Ecology, Environment and Conservation Paper

EVALUATION SWAP MODEL IN PADDY FIELD UNDER IRRIGATION MANAGEMENT

Ebrahim Amiri

Abstract

The SWAP model was evaluated against a data set of four irrigation management, the study was laid out in RCBD and 3 replications for one popular traditional landrace Hashemi carried out in 2005 at Rice Research Institute of Iran, Rasht. The irrigation management was I1 with continuous irrigation while 12, 13 and 14 were irrigation 1, 3 and 5 days after water disappearance of ponded water. SWAP model simulate of water flow, To calculate soil water flow, SWAP employs Richard's equation for soil water movement in the soil matrix. Measurements of the soil water content were taken using TDR for 4 water management. For evaluation model are compared simulated and measured soil water content, leaf area index (LAI) and biomass of panicles, and total aboveground biomass by absolute and normalized root mean square errors(RMSE). On average, RMSE of model were 501-736 kg ha-1 for total biomass, 148-364 kg ha-1 for panicle biomass, and 0.47-0.62 cm2cm-2 for LAI. For these crop variables, normalized RMSE values were 13-21 for total biomass, 6-18 for panicle biomass and 93-55 for LAI. The model Simulated LAI generally exceeded measured values. The root mean square error (RMSE) range of soil water content was 0.016-0.062 crn3cm-3 and normalized root mean square errors (RMSEn) was 3-6 %.