|کد مقاله||کد نشریه||سال انتشار||مقاله انگلیسی||ترجمه فارسی||نسخه تمام متن|
|93978||160242||2016||6 صفحه PDF||سفارش دهید||دانلود کنید|
• We measured soil nitrous oxide (N2O) emissions from the New York City Afforestation Project (NY-CAP) forest plots with varied approaches to site preparation.
• We measured similar fluxes of N2O from plots planted with trees only and plots planted with trees and shrubs (p > 0.05).
• We observed lower N2O fluxes from plots with one time amendment with compost compared to plots without compost amendment.
• Higher N2O emissions (∼0.05 ng N cm−2 h−1) from plots with no shrubs and no compost suggest that plant and microbial uptake of inorganic N in urban afforestation projects are important factors in regulating and inhibiting N2O loss from soils.
• Site preparation with shrubs and compost amendment in urban afforestation projects may tighten soil N cycling by preventing N2O losses from urban soils.
The establishment of stands of trees in previously unforested areas (afforestation) is active in cities around the world. Given the complex and often degraded state of urban soils, there is great interest in soil biological processes that support plant growth but may also produce greenhouse gases in these new forests. We measured soil to atmosphere fluxes of nitrous oxide (N2O) in order to determine how the presence/absence of shrubs and compost in urban afforestation site preparation affects the emission of this potent greenhouse gas. To complement the measurement of N2O flux, microbial biomass carbon (C) and nitrogen (N), potential net N mineralization and nitrification, microbial respiration, and soil inorganic N were measured in experimentally afforested plots in New York City, USA. Results suggest that afforestation with shrubs and trees stimulates smaller fluxes of N2O from soils than afforestation without shrubs and trees. The range of N2O flux observed from recently afforested plots was −0.031–0.641 ng N cm−2 h−1. There were no significant differences in N2O fluxes and microbial biomass C between sites with shrubs and/or one–time application of compost. The results suggest that afforestation efforts to create natural vegetation structure (i.e. canopy trees with understory plants) and foster a functional microbial community through additions of organic matter may not increase emissions of N2O to the atmosphere. Rather, this method of afforestation site preparation may tighten C and N cycles and leave N2O emissions in these urban ecosystems unchanged.
Journal: Urban Forestry & Urban Greening - Volume 15, 2016, Pages 149–154