water quality loadings (nitrogen and phosphorous) from SWAT simulations on different crop expansion scenarios. This dataset is associated with the following publication: Chen, P., Y. Yuan, W. Li, S. LeDuc, T. Lark, X. Zhang, and C. Clark. Assessing the Impacts of Recent Crop Expansion on Water Quality in the Missouri River Basin Using the Soil and Water Assessment Tool. Journal of Advances in Modeling Earth Systems. John Wiley & Sons, Inc., Hoboken, NJ, USA, 13(6): e2020MS002284, (2021).

This dataset consists of input and output datasets for estimating trends in river loads using the Weighted Regressions on Time Season and Discharge (WRTDS) model. The input datasets includes a discharge datafile and concentration datafiles for 6 water quality constituents: Total Phosphorus, Total Nitrogen, Nitrate plus Nitrite, Ammonium, Orthophosphate and Suspended Sediment. The period of record for the water quality data is from 1975 to 2017. The concentration and discharge data are for one site, the Mississippi River Outflow site, which is based on concentration data from USGS site 07373420, Mississippi River near St. Francisville, LA, and the discharge data are the sum of US Army Corps of Engineers Sites 01100 (Tarbert Landing) and 02600 (Old River Outflow) . Output dataset has the annual WRTDS estimates for time period 1975 to 2017 for all six constituents.

This dataset consists of input and output datasets for estimating trends in river loads using the Weighted Regressions on Time Season and Discharge (WRTDS) model. The input datasets includes a discharge datafile and concentration datafiles for 6 water quality constituents: Total Phosphorus, Total Nitrogen, Nitrate plus Nitrite, Ammonium, Orthophosphate and Suspended Sediment. The period of record for the water quality data is from 1975 to 2017. The concentration and discharge data are for one site, the Mississippi River Outflow site, which is based on concentration data from USGS site 07373420, Mississippi River near St. Francisville, LA, and the discharge data are the sum of US Army Corps of Engineers Sites 01100 (Tarbert Landing) and 02600 (Old River Outflow) . Output dataset has the annual WRTDS estimates for time period 1975 to 2017 for all six constituents.

This dataset consists of input and output datasets for estimating trends in river loads using the Weighted Regressions on Time Season and Discharge (WRTDS) model. The input datasets includes a discharge datafile and concentration datafiles for 6 water quality constituents: Total Phosphorus, Total Nitrogen, Nitrate plus Nitrite, Ammonium, Orthophosphate and Suspended Sediment. The period of record for the water quality data is from 1975 to 2017. The concentration and discharge data are for one site, the Mississippi River Outflow site, which is based on concentration data from USGS site 07373420, Mississippi River near St. Francisville, LA, and the discharge data are the sum of US Army Corps of Engineers Sites 01100 (Tarbert Landing) and 02600 (Old River Outflow) . Output dataset has the annual WRTDS estimates for time period 1975 to 2017 for all six constituents.

This dataset consists of input and output datasets for estimating trends in river loads using the Weighted Regressions on Time Season and Discharge (WRTDS) model. The input datasets includes a discharge datafile and concentration datafiles for 6 water quality constituents: Total Phosphorus, Total Nitrogen, Nitrate plus Nitrite, Ammonium, Orthophosphate and Suspended Sediment. The period of record for the water quality data is from 1975 to 2017. The concentration and discharge data are for one site, the Mississippi River Outflow site, which is based on concentration data from USGS site 07373420, Mississippi River near St. Francisville, LA, and the discharge data are the sum of US Army Corps of Engineers Sites 01100 (Tarbert Landing) and 02600 (Old River Outflow) . Output dataset has the annual WRTDS estimates for time period 1975 to 2017 for all six constituents.

This dataset consists of input and output datasets for estimating trends in river loads using the Weighted Regressions on Time Season and Discharge (WRTDS) model. The input datasets includes a discharge datafile and concentration datafiles for 6 water quality constituents: Total Phosphorus, Total Nitrogen, Nitrate plus Nitrite, Ammonium, Orthophosphate and Suspended Sediment. The period of record for the water quality data is from 1975 to 2017. The concentration and discharge data are for one site, the Mississippi River Outflow site, which is based on concentration data from USGS site 07373420, Mississippi River near St. Francisville, LA, and the discharge data are the sum of US Army Corps of Engineers Sites 01100 (Tarbert Landing) and 02600 (Old River Outflow) . Output dataset has the annual WRTDS estimates for time period 1975 to 2017 for all six constituents.

This dataset consists of input and output datasets for estimating trends in river loads using the Weighted Regressions on Time Season and Discharge (WRTDS) model. The input datasets includes a discharge datafile and concentration datafiles for 6 water quality constituents: Total Phosphorus, Total Nitrogen, Nitrate plus Nitrite, Ammonium, Orthophosphate and Suspended Sediment. The period of record for the water quality data is from 1975 to 2017. The concentration and discharge data are for one site, the Mississippi River Outflow site, which is based on concentration data from USGS site 07373420, Mississippi River near St. Francisville, LA, and the discharge data are the sum of US Army Corps of Engineers Sites 01100 (Tarbert Landing) and 02600 (Old River Outflow) . Output dataset has the annual WRTDS estimates for time period 1975 to 2017 for all six constituents.

Nitrogen and phosphorus losses from agricultural areas have impacted the water quality of downstream rivers, lakes, and oceans. As a result, investment in the adoption of agricultural best management practices (BMPs) has grown but assessments of their effectiveness at large spatial scales have been sparse. This study applies regional Spatially Referenced Regression On Watershed-attributes (SPARROW) models developed for the Midwest, Northeast, and Southeast regions of the United States to quantify regional effects of BMPs on nutrient losses from agricultural lands. These models were used because they account for specific BMPs in the prediction of instream nutrient loads. This data release accompanies the journal article "Quantifying regional effects of best management practices on nutrient losses from agricultural lands" (https:// doi:10.5066/pending), and it contains the input and output data for the modeling scenarios that were evaluated relative to the 2012 regional SPARROW models.

Nitrogen and phosphorus losses from agricultural areas have impacted the water quality of downstream rivers, lakes, and oceans. As a result, investment in the adoption of agricultural best management practices (BMPs) has grown but assessments of their effectiveness at large spatial scales have been sparse. This study applies regional Spatially Referenced Regression On Watershed-attributes (SPARROW) models developed for the Midwest, Northeast, and Southeast regions of the United States to quantify regional effects of BMPs on nutrient losses from agricultural lands. These models were used because they account for specific BMPs in the prediction of instream nutrient loads. This data release accompanies the journal article "Quantifying regional effects of best management practices on nutrient losses from agricultural lands" (https:// doi:10.5066/pending), and it contains the input and output data for the modeling scenarios that were evaluated relative to the 2012 regional SPARROW models.

This dataset consists of input and output datasets for estimating nitrogen (N) and phosphorus (P) balances for the Mississippi River Basin from 1950 to 2017. The N balance was calculated as the difference between inputs (fertilizer, manure, wastewater treatment facility effluent, N fixation, and atmospheric deposition) and outputs (crop uptake and removal in harvest and gaseous emissions to the atmosphere). The P balance was calculated as the difference between inputs (fertilizer, manure, wastewater treatment facility effluent, and weathering) minus outputs (specifically, P harvested and removed in crops, hay, and pasture).