Compound-specific radiocarbon analysis as new tool to investigate C-dynamics in sustainable agriculture

农业集约化是人为二氧化碳的主要来源，反过来又加剧了全球变暖和气候变化。虽然许多农业实践旨在提高生产力，如犁地或使用无机肥料，但它们也破坏了天然的碳储存机制。导致矿化的有机物变成二氧化碳，然后排放到大气中。农业土壤中的碳固存是恢复土壤有机质和对抗人为二氧化碳排放的重要机会。因此，英国加入了旨在每年增加0.4%农业土壤碳储量的“千分之四”倡议。为了实现这一目标，必须对当前的碳储量进行量化，并且必须了解驱动土壤有机质储存的机制。最近，化合物由于其分子性质而具有内在顽固性的观点受到了根本性的质疑。相反，目前的研究假设生物和物理化学稳定机制是长期持续的原因。然而，这种稳定性可能因生物化学类别和位置而异。该项目将利用在Rothamstead研究所进行的长期实验，研究新鲜和存档的土壤。高度发达的分馏方法将用于分离和定量特征目标化合物。这些馏分也将使用布里斯托尔大学开创的高场核磁共振方法进行纯度检查。此外，使用布里斯托尔大学放射性碳加速器的14C测量将用于确定这些目标化合物的周转率，并阐明这些速率如何依赖于生物或物理化学保护机制与它们的内在顽固性。这些目标化合物的选择将与Rothamsted研究所合作，因为这种机制的理解将有助于RothC模型的发展，以及为旨在提高农业可持续性的农业管理决策提供信息。

Agriculture intensification is a key source of anthropogenic carbon dioxide, in turn contributing to global warming and climate change. Whilst numerous agricultural practices aim to improve productivity, such as ploughing or use of inorganic fertilizers, they also disrupt natural carbon storage mechanisms. Causing mineralisation of the organic matter to carbon dioxide, then emitted to the atmosphere. Carbon sequestration in agricultural soils represents a vital opportunity to recover soil organic matter and combat anthropogenic carbon dioxide emissions. As such the UK has joined the 4 pour mille initiative which aims to increase carbon storage in agricultural soils by 0.4% per year. To achieve this goal the current amount of carbon stored must be quantified and the mechanisms driving soil organic matter storage must be understood. Recently, the view that compounds possess an intrinsic recalcitrance, due to their molecular properties, has been fundamentally questioned. Instead current research has postulated that biological and physico-chemical stabilisation mechanisms are responsible for long term persistence. However, this stabilisation may vary between biochemical classes and locations. The project will utilise the long term experiments conducted at Rothamstead Research, studying both fresh and archived soils. Highly developed fractionation methods will be used to isolate and quantify characteristic target compounds. These fractions will also be purity checked using high field NMR approach pioneered at the University of Bristol. Additionally, 14C measurements using the University of Bristol radiocarbon accelerator will be used to determine the turnover rates of these target compounds and elucidate how these rates are dependent on the biological or physico-chemical protection mechanisms versus their intrinsic recalcitrance. Selection of these target compounds will be in collaboration with Rothamsted Research, as this mechanistic understanding will contribute to development of the RothC model, as well as informing agricultural management decisions aiming to improve agricultural sustainability.