Competitive Ability and Interference of Matricaria chamomilla in Direct-Seeded Carrot Under Different Crop Densities

Abstract

Competition from broadleaf weeds during early crop establishment can severely reduce productivity and market quality of direct-seeded carrot cultivation systems. Field experiments were conducted to evaluate the competitive ability and interference effects of Matricaria chamomilla on growth, yield components, and productivity of carrot under varying crop densities. Different carrot planting densities were established in combination with controlled weed infestations to assess crop–weed interactions throughout the growing season. Increased populations of M. chamomilla significantly reduced carrot seedling establishment, leaf area development, root biomass accumulation, and canopy expansion due to strong competition for light, nutrients, moisture, and growing space. Weed interference was most severe during early crop growth stages when carrot seedlings exhibited slow canopy development and limited competitive ability. Root yield, marketable root size, root length, and fresh weight declined progressively with increasing weed pressure, whereas higher carrot crop densities partially suppressed weed growth through enhanced crop canopy coverage and resource utilization. Competitive indices demonstrated that dense carrot stands reduced weed biomass and reproductive potential of M. chamomilla, although complete suppression was not achieved under high infestation levels. Seasonal observations indicated that environmental conditions favorable for rapid weed establishment intensified interference effects and reduced crop performance. Quality parameters of harvested carrot roots, including uniformity and commercial acceptability, were negatively affected by prolonged weed competition. The findings highlight the aggressive competitive nature of M. chamomilla in direct-seeded vegetable systems and emphasize the importance of optimizing crop density as part of integrated weed management programs. Combining appropriate sowing density with timely cultural and mechanical weed control measures may effectively reduce weed interference and improve carrot productivity.