SOTER-based soil parameter estimates (SOTWIS) for Central Africa

This harmonized set of soil parameter estimates for Central Africa, comprising Burundi, the Democratic Republic of the Congo and Rwanda, was derived from the Soil and Terrain Database for Central Africa (SOTERCAF ver. 1.0) and the ISRIC-WISE soil profile database, using standardized taxonomy-based pedotransfer (taxotransfer) procedures.

The land surface of Central Africa, comprising some 2.4 million km2, has been characterized using 244 unique SOTER units, corresponding with 504 polygons. Each SOTER unit may consist of up to 6 soil components; each of these has been characterized by a representative profile. The main soil units mapped for the region have been characterized using 167 real profiles, selected by soil experts as being regionally representative for these units. The associated soil analytical data have been derived from soil survey reports.

Gaps in the measured soil data have been filled using a scheme of using a step-wise procedure that uses taxotransfer rules. These rules were developed using some 5672 soil profiles, held in the ISRIC-WISE database, having similar FAO soil unit names as those reported in the primary SOTERCAF database.

Parameter estimates are presented by soil unit for fixed depth intervals of 0.2 m to 1 m depth for: organic carbon, total nitrogen, C/N ratio, pH(H2O), CECsoil, CECclay, base saturation, effective CEC, aluminium saturation, CaCO3 content, gypsum content, exchangeable sodium percentage (ESP), electrical conductivity of saturated paste (ECe), bulk density, content of sand, silt and clay, content of coarse fragments (less than 2 mm), and available water capacity (-33 kPa to -1.5 MPa). These attributes have been identified as being useful for agro-ecological zoning, land evaluation, crop growth simulation, modelling of soil carbon stocks and change, and analyses of global environmental change.

The current parameter estimates should be seen as best estimates based on the current selection of soil profiles and data clustering procedure. Taxotransfer rules have been flagged to provide an indication of the possible confidence in the derived data.

本数据集为涵盖布隆迪、刚果民主共和国与卢旺达的中非地区整合统一的土壤参数估算成果，其数据源自《中非土壤与地貌数据库》（Soil and Terrain Database for Central Africa, SOTERCAF 版本1.0）以及ISRIC-WISE土壤剖面数据库，通过标准化的基于分类学的土壤传递（taxotransfer）流程生成。

该中非地区陆地总面积约240万平方千米，通过244个独立SOTER单元进行表征，对应504个多边形图斑。每个SOTER单元最多可包含6个土壤组分，各组分均通过代表性剖面完成表征。针对该区域绘制的主要土壤单元，共选取167份经土壤专家认定的区域代表性实测剖面，相关土壤分析数据均源自土壤调查报告。

实测土壤数据的空缺通过分步流程完成填补，该流程采用分类传递规则。此类规则依托ISRIC-WISE数据库中约5672份土壤剖面构建，这些剖面的FAO土壤单元名称与原始SOTERCAF数据库中记录的名称一致。

参数估算结果按土壤单元分类呈现，覆盖0.2 m至1 m的固定深度区间，涵盖以下属性：有机碳、全氮、C/N比、pH(H₂O)、土壤阳离子交换量（CECsoil）、黏粒阳离子交换量（CECclay）、盐基饱和度、有效阳离子交换量、铝饱和度、碳酸钙含量、石膏含量、交换性钠百分比（ESP）、饱和浆体电导率（ECe）、容重、砂粒/粉粒/黏粒含量、粒径小于2 mm的粗碎屑含量以及有效持水容量（-33 kPa至-1.5 MPa）。上述属性已被证实可应用于农业生态区划、土地评价、作物生长模拟、土壤碳库及其变化建模以及全球环境变化分析等领域。

当前的参数估算结果应被视为基于现有土壤剖面选取方案与数据聚类流程得到的最优估算成果。分类传递规则已标注相关信息，以体现衍生数据的潜在置信度。