Evaluation of efficacy of different herbicides on weed dynamics and performance of dwarf fieldpea in Tarai soils of Uttarakhand, India

A field experiment was conducted during rabi season of 2010-2011 and 2011-12 at Pantnagar in tarai soil of Uttarakhand to study the effect of different herbicides on plant growth, weed dynamics, nutrient uptake and yield of dwarf fieldpea. Results revealed that uncontrolled weeds caused 27.3 and 39.4 per cent reduction in grain yield of dwarf fieldpea during first and second year, respectively as compared to two hand weedings done at 20 and 40 days after sowing (DAS). Among the chemical treatments, minimum nutrient removal of 3.0 kg N,0.5 kg P and 3.3 kg K ha-1by weeds was recorded under pendimethalin 1.0kg ha-1 (PE)+ imazethapyr 0.05 kg ha-1 (POE,30 DAS) as against 11.4 kg N, 1.96 kg P and 12.6 kg K ha-1, respectively in weedy check Two hand weedings done at 20 and 40 DAS, which remained at par with pendimethalin1.0 kg ha-1 (PE) + imazethapyr 0.05 kg ha-1 (POE, 30 DAS) and pendimethalin 1.0kg ha-1(PE) + quizalofop ethyl 0.05kg ha-1(POE, 30 DAS) caused significant reduction in weed dry weight and increased the value of plant height, number of leaves per plant and dry matter accumulation per plant as compared to weedy check. These treatments produced 27.1, 23.1 and 16.0 per cent more number of pods/plant and yielded 50, 40 and 35.7 per cent higher grain yield, respectively over weedy check. The maximum weed control efficiency was computed under two hand  weedings followed by pendimethalin 1.0 kg  ha-1 (PE)+ imazethapyr 0.05kg ha-1 (POE, 30 DAS) and pendimethalin 1.0kg  ha-1  (PE)+ quizalofop ethyl  0.05 kg  ha-1 (POE, 30 DAS).