Chinese Researchers Develop Soil “Stethoscope” for Real-Time Moisture Monitoring

Soil moisture condition is the foundation of agricultural production, determining the growth and final yield of crops. Researchers from the Institute of Geology and Geophysics, Chinese Academy of Sciences, and other institutions have developed a soil “stethoscope” using distributed optical fiber sensing technology, achieving minute-level real-time monitoring of soil moisture fluctuations in farmland for the first time and providing a new perspective for understanding the impact of different tillage methods on soil health.

The research findings were published online in the journal Science on the 20th. A long-standing challenge for agronomists has been accurately grasping the impact of tillage methods on soil structure without damaging the soil. To address this problem, the research team laid optical fibers on the surface of farmland soil, inferring the dynamics of soil particle structure by capturing changes in the propagation speed of seismic waves generated by background earth noise in the soil.

The team proposed a new “soil dynamic capillary stress” model. With the help of this model, data monitored by optical fibers can clearly restore the pore network characteristics deep in the soil like a CT scan, treating soil as a porous medium rather than a simple collection of particles, where pore structures serve as “capillaries” maintaining water circulation.

This technology can also “diagnose” the traces of soil modification by different tillage methods. Optical fiber data show that in areas with traditional frequent tillage, short-term rainfall causes water to accumulate on the shallow surface and be difficult to infiltrate, followed by rapid evaporation and loss. Meanwhile, the heavy pressure of agricultural tools accelerates the capillary water absorption of shallow soil, exacerbating water loss.

In contrast, in soil with no-tillage or less human interference, water can seep down quickly and be stored, providing stable water supply for crop roots like a sponge. This distinction highlights the technology’s ability to reveal the impact of different tillage practices on soil water retention.

The research ingeniously applies seismological observation methods to agricultural scientific research, offering a new perspective for understanding the interaction between plants and soil. Looking ahead, the combination of optical fiber sensing and artificial intelligence technology is expected to realize high-precision, real-time monitoring of soil moisture in large-scale farmland.

This technological breakthrough will provide solid data support for the development of water-saving agriculture and refined farmland management, further promoting the sustainable development of agricultural production in China.