Storm events disproportionately mobilize dissolved phosphorus (P) compared to nitrogen (N), contributing to reduction in load N:P. In agricultural watersheds, conservation tillage may lead to even further declines in load N:P due to dissolved P accumulation in the top soil layers. Due to an increase in this management activity, we were interested in the impacts of conservation tillage on N and P loads during storm events. Using a 20 year data set of nutrient loads to a hypereutrophic reservoir, we observed disproportionately increasing P loads relative to base flow during storm events, whereas N loads were proportional to discharge. We also observed a change in that relationship, i.e., even greater P load relative to base flow with more conservation tillage in the watershed. This suggests conservation tillage may contribute to significantly reduced N:P loads during storms with potential implications for the water quality of receiving water bodies.
|Original language||English (US)|
|Number of pages||9|
|Journal||Environmental Science and Technology|
|State||Published - May 21 2019|
Bibliographical noteFunding Information:
This research was supported mainly by National Science Foundation awards 9318452, 9726877, 0235755, 0743192, and 1255159. Additional support was provided by the Miami Valley Resource Conservation and Development District.
© 2019 American Chemical Society.