GEOSTATISTICAL ANALYSIS OF SOIL CHEMICAL PROPERTIES FROM NESTED GRIDS

A nested grid sampling scheme was used to collect and analyze data to generate soil chemical property variation maps. Several regular sampling grids were nested within each other to achieve a variety of sample spacings. Soil samples were taken in a 200 m × 200 m area on a 50 m regular grid that included nests on 10, 2, and 0.5 m grids. The samples were analyzed for salt pH, percent organic matter, plant available phosphorus, and exchangeable potassium. Summary statistics and geostatistical analysis of the soil test results showed that pH and potassium were spatially dependent, while organic matter and phosphorus were less spatially dependent at the scale of this study. Nested grid sampling techniques provided an independent way of determining whether spatial dependence was present in the data; however, nesting was found inadequate for semivariance analysis.