沙漠和干旱灌木丛
生态系统
矿化(土壤科学)
氮气循环
生态学
环境科学
湿地
农学
生物
土壤水分
氮气
栖息地
化学
有机化学
作者
Carlos A. Wilson,Robert J. Mitchell,Joseph J. Hendricks,Lindsay R. Boring
摘要
The productivity of many temperate forests is nitrogen limited. Controls on N availability are particularly important in fire-maintained ecosystems such as longleaf pine - wiregrass (Pinus palustris Mill. - Aristida stricta Michx.) forests of the Coastal Plain of the southeastern United States, where periodic burning can result in substantial N losses. This study quantifies variation in net N mineralization across a complex ecological gradient for longleaf pine - wiregrass forests, from dry sandhills to wet-mesic sites adjacent to wetlands, for the first year after burning. Net N mineralization was consistently higher for the xeric site and declined as soil moisture status increased. Higher N availability was primarily due to higher rates of net nitrification in these plots, suggesting possible substrate-induced influences. Temperature was positively related to net N mineralization, while percent soil moisture was inversely correlated to net N mineralization. The greater N availability on dry sites may reflect greater quality organic matter inputs resulting from a significant hardwood (Quercus laevis Walt. predominately) component, and (or) it may reflect microclimate differences (warmer soil) that accelerate decomposition of detritus in soil.
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