Competitive Dynamics and Critical Period of Weed Removal for Setaria viridis in Irrigated Maize Fields

Abstract

Maize is a globally important cereal crop, but its productivity is often constrained by weed competition during early growth stages. Setaria viridis (green foxtail) is a highly competitive grassy weed that significantly reduces maize yield by competing for light, nutrients, water, and space, particularly in irrigated production systems. Understanding its competitive dynamics and identifying the critical period of weed removal are essential for effective weed management and yield optimization. The present study was conducted to evaluate the competitive interactions between maize and S. viridis and to determine the critical period for weed removal under irrigated field conditions. Field experiments were designed with varying durations of weed interference and weed-free periods to assess their effects on crop growth, yield components, and final grain yield. Data on weed density, weed biomass, maize growth parameters, and yield loss were recorded and analyzed. The results indicated that S. viridis competition during early growth stages of maize caused significant reductions in plant height, leaf area development, and grain yield. Yield loss increased with prolonged weed interference, while early weed removal substantially improved crop performance. The critical period for weed removal was identified as the early vegetative phase of maize, during which weed control is essential to prevent irreversible yield losses. Delayed weed removal beyond this period resulted in substantial yield penalties due to early competition effects. The findings highlight the aggressive competitive ability of S. viridis in irrigated maize fields and emphasize the importance of timely weed management. Integration of early-season weed control strategies is crucial for minimizing crop–weed competition and ensuring sustainable maize production. The study provides valuable insights for optimizing weed management schedules in irrigated maize-based cropping systems.