| 摘要: |
| 【目的】土壤持水特性是重要的土壤物理参数，低吸力段的土壤水分随土壤水吸力的变化而有比较显著的变化，测量方法决定了数据的可比性和测量周期。【方法】研究采用了常见的三种测量低吸力段土壤持水特性的仪器，包括：沙箱、压力板仪和HYPROP系统。对不同侵蚀程度黑土的持水特性进行了测定。【结果】结果显示：在pF1.5及以下，沙箱法的测量结果高于压力板仪法的测量结果；在pF1.8及以上沙箱法与压力板仪测量结果相似。HYPROP蒸发法测定的数据始终低于沙箱-压力板仪联合测定的结果。在pF1.0以下，差异极显著，在pF0.0时，二者测得土壤含水率差值为3.55%；在pF1.0时，二者的差异平均为1.20%。在pF1.0以上，平均为0.5%-1.26%，随着吸力值增加，二者差异有减少趋势。但对不同侵蚀程度的土壤，情况有所不同。容重大、质地轻的剧烈侵蚀土壤，两种方法测的结果的差异较少；容重小、质地重的土壤，两者差异大。【结论】因此，使用HYPROP法测定容重小、质地重土壤的低吸力段水分特征曲线时，可能需要使用沙箱法测定pF1.0以下的数据代替蒸发法测得的数据。但HYPROP法测试周期短、测量的吸力范围较沙箱法广，非常适合少量样品的快速测定。 |
| 关键词: 土壤持水特性；沙箱法；压力板仪法；HYPROP蒸发法 |
| DOI： |
| 分类号:S152.7+1 |
| 基金项目:国家重点研发计划项目 |
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| Comparison of Measuring Methods for Soil Water Holding Characteristics in Low Suction Stage |
|
Gao Xiaofei
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Faculty of Geographical Science, Beijing Normal University
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| Abstract: |
| 【Background】Soil water holding properties are important soil physical parameters. 【Objective】The soil moisture changes significantly with the change of soil water suction in the low suction stage. The measurement method determines the comparability of the data and the measurement time consuming. 【Method】Three common instruments were used to measure the soil water holding characteristics in the low suction stage, including: sand box, pressure plate apparatus and HYPROP system. The water-holding properties of black soils with different degrees of erosion were measured. 【Result】The results show that the measurement results of the sand box method are higher than that of the pressure plate apparatus at pF1.5 and below; the measurement results of the sand box method and the pressure plate instrument are similar at pF1.8 and above. The data measured by the HYPROP evaporation method are always lower than the results of the combined sand box-pressure plate apparatus. Below pF1.0, the differences are extremely significant. At pF0.0, the average difference in soil moisture content measured between the two methods is 3.55%; at pF1.0, the difference between the two is 1.20% on average. Above pF1.0, the average is 0.5%-1.26%. As the suction value increases, the difference between the two tends to decrease. However, the situation is different for soils with different degrees of erosion. For severely eroded soils with large bulk and light texture, the results of the two methods are less different; for soils with small bulk density and heavy texture, there is a big difference between the two.【Conclusion】Therefore, when using the HYPROP method to determine the water characteristic curve of the low suction stage of the soil with low bulk density and heavy texture, it may be necessary to use the sand box method to measure the data below pF1.0 instead of the data measured by the evaporation method. However, the HYPROP method has a shorter test cycle and a wider range of suction than the sand box method, which is very suitable for rapid determination of a small amount of samples. |
| Key words: Soil water retention characteristics; sand box method; pressure plate method; HYPROP evaporation method |
