Economically viable weed management practices in black gram

Introduction

In India, black gram is a significant pulse crop, which is cultivated in both the summer and the kharif season. In this crop cultivation, a large number of weeds have been identified and growing as a result of frequent irrigations in the summer and monsoon rains in the kharif season. Unchecked weeds have been shown to significantly reduce black gram grain yields; losses for summer black gram can range from 46.0 to 53.0% (Vaishya et al., 2003; Bhandari et al., 2004) [9,1] , while losses for kharif black gram can range from 43.2 to 64.1%. For summer black gram, the essential period for crop-weed competition is 10-40 days after sowing (Kumar and Tewari, 2004b) [2,3] , and in certain cases, it may even be 25-35 days after sowing (Randhawa et al., 2002) [7] . Consequently, to get high yields of black gram, weeds must be removed at the proper time and with the appropriate technique. The conventional approaches to weed management, such as manual weeding or intercropping, are labour-intensive, costly, and ineffective. Furthermore, because of rising costs and a labour shortage, thorough weeding is not feasible at crucial periods of crop growth. Furthermore, the cultural methods of controlling weeds are hampered by persistent rains throughout the early phases of crop growth. It is impossible to eradicate weeds completely with a single herbicide application. In these situations, using pre-and post-emergence herbicides consecutively or in combination will successfully control the weeds. There are currently more different herbicides and their mixes with varied prices are available in the market that efficiently control a wide range of weeds. Keeping these things in consideration, the present research investigation was conducted to determine how weed can be controlled and the yield of irrigated black gram were affected by pre-and post-emergence herbicides as well as manual weeding techniques with prior economically benefited chemical combination is determined.

Materials and Methods

A field experiments were carried out at college farm, Agricultural College, Jagtial, India using the recently released black gram variety MBG-1070, during the Rabi season of 2023-2024 to determine the effects of pre-and post-emergence herbicides as well as hand weeding techniques on weed control and yield of irrigated black gram under irrigated conditions. The experiment was laid out in a randomized block design, comprising of eight treatments (T 1 to T 8 ) as pre-emergence application of Pendimethalin 30% EC 1000 g ha -1 PE at 1 DAS (T 1 ), Imazethapyr + Imazamox 35% + 35% WG (pre-mix) 80 g ha -1 PE at 1 DAS (T 2 ), Fomesafen + Fluzifop-p-butyl 11.1% + 11.1% SL (pre-mix) 220 g ha -1 PoE at 20 DAS (T 3 ), Aciflurfen-sodium + Clodinafopproparyl 16.5% + 8% EC (pre-mix) 245 g ha -1 PoE at 20 DAS (T 4 ), Propaquizafop + Imazethapyr 2.5% + 3.75 ME (pre-mix) 125 g ha -1 PoE at 20 DAS (T 5 ), Haloxyfop Rmethyl 108 g ha -1 10.5% EC PoE at 20 DAS (T 6 ), Hand weeding twice at 15 and 30 DAS (T 7 ), Unweeded check (T 8 ) were assessed using a randomized block design (RBD) with three replications. During the trial, the mean maximum and lowest temperatures were observed as 30.8 °C and 17.13 °C, respectively, 500 litres of water per hectare and a knapsack sprayer with a flat nozzle were used to apply the herbicides as pre-emergence(0-1DAS) and post-emergence (20 DAS). All additional recommended agronomic and plant protection practices were implemented to cultivate the crop, and intercultural operations were carried out as required. This includes all relevant information on crop production and yield characteristics. The experimental design data were statistically analysed using Fisher's analysis of variance approach, and treatment means were compared using an Ftest and the least significant difference test at a 5% probability level to determine critical difference (CD) values. On all of the gathered data, analysis of variance was carried out. Economic related data were also analysed carefully with considerations of all the required needs.

Results and Discussion

Seed yield (kg ha -1 ) Highest seed yield was obtained with T 7 treatment (795 kg ha -1 ) as the complete clearance of weeds at two intervals ie at 15 and 30 DAS paved to making better establishment of the crop and avoided crop weed competition at critical growth period, better translocation of nutrients and dry matter accumulation, similar results were found by Sahoo et al. (2017) [8] Among the herbicidal treatments, T 3 resulted in highest seed yield (725 kg ha -1 ), which is due to better control of weed growth by the chemical at 20 DAS, made the crop to flourish with maximum potential of growth and development, Similar results were reported in mung bean by (Yadav et al., 2022) [11] . Since the chemical treatment counteract the weed growth effect and the crop growth in positive manner result in better seed yield in comparison with all the treatment chemicals. Lowest seed yield was noticed with T 8 treatment (350 kg ha -1 ) which maybe due to high crop-weed competition for the nutrients and moisture throughout the crop period, Similar findings were reported by Mirjha et al. (2013) [5] .

Haulm yield (kg ha -1 ) Significantly higher haulm yield was noticed with T 7 treatment (1485 kg ha -1 ) followed by T 3 (1234 kg ha -1 ), which also acts as maximum haulm yield among all the herbicidal treatments, might be due to the Stover yield of black gram was significantly higher under these weed control treatments may be attributed mainly to the better control of weeds during different stages, manual removal of emerging weeds by hand by herbicides and thereby providing better yield attributes. Lowest haulm was observed with T 8 treatment (720 kg ha -1 ), which is due high crop weed competition and less dry matter accumulation. Similar findings were reported by (Vikas et al., 2013) [10] .

Since harvest index is statistically observed as nonsignificant, all the treatmental influence on the crop in uniform manner.

Economics

A. Cost of cultivation: (Rs ha -1 ) Highest cost of cultivation is observed with T 5 treatment (22,174/-) as might be due to expensive chemicals usage and T 4 (21,253/-), T 6 (21,074/-), T 7 (21,032/-) were found statistically on par with it as all the herbicide chemical combinations are more or less similar, whereas least cost of cultivation was noticed with T 8 (18,874/-) unweeded check as it is devoid of any type of chemicals and manual labours too.

B. Gross returns: (Rs ha -1 ) Highest gross returns was observed with T 7 (55,252/-), as which it is result of maximum seed yield from the crop followed by T 3 (50,387/-), which is also best among rest of the herbicidal treatments. Lowest gross returns was observed with T 8 treatment (21,920/-) due to receive of lesser seed yield.

Maximum net returns was observed with T 7 (34,220/-) as it implies with the difference of maximum gross returns and minimal cost of cultivation, followed by T 3 (30,413/-), in which it acts as best herbicidal treatment with maximum net returns in comparison with all the herbicidal treatments and unweeded check. Similar results were observed in the green gram crop which was reported by (Nanda et al., 2022) [6] . Lowest net returns was noticed with T 8 (3,046/-) unweeded check, because of lower seed yield.

D. Benefit -cost ratio (B:C ratio)

Highest B:C ratio was noticed with T7 treatment (2.6) as obtained and among the herbicidal treatments T3 treatment (2.5) was noticed and found that statistically at par with it, due to better gross returns over the cost of cultivation of the treatment, whereas lowest B:C ratio was observed with T8 treatment unweeded check (1.2) due minimal seed yield obtain over biological yield of the crop. Similar kinds of results were reported by (Mansoori et al., 2015) [4] .

Conclusion

Based on the data pertaining to the experimental treatments, T 7 treatment Hand weeding twice at 15 and 30 DAS observed to be better at net returns and B:C ratio followed by T3 treatment Fomesafen + Fluzifop-p-butyl 11.1% + 11.1% SL (pre-mix) 220 g ha -1 PoE at 20 DAS was observed to be performed as maximum net returns (30,413/) and highest harvest index (2.5) among all the herbicidal treatments, can be concluded as economically cost-effective chemical combination for the black gram cultivation.

Acknowledgement

AcknowledgementI am greatly pleased to express my sincere gratitude to the Professor Jayashankar Telangana State Agricultural university for funding of my research with the black gram crop.

References

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