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With the increasing development of irrigation methods, research on the impact of these methods on soil salinity needs to be carried out. To understand the salinity distribution in the root zone, time-consuming and costly field experiments are required, which have some limitations, while the models are able to accurately evaluate the condition by simulating water movement conditions in the porous medium. Among the simulation models, the LEACHC model simulates the movement of water, salts, as well as the absorption of roots and chemical interactions in a non-saturable soil in a one-dimensional aspect. The aim of this project was simulation of salinity movement in soil profile and identification of the effect of sprinkler, droplet and surface irrigation on salinity movment in selected farms and gardens. The sites of the projectwere fields and gardens located in selected three provinces of Alborz, Semnan and Mazandaran, respectively, represent semi-dry, dry and semi-humid climate. In the above mentioned selection of the sites, the existence of sprinkler, droplet and surface irrigation systems, preferably more than five years after its exploitation, and the results of soil experiments in the early studies, have been considered. In order to study the effect of drip irrigation, sprinkler and surface irrigation on solute motion, soil profiles were drilled and described with three replications up to a depth of 1.5 m. To simulate the solute movement, initial conditions of moisture, salinity and monitoring of their variations during the crop season or simulation period in the soil profile should be taken into consideration. Soil sampling was conducted to investigate more precisely the distances between rainfall and irrigation. Finally, using LEACHC and LEACHW models using the available data in the region, the estimated salinity and moisture content of the model were evaluated with measured salinity values. he results were analyzed by a comparison of means. Regarding the significance of the difference between estimated values of the model and observational values, the sensitivity analysis of the model was carried out in 6 farms from a total of 11 farms and the model was again performed on the basis of calibrated parameters. In this project, salinity changes in soil profile during the growing season and the next 5 years were predicted. So, in the semi-humid region (Dasht-e-Naz Sari) with heavy texture, the amount of insignificant salinity decreased, the salinity class did not change in the surface and bottom horizons of the soil and remained in the class S0. In other words, it can be said that the development of new systems in these areas (provided other conditions) will not limit the soil salinity. In the semi-arid region (Alborz) with moderate texture, the salinity increased, the salinity class did not change in the surface and bottom horizons of the soil and remained in the class S0. Soil salinity in these lands will not even limit the cultivation in the next five years. The occurrence of rainfall in the seasoned season has led to the control of soil salinity and keeping it to an acceptable level. In the dry zone (Semnan) with light texture, increasing the salinity of the soil in the surface horizons under the pressure of irrigation management will change the salinity class in the next 5 years (from S1 to S2). Salinity levels have also increased in subtropical horizons, which in some fields has changed the salinity class from S1 to S2. In general, it can be said that irrigation management in the studied fields should be applied in such a way that the soluble soluble soils do not have the opportunity to concentrate and to accumulate in the soil. So, in irrigated areas, irrigation pattern correction (irrigation at low intervals), soil leaching in cold seasons, observance of principles to crops and use of cultivars resistant to salinity and dehydration can be corrected and prevented from soil degradation.Key words: Irrigation Systems, Salinity, Alborz, Semnan, Mazandaran, LEACHC Model, Land Management
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