Digital Soil Mapping and Best Management of Soil Resources: A Brief Discussion with Few Case Studies

Soil plays a key role in agricultural production system by supporting plant growth as well as in hydrological cycle by partitioning rainwater into runoff and infiltration. Therefore, knowledge on soil properties helps in better management of both soil and water resources for sustainable crop production. However, soils vary largely in space and therefore characterizing it for a particular landscape with a set of soil parameters is a difficult task. Often, there is need to collect multiple soil samples from a landscape for characterization purpose in order to minimize the spatial variation effect and is not always feasible. Most of the times, a homogeneous zone is assumed with similar soil properties to eliminate the variation effect. Soil mapping helps in characterizing the soil resources in a better way and recently introduced digital soil mapping approach is more appropriate for this purpose. In this approach, spatial variation of soil properties and its relation with other landscape and environment variables in the form of ‘scorpan’ factors are considered while mapping soil properties in a spatial domain. Mathematical models are also established between soil properties and environment variables exploiting the available legacy soil data and hugely available digital data on earth features in recent times. Hyperspectral soil signatures have also a potential role to improve the digital soil products further. In this chapter, we discuss the basics of digital soil mapping approach and its needs, semivariogram fitting, kriging and its variations, accuracy and uncertainty of digital maps, role of pedotransfer (PTF) and spectrotransfer (STF) models in digital soil mapping, future prospect of hyperspectral signatures in mapping soil properties and few cases studies on digital soil mapping. Finally, it is expected that digital soil maps are available in different IT platforms, e.g. internet, desktop computer, mobile apps, webGIS platform, etc., to make them useful to end users.