膜下滴灌微区环境对土壤水盐运移的影响

Micro drip irrigation district environmental impact on soil water and salt transport

  • 摘要: 基于膜下滴灌特有的"膜中"、"膜间"、"膜边"、"膜外"微区环境,利用2011—2013年田间对比试验方法获取的5 960个数据,运用柯布-道格拉斯模型,构建膜下滴灌环境土壤层次、灌水定额、土壤水分、气温、蒸发综合因素与土壤水盐关系及影响效应分析模型.结果表明,在气候干旱、蒸发强烈灌区,地膜覆盖与滴灌结合的地表介面灌溉形式下,土壤水盐具有水平方向由"膜中"向"膜边"地表裸露区定向迁移,垂直方向土壤水盐则由下向上层运移且趋于"膜外"边界积累的趋势,尤其是气温与蒸发因素交互作用,推进膜下滴灌土壤水盐在地膜覆盖与土壤裸露区域空间运移,研究结果进一步揭示了膜下滴灌"土壤水盐定向迁移"形成机理,为膜下滴灌土壤水盐地表排放模式应用提供了依据.

     

    Abstract: Drip irrigation under mulch is an efficient and water-saving irrigation practice implemented in the arid agricultural areas of China. Based on the micro environments specific to drip irrigation, i.e. "middle of the film", "between the film", "edge of the film" and "outside the film", as well as the 5 960 data collected during 2011—2013 by field contrast test, the relationships between soil level environment, irrigation quota, soil moisture, temperature, evaporation and water-salt movement were established through the Cobb-Douglas model. The results showed that, in arid irrigation areas with strong evaporation and under the combination of plastic film mulching and drip irrigation, soil water and salt migrate horizontally from the "middle of the film" towards the exposed "edge of the film", and vertically from the lower to the upper soil layers, tending to accumulate in the boundary at the "edge of the film". The interaction between temperature and evaporation, especially, drives the movement of soil water and salt at mulching spaces and in bare soils. The research further revealed the directional migration of soil water and salt in the context of drip irrigation under mulch, and can provide a basis for the application of water-salt surface discharge method in soils.

     

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