Clarifying confusions over carbon conclusions: antecedent soil carbon drives gains realised following intervention

作者：Albert Muleke, Matthew Tom Harrison, Rowan Eisner, MB Yanotti, Peter de Voil, Shah Fahad, Wang Fei, Puyu Feng, Carla Ferreira, Daniel Forster, Xionghui Gao, Ke Liu, Jianguo Man, Lixiao Nie, Jiangwen Nie, Zhiming Qi, Narasinha Shurpali, Weilu Wang, Rui Yang, Xiaogang Yin, Feng Zhang, Yunbo Zhang, Jin Zhao · 发表于：Global Environmental Change Advances · 年份：2023 · DOI：10.1016/j.gecadv.2023.100001 · 被引用次数：28 · 研究领域：Soil Carbon and Nitrogen Dynamics、Climate change impacts on agriculture、Soil and Water Nutrient Dynamics

Carbon removals associated with incremental gains in soil organic carbon (SOC) at scale have enormous potential to mitigate global warming, yet confusion over contexts that elicit SOC accrual abound. Here, we examine how bespoke interventions (through irrigation, fertiliser, crop type and rotations), antecedent SOC levels and soil type impact on long-term SOC accrual and greenhouse gas (GHG) emissions. Using a whole farm systems modelling approach informed using participatory research, we discovered an inverse relationship between antecedent SOC stocks and SOC gains realised following intervention, with greater initial SOC levels resulting in lower ex poste change in SOC. We found that SOC accrual was greatest for clays and least for sands, although changes in SOC in sandy loam soils were also low. Diversified whole farm adaptations – implemented through inclusion of grain legumes within wheat/canola crop rotations – were more conducive to improvement in SOC stocks, followed by Intensified systems (implemented through greater rates of irrigation, farm areas under irrigation, nitrogen fertiliser and inclusion of rice and maize in crop rotations). Adaptations that Simplified farm systems by reducing irrigation and fertiliser use resulted in the lowest SOC accrual. In most cases, long-term SOC stocks fell when SOC at the outset was greater than 4–5%, regardless of intervention made, soil or crop type, crop rotation, production system or climate. We contend that (1) management in...