秋灌模式和灌溉定额对不同盐碱度土壤的水盐分布影响研究OA

By investigating the patterns of water and salt transport in farmland soils with different salinization degrees under different autumn irrigation methods and irrigation quotas in the Alar reclamation area of Xinjiang,this study aimed to provide a scientific reference for saline-alkali land improvement and the formulation of rational autumn irrigation systems in the Alar reclamation area and arid regions of Xinjiang.Soil samples were collected from mildly salinized and severely salinized fields in the Alar reclamation area and indoor soil column leaching simulation experiments were conducted.Using mildly salinized and severely salinized soils as experimental materials,2 autumn irrigation modes,intermittent leaching and continuous leaching,were applied,with 3 irrigation quotas of 1 200,1 800,and 2 400 m3/ha.A full factorial experimental design was adopted to comparatively analyze the effect of different autumn irrigation methods and irrigation quotas on infiltration characteristics,as well as changes in soil moisture content and salinity at different depths before and after leaching.Results indicated that,when comparing autumn irrigation method and irrigation quota,the maximum vertical wetting front depth showed a strong correlation with irrigation quota but a weak correlation with irrigation method,and an effective irrigation quota threshold existed for wetting front development.Autumn irrigation quota significantly improved soil salinity distribution characteristics but had little effect on surface soil desalination rate.With increasing irrigation quota,both soil water and salt migration to deeper depth increased,exhibiting distinct stratification characteristics.When the irrigation quota was 1 800 or 2 400 m3/ha,the salinity differences among leaching layers with increasing irrigation amount were small,but they were markedly different from those under the irrigation quota of 1 200 m3/ha.Under the irrigation quota of 1 200 m3/ha,regardless of continuous or intermittent leaching,soil leaching in the root growth zone(0 to 40 cm)was insufficient.For the upper soil layer of the root growth zone(0 to 40 cm),intermittent leaching resulted in higher moisture content than continuous leaching,providing better water conditions for crop growth.For the mildly salinizedsoil samples,no significant difference in desalination was observed between continuous and intermittent leaching in the root growth zone(0 to 40 cm),but the salt content in accumulation layers under continuous leaching was higher than that under intermittent leaching.For severely salinized soil samples,intermittent leaching achieved more effective salt leaching than that in continuous leaching,and the burial depth of the salt accumulation layer was 10 cm deeper than that that under continuous leaching.In conclusion,intermittent leaching is recommended as the suitable autumn irrigation method for the Alar reclamation area in southern Xinjiang,with an optimal irrigation quota of 1 800 m3/ha.