Alternative TitleResearch on soil moisture and evapotranspiration of different grasslands in the source region of Three Rivers
Thesis Advisor张耀生
Degree Grantor中国科学院西北高原生物研究所
Place of Conferral西北高原生物研究所
Keyword三江源 草地 土壤水分 蒸散 气象因子
Abstract三江源地处青藏高原腹地,环境条件十分严酷,水资源短缺和利用困难是制约该区植被恢复及生态重建的主要限制因子。近年来由于受气候暖干化和过度放牧等因素的综合影响,天然植被退化严重,区域水土流失加剧,生态环境问题日益突出,因此开展与植被建设紧密相关的草地生态水文学研究变得十分迫切。 本研究于2007年在三江源区域进行了相关研究,主要致力于以下三个方面的研究:1、不同类型草地土壤水分的时空动态比较分析;2、不同类型草地蒸散量动态及计测方法的研究;3、主要气象因子对土壤水分动态变化的影响。以期为该地区退化植被的恢复与生态环境综合治理提供科学依据。主要研究结果如下: 1、在植物生长季,不同类型草地土壤含水量的差异显著(P<0.05)(除高寒草甸和高寒草原外),但其动态变化规律基本一致。土壤水分的季节动态均可划分为积累期、消耗期和稳定期三个时段。不同草地土壤水分垂直变化与土层深度的关系不完全一致,但其剖面变化均可分为活跃层、调节层和相对稳定层三个层次。 2、对参考作物蒸散量计测方法相关分析表明:FAO P-M公式与P-48公式之间相关性较高,相关系数均在0.926以上;t测验表明温性草原和人工草地利用F-79公式计算的结果与FAO P-M结果的差异不显著,可用F-79修正式估算三江源温性草原和人工草地参考作物蒸散量。利用FAO-56和FAO P-M模型计算了四种类型草地群落的实际蒸散量,结果表明其动态变化过程具有相似性,蒸散强度均在8月中旬达到年度最高值,其中以人工草地最大,为2.408mm/d,而高寒草甸最小,为1.570mm/d。 3、土壤水分的动态主要受降水量及其季节分配的影响,并建立了降水量对土壤含水量的回归方程。实际蒸散量对0~20cm土层水分含量影响显著(P<0.05),而愈向土壤深层,影响愈不明显。土壤含水量对空气温度、空气相对湿度和风速的响应由土壤表层至深层均呈递减趋势。
Other AbstractThe source region of Three Rivers is located in the Qinghai-Tibetan plateau, and soil water deficits is the main limit factors of vegetation restoration and ecology reconstruction in this region. In recent years, the ecological problem stands out by grassland degradation and soil erosion as a result of climate warm-drying and overgrazing. So it is important to carry out the research of eco-hydrology in this region. In order to provide some suggestion for restoration of degrade vegetation of this region, the three questions were answered in this research in 2007. 1. temporal-spacial dynamic of soil moisture of different grasslands, 2. research on evapotranspiration of different grasslands, 3. effects of main weather factors on dynamic change of soil moisture. Main results were as follows: 1.In growth season, there were significant difference (P<0.05) in soil moisture among different grasslands except for alpine meadow and alpine pastureland , but the season dynamic of soil moisture of different vegetation types was almost similar, and it can be divided into three stages: accumulating stage, consumptive stage, stable stage. The relation of vertical change of soil water and soil depth was not uniform absolutely in four kinds of vegetation types. The vertical change of soil moisture can be classified three layers: active layer, regulative layer and relatively stable layer. 2.The ana1ysis results showed that the FAO Penman 1979 was all correlated well with the FAO Penman—Monteith. And the FAO Penman 1979 had a good agreement with FAO Penman-Monteith estimates in warm steppe and artificial grassland.The actual evapotranspiration of four type grasslands was calculated based on FAO-56 and FAO P-M model, and the result showed that the dynamic of the actual evapotranspiration was similar among different grasslands. It reached the peak value in the middle of the August; and the value (2.408mm/d) of artificial grassland was the highest, and alpine meadow was the lowest (1.570mm/d). 3.The dynamic of soil moisture was affected by precipitation and its seasonal distributed, and the regression equation of precipitation and soil moisture was set up. The correlation between actual evapotranspiration and soil moisture in 0~20 cm soil layer was significant (P<0.05), but the coefficient of correlation between evapotranspiration and the other deeper soil layers was lesser. Air temperature, air relative humidity and wind speed exert influences on soil moisture, and the responses of soil moisture to these factors were descending along soil layer depth.
Document Type学位论文
Recommended Citation
GB/T 7714
赵双喜. 三江源区主要类型草地土壤水分与蒸散研究[D]. 西北高原生物研究所. 中国科学院西北高原生物研究所,2008.
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