season of 2019-20 in the Afghanistan National Agricultural Sciences and Technology University (ANASTU), Kandahar, Afghanistan to evaluate the effect of weed and N management on weeds growth and barley productivity. There were three weed management options in main plots, such as weedy check, herbicide use alone [post-emergence application (PoE) of clodinafop-propargyl 60 g/ha + metsulfuron-methyl 4 g/ha (tank-mix) at 30 days after sowing (DAS)], and integrated weed management (IWM) involving stale seed bed 15 days before sowing + wheat crop residue (2.5 t/ha) retention + clodinafop-propargyl + metsulfuron-methyl (tank-mix) PoE with half of the recommended dose at 30 DAS]. Four N levels (~0, 40, 80 and 120 kg N/ha, i.e., N0, N40, N80 and N120) were included as sub-plot treatments. The IWM led to significantly lower density and biomass of weeds at 40 and 70 DAS and significantly increased weed control efficiency (WCE) and weed control index (WCI). Clodinafop-propargyl (60 g/ ha) + metsulfuron-methyl (4 g/ha) (tank-mix) PoE also resulted in significantly lower density and biomass of weeds and higher WCE and WCI than weedy check at all stages. IWM being at par with clodinafop-propargyl + metsulfuron-methyl (tank-mix) PoE led to higher growth (crop height, dry weight, leaf area index and growth rate) and yield of barley. On the contrary, the effect of nitrogen levels was not significant on the weed density and biomass reduction. N120 and N80 were comparable with respect to growth, yield attributes and yield of barley. Thus, IWM with 80 kg N/ha may be recommended for better weed management and higher barley yield and income in Kandahar, Afghanistan.