You are here:
Effectiveness of Nutrient Management for Reducing Phosphorus Losses from Agricultural Areas
Citation:
Kamrath, B. AND Y. Yuan. Effectiveness of Nutrient Management for Reducing Phosphorus Losses from Agricultural Areas. 2023 ASABE Annual International Meeting, Omaha, NE, July 09 - 12, 2023.
Impact/Purpose:
Water bodies and coastal areas around the world are threatened by excessive amounts of nitrogen (N) and phosphorous (P) from upstream watersheds, which can cause rapid proliferation of algae. These algal blooms negatively impact drinking water sources, aquatic species, and recreational services of water bodies by producing toxins, also called harmful algal blooms (HABs). Finding ways reducing nutrient losses from agricultural fields is paramount important for EPA program offices and regional partners to make informed decisions to better control nutrient losses from agricultural fields.
Description:
Dissolved reactive phosphorus (DRP) export from agricultural areas is a leading cause of nutrient pollution in freshwater systems (e.g., the North American Great Lakes). A potential solution to mitigate the excessive release of DRP is the use of nutrient management practices. To evaluate the effectiveness of nutrient management practices, as described in NRCS Code 590, we conducted a literature review to synthesize P management and DRP export data from peer-reviewed articles published between 2000 to 2022. We identified 29 potential publications and extracted 155 and 96 observations from plot- and field-scale studies, respectively. DRP concentrations and loads had a positive relationship with phosphorus (P) fertilizer rate although the relationship is not strong at the plot-scale. In addition, our results suggested that DRP losses had a greater increase as P fertilization rate increased to a higher rate. In terms of application method, subsurface placement greatly reduced acute DRP losses relative to surface placement (e.g., broadcasting). As for fertilizer source, inorganic fertilizers produced greater DRP losses relative to organic fertilizers. Statistical analysis indicated that the impacts of both application method and fertilizer source were influenced by P fertilizer rate. Furthermore, in agricultural soils with high soil test P, high DRP concentrations were observed even when moderate or high fertilizer rates were used. Unlike the plot-scale results, field-scale data were generally inconclusive, likely due to variability in spatial scale, monitoring times, soil P, and maximum application rates. At the plot-scale, our results highlight adverse impacts of overfertilization and the surface application of P fertilizers, while the overall results highlight the need for further research into the influence of nutrient management on P losses, especially at the field scale.
