Evidence for increased monoculture cropping in the Central United States
Evidence for increased monoculture cropping in the Central United States
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DOI：
10.1016/j.agee.2012.11.011
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发表时间：
2013-01
期刊：
影响因子：
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通讯作者：
James Plourde;B. Pijanowski;B. Pekin
中科院分区：
文献类型：
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作者：
James Plourde;B. Pijanowski;B. Pekin
虽然作物轮作模式可能很复杂，几年内轮作多种作物，但美国中部最常见的轮作做法是玉米和大豆之间的两年轮作。我们分析了2003年至2010年的作物轮作模式的变化，使用农田数据层（CDL），它提供了遥感土地覆盖层的农业作物在美国中部。CDL的准确性通过比较CDL中存在的州或县的总面积与国家农业统计局提供的总种植面积来验证。将数据层合并为2003-2006年和2007-2010年两个时间段，并确定研究区域每个地点的具体旋转模式。这些组合产生了独特的序列，如单、双、三和四，后者相当于在特定地点四年中出现的同一作物类别。对玉米和大豆进行了分析，以确定用于生产的面积以及独特作物轮作序列之间的变化量。虽然在我们研究期间的后半期，主要作物的总生产面积仅略有增加，但主要作物（例如，玉米和大豆）在连续种植序列中的生长显著增加。例如，在第一时间段受玉米影响的土地数量在第二时间段仅增加了2%。然而，从我们研究期间的前半段到后半段，四倍序列种植的玉米数量翻了一番。我们的结论是，虽然作物轮作模式是非常复杂的，在这一地区，涉及相当数量的非耕地，主要作物，如玉米的足迹在过去的十年中已经走向单作种植的做法。
While crop rotation patterns can be complex with multiple crops rotated over several years, the most common rotation practice in the Central United States is biannual rotation between corn and soybeans. We analyzed the changes in crop rotation patterns from 2003 to 2010 using the Cropland Data Layer (CDL), which provides remotely sensed land cover layers for agricultural crops in the Central United States. The accuracy of the CDL was validated by comparing the total acreage for a state or county present in the CDL with the total planted crop acreage available from the National Agricultural Statistics Service. The data layers were combined into two time periods 2003–2006 and 2007–2010, and specific rotation patterns were determined for every location in the study area. The combinations resulted in unique sequences such as single, double, triple and quadruple, the latter of which is equivalent to the same crop class present all four years at a particular location. Corn and soybeans were analyzed to determine the amount of area used for production as well as the amount of change between unique crop rotation sequences. While the total area under production of major crops in the second half of our study period increased only slightly, the extent to which major crops (e.g., corn and soybeans) were grown in continuous cropping sequences increased significantly. For example, the amount of land impacted by corn in the first time period increased by only 2% in the second time period. However, the amount of corn grown in quadruple sequence doubled from the first half to the second half of our study period. We conclude that, although crop rotation patterns are very complex in this region, involving considerable amount of non-cropland, the footprint of major crops such as corn have moved toward monoculture cropping practices in the last decade.