黄土高原土石山区土壤密度的坡面变化——以六盘山香水河小流域为例

发布时间：2018-01-15 04:03

本文关键词：黄土高原土石山区土壤密度的坡面变化——以六盘山香水河小流域为例　出处：《林业科学研究》2016年04期 　论文类型：期刊论文

【摘要】：[目的]土壤密度是最基本的森林土壤水文物理性质参数,为了定量描述土壤密度随坡位的变化和影响因素,研究不同坡面土壤密度的空间异质性。[方法]在宁夏六盘山半湿润区香水河小流域,选择华北落叶松人工林和天然灌丛2个典型坡面,按坡位从上到下设置连续样地。2014年进行了森林土壤调查,在样地内掘土壤剖面,采用环刀法,分层测定土壤密度。[结果]在1 m深土层内,土壤密度(Y,g.cm-3)随土层(X,cm)加深呈线性增大,拟合关系式:华北落叶松坡面为Y1=0.755 5+0.007 7X(R2=0.99),天然灌丛坡面为Y2=0.919 5+0.004 7X(R2=0.98),其原因包括植被根系活动、土壤生物活动、砾石含量等的土层差异;在2个坡面上,0 100 cm土层平均土壤密度均有明显坡位差异,且2个坡面的沿坡整体变化趋势不相同,华北落叶松坡面从坡顶到坡脚是先逐渐增大,后趋于稳定;天然灌丛坡面从坡顶到坡脚是"增大-减小-增大"的趋势,不同土层土壤密度的坡面变化也各不相同。在华北落叶松林坡面引起土壤密度坡位差异的主要原因是海拔,而在天然灌丛坡面是植物生长状况;2个坡面的土壤密度平均值均出现在相对坡长的0.4 0.5处。坡面上各样地的平均土壤密度和坡面平均值的差值(Z,g.cm-3)随相对水平坡长(样地离开坡顶水平距离和整个坡面水平坡长的比)(X,m)变化的回归关系式分别为:华北落叶松坡面Z1=-0.139X2+0.25X-0.080 1(R2=0.93),天然灌丛坡面Z2=0.494 4X3-0.767 2X2+0.340 3X-0.040 5(R2=0.95)。[结论]华北落叶松林坡面和天然灌丛坡面的土壤密度都存在明显的坡位变化,但变化格局和主要影响因素不同。基于土壤密度坡面变化的拟合关系,可实现从特定坡位测定值推算坡面平均值的尺度转换。
[Abstract]:[Objective] soil density is the most basic hydrophysical property parameter of forest soil. In order to quantitatively describe the variation and influence factors of soil density with slope position, the spatial heterogeneity of soil density on different slopes was studied. [Methods] two typical slopes of Larix gmelini plantation and natural shrub were selected in Xiangshuihe small watershed of Liupanshan sub-humid area in Ningxia. In 2014, a forest soil survey was carried out. Soil profile was excavated in the sample, and soil density was determined by means of circular knife method. [Results] in 1 m deep soil layer, the soil density (YC 路cm-3) increased linearly with the deepening of the soil layer (X ~ (+) C ~ (m-3)). The fitting formula is Y1C 0.755 5 0.007 7 XC R2N 0.99) on the slope of Larix gmelinii. The natural shrub slope is Y2N 0.919 5 0.004 7XC R2N 0.98, which is caused by the difference of soil layer such as vegetation root activity, soil biological activity, gravel content and so on. The average soil density of 0 100 cm soil layer on two slopes had obvious slope position difference, and the overall variation trend of the two slopes along the slope was different, and the slope of North China Larch gradually increased from the top to the foot of the slope. Then it tends to be stable; The natural shrub slope from the top to the foot of the slope is the trend of "increase-decrease-increase". The variation of soil density in different soil layers is also different. The main reason for the difference of soil density slope is elevation, while in natural shrub slope, plant growth is the main reason. The average soil density of the two slopes was 0.4 0.5 relative to the slope length, and the difference between the average soil density on the slope and the average value of the slope was Z. G.cm-3) with the relative horizontal slope length (the ratio of the horizontal distance from the slope top to the horizontal slope length of the whole slope). M) the regression equation of the variation is Z1 + -0.139X2 0.25X-0.0801 (R2N) 0.93 on the slope of Larix gmelinii. Natural thicket slope Z2N 0.494 4X3-0.767 2X2 0.340 3X-0.040 5C R2O 0.95. [Conclusion: the soil density of Larix gmelini forest and natural shrub slope has obvious slope position change, but the change pattern and main influencing factors are different, based on the fitting relation of soil density slope change. The scale conversion of the mean value of the slope surface can be realized from the measured value of the specific slope position.
【作者单位】：北京林业大学水土保持学院;中国林业科学研究院森林生态环境与保护研究所国家林业局森林生态环境重点实验室;中南林业科技大学;
【基金】：国家自然科学基金项目(41390461,41471029,41230852) 科技部科技基础性工作专项(2014FY120700);科技部“十二·五”农村领域国家科技计划(2012BAD22B030102) 国家林业局宁夏六盘山森林生态站和宁夏回族自治区生态修复与多功能林业综合研究中心资助
【分类号】：S152
【正文快照】： 土壤密度是土壤最基本的一个物理性状,它对土壤的透气性、入渗性能、持水能力、溶质迁移及抗蚀能力都具有重要影响[1-5]。土壤密度受到气候、母岩、地形、植被和土壤生物以及成土时间等多个因素的影响。因此,在环境条件存在差异的坡面上,必然存在土壤密度的坡位差异,且具有一

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