Abstract The soil water was stratified sampling and analyzed with 0–100 cm by three plantation (Leucaena Benth Forest land, Dodonaea angustifolia Shrub land and Heteropogon contortus grassland) at the dry-hot Valley in Jinsha River, at June, September, December of 2016, which were to know about the variation and mechanism of soil water movement. The results showed that (1) soil water in different soil layers is significantly different, and the overall performance is shrub land (11.65%) > grassland (8.29%) > forest land (6.76%); (2) the δD isotope ratio of the soil water from all samples ranged from −146.359% to −54.628% and the δ18O isotope ratio ranged from −20.272% to −2.148%, and there is a good linear relationship between isotope ratios of soil water of three different soils; (3) there is a change with season: the intercept of the isotopes ratio at different months decreased in turn, June < September < December. While the shrub lands and grassland had the same pattern but slightly different, the isotope ratio of soil moisture in December was lower, and the intercepts of shrub land in September were significantly larger than in December; (4) there is a change in space: the total difference isotopes ratio of soil water is larger at the shallow soil layer and changed sharply at all positions of the forestland, while those in the shrub land and grassland changed became relatively weakly. This study provides the theoretical basis for the key problems of plant water using mechanism, ecological water demand, vegetation recovery and so on.

中文翻译：

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金沙江干热河谷不同土层干湿季氢氧同位素比表征土壤水分

摘要 2016年6月、9月、12月在金沙江干热河谷三个人工林（银合欢林地、金银花灌丛地和马齿苋草地）对土壤水分进行分层取样分析，范围为0~100 cm。 ，了解土壤水分运动的变化及其机理。结果表明：（1）不同土层土壤水分差异显着，总体表现为灌丛地（11.65%）>草地（8.29%）>林地（6.76%）；(2) 各样品土壤水的δD同位素比为-146.359%~-54.628%，δ18O同位素比为-20.272%~-2.148%，土壤同位素比之间存在良好的线性关系三种不同土壤的水；(3)随季节变化：不同月份同位素比截距依次减小，6月<9月<12月。灌丛地与草地格局相同但略有不同，12月土壤水分同位素比值较低，灌丛地9月截获量明显大于12月；(4)存在空间变化：浅土层土壤水分总差异同位素比值较大，林地各位置变化剧烈，而灌丛地和草地变化相对较弱。该研究为植物水分利用机制、生态需水量、植被恢复等关键问题提供了理论依据。灌丛地与草地格局相同但略有不同，12月土壤水分同位素比值较低，灌丛地9月截获量明显大于12月；(4)存在空间变化：浅土层土壤水分总差异同位素比值较大，林地各位置变化剧烈，而灌丛地和草地变化相对较弱。该研究为植物水分利用机制、生态需水量、植被恢复等关键问题提供了理论依据。灌丛地与草地格局相同但略有不同，12月土壤水分同位素比值较低，灌丛地9月截获量明显大于12月；(4)存在空间变化：浅土层土壤水分总差异同位素比值较大，林地各位置变化剧烈，而灌丛地和草地变化相对较弱。该研究为植物水分利用机制、生态需水量、植被恢复等关键问题提供了理论依据。浅土层土壤水的总差异同位素比值较大，在林地各位置变化剧烈，而灌丛地和草地变化相对较弱。该研究为植物水分利用机制、生态需水量、植被恢复等关键问题提供了理论依据。浅土层土壤水的总差异同位素比值较大，在林地各位置变化剧烈，而灌丛地和草地变化相对较弱。该研究为植物水分利用机制、生态需水量、植被恢复等关键问题提供了理论依据。