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Methodology for assessing vulnerability to agricultural drought: A Nebraska case study
Abstract
Recent drought events in the United States and the magnitude of drought losses indicate the continuing vulnerability of the country to drought. Until recently, drought management in many states, including Nebraska, has been largely response oriented with little or no attention to mitigation and preparedness. In 1998, Nebraska began to revise its drought plan in order to place more emphasis on drought mitigation. One of the main aspects of drought mitigation and planning is the assessment of who and what is vulnerable and why. The main objective of this study was to develop a methodology for assessing vulnerability to agricultural drought in Nebraska. In this study, it was hypothesized that the key factors that define agricultural drought vulnerability were climate, soils, land use and access to irrigation. Climate was expressed as the probability of seasonal crop moisture deficiency. Methodology for calculating the probability of seasonal crop moisture deficiency is presented. Soil root zone available water-holding capacity was used to represent the soil factor since it differentiates soils with different abilities to buffer crops during periods of deficient moisture. USGS Land Use/Land Cover database was used to differentiate between rangeland, cropland and non-agricultural land. Methodology for identifying irrigated cropland in Nebraska through on-screen digitizing is presented. Each factor was classified, using Geographic Information Systems (GIS), for the purpose of vulnerability assessment. The framework for derivation of an agricultural drought vulnerability map was created through development of a numerical weighting scheme to evaluate the drought potential of the classes within each factor. The contribution of the factors was considered to be equal. To produce an agricultural drought vulnerability map, all the factors were combined in a GIS to determine the areal extent of combinations of classes present. Nebraska's agricultural drought vulnerability, presented in a map form, was classified in the following categories: “low”, “low-to-moderate”, “moderate” and “high” vulnerability. Results of the agricultural drought vulnerability assessment were analyzed for potential application to Nebraska's ongoing drought planning effort.
Subject Area
Geography|Agronomy|Environmental science
Recommended Citation
Wilhelmi, Olga Vitalievna, "Methodology for assessing vulnerability to agricultural drought: A Nebraska case study" (1999). ETD collection for University of Nebraska-Lincoln. AAI9951311.
https://digitalcommons.unl.edu/dissertations/AAI9951311