evaluation of the swap model to estimate the distribution pattern of soil moisture under drip irrigation management

abstract assessing moisture in the soil under cultivation of crops to achieve high performance and reduced water are necessary. knowledge of the moisture distribution in the root zone, time consuming and costly field tests that simulation models, a suitable alternative in answer to issues of movement and are water distribution. in this study assessment of soil moisture, to aid swap simulation model was and above model empowerment compared with field results was assessed. swap model based on the information in a field irrigated onion, equipped with drip irrigation systems and soil hydraulic parameters obtained from model retc, were performed. moisture information with harvest soil from emitter place and 10 cm of the layers 15-0, 30-15, 45-30 and 60-45 were obtained. comparison of simulated moisture with observations moisture to a depth of 60 cm in the emitter place and 10 cm it, in the form of graphs and calculation criteria of root mean squared error (rmse), root mean squared error of normal (nrmse) and mean absolute error (mae) was performed. values of rms, rrmse and mae in the normal place dropper 0.001, 0.03 and 0.07 cm3cm-3 and in 10 cm were 0.08, 0.02 and 0.07 cm3cm-3, respectively. low errors calculated from the model swap, shows good accuracy of the model simulated moisture distribution in the root zone. operations irrigation through a drip irrigation system, with irrigation 48 hours was equivalent to performance kg/ha 14780 against 14134 kg/ha estimated by the model will follow. in total, the results indicate that the swap model is able to respond with a valid enough accuracy and precision in a relatively short time to provide. this model can be as effective and useful tool for evaluating and optimizing the distribution of moisture in the root-crop area, used.