| 引用本文: | 秦京涛,吕谋超,邓 忠,等.豫北砂质壤土地区不同尺度农田土壤含水率空间变异性研究[J].灌溉排水学报,2019,38(7):10-16. |
| ,et al.豫北砂质壤土地区不同尺度农田土壤含水率空间变异性研究[J].灌溉排水学报,2019,38(7):10-16. |
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| 摘要: |
| 【目的】揭示豫北地区农田0~1 m土层土壤含水率空间分布与变异状况。【方法】在中国农业科学院新乡综合试验基地玉米田选取一个50 m×50 m的区域，然后在其内部选取10 m×10 m、2 m×2 m的区域，共形成3种采样尺度，分别标记为L、M、S尺度，并于2016年8月和9月，在各尺度内分别等间距选取36个取样点。基于地统计学理论，对0~1 m土层土壤平均含水率进行分析。【结果】各尺度土壤含水率正态分布置信水平高于对数正态分布，尺度越大，土壤含水率分布属于正态分布置信水平越低；对于土壤含水率均值，L尺度与M尺度差异较大，M尺度与S尺度差异较小；总体上，土壤含水率的置信区间、标准差以及变异系数均随尺度的减小而减小；L尺度内变异函数值总体上随着滞后距的增大而增大，而M尺度和S尺度变异函数值没有明显的变化趋势，相对比较稳定；总体上相同置信水平与估算精度条件下，估算样本均值所需的样本数量随尺度的减小而减小；与置信水平相比，估算精度对合理取样数量的影响大。【结论】不同尺度土壤含水率的概率分布与大部分统计特征值均会随着尺度的变化而产生有规律的变化，尺度越大，土壤含水率分布越偏离正态分布，其空间变异性也越强。 |
| 关键词: 土壤含水率； 空间变异性； 空间分布； 正态分布； 变异系数； 变异函数 |
| DOI：10.13522/j.cnki.ggps.20180452 |
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| Spatial Variability of Soil Moisture at Different Scales in Sandy Loam in Northern Henan Province |
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QIN Jingtao, LYU Mouchao, DENG Zhong, GU Shaowei, GAO Jianmin
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Farmland irrigation Research Institute, Chinese Academy of Agricultural Sciences/Key Laboratory of Water Saving Irrigation Engineering, Ministry of Agriculture, Xinxiang 453003, China
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| Abstract: |
| 【Objective】Soil moisture plays an important role in ecosystem function and hydrological processes. This paper investigated the hieratical distribution of soil moisture at different scales over a maize field. 【Method】The studied site was a 50 m×50 m plot at the Experiment Station of Chinese Academy of Agricultural Sciences in Xinxiang, Henan province. We measured soil moisture in 0~100 cm soil from 36 locations at 10 m×10 m and 2 m×2 m scale, respectively. 【Result】 Geostatistical analysis revealed that the soil moisture was normally distributed and its confidence level at every scale was higher than that of logarithmic normal distribution. The value of the confidence level decreased as the sampling scale increased, and the difference between average soil moisture content at fine scale and moderate scale was smaller than the difference between moderate scale and large scale. In general, the confidence interval, standard deviation and coefficient of variation of the soil moisture increased with sampling scale. At large scale, the semi-variance function increased with lag distance, while at small and moderate scale, the variation function appeared to be independent of the lag distance. To achieve the same confidence level and accuracy in estimating soil moisture, the number of samples needed to be taken from the field increased with sampling scale. We also found that in estimating soil moisture, the number of samples needed to be taken depended on the required accuracy more than on the confidence level. 【Conclusion】 The probabilistic distribution and statistical characteristics of soil moisture in the field was scale-dependent. In estimating soil moisture, the number of sampled taken from the field needs to consider the scales to which the measured data will be applied. |
| Key words: soil moisture content; spatial variability; spatial distribution; normal distribution; coefficient of variability; semi-variogram |
