Efficacy of different weed control treatments in blackgram [vigna mungo]
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Date
2015
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JNKVV
Abstract
ABSTRACT
The present study entitled “Efficacy of different weed control treatments in Blackgram (Vigna mungo L.).” was conducted at Research farm, College of Agriculture, Tikamgarh during Kharif, 2014-
15. The experiment was aimed to find out the efficacy of herbicides on weeds and crop growth and to determine the economic viability of herbicidal weed control in blackgram. The soil of the experimental
area was clayey loam, which was medium in organic carbon, low in available nitrogen and phosphorus but medium in potassium content having neutral pH and normal electrical conductivity.
The experiment was laid out in “Randomized block design” with ten treatments, replicated thrice. The treatments comprised of pre emergence herbicides viz; pendimethalin @ 0.75 kg a.i. ha-1, pendimethalin @ 0.75 kg a.i. ha-1 followed by hand weeding at 30 DAS, pendimethalin @ 0.75 kg a.i. ha-1 followed by hand hoeing at 30 DAS, Alachlor @ 1.0 kg a.i. ha-1, Alachlor @ 1.0 kg a.i. ha-1 followed by hand weeding at 30 DAS, Alachlor @ 1.0 kg a.i. ha-1 followed by hand hoeing at 30 DAS, post-emergence herbicides viz; Quizalofop-p-ethyl @ 50 g a.i. ha-1 at 150 DAS and these treatments were compared with two hand weeding at 20 and 40 DAS and weedy check. The blackgram variety “AZAD-1” was sown on July 14, 2014 with seed rate of 20 kg ha-1 in rows 30 cm apart with fertilizer dose of 20:40:20 kg ha-1. Pre-emergence herbicides were applied on next day of sowing. The herbicides were applied in 500 liters of water ha-1 by knapsack sprayer, using flat fan nozzle.
The major weed species observed in the experimental area were Echinochloa colonum, Cyperus rotundus and Commelina benghalensis among the monocot and Phyllanthus niruri, Digera arvensis, Trienthema monogyna, Corchorus olitorious and Leucas aspera among Dicots. The relative density of monocots was 28.03 % while dicots were to the tune of 71.92 % of the total weed population at harvest stage.
All the herbicidal treatments and hand weeding except quizalofop-p-ethyl reduced the weed intensity as compared to weedy check. Hand weeding twice was most effective and recorded minimum weed density among all the treatments. Application of pendimethalin @ 0.75 kg a.i. ha-1 followed by hand weeding and hand hoeing at 30 DAS, alachlor @ 1.0 kg a.i. ha-1 followed by hand weeding and hand hoeing at 30 DAS recorded the lower weed intensity than their alone application. Whereas, the herbicidal treatments and hand weeding significantly reduced the weed biomass compared to weedy check. Among the herbicides, pre-emergence application of pendimethalin @
0.75 kg a.i. ha-1 followed by hand weeding and alachlor @ 1.0 kg a.i. ha-1 followed by hand weeding at
30 DAS significantly reduced the weed biomass and registered higher weed control efficiency than their alone application, one hand hoeing and post-emergence application of quizalofop-p-ethyl. Hand weeding superseded over all the treatments and attained minimum weed biomass (4.80 g m-2) with weed control efficiency of 99.14 % followed by pendimethalin @ 0.75 kg a.i. ha-1 fb by hand weeding at 30 DAS (94.97 %).
All the crop growth parameters, like leaf area index, number of branches per plant were significantly higher under two hand weeding followed by pendimethalin @ 0.75 kg a.i. ha-1 fb by hand weeding at 30 DAS (94.97 %). than their alone application, quizalofop-p-ethyl @ 50 g a.i. ha-1 at 15
DAS, one hand hoeing at 30 DAS and weedy check. Yield attributing characters viz; number of pods plant-1, number of seeds pods-1 and test weight attained significantly higher values under herbicidal treatments and hand weeding than weedy check.
Seed yield, straw yield and harvest index was significantly higher under all the weed control practices over weedy check. Two hand weeding at 20 & 40 DAS recorded the highest seed yield (1447.78 kg ha-1) among all the treatments followed by pendimethalin @
0.75 kg a.i. ha-1 followed by hand weeding at 30 DAS (1416.67 kg ha-1). Among the alone herbicide applications, pre-emergence application of pendimethalin @ 0.75 kg a.i.ha-1 and alachlor 1.0 kg a.i.ha-
1 (1311.11 and 1305.56 kg ha-1) produced significantly higher seed yield over post-emergence
application of quizalofop-p-ethyl @ 50 g a.i. ha-1 at 15 DAS.
The highest gross and net monetary return obtained with two hand weedings whereas the B:C ratio was the highest with the application of pendimethalin @ 0.75 kg a.i. ha-1 followed by alachlor @ 1.0 kg a.i. ha-1.
Description
Keywords
weeds, control methods, herbicides, cultivation, harvesting, yields, drying, sowing, planting, crops