Partitioning soil surface CO₂ efflux into autotrophic and heterotrophic components, using natural gradients in soil δ¹³C in an undisturbed savannah soil

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• 作者：Peter Millard ; Andrew J. Midwood ; John E. Hunt ; David Whitehead ; Thomas W. Boutton
• 关键词：Soil respiration ; Partitioning ; Stable isotopes ; Irrigation ; C₃ and C₄ vegetation
• 刊名：Soil Biology & Biochemistry
• 出版年：2008
• 出版时间：July 2008
• 年：2008
• 卷：40
• 期：7
• 页码：1575-1582
• 全文大小：330 K

文摘

We used natural gradients in soil and vegetation δ¹³C signatures in a savannah ecosystem in Texas to partition soil respiration into the autotrophic (Ra) and heterotrophic (Rh) components. We measured soil respiration along short transects from under clusters of C₃ trees into the C₄ dominated grassland. The site chosen for the study was experiencing a prolonged drought, so an irrigation treatment was applied at two positions of each transect. Soil surface CO₂ efflux was measured along transects and CO₂ collected for analysis of the δ¹³C signature in order to: (i) determine how soil respiration rates varied along transects and were affected by localised change in soil moisture and (ii) partition the soil surface CO₂ efflux into Ra and Rh, which required measurement of the δ¹³C signature of root- and soil-derived CO₂ for use in a mass balance model.