RIPARIAN FOREST BUFFER SYSTEM RESEARCH AT THE COASTAL-PLAIN EXPERIMENT STATION, TIFTON, GA

Recent attention has focused on riparian forest buffer systems for fil tering sediment, nutrients, and pesticides entering from upslope agric ultural fields. Studies in a variety of physiographic areas have shown that concentrations of sediment and agrichemicals are reduced after p assage through a riparian forest. The mechanisms involved are both phy sical and biological, including deposition, uptake by vegetation, and loss by microbiological processes such as denitrification. Current res earch by USDA-ARS and University of Georgia scientists at Tifton, GA i s focusing on managing riparian forest buffer systems to alleviate agr icultural impacts on the environment. The underlying concept for this research is that agricultural impact on streams is best protected by a riparian forest buffer system consisting of three zones. In consecuti ve upslope order From the stream these zones are (1) a narrow band of permanent trees (5-10 m wide) immediately adjacent to the stream chann el which provides streambank stabilization, organic debris input to st reams, and shading of streams, (2) a forest management zone where maxi mum biomass production is stressed and trees can be harvested, and (3) a grass buffer strip up to 10 m wide to provide control of coarse sed iment and to spread overland flow. Several ongoing projects at Tifton, GA are focusing on using riparian forest buffer systems as filters. A forest management project is testing the effects of different managem ent practices on surface and ground water quality. This project includ es three different forest management practices: mature forest selectiv ely thinned forest, and clearcut. In a different study a natural wetla nd is being restored by planting trees. The effectiveness of this wetl and on filtering nutrients from dairy wastes which are being applied u pslope is being evaluated. At this same site, a pesticide study is bei ng conducted on the side opposite to where dairy wastes are applied. A n overland flow-riparian buffer system using swine lagoon waste is eva luating the effectiveness of different vegetative treatments and lengt hs of buffer zones on filtering of nutrients. In this study three vege tative treatments are compared: (1) 10 m grass buffer and 20 m riparia n forest (2) 20 m grass buffer and 10 m riparian forest, (3) 10 m gras s buffer and 20 m of the recommended wetland species maidencane. Waste is applied at the upper end of each plot at either a high or low rate , and then allowed to now downslope. The three zone riparian forest bu ffer system is being used for the Riparian Ecosystem Management Model (REMM). This model, which is currently under development at Tifton, GA , is a computer simulation model designed to reduce soil and water deg radation by aiding farmers and land use managers in decision making re garding how best to utilize their riparian buffer system. Both informa tion currently being collected in field studies and development of the REMM are innovative farm-level and forestry technologies to protect s oil and water resources.