Effect of weed management practices on weed dynamics and performance of black gram (Vigna mungo L.)

Introduction

Black gram [Vigna mungo L.] is one of the major grain legumes cultivated throughout the country. Because of its quick growth, short growth period, and ability to fix nitrogen, it works well in a variety of multiple and intercropping systems. It is extensively grown because of its excellent nutritional value, especially its high protein content and because it is used in traditional Indian cuisine. The main producing states are Telangana, Andhra Pradesh, Maharashtra, Madhya Pradesh, Tamil Nadu, and Uttar Pradesh. Tropical and subtropical areas are ideal for black gram growth. It is usually cultivated in the months of Rabi (winter) and Kharif (monsoon), and it needs a warm environment with moderate rainfall. Black gram might suffer a 42-51% yield loss due to weed competition (Balyan et al., 2016) [2] . Kumar et al., 2018 [7] , stated that weed management has become essential to maintain the production of this crop. Certain weed species or groups may be controlled with selective herbicides, while other weed species may not respond well to them. In this case, one set of weeds gets efficiently wiped off, while another group takes over and presents a serious threat to the crop. Chemical weed control is used by very few farmers when growing pulses like black gram. Pre-emergence herbicide pendimethalin is applied to suppress the first flush of weeds in most pulses, including black gram. This is insufficient on its own to manage the black gram's varied weed flora. Singh et al. (2014) [11] addressed about the necessity of post-emergence herbicide in order to lessen the demand for human labour and manage the second flush of weeds in pulses. In order to maintain the productivity of black gram, Kumar (2010) [6] emphasized the significance of discovering the broad-spectrum effective group of pre and post-emergence herbicides. In view of these considerations, an experiment was carried out to study the effectiveness of various weed management practices in black gram.

Materials and Methods

The field experiment was conducted at the College Farm, Agricultural College, Polasa, Jagtial (T.G), India, during rabi 2023-24 to investigate the effects of pre and post-emergence herbicide combinations on weed dynamics and performance of black gram.

Eight weed management treatments consist of T1 -Pendimethalin 30% EC 1000 g ha-1 Pre-emergence (PE) at 1 DAS, T2-Imazethapyr + Imazomox 35%+35% WG (pre-mix) 80 g ha-1 PE at 1 DAS, T3-Fomesafen + Fluzifop-p-butyl 11.1%+11.1% SL (pre-mix) 220 g ha-1 post-emergence (PoE) at 20 DAS, T4-Aciflurfen-sodium+Clodinafop-proparyl 16.5%+8% EC (premix) 245 g ha-1 PoE at 20 DAS, T5-Propaquizafop + Imazethapyr 2.5%+3.75 ME (pre-mix) 125 g ha-1 PoE at 20 DAS, T6-Haloxyfop R-methyl 10.5 % EC 108 g ha-1 PoE at 20 DAS, T7-Hand weeding twice at 15 and 30 DAS, T8-Unweeded check were assessed using a randomized block design with three replications. The well-drained sandy clay loam soil at the experimental location featured a texture of 65.86 % sand, 6.37% silt, and 27.70% clay and its chemical properties included a pH of 6.95, EC of 0.722 d. Sm-1 has a bulk density of 1.52 g.cm -3 and a medium level of organic carbon content of 0.52%. Before crop sowing, the soil's nutritional status was low in nitrogen (250 kg ha-1), high in phosphorus (35 kg ha-1), and high in potassium (296 kg ha-1). The mean maximum and lowest temperatures for the experimental period were 30.8°C and 17.13°C, respectively. The black gram variety MBG-1070, which harvests in 80-85 days, was seeded at a seed rate of 20-25 kg ha-1 with a spacing of 30 × 10 cm. At the time of sowing, the soil was applied as 20:50:0 kilogram per hectare fertilizer treatment in the form of urea (kg ha-1) and single super phosphate (kg ha-1).

Weed management treatments were applied as per the treatment schedule. Herbicides were applied using a knapsack sprayer with a flat fan nozzle and spray volume of 500 Litres of water per hectare. The crop was grown following package of practices of black gram. Weed density of grasses, sedges, and broad-leaved weeds were counted in randomly chosen locations in each plot using a 0.5 × 0.5 m quadrant (0.25 m 2 ) at every 15 days interval up to the crop physiological maturity stage. For statistical analysis, the data on the total number of weeds and the dry matter of weeds were recorded, gathered, and then transformed using the square root method (√x+0.5) to standardize their distribution (Gomez and Gomez 1984) [3] . The removed weeds from the quadrats were dried for 24 hours at 65 o C to record their constant weight, which was then reported in grams per square meter. The formula used to compute the weed control efficiency (WCE) was proposed by Patil and Patil (1983) [9] Where, WDC = Dry weight of weeds in unweeded control plot (g) WDt = Dry weight of weeds in the treated plot (g)

The experimental design data were statistically analysed using Fisher's analysis of variance approach, and treatment means were compared using an F-test and the least significant difference test at a 5% probability level to determine CD values. On all of the gathered data, analysis of variance was carried out. In sensitive species, it inhibits enzymes involved in chlorophyll and lipids synthesis by the combination of Fomesafen + Fluzifop-p-butyl controlled certain grasses, sedges and broad leaved weeds. T3 treatment followed by T4-Aciflurfen-sodium + Clodinafop-proparyl 245 g ha-1 with total weed density of 134.45 no.m -2 and total weed dry weight of 54.0 g m -2 and with weed control efficiency of 70.2 % at 30 DAS. Similar results were observed by Aher et al (2023) [1] . Among the weed management practices, T7 treatment (Two hand weedings at 15 and 30 DAS) observed complete removal of weeds. T8 treatment (unweeded check) recorded with the highest total weed density (247.75, 380 no. m -2 ) and total weed dry weight (82.90, 181.1 g m -2 ) at 15 and 30 DAS respectively.

Growth parameters

Among the weed management practices, T3-Fomesafen + Fluzifop-p-butyl 11.1%+11.1% SL (pre-mix) 220 g ha-1 PoE at 20 DAS treatment recorded significantly highest plant height (18.87cm) and total number of branches per plant (36.64) at harvest stage followed by T7-hand weeding twice at 15 and 30 DAS treatment. Whereas, significantly highest crop dry matter (245 g m -2 ) recorded in T7-hand weeding at 15 and 30 DAS treatment may be due to the complete removal of weeds at 15 and 30 DAS, which was followed by T3 treatment. The performance of T3 treatment (Fomesafen + Fluzifop-p-butyl 11.1%+11.1% SL (pre-mix) 220 g ha-1 PoE at 20 DAS) may have contributed to a reduction in crop-weed competition by significantly lowering total weed density and total weed dry weight at 30 DAS which may be the critical stage for black gram growth and development. Similar findings were noticed by Harisha et al 2021 [4] .

Yield attributes

It was observed that there is a significant effect of weed management practices on yield attributing characters of the crop including the number of pods branch-1, total number of pods plant-1, pod weight (g) and 100 seed weight (g). The highest average number of pods branch-1, total number of pods plant-1, pod weight (g) and 100 seed weight (g) was observed in T7-hand weeding twice at 15 and 30 DAS treatment (7.14, 20.00, 3.93, 6.53 and 3.93 respectively) followed by T3-Fomesafen + Fluzifop-p-butyl 220 g ha-1 at 20 DAS treatment (5.89, 18.13, 3.82, 6.34 and 3.85 respectively except no. of seeds plant-1). The results find support and similar findings were observed by Harisha et al., 2021 [4] and Suryavanshi et al. (2018) [12] . Better results for T7 treatment may be due to the clearance of complete weeds at most critical crop-weed competition (15-30 DAS) for black gram made available nutrients, space, moisture, etc. needed for better growth and development of the crop.

Yield parameters

Significantly highest seed yield (795 kg ha-1) and haulm yield (1485 kg ha-1) was recorded with hand weeding twice at 15 and 30 DAS treatment. Similar results were noticed by Sahoo et al.

(2017) [10] , and Nirala et al. (2016) [8] . Whereas, among the herbicidal treatments post-emergence application of Fomesafen + Fluzifop-p-butyl 220 g ha-1 at 20 DAS treatment recorded the highest seed yield (725 kg ha-1), haulm yield (1280 kg ha-1) and harvest index (37%) which was at par with post-emergence application of Aciflurfen-sodium + Clodinafop-proparyl 245 g ha-1 at 20 DAS (680 kg ha-1) and haulm yield (1234 kg ha-1). Jagadesh and Raju (2021) [5] , Yadav et al., 2022 [13] found that better weed control practices reduced the crop-weed competition created favourable conditions and produced better yields for the black gram.

Conclusion

Among the weed management practices, T7 treatment (hand weeding at 15 and 30 DAS) was superior in growth parameters, yield attributes and yield; recorded lower weed density, and lower weed weight. Among the herbicide-applied plots, postemergence application of Fomesafen + Fluzifop-p-butyl 11.1% + 11.1% SL (pre-mix) 220 g ha-1 at 20 DAS was found to be effective for controlling weeds, thereby enhanced crop growth and yield parameters, resulting in highest seed, haulm yield and harvest index.

Acknowledgement

I am greatly pleased to express my heartfelt gratitude to the Department of Agronomy, Agricultural College, Jagtial, PJTSAU.

References

1. Aher KP, Pawar SU, Koturwar MR, Gokhale DN. Efficacy of broad-spectrum post-emergence herbicide combinations in soybean (Glycine max L. Merrill). The Pharma Innovation Journal. 2022;12(1):735-738.
2. Balyan JK, Choudhary RS, Kumpawat BS, Choudhary R. Weed management in black gram under rainfed conditions. Indian Journal of Weed Science. 2016;48(2):173-177.
3. Gomez A, Gomez A. Statistical procedure for agricultural research. 2nd ed. New York: John Wiley & Sons; 1984.
4. Harisha S, Seenappa C, Lalitha BS, Raddy G, Pandu U. Bio-efficacy of new post-emergent herbicides on growth and yield of black gram. Indian Journal of Weed Science. 2021;53:107-110.
5. Jagadesh M, Raju M. Efficacy of sequential application of pre-and early post-emergence herbicides for management of weeds in black gram. Indian Journal of Weed Science. 2021;53(2):158-163.
6. Kumar N. Imazethapyr: A potential post-emergence herbicide for kharif pulses. Pulses Newsletter. 2010;21(3):5.
7. Kumar N, Hazra KK, Nath CP, Praharaj CS, Singh U. Grain legumes for resource conservation and agricultural sustainability in South Asia. In: Singh U, editor. Legumes for soil health and sustainable management. New Delhi: Indian Society of Pulse Research and Development; 2018. p. 77-107.
8. Nirala H, Sonit A, Rathore AL. Post-emergence herbicides for weed control in black gram. Indian Journal of Weed Science. 2016;48(1):76-78.
9. Patil VC, Patil SV. Studies on weed control in bamboo. Indian Journal of Weed Science. 1983;15:83-86.
10. Hepper) as influenced by weed control methods. Journal of Applied and Natural Science. 2017;9(2):693-697.
11. Singh RP, Verma SK, Singh RK, Idnani LK. Influence of sowing dates and weed management on weed growth and nutrients depletion by weeds and uptake by chickpea (Cicer arietinum) under rainfed condition. Indian Journal of Agricultural Sciences. 2014;84(4):468-472.
12. Suryavanshi T, Kewat ML, Lal S, Porte SS. Weed indices as influenced by propaquizafop and imazethapyr mixture in black gram. International Journal of Current Microbiology and Applied Sciences. 2018;7:738-744.
13. Yadav SL, Singh P, Yadav R, Dhaked U, Yadav G, Meena S, et al. Effective weed management for profitable mungbean [Vigna radiata (L.) Hepper] production in rainy season in South Eastern Rajasthan. The Pharma Innovation Journal. 2022;12(3):1014-1017.