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| DOI：10.13522/j.cnki.ggps.2017.0713 |
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| Water Retention Curve of Vegetative Soils in Erhai Lake |
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CHEN Anqiang， LEI Baokun， HU Wanli， MAO Yanting， YANG Yanxian， FU Bin， ZHANG Dan
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1. Agricultural Environment & Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming 650201, China; 2.College of Resources and Environment, Yunnan Agricultural University, Kunming 650201, China
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| Abstract: |
| 【Objective】 Water retention curve is one of the most important parameter to quantify movement and bioavailability of water in soil and in this paper we measured and compared the water release curve of vegetative soils in Erhai lake catchment as well as the factors affecting it. 【Method】 Soil samples at different locations and depths were taken based on soil genesis, and their water retention curves were measured using the pressure-membrane apparatus. For each measured curve, we fitted it to the van Genuchten model. 【Result】 Soil moisture content decreased as soil matric potential increased, and all measured water characteristic curves can be fairly well by the van Genuchten model. Saturated water content, the residual water content and the parameter n in the model increased with the silt and clay content, the organic matter and soil porosity, but decreased as the sand content and bulk density increased, as opposed to the parameter a in the model. Soil organic matter, sand and clay contents were the key factors that affected the shape of the soil water characteristic curve. Soil at different depths were divided into three categories based on the above factors. Category 1 consisted of the plough horizon, and Category 2 consisted of the pan horizon and parent-material horizon and the hydrogric horizon; the remaining was in Category 3. 【Conclusion】 The deep soil layer and the soil in proximity of the Erhai Lake shore have the lowest water holding capacity and are thus easy for water and solute to move through. The ability of the Gley horizon, the illuvium and parent maternal horizons to hold water increases with elevation, but the long-term cultivation alertes the ability in the plough layer and the pan horizon to hold water, rendering them independent of elevation. |
| Key words: soil water characteristic curve; aerated zone soil; redundancy analysis; Erhai Lake; nearshore vegetable filed |
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