EFFECT OF WEED CONTROL TREATMENTS ON WEEDS AND YIELD OF WHEAT CV. GW - 496
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Date
2005
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AAU, Anand
Abstract
The field experiment was conducted during rabi season of 2003-04 at Agronomy Farm, B.A. college of agriculture, Anand Agricultural University, Anand to study the "Effect of weed control treatments on weeds and yield of wheat cv. GW - 496". The soil of the experimental field was loamy sand in texture, low in available nitrogen, medium in available phosphorus and high in potassium with slightly alkaline in reaction. Fourteen treatments comprising isoproturon at 0.50, 0.75 and 1.0 kg a.i. ha-1 each applied as pre-, early-post and post-emergence, pendimethalin at 0.75 kg ha-1 applied as pre-emergence, 2,4-D (ester form) at 0.75 kg ha-1 applied as post-emergence, manual weeding once (20 DAS)and twice (20 and 40 DAS) and weedy check were arranged in Randomized Block Design with four replications. All the herbicides were sprayed as per treatments using knapsack sprayer fitted with flat fan nozzle in a spray volume of 5001 water ha-1. Wheat variety GW-496 at seed rate of 125 kg ha-1 was sown at a spacing of 22.5 cm on November 17, 2003 and harvested on March 13, 2004. The crop was fertilized vwth 120: 60: 40 kg N, P2O5 and K2O ha-1 through diammonium phosphate, urea and muriate of potash, respectively, as per the recommendations. Growth characters like periodical plant height when recorded at 60, 90 DAS and at harvest remained unaffected by weed control treatments. However, the plant height recorded at 30 DAS significantly influenced due to weed control treatments. Significantly the lowest plant height was recorded at 30 DAS with pre-emergence application of isoproturon @ 1.0 kg ha-1 due to its phytotoxic effect on wheat crop. Two hand weedings (at 20 and 40 DAS-WB) and the post-emergence application of isoproturon @ 1.0 kg ha-1 (W9) being at par but they recorded significantly the highest values of yield attributes viz., effective tillers plant-1, ear length, number of spikelets ear-1, number of grains ear-1 and test weight when compared with the rest of the weed control treatments. However, the influence of weed control treatments on number of total tillers plant-1 and initial plant stand m-1 row length was found non-significant. Significantly higher grain yield of wheat was recorded under two hand weedings (at 20 and 40 DAS), followed by isoproturon @ 1.0 kg ha-1 as post-emergence. However, straw yield of wheat did not differ significantly due to weed control treatments. Harvest index was recorded significantly higher with two hand weedings (at 20 and 40 DAS), though it was remain at par with W9 and We during the course of investigation. Weed population and dry weight of weeds m-2 at 20 DAS was recorded significantly the highest with W2, W3, W5, W6, W8, W9, W11 and W14 as compared to the rest of the treatments in which herbicides were applied as pre-emergence for controlling weeds. Significantly the highest and the lowest dry weight of weeds at harvest was recorded under unweeded control as well as by W13 and W9, respectively. Latter both the treatments were on par with each other. Weed control efficiency was recorded significantly higher under two hand weedings (at 20 and 40 DAS), but it was at par with isoproturon @ 1.0 kg ha-1 as postemergence. Two hand weedings (at 20 and 40 DAS) recorded the highest net returns of Rs.32634 ha-1, followed by isoproturon @ 1.0 kg ha-1 as post-emergence with net returns of Rs.31792. Both these treatments secured the highest but equal values of CBR 1: 3.23. The lowest CBR of 1:2.29 was obtained under weedy check. Based on the results of field experiment, it can be concluded that for potential production and higher net returns from wheat cv. GW-496 in loamy sand soil of Middle Gujarat, the crop should be kept weed free either by two hand weedings or with isoproturon @ 1.0 kg ha-1 as post-emergence application.
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AGRONOMY, AGRICULTURE, A STUDY