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R iparian ecosystems are known to be important in the control of nonpoint source pollution and maintenance of healthy aquatic ecosystems (Lowrance et al., 1997). The Riparian Ecosystem Management Model (REMM) (Lowrance et al., In press) has been developed as a tool to aid natural resource agencies and others in making decisions regarding management of riparian buffers to control nonpoint source pollution. REMM is also intended as a tool for researchers to study the complex dynamics of hydrology and water quality functions of riparian ecosystems. The structure of REMM is consistent with buffer system specifications recommended by the U.S. Forest Service and the USDA-Natural Resources Conservation Service as national standards (NRCS, 1995; Welsch, 1991). The specified riparian buffer system consists of three zones parallel to the stream, representing increasing levels of management away from the stream (fig. 1). These zones are zone 1, a narrow, undisturbed native forest area adjacent to the stream for protecting the stream bank and aquatic environment; zone 2, an area with a managed woody vegetation for sequestering sediment and nutrients from upland runoff;

A critical step in production of winter rapeseed (Brassica napus L.) in humid environments is seed harvest. This 3‐yr study (1986 to 1989) evaluated the effect of harvesting method, harvester type, and seed color stage on seed yield of three rapeseed cultivars (‘Westar’, ‘Cascade’, and ‘Bridger’) near Tifton, GA. No consistent trends were exhibited by swathing or direct combining rapeseed. Seed yield was influenced by weather conditions and crop stage rather than harvesting methods. Both harvesting methods seem potentially acceptable for rapeseed production in the Southeastern USA; however, the added input requirements for swathing may reduce the economic potential for this practice. A draper table‐type combine significantly reduced seed yield losses when compared with an auger‐type combine. Auger‐type combines may need modification to reduce potential seed losses. Mechanical losses reduced total seed yields from 21 to 66%. The best machine‐harvested rapeseed yields were obtained in 1988–1989 with a draper table‐type harvester, either directly combining at 70 to 90% of dark seed (average yield for all cultivars of 1427 lb/acre) or swathing at 50 to 70% of dark seed (average yield of 1294 lb/acre).

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