This data set contains county-level estimates of nitrogen and phosphorus from fertilizer, for both farm and nonfarm uses, for the conterminous United States, for 1987 through 2006. State-level farm and nonfarm nitrogen and phosphorus were derived from the Association of American Plant Food Control Officials (AAPFCO) commercial fertilizer sales data. State estimates were then allocated to the county-level using fertilizer expenditure as county weights for farm fertilizer, and population density as county weights for nonfarm fertilizer.

This data set contains county-level estimates of nitrogen and phosphorus from fertilizer, for both farm and nonfarm uses, for the conterminous United States, for 1987 through 2006. State-level farm and nonfarm nitrogen and phosphorus were derived from the Association of American Plant Food Control Officials (AAPFCO) commercial fertilizer sales data. State estimates were then allocated to the county-level using fertilizer expenditure as county weights for farm fertilizer, and population density as county weights for nonfarm fertilizer.

This data set contains county-level estimates of nitrogen and phosphorus from fertilizer, for both farm and nonfarm uses, for the conterminous United States, for 1987 through 2012. State-level farm and nonfarm nitrogen and phosphorus were derived from the Association of American Plant Food Control Officials (AAPFCO) commercial fertilizer sales data. State estimates were then allocated to the county-level using fertilizer expenditure from the Census of Agriculture as county weights for farm fertilizer, and effective population density as county weights for nonfarm fertilizer. Data computations for 2007 - 2012 estimates are results of methods applied directly from Gronberg and Spahr, 2012. Data for 1987 - 2006 are exactly those published in Gronberg and Spahr, 2012.

This data set contains county-level estimates of nitrogen and phosphorus from fertilizer, for both farm and nonfarm uses, for the conterminous United States, for 1987 through 2012. State-level farm and nonfarm nitrogen and phosphorus were derived from the Association of American Plant Food Control Officials (AAPFCO) commercial fertilizer sales data. State estimates were then allocated to the county-level using fertilizer expenditure from the Census of Agriculture as county weights for farm fertilizer, and effective population density as county weights for nonfarm fertilizer. Data computations for 2007 - 2012 estimates are results of methods applied directly from Gronberg and Spahr, 2012. Data for 1987 - 2006 are exactly those published in Gronberg and Spahr, 2012.

This data set consists of county estimates of nitrogen and phosphorus in kilograms from animal manure in the conterminous United States for 2002. These estimates were based on county-level population data of livestock, poultry, and other animals (cattle, poultry, hogs and pigs, horses and ponies, sheep and lambs) from the 2002 Census of Agriculture (2004) using methods described in Ruddy and others (2006).

This data set consists of county estimates of nitrogen and phosphorus in kilograms from animal manure in the conterminous United States for 2002. These estimates were based on county-level population data of livestock, poultry, and other animals (cattle, poultry, hogs and pigs, horses and ponies, sheep and lambs) from the 2002 Census of Agriculture (2004) using methods described in Ruddy and others (2006).

This product provides tabular estimates of kilograms of nitrogen and phosphorus from a) fertilizer, and b) manure, for counties in the conterminous United States for the period 1950-2017. Data are generated for approximate five-year periods over the time, coinciding with U.S. Department of Agriculture Census of Agriculture census years. This data release also includes a model archive suitable for recreating the 2017 fertilizer estimates.

This product provides tabular estimates of kilograms of nitrogen and phosphorus from a) fertilizer, and b) manure, for counties in the conterminous United States for the period 1950-2017. Data are generated for approximate five-year periods over the time, coinciding with U.S. Department of Agriculture Census of Agriculture census years. This data release also includes a model archive suitable for recreating the 2017 fertilizer estimates.

This dataset contains catchment-level estimates of nitrogen and phosphorus fertilizer use, for agricultural lands, for the conterminous U.S., for 2012. An approach was developed to relate farm commercial fertilizer sales data from the Association of American Plant Food Control Officials (AAPFCO) to a set of explanatory variables using spatially-referenced modeling methods. Separate models for nitrogen and phosphorus are developed to estimate elemental fertilizer use on agricultural lands for the conterminous U.S. at the National Hydrography Dataset Plus version 2 (NHDPlusV2) catchment scale. The approach builds on earlier efforts that use Association of American Plant Food Control Officials (AAPFCO) data on fertilizer sales to provide county-level estimates of nitrogen and phosphorus fertilizer use. The spatially-referenced method improves on these efforts by allowing for varying nitrogen to phosphorus (NP) ratios at the catchment scale and expanding the set of variables used to allocate county-level sales data to the catchment scale. The models include catchment-level factors that are either primary determinants of fertilizer use, such as the acreage of different crop types, or measures reflecting the intensity of use, such as climate. Explanatory variables available only at the county scale, such as United States Department of Agriculture (USDA) Census of Agriculture (COA) estimates of fertilizer expenditures, are included to improve the model predictions of elemental use. The nitrogen and phosphorus models explain over 90 percent of the variation in elemental use, and the statistical approach allows for the estimation of uncertainty of predicted use in each catchment. The spatial patterns of model estimates reflect known agricultural cropping practices across the U.S. that transcends political boundaries, despite the county/state-orientation of the fertilizer sales information. The results are expected to be useful for a variety of water-quality assessments that are intended to estimate nitrogen and phosphorus loads to streams. A companion data release provides catchment/county level model input for the nitrogen and phosphorus fertilizer use models and is listed in this metadata under Cross Reference. The software and methods used for producing these estimates are described in the USGS Scientific Investigations Report listed in this metadata under Larger Work Citation.

This dataset contains catchment-level estimates of nitrogen and phosphorus fertilizer use, for agricultural lands, for the conterminous U.S., for 2012. An approach was developed to relate farm commercial fertilizer sales data from the Association of American Plant Food Control Officials (AAPFCO) to a set of explanatory variables using spatially-referenced modeling methods. Separate models for nitrogen and phosphorus are developed to estimate elemental fertilizer use on agricultural lands for the conterminous U.S. at the National Hydrography Dataset Plus version 2 (NHDPlusV2) catchment scale. The approach builds on earlier efforts that use Association of American Plant Food Control Officials (AAPFCO) data on fertilizer sales to provide county-level estimates of nitrogen and phosphorus fertilizer use. The spatially-referenced method improves on these efforts by allowing for varying nitrogen to phosphorus (NP) ratios at the catchment scale and expanding the set of variables used to allocate county-level sales data to the catchment scale. The models include catchment-level factors that are either primary determinants of fertilizer use, such as the acreage of different crop types, or measures reflecting the intensity of use, such as climate. Explanatory variables available only at the county scale, such as United States Department of Agriculture (USDA) Census of Agriculture (COA) estimates of fertilizer expenditures, are included to improve the model predictions of elemental use. The nitrogen and phosphorus models explain over 90 percent of the variation in elemental use, and the statistical approach allows for the estimation of uncertainty of predicted use in each catchment. The spatial patterns of model estimates reflect known agricultural cropping practices across the U.S. that transcends political boundaries, despite the county/state-orientation of the fertilizer sales information. The results are expected to be useful for a variety of water-quality assessments that are intended to estimate nitrogen and phosphorus loads to streams. A companion data release provides catchment/county level model input for the nitrogen and phosphorus fertilizer use models and is listed in this metadata under Cross Reference. The software and methods used for producing these estimates are described in the USGS Scientific Investigations Report listed in this metadata under Larger Work Citation.