author(s)
Manisha Uraon

abstract
The present investigation entitled “Studies on efficacy of pre- mix penoxsulam + pendimethalin on weed growth, yield and economics of direct seededrice” was carried out at Instructional cum Research Farm, Indira Gandhi Krishi Vishwavidyalaya, Raipur during kharif season of 2015. The soil of experimental field was sandy loam in texture (Inceptisols), neutral in pH and has 0.44% organic carbon, low nitrogen, medium phosphorus and high potassium content. Experiment was laid out in Randomized Block Design (RBD) with three replications. The treatments consisted of fourteen different weed management treatments viz, T₁ Penoxsulam + Pendimethalin (10+240 g/l) SE @ 20 + 480 g a.i. ha⁻¹, Tâ‚‚ Penoxsulam + Pendimethalin (10+240 g/l) SE @ 22.5 + 540 g a.i. ha⁻¹, T₃ Penoxsulam + Pendimethalin (10+240 g/l) SE @ 25 + 600 g a.i. ha⁻¹, Tâ‚„ Penoxsulam + Pendimethalin (10+240 g/l) SE @ 50 + 1200 g a.i. ha⁻¹, Tâ‚… Penoxsulam + Pendimethalin (10+240 g/l) SE @ 100 + 2400 g a.i. ha⁻¹, T₆ Penoxsulam 24% SC 20 g a.i. ha⁻¹, T₇ Penoxsulam 24% SC @ 22.5 g a.i. ha⁻¹, T₈ Penoxsulam 24% SC @ 25 g a.i. ha⁻¹, T₉ Pendimethalin 30% EC @ 540 g a.i. ha⁻¹, T₁₀ Pendimethalin 30% EC @ 600 g a.i. ha⁻¹, T₁₁ Pendimethalin 30% EC @ 1000 g a.i. ha⁻¹, T₁₂ Pendimethalin 30% EC @ 1500 g a.i. ha⁻¹, T₁₃ hand weeding at 20 and 35 DAS and T₁₄ untreated check. The result yield attributing characters like effective tillers m⁻², number of total and filled grains panicle⁻¹, panicle weight, panicle length, grain and straw yield. It was followed by treatments Penoxsulam + Pendimethalin (10+240 g/l) SE @ 50 + 1200 g a.i. ha⁻¹ (Tâ‚„) and hand weeding at 20 and 35 DAS (T₁₃). Weed density, weed dry weight and weed control efficiency were significantly influenced by different weed control treatments. Treatment Penoxsulam + Pendimethalin (10+240 g/l) SE @ 100 + 2400 g a.i. ha⁻¹ (Tâ‚…) showed good performance with minimum weed dry weight, highest weed control efficiency and lowest weed index followed by Penoxsulam + Pendimethalin (10+240 g/l) SE @ 50 + 1200 g a.i. ha⁻¹ (Tâ‚„) and hand weeding at 20 and 35 DAS (T₁₃). The number of spikelets panicle⁻¹, filled grains panicle⁻¹, panicle length and panicle weight were found to be reduced in untreated check (T₁₄) as a result of weed competition.