Details

Autor(en) / Beteiligte

• Leavitt, S W
• Pendall, E
• Paul, E A
• Brooks, T
• Kimball, BA
• Pinter, PJ Jr
• Johnson, B
• Matthias, A
• Wall, G W
• LaMorte, R L

Titel

Stable-carbon isotopes and soil organic carbon in wheat under CO sub(2) enrichment

Ist Teil von

• The New phytologist, 2001-05, Vol.150 (2), p.305-314

Erscheinungsjahr

2001

Quelle

Wiley Online Library

Beschreibungen/Notizen

• Stable-carbon isotopic tracers were enlisted in 1996 and 1997 wheat (Triticum aestivum) free-air CO sub(2) enrichment (FACE) experiments to detect entry of new C into soil organic carbon (SOC) pools. Any enhanced soil inputs might mitigate rising atmospheric CO sub(2). The CO sub(2) used to enrich FACE plots (to ambient +190 mu mol mol super(-1)) resulted in super(13)C-depleted wheat relative to ambient plants and the native SOC. To trace new C in control plots C sub(4)-plant-derived exotic soils were placed into subplots in high-N FACE and control treatments, and a super(13)CO sub(2) gas tracer was pulsed to subplots in high-N control replicates. Under high-N, isotopic mass balance showed 6% (P = 0.003) and 5% (P = 0.04) new C in 0-15-cm and 15-30-cm FACE SOC, respectively, after 2 yr. Results from the C sub(4)-soil subplots were ambiguous, but the super(13)CO sub(2) tracer induced a SOC delta super(13)C increase (P = 0.08) at 15-30 cm in control-high N consistent with 6% new C. We infer c. 3% year super(-1) (30-40 g C m super(-2) yr super(-1)) SOC turnover in surface soils at high-N under both ambient and elevated CO sub(2). The super(13)CO sub(2)-tracer result, however, is less reliable because of lower significance, fewer replicates and heterogeneous isotopic distribution within plants.