Deeply Plowing Farm Fields Can Do More Harm Than Good

By Carolyn Gramling

For thousands of years, farmers have prepared their fields for planting by overturning the soil. It helps them the manage the moisture, nutrients and flow of air underfoot. But modern farming’s deep plowing and heavy machinery often do more harm than good, researchers report.

All that soil turnover disrupts the natural paths that water takes to percolate into the root zone. And this is not a problem just for growing crops. Breaking down the network of pores that water wants to move through also makes the soil less resilient to flooding and drought. So concludes a team of scientists in the April 16 Science.

Qibin Shi is a geophysicist with the Chinese Academy of Sciences in Beijing. He was part of a team that fashioned a dense array of sensors out of fiber-optic cables. Such cables find use in more than just high-speed internet. They also can become powerful tools for seismology — and not just for earthquakes. They’re proving sensitive enough to detect even the tiny vibrations triggered as water moves through soil.

Shi’s group installed these cables along the edges of 27 plots of land at a university test farm in Newport, England. The plots were treated one of three ways. Nine went unplowed. Another nine were tilled to a depth of 10 centimeters (4 inches). The last nine were turned over to a depth of 25 centimeters (almost 10 inches). Within each group, plowing machinery of different weights were used. Why? The heavier they are, they more they can compact the soil.