Different soils of an urban forest in New York City showed relatively low, yet similar rates of N mineralization and nitrification in laboratory potential measurements. This consistent pattern occurred even though a number of factors known to influence these processes (including overstory vegetation, soil type, and heavy metal levels) differed between the urban samples. Net N mineralization rates in forest floor and A horizon samples from a hemlock stand within the urban forest were 81% and 53% lower than respective samples from a comparable rural stand. In addition, all forest floor and A horizon samples from the urban forest were extremely hydrophobic. The low mineralization rates and hydrophobic nature of the urban samples suggested that factors associated with the ‘urban grime’ hydrocarbons may be limiting the activity of soil microbes and invertebrates. Trampling and high concentrations of heavy metals may have synergistic effects that would act to reduce net N mineralization and nitrification within the urban forest.
About This Article As :
For further details log on website: