Tuesday, November 6, 2007 - 2:00 PM
173-7

Monitoring Spatial Variability in Soil Moisture, Salinity, Hardness, and Turf Stress: Applications and Protocols.

Robert Carrow1, Van Cline2, and Joseph Krum1. (1) Crop & Soil Sciences, University of Georgia, Griffin Campus, 1109 Experiment Street, Weed Science Bld, Griffin, GA 30223-1797, (2) Toro Company, The Toro Co., 8111 Lyndale Ave. S, Minneapolis, MN 55420

Mobile spatial mapping of site conditions has potential for precision turfgrass management, especially with respect to water-use efficiency/conservation and salinity management on complex sites with a high degree of spatial and temporal variability. We have developed mobile devices compatible with GPS/GIS technology capable of rapid measurement of surface zone volumetric water content (VWC, where VWC data was used to map spatial evapotranspiration/ET patterns), turfgrass stress (NDVI, normalized differential vegetative index), penetrometer resistance (PR), and electrical conductivity of bulk soil conductivity (ECa) by soil depth. Measurement flexibility includes daily mapping during dry-down periods following irrigation or rainfall events. Six field applications and protocols involving a holistic approach to improved water-use efficiency will be discussed: 1) Initial mapping information to identify relatively easy alterations in irrigation design and/or scheduling for uniformity; 2) Evaluation of system design for degree of uniformity to determine if the system is efficient or requires replacement; 3) Audit of a newly installed system with respect to adequate design for uniformity and as a tool to help turf managers maximize the use of their new system;. 4) Defining site-specific management units (SSMU) on saline and non-saline sites; 5) Determination of the best location for placement of in-situ sensor arrays to truly represent SSMU areas; and 6) For salt-affected sites, the use of these technologies for monitoring salinity spatial and temporal changes for salt management – where to leach, how much water to apply, is leaching effective. Combining systematic protocols for each of these applications can provide a more precise and robust water auditing approach and a holistic approach to water-use efficiency on complex turfgrass sites.