| 摘要: |
| 【目的】研究红壤区涌泉根灌双点源入渗土壤水氮运移及转化分布规律，为提高涌泉根灌水氮利用效率和灌水器合理埋深提供理论依据。【方法】在大田通过灌水器埋深分别为30、45、60 cm的硝酸铵钙溶液入渗试验，通过大田肥液（什么肥具体）入渗试验，研究了灌水器埋深（具体，补充）对涌泉根灌双点源交汇入渗土壤的入渗能力、湿润锋运移距离、土壤水分以及铵态氮和硝态氮的运移特性的影响，并建立了红壤涌泉根灌土壤累计入渗量及湿润锋运移距离与入渗历时的关系模型。【结果】灌水器埋深分别为30、45和60 cm时，红壤累计入渗量和稳定入渗率分别为18.84 L和0.035 cm/min、17.09 L和0.031 cm/min以及14.37 L和0.024 cm/min，即灌水器埋深越大，土壤的累计入渗量和稳渗率就越小，且累计入渗量与入渗历时之间均符合幂函数关系；灌水器埋深分别为30、45和60 cm时，交汇入渗发生的时间分别为168、187和197 min，增幅依次为10.16%和5.56%，灌水器埋深越大，土壤湿润锋交汇时间就越晚，湿润锋运移距离随埋深的增大而减小，运移距离与入渗历时之间均符合对数函数关系，且竖直向下的运移距离均大于竖直向上；土壤含水率均随着土层深度的增加而先增加后减小，对于同一土层而言，灌水器处土壤含水率最大，其次为交汇面处，而距离灌水器12.5 cm处土壤含水率最小；土壤铵态氮和硝态氮均随土层深度的增加而先增加后减小，在水平方向，距离灌水器越近，铵态氮的质量浓度就大，而对于硝态氮而言，灌水器埋深不同，硝态氮的分布存在明显差异灌水器处浓度最大，其次为交汇面处，而距离灌水器12.5 cm处硝态氮的浓度最小。【结论】灌水器埋深对涌泉根灌双点源交汇入渗土壤红壤的水氮运移分布均有显著影响，且埋深超过60 cm时，氮肥氮素淋失风险较大，且对作物吸收不利。 |
| 关键词: 红壤;涌泉根灌;灌水器埋深;水氮运移 |
| DOI： |
| 分类号:S275 |
| 基金项目:江西省教育厅研究项目(GJJ180952)；江西省科技厅研究项目(20192BAB216037)；中国农科院水资源安全高效利用重点开发实验室开放(2019BB02) |
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| Effect of Emitter Depth on Water-nitrogen Transport in Duel-point Source Infiltration under Surge-root Irrigation in Red Soil Region |
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DAI Zhiguang1, CAI Yaohui2
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1.Nanchang Institute of Technology;2.Northwest A&F University
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| Abstract: |
| Red soil is mainly distributed in the hilly regions and is one of the important soil resources in China. The seasonal drought in the red soil region and the problems of acidity, stickiness and leanness severely restrict the development of local agriculture. Combined with the characteristics of red soil, it is of great significance to study the distribution of water and nitrogen transport of Surge-root irrigation (SRI) in red soil area.【Objective】 Studying the law of water and nitrogen transport and transformation in the duel-point source infiltration under SRI in the red soil area, which could provide the theoretical basis for improving the nitrogen utilization efficiency of SRI and the reasonable buried depth of the emitter under SRI.【Method】In the field, an infiltration experiment of calcium ammonium nitrate solution with 30, 45, and 60 cm burial depth of emitter was conducted to study the infiltration capacity, the soil infiltration capacity, wetting front migration, soil moisture, and the migration characteristics of ammonium nitrogen and nitrate nitrogen and the relationship model of cumulative soil infiltration volume and humid front migration distance with infiltration duration of SRI irrigation in red soil was established. 【Result】When the emitter depths were 30, 45 and 60 cm, the cumulative infiltration volume and stable infiltration rate of red soil were 18.84 L and 0.035 cm/min, 17.09 L and 0.031 cm/min and 14.37 L and 0.024 cm/min, respectively., which indicated the larger the emitter depths, the smaller the cumulative infiltration and stabilization rate of the soil, and the cumulative infiltration and the infiltration duration was in a power function relationship. When the emitter depths were 30, 45 and 60 cm, the time of intersection infiltration were 168, 187 and 197 min, respectively. The migration distance of the wet front decreased with the increase of emitter depth, and the migration distance and the infiltration duration were in a logarithmic function relationship, and the vertical downward migration distance was greater than the vertical upward. The soil moisture content (SWC) increased first and then decreased as the increase of soil layer depth. For the same soil layer, the SWC was the largest near the emitters, and the soil at a distance of 12.5 cm to the emitters was the smallest. The ammonium nitrogen and nitrate nitrogen increased first and then decreased as the depth of soil layer increased, in the horizontal direction, the closer to the emitter, the greater the concentration of ammonium nitrogen, and for nitrate nitrogen, the distribution of nitrate nitrogen was significantly different with the different emitter depths.【Conclusion】The emitter depths had significant effects on water-nitrogen transport characteristics for duel-point source intersection infiltration under SRI for red soil region, and when the emitter depth exceeds 60 cm, the risk of nitrogen leaching is greater, which not good for improving the water-nitrogen use efficiencies for crop.
Keywords：red soil; surge-root irrigation; emitter depths; water-nitrogen transport |
| Key words: red soil;surge-root irrigation;emitter depths;water-nitrogen transport |
