Functional Traits Analysis and Competition Coexistence in Crops- Invasive Weeds Interaction Under Induced Salt Stress

Abstract

Weeds are an important component of agroecosystems that interact with crops and negatively affects food crop production through competition for light, soil nutrients and reduces yields of major crops by a global average of 34%. This study examines functional traits and competition analysis of Solanum lycopersicum and Capsicum annuum in mono and mixed culture with two invasive alien weeds (Euphorbia heterophylla and Acanthospermum hispidum) under different sodium chloride (NaCl) concentrations. Data for the study was obtained from field measurement and laboratory experiment. Results from the study showed that canopy height was significantly higher in monoculture at 5% NaCl concentration for both S. lycopersicum 88.23±1.12 and C. annuum 70.13±6.40, while the lowest values were recorded at higher salinity levels in mixed cultures. Leaf dry matter content and relative water content remained relatively stable across treatments, with the highest values observed in monoculture at 5% to 25% salinity. Specific leaf area exhibited variability, being highest in the mixture of S. lycopersicum and A. hispidum mixtures with 35.02±22.80 at 10% NaCl treatment and C. annuum and A. hispidum mixtures with 27.56±11.37 at 25% NaCl treatment. Yield was significantly higher in the S. lycopersicum and A. hispidum at 15% NaCl treatment with 1.41±0.01 and in C. annuum monoculture at 5% NaCl with 0.65±0.10. Relative yield and relative yield total followed similar trends, with the highest values recorded in optimal salinity. It is therefore concluded that the competitive balance between invasive weeds and crops is partially altered and also recommended that further studies should be carried out to identify the mechanism of intraspecific trait variation in weeds and the consequences of weed fitness.