Assessing Nitrogen Contamination Potential via Remote Sensing

Abstract

A remote sensing-based cropland layer (CDL) was included in a group of natural and anthropogenic factors to assess the potential for nitrogen contamination of groundwater in Dickey County, North Dakota. The CDL, produced by the Spatial Analysis Research Section, USDA, NASS and the Cooperative Extension Service, NDSU, was used to determine areas of cultivation, corn or potatoes, and summer fallow. ARCVIEW was used to import the CDL image of North Dakota for 1998. The image was converted to a grid and clipped to the appropriate area of assessment. Compared to natural factors, many of the anthropogenic factors are subject to considerable change over time. Consequently, land use information from one season was modified using the ARCVIEW neighborhood statistics function to provide an estimate of land use probability. Mean values were calculated for areas of 1/2 mile radius with respect to cultivation, potatoes or corn, and summer fallow. These values were used to classify areas as low, intermediate, or high probability for these types of land use. The three land use probability layers were used in combination with other factors to determine groundwater sensitivity to nitrogen contamination.