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Monitoring Agricultural Cropping Patterns across the Laurentian Great Lakes Basin Using MODIS-NDVI Data
LUNETTA, R. S., Y. Shao, J. Ediriwickrema, AND J. G. LYON. Monitoring Agricultural Cropping Patterns across the Laurentian Great Lakes Basin Using MODIS-NDVI Data. International Journal of Applied Earth Observation and Geoinformation. Elsevier BV, AMSTERDAM, Netherlands, 12:81-88, (2010).
Ethanol production, especially corn ethanol, increased rapidly across the mid-western USA between 2005–2007 (RFA, 2007). A substantial research effort has been dedicated to study the increasing ethanol production and the potential impacts on energy balance, greenhouse-gas emissions, economics, and food security. Some researchers have suggested that corn ethanol is energy efficient (Shapouri et al., 2002; Hill et al., 2006), resulting in a net reduction in greenhouse-gas emissions (Hill et al., 2006); while many others suggested a negative energy efficiency (Pimentel and Patzek, 2005) and greenhouse-gas reduction (Searchinger et al., 2008). The debate is still ongoing relative to various assumptions, scenarios, and analytical methods. There is also concern about the competition between the ethanol corn and traditional agricultural uses. Fertile cropland is limited and the increased use of corn for ethanol production reduces the amount available for other uses and reduces the acreages planted with other crop types (Pimentel, 2003). Recently, the environmental implications for ethanol corn has received increasing attention (Pimentel et al., 2003; Pimentel and Patzek, 2005; Farrell et al., 2006; Zah et al., 2007; Scharlemann and Laurance, 2008). The research of Zah et al. (2007) suggested that corn ethanol may have greater overall environmental cost than using fossil fuels. Water quality, soil erosion, air pollution, biodiversity and the loss of natural habitats are of particular concerns at both local and regional scales (Hodge, 2002; Huston and Marland, 2003; Pimentel and Patzek, 2005; Searchinger et al., 2008).
The Moderate Resolution Imaging Spectrometer (MODIS) Normalized Difference Vegetation Index (NDVI) 16-day composite data product (MOD12Q) was used to develop annual cropland and crop-specific map products (corn, soybeans, and wheat) for the Laurentian Great Lakes Basin (GLB). The crop area distributions and changes in crop rotations were characterized by comparing annual crop map products of 2005, 2006, and 2007. The total acreages for corn and soybeans were relatively balanced for calendar years 2005 (31,462 km2 and 31,283 km,2 respectively) and 2006 (30,765 km 2 and 30,971 km2 respectively). Conversely, corn acreage increased approximately 21% from 2006 to 2007, while soybean and wheat acreage decreased approximately 9% and 21%, respectively. Two-year crop rotational change analyses were conducted for the 2005–2006 and 2006–2007 time periods. The large increase of corn acreages in 2007 introduced crop rotation changes in the GLB. Compared to the 2005–2006 crop rotation patterns, the crop rotations for 2006–2007 resulted in increased corn-corn, soybean-corn, and wheat-corn crop rotational changes. The increases in corn acreages associated with new biofuel mandates could have potential negative impacts on nutrient loadings, pesticide exposures, and sediment-mediated habitat degradation. Increases in Canadian corn acreages in 2007 were attributed to the higher world-wide corn prices. Additional study is needed to determine the potential impacts of corn-based biofuel agricultural on watershed ecosystems and receiving waterbodies.