Impact of establishment methods and weed control treatments on weed dynamics and yield of wheat

Introduction

Wheat (Triticum aestivum L.) is a vital cereal crop, serving as a staple food for much of the global population and contributing significantly to food security. Globally, wheat covers 221.94 million hectares, with a production of 780.05 million metric tons and productivity of 3510 kg/ha (USDA, 2021-22). In India, wheat occupies 30.54 million hectares, producing 106.41 million metric tons with a productivity of 3484 kg/ha (ICAR-IIWBR, 2021-22) [9] . Madhya Pradesh accounts for 5.99 million hectares, yielding 17.63 million metric tons at 3298 kg/ha (Department of Agriculture, M.P., 2020) [3] . Despite its adaptability, wheat faces biotic and abiotic stresses, with weed infestations causing 30-80% yield losses (Chauhan et al., 2012) [1] . Crop establishment methods; conventional tillage, reduced tillage, and zero tillage affect weed flora, density, and dry matter accumulation. Conventional tillage initially controls weeds but increases the weed seed bank (Hobbs et al., 2008) [8] . Reduced tillage preserves soil structure but faces higher weed pressure, while zero tillage minimizes soil disturbance but depends on herbicides (Friedrich et al., 2012) [6] . Herbicides are essential for modern weed management, but their overuse has led to herbicide-resistant weeds, threatening agricultural sustainability (Heap, 2014) [7] . This study examines the effects of establishment methods and weed control strategies on weed density, dry matter, and wheat yield, aiming to develop sustainable production practices.

Materials and Methods

The experiment was conducted during the rabi seasons of 2022-23 and 2023-24 at the Instructional Research Farm, Krishi Nagar, Adhartal, Department of Agronomy, Jawaharlal Nehru Krishi Vishwa Vidyalaya, Jabalpur (M.P.). A split-plot design with three replications was employed, comprising sixteen treatments derived from four establishment methods and four weed control treatments. The establishment methods included; zero tillage, zero tillage with chemical stale seedbed, conventional tillage and conventional tillage with stale seedbed.

The weed control treatments included four treatments; clodinafop + metsulfuron (60+4 g/ha, as post-emergence), mesosulfuron-methyl + iodosulfuron-methyl sodium (12+2.4 g/ha, as post-emergence), hand weeding at 20 and 40 DAS and weedy check Fertilizers (120 N: 60 P₂O₅: 40 K₂O kg/ha) were applied uniformly, with half of the nitrogen and all phosphorus and potassium as basal, and the remaining nitrogen in two splits after first and second irrigation. Weed data were collected randomly from five locations in each plot, and weeds were identified and counted species-wise. After recording the density, the collected weed samples were sun-dried for two days and then oven-dried at 60 ± 5°C for 48 hours to determine their dry weight. Weed control efficiency (WCE) and weed index (WI) were calculated using the following formulae:

Where, DWC = Dry weight of weeds in weedy check plot DWT = Dry weight of weeds in treated plot Where, X = Yield from weed-free plot Y = Yield from treated plot for which weed index is to be estimated Data on weed density and dry weight were transformed through square-root method [(×+0.5)½] before analysis of variance (ANOVA) to reduce the higher coefficient of variation in original/ observed data (Das, 1999) [2] .

Results and Discussion

The experimental field was infested with Phalaris minor (little canary grass), Medicago denticulata (tooth burclover), Chenopodium album (lambsquarters), Solanum nigrum (black nightshade), and other weed species. During both the years of the experiment, the density of Phalaris minor (141.00/m² and 170.33/m²) and Medicago denticulata (104.30/m² and 137.33/m²) was higher than that of Chenopodium album (35.00/m² and 49.00/m²) and Solanum nigrum (13.00/m² and 26.67/m²). Similar findings were reported by Jain et al. (2007) [10] in Jabalpur, Madhya Pradesh. Among the establishment methods, zero tillage resulted in the highest weed population and dry matter accumulation for both grassy and broadleaf weeds, with the lowest Weed Control Efficiency (WCE) at 60 DAS (37.50% in 2022-23 and 25.96% in 2023-24). In contrast, conventional tillage with stale seedbed consistently recorded the lowest weed population and dry matter accumulation, achieving the highest WCE (45.56% in 2022-23 and 39.37% in 2023-24), comparable to zero tillage with chemical stale seedbed (44.47% in 2022-23 and 37.10% in 2023-24). Among the weed control treatments, the weedy check exhibited the highest weed population and dry matter accumulation for all species, whereas hand weeding twice significantly reduced these parameters and achieved the highest WCE, reaching 55.10% at 60 DAS during 2022-23 and maintaining similarly high levels in 2023-24 (40.69%). Both herbicidal treatments; clodinafoppropargyl + metsulfuron-methyl and mesosulfuron + iodosulfuron-methyl sodium were highly effective in controlling weed populations and dry matter accumulation across all species. Specifically, clodinafop-propargyl + metsulfuronmethyl demonstrated effectiveness comparable to hand weeding for broadleaf weeds, while mesosulfuron + iodosulfuron-methyl sodium was more effective against the grassy weed (Phalaris minor). Similar associations of these weed species with wheat crops were reported by Sharma et al. (2020) [15] , Raj et al. (2024) [14] , and Mruthunjaya (2020) [13] .

References

1. Chauhan BS, Singh RG, Mahajan G. Ecology and management of weeds under conservation agriculture: A review. Crop Prot. 2012;38:57-65. DOI: 10.1016/j.cropro.2012.03.010.
2. Das TK. Is transformation of weed data always necessary? Ann Agric Res. 1999;20(3):335-341.
3. Department of Farmer Welfare and Agriculture Development, Madhya Pradesh. Agricultural statistics of Madhya Pradesh. In assistance with the Ministry of Agriculture, Government of India. 2020. Available from: https://mpkrishi.mp.gov.in/Englishsite_New/indexEnglish_ New.aspx
4. FAO. The State of Food and Agriculture 2021. Food and Agriculture Organization of the United Nations. Rome, Italy; 2021.
5. FAS, USDA. U.S. Department of Agriculture Foreign Agricultural Service Global Market Analysis. World Agricultural Production 2024. Available from: https://www.fas.usda.gov/data/world-agriculturalproduction
6. Friedrich T, Derpsch R, Kassam A. Overview of the global spread of conservation agriculture. Field Actions Sci Rep. 2012;6:1-7.
7. Hobbs PR, Sayre K, Gupta R. The role of conservation agriculture in sustainable agriculture. Philos Trans R Soc B Biol Sci. 2008;363(1491):543-555. DOI: 10.1098/rstb.2007.2169.
8. ICAR-IIWBR. Progress Report of AICRP on Wheat and Barley 2021-22, Social Sciences. Eds: Satyavir Singh, Anuj Kumar, Sendhil R, Anil Kumar Khippal, Raj Kumar, GP Singh. ICAR-Indian Institute of Wheat and Barley Research, Karnal, Haryana, India; c2022. p. 37.
9. Jain N, Mishra JS, Kewat ML, Jain V. Effect of tillage and herbicides on grain yield and nutrient uptake by wheat (Triticum aestivum) and weeds. Indian J Agron. 2007;52(2):131-134.
10. Kumari S, Kumar D, Kumar S, Dutta SK, Chandini, Verma K. Assessing the soil properties under conservation agriculture-based tillage practices in a cereal-based cropping system of Bihar. Pharma Innov J. 2021;10(10):711-714.
11. Kushwah SS. On-farm assessment of ready-mix herbicide combinations for broad-spectrum weed control in wheat. Indian J Weed Sci. 2020;52(2):194-196.
12. Maruthyunjaya. Impact of tillage (zero & conventional) and weed management practices on weed dynamics and yield of wheat (Triticum aestivum L.). Thesis submitted to Department of Agronomy, BHU Varanasi; 2020.
13. Raj R, Das T, Chakraborty D, Bhattacharyya R, Babu S, Govindasamy P, et al. Soil physical environment and active carbon pool in the rice-wheat system of South Asia: Impact of long-term conservation agriculture practices. Environ Technol Innov. 2023;29:102966.
14. Sharma N, Kumar A, Sharma BC, Chand L, Sharma V, Kumar M. Effects of sowing dates and weed management on the productivity of irrigated wheat. Indian J Agric Sci. 2020;90(3):556-559.