Subjects: Biology >> Ecology submitted time 2023-05-17 Cooperative journals: 《干旱区地理》
Abstract： In order to explore the influence of microtopography on the natural regeneration of Picea crassifolia seedlings in Qilian Mountains, Picea crassifolia forest was selected as the research object, and the topographic parameters (altitude, convexity and slope) of 15 fixed plots in the watershed were divided into four different microtopographic habitats by C-mean fuzzy clustering, and the effects of microtopographic habitats on the renewal characteristics (renewal seedling density, average crown width, mean base diameter and average plant height) of the regeneration seedlings were studied. The results show that: (1) The average crown width and mean base diameter of regenerated seedlings were in the order of low-altitude convex land>high-altitude slope>low-altitude concave land>high-altitude steep slope. The average plant height on high-altitude steep slopes was considerably lower than that in the other three microtopographies. Thus, different altitudes, slopes, aspects, and slope positions considerably affected the survival rate and growth process of regeneration seedlings. (2) The renewal seedling density and average plant height under different microtopographic conditions were as follows: low-altitude concave land, low-altitude convex land, high-altitude slope, and high-altitude steep slope. (3) Most of the regenerated seedlings showed an aggregated distribution under different microtopography in the order of high-altitude steep slope>low-altitude concave>low-altitude convex>high-altitude slope. (4) The results of the correlation analysis showed that there was a significant correlation between altitude, slope, slope position, and regenerated seedlings (P<0.05). In summary, the natural regeneration of Picea crassifolia forest was significantly affected by microtopographic habitat (P<0.05), and seedlings were more suitable for settlement and growth in low-altitude convex land and low-altitude concave land.
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2020-11-20 Cooperative journals: 《干旱区地理》
Abstract：以祁连山北麓中段青海云杉林为研究对象，利用5套土壤温湿度自动监测系统对海拔2 500～3 300 m的青海云杉连续监测3 a，旨在探讨青海云杉林土壤水热的变化特征及土壤水热间的互作效应。结果表明：（1）7：00～19：00，土壤温度整体上呈升高趋势，8：00土壤均温最低，为1.03 ℃，18：00土壤均温最高，为1.32 ℃；土壤湿度的变化幅度较小，且差异不显著（P＞0.05）。（2）冷期（1～4月、11～12月）、暖期（5～10月），各占全年的50%；8月前随月份增大土壤温湿度增大，月份增大1月，土壤均温增大2.21 ℃，湿度增大0.021 m3·m-3，8月后随月份增大逐渐减小，月份增大1月，土壤均温减小3.12 ℃，湿度减小0.017 m3·m-3。（3）土壤温度与海拔之间有负相关关系（R2＝0.81，P＜0.05）；土壤湿度与海拔之间存在二项式相关关系（R2＝0.95，P ＜0.05）。（4）土壤温度与土层深度间呈负相关关系（P ＜0.05），而土壤湿度与土层深度呈线性正相关关系（P ＜0.05），土层每增加一层，土壤均温减小0.142 ℃，湿度约增加0.009 m3·m-3。（5）青海云杉林土壤温度和湿度间呈显著线性负相关关系（P ＜0.05）。
Subjects: Geosciences >> Geography submitted time 2019-11-15 Cooperative journals: 《干旱区地理》
Abstract：以祁连山排露沟流域青海云杉林为研究对象，研究了海拔梯度上土壤肥力因子的分布特征及变化规律，并运用主成分分析法对青海云杉林土壤肥力状况进行了评价。结果表明：（1）研究区土壤呈碱性，pH值均大于8.0；高海拔地区（3 300 m）含水量达到过饱和状态，各土层含水量均大于100%；随海拔升高，全氮含量呈增大趋势，全钾含量呈减小趋势，而全磷含量呈先减小后增大趋势；不同海拔梯度速效磷含量差异不显著（P>0.05），海拔3 300 m处速效钾含量显著高于其他海拔段（P3 200 m>3 100 m>3 000 m>2 900 m。
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