摘要
为了探究浑水膜孔灌肥液入渗在不同土壤初始含水率下水氮运移特性,通过室内肥液入渗试验,研究了不同土壤初始含水率(6.02%,7.40%,8.23%,10.08%和13.20%)条件下入渗特性、湿润锋运移、土壤水分分布以及铵态氮和硝态氮的运移特性,建立了浑水膜孔灌肥液入渗累积入渗量、各向湿润锋运移距离与土壤初始含水率之间的关系,提出了不同土壤初始含水率的累积入渗量以及各向湿润锋运移距离的经验模型。结果表明:累积入渗量、各向湿润锋运移距离以及湿润体内水分和氮素的分布规律均受到土壤初始含水率的影响;同一入渗时刻,累积入渗量随土壤初始含水率的增大而减小,而湿润锋运移距离却呈现出随时间增大的趋势;土壤初始含水率越大,湿润体体积越大,湿润体内水分、铵态氮以及硝态氮分布范围越广;土壤初始含水率越大,入渗系数K值越小,入渗指数α越大。灌水结束时,湿润体内铵态氮绝大部分分布在湿润体半径r≤5cm范围内,而湿润体半径10cm>r>5cm范围的土壤铵态氮含量随土层深度的增加而降低,当湿润体半径r≥10cm时,铵态氮含量明显降低;硝态氮主要集中分布在由膜孔中心至半径为10cm范围内,水平方向和垂直方向硝态氮含量均随着膜孔中心距离的增加而降低,距离膜孔中心越近硝态氮含量越高;在同一位置处,铵态氮和硝态氮质量分数均随土壤初始含水率的增大而增大;随土壤水分再分布,湿润锋逐渐下移,湿润体内铵态氮逐渐向下运移且其含量呈现降低趋势;随时间继续运移,上层土壤硝态氮含量逐渐减小,下层新湿润体中硝态氮含量逐渐增加,整个湿润体内硝态氮含量分布趋于均匀。研究成果为进一步研究浑水膜孔灌肥液入渗氮素运移及转化奠定了基础。
In order to explore the water and nitrogen transport characteristics under water and fertilizer integration of film hole irrigation with muddy water irrigation,through the indoor fertilizer infiltration test,the migration characteristics of infiltration wetting front migration,soil moisture,ammonium nitrogen and nitrate nitrogen were studied under different soil initial water content（6.02%,7.40%,8.23%,10.08% and 13.20%）.The relationship between cumulative infiltration volume,the wetting front migration distance and the soil initial water content of liquid fertilizer infiltration of film hole irrigation with muddy water were established.An empirical model was proposed to calculate the cumulative infiltration volume and the wetting front migration distance under different soil initial water content.Results showed that：The cumulative infiltration,the wetting front migration distance,the water transport in wetting body,the distribution and transformation of nitrogen were all affected by the soil initial water content.At the same infiltration time,the cumulative infiltration reduced,while the wetting front migration distance increased,with the increase of soil initial water content.The higher the soil initial water content was,the larger the wetting volume was,and the wider water,ammonium nitrogen and nitrate nitrogen in soil distributed.The higher the soil initial water content was,the smaller the value of infiltration parameter K was,and the larger the value of infiltration indexαwas.After irrigation,ammonium nitrogen was mostly distributed in the wetting body with humidradius which was less than or equal to the range of 5 cm.Meanwhile,ammonium nitrogen content decreased with the increase of soil depth in the wetting body when the wetted radius was larger than 5 cm and less than 10 cm.The ammonium nitrogen content obviously decreased when the humid radius was larger than 10 cm.Nitrate nitrogen was mainly distributed in the range from the center of the membrane pore to the wetting radius of 10 cm.The nitrate nitrogen content in the horizontal direction and the vertical direction decreased with increasing distance from the center of the film hole,the nearer was away from film hole center the higher nitrate nitrogen content was in both vertical and horizontal direction.The greater the initial soil water content was,the higher the mass fraction of ammonium nitrogen and nitrate nitrogen was at the same position.With the redistribution of soil moisture,the wetting front gradually went down,the wetting of ammonium nitrogen gradually downwardly migrated and its content decreased.Nitrate nitrogen concentration front transported with time prolongation,the soil nitrate nitrogen content decreased in the upper layer and gradually increased in the lower layer new wetting body,the content of nitrate nitrogen in wetting body tend to uniformly distribute.The research results could lay the foundation for further study on the transport and transformation of nitrogen fertilizer under the film hole irrigation with muddy water.
作者
陈琳
费良军
刘利华
王子路
钟韵
CHEN Lin;FEI Liangjun;LIU Lihua;WANG Zilu;ZHONG Yun(Institute of Water Resources and Hydro-electric Engineering, Xi＇ an University of Technology, Xi＇an 710048;Yellow River Institute of Hydraulic Research, Zhengzhou 450003)
出处
《水土保持学报》
CSCD
北大核心
2018年第2期58-66,共9页
Journal of Soil and Water Conservation
基金
国家自然科学基金项目(51479161
51779205)
国家重点研发计划项目(2016YFC0400204)
陕西省教育厅项目(16JK1539)
中国博士后基金项目(2015M582763XB)
中央级公益性科研院所基本科研业务费专项(HKY-JBYW-2016-26)
关键词
浑水膜孔灌
土壤初始含水率
水分再分布
模型
氮素运移
film hole irrigation with muddy water
soil initial water content
water redistribution
models
nitrogen migration
