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题名	砂石覆盖对土壤入渗及蒸发的影响
学位类别	硕士
答辩日期	2009
授予单位	中国科学院研究生院
授予地点	陕西
导师	冯浩
学位专业	水土保持与荒漠化防治
中文摘要	在干旱半干旱地区，利用砂石覆盖土壤，不但可以减少土壤蒸发，同时也能使土壤表面免受雨滴的溅蚀，从而防止水土流失，是解决该区干旱缺水和水土流失问题的重要途径之一。本文通过室内试验研究了不同粒径和厚度砂石对土壤入渗和蒸发的影响，确定比较适宜的砂石厚度和粒径配比范围，为农业生产提供理论和技术依据。主要研究结论如下： （1）一定入渗历时的累积入渗量与砂石粒径的关系比较复杂。不论覆盖厚度大小， 中粒径砂石覆盖的累积入渗量最小，大粒径和小粒径砂石覆盖的相对较大。在8cm厚度处理中，小粒径砂石覆盖的累积入渗量比大粒径砂石的大；而在14cm厚度处理中，小粒径砂石覆盖的累积入渗量比大粒径砂石的小。 （2）不同粒径配比的砂石累积入渗量存在一定差异，但差异较小，特别是粗砂石和细砂石之间的差异比较小。不论砂石粒径多大，砂石厚度越大，累积入渗量越大。另外，砂石粒径越大，不同覆盖厚度处理之间的差异越大。与均匀土壤一样，有砂石覆盖的土壤的湿润锋深度随时间的关系遵从幂函数规律。砂石粒径和覆盖厚度对湿润锋的影响效果与累积入渗量基本一致。（3）蒸发试验研究结果表明，砂石覆盖能有效地抑制土壤蒸发，在土壤含水量较高的阶段，这种抑制作用更加明显。砂石覆盖对土壤蒸发的抑制作用与粒径和覆盖厚度密切相关，在2.5～40mm粒径范围内，随着砂石粒径的增大，砂石覆盖对蒸发的抑制作用降低，对蒸发过程的影响减弱，覆盖厚度越大，蒸发量越小。有效的砂石配比应选择细砂石处理，不宜过粗。（4）在40天的连续蒸发过程中，砂石覆盖条件下的蒸发速率基本恒定在0.50mm/d-1.01mm/d，其累积蒸发量与时间呈显著的线性关系，而对照处理的呈对数关系。不同粒径砂石的配比试验显示，细砂石和中砂石抑制蒸发的效果明显优于粗砂石。试验结束后测得覆盖土壤的各个深度土壤含水量均较对照高，且各个深度土壤含水量基本接近，无覆盖土壤3-12cm深度范围内土壤含水量随土壤深度增加而增加，12cm以下的土壤含水量基本一致。
英文摘要	In arid/semi-arid regions, gravel mulch can not only reduce soil evaporation, but also can prevent soil from eroding by water. It is important way to solve the drinking water problem and soil and water loss in some area of the deficiency of water resources. This paper presents the results of the laboratory simulating experiment conducted to evaluate the effect of two parameters of the mulch–grain size and thickness–on soil moisture evaporation and infiltration, define suitable thickness and grain size distributions of gravel mulch. All of that are the theory and technology values for agricultural production. The results obtained are described as follows:(1) The relation between cumulative infiltration and grain size is very complex within certain infiltration duration. Whatever gravel mulch thickness is, the fine and the coarse gravel tend to be higher compared to the medium gravel in terms of cumulative infiltration. In addition, the fine gravel tend to be higher compared to the coarse gravel in terms of cumulative infiltration in 8 cm thickness treatment, while the fine gravel tend to be lower compared to the coarse gravel. (2) There existed small differences among different mixing distribution gravel, cumulative infiltration of coarse gravel is biggest. Whatever grain size of gravel is, cumulative infiltration increases with the increase of gravel mulch thickness. In addition, the differences of cumulative infiltration among different thickness treatment increase with gravel size of gravel. Just as control, the relationship between cumulative infiltration from mulched soil surface and time can be described by the power function under gravel mulch. The effect of gravel thickness and grain size on wetting front is consistent with cumulative infiltration.(3) The results of evaporation experiment indicated gravel mulch can efficiently suppress soil moisture evaporation, especially at the high level of soil water content. Inhibitory effects of gravel mulch on the evaporation are negatively correlated with grain size and positively correlated with thickness within 2.5~40mm grain size. Fine gravel mulch is effective mixing gravel mulch.(4) The relationship between cumulative evaporation from mulched soil surface and time can be described by the linear function under gravel and sand mulching, but logarithm function under bare surface during the successive evaporation of 40 days. The mulched soils, irrespective of layer thickness and grain size, presented a constant evaporation rate about 0.50mm/d-1.01mm/d throughout the experiment. The fine and the medium gravel tend to be more effective compared to coarse in 11cm thick layer. Water content at all depths of the covered soils was higher than in the uncovered soils at the end of the experiment. In the former, water distribution in the profile was markedly uniform, whereas in the latter a increase in water content was seen from 3 cm to a depth of 12 cm, then remained somewhat uniform in water content below 12 cm.
公开日期	2011-07-01
内容类型	学位论文
源URL	[http://ir.iswc.ac.cn/handle/361005/4121]
专题	水土保持研究所_水保所知识产出(1956-2013)
推荐引用方式 GB/T 7714	. 砂石覆盖对土壤入渗及蒸发的影响[D]. 陕西. 中国科学院研究生院. 2009.

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