Soil moisture influence on the interannual variation in temperature sensitivity of soil organic carbon mineralization in the Loess Plateau

[摘要] Temperature sensitivity of soil organic carbon (SOC) mineralization (i.e.,Q₁₀) determines how strong the feedback from global warming may be onthe atmospheric CO₂ concentration; thus, understanding the factorsinfluencing the interannual variation in Q₁₀ is important foraccurately estimating local soil carbon cycle. In situSOC mineralization rate wasmeasured using an automated CO₂ flux system (Li-8100) in long-termbare fallow soil in the Loess Plateau (35°12' N,107°40' E) in Changwu, Shaanxi, China from 2008 to 2013.The results showed that the annual cumulative SOC mineralization ranged from226 to 298 g C m⁻² yr⁻¹, with a mean of 253 g C m⁻² yr⁻¹and a coefficient of variation (CV) of 13%, annual Q₁₀ ranged from 1.48 to 1.94, with a meanof 1.70 and a CV of 10%, and annual soil moisture content ranged from38.6 to 50.7% soil water-filled pore space (WFPS), with a mean of43.8% WFPS and a CV of 11%, which were mainly affected by thefrequency and distribution of precipitation. Annual Q₁₀ showeda quadratic correlation with annual mean soil moisture content. Inconclusion, understanding of the relationships between interannual variationin Q₁₀, soil moisture, and precipitation are important to accuratelyestimate the local carbon cycle, especially under the changing climate.

[学科分类] 地球化学与岩石