Wimalasiri Eranga M, Jahanshiri Ebrahim, Suhairi T A S T M, Mapa Ranjith B, Karunaratne Asha S, Vidhanarachchi Lal P, Udayangani Hasika, Nizar N M M, Azam-Ali Sayed N
Crops for the Future UK, Chelmsford, Essex CM2 7PJ, England, UK.
Department of Soil Science, Faculty of Agriculture, University of Peradeniya, Sri Lanka.
Data Brief. 2020 Sep 24;33:106342. doi: 10.1016/j.dib.2020.106342. eCollection 2020 Dec.
Soil data for Sri Lanka are available through semi-detailed series maps that were developed based on limited soil profile data combined with expert knowledge. This data plays a vital role in decisions at national and regional levels. However, the present format of this database does not allow for their wider use in crop simulation modelling and other related agricultural research that require finer scale data. This is due to the fact that cross-country profile data are not harmonised based on standard depths. Several attempts were made to produce digital soil data for Sri Lanka at different geographic scales, however, a completely harmonised data that covers variability across depths and properties is yet to be made available. In this article, we describe the first version of the open digital soil database that was developed using a database of 122 locations across the country. Soil properties were harmonised for standard depths using equal-area quadratic smoothing splines. Out of several interpolation methods that were evaluated for univariate interpolation, maps which were produced with the least overall error (RMSE) in the process of cross-validation were selected. The newly developed digital soil database contains 9 soil properties; pH, bulk density, cation exchange capacity, organic carbon, volumetric moisture content at 0.33 and 15 bars levels, sand silt and clay content. Moreover, the data are available for five standard depth layers as 0-5, 5-15, 15-30, 30-60 and 60-100 cm in raster format at 1 km spatial resolution. Both interpolated property maps and their error maps were stored in an open repository and made available for public use. The first version of all maps is also showcased online through open web mapping services. The repository will be gradually updated with higher resolution and more accurate maps as more samples become available and better interpolation method are used. This data could provide complementary information for insight generation at finer scales where limited local informaiton about soils hinders agricultural development.
斯里兰卡的土壤数据可通过半详细系列地图获取，这些地图是根据有限的土壤剖面数据并结合专家知识编制而成的。这些数据在国家和地区层面的决策中发挥着至关重要的作用。然而，该数据库目前的格式不允许其在作物模拟建模和其他需要更精细尺度数据的相关农业研究中得到更广泛的应用。这是因为跨国剖面数据没有根据标准深度进行统一。此前曾多次尝试在不同地理尺度上生成斯里兰卡的数字土壤数据，然而，一个涵盖深度和属性变异性的完全统一的数据仍未提供。在本文中，我们描述了使用全国122个地点的数据库开发的开放数字土壤数据库的第一个版本。利用等面积二次平滑样条对标准深度的土壤属性进行了统一。在对单变量插值评估的几种插值方法中，选择了在交叉验证过程中总体误差（均方根误差）最小的地图。新开发的数字土壤数据库包含9种土壤属性；pH值、容重、阳离子交换容量、有机碳、0.33和15巴压力水平下的体积含水量、砂、粉砂和粘土含量。此外，数据以1公里空间分辨率的栅格格式提供五个标准深度层，即0 - 5、5 - 15、15 - 30、30 - 60和60 - 100厘米。插值属性图及其误差图都存储在一个开放的存储库中，供公众使用。所有地图的第一个版本也通过开放网络地图服务在线展示。随着更多样本的获取和采用更好的插值方法，该存储库将逐步更新为更高分辨率和更准确的地图。这些数据可以提供补充信息，以便在土壤局部信息有限阻碍农业发展的更精细尺度上生成见解。
