Growth Analysis and Competitive Indices of Convolvulus arvensis Interfering with Sunflower at Different Densities

Abstract

Convolvulus arvensis is a highly competitive perennial weed that significantly reduces sunflower growth, yield, and resource utilization efficiency under field conditions. The present study evaluated the growth analysis and competitive indices of C. arvensis interfering with sunflower at different weed densities. Field experiments were conducted under varying weed population levels to assess their impact on sunflower growth parameters, including plant height, leaf area, dry matter accumulation, and yield components. Weed growth attributes such as biomass production, canopy spread, and resource uptake were also analyzed to determine competitive interactions between weed and crop. The results indicated that increasing density of C. arvensis significantly enhanced its competitive pressure on sunflower plants, leading to reduced growth performance and yield reduction in the crop. Higher weed densities resulted in increased suppression of sunflower biomass accumulation and decreased light interception efficiency due to aggressive spatial competition. Competitive indices revealed a strong dominance of C. arvensis over sunflower in early growth stages, primarily due to rapid root expansion and efficient resource acquisition. At lower densities, the negative impact on sunflower growth was comparatively reduced, indicating a density-dependent relationship between weed interference and crop performance. Growth analysis further demonstrated that weed presence altered physiological efficiency and reduced net assimilation rate in sunflower plants. The study highlights the importance of understanding weed–crop competition dynamics for developing effective weed management strategies. The findings provide valuable insights into density-dependent competitive interactions and support the implementation of integrated weed management practices aimed at minimizing yield losses in sunflower cultivation systems.