Developing North American Soil Properties for Climate and Hydrology Applications—Mexico

The North American Soil Properties (NOAM-SOIL) project goal is to create a three-dimensional soil properties geographic database suitable for use with climate and hydrologic models for North America. An automated GIS method patterned after manual procedures used by pedologists to link existing soil physical property measurements with soil map polygons was developed; 3,037 georeferenced pedon measurements were evaluated for linkage to the first, second, and third soil components for 8,260 polygons of the 1:1,000,000-scale Soil Map of Mexico. The linkage procedure relied on distance from the polygon and a goodness-of-match score that compared the polygon soil component and the soil pedon taxonomy, physical/chemical phase, and landscape location attributes.

Pedons that were spatially coincident with a soil polygon and matched at the soil type (suborder) level were assigned as the “best” pedon. The number of matches of soil phase data resolved conflicts.

Remaining soil polygons were processed for each of the three soil components and each of five complementary spatial databases. For each polygon, the pedon nearest to a polygon node that matched the soil component’s soil type and the value of the complementary database was added to the polygon’s list of matching pedons.

The best pedon was assigned to each soil polygon component based on the number of complementary database matches, the number of phase matches, and the distance between the pedon and the polygon edge.

A dominant soil surface texture map with metadata maps for the Mexican portion of North America is among preliminary NOAM-SOIL products. NOAM-SOIL is supported by the National Oceanic and Atmospheric Administration–Global Energy Water-Cycle Experiment Continental-Scale International Project No. GC98-300. The authors wish to acknowledge the contributions of Instituto Nacional de Estadistica, Geografia e Informatica (INEGI) and Inventorio Nacional de Suelos-DGRyCS-Secretaria de Medio Ambiente y Recursos Naturales–Mexico.