Can Precipitation Chemistry Influence Dissolved P Losses?.

Acid rain degraded environmental quality at a continental scale until regulations on power plants decreased sulphur emissions and increased the pH of rainfall since about 2000. Over the same period, there has been increased soluble P loading to Lake Erie through the Sandusky and Maumee rivers. In this presentation, we will examine the potential link between precipitation chemistry and soluble P loading to Lake Erie. In a preliminary study, soils from the region were extracted with water that mimicked the chemistry of rainwater from 1990 and 2011. Significant increases in SP extracted from soils was greater in four of six soils when the 2011 rainwater chemistry was used compared to the 1990. Similarly, observations were made for five of six fertilizers extracted with the two mimicked rainwaters. This work does not provide conclusive evidence that rainwater chemistry is contributing to the increased soluble P loading to Lake Erie; however, these observations do suggest that there could be a link between the two and that further experimentation is warranted.