Patterns and Trends of Soil Climate Regimes and Drought Events in the Northern Great Plains

Drought is the dominant process of crop loss nationally and within Nebraska. Nearly twothirds of the 18.6 million harvested acres are covered by crop insurance (USDA/RMA, 2003; USDA/NASS, 2003). For the most part, Nebraska’s crop losses range from $50 to 75 million in non-drought years, but the losses approach nearly $200 million in drought years, such as 2000. The past growing season (2002) crop losses are projected to greatly exceed $375 million in Nebraska and more than $4 billion nationally (USDA/RMA, 2003). The analysis and understanding of drought processes in the Great Plains is an important component to developing drought mitigation strategies and reducing agricultural risks on the landscape. In building a drought decision support system for Nebraska, we have proposed a suite of drought indices linked to geospatial databases describing the agricultural statistics or infrastructure to identify drought regions and potential impacts. Most approaches to visualizing drought indices, such as the traditional Palmer Drought Severity Index (PDSI; Palmer, 1965), Standardized Precipitation Index (SPI; McKee et al., 1993; 1995), and the Drought Monitor (Svoboda et al., 2002) are small-scale maps that provide a regional (climate divisions) or national perspective, emphasizing current conditions. Most mapping approaches do not integrate thematic overlays of the agricultural infrastructure or provide the historical context, relative to agroecosystems, cropping systems, or the potential economic liabilities. In our research, we are describing the geography of agriculture, its vulnerabilities, and the drought characteristics at multiple temporal and spatial scales to enhance the understanding of drought risks.