Investigating the Effect of Crop Pattern on Prevention of Drainage of Dasht_e_Abbas Land Using Dynamic System Approach

Selection of crop pattern is one of the most important factors in achieving water resources Sustainability. Due to the quantity and quality of soil and water, unsuitable and non-native plants may cause saltinification and elevation of groundwater level in the plant growth environment and degrade soil structure. And consequently reduce performance. Based on the dynamics of irrigation and drainage network in the Dasht-e-Abbas, located along the Karkheh Dam and Ilam province, in terms of quantity and quality of water in different scenarios of the crop pattern, using the system dynamics approach has been evaluated. Considering the information needed in this method, the boundaries of the system, the creation of a conceptual model, the determination of causative and causal relationships, the determination of the variables and verification based on observational information, structural testing, boundary test, and statistical parameters and the proposed cultivation pattern have been studied. The conceptual model was considered based on five sub-models of water demand, water supply, environmental stress, water economics and environmental issues. The results of this model show that in sensitivity analysis of input parameters, the coefficient of return of agricultural water to the aquifer has a great effect and its increase will increase the static volume of aquifer and increase the quality of groundwater due to dilution and also reduce the salinity of the soil due to Leaching. From other results of this study, using a crop pattern with an emphasis on increasing forage levels that prevents land drainage in the long time will improve soil construction.