Spatial Mapping of Soil Salinity On a Golf Course with a Mobile Device.

Soil salinity resulting from use of saline irrigation water can cause adverse plant and soil stresses such as: salt-induced drought, nutrient imbalances, toxic ion effects, and creation of sodic soils with associated poor physical conditions.  On saline irrigated sites, soil salinity exhibits a high degree of spatial variability across the landscape and within the soil profile as well as temporal variability in response to site-specific differences in irrigation/rainfall applications, surface and subsurface water movement, and evapotranspiration (ET) patterns. Rapid, detailed mapping of soil salinity patterns on large, complex sites would allow: a) for site-specific leaching rather than using an estimated leaching requirement over a whole area as a water conservation strategy; b) the most saline sites to be identified so that hand salinity monitoring devices could be used to monitor leaching effectiveness, and c) identification of the best areas for installation of in-situ soil salinity sensors for real-time and multi-depth data. An experimental mobile monitoring device based on measuring soil resistivity by a 4-wenner array was used to determine soil salinity on a 1.6 by 3.2 m grid on two golf course fairways (Old Collier Golf Club, Naples, FL). Diverse soils were mapped on three monitoring dates (26 Jan, 30 Mar, and 4 May 2009) with increasing soil salinity.  Plant NDVI (normalized difference vegetative index) was also determined with a spectral reflectance unit with all data GPS designed for use in GIS maps.  Field sampling was used to correlate bulk soil conductivity (EC_a) with the saturated paste extract (EC_e) as a standard. Geostatistical analysis of the spatial and temporal salinity patterns will be discussed for the fairways.