单 位：
西安理工大学水利水电学院;西安理工大学省部共建西北旱区生态水利国家重点实验室
关键词：
含沙率;浑水;膜孔灌;肥液入渗;水氮运移
摘 要：
为研究浑水膜孔灌条件下含沙率对膜孔灌肥液入渗土壤水氮运移特性的影响,通过室内膜孔入渗试验,设5个含沙率水平(0、3%、6%、9%、12%),观测累积入渗量、湿润锋运移距离、湿润体内水分以及NO-3-N和NH4+-N运移变化特性。结果表明:浑水含沙率越大,湿润锋运移距离越小,相同入渗历时内湿润体体积和高含水率区域越小,湿润体内同一位置处土壤含水率越小。单位膜孔面积累积入渗量与入渗时间符合Kostiakov模型(R2>0.9,P<0.01);随着浑水含沙率的逐渐增大,入渗系数逐渐减小,而入渗指数基本不变。垂直湿润锋运移距离和减渗率均与入渗时间呈极显著的幂函数关系,含沙率对减渗率的影响主要是通过对减渗系数的影响来实现。湿润体土壤NO-3-N和NH4+-N含量随着浑水含沙率的增大而减小,且在膜孔中心附近区域其含量均较高。土壤NO-3-N主要集中分布在湿润半径10 cm范围内,湿润体水平方向及膜孔垂向土壤NO-3-N含量均随着距膜孔中心距离的增加而降低;而土壤NH4+-N主要集中分布在湿润半径5 cm范围内,湿润半径5～10 cm范围内的土壤NH4+-N含量随着土壤深度的增加而降低。研究结果可为进一步深入研究浑水膜孔灌肥液入渗提供理论依据。
译 名：
Effects of sediment concentration of muddy water on water and nitrogen transport characteristics under film hole irrigation with fertilizer infiltration
作 者：
Liu Lihua;Fei Liangjun;Chen Lin;Hao Kun;State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology;Institute of Water Resources and Hydro-electric Engineering, Xi'an University of Technology;
关键词：
sediment concentration;;muddy water;;film hole irrigation;;fertilizer infiltration;;water and nitrogen transport
摘 要：
Plastic film mulching is an effective agricultural measure to restrain soil water evaporation in the arid and semiarid regions of Western China. Based on the plastic film mulching cultivation, muddy water film hole irrigation is an advanced low-cost and high-efficiency irrigation method, which can improve water conservation, increase soil temperature, crop yield and economic efficiency. Therefore, understanding the distribution and transportation characteristics of water and nitrogen under plastic film mulching with muddy water fertilizer irrigation plays an important role to rationally use muddy water. The purpose of this study was to disclose the effects of the sediment concentration on transport characteristics of soil water and nitrogen under muddy water film fertilizer solution free infiltration. The laboratory soil-box experiments were conducted with muddy water film hole irrigation, using five sediment concentration treatments(0(CK), 3%, 6%, 9% and12%). Ammonium calcium nitrate(5 Ca(NO3)2·NH4 NO3·10 H2 O) was selected as the fertilizer to be tested, and it was dissolved in muddy water for film hole irrigation infiltration experiment. The fertilizer solution concentration was 600 mg/L. The cumulative infiltration volume, migration distance of the wetting front, soil moisture content and NO-3-N and NH4+-N contents in the wetted body were observed. The models about:(i) the relationships between the cumulative infiltration volume per unit film hole area and infiltration duration;(ii) the relationship among the vertical migration distance of the wetting front, sediment concentration and infiltration duration were established. The experimental results showed that the sediment concentration had a significant effect on the transport characteristics of soil water and nitrogen. Cumulative infiltration volume per unit film hole area and infiltration duration conformed to Kostiakov model(R2 > 0.9, P < 0.01). With the increase of sediment concentration in muddy water, the infiltration coefficient K decreased gradually, and the infiltration index remained unchanged. The relationship among vertical migration distance of the wetting front and infiltration reduction rate and infiltration duration was a very significant power function. The influence of sediment concentration on the infiltration reduction rate was mainly realized by the influence of the infiltration decay coefficient. Within the same infiltration time, the larger the sediment concentration of muddy water, the smaller the volume of the wetted body and the area with high moisture content, and the smaller the soil moisture content at the same location in the wetted body. With the increase of sediment concentration in muddy water, vertical migration distance of the wetting front decreased gradually. The sediment concentration had a significant effect on the moisture content distribution in the wetted body. All the isoline of moisture content distribution in the wetted body were nearly in the shape of a quarter ellipse, and moisture content distribution in the wetted body was closely related to the movement of water in the soil, and the isoline of moisture content distribution became denser with the increased of the distance away from the center of the film hole. The contents of NO-3-N and NH4+-N in wetted soil decreased with the increase of sediment concentration in muddy water. NO-3-N mainly distributed in the range of the wetting radius 10 cm, i.e., soil NO-3-N mainly distributed in shallow soil, which was conducive to the absorption and utilization of crop roots. The horizontal direction of the wetted body and the vertical direction of the film hole decreased with the increased of the distance from the center of the membrane hole, while the NH4+-N mainly distributed in the range of the wetting radius 5 cm, and the radius of the wetted body 5-10 cm. The content of NH4+-N decreased with the increase of soil depth. The conclusion of this study could provide a theoretical basis and technical support for further study on the infiltration of muddy water film hole irrigation.
