Non-uniform distribution of soil salinity along a transect of an irrigation field in an arid region.
Non-uniform distribution of soil salinity along a transect of an irrigation field in an arid region.
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发表时间：
2015
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通讯作者：
T. Kume;T. Yamamoto;K. Shimizu;A. Jalaldin
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作者：
T. Kume;T. Yamamoto;K. Shimizu;A. Jalaldin
我们在田间尺度上评估了土壤盐分，并为干旱地区提出了适当的水盐管理措施。具体而言，我们专注于非均匀盐度分布沿着样带在一个研究领域。我们还研究了影响盐分分布的因素，包括灌溉、排水和盐分运动。田间盐分分布的不均匀性可能与灌溉管理和距主要排水渠道的距离有关，而土壤物理性质和地下水的影响有限。在过去的灌溉时期，当大量的坎儿井水可用于淋洗灌溉时，主要排水渠道功能良好，这导致了目前的盐分分布不均匀。目前，农民使用较少的灌溉水，这并没有促进脱盐。近地表可溶性盐分的垂直运移主要受灌溉管理的影响。畦灌促进了海水淡化，而滴灌促进了盐分积累，由于极端干旱气候下蒸发率高，灌溉后盐分增加。根据这些结果，我们用非技术性语言向当地农民解释了以下几点：1）排水渠道对于脱盐很重要，但目前的渠道不再足以从田间排出盐分; 2）滴灌对于亏缺灌溉是有效的，但它会增加盐分的积累; 3）畦灌对土壤表层盐分淋溶有积极作用，但停止灌水后，淋溶出的盐分又返回到表层;（4）60 cm以下土层存在高盐层，分布广泛。
We assessed soil salinity at field scale and suggested appropriate water and salt management practices for an arid region. Specifically, we focused on non-uniform salinity distribution along a transect in a research field. We also examined factors affecting the distribution of salt, including irrigation, drainage and salt movement. The non-uniform salinity distribution across the field was probably formed by irrigation management and distance from main drainage channel, while the effect of soil physical properties and groundwater was limited. The main drainage channel functioned well during the past irrigation period when abundant Karez water was available for leaching irrigation, and this contributed to the present non-uniform salinity distribution. Currently, farmers use less irrigation water, which does not promote desalinization. Vertical movement of soluble salts near the soil surface was dominated by irrigation management. Border irrigation promotes desalinization but drip irrigation enhances salt accumulation, with salinity increasing after irrigation because of high evaporation rates in the hyperarid climate. Based on these results, we explained the following points to local farmers in non-technical language: 1) a drainage channel is important for desalinization but the current channel is no longer sufficient to discharge salt from the field; 2) drip irrigation is effective for deficit irrigation but it enhances salt accumulation; 3) border irrigation has a positive effect on salt leaching from surface layers but the leached salt returns to the surface after irrigation ceases; and 4) there are high salinity layers below 60 cm soil depth, distributed widely across the fields.