Different weed management practices influence weed dynamics and productivity of maize (Zea mays L.)
摘要
Weed competition remains among the most critical biotic constraints limiting maize productivity, especially during early crop growth stages when slow canopy development and wide row spacing enable aggressive weed establishment. This study aimed to evaluate the efficacy of selected preemergence herbicides and manual weeding for managing weeds and enhancing crop performance under field conditions. A two-year field experiment (during the 2018 and 2019 seasons) was conducted at Norman E. Borlaug Crop Research Centre (NEBCRC), Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India, using a randomized block design with seven weed management treatments and three replicates. Treatments included T1: Metolachlor 50% EC at 1600 ml ha⁻1, T2: Metolachlor 50% EC at 2000 ml ha⁻1, T3: Metolachlor 50% EC at 2400 ml ha⁻1, T4: Diuron 80% WP applied at 1000 g ha⁻1, T5: Atrazine 50% WP applied at 2000 g ha⁻1, T6: Manual weeding performed twice, at 20 and 40 DAS, and T7: Weedy check. The results revealed that 50% EC with metolachlor at 2400 ml ha⁻1 (T3) resulted in superior and more sustainable weed suppression, reducing the total weed number, biomass, and weed control efficiency and the weed control index by more than 85% and > 90%, respectively, across major weed species. T3 significantly increased both grain yield and biological yield compared to other treatments. Nutrient uptake (N, P, and K) by maize was also highest under T3 and was statistically comparable to that observed with manual weeding. Additionally, T3 improved soil nutrient availability, microbial populations, and enzymatic activities. Overall, preemergence application of metolachlor at 2400 ml ha⁻1 emerged as an effective and practical weed management strategy in maize, especially under labour-scarce conditions.