The structure of soil is critical for the ecosystem services it provides since it regulates many key soil processes, including water, air and solute movement, root growth and the activity of soil biota. Soil structure is dynamic, driven by external factors such as land management and climate and mediated by a wide range of biological agents and physical processes operating at strongly contrasting time‐scales, from seconds (e.g., tillage) to many decades (e.g., faunal activity and soil aggregation). In this respect, positive feedbacks in the soil–plant system may lead in the longer term to soil physical degradation or to the recovery of structurally poor soils. As far as we are aware, no existing soil‐crop model can account for such processes. In this paper, we describe a new soil‐crop model (USSF, Uppsala model of Soil Structure and Function) that accounts for the effects of soil structure dynamics on water and organic matter cycling at the soil profile scale. Soil structure dynamics are expressed as time‐varying physical (bulk density, porosity) and hydraulic properties (water retention, hydraulic conductivity) responding to the activity of biological agents (i.e., earthworms, plant roots) and physical processes (i.e., tillage, soil swell‐shrink) at seasonal to decadal time‐scales. In this first application of the model, we present the results of 30‐year scenario simulations that illustrate the potential role and importance of soil structure dynamics for the soil water balance, carbon storage in soil, root growth, and winter wheat yields on two soils (loam and clay) in the climate of central Sweden. A sensitivity analysis was also performed for these two scenarios using the Morris method of elementary effects, which revealed that the most sensitive parameters controlling soil structure dynamics in the USSF model are those determining aggregation induced by organic matter turnover and swell/shrink. We suggest that the USSF model is a promising new tool to investigate a wide range of processes and phenomena triggered by land use and climate change. Results from this study show that feedback in the soil‐crop system mediated by the dynamics of soil physical and hydraulic properties are potentially of central importance for long‐term predictions of soil water balance, crop production, and carbon sequestration under global change.

中文翻译：

---

土壤结构动力学、水文过程和有机质循环之间的相互作用：一种新的土壤-作物模型

土壤结构对其提供的生态系统服务至关重要，因为它调节许多关键的土壤过程，包括水、空气和溶质运动、根系生长和土壤生物群的活动。土壤结构是动态的，由土地管理和气候等外部因素驱动，并由各种生物因子和物理过程介导，这些生物因子和物理过程在强烈对比的时间尺度上运行，从几秒（例如，耕作）到几十年（例如，动物活动）和土壤聚集）。在这方面，从长远来看，土壤-植物系统的正反馈可能导致土壤物理退化或结构不良土壤的恢复。据我们所知，现有的土壤作物模型无法解释此类过程。在本文中，我们描述了一种新的土壤作物模型（USSF，土壤结构和功能的乌普萨拉模型），该模型解释了土壤剖面尺度上土壤结构动力学对水和有机质循环的影响。土壤结构动力学表示为响应生物制剂（即蚯蚓、植物根）的活动和物理过程（即耕作、土壤）的时变物理（容重、孔隙度）和水力特性（保水性、导水率）季节性到十年时间尺度上的膨胀-收缩）。在该模型的首次应用中，我们提出了 30 年情景模拟的结果，说明了土壤结构动力学对两种土壤的土壤水平衡、土壤碳储存、根系生长和冬小麦产量的潜在作用和重要性（壤土和粘土）在瑞典中部的气候中。还使用基本效应的 Morris 方法对这两种情况进行了敏感性分析，结果表明 USSF 模型中控制土壤结构动力学的最敏感参数是那些确定由有机物周转和膨胀/收缩引起的聚集的参数。我们认为 USSF 模型是一个有前途的新工具，可以研究由土地利用和气候变化引发的各种过程和现象。这项研究的结果表明，土壤物理和水力特性动态介导的土壤-作物系统反馈对于全球变化下土壤水平衡、作物生产和碳封存的长期预测具有潜在的核心重要性。