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    宽垄沟灌肥液入渗水氮运移特性分析及数值模拟

    Analysis and Numerical Simulation of Water and Nitrogen Transport Characteristics of Fertilizer Solution Infiltration in Wide Ridge and Furrow

    • 摘要: 为研究宽垄沟灌肥液(硝酸铵)入渗过程中水氮运移特性,利用HYDRUS-2D模型对不同肥液浓度条件下土壤水力特性参数和溶质运移参数进行数值反演,模拟不同含水率、肥液浓度条件下的水氮运移.结果表明:运用数值反演方法得出的参数具有较高的准确性,可以使用HYDRUS-2D模型模拟沟灌水氮运移;硝态氮易随水分运动、铵态氮更易被土壤吸附;累积入渗量、湿润锋运移距离在肥液浓度为600mg·L-1时相较于300mg·L-1时分别增加了7.51%和3.98%,在肥液浓度为900mg·L-1时相较于300mg·L-1时分别增加了14.36%和9.6%;硝态氮、铵态氮质量分数在肥液浓度为600mg·L-1时相较于300mg·L-1时分别增加了101.6%和84.62%,在肥液浓度为900mg·L-1时相较于300mg·L-1时分别增加了224.7%和176.71%;土壤中硝态氮、铵态氮经过5d再分布后,浅层土壤中的硝态氮、铵态氮质量分数呈递减趋势,铵态氮的硝化速率低于硝态氮随水分向深层土壤运移的速率.

       

      Abstract: To study the water and nitrogen transport characteristics during the infiltration process of fertilizer solution(ammonium nitrate) in wide furrows,the HYDRUS-2D model was used in laboratory experiments.The soil hydraulic characteristics parameters and solute transport parameters were derived by the numerical inversion method under different fertilizer concentrations.The water and nitrogen transports under different water contents and fertilizer concentrations were simulated.The results showed that the parameters obtained by the numerical inversion method were very accurate,and the HYDRUS-2D model was able to simulate nitrogen transport in furrow irrigation.Nitrate nitrogen was more likely to move with water,and ammonium nitrogen was more easily adsorbed by soil.The cumulative infiltration and wetting front migration distance under the condition of 600mg·L-1 fertilizer concentration increased by 7.51% and 3.98%,respectively,compared with 300mg·L-1 fertilizer concentration; and the cumulative infiltration and wetting front migration distance under the condition of 900mg·L-1 fertilizer concentration increased by 14.36% and 9.6%,respectively,compared with 300mg·L-1 fertilizer concentration.The content of nitrate nitrogen and ammonium nitrogen under the condition of 600mg·L-1 fertilizer concentration increased by 101.6% and 84.62%,respectively,compared with 300mg·L-1 fertilizer concentration; and the content of nitrate nitrogen and ammonium nitrogen under the condition of 900mg·L-1 fertilizer concentration increased by 224.7% and 176.71%,respectively,compared with 300mg·L-1 fertilizer concentration.The nitrate nitrogen and ammonium nitrogen in soil were redistributed after 5 days:the content of nitrate nitrogen and ammonium nitrogen in shallow soil decreased gradually,and the nitrification rate of ammonium nitrogen was lower than the rate of nitrate nitrogen moving to deep soil with water.

       

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