Assessing the effects of lake-dredged sediments on soil health: Agricultural and environmental implications for northwestern Ohio.

Abstract

Dredging operations produce large amounts of sediments, and when open lake disposal is used, it can pose a threat to water quality. This study examined the potential to use dredged sediment as a farm soil amendment. We conducted greenhouse experiments to determine (a) the physico-chemical health of a farm soil amended with various dredged sediment ratios, (b) nutrient dynamics when the soil blends were subjected to simulated storm events, and (c) the effect of dredged sediment on soybean [Glycine max (L.) Merr.] belowground biomass and yield. The soil blends consisted of 100% farm soil, 90% farm soil to 10% dredged sediment, 80% farm soil to 20% dredged sediment, or 100% dredged sediment. After 123 d, the soybean plants were harvested, and physico-chemical analyses were conducted on the soil, soybeans, and percolated stormwater. We found that dredged sediment amendment improved soil health by increasing soil organic matter, cation exchange capacity, and Ca content and by decreasing bulk density and P concentration in a farm soil with P concentration above the agronomic recommended value. Crop biomass and yield averages increased with increasing dredged sediment ratios. Nutrient loss (P and N) in the percolated solutions from the soil blends showed no significant changes when compared to the percolated solutions in the 100% farm soil treatment, indicating no significant contribution to the export of nutrients in percolated water.