A comparative analysis on efficacy of different herbicidal combinations in dry direct seeded rice condition

Abstract

Weeds pose a major challenge in Dry Direct-Seeded Rice (DDSR) because they thrive in oxygen-rich aerobic conditions. These weeds compete with rice plants for essential resources like nutrients, sunlight, and water. Integrated Weed Management (IWM) provides a sustainable solution to control weeds in DDSR. However, relying on a single herbicide or a combination of herbicides with similar modes of action can make weed control less effective. An experiment was conducted at KisanKraft’s R&D field located in Bengaluru Rural district of Karnataka during the Kharif 2024, to find the best herbicidal combination. The experiment was laid out in a Randomized Block Design (RBD) with two replications. Nineteen treatments, including combinations of pre and post-emergent herbicides, and a control with no herbicide, were planned. The pre-emergent herbicides included were: (1) Pendimethalin 30% EC, (2) Pretilachlor 50% EC, and (3) Metsulfuron-methyl 10% + Chlorimuron-ethyl 10% WP. The post-emergent herbicides included were (1) Bispyribac Sodium 10% SC, (2) Penoxsulam 1.02% + Cyhalofop-butyl 5.1% OD, (3) Fenoxaprop-p-ethyl + Ethoxysulfuron 15% WDG, and (4) Bentazone 48% SC. All 19 treatments significantly reduced weed growth. Among these, the combinations of Pretilachlor 50% EC + (Fenoxaprop-p-ethyl + Ethoxysulfuron 15% WDG) and Pendimethalin 30% EC + (Fenoxaprop-p-ethyl + Ethoxysulfuron 15% WDG) significantly reduced weed density and weed dry matter. This was supported by low Weed-Control Efficiency (WCE) and Weed Control Index (WCI) in these treatments.