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    杨爱国, 付志祥, 王玲莉, 肖凤祥, 王利, 范鹏辉, 张建秋. 科尔沁沙地杨树水分利用策略[J]. 北京林业大学学报, 2018, 40(5): 63-72. DOI: 10.13332/j.1000-1522.20170430
    引用本文: 杨爱国, 付志祥, 王玲莉, 肖凤祥, 王利, 范鹏辉, 张建秋. 科尔沁沙地杨树水分利用策略[J]. 北京林业大学学报, 2018, 40(5): 63-72. DOI: 10.13332/j.1000-1522.20170430
    Yang Aiguo, Fu Zhixiang, Wang Lingli, Xiao Fengxiang, Wang Li, Fan Penghui, Zhang Jianqiu. Strategies on water utilization of poplar in Horqin Sandy Land of northern China[J]. Journal of Beijing Forestry University, 2018, 40(5): 63-72. DOI: 10.13332/j.1000-1522.20170430
    Citation: Yang Aiguo, Fu Zhixiang, Wang Lingli, Xiao Fengxiang, Wang Li, Fan Penghui, Zhang Jianqiu. Strategies on water utilization of poplar in Horqin Sandy Land of northern China[J]. Journal of Beijing Forestry University, 2018, 40(5): 63-72. DOI: 10.13332/j.1000-1522.20170430

    科尔沁沙地杨树水分利用策略

    Strategies on water utilization of poplar in Horqin Sandy Land of northern China

    • 摘要:
      目的在科尔沁沙区, 杨树人工林出现了不同程度的退化现象, 水分是本地区植物生存的主要限制因子, 本文为了探究科尔沁沙地杨树人工林的水分来源及水分利用机制, 揭示水分与杨树人工林退化的关系, 为科尔沁沙地杨树人工林生态系统恢复和重建提供参考依据。
      方法利用氧稳定同位素技术以科尔沁沙地杨树人工林为研究对象, 采用“DELTA plus XP”稳定同位素比例质谱仪测定植物(木质部)水及各潜在水源δ18O值, 结合自动气象站(HOBO U30-NRC)连续观测降雨量等环境和气象因子, 利用同位素质量守恒多元分析方法, 分析雨季和旱季杨树人工林水分利用策略。
      结果(1) 雨季土壤含水量均高于旱季, 雨季在0~100 cm土层的土壤含水量随土层深度显著增加(P < 0.05), 而100~170cm土层的土壤水分含量显著下降(P < 0.05);旱季林内土壤水分含量均大于林外土壤水分含量, 但差异均不显著(P>0.05)。(2)土壤水和植物水δ18O值都高于地下水δ18O值; 旱季土壤水δ18O值整体上比植物水δ18O值低; 雨季土壤水δ18O值反而高于植物水δ18O值。(3)杨树人工林旱季主要吸收利用130cm以下的深层土壤水, 对浅层土壤水利用较少; 雨季杨树人工林除了吸收130cm以上土壤水, 还少量的吸收深层土壤水和地下水。
      结论(1) 浅层土壤水氧同位素值受到太阳辐射和降水的干扰程度较大, 而深层土壤水受到的干扰程度较小。在旱季, 林内各层土壤水均大于林外各层土壤水, 尤其是80~170cm土壤层更加显著, 这从侧面解释了杨树在利用较深的土壤水及地下水时, 会将少量水分释放到土壤表层这一现象。(2)雨季沙地杨树人工林主要利用浅层土壤水, 旱季杨树人工林主要利用深层土壤水和地下水。杨树人工林根系在浅层和深层土壤中均有分布, 此种根系分布特征保证了杨树人工林在不同季节采用不同的水分利用策略, 从而确保自身水分的生理需要, 是植物应对干旱沙地环境适应性的表现。

       

      Abstract:
      ObjectiveIn Horqin Sandy area of northern China, the poplar plantations have shown different degree of degradation, and water is the main limiting factor to plant survival in this region. This study aims to explore the mechanism of water source and utilization, reveal the relationship between moisture and poplar plantation degradation, in order to provide the reference basis for the ecosystem restoration and reconstruction of poplar plantation in Horqin Sandy Land.
      MethodIn this study, the poplar plantation(Populus simonii|×Populus nigra) in Horqin Sandy Land was studied by isotope technique, and the stable δ18O isotope value of poplar stem and xylem was measured using the "delta plus XP" stable isotope ratio mass spectrometry, combined with the automatic weather station (HOBO U30-NRC) for continuous observation of rainfall and meteorological environment factor, analysis of water use strategy of poplar plantation in rainy season and dry season by isotope mass conservation.
      Result(1) The soil moisture of rainy season was higher than that of dry season. The soil moisture of 0-100cm soil layer in rainy season increased significantly with soil depth (P < 0.05), while the soil water content of 100-170cm soil layer decreased significantly (P < 0.05). In the dry season, the soil moisture content in the forest was higher than outside the forest, but the difference was not significant (P> 0.05). (2) The δ18O values of soil water and tree plant water were both higher than the δ18O values of groundwater. The δ18O values of soil water in dry season were lower than δ18O values of tree branch xylem, while the δ18O values of soil water in rainy season were higher than δ18O values of tree branch xylem. (3) In the dry season, poplar plantations mainly absorbed soil water and groundwater below 130 cm soil, and also had a small amount of absorption in shallow soil water. In the rainy season, apart from absorbing soil water above 130cm, the poplar plantation also absorbed a small amount soil water and groundwater from deep soil.
      Conclusion(1) The solar radiation and rainfall have great inference on oxygen isotopes of shallow soil water, but little interference on deep soil water. In dry season, the soil moisture content in the forest was higher than outside the forest, especially in 80-170cm soil layer was more significant. It explained the phenomenon from the side aspect that poplar will release small amount water to the surface soil when utilizing the deep soil water and groundwater. (2) Poplar plantation in Horqin Sandy Land mainly use shallow soil water during the rainy season, but mainly use deep soil water and groundwater during the dry season. The root system of poplar plantations in Horqin Sandy Land distributed in both shallow and deep soils, the distribution of this root system ensured that poplar plantation adopted different water use strategies in the dry and rainy seasons, thus to ensure its own moisture. This manifestation is the adaptability of plants to the arid sand environment.

       

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