Scientists at Harper Adams University in the United Kingdom used fiber optic cables and distributed acoustic sensing to demonstrate how plowing destroys soil structures that hold water. The research, detailed in a new paper, shows tilled fields retain less moisture than undisturbed ones despite appearing looser. Findings highlight benefits of regenerative farming practices like no-till agriculture.
Researchers buried fiber optic cables across experimental fields at Harper Adams University's 20-year outdoor laboratory, where adjacent plots receive varying levels of tilling. Employing distributed acoustic sensing (DAS), they analyzed seismic waves from rain, wind, and vehicles passing nearby. These waves travel slower through wet soil than dry soil due to capillary forces that stiffen the ground, similar to how wet beach sand firms up compared to dry sand nearby, according to Marine Denolle, senior author and earth scientist at the University of Washington. The data revealed that tilling obliterates tiny channels—worm holes, root holes, and bug holes—that act as reservoirs for water, reducing infiltration even as plowed soil looks more absorbent. David Montgomery, geomorphologist at the University of Washington and coauthor, called this counterintuitive: “You’d think that breaking up the ground surface would allow more water to get down into it. But if you plow it often enough, hard enough, you kind of pulverize it.” Tilling also depletes long-term soil fertility, boosts carbon emissions, and necessitates synthetic fertilizers, which pollute waterways and contribute to warming. Montgomery advocates regenerative practices: “No-till — combined with cover crops and a diversity of crops — can basically lead to less agrochemical reliance, better soil organic matter contents, comparable yields, [and] lower diesel use.” Experts like Jonathan Ajo-Franklin of Rice University praised the innovative DAS application for monitoring soil health. As droughts worsen with climate change, such insights could guide farmers toward sustainable methods including livestock grazing, compost, and diverse crops like nitrogen-fixing legumes.