Embracing the dynamic nature of soil structure: A paradigm illuminating the role of life in critical zones of the Anthropocene
Embracing the dynamic nature of soil structure: A paradigm illuminating the role of life in critical zones of the Anthropocene
复制标题
DOI：
10.1016/j.earscirev.2021.103873
复制
发表时间：
2021-11
影响因子：
12.1
通讯作者：
P. Sullivan;S. Billings;D. Hirmas;L. Li;X. Zhang;S. Ziegler;K. Murenbeeld;H. Ajami;A. Guthrie-A.-G
中科院分区：
文献类型：
--
作者：
P. Sullivan;S. Billings;D. Hirmas;L. Li;X. Zhang;S. Ziegler;K. Murenbeeld;H. Ajami;A. Guthrie-A.-G
土壤形成地球表面的皮肤，调节水和地球化学循环，并在世界各地生产食品，木材和纺织品。土壤的变化及其执行一系列过程的能力对地球系统的功能有重要影响，特别是在关键区（CZ）-从树冠顶部延伸到地下水底部的区域，并容纳了地球生物圈的大部分。土壤功能的一个关键方面来自其结构，定义为土壤颗粒和孔隙的大小，形状和排列。孔隙网络为地球至少四分之一的生物多样性提供了储存空间，而孔隙空间的丰度、大小和连通性调节着定义物理和化学环境的热量、水、营养物质和气体的通量。在这里，我们回顾了土壤结构的性质，重点是它的共同进化与植物和微生物生活在土壤中，以及这些过程已被纳入流动和运输模型的程度。虽然众所周知，土壤结构可以改变与湿润和干燥的事件，经常振荡的季节性，土壤结构的动态性质，我们讨论的是一个系统的转变，导致其水文生物地球化学功能的变化，在几十年到几个世纪的时间尺度上，在人类世的碳和养分循环的重大变化已被观察到。我们认为，土壤结构的可变性，其动态，需要更好地理解和捕获的土地表面和生态系统模型，目前描述土壤结构为静态的。我们进一步认为，建模者和数学家都准备量化，并将这些动态纳入他们的研究。从这些努力中，出现了四个基本问题：1）土壤团聚体的形成和崩溃的速度，以及它们的整体安排，如何在人类世相互作用，以调节从土壤颗粒到大陆尺度的CZ功能？2)在人类世的根深分布的变化如何影响孔隙结构，以控制水文分区，地球化学转化和通量，能量和碳与大气和气候的交换，regolithweathering，从而调节CZ功能？3)在一个高CO2、气候变暖、降水模式变化的世界中，微生物功能的变化如何影响石油有机碳动态和孔隙-聚集体剖面动态？4)人类世中人类的影响传播到地下有多深，这个深度与剖面结构有何关系，以及这如何改变CZ发展的速度？联合国最近认识到，地球上33%的土壤已经退化，到2050年，90%以上的土壤可能会退化。这种认识突出了解决这些问题的重要性，这将促进对土壤结构的预测性理解。
Soils form the skin of the Earth’s surface, regulating water and biogeochemical cycles and generating production of food, timber, and textiles around the world. Changes in soil and its ability to perform a range of processes have important implications for Earth system function, especially in the critical zone (CZ)—the area that extends from the top of the canopy to the bottom of groundwater and that harbors most of Earth’s biosphere. A key aspect of the way soil functions results from its structure, defined as the size, shape, and arrangement of soil particles and pores. The network of pores provides storage space for at least a quarter of Earth’s biodiversity, while the abundance, size and connectivity of the pore space regulates fluxes of heat, water, nutrients and gases that define the physical and chemical environment. Here we review the nature of soil structure, focusing on its co-evolution with the plants and microbes that live within the soil, and the degree to which these processes have been incorporated into flow and transport models. Though it is well known that soil structure can change with wetting and drying events, often oscillating seasonally, the dynamic nature of soil structure that we discuss is a systematic shift that results in changes in its hydro-bio-geochemical function over decades to centuries, timescales over which major changes in carbon and nutrient cycles have been observed in the Anthropocene. We argue that the variable nature of soil structure, and its dynamics, need to be better understood and captured by land surface and ecosystem models, which currently describe soil structure as static. We further argue that modelers and empiricists both are well-poised to quantify and incorporate these dynamics into their studies. From these efforts, four fundamental questions emerge:1) How do rates of soil aggregate formation and collapse, and their overall arrangements, interact in the Anthropocene to regulate CZ functioning from soil particle to continental scales? 2) How do alterations in rooting-depth distributions in the Anthropocene influence pore structure to control hydrological partitioning, biogeochemical transformations and fluxes, exchanges of energy and carbon with the atmosphere and climate,regolithweathering, and thus regulation of CZ functioning? 3) How does changing microbial functioning in a high CO2, warmer world with shifting precipitation patterns influencesoil organic carbon dynamicsand void-aggregate profile dynamics? 4) How deeply does human influence in the Anthropocene propagate into the subsurface, how does this depth relate to profile structure, and how does this alter the rate at which the CZ develops?The United Nations has recently recognized that 33% of the Earth's soils are already degraded and over 90% could become degraded by 2050. This recognition highlights the importance of addressing these proposed questions, which will promote a predictive understanding of soil structure.