UC Findings: No-Till vs. Conventional Tillage Practices

UC Davis. 19 November 2014.  No-till farming, a key conservation agriculture strategy that avoids conventional plowing and otherwise disturbing the soil, may not bring a hoped-for boost in crop yields in much of the world, according to an extensive new meta-analysis by an international team led by the University of California, Davis.

As the core principle of conservation agriculture, no-till has been promoted worldwide in an effort to sustainably meet global food demand. But after examining results from 610 peer-reviewed studies, the researchers found that no-till often leads to yield declines compared to conventional tillage systems. It still shows promise for yield gains in dryland areas, however.

The landmark findings from their review are published online Oct. 22 in the journal Nature.

“The big challenge for agriculture is that we need to further increase yields but greatly reduce our environmental impacts,” said Cameron Pittelkow, who co-authored the study as a postdoctoral scholar at UC Davis and is now on the faculty of the University of Illinois.  “The common assumption that no-till is going to play a large role in the sustainable intensification of agriculture doesn’t necessarily hold true, according to our research findings.”

About conservation agriculture

Conservation agriculture is currently practiced on 125 million hectares of land globally, an area nearly as big as the total U.S. cropland. Three key principles guide the concept: minimizing soil disturbance (also called no-till farming), protecting the soil with cover crops or leftover crop residue, and rotating the crops.

The goals of conservation agriculture are to improve long-term productivity, profits and food security, particularly under the threat of climate change. Because conservation agriculture avoids tillage, it is less time-consuming and can be more cost-effective than conventional farming methods.

In recent years, however, there has been some disagreement about the impact of no-till farming practices on yield.  read more