Effect of fertility levels and herbicides on growth, yield and nutrient uptake of direct-seeded rice (Oryza sativa)

A field experiment was conducted during the rainy seasons of 1999 and 2000, to find out the effect of fertility levels and herbicides on growth, yield and nutrient uptake of direct-seeded rice (Oryza sativa L). The fertility level up to N₄₅P₄₀K₃₀, + 25 kg ZnSO₄ + foliar spray of micronutrient mixture (thrice) proved the best, producing 6.34 q/ha extra grain and Rs 6,968/ha extra net return over no fertility level. Hand-weeding (20 and 40 days after sowing) showed 72% weed-control efficiency with additional grain yield up to 9.91 q/ha and net return up to Rs 5,042/ha over unweeded control. Pendimethalin 1.0 kg/ha or anilophos 0.40 kg/ha each with 2,4-D (Na-salt) 0.60 kg/ha showed 50 to 51% weed-control efficiency and proved the best substitute of hand-weeding (twice), the extra net return being Rs 3,689 and Rs 3,074/ha, respectively, over unweeded control. The seed protein and nutrient uptake were also increased significantly with increasing fertility levels and the herbicides over their respective controls.