title: Critical carbon input to maintain current soil organic carbon stocks in global wheat systems.
abstract: Soil organic carbon (SOC) dynamics in croplands is a crucial component of global carbon (C) cycle. Depending on local environmental conditions and management practices, typical C input is generally required to reduce or reverse C loss in agricultural soils. No studies have quantified the critical C input for maintaining SOC at global scale with high resolution. Such information will provide a baseline map for assessing soil C dynamics under potential changes in management practices and climate, and thus enable development of management strategies to reduce C footprint from farm to regional scales. We used the soil C model RothC to simulate the critical C input rates needed to maintain existing soil C level at 0.1° × 0.1° resolution in global wheat systems. On average, the critical C input was estimated to be 2.0 Mg C ha(-1) yr(-1), with large spatial variability depending on local soil and climatic conditions. Higher C inputs are required in wheat system of central United States and western Europe, mainly due to the higher current soil C stocks present in these regions. The critical C input could be effectively estimated using a summary model driven by current SOC level, mean annual temperature, precipitation, and soil clay content.
authors.affiliation: LAPC, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
authors.forename: Guocheng
authors.initials: G
authors.lastname: Wang
authors.affiliation: CSIRO Agriculture, GPO Box 1666, Canberra, ACT 2601, Australia.
authors.forename: Zhongkui
authors.initials: Z
authors.lastname: Luo
authors.affiliation: LAPC, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Han
authors.affiliation: LAPC, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
authors.forename: Huansheng
authors.initials: H
authors.lastname: Chen
authors.affiliation: LAPC, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Xu