Wright State University DAYTON, Ohio, United States
Worldwide, ecosystems are impacted by soil degradation. The application of soil amendments to these systems is one way to relieve soil degradation. This may be particularly important for restoration projects where critical soil properties must be returned to optimal levels to support native ecosystems. Given their high soil fertility, organic matter, and water holding capacity, adding dredged sediments to degraded soils could improve restoration success. In order to understand how dredged sediments improve the potential for restoring previously farmed soils, we examined changes in plant performance and soil properties in a greenhouse experiment. We mixed ratios of agricultural soil to dredged sediments across five treatments (100:0, 30:70, 50:50, 70:30, 0:100) and replicated each treatment five times for a total of 25 experimental pots (5 mixes x 5 replicates). Each pot was planted with 1 tablespoon of a seed mix intended to be used for Midwestern prairie restorations and allowed to grow for 1 year. The number of species in each plot was assessed three times over the course of the experiment and compared using a combination of univariate and multivariate statistics. The aboveground biomass of each species and soil properties were collected after one year and compared using univariate statistics.
The number of species in each treatment significantly differed by ratio of agricultural soil to dredged sediment (P = 0.0292, F4,20 = 3.366) with the 50:50 ratio having the greatest number of species followed by the 70% dredged sediment: 30% agricultural soil and 100% dredged sediment treatments. There were no statistically significant differences between the species present in one ratio compared to another (P >0.05), suggesting each species had equal likelihood of being found in any of the treatments. This work represents an important first step in examining the potential for dredged sediments to be used in restoring natural lands. While the use of dredged sediments as an agricultural amendment in nutrient poor soils is becoming more common worldwide, its application for improving restoration projects has only recently received attention. Outcomes from this research represent important steps in filling knowledge gaps regarding the potential for dredged sediments to be used as soil amendments for restoring native ecosystems. Soil is a non-renewable resource so methods which revitalize degraded soil are pivotal for ensuring the success of restoring degraded ecosystems.