STUDY DESCRIPTION

Sandy soils (entisols) in the vicinity of orange groves on Lake Wales Ridge. - click to enlarge

     Citrus is the top agricultural crop in Florida (excluding pastureland), accounting for about 75 percent of the nation’s citrus production, and generating over $1.6 billion of revenue in Florida annually. Nearly 40% of Florida’s citrus acreage occurs on the sandy soils (Entisols) along the central Florida ridge systems.The most prominent of these ridge systems is the Lake Wales Ridge which is covered by one of the most extensive concentrations of citrus groves in the U.S.

     The Ridge was selected for study because it is highly vulnerable to leaching of chemicals such as pesticides and fertilizers. The sandy soils on the Ridge are well drained and contain little organic matter to adsorb, or effectively filter out, organic compounds. The long growing season in Florida necessitates multiple applications of fertilizers and pesticides, thereby increasing the potential for leaching of these chemicals compared to many locations in the United States. Seasonally high rainfall amounts and intensities in this region increase the potential for transport of contaminants into the subsurface. Furthermore, the ground water system in the surficial (water table) aquifer is closely linked with the numerous lakes in the region and is hydraulically connected with the underlying Upper Floridan aquifer, the primary municipal water supply for the region.

Lake Wales Ridge has been the focus of a number of efforts to minimize potential impacts of citrus agriculture on water resources. Citrus growers and industry representatives, the University of Florida Institute of Food and Agricultural Science (IFAS), and several state and federal agencies have partnered in related research and monitoring in this region. Results of this work have included the formation of collaborative industry-science working groups, as well as development of guidelines and regulations for application of specific agrichemicals to minimize potential transport into the subsurface, including the adoption of fertilizer best management practices developed specifically for Ridge citrus (State of Florida, 2002, Statute Title XXXV).

     Ground water is the principal source of water supply on Lake Wales Ridge, typical of most regions in Florida.The current study is focused on ground water in the unconfined surficial aquifer. Water-table depths in the surficial aquifer on Lake Wales Ridge

Split-spoon sample during drilling of monitoring wells typifies the uniformity of the sandy deposits on the Ridge. - click to enlarge

range from less than 5 ft to more than 130 ft below land surface.

• STUDY AREA AND NETWORK DESIGN
   
• SAMPLING HISTORY
   
• TARGET ANALYTES AND LABORATORY METHODS