Homeowner Survey Responses and Yard Soil Biogeochemistry within the Long Island Sound Watershed

The immediate watershed of the Long Island Sound (LIS) is largely composed of car-centric suburban landscapes, with extensive areas of altered, sealed, and even some polluted soils. In such suburban contexts, the lawn represents a particular kind of widespread landscape regime with considerable ecologic influence. Though varying in both size and degree of landscaping, suburban homes generally have yards, often with areas of maintained turfgrass lawn. With concern for eutrophication and hypoxic conditions within the LIS due to excess nutrient input possibly from yards, residents within the LIS watershed were surveyed regarding yard and LIS related practices and perspectives. Eighty-nine of these respondents were randomly selected to collect ecological data from their yards during spring, summer, and fall of 2021. Soil cores were collected in spring and summer, with two random 10 cm depth soil samples from both front and back yards when possible. Soil moisture, pH, nitrate, and ammonium content were determined at the Advanced Science Research Center in New York, NY. Survey data was combined with the collected biophysical data for further interdisciplinary analysis.

Average soil ammonium content was found to notably decrease with even one application of fertilizer per year (3.4 g N/kg dry soil to 1.01 kg N/kg dry soil). Average soil nitrate was found to increase with each repeated fertilization event per year (36.56 g N/kg dry soil with zero reported annual applications on one end to 66.22 g N/kg dry soil with five annual applications on the other end). Respondents who said they had increased their fertilizer compared with five years ago had the highest average soil nitrate content (59.43 g N/kg dry soil) and lowest average soil ammonium content (0.45 g N/kg dry soil) amongst all respondents. People who didn’t report using fertilizer had the lowest average soil nitrate content (36.16 g N/kg dry soil) and the highest average soil ammonium content (4.05 g N/kg dry soil). People that reported hiring a professional to fertilize their yard (but not fertilizing it themselves) had the highest average soil moisture content (19.97%), soil nitrate content (56.5 g N/kg dry soil), and pH among respondents (6.21). People that identified as highly aware about recommendations on the use of fertilizer had the highest average soil nitrate content (48.16 g N/kg dry soil), and also the lowest average soil ammonium content among respondents (1.32 g N/kg dry soil).

These results demonstrate the impact that yard fertilization practice has on soil chemistry. Most significantly, reported increases in fertilization show increases soil nitrate content, but with corresponding decreases in soil ammonium content. Furthermore, increasing education and outreach around yard fertilization may not inherently decrease yard fertilization, as perhaps individuals who engage with materials related to fertilization recommendations are more likely to even apply fertilizer. Both reported awareness of recommended practices and utilizing a professional for fertilization were associated with higher soil nitrate content. Homeowner yard contexts remain significant with direct influence on the nutrient content of the soils of the LIS watershed.