微润灌施下压力水头对湿润锋及土壤水氮运移的影响  

Effects of Pressure Head on Moisture Front and Soil Water and Nitrogen Transport under Moistube Irrigation

作　　者：李慧敏 申丽霞[1] 王瑞军 孟涵 李京玲[1] 孙雪岚[1] LI Hui-min;SHEN Li-xia;WANG Rui-jun;MENG Han;LI Jing-ling;SUN Xue-lan(College of Water Resources Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]太原理工大学水利科学与工程学院,太原030024

出　　处：《节水灌溉》2022年第9期81-86,92,共7页Water Saving Irrigation

基　　金：山西省自然科学基金项目(201901D111059,202103021204093)。

摘　　要：为探究微润灌施肥条件下压力水头对湿润锋运移距离及湿润体内水氮运移规律的影响,进行室内土箱模拟试验,设置5个水头(1 m、1.25 m、1.5 m、1.75 m和2 m),以浓度为600 mg/L的硝酸铵钙作为灌溉施肥,研究湿润锋运移距离与压力水头的关系,分析不同压力水头下湿润体内水氮运移规律。硝态氮(NO_(3)^(-))是植物吸收氮的主要形式,研究土壤中硝态氮的运移规律,对研究不同压力水头下微润灌的室外种植试验具有指导意义。试验结果表明:在微润灌施硝酸铵钙条件下,湿润体纵剖面为圆形,且湿润锋的运移距离与灌水时间均符合幂函数关系,入渗系数a与压力水头呈正相关关系,入渗指数b与压力水头呈负相关关系。压力水头对土壤水分运移有促进作用。压力水头越大,入渗界面的压力势越大,土壤水分入渗速率越快,同一时刻相同深度土层的含水率越大,累积入渗量越大。累积入渗量与灌水时间符合Kostiakov经验入渗公式,参数a、b与压力水头均为正相关关系。硝态氮运移规律与水分运移规律相反,距离微润管越远,土壤中硝态氮含量越高。压力水头对硝态氮运移有促进作用,同一时刻相同土层深度,压力水头越大,氮素运移越快,土壤平均硝态氮含量越高。硝酸铵钙能够改变土壤的孔隙结构。硝酸铵钙中钙离子与土壤胶体发生中和反应,导致土壤团粒结构增加,孔隙率增大,土壤入渗能力增强,在一定程度上可减小土壤入渗能力的衰弱速度,因此在大面积施用时,要避免其淋溶累积对水体及环境造成危害。微润灌施的推广与使用,仍然需要不断深入研究。In order to explore the influence of pressure water head on the migration distance of wetting front and the law of water and nitrogen migration in wetting body under the condition of moistube irrigation and fertilization,an indoor soil chamber simulation test was carried out Five water heads(1 m,1.25 m,1.5 m,1.75 m and 2 m)were set,and calcium ammonium nitrate(600 mg/L)was used as irrigation fertilizer The relationship between the migration distance of wet front and pressure head was studied and the law of water and nitrogen migration in moist body under different pressure head was analyzed.Nitrate nitrogen(NO_(3)^(-))is the main form of nitrogen absorption by plants.The study of nitrate nitrogen migration in soil is of guiding significance to the outdoor planting experiment of micro-irrigation under different pressure water head.The experimental results show that under the condition of moistube irrigation with calcium ammonium nitrate,the longitudinal profile of the wetting body is round,and the migration distance of the wetting front and the irrigation time are in line with the power function relationship.The infiltration coefficient A is positively correlated with the pressure head,and the infiltration index B is negatively correlated with the pressure head.Pressure head can promote soil water transport.The higher the pressure head,the higher the pressure potential at the infiltration interface,the faster the infiltration rate of soil water,the greater the water content of the soil layer at the same depth at the same time,and the greater the cumulative infiltration amount.The cumulative infiltration amount and irrigation time accord with Kostiakov′s empirical infiltration formula,and the parameters A and B are positively correlated with the pressure head.The law of nitrate nitrogen transport is contrary to the water transport law,the farther away from the micro-run pipe,the higher the nitrate nitrogen content in the soil The pressure head can promote the transport of nitrate nitrogen.At the same time and the

关 键 词：微润灌 压力水头 湿润锋 水氮运移 硝酸铵钙 累积入渗量 硝态氮 

分 类 号：S275[农业科学—农业水土工程]