The complexity of the opaque soil matrix is a major obstacle to studying the organisms that inhabit it. Fast technological progress now offers new possibilities for the monitoring of soil biodiversity and root growth, such as in situ soil imaging. This study presents the potential of soil imaging devices to investigate the temporal dynamics and spatial distribution of soil biological activity and their interactions. The soil imaging devices were buried in a truffle field located in the south of France and set up to capture images automatically every 6 h at 1200 dpi. For the first time, root growth, mycorrhizal colonization and invertebrate occurrences – for 16 taxa – were studied simultaneously on the images captured over 3 months (between May and July 2019). The peak in root growth occurred at the end of May and beginning of June, followed by a peak in ectomycorrhizal colonization in mid-June. For invertebrates, specific dynamics of activity were observed for each taxon, reflecting contrasting phenologies. The constructed network of co-occurrences between invertebrates shows a change in its structure over the period, with a reduction of connectance. At a fine scale, oak fine roots revealed temporally variable growth rates with higher values at night. This window on the opaque soil matrix addresses many methodological challenges by allowing the monitoring of soil biological activity in an integrative, dynamic and non-destructive way. This innovative in situ imaging tool opens new questions and new ways of answering long-standing questions in soil ecology.

不透明土壤基质的复杂性是研究居住在其中的生物的主要障碍。现在，快速的技术进步为监测土壤生物多样性和根系生长提供了新的可能性，例如原位土壤成像。这项研究展示了土壤成像设备研究土壤生物活动的时间动态和空间分布及其相互作用的潜力。土壤成像设备埋在法国南部的一块松露田里，每 6 小时自动捕捉一次 1200 dpi 的图像。首次利用 3 个月（2019 年 5 月至 7 月）拍摄的图像同时研究 16 个分类单元的根生长、菌根定植和无脊椎动物的出现。 5月底和6月初是根系生长高峰，6月中旬是外生菌根定植高峰。对于无脊椎动物，观察到每个分类单元的特定活动动态，反映了对比的物候。无脊椎动物之间共现的构建网络显示出其结构在一段时间内的变化，连接性减少。在精细尺度上，橡树细根显示出随时间变化的生长速率，夜间值更高。这个不透明土壤基质的窗口通过允许以综合、动态和非破坏性的方式监测土壤生物活动，解决了许多方法学挑战。这种创新的原位成像工具提出了新的问题和回答土壤生态学中长期存在的问题的新方法。