新疆膜下滴灌棉田暗管排盐的数值模拟与分析Ⅰ:模型与参数验证

发布时间：2018-05-11 19:36

本文选题：排盐 + 暗管　；参考：《水利学报》2016年04期

【摘要】：新疆地区广泛应用膜下滴灌技术进行棉花种植,易在膜下浅层根区(0~40 cm)形成淡化区域,而深部根系层(40~60 cm)却始终处于积盐状态,具有较大的积盐和返盐隐患。为了更为便捷地探索节水、高效的暗管排盐模式,在开展蓄水淋洗条件下暗管(埋深60 cm、间距500 cm)排水、排盐田间试验和分析建立相应数值模型的基础上,利用HYDRUS软件和田间试验数据对所建立的数值模型和水盐运动参数进行了校验,结果表明模拟值与实测值之间整体吻合较好,剖面土壤含水量分布的最大均方根差(RMSE)和最小决定系数(R2)分别为0.025 cm~3/cm~3和0.88,含盐量分布的最大RMSE和最小R2分别为2.74 g/kg和0.93,基本在可接受范围之内。尽管剖面土壤脱盐率可达77.5%,但绝大部分盐分都被淋洗至暗管以下土层,暗管排盐量十分有限,仅占60 cm以上土体盐分总量的11.7%,因此有必要探索膜下滴灌棉田暗管排盐的改进模式或方法,以有效提高其排盐效率。本文所建立的数值模型和相关水盐运动参数可以较好地描述暗管排水、排盐过程中的土壤水盐动态,并进一步用于当地膜下滴灌棉田不同暗管排盐模式的数值模拟与分析,从而为新疆膜下滴灌棉田高效排盐模式的探索提供科学依据。
[Abstract]:It is easy to form desalination area in cotton planted by drip irrigation under film in Xinjiang area, but 4060 cm in deep root layer is always in the state of salt accumulation, which has great potential of salt accumulation and salt return. In order to more conveniently explore the water-saving and high-efficiency salt discharge model of dark pipe, a numerical model was established on the basis of the drainage of dark pipe (60 cm buried depth, 500 cm spacing) under the condition of water storage and leaching, and the field test and analysis of salt discharge. By using HYDRUS software and field experiment data, the established numerical model and the parameters of water and salt movement are verified. The results show that the simulated values are in good agreement with the measured values. The maximum root mean square difference (RMSE) and minimum determination coefficient (R2) of soil water content distribution in the profile were 0.025 cm~3/cm~3 and 0.88, respectively, and the maximum RMSE and minimum R2 of salt content distribution were 2.74 g/kg and 0.93 respectively, which were basically within the acceptable range. Although the desalinization rate of the profile soil can reach 77.5%, most of the salt is washed into the soil layer below the submerged pipe, and the amount of salt discharged from the deep pipe is very limited. Only 11.7% of the total salt content of soil above 60 cm, therefore, it is necessary to explore the improved model or method of salt discharge in cotton field under film drip irrigation, in order to effectively improve the efficiency of salt discharge. The numerical model established in this paper and the related parameters of water and salt movement can better describe the soil water and salt dynamics in the process of drainage and discharge of salt in dark pipes, and further be used for the numerical simulation and analysis of different models of salt discharge in drip irrigation cotton fields under local film. Therefore, it provides scientific basis for the exploration of efficient salt discharge model of drip irrigation cotton field under mulch film in Xinjiang.
【作者单位】：中国农业大学水利与土木工程学院;中国农业大学资源与环境学院;以色列农业研究中心;
【基金】：国家自然科学基金项目(41171185,51321001) 公益性行业(农业)科研专项经费项目(200903001-03-02)
【分类号】：S156.4

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