ECONOMIC AND ENVIRONMENTAL BENEFITS OF MANDATED AGRICULTURE BEST MANAGEMENTPRACTICES

摘要

Farmers receive income from many things they produce in abundance -- food, feed, fiber and fuel. Farmersalso may generate environmental benefits (improved water quality and fisheries and wildlife habitat) by managing theiroperations in certain ways. Unfortunately, farmers have limited ability to quantify the environmental benefits associated withland use practices. Furthermore, farmers may reduce their income from working lands to produce positive externalities. Thisresearch used a computer simulation model to examine the relationship between agricultural practices, water quality (nutrientand sediment loss), fish communities and net farm income within two small watersheds -- a coolwater stream and awarmwater stream. We used the Agricultural Drainage and Pesticide Transport (ADAPT) model in relation to land use tocalculate in-stream suspended sediment concentrations using estimates of sediment delivery, runoff, baseflow and streambank erosion, and quantified the effects of suspended sediment exposure on fish communities. When the agriculture BestManagement Practices (BMPs) we examined were simulated, net farm income remained relatively unchanged in bothwatersheds, relative to current conditions. We found a decrease in “lethal” concentrations of suspended sediment on fish inthe coolwater watershed with an increase in conservation tillage, riparian buffers, and permanent vegetative cover. However,land use change in the warmwater watershed did not significantly decrease the effects of suspended sediment on the fishcommunity. This difference between watersheds is likely due to differential tolerance to suspended sediment betweencoolwater and warmwater fish communities and differences in topography, runoff and bank erosion between the two streams.