US Study Shows No-Till Agriculture Unable To Prevent Nitrates

A new agricultural study from Indiana University-Purdue University Indianapolis shows that no-till agricultural practices alone are not sufficient to prevent water pollution from nitrates.

The study, funded by the U.S. Department of Agriculture, found that the no-till technique actually increases nitrate leaching, a common cause of water pollution.

Lixin Wang, a corresponding author of the study, is an assistant professor in the Department of Earth Sciences at IUPUI. Wang says the researchers examined thousands of scholarly articles in order to synthesize information from all previously published research on the no-till technique.

“What we found is very surprising,” Wang says. “We found that no-till is actually not as effective as what we previously thought.”

There are two pathways through which nitrate and other pollutants can contaminate water: surface runoff and leaching. The study found that there was little to no difference in the concentration of nitrates found in runoff from no-till fields compared to runoff from conventionally tilled fields.

However, no-till fields had higher levels of nitrate loss through leaching than those with tillage management. Wang says despite this drawback, employing the no-till technique is still worthwhile.

“You need more – other – management practices to be able to complement a no-till practice,” Wang says. “So, that’s our suggestion.”

The study cites cover cropping, intercropping and crop rotation as other methods to combine with no-till farming to reduce nitrate pollution. Wang says about 30 percent of fields in Indiana are no-till fields.