INTEGRATED WEED MANAGEMENT IN PEARLMILLET [Pennisetum glaucum (L.) R. Br. Emend. Stuntz]
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Date
2015
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Acharya N.G. Ranga Agricultural University, Guntur
Abstract
A field experiment was conducted at S. V. Agricultural College Farm, Tirupati campus of Acharya N.G. Ranga Agricultural University of Andhra Pradesh, during kharif, 2014, to study the effect of integrated weed management practices on growth and yield of pearlmillet. The present investigation was laidout in a randomized block design with three replications. The experiment consisted of ten weed management practices viz., preemergence application of atrazine @ 750 g a.i. ha-1 (T1), pre-emergence application of oxyflourfen 100 g a.i. ha-1 (T2), pre-emergence application of atrazine @ 750 g a.i. ha-1 fb hand weeding at 30 DAS (T3), pre-emergence application of oxyflourfen @ 100 g a.i. ha-1 fb hand weeding at 30 DAS (T4), pre-emergence application of atrazine fb post-emergence application of chlorimuron-ethyl 10% + metsulfuronmethyl 10% @ 8 g a.i. ha-1 (T5), pre-emergence application of atrazine fb postemergence application of ethoxysulfuron @ 37.5 g a.i. ha-1 (T6), pre-emergence application of oxyflourfen fb post-emergence application of chlorimuron-ethyl 10% + metsulfuron-methyl 10% @ 8 g a.i. ha-1 (T7), pre-emergence application of oxyflourfen fb post-emergence application of ethoxysulfuron @ 8 g a.i. ha-1 (T8), hand weeding twice at 20 and 40 DAS (T9) and weedy check (T10). The test hybrid used in the present study was PHB –306. Weed flora observed in the experimental field accounted for three species of grasses, two species of sedges and ten species of broad leaved weeds. The lowest weed density and dry weight of weeds with the highest weed control efficiency was observed with hand weeding twice at 20 and 40 DAS (T9), which was however on par with pre-emergence application of atrazine @ 750 g a.i. ha-1 fb one hand weeding at 30 DAS (T3). Pre-emergence application of atrazine @ 750 g a.i. ha-1 fb
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post-emergence application of ethoxysulfuron @ 37.5 g a.i. ha-1 (T6) or chlorimuron-ethyl 10% + metsulfuron-methyl 10% @ 8 g a.i. ha-1 (T5) and preemergence application of atrazine @ 750 g a.i. ha-1 alone (T1) were the next best treatments for the above said weed parameters, which maintained statistical similarity with each other. Pre-emergence application of oxyflourfen @ 100 g a.i. ha-1 alone (T2) or pre-emergence application of oxyflourfen @ 100 g a.i. ha-1 fb hand weeding at 30 DAS (T4) or post-emergence application of herbicides were inferior over that of atrazine. The highest weed density and dry weight of weeds along with the lowest weed control efficiency was associated with unweeded check (T10). The lowest nutrient uptake by weeds was observed with hand weeding twice at 20 and 40 DAS (T9), which was comparable with pre-emergence application of atrazine fb one hand weeding at 30 DAS (T3). The nutrient drain in the unweeded check (T10) recorded the highest nutrient uptake by weeds i.e., 23.4, 4.3 and 23.1 kg N, P and K ha-1, respectively. Among the weed management practices studied, hand weeding twice at 20 and 40 DAS (T9) resulted in the highest values of growth parameters viz., plant height, LAI, total number of tillers plant-1 and dry matter production and the highest values of yield attributes viz., number of panicles plant-1, panicle length, panicle girth, panicle weight, number of grains panicle-1 and test weight. These parameters were on par with pre-emergence application of atrazine fb one hand weeding at 30 DAS (T3). Pre-emergence application of oxyflourfen (T2, T4, T7 and T8) showed phytotoxicity scoring of ‘4.0’ on pearlmillet. The highest grain and straw yield was recorded with hand weeding twice at 20 and 40 DAS (T9), which was however comparable with pre-emergence application of atrazine fb one hand weeding at 30 DAS (T3). These treatments recorded 86.5 and 83.8 per cent higher yield, respectively compared to unweeded check (T10). The highest nutrient uptake by crop and the lowest nutrient uptake by weeds were noticed with hand weeding twice at 20 and 40 DAS (T9), which was comparable with pre-emergence application of atrazine fb one hand weeding at 30 DAS (T3). Among the weed management practices tried, the highest gross returns were observed with hand weeding twice at 20 and 40 DAS (T9), which was on par with pre-emergence application of atrazine fb one hand weeding at 30 DAS (T3). However, the later weed management practice recorded significantly higher net returns and benefit-cost ratio. In conclusion, the present study has revealed that hand weeding twice at 20 and 40 DAS resulted in effective control of all the categories of weeds and resulted in higher grain yield and gross returns. Pre-emergence application of atrazine @ 750 g a.i. ha-1 supplemented with hand weeding at 30 DAS recorded the highest net returns and benefit-cost ratio in pearlmillet.
Description
INTEGRATED WEED MANAGEMENT IN PEARLMILLET [Pennisetum glaucum (L.) R. Br. Emend. Stuntz]
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