Speed Bumps in the Nugis Adventure.

IPNI’s NuGIS project set out to solve a simple equation, nutrient input minus removal equals balance. We felt there was a need to systematically and rigorously provide this information over time and space due to its relevance to several contemporary production and environmental issues. The objective was to calculate balance at the county and watershed levels over time for the agricultural lands of the USA. The quest for data to feed the equation proved to be a challenge. IPNI collected data from a variety of sources including the Census of Agriculture, USDA-NASS, and the Association of American Plant Food Control Officials (AAPFCO). Each data source presented issues. None of the data sources provided the exact numbers needed. We had to coax needed information out of the data sets available. The project had to overcome inconsistences in the data structure over time, missing or undisclosed data, and variability in the spatial coverage provided. Solving the equation required development of methods for using surrogate data to calculate or fill in missing data. Procedures were needed for repurposing data: e.g. AAPFCO provides fertilizer sales data and we needed fertilizer use data. Sales data do not always reflect the county in which the product was used. Inconsistencies in how farm and non-farm fertilizer sales were reported also had to be overcome. Each data source provided data that required some degree of adjustment to be suitable for use in the equation. The result is a national, county-level dataset that estimates nutrient balances over time. It looks orderly and seems straightforward. But the path to generating this dataset was full of detours, pocked with speed bumps and far from straight.