Competitive Dynamics and Critical Period of Weed Control for Cyperus esculentus in Irrigated Potato Fields

Abstract

Competitive interactions between Cyperus esculentus and irrigated potato were evaluated to determine yield loss potential and the critical period of weed control under field conditions. Weed emergence patterns, crop–weed interference intensity, biomass accumulation, and tuber yield responses were quantified under varying durations of weed-free and weed-infested periods. Early-season competition exerted the greatest impact on potato growth, with prolonged interference resulting in significant reductions in plant height, canopy development, and tuber initiation. Yield loss increased progressively with delay in weed removal, indicating high sensitivity of potato to early weed pressure. Conversely, maintaining weed-free conditions during the initial growth stages substantially minimized yield penalties even when late-season weed emergence occurred. Regression analysis of relative yield loss suggested a well-defined critical period of weed control occurring during the early vegetative phase of potato growth, when resource demand and canopy establishment coincide. Aboveground and belowground biomass of C. esculentus was significantly reduced under timely weed removal treatments, highlighting competitive suppression through crop dominance. Irrigation regimes influenced weed vigor, with enhanced tuber propagation under adequate moisture conditions contributing to persistent infestation pressure. The results emphasize that integrated weed management strategies focusing on early intervention are essential for effective suppression of C. esculentus in irrigated systems. Identification of the critical period provides a decision-support framework for optimizing herbicide application timing and cultural control practices. These findings support the development of precision-based weed management programs aimed at minimizing yield losses while reducing reliance on repeated chemical inputs in potato-based cropping systems.