Ecology, Environment and Conservation Paper

EFFECT OF INTEGRATED AND PURELY CHEMICAL WEED MANAGEMENT PRACTICES ON YIELD ATTRIBUTING CHARACTERS, YIELD, WEED DENSITY, WEED DRY WEIGHT AND TOTAL MICROBIAL POPULATION IN SOIL OF PIGEON PEA (CAJANUS CAJAN (L.) MILL SP.)

S. K. DAS, B. Biswas, G. Moinuddin3 and A. Hansda

Abstract

Field experiments were conducted for two years at Pulses and Oilseeds Research Station, Berhampore, Murshidabad, West Bengal, India during kharif 2010 and 2011 to develop an efficient integrated weed management practice with newer herbicidal molecules in pigeonpea. The experiment was laid out in a randomized block design with three replications having nine treatments. Experimental results revealed that highest seed yield (2124.3 kg ha-1) was recorded under the treatment twice hand weeding at 25 and 50 DAS and lowest with weedy check (1026 kg ha-1). Application of chemical herbicides along with or without one hand weeding significantly improved the seed yield over weedy check. Among the integrated weed control measures application of Pendimethalin 30 EC @ 0.75 kg a.i./ha as PE (Pre-emergence) at 1 DAS + One hand weeding at 50 DAS recorded highest seed yield of pigeonpea (2010.7 kg ha-1) which was found at par with application of Imazethapyr @ 0.75g a.i./ha as PoE (15-20 DAS) + Paraquat @0.40 kg a.i./ha at 8 WAS (1987 kg ha-1). Highest weed control efficiency (84.1%) was recorded under hand weeding twice followed by application of Pendimethalin 30 EC @ 0.75 kg a.i./ha as PE (Pre-emergence) at 1 DAS + One hand weeding at 50 DAS (80.7% WCE). Among the purely chemical weed management practices application of Imazethapyr @ 0.75g a.i./ha as PoE (15-20 DAS) + Paraquat @0.40 kg a.i./ha at 8 WAS recorded the lowest weed density (72.2 nos.m-2) and weed dry weight (15.9 gm-2) and highest WCE (77.8%). Chemical weed control measures increased the total microbial population by 41.3 to 88.3% over weedy check and 23.7 to 64.8% over twice hand weeding.