Simulation of Bean (Phaseolus vulgaris L.) Yield Loss Caused by Jimson Weed (Datura stramonium L.) Interference by Empirical Competition Models

Document Type : Research Article


Bu-Ali Sina University


Use of empirical competition models is one of approaches in integrated weed management strategies. In order to investigation of this approach in simulation of yield loss of bean (Phaseolus vulgari. L.) caused by jimson weed (Datura stramonium L.) interference, an experiment was conducted in National Bean Research Station, in Khomein, in 2007. The experiment design was randomized complete blocks with a factorial arrangement in three replications. Treatments were combination of four different weed densities (4, 8, 12 and 16 plant m-1) and three times of weed emergence (with crop emergence, in first trifoliate leaf stage and third trifoliate leaf stage of bean), with a weed free bean (40 plant m-1) treatment as control. Three empirical competition models based on weed density (WD), relative time of weed emergence (RTW) and relative weed leaf area (RWL) were used in order to simulate crop yield losses. Results showed that the RWL model with highest coefficient of determination (R2= 0.90) and lowest remain mean squares (RMS= 0.05) has the best estimation of bean yield loss. The RTW model (with R2= 0.89 and RMS= 67.43) was located after it. However the simulation of WD model was acceptable just in separate times of weed emergence. Results also indicated that jimson weed threshold densities based on economic damage (7% of bean yield loss) were 0.84, 1.4 and 2.5 plant m-1 in first to third relative time of emergence, respectively. According to relative damage coefficient parameter in RWL model (q =2.59 0.29), it was demonstrated that jimson weed was the dominant plant in weed-crop competition system.

Key words: Bean, Competition, Datura, Empirical models, Simulation, Weed