膜孔直径对浑水膜孔灌土壤水氮运移特性的影响

通过对西安粉壤土进行4种膜孔直径(6,8,10,12cm)的浑水膜孔肥液自由入渗室内试验,观测并分析了湿润锋运移距离、累积入渗量、湿润体内水分分布以及NO_3~--N和NH_4~+-N运移特性的变化规律。结果表明:膜孔直径对浑水膜孔灌土壤水氮运移特性具有较为显著的影响。不同膜孔直径的浑水膜孔灌肥液自由入渗累积入渗量符合Philip入渗模型;湿润锋运移距离与入渗时间呈极显著的幂函数关系;在相同的入渗时间内,膜孔直径越大,湿润锋运移距离越大,单位膜孔面积累积入渗量越小,同一位置处土壤NO_3~--N和NH_4~+-N含量越大。入渗400min内,在膜孔中心附近区域NO_3~--N和NH_4~+-N含量较高,湿润体内土壤NO_3~--N主要集中分布在距膜孔中心15cm范围内,而NH_4~+-N主要集中分布在距膜孔中心8cm范围内。

Effect of Film Hole Diameter on Transport Characteristics of Water and Nitrogen in Soil Under Film Hole Irrigation with Muddy Water

The experiments of fertilizer infiltration through muddy water film hole with four diameters (6, 8, 10 and 12 cm) were carried out in lab using Xi''an silty loam soil. Migration distance of the wetting front, cumulative infiltration, soil water distribution in the wetted body and transport characteristics of and were observed and analyzed. The results showed that:The film hole diameter had a significant effect on transport characteristics of water and nitrogen under the muddy water film hole irrigation. The cumulative infiltration amount of fertilizer through muddy water film hole with different diameters conformed to Philip infiltration model. There was a significant power function relationship between migration distance of the wetting front and infiltration duration. Within the same infiltration time, cumulative infiltration volume of per unit area gradually decreased with the increasing of film hole diameter, while migration distance of the wetting front and contents of NO^-₃-N and NH⁺₄-N in the same position increased with the increasing of film hole diameter. Content NO^-₃-N and NH⁺₄-N were both higher in the center of the film hole within 400 minutes of infiltration. The soil NO^-₃-N in the wetted body was mainly distributed in the range of 15 cm from the center of the film hole, and NH⁺₄-N in the wetted body was mainly distributed in the range of 8 cm from the center of the film hole.