Development of NWU soil database as a precursor for a national soil database

Abstract

The availability of a high-quality database that captures the spatial variability of soil properties in South Africa, will promote the long-term sustainable use of soil in the country. In agriculture, data on the variability observed within a field is essential to meet the basic objectives of site-specific management of inputs, which will in turn lead to the increased profitability of crop production while protecting the environment and improving the quality of soil. In South Africa, the amount of soil information from Agricultural support organizations, commercial forestry and mining companies, government departments and academic institutions is broad, but not available outside of the holders of the data. The development of a soil database containing standardised soil information will not only contribute to the estimations of present and future soil productivity potential, in South Africa, but will also aid environmentalists in determining land and water limitations when conducting soil degradation risk assessments. The World Soil Information Services (WoSIS) and the Agricultural Research Council of Soil, Climate and Water (ARC-ISCW) point databases were chosen for SWOT analysis to evaluate the Strengths, Weaknesses, Opportunities and Threats that can emerge from the development of a database, and from this the NWU soil database structure was proposed. Soil point data was collected from various sources in South Africa and recorded in the NWU soil database with the accompanying soil morphological and analytical properties. Quality control measures were performed using statistical analysis including basic quality control and outlier detection to evaluate the quality of the recorded data. As a result of the evaluation of the SWOT analysis, the NWU soil database was developed in a way that it can be used to record soil data collected from various sources, recorded in different formats and created for different purposes. The final product of the NWU soil database was composed of a total of 25 sources resulting in a total of 539 soil profiles and 1518 soil horizons. The soil data was quality controlled and used to characterise the soil based on the various soil properties recorded in the soil database. Soil data from various sources can be collected, quality-controlled and recorded in a common soil database, that is complete, comprehensible, and user-friendly. This will lead to the gradual reduction of the paucity of soil data availability in South Africa.