Large scale soil survey and mapping based on the spatial variation of soil horizons.

This paper put forward a proposal of large-scale soil survey and mapping based on characterization of the spatial variation of soil horizons.The framework of the method can be divided into four steps:(i) positioning of observation points with Global Positioning System(GPS),observing soil profiles and classifying soil horizon;(ii) determining soil types in the studied area,and establishing a database of soil attributes and spatial parameters;(iii) analyzing the spatial variations of thickness of the selected soil horizons(diagnostic horizon) supported by the Geographical Information System(GIS),and defining standards for soil classification;(iv) overlay processing of soil horizon maps,and developing a soil map.The method was applied to soil survey of a 28.3 hm~2 low hill where soils were developed from shale.Three soil series were identified in the studied area.The results indicated that the method was applicable for large-scale soil survey with a high accuracy(94%).