Production and application of manure nitrogen and phosphorus in the United States since 1860

Abstract. Livestock manure, as a recyclable source for nitrogen (N) and phosphorus (P) in the Soil-Plant-Animal system, plays an important role in nutrient cycling. Given the agricultural benefits and environmental pollutants brought by manure, it is of great importance to estimate the spatial variations and temporal trajectories of manure production and its application in croplands of the contiguous United States (U.S.). Here, we developed datasets of annual animal manure N and P production and application in the contiguous U.S. at a 30 arc-second resolution over the period of 1860–2017. The total production of manure N and P increased from 1.4 Tg N yr−1 and 0.3 Tg P yr−1 in 1860 to 7.4 Tg N yr−1 and 2.3 Tg P yr−1 in 2017. The increasing manure nutrient production was associated with increased livestock numbers before the 1980s and enhanced livestock weights after the 1980s. The high-nutrient region mainly enlarged from the Midwest toward the Southern U.S., and became more concentrated in numerous hot spots after the 1980s. The South Atlantic-Gulf and Mid-Atlantic basins were the two critical coastal regions with high environmental risks due to the enrichment of manure nutrient production and application from the 1970s to 2010s. Our long-term manure N and P datasets provide critical information for national and regional assessments of nutrient budgets. Additionally, the datasets can serve as the input data for ecosystem and hydrological models to examine biogeochemical cycles in terrestrial and aquatic ecosystems. Datasets are available at https://doi.org/10.1594/PANGAEA.919937 (Bian et al., 2020).