Dataset of Soil hydraulic properties of Valle Telesina (Italy)

The dataset contain a .xls file with the hydraulic properties georeferenced of 47 soil profiles of the "Valle Telesina (Italy) site, according to the parametrization of the van Genuthen-Mualem model (van Genuchten, 1980). Moreover a zipped folder with the shape files for the same area is provided. Following there is the description of the methods applied for the soil hydraulic characterization: Undisturbed soil samples were collected from the horizons using cylindrical steel samplers (8.5 cm diameter and 12.0 cm high). In the laboratory, the samples were saturated by slowly wetting from the bottom in order to remove all the air entrapped in the soil. The maximum water content,θ₀, was gravimetrically determined and the saturated hydraulic conductivity, ks, was measured by a falling-head permeameter. Then, the Wind method was applied to simultaneously determine the water retention and hydraulic conductivity functions by subjecting the soil samples to an evaporation process. After sealing the bottom surface to prevent drainage, during the evaporation process - at appropriate pre-set time intervals - the weight of the whole sample and the pressure head at three different depths were measured. An iterative procedure was applied for estimating the water retention curve from these measurements. Then, the instantaneous profile method was applied to determine the unsaturated hydraulic conductivity. θr, θs, α and n parameters were derived by fitting the soil water retention data; under the restriction m=l−l/n, τ and k₀ parameters were derived by fitting the hydraulic conductivity data. Details of the tests and overall calculation procedures are described in Basile et al. (2012). The parameters obtained in the laboratory were then scaled to better reproduce the field behaviour by following the procedure suggested by Basile et al. (2003; 2006). Finally, for the few soils having considerable stone content, a correction of θs and k₀, to take into account the stoniness, was applied (Coppola et al., 2013). References: Van Genuchten, M. T. (1980). A closed-form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Science Society of America Journal, 44(5), 892–898. Basile, A., Buttafuoco, G., Mele, G., & Tedeschi, A. (2012). Complementary techniques to assess physical properties of a fine soil irrigated with saline water. Environmental Earth Sciences,66(7), 1797–1807. Basile, A., Ciollaro, G., & Coppola, A.(2003). Hysteresis in soil water characteristics as a key to interpreting comparisons of laboratory and field measuredhydraulic properties.Water Resources Research, 39(12). Basile, A., Coppola, A., De Mascellis, R., & Randazzo, L. (2006). Scaling approach to deduce field unsaturated hydraulic properties and behavior from laboratory measurements on small cores. Vadose Zone Journal,5(3), 1005–1016. Coppola, A., Dragonetti, G., Comegna, A., Lamaddalena, N., Caushi, B., Haikal, M., & Basile, A. (2013). Measuring and modeling water content in stony soils. Soil and Tillage Research,128, 9–22.本数据集包含一份.xls文件，内含意大利特雷西纳谷（Valle Telesina）场地47个土壤剖面的地理参考水力特性数据，基于van Genuchten-Mualem模型（van Genuchten, 1980）的参数化方法构建。此外还提供了包含该区域对应Shapefile（形状文件）的压缩文件夹。 以下为土壤水力特性表征所用方法的详细说明： 采用圆柱形钢制采样器（直径8.5 cm，高度12.0 cm）从土壤发生层采集原状土样。实验室中通过从底部缓慢浸润的方式使土样饱和，以排出土壤中截留的全部空气。采用重量法测定最大含水量θ₀，并通过落头渗透仪测量饱和导水率k_s。随后采用Wind法，通过对土样进行蒸发过程，同时测定土壤持水曲线与导水率函数。在密封土样底部以防止排水后，蒸发过程中按照预设的合适时间间隔，测量整个土样的重量以及三个不同深度处的压力水头。通过迭代流程从上述测量数据中拟合得到土壤水分特征曲线。随后采用瞬时剖面法确定非饱和导水率。通过拟合土壤持水数据，推求出θ_r、θ_s、α及n参数；在约束条件m=1−1/n下，通过拟合导水率数据推求出τ与k₀参数。相关试验与整体计算流程的细节可参见Basile等人（2012）的研究。 随后按照Basile等人（2003；2006）提出的方法，对实验室获得的参数进行尺度转换，以更好地复现田间实际行为。最后，针对少数石块含量较高的土壤，采用校正方法对θ_s与k₀进行修正，以考虑砾石含量的影响（Coppola等人，2013）。 参考文献： Van Genuchten, M. T. (1980). 预测非饱和土壤导水率的闭合形式方程. 美国土壤学会志, 44(5), 892–898. Basile, A., Buttafuoco, G., Mele, G., & Tedeschi, A. (2012). 评估咸水灌溉细粒土壤物理特性的互补技术. 环境地球科学, 66(7), 1797–1807. Basile, A., Ciollaro, G., & Coppola, A. (2003). 土壤水分特征曲线的滞后现象：解释实验室与田间测得水力特性对比的关键. 水资源研究, 39(12). Basile, A., Coppola, A., De Mascellis, R., & Randazzo, L. (2006). 基于小型土芯实验室测量结果推导田间非饱和水力特性与行为的尺度转换方法. 包气带期刊, 5(3), 1005–1016. Coppola, A., Dragonetti, G., Comegna, A., Lamaddalena, N., Caushi, B., Haikal, M., & Basile, A. (2013). 砾石土壤含水量的测量与建模. 土壤耕作研究, 128, 9–22.