Author
Smith, Douglas | |
JARVIE, H - Centre For Ecology And Hydrology | |
Harmel, Daren | |
Haney, Richard |
Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 5/4/2019 Publication Date: 7/11/2019 Publication URL: https://handle.nal.usda.gov/10113/6718818 Citation: Smith, D.R., Jarvie, H.P., Harmel, R.D., Haney, R.L. 2019. The role of field-scale management on soil and surface runoff C/N/P stoichiometry. Journal of Environmental Quality. 48(5):1543-1548. https://doi.org/10.2134/jeq2018.09.0338. DOI: https://doi.org/10.2134/jeq2018.09.0338 Interpretive Summary: Agricultural runoff water is often claimed to contribute to water quality problems. This study was conducted to evaluate the potential role of field-scale management on carbon, nitrogen, and phosphorus stoichiometry in soils and runoff water from agricultural fields. Cultivated and pasture fields at the Riesel Watersheds in central Texas were used for this analysis. All soil samples were phosphorus depleted relative to carbon and nitrogen. The majority of stormflow and baseflow runoff samples contained 9-19% nitrogen relative to carbon and phosphorus. Shifting from inorganic fertilizer application to poultry litter as a fertilizer source resulted in increasing absolute carbon, nitrogen and phosphorus concentrations in stormflow and baseflow runoff. Increasing rates of poultry litter application increased the phosphorus relative to carbon, while nitrogen remained relatively constant at roughly 9-11% in stormflow runoff from cultivated fields. This study shows a clear pattern of how land-use and management impact the ratios of carbon, nitrogen and phosphorus in stormflow and baseflow runoff. Technical Abstract: Agricultural runoff is often cited as a contributor to water quality impairment. This study was conducted to evaluate the potential role of field-scale management on carbon (C), nitrogen (N), and phosphorus (P) stoichiometry in soils and runoff from agricultural fields. Cultivated and pasture fields at the Riesel Watersheds in central Texas were used for this analysis, and nutrients were transformed to evaluate relative to the Redfield Ratio (106 C/16 P/1 P). Using the Redfield Ratio, all soil samples were P depleted relative to C and N. The majority of stormflow and baseflow runoff samples contained 9-19% Redfield N relative to C and P. Shifting from inorganic fertilizer application to poultry litter as a fertilizer source resulted in increasing absolute C, N and P concentrations in stormflow and baseflow runoff. Increasing rates of poultry litter application increased the Redfield P relative to Redfield C, while Redfield N remained relatively constant at roughly 9-11% in stormflow runoff from cultivated fields. This study shows a clear pattern of how land-use and management impact C/N/P stoichiometry in stormflow and baseflow runoff. |