Potential nitrogen mineralization responses of urban and rural forest soils to elevated temperature in Louisville, KY
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- 作者：T. L. E. Trammell ; C. E. Tripler ; S. C. Carper ; M. M. Carreiro
- 关键词：Urban ; rural gradients ; Forests ; Urban heat island ; Temperature ; Nitrogen cycling ; Potential N mineralization
- 刊名：Urban Ecosystems
- 出版年：2017
- 出版时间：February 2017
- 年：2017
- 卷：20
- 期：1
- 页码：77-86
- 全文大小：
- 刊物类别：Biomedical and Life Sciences
- 刊物主题：Urban Ecology; Environmental Management; Ecology; Nature Conservation;
- 出版者：Springer US
- ISSN：1573-1642
- 卷排序：20
文摘
Soil nitrogen (N) mineralization is an important process determining terrestrial N availability, and evidence suggests elevated temperatures will enhance N mineralization rates. Along a 40 km urban-rural gradient of chestnut oak forest stands in Louisville, KY, we expected N mineralization rates would be higher in urban than in rural forests in part due to increased temperatures caused by the urban heat island. However, a 12-month field study along this Louisville gradient showed that annual N mineralization rates were lower in urban than in rural stands. Since variation in precipitation inputs and other factors across this land-use gradient may be influencing soil N mineralization rates, we conducted a three-month soil incubation experiment in the lab to determine the extent to which a + 2 °C temperature difference could affect soil N mineralization in urban and rural soils. Across the range of temperatures tested, rural soils mineralized N at twice the rate of urban soils under base (7.86 vs. 3.65 mg N kg−1 AFDW soil d−1) and elevated (9.08 vs. 4.76 mg N kg−1 AFDW soil d−1) temperatures (p < 0.01). A 2 °C temperature difference, did not significantly alter total inorganic N production in urban (p = 0.272) or rural soils (p = 0.293). The proportion of nitrate produced was lower in the urban (15.1 %) than in the rural soils (72.3 %; p < 0.01). These results suggest that differences in soil organic matter quality and potentially decomposer community composition are the primary explanatory factors for forests along this Louisville gradient.