Competitive Effects of Sorghum halepense Rhizome Density on Growth and Yield of Irrigated Maize

Abstract

Infestation of Sorghum halepense in irrigated maize fields poses a major challenge due to its vigorous rhizomatous growth and strong competitive ability for essential resources. Field experiments were conducted to evaluate the effects of varying rhizome densities of S. halepense on growth performance, yield components, and productivity of irrigated maize. Different rhizome infestation levels were established prior to crop sowing to assess crop–weed interactions throughout the growing season. Increasing rhizome density significantly reduced maize plant height, leaf area development, chlorophyll content, and biomass accumulation because of intense competition for light, nutrients, moisture, and space. High weed density also delayed crop development and suppressed root growth, leading to reduced nutrient uptake efficiency. Yield-related parameters including cob length, kernel number per cob, thousand-kernel weight, and grain yield decreased progressively with increasing S. halepense infestation. Severe rhizome populations caused substantial reductions in harvest index and overall crop productivity. The aggressive underground rhizome network enabled rapid weed regeneration and sustained competitive pressure during critical stages of maize growth. Environmental conditions associated with adequate irrigation and warm temperatures favored rapid expansion of rhizome shoots and increased weed dominance within the field. Competitive indices indicated that early establishment and perennial growth habit of S. halepense contributed significantly to its interference potential in irrigated maize systems. Lower maize yields under dense rhizome infestations demonstrated the economic importance of timely and effective weed management interventions. Integrated management approaches combining cultural practices, strategic tillage, and appropriate herbicide applications may reduce rhizome persistence and improve maize productivity.