沙地小叶杨和柠条细根分布与土壤水分消耗的关系

Relationship between fine roots distribution and soil water consumption of Populus simonii and Caragana korshinkii plantation on sandy land

以生长在陕北水蚀风蚀交错带沙地上的人工小叶杨（Populus simonii）和柠条（Caragana korshinkii）为研究对象，采用剖面法调查2个树种的细根分布特征，通过2年土壤水分定位观测研究，初步分析沙地小叶杨和柠条细根分布与土壤水分消耗的关系。结果表明：1）沙地小叶杨和柠条随土层深度增加，细根表面积密度逐渐减小，0～100cm土层分别集中了整个剖面细根总量的63％和95％；2）小叶杨和柠条林地剖面土壤水分与细根垂直分布密切相关，小叶杨和柠条林地土壤水分特征类似，可分为3个层次：0～50cm土层为速变层，50～200cm土层为缓变层，200cm以下土层为缓慢衰减层；3）2年观测期内，小叶杨和柠条林地总蒸散量接近，与同期降水量基本持平，而裸沙地土壤储水量增加；4）小叶杨和柠条细根趋于浅表化的分布特征是对沙地浅层土壤经常获得雨水补给适应的结果。研究结果可为水蚀风蚀交错带沙区防护林建设提供理论依据。

The relationship between fine roots distribution of Populus simonii and Caragana korshinkii and soil water in the wind-water erosion crisscross region of the Loess Plateau were studied based on 2-year field positioning observation. The following conclusions can be drawn from this paper： 1 ） The fine root area density profile was similar between Populus sirnonii and Caragana korshinkii stands. According to the soil water variation, the soil profile can be divided into 3 layers： 0 - 50 cm was fast change layer, 50 - 200 cm was slow change layer and gradually attenuation layer below 200 cm. 3） Total ET in Populus simonii stand was close to Caragana korshinkii stand during 2-year, and which almost equaled to rainfall during the same period. 4） Most of fine roots of Populus simonii and Caragana the upper soil was frequently recharged by rainfall korshinkii concentrated in shallow layer of soil, because in this region. These results will provide an importanttheoretical basis to protection forest construction in the wind-water erosion crisscross region.