| Autor: |
Schilling, Keith, Streeter, Matthew, Pierce, Sophie, Brennan, Greg, St. Clair, Marty |
| Předmět: |
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| Zdroj: |
Journal of the ASABE; 2022, Vol. 65 Issue 5, p985-995, 11p |
| Abstrakt: |
Efforts to reduce nutrient export from agricultural crop production in the U.S. Midwest are leading to development of new conservation practices. In this study our objectives were to: (1) characterize subsurface soils and hydrogeology found in two main drainageway areas in eastern Iowa, (2) compare groundwater quality to upland agricultural fields, and (3) utilize a groundwater flow model to assess the capacity of drainageways to provide additional NO3-N processing in agricultural watersheds. Using data obtained from a network of 12 shallow wells installed across six different waterways, we found that the waterways contained fine-textured and nutrient rich alluvial soils derived from erosion and deposition of upland loess and till. Concentrations of NO3-N in waterway groundwater (3.1 mg/l) were 70% lower compared to ground- water beneath nearby cropped fields (10.5 mg/l). A shallow water table in the organic-rich drainageway soils provides the requisite organic carbon, anaerobic soil conditions, and nitrogen supply for denitrification to occur. Numerical modeling suggested that groundwater from the surrounding catchment discharges approximately 53 m³/day into the waterways and reduces NO3-Nmass by 144.3 kg/yr, or 7.8 kg/ha. Results suggest that drainageways could be better exploited for additional NO3-N reductions from subsurface drainage if the flow could be diverted into these areas. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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