1. Root exudation is a key component of nutrient and carbon dynamics in terrestrial ecosystems. Exudation rates vary widely by plant species and environmental conditions, but our understanding of how root exudates affect soil functioning is incomplete, in part because there are few viable methods to manipulate root exudates in situ. To address this, we devised the Automated Root Exudate System (ARES), which simulates increased root exudation by applying small amounts of labile solutes at regular intervals in the field.
2. The ARES is a gravity‐fed drip irrigation system comprising a reservoir bottle connected via a timer to a micro‐hose irrigation grid covering c. 1 m²; 24 drip‐tips are inserted into the soil to 4‐cm depth to apply solutions into the rooting zone. We installed two ARES subplots within existing litter removal and control plots in a temperate deciduous woodland. We applied either an artificial root exudate solution (RE) or a procedural control solution (CP) to each subplot for 1 min day⁻¹ during two growing seasons. To investigate the influence of root exudation on soil carbon dynamics, we measured soil respiration monthly and soil microbial biomass at the end of each growing season.
3. The ARES applied the solutions at a rate of c. 2 L m⁻² week⁻¹ without significantly increasing soil water content. The application of RE solution had a clear effect on soil carbon dynamics, but the response varied by litter treatment. Across two growing seasons, soil respiration was 25% higher in RE compared to CP subplots in the litter removal treatment, but not in the control plots. By contrast, we observed a significant increase in microbial biomass carbon (33%) and nitrogen (26%) in RE subplots in the control litter treatment.
4. The ARES is an effective, low‐cost method to apply experimental solutions directly into the rooting zone in the field. The installation of the systems entails minimal disturbance to the soil and little maintenance is required. Although we used ARES to apply root exudate solution, the method can be used to apply many other treatments involving solute inputs at regular intervals in a wide range of ecosystems.

中文翻译：

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自动根分泌物系统（ARES）：一种定期向田间土壤施用溶质的方法。

1. 
   根系分泌物是陆地生态系统养分和碳动态的关键组成部分。渗出率因植物种类和环境条件而异，但我们对根系分泌物如何影响土壤功能的理解并不完整，部分原因是几乎没有可行的方法来原位操纵根系分泌物。为了解决这个问题，我们设计了自动根分泌物系统（ARES），该系统通过在现场定期施加少量不稳定溶质来模拟根分泌物的增加。
2. 
   ARES 是一种重力滴灌系统，包括一个储水瓶，通过计时器连接到覆盖c 的微型软管灌溉网格。 1米² ；将 24 个滴头插入土壤 4 厘米深，将溶液涂抹到生根区。我们在温带落叶林地现有的垃圾清除和控制地块内安装了两个 ARES 子地块。我们在两个生长季节期间将人工根分泌物溶液 (RE) 或程序控制溶液 (CP) 应用于每个子小区 1 分钟天^-1 。为了研究根系分泌物对土壤碳动态的影响，我们测量了每月的土壤呼吸和每个生长季节结束时的土壤微生物生物量。
3. 
   ARES 以c的速率应用解决方案。 2 L m ^-2周^-1不显着增加土壤含水量。稀土溶液的施用对土壤碳动态有明显的影响，但响应因凋落物处理而异。在两个生长季节中，在枯枝落叶清除处理中，RE 子区的土壤呼吸比 CP 子区高 25%，但在对照区中则不然。相比之下，我们观察到对照凋落物处理的 RE 子小区中微生物生物量碳 (33%) 和氮 (26%) 显着增加。
4. 
   ARES 是一种有效、低成本的方法，可将实验溶液直接应用于田间的生根区。系统的安装对土壤的干扰最小，并且几乎不需要维护。尽管我们使用 ARES 来应用根系分泌物溶液，但该方法还可用于在广泛的生态系统中应用涉及定期输入溶质的许多其他处理方法。