多点源滴灌条件下红壤水分溶质运移试验与数值模拟

Movement and Numerical Simulation of Soil Water Solute Migration under Multipoint Drip Irrigation in Red Soil

摘要:

为了掌握红壤多点源滴灌条件下水分溶质运移规律，为红壤丘陵地区脐橙滴灌灌溉设计和管理提供参考，建立了5个不同红壤容重下滴灌水分和硝态氮运移的数学模型。借助Hydrus-3D模型模拟了不同红壤容重、同一滴头流量和施氮量时土壤水分溶质分布特征和湿润锋推移和交汇过程。模拟结果与试验对比表明：模拟的湿润锋运移交汇过程、湿润体内土壤含水率以及NO-3-N含量与实测值之间的偏差均在9.5%以内；模拟值和实测值具有很好的一致性，并显示在湿润锋交汇处土壤含水率和NO-3-N含量低于同一深度滴头下方的土壤，另外高容重红壤阻碍湿润锋的推进速度。总体而言，Hydrus-3D可以用于红壤滴灌施肥灌溉条件下湿润体范围以及水分和氮素运移和分布的模拟。

Abstract:

In order to grasp the movement law of soil water and solute in dual point source drip irrigation, and provide reference for the design and management of drip irrigation of navel orange in red soil hilly areas, a mathematical model for water and nitrate nitrogen transport in five different red soil bulk densities was established. With the help of Hydrus-3D model, the soil water and solute distribution characteristics and wetting front transition and confluence process were simulated under the different red soil unit weights, the same drip discharge and nitrogen application rate. The simulation results were in good agreement with the test results: the deviations of simulated wetting front migration and confluence process, wetting zone soil moisture content and NO-3-N content between the measured and simulated values were less than 9.5%;the simulated and measured values were in good agreement, and it showed that the confluence of soil moisture and NO-3-N content in the same depth was below the wetting front under the drip soil, and red soil in high density hindered the wetting front velocity. Overall，Hydrus-3D can be used to simulate the wetting zone and the transport and distribution of water and nitrogen under drip irrigation fertilizer irrigation and red soil irrigation.