Laboratory and field measurement of magnetic susceptibility of Japanese agricultural soils for rapid soil assessment
Laboratory and field measurement of magnetic susceptibility of Japanese agricultural soils for rapid soil assessment
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DOI：
10.1016/j.geoderma.2021.115013
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发表时间：
2021-07
期刊：
影响因子：
6.1
通讯作者：
N. Moritsuka;K. Matsuoka;K. Katsura;S. Sano;J. Yanai
中科院分区：
文献类型：
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作者：
N. Moritsuka;K. Matsuoka;K. Katsura;S. Sano;J. Yanai
测量土壤的体积磁化率（κ）可以快速评估土壤。在本研究中，我们在国家和农场尺度上测量了日本农业表层土壤的κ值，以评估土壤κ值与其他土壤性质之间的尺度依赖关系，并检查在实验室和现场测量的κ值的可重复性。采用手持式田间传感器测量两组样本：(1)全日本164个样本（国家尺度），(2)高津县246个样本和三帆县117个（农场尺度）样本（39个点× 3次）。实验室测量结果表明，全国尺度样品土壤κ变异系数为112%，高津样品为13%，三丰样品为33-37%。在国家尺度上的巨大变化是由于几个正异常值，这些正异常值被WRB分类为Vitric或silandolols。样本的重复测量可以估计样本内κ的变化，如果变异系数超过10%，则认为数据不可靠。利用可靠数据进行相关分析表明，在国家尺度上，κ值与结构Fe （total Fe - Fed）呈正相关，其次是aloo和冰岛性质（Alo+ 1/2Feo）。相反，在农场尺度上采集的米富恩样品，κ值与含沙量呈正相关，其次是钾饱和百分比。39个米富尼位点的土壤κ变异系数几乎都在10%以下。场地内的变化可能是由于土壤表面与传感器之间的不完全接触。我们的研究结果表明，测量日本农业表层土壤的κ可以帮助区分玻璃质或硅质安土与其他土壤，并在农场和国家尺度上估计与κ相关的土壤性质。
Measuring volume magnetic susceptibility (κ) of soil allows rapid soil assessment. In this study, we measured the κ value of agricultural surface soils in Japan at national and farm scales in order to evaluate the scale-dependent relationship between soil κ and other soil properties and to examine the repeatability of the κ value measured in the laboratory and in the field. A handheld field sensor was used to measure two sample sets: (1) 164 samples collected throughout Japan (national scale), and (2) 246 samples collected from paddy fields in Takatsuki and 117 (39 sites × 3 times) samples collected from paddy fields in Mifune (farm scale). Laboratory measurements showed that the coefficients of variation of soil κ were 112% for the national scale samples, 13% for the Takatsuki samples, and 33–37% for the Mifune samples. The large variation at the national scale was due to several positive outliers, which were classified as Vitric or Silandic Andosols by the WRB classification. Repeated measurement of samples enabled estimation of the within-sample variation in κ, and the data was considered unreliable if the coefficient of variation exceeded 10%. The correlation analysis using the reliable data indicated that at the national scale, the κ value was most positively correlated with structural Fe (total Fe minus Fed) followed by Aloand the andic properties (Alo+ 1/2Feo). In contrast, for the Mifune samples collected at the farm scale, the κ value was most positively correlated with sand content followed by K saturation percentage. Field measurements of soil κ at the 39 Mifune sites indicated that the coefficients of variation of κ at the same site were almost all below 10%. The within-site variations were due probably to the incomplete contact between the soil surface and the sensor. Our results suggest that measuring κ of agricultural surface soils in Japan can help to distinguish Vitric or Silandic Andosols from other soils, and to estimate the κ-related soil properties at the farm and national scales.