The nitrogen biochemistry of vacant lots across an urban land reuse gradient
It is not known whether formerly residential vacant lots under varying reuse conditions are primarily a source or sink of nitrogen (N) pollution to surface waters. This study was conducted to determine how reuse intensity of properties increase N supply and N removal via denitrification. The effect of reuse intensity on N supply and N removal via denitrification were investigated, spanning undemolished vacant homes, turfgrass lots, and urban agriculture (UA). Land reuse intensity only affected soil properties in surficial soil horizons. Total N was 2.5x higher in UA soils than non-UA and nitrate was 2.6x higher in winter than summer. Despite higher soil N availability at UA sites, there were no obsered differences in denitrification activity between UA and non-UA sites. Although UA had similar denitrification activity and had high N availability compared to non-UA sites, UA only has moderate potential for runoff-driven N export, because nitrate concentrations were substantially lower than values typical for conventional agricultural soils.