County, subregional and regional phosphorus data derived from the net anthropogenic nitrogen/phosphorus inputs (NANI/NAPI) toolbox

The data presented here represent estimates of the phosphorus content of crop production, phosphorus use efficiency (PUE) and agricultural phosphorus inputs associated with it across the contiguous United States. Net Anthropogenic Phosphorus Input (NAPI) estimates and related data are also provided. Data are presented at county, sub-regional and regional scales. Here, subregions refer to multi-county areas delineated with the goal of obtaining more uniform reporting areas than individual counties. Regions refer to the USDA Farm Resource Regions. The data are reported for 6 agricultural census years, 1987, 1992, 1997, 2002, 2007 and 2012. Estimates of the variables were derived originally from USDA agricultural census data, US population census data, and other sources, using version 3.1 of the NANI/NAPI calculator toolbox (Hong et al., 2011).


Data
A full list of the variables provided at county, subregional scales, together with a short description of the variables and their units are provided in Tables 1e3. Details on the characteristics of the regions and subregions considered are provided in Table 1 of [5], together with maps of regions ( Figure 1) and subregions (Fig. S1) in the same paper.

Experimental design, materials, and methods
Briefly, the data contained in the spreadsheets represent components of Net Anthropogenic Phosphorus Input (NAPI) and ancillary data obtained and postprocessed from these data using simple spreadsheet calculations to estimate variables used in phosphorus use efficiency estimates at county, subregional and regional scales across the continental US. They are based on agricultural production and ancillary data from the US Census of agriculture, population data from the US census, and other sources. Full details on methodology and original sources can be found in the references below [1e5].
Specifications Table   Subject area Biogeochemistry, agriculture, ecology More specific subject area Phosphorus cycling, phosphorus use efficiency, net anthropogenic phosphorus inputs (NAPI) Type of data Tables, multi-page spreadsheet How data was acquired Derived from publicly available sources, including US Census of Agriculture, US population Census, and processed using the NANI/NAPI toolbox Data format Raw Parameters for data selection County level data were typically estimated from agricultural and population census information. Data were aggregated to multi-county units to achieve better spatial uniformity, and to USDA-ERS Farm Resource Regions for regional comparison.

Parameters for data collection
Basic data are not derived from experiments, but represent county-level estimates based on government statistics typically collected at 5-year intervals Data source location Continental United States Data accessibility Data are published with this article. Source data from which these data are derived were obtained from the NANI/NAPI toolbox, Swaney, D.P., Hong Value of the data Why are these data useful? They represent county-level to regional variation of major agricultural phosphorus flows across the US over 3 decades at 5-year intervals, and are thus useful for biogeochemical, ecological or agricultural studies of local to regional variation Who can benefit from these data? The data should be useful to environmental research scientists interested in understanding agricultural impacts on the environment as well as patterns of agricultural production. Environmental managers at the federal, state and local level, as well as NGOs, may also find them useful. How can these data be used for further insights and development of experiments? These data provide information on phosphorus use efficiency, surplus/deficits, and anthropogenic P inputs useful for establishing nutrient budgets at various scales, for regional comparisons, and as baseline data against which to compare impacts of alternative management options.
The data are of sufficient resolution (county and multi-county) that they may also be useful for within-region or largewatershed studies.          Variable Name Units/ Format Description Estimated regional proportion of manure P available to cropland after noncropland pasture losses, 1992 1-fp *fg 1997 fraction Estimated regional proportion of manure P available to cropland after noncropland pasture losses, 1997 1-fp *fg 2002 fraction Estimated regional proportion of manure P available to cropland after noncropland pasture losses, 2002 1-fp *fg 2007 fraction Estimated regional proportion of manure P available to cropland after noncropland pasture losses, 2007 1-fp*fg 2012 fraction Estimated regional proportion of manure P available to cropland after noncropland pasture losses, 2012 *Indicates cropland area basis instead of total area basis. **Beef & veal, pork, poultry, lamb, eggs, milk.