科尔沁沙丘—草甸相间地区土壤田间持水量的综合测定与变异性分析

发布时间：2018-09-02 07:27

【摘要】：以内蒙古科尔沁沙丘.草甸相间地区为研究区,野外布设并取样231个土壤取样点,采用威尔科克斯法测定上壤田间持水量：均匀选取其中49个点作为围框淹灌法测试点,并在20cm处取土样采用水分特征曲线法获得各点的田间持水量。选择研究区内具有代表性的6个：土壤生态点,分析一场降雨后0～40cm土壤的含水率的变化。对比分析不同方法得到的田间持水量数据,有以下结论：1.实验区划分为八种地貌类型,对土壤进行土壤理化参数分析。将田间持水量与饱和含水量进行相关性分析,两者表现出极好的相关性。2.4种测定方法得到的田间持水量在不同地貌类型区的变化规律大体一致,但数值差异很大。压力板法沙丘区选择pF 1.8法,草甸区选择pF2.52法可得到与威尔科克斯法相同的测试结果；威尔科克斯法与灌水法和天然降水法测试结果之间存在很大的差距：同时,围框淹灌法还受到前期降雨的影响,建议采用围框淹灌法测量田间持水量时应避开降雨实施或延长测定时间；3.天然降水法在降雨量为60mm左右时,地下水位埋深大的沙丘区在0～40cm以内的土壤可以获得较准确的田间持水量数值,沙丘区的建议取样时间为12～24h,地下水位埋深较小的草甸区受地下水影响,无法获得准确的田间持水量的数值。威尔科克斯法不受地下水位影响,与脱水时间相关,选择合适的脱水时间即可得到正确的田间持水量值,砂土选用36-40h,砂壤土与壤砂土选用44～48h。4.基于威尔科克斯法获得的田间持水量数据,运用地统计学分析研究区土壤田间持水量的空间分布。结果为：田间持水量表现出强烈的空间相关性,经交义验证,选择最佳的变差函数，并运用泛克里格插值法模拟土壤特性的空间分布。整体呈现出以湖为中心向四周逐渐减小的趋势,与干容重的相关性最好,呈负相关关系。
[Abstract]:To Inner Mongolia Horqin sand dunes. The meadow interphase area was used as the study area, 231 soil sampling points were set up and sampled in the field. The field water holding capacity of upper soil was determined by Wilcox method. Forty-nine of them were chosen as the test points of the frame flooding irrigation method. The field water holding capacity of each point was obtained by the method of water characteristic curve at 20cm. Six representative soil ecological sites in the study area were selected to analyze the change of soil moisture content of 0~40cm after a single rainfall. Comparing and analyzing the field water capacity data obtained by different methods, the conclusions are as follows: 1. The experimental area was divided into eight geomorphological types and the soil physical and chemical parameters were analyzed. The correlation analysis between field water holding capacity and saturated water content showed that there was a good correlation between them. The variation law of field water holding capacity in different geomorphological type areas was basically the same, but the numerical value was very different. The pF 1.8 method is chosen in the pressure plate method and the pF2.52 method is chosen in the meadow area, and the test results are the same as those obtained by the Wilcox method, and there is a big gap between the Wilcox method and the irrigation method and the natural precipitation method: at the same time, The frame flooding irrigation method is also affected by the early rainfall. It is suggested that the rainfall should be avoided or the measuring time should be prolonged when the surrounding frame flooding irrigation method is used to measure the field water holding capacity. When the rainfall of natural precipitation is about 60mm, the soil in the dune area with large groundwater level buried in 0~40cm can obtain more accurate field water holding capacity. The recommended sampling time in sand dune area is 12 ~ 24 hours. The meadow area with lower groundwater level is affected by groundwater, so it is impossible to obtain accurate field water holding capacity. Wilcox method is not affected by groundwater level and is related to dehydration time. The correct field water holding value can be obtained by selecting suitable dehydration time. Sand soil is chosen for 36-40 hours, sand loam and loam soil for 44 ~ 48h. Based on the field water holding data obtained by Wilcox method, the spatial distribution of soil field water capacity in the study area was analyzed by geostatistics. The results were as follows: the field water holding capacity showed strong spatial correlation. The optimal variation function was selected and the spatial distribution of soil characteristics was simulated by pankriging interpolation. The whole showed a decreasing trend with the lake as the center, and the correlation with dry bulk density was the best, with a negative correlation.
【学位授予单位】：内蒙古农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S812.2

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