Weathering Intensity and Presence of Vegetation Are Key Controls on Soil Phosphorus Concentrations: Implications for Past and Future Terrestrial Ecosystems
Weathering Intensity and Presence of Vegetation Are Key Controls on Soil Phosphorus Concentrations: Implications for Past and Future Terrestrial Ecosystems
复制标题
DOI：
10.3390/soilsystems4040073
复制
发表时间：
2020-12
期刊：
影响因子：
3.5
通讯作者：
Rebecca M. Dzombak;N. Sheldon
中科院分区：
文献类型：
--
作者：
Rebecca M. Dzombak;N. Sheldon
磷(P)是海洋和陆地生态系统中一种重要的限制性营养物质。了解自然和人为因素对土壤中磷浓度的影响，对于预测土壤中磷的分布随气候变化的变化是至关重要的。虽然已知磷来自基岩风化，但风化、磷和其他土壤形成因素之间的关系尚未在大陆尺度上量化，这限制了我们预测磷浓度大范围变化的能力。此外，虽然我们知道铁氧化物伴生磷是陆地环境中重要的磷相，但土壤铁浓度和物种(如氧化物中的铁、活性铁)的范围和控制很差。在这里，我们探索了土壤磷和铁浓度、土壤秩序、气候和植被之间的关系，以及大约400种土壤中铁的形态。风化强度对土壤中P的浓度有细微的控制作用，P浓度在中等风化强度时达到峰值(化学蚀变指数，CIA~60)。植被(但不是植物功能类型)的存在影响了土壤对磷的积累能力。与预期相反，磷与氧化物中的铁的相关性并不比其他铁相更强。这些结果对于预测气候变化下从土壤到河流的潜在磷通量的变化和重建地球过去陆地营养限制的变化都是有用的。特别是，随着植被的存在，土壤有积累更多磷的趋势，这表明可能需要重新审视生物地球化学模型，该模型援引陆地植物的进化和传播作为地质记录中增加磷通量的驱动因素。
Phosphorus (P) is an essential limiting nutrient in marine and terrestrial ecosystems. Understanding the natural and anthropogenic influence on P concentration in soils is critical for predicting how its distribution in soils may shift as climate changes. While it is known that P is sourced from bedrock weathering, relationships between weathering, P, and other soil-forming factors have not been quantified at continental scales, limiting our ability to predict large-scale changes in P concentrations. Additionally, while we know that Fe oxide-associated P is an important P phase in terrestrial environments, the range in and controls on soil Fe concentrations and species (e.g., Fe in oxides, labile Fe) are poorly constrained. Here, we explore the relationships between soil P and Fe concentrations, soil order, climate, and vegetation in over 5000 soils, and Fe speciation in ca. 400 soils. Weathering intensity has a nuanced control on P concentrations in soils, with P concentrations peaking at intermediate weathering intensities (Chemical Index of Alteration, CIA~60). The presence of vegetation (but not plant functional types) affected soils’ ability to accumulate P. Contrary to expectations, P was not more strongly associated with Fe in oxides than other Fe phases. These results are useful both for predicting changes in potential P fluxes from soils to rivers under climate change and for reconstructing changes in terrestrial nutrient limitations in Earth’s past. In particular, soils’ tendency to accumulate more P with the presence of vegetation suggests that biogeochemical models invoking the evolution and spread of land plants as a driver for increased P fluxes in the geological record may need to be revisited.