Temperature response of soil respiration decreases with latitude and elevation in abandoned croplands

Abstract

Soil respiration (Rs), a critical component of the global carbon cycle, is highly sensitive to warming. Agricultural soils, including abandoned croplands, are large sources of carbon dioxide to the atmosphere. However, the responses of Rs and its components to warming from abandoned croplands with no further management activities remain elusive at the national scale. Here, we report the warming responses of Rs, heterotrophic respiration (Rh), and autotrophic respiration (Ra) from China’s abandoned croplands spanning a large range in latitude (22.33–46.58°N) and elevation (2–3734 m) from three-year in situ warming experiments. We found that warming treatment (+1.6 °C) significantly stimulated Rs, Rh, and Ra by 30.4%, 37.2%, and 37.3%, respectively. The response of Rs to warming was higher in abandoned croplands (19.1% °C−1) than in other terrestrial ecosystems (5.4%–9.2% °C−1), attributing to greater increases in plant biomass and soil organic carbon induced by warming. Rs was more responsive to warming in low latitude or elevation regions with high plant biomass. Under the warming conditions, the apparent temperature sensitivity (Q10) of Rs increased in low latitude and elevation regions due to a decrease in soil carbon availability but decreased in high latitude and elevation regions due to an increase in carbon availability induced by warming. Despite the positive warming response of Rs, the net ecosystem productivity in abandoned croplands slightly increased by 18.7% attributing to increased plant productivity under warming. These findings demonstrate that Rs in abandoned croplands was more sensitive to warming in warmer regions than in colder regions, underscoring the importance of latitude- or elevation-induced variations in soil carbon availability in determining the response of Rs to warming and projecting cropland carbon-climate feedback.