Regional Variation in Net Anthropogenic N and P Inputs (NANI/NAPI) Across the US: 1987-2017
Abstract
The NANI/NAPI toolbox, now in its fourth version, was developed to facilitate calculation of net anthropogenic nitrogen and phosphorus inputs (NANI/NAPI) from publicly available data sources, including county-level US census and agricultural census data. The datasets have been used successfully, together with climate data, to estimate riverine N and P fluxes in the US, Europe and Asia. NANI comprises four terms: mineral fertilizer inputs, atmospheric N deposition, agricultural N fixation and net food/feed inputs to a region, calculated as the balance between local crop production and livestock and human food demand. NAPI includes the fertilizer and net food/feed input terms. Here we present updates of these estimates incorporating data from the 2017 US agricultural census and other recent datasets showing patterns of variation across the continental US. Strong regional variations can be seen, depending on the balance of crop production, livestock production, and human population density, with significant implications for the biogeochemistry of riverine and coastal waters. NANI/NAPI are dominated by fertilizer inputs in some of the large agricultural regions of the country, but livestock nutrient demands and corresponding manure availability also have major regional impacts. In urban centers, NANI/NAPI are dominated by net food inputs with implications for local sewage loads. Changes in US agriculture over the three decades are evident, including the increasing dominance of heavily fertilized crops and intensive livestock production. Variation in the relative proportions of NANI:NAPI have potentially significant implications for the Nations water quality.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFM.B45L1766S