Water Resources Research Act Program

Details for Project ID 2018CT317B

Nitrogen and Phosphorus Leaching from Compost-Amended Lawns

Institute: Connecticut
Year Established: 2018 Start Date: 2018-03-01 End Date: 2020-02-29
Total Federal Funds: $25,000 Total Non-Federal Funds: $52,443

Principal Investigators: Karl Guillard, Thomas Morris

Project Summary: Nitrogen and Phosphorus Leaching from Compost-Amended Lawns Organic management of lawns has become one of the fastest growing segments of the lawncare and landscape industry. This has been spurred, in part, from concerns about synthetic fertilizers and pesticides on environmental quality and human health. Many believe that organic amendments pose little or no threat to the environment compared to synthetic chemical applications. Although N fertilization to lawns is not yet regulated in Connecticut, new laws regulate the application of fertilizer P to lawns. However, composts and other organic amendments have been exempt from the P regulations if they contain 0.67% or less phosphate (P2O5). This exemption has further strengthened the perception that organic fertilizers or composts are not harmful to the environment. Previous research in Connecticut has documented N leaching losses from turfgrass receiving organic fertilizers, and current research in Connecticut suggests that fertilizer contributes more to the embayment Nloads in Long Island Sound than has been reported in previous estimates. Recent research has reported P leaching at concentrations that can cause eutrophication occurring in soils that have exceeded their P saturation index, or when extractable soil test P concentrations exceed the environmental critical level. There are little or no data about N and P leaching from compost-amended lawns. Therefore, the objectives of this proposal are to determine N and P leaching from lawn turf receiving varying compost application rates. Zero-tension soil monolith lysimeters will collect percolate from lawn turf that will be analyzed for concentrations of various forms of N and P. Flow-weighted concentrations and mass loss of N and P will be determined and correlated to soil test P and labile-N concentrations. These relationships will help guide compost or organic fertilizer recommendations for lawns to minimize leaching losses of N and P to shallow groundwater.