摘要
在宁夏六盘山选择华北落叶松林坡面,利用TRIME-PICO土壤水分测定仪,在2015年5—11月对48个测点分12次测定了不同厚度土层(0—20,0—40,0—60cm)的体积含水量的时间动态,并采用累积概率函数、相对偏差及Spearman秩相关系数等方法,分析评价了坡面土壤体积含水量的时间稳定性。结果表明:土壤体积含水量在时间和空间上均存在中等变异,且变异程度随土层加厚而逐渐降低,表现为0—40,0—60cm土层体积含水量的累积概率在干旱和湿润2种极端条件下的变化均小于0—20cm土层。0—20,0—40,0—60cm土层体积含水量的平均相对偏差的变化范围分别为(-43.5%)^(47.9%),(-42.9%)^(49.9%)和(-46.9%)^(40.0%);平均相对偏差的标准差(SDRD)呈现出随土层加厚而逐渐降低的变化趋势,在0—20,0—40,0—60cm土层依次为11.1%,8.3%,7.8%。在整个研究期间,Spearman秩相关系数在不同土层厚度条件下始终保持较高水平(0.7以上),且呈极显著相关,坡面上不同土层的体积含水量具有较高的时间稳定性。基于土壤含水量的时间稳定性特征,确定了研究坡面上不同土层厚度的体积含水量平均值的代表性测点,可利用这些代表性测点的土壤体积含水量测定值估计相应土层厚度的坡面平均值。
The volumetric soil moisture dynamics at different soil depth（0—20cm,0—40cm and 0—60cm）on a Larix principis-rupprechtii plantation slope was measured by TRIME-PICO from May to November in2015 in the small watershed of Xiangshuihe of Liupan Mountains.The temporal stability of soil moisture was analyzed by the cumulative probability functions,relative differences and Spearman rank correlation coefficients.The results showed that the soil moisture had a moderate variability both in time and space,and the degree of variation decreased gradually with increasing thickness of soil layers.The variability of cumulative probability for thicker soil layers（0—40cm and 0—60cm）was lower than that of the 0—20cm soil layer under both dry and wet conditions.The mean relative differences of the soil moisture for the soil layers of0—20cm,0—40cm and 0—60cm ranged from（-43.5%）to（47.9%）,（-42.9%）to（49.9%）and（-46.9%）to（40.0%）,respectively.The standard deviation of the mean relative differences（SDRD）decreased gradually with the increasing soil layer thickness.The SDRD of 0—20cm,0—40cm and 0—60cm soil layer were11.1%,8.3% and 7.8%,respectively.The soil moisture of all 3soil thicknesses studied had a higher Spearman rank correlation coefficient（bigger than 0.7）and with a significant correlation,suggesting a higher temporal stability existed for the soil moisture of all the soil thickness studies.The representative pointsof the mean soil moisture of different soil layer thicknesses on the Larix principis-rupprechtii plantation slope were determined based on the temporal stability characteristic of soil moisture.With these representative points,the mean soil moisture of different soil layer thicknesses of the whole slope could be easily estimated.
出处
《水土保持学报》
CSCD
北大核心
2017年第1期153-159,165,共8页
Journal of Soil and Water Conservation
基金
国家自然科学基金项目(41471029,41390461,41230852)
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项目(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项目
关键词
华北落叶松坡面
土壤含水量
时间稳定性
Larix principis-rupprechtii plantation slope
soil moisture
temporal stability
