Fertilizer management approaches influence nutrient leaching from residential landscapes

Residential lawn management often includes fertilizer application to encourage healthy plant growth and support the aesthetic preferences of homeowners and communities. These inputs may negatively impact the environment by increasing nutrient export to aquatic ecosystems via surface runoff or leaching through soil into groundwater. Fertilizer management and nutrient export are of particular concern in karst areas like North-Central Florida, where the underlying karst geology leads to rapid, direct connections between surface and groundwater ecosystems. We quantified nitrogen (N) and phosphorus (P) leaching from residential landscapes in North-Central Florida. We investigated nutrient leaching from landscapes spanning a real estate gradient and across different fertility treatments (no N fertilizer, synthetic mineral fertilizer, biosolids-based organic mineral fertilizer, compost topdressing, natural areas). We measured leachate from these landscapes weekly for 1 year. All residential landscapes, including control yards that received no N fertilizer, leached >10x more nitrate than natural areas, and landscapes treated with synthetic fertilizer exhibited an >80x increase in nitrate leaching. Fertilizer treatments also appeared to alter the N leaching composition, with a greater proportion of total dissolved N leaching coming from nitrate in fertilized treatments (synthetic and organic) compared to natural, control, or compost-treated landscapes. These results show that landscape management and human actions are important drivers of nutrient leaching in residential landscapes. While all residential lawns leached more N than natural areas, less leaching was associated with certain management approaches. When implemented at larger scales, these approaches may reduce the likelihood of negative impacts of residential landscapes on regional water quality.