Construction of empirical model for water requirement in root zone salt leaching and its application in assessment of regional water supply and demand balance
This study aims to reasonably estimate the water requirement for leaching salts in the root zone,assess the balance of agricultural water resource supply and demand in typical saline-alkali soil areas,and propose suggestions and strategies for water resource utilization.Taking the saline-alkali soil in the Manas River Basin of Xinjiang and the Yellow River Delta as the backgrounds,and using the soil water movement dynamics equation(Richards equation)and salt movement dynamics equation(convection-dispersion equation)as tools,numerical simulations of soil water and salt movement were conducted under different combinations of factors such as initial water content,salt content,and irrigation amount.The relationships between these factors and soil desalination effects were analyzed,and empirical models for water requirement for salt leaching in the root zone suitable for different regions were constructed.Furthermore,the water supply and demand situations in these two regions were assessed,and recommendations and countermeasures were proposed.The results showed that,for both Manas Basin and Yellow River Delta,the soil salt content simulated based on the constructed empirical models for salt leaching requirement of the root zone matched well with the results simulated by the dynamic models.The coefficient of determination(R2)between them was not lower than 0.99,the root mean square error(RMSE)was not more than 0.33 g·kg-1,and the normalized root mean square error(NRMSE)was not more than 4.4%.The analysis of the balance between water supply and demand indicated that,to meet the agricultural water demand for planting,the annual water supply gaps in the Manas Basin and the Yellow River Delta were 1.372×109-1.909×109 m3 and 1.60×108-3.09×108 m3,respectively,accounting for 43.9%-61.0%and 28.1%-54.2%of the total water supply.The empirical models for water requirement for salt leaching in the root zone proposed in this article are reasonable and reliable.To meet the needs of agricultural planting and saline-alkali soil improvement,both the Manas Basin in Xinjiang and the Yellow River Delta should further optimize the allocation of irrigation water resources,vigorously develop water-saving irrigation technologies,and rationally develop and utilize unconventional water resources.Additionally,the expansion of oasis areas in the Manas Basin should be moderate,and the optimization and adjustment of planting structures in the Yellow River Delta are also effective measures to alleviate the intensifying shortage of regional water resources.
irrigation for salt-leachingthe Manas River Basinthe Yellow River Deltasaline-alkali landwater balance analysis
万方数据
维普
