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英文文献：Encouraging Farmers To Produce Environmental Benefits From Agriculture-鼓励农民从农业中创造环境效益
英文文献作者：Westra, John V.,Zimmerman, Julie K.H.,Vondracek, Bruce
英文文献摘要：
Farmers produce many things in abundance for which they receive income, including food, feed, fiber and fuel. Similarly, farmers generate environmental benefits such as improved water quality by reducing soil and nutrient loss and improved wildlife habitat by managing their operation in certain ways. Unfortunately, most farmers receive limited or no compensation for these positive externalities they produce. If we wish to encourage more of these positive externalities, policies need to be established and implemented that compensate producers for the benefits society receives from specific farming practices. This research examined how production practices that provide environmental benefits would affect water quality (nutrient and sediment loss), fisheries populations, and farm income in two distinct study areas in Minnesota. We developed a computer simulation model to examine the relationship between agricultural practices, water quality, fish communities, and net farm income within two small watersheds. Our analyses focused on a coolwater stream, the Wells Creek watershed in southeastern Minnesota, and a warmwater stream, a sub-watershed of the Chippewa River in western Minnesota. We used the Agricultural Drainage and Pesticide Transport (ADAPT) model in relation to land use to calculate in-stream suspended sediment concentrations using estimates of sediment delivery, runoff, baseflow and stream bank erosion, and quantified the effects of suspended sediment exposure on fish communities. Our focus was to estimate how agricultural Best Management Practices (BMPs ? conservation tillage and nutrient management implemented on all cropland, and 100 foot grass buffers along streams) would affect stream fish communities and net farm income, with reference to current conditions. We found a decrease in "lethal" concentrations of suspended sediment on fish in Wells Creek watershed with an increase in conservation tillage, riparian buffers, and permanent vegetative cover. However, land use change in the Chippewa River watershed did not significantly decrease the effects of suspended sediment on the fish community. This difference between watersheds is likely due to differential tolerance to suspended sediment between coolwater and warmwater fish communities and differences in topography, runoff and bank erosion between the two streams.
农民们大量生产各种物品以获得收入，包括食物、饲料、纤维和燃料。同样，农民也产生了环境效益，例如通过减少土壤和养分流失改善了水质，通过以某种方式管理野生动物的活动改善了它们的生境。不幸的是，大多数农民对他们生产的这些正外部性得到的补偿有限或没有。如果我们希望鼓励更多的这种正面外部性，就需要制定和实施政策，为社会从特定农业做法中获得的利益对生产者进行补偿。这项研究在明尼苏达州两个不同的研究区域考察了提供环境效益的生产做法如何影响水质(营养物质和沉积物损失)、渔业数量和农业收入。我们开发了一个计算机模拟模型来研究两个小流域内的农业实践、水质、鱼类群落和农场净收入之间的关系。我们的分析集中在一条冷水流，即位于明尼苏达州东南部的威尔斯河流域，和一条暖水流，即位于明尼苏达州西部的奇佩瓦河的一个次流域。我们使用与土地利用相关的农业排水和农药运输(ADAPT)模型，通过估算输沙量、径流、底流和河岸侵蚀来计算河流内悬沙浓度，并量化悬沙暴露对鱼类群落的影响。我们的重点是评估农业最佳管理实践(BMPs ?在所有农田实施保护性耕作和养分管理，以及沿溪流100英尺的草地缓冲区)，将会影响到溪流鱼类群落和农场净收入。我们发现，随着保护性耕作、河岸缓冲和永久植被覆盖的增加，对井溪流域鱼类的悬浮泥沙“致死”浓度下降。然而，奇佩瓦河流域的土地利用变化并没有显著减少悬沙对鱼类群落的影响。分水岭之间的这种差异可能是由于冷水和暖水鱼类群落对悬浮沉积物的耐受性不同，以及两种河流在地形、径流和河岸侵蚀方面的差异。
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