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Dredged materials are taken from Illinois waterways by the hundreds of thousands of cubic yards each year. These materials make up a composition that varies by the location of dredging but invariably contain sand and clay brought up from the bottom of rivers and lakes. These materials are amassed at three locations throughout the state. While there is wide speculation for beneficial uses, dredged materials do not currently have any definitive use. We tested the hypothesis that dredged materials could be a useful component of constructed soil by measuring the height of native prairie plants grown in one of five soil mixes in a greenhouse experiment. Plants of four species native to Illinois prairies were grown individually in a soil mix ranging from 0 to twothirds dredged material for 8 weeks. These consisted of three herbaceous dicots and one grass- each having 5 replicates. Height measurements were taken when planted, and three additional times including when harvested. Shoots were harvested, dried and weighed. Soil type significantly affected growth of three of the four species with growth peaking in mixes that included small proportions of dredged material. We conclude that dredged sand and silt can be useful components of soil for the four prairie species studied.
Morgan, Allison, "Effects of Dredged Materials on Growth of Prairie Species" (2021). Biology. 1.