Caryn D Ross | Search USGS

USGS2023

Maximizing the water quality benefits of wetlands in croplands

Key Takeaways Nutrient loads from croplands continue to negatively affect surface water quality, despite considerable investments in and adoption of agricultural conservation practices aimed at reducing nutrient losses. Numerous studies indicate that effective restoration and management of wetlands in and adjacent to cultivated croplands could reduce surface and subsurface nutrient loads to downstream waters. Current drainage basin-scale models do not effectively account for the local-scale processes that are important in understanding the functional variability of wetlands and their potential as conservation practices across different spatial and temporal scales. Findings presented here from a literature review and simulation modeling study help inform bottom-up field-scale modeling of nitrogen and phosphorus dynamics and improve our understanding of the capacity for wetlands to provide nutrient retention services in agricultural drainage basins to inform strategic agricultural wetland restoration

Conservation Insight↗

USGS2022

The potential of Prairie Pothole wetlands as an agricultural conservation practice: A synthesis of empirical data

Nutrient pollution causing harmful algal blooms and eutrophication is a major threat to aquatic systems. Throughout North America, agricultural activities are the largest source of excess nutrients entering these systems. Agricultural intensification has also been a driver in the historical removal of depressional wetlands, contributing to increased hydrological connectivity across watersheds, and moving more nutrient runoff into terminal waterbodies such as the Laurentian Great Lakes and Gulf of Mexico. The Prairie Pothole Region of North America (PPR) supports grassland, cropland, wetland, and riverine systems that connect to the Missouri, Mississippi, and Red River Basins. There is a need to synthesize scientific understanding to guide more targeted conservation efforts and better understand knowledge gaps. We reviewed 200 empirical studies and synthesized results from across a minimum of 9 and maximum of 43 wetland basins (depending on the variable data available). We found an average wetland removal rate of nitrate and phosphate of 53% and 68%, respectively. Literature also showed sedimentation rates to be twice as high in wetland basins situated within croplands compared to grasslands. Our synthesis enhances understanding of nutrient processing in wetlands of the PPR and highlights the need for more empirical field-based studies throughout the region.

Iowa, Minnesota, Montana, North Dakota, South Dako↗