Weed dynamics and grain yield of maize (Zea mays L.) as influenced by different fertility levels and weed control measures under temperate Kashmir

A field experiment was conducted during kharif seasons of 2004 and 2005 at the experimental farm of the Division of Agronomy, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir to study weed dynamics and grain yield of maize (Zea mays L.) as influenced by different fertility levels and weed control measures. Experimental field was dominated with Echinochloa spp., Cynodon dactylon, Portulaca oleracea and Cyperus spp. Highest total weed density, dry matter accumulation and nitrogen uptake (kg ha⁻¹) were recorded with the treatment of N₉₀ (F₁) than N₉₀ + Azotobacter (F₂), N₁₂₀ (F₃) and N₁₂₀ + Azotobacter (F₄) treatments. Significantly longest cobs, cob diameter, number of rows per cob and highest weed control efficiency (WCE) were recorded with the higher fertility level of N₁₂₀ + Azotobacter (F₄) as compared to N₉₀ (F₁) treatment during both the experiments. Minimum total weed density, dry matter accumulation and nitrogen uptake (kg ha⁻¹) were observed under polyethylene mulch (W5). On the contrary, highest grain yield (51.42 q ha⁻¹) and WCE (67.3 and 66.54%) were recorded in polyethylene mulch (W5) than rest of the weed control measures. Benefit cost ratio was highest with N₁₂₀ + Azotobacter (F₄) and atrazine @ 1.0 kg ha⁻¹ (W₃) treatments respectively. Uncontrolled weed growth caused 73.41 per cent reduction in grain yield of maize.