| 引用本文: | 陈文娟,李明思,李清林,等.覆膜滴灌条件下的土壤盐分表聚特征研究[J].灌溉排水学报,2022,41(9):93-100. |
| CHEN Wenjuan,LI Mingsi,LI Qinglin,et al.覆膜滴灌条件下的土壤盐分表聚特征研究[J].灌溉排水学报,2022,41(9):93-100. |
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| 摘要: |
| 【目的】探究新疆地区覆膜滴灌农田膜外土壤盐分表聚特征。【方法】以沙土和壤土为研究对象，通过室内试验，对2种质地的土壤分别进行了高蒸发强度和低蒸发强度处理，观测了覆膜滴灌条件下土壤盐分的水平分布和垂直分布；不同温度处理下，对2种质地的土壤进行了盐分表聚发展过程试验。【结果】覆膜滴灌条件下，2种土质的表层含盐量随距滴头水平距离呈指数函数分布；膜外土壤垂直剖面上的含盐量呈“Γ”型分布，盐分主要聚集在表层土壤中。其中，高蒸发强度处理下，沙土表层（0~2 cm）的平均含盐量是2 cm以下土层平均含盐量的7.3倍，壤土表层（0~2 cm）的平均含盐量是2 cm以下土层平均含盐量的8.4倍；低蒸发强度处理下，沙土和壤土的对应数值分别是7.2倍和7.9倍。影响土壤盐分表聚的主要因素是土壤水分的蒸发速率；土壤含水率、环境温度和蒸发强度的提高都可以增大土壤水分蒸发速率，导致土壤表面盐分聚集量增加，其中，土壤含水率所起的作用最大。土壤水分对盐分的溶解度随含水率的降低而下降，导致蒸发过程中盐分表聚速率存在峰值，而且峰值基本与环境温度正相关。【结论】土壤水分汽化散失使盐分从溶液中离析是导致土壤盐分表聚的本质；蒸发作用下，壤土的盐分表聚速率比沙土的盐分表聚速率高。 |
| 关键词: 覆膜滴灌；土质；盐分表聚；聚集速率 |
| DOI：10.13522/j.cnki.ggps.2021389 |
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| Salt Accumulation and Distribution under Mulched Drip Irrigation |
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CHEN Wenjuan, LI Mingsi, LI Qinglin, LI Dongwei
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1. College of Sciences, Shihezi University, Shihezi 832000, China;
2. College of Water Conservancy and Architectural Engineering,Shihezi University, Shihezi 832000, China
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| Abstract: |
| 【Background and objective】Mulched drip irrigation can push salt out of the root zone to sustain crop growth, but evaporation from soil outside the mulching film drives the salt to redistribute. Understanding salt accumulation and redistribution under mulched drip irrigation is important to alleviate soil salinization. Taking Xinjiang as an example, the objective of this paper is to experimentally study salt accumulation and redistribution in soil under mulched drip irrigation.【Method】 The experiment was conducted in a laboratory using repacked sandy soil and loamy soil. For each soil, we compared high evaporation and low evaporation both adjusted by temperature. Salt distribution in the horizontal and vertical directions was measured in each treatment. 【Result】 Regardless of soil type, salt content in the soil surface decreases exponentially along the distance away from the emitter. In the vertical direction, salt content in the soil outside the mulching film is distributed in a “Γ” type, and the salt mainly accumulates in the soil proximal to the surface. Under high evaporation, the average salt content in the surface (0~2 cm) of the sandy soil is 7.3 times that in the subsoil below the depth of 2 cm, while the average salt content in the surface (0~2 cm) of the loamy soil is 8.4 times that in the subsoil below the depth of 2 cm. At low evaporation, the associated salt content in the surface of the sandy and loamy soils is 7.2 times and 7.9 times, respectively, that in the subsoils. Soil evaporation is the main determinant of salt accumulation in the soil surface. Increasing soil moisture content, temperature or evaporation enhances evaporation, leading to an increase in salt accumulation in the soil surface. Because salt solubility drops when soil water content decreases, there is a peak in salt accumulation rate during the evaporation process, which is positively correlated with temperature. 【Conclusion】The evaporation of soil water leads to salt precipitation around the soil surface. Salt accumulation at the loamy soil surface is higher than that at the sandy soil surface. These results can help design mulched drip irrigation for crops in salt-affected soils. |
| Key words: mulched drip irrigation; soil texture; salt accumulation; accumulate rate |
