Location: Agroecosystems Management ResearchTitle: Compost improves urban soil and water quality Author
|Sauer, Patricia - Iowa Association Of Municipal Utilities|
Submitted to: Journal of Water Resource and Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/7/2017
Publication Date: 3/20/2017
Citation: Logsdon, S.D., Sauer, P.A., Shipitalo, M.J. 2017. Compost improves urban soil and water quality. Journal of Water Resource and Protection. 9(4):345-357. doi: 10.4236/jwarp.2017.94023.
Interpretive Summary: Urban construction compacts the soil which reduces water infiltration, air exchange, and root growth. This study showed that incorporating compost mixed with topsoil reduced compaction in the surface soil compared to more shallow additions of topsoil. Growing prairie grasses resulted in dense ground cover that resulted in faster infiltration of water, slower runoff, less erosion, and less loss of phosphorus. This information is important for urban planners and landowners who want to improve plant growth on urban soils that have been compacted due to construction processes.
Technical Abstract: Construction in urban zones compacts the soil, which hinders root growth and infiltration and may increase erosion, which may degrade water quality. The purpose of our study was to determine the whether planting prairie grasses and adding compost to urban soils can mitigate these concerns. We simulated construction activities by removing the topsoil, and compacting the soil by repeatedly driving over it with a tractor. Additional small treatment areas considered different compost application methods. Plots were subjected to simulated rainfall applied used overhead sprinklers at a rate of 65 or 72 mm h-1. Bulk density was significantly reduced in surface soil where compost had been added. Compost plus prairie grasses resulted in significantly faster infiltration (63 vs. 52 mm h-1), slower runoff (4 vs. 25 mm h-2), less soil loss (25 vs. 119 kg Ha-1 h-1), and reduced loss of ortho P (57 vs. 410 g Ha-1) compared to plots planted with bluegrass. A 5 to 7.5 cm thick compost blanket reduced time to runoff (60 min) compared to no compost addition (9 min). Topsoil addition without compost did not develop dark surface soil. Compost additions are recommended to reduce negative effects of urban compaction. Over time the depth of compost additions decreased, necessitating further additions.