Cover crop use is a well-established soil conservation technique and has been proven effective for erosion control and soil remediation in many arable systems. Whereas the obvious protection mechanism of cover crops occurs through the canopy, plant roots perform multiple functions. It is important to consider the soil functions delivered by different root systems in order to increase the uptake of cover crops for sustainable soil and water management. A classification of cover crop root systems up to 0.6 m deep based on functional traits will allow us to better study their potential role in soil bio-engineering, soil structural improvements for hydrological services and soil resource protection. This was a glasshouse experiment, using large 1-m³ containers filled with loam soil, loose topsoil and compacted subsoil, in which seven cover crop species (oat, rye, buckwheat, vetch, radish, mustard, phacelia) were grown for 90 days. Root cores were taken at the end of the experiment, washed and imaged to determine root traits (total root length density, average root diameter, root specific length and root surface area) for both the topsoil and subsoil layers. Root identity was determined from a distinctive combination of single root traits and related to three soil functional variables, representing soil structural improvement, runoff mitigation and erosion control. The results showed that total root length and root surface area correlate well with aggregate stability and soil macroporosity. Buckwheat, mustard and rye had significantly greater aggregate stability, as well as 10, 8 and 7% greater microporosity, respectively, at the interface with the compacted layer when compared to the control bare soil. Furthermore, average root diameter negatively correlated with soil macroporosity, indicating that cover crops with a fine root system are more beneficial for creating pore-space than those with thicker taproots. Selecting cover crop species with the right root traits is therefore crucial to improve soil health.

中文翻译：

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基于功能根性状的覆盖作物分类以改善土壤物理性质

覆盖作物的使用是一种成熟的土壤保持技术，已被证明在许多耕地系统中对侵蚀控制和土壤修复有效。覆盖作物的明显保护机制是通过冠层实现的，而植物根部则具有多种功能。重要的是要考虑不同根系提供的土壤功能，以增加覆盖作物的吸收以实现可持续的土壤和水管理。根据功能特征对深达 0.6 m 的覆盖作物根系进行分类，将使我们能够更好地研究它们在土壤生物工程、水文服务的土壤结构改进和土壤资源保护中的潜在作用。这是一个温室实验，使用大的 1-m ³装满壤土、松散的表土和压实的底土的容器，在其中种植了 7 种覆盖作物（燕麦、黑麦、荞麦、紫云英、萝卜、芥菜、phacelia）90 天。在实验结束时采集根芯，清洗和成像以确定表土层和底土层的根特性（总根长密度、平均根直径、根比长度和根表面积）。根系特征由单一根系特征的独特组合确定，并与三个土壤功能变量相关，代表土壤结构改善、径流缓解和侵蚀控制。结果表明，总根长和根表面积与团聚体稳定性和土壤大孔隙度密切相关。荞麦、芥末和黑麦具有显着更高的聚合稳定性，以及 10, 与对照裸土相比，压实层界面处的微孔率分别增加了 8% 和 7%。此外，平均根直径与土壤大孔隙度呈负相关，表明具有细根系的覆盖作物比具有较厚主根的覆盖作物更有利于创造孔隙空间。因此，选择具有正确根系特性的覆盖作物物种对于改善土壤健康至关重要。