Utilizing spatial technology as a decision-assist tool for precision grading of salt-affected soils

ABSTRACT:

Precision land leveling can expose subsurface soil layers that have elevated levels of exchangeable sodium and can deposit this sodium-laden material on the original soil surface in other parts of the field. Results from two case studies where a geographic information system (GIS) and global positioning system (GPS) were utilized to assist with land-leveling decisions for soils containing elevated soluble salts and sodium are discussed. In both cases, the spatial distribution of Na, exchangeable sodium percentage (ESP), and electrical conductivity (EC) were overlain with maps depicting the pattern of removal and re-deposition of soil. From this analysis, an estimate of the potential sodium hazard that might result from precision grading was determined. Decisions derived from traditional, composite sampling were compared to decisions made with site-specific technology. The spatial technology approach utilized in this work provided decision makers with reasonable assurance about their precision grading decisions apriori