Efficacy of post-emergence herbicides on weed dynamics, productivity and economics in spring planted sugarcane (Saccharum officinarum)

Abstract

Sugarcane is a major cash crop in India, playing a vital role in the country's agricultural economy. However, its productivity is often hampered by intense weed competition. Effective weed management is thus crucial to ensure optimal cane yield and profitability. To address this, a two-year field experiment (2023–24 and 2024–25) was conducted at Banaras Hindu University, Varanasi, India to assess the performance of the various post-emergence herbicide treatments in spring-planted sugarcane. The study was laid out in a randomized complete block design with nine treatments, including solo and tank-mix applications of 2,4-D sodium salt, ametryn, halosulfuron-methyl, mesotrione + atrazine, a premix of 2,4-D + ametryn + halosulfuron-methyl at three dose levels (3.5, 4.5, and 5.625 kg/ha), along with a hand-weeding treatment and an untreated control. The dominant weed flora observed in the field were Cyperus rotundus, Cynodon dactylon, Digitaria sanguinalis, Ipomoea aquatica, Sida acuta and Solanum nigrum. Among all the treatments, the premix of 2,4-D + ametryn + halosulfuron-methyl at 5.625 kg/ha recorded the highest weed suppression (96.27% WCE), cane yield (148 t/ha), net returns (₹4,05,260/ha), juice quality (24.63% brix), lowest weed density (3.01/m²) and minimum weed biomass (3.14 g/m²). The positive outcomes were also credited to reduced competition between crops and weeds, with no phytotoxicity. These findings highlight the weed control efficacy as post-emergence application (30 DAP) of ready-mix herbicide molecules (2,4-D + ametryn + halosulfuron-methyl at 5.625 kg/ha) which may be adopted by sugarcane growers, particularly under agro-climatic conditions of the eastern Uttar Pradesh.