Particulate organic matter and soil nitrogen availability in urban landscapes

Toward developing nitrogen management in amenity tree care, we studied soil organic matter, microbial biomass, and carbon and nitrogen mineralization in an attempt to characterize the plant available nitrogen under a variety of landscape management conditions. Fine particulate organic matter (POM) fractions were significantly correlated with microbial biomass, carbon mineralization, and nitrogen mineralization (R2 values ranging from 0.42 to 0.89). These urban landscapes were assigned a site quality index based on landscape age and management practices. Fine POM, microbial biomass N, and N mineralization were significantly and positively correlated with the site quality index (R2 values of 0.86, 0.90, and 0.84, respectively). We propose that with refinement and further testing, a fine POM measurement can be used to accurately predict soil nitrogen availability in urban landscapes. This research shows that urban landscapes are quite variable in terms of nitrogen availability. As a result of this variability, we recommend that urban landscapes be assessed on a per-site basis for proper nitrogen management.

32, 4, 180-191
Arboriculture & Urban Forestry (published by)