Recent land use change in the Western Corn Belt threatens grasslands and wetlands
Recent land use change in the Western Corn Belt threatens grasslands and wetlands
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DOI：
10.1073/pnas.1215404110
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发表时间：
2013-02
期刊：
影响因子：
--
通讯作者：
C. Wright;M. Wimberly
中科院分区：
文献类型：
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作者：
C. Wright;M. Wimberly
在美国玉米带，大宗商品价格最近翻了一番，促使土地所有者将草地改为种植玉米和大豆。在这里，我们使用国家农业统计局耕地数据层的土地覆盖数据，以评估草地转换从2006年到2011年在西部玉米带（WCB）：五个州，包括北达科他州，南达科他州，内布拉斯加州，明尼苏达州和爱荷华州。我们的分析确定了草向玉米/大豆转化率较高的地区（每年1.0-5.4%）。在整个WCB，我们发现以草为主的土地覆盖面积净减少了近53万公顷。关于正在进行草地改造的土地的农艺属性，玉米/大豆生产正在扩大到具有高侵蚀风险和易受干旱影响的边缘土地。草地转换也集中在靠近湿地的地方，对草原坑洼地区的水禽繁殖构成威胁。从北达科他州和爱荷华州的长期土地覆盖趋势表明，最近的草地转换代表了土地利用的持续变化，而不是短期的作物轮作模式的变化。我们的研究结果表明，WCB正在迅速沿着增加玉米和大豆种植的途径移动。因此，实现基于多年生生物能源作物而不是玉米乙醇和大豆生物柴油的生物燃料产业的好处的机会之窗可能正在WCB关闭。
In the US Corn Belt, a recent doubling in commodity prices has created incentives for landowners to convert grassland to corn and soybean cropping. Here, we use land cover data from the National Agricultural Statistics Service Cropland Data Layer to assess grassland conversion from 2006 to 2011 in the Western Corn Belt (WCB): five states including North Dakota, South Dakota, Nebraska, Minnesota, and Iowa. Our analysis identifies areas with elevated rates of grass-to-corn/soy conversion (1.0–5.4% annually). Across the WCB, we found a net decline in grass-dominated land cover totaling nearly 530,000 ha. With respect to agronomic attributes of lands undergoing grassland conversion, corn/soy production is expanding onto marginal lands characterized by high erosion risk and vulnerability to drought. Grassland conversion is also concentrated in close proximity to wetlands, posing a threat to waterfowl breeding in the Prairie Pothole Region. Longer-term land cover trends from North Dakota and Iowa indicate that recent grassland conversion represents a persistent shift in land use rather than short-term variability in crop rotation patterns. Our results show that the WCB is rapidly moving down a pathway of increased corn and soybean cultivation. As a result, the window of opportunity for realizing the benefits of a biofuel industry based on perennial bioenergy crops, rather than corn ethanol and soy biodiesel, may be closing in the WCB.