The low protection strategy of no-tillage agricultural yield is in crisis.

Compared with traditional tillage systems, no-tillage often leads to a decline in output. However, no-tillage still shows output benefits in arid areas.

No-tillage agriculture, a key strategy based on conservation agriculture, can prevent traditional tillage from damaging the soil, but may not bring hope to boost crop yields in most parts of the world. This conclusion is reached by a new large-scale meta-analysis report by the international team of the University of California, Davis.

As the core principle of conservation agriculture, no-tillage has been trying to promote the sustainable satisfaction of global food demand around the world. However, after accounting for the results of 610 peer-reviewed studies, the researchers found that no-tillage often led to a decline in output compared with traditional farming systems. However, no-tillage still shows output benefits in arid areas. The landmark study was published online in the journal Nature.

"one of the big challenges for agriculture is that we need to further increase production while greatly reducing the impact on the environment." Cameron Pittelkow said. He co-authored the study as a postdoctoral scholar at the University of California, Davis, and is now a faculty member at the University of Illinois.

"according to our findings, the common assumption that no-tillage will play a big role in sustainable and intensive agriculture is not necessarily true." He said.

Conservation agriculture is practiced on 1.25 million hectares of land around the world, which is almost as large as the total arable land in the United States. The three guiding principles of conservation agriculture are: minimizing soil disturbance (also known as no-tillage), protecting soil by covering crops or crop residues, and rotating crops.

The goal of conservation agriculture is to increase long-term productivity, increase income output and ensure food security, especially under the threat of climate change. Because conservation agriculture avoids farming, it is less time-consuming and can be more cost-effective than traditional farming methods. However, in recent years, there have been some differences on the impact of no-tillage farming methods on yield.

"this research is a daunting task, and it is very likely to be the largest meta-analysis in agriculture." Said Bruce Linquist, another co-author and co-promotion expert at the University of California, Davis.

After evaluating more than 5000 parallel observations, the researchers concluded that, on average, no-tillage agriculture had a negative impact on yields worldwide, although there were several opportunities that were very close to or even exceeded the yields of conventional tillage.

For example, when yield reduction is minimized, the principles of crop rotation and residue retention should be implemented. It is emphasized that the principle of conservation agriculture is part of three integrated management systems, rather than just no-tillage.

In addition, compared with the combination of the other two principles of conservation agriculture in dry climate, no-tillage has a better effect than traditional tillage, which may be due to the higher soil water content.

38% of the world's people live in dryland ecosystems. Millions of acres of land in arid areas of sub-Saharan Africa and Asia have been identified as suitable for intensive development. However, the researchers also warn that no-tillage can be implemented to increase yield in dryland areas, but the other two principles of conservation agriculture cannot be absent.

In areas with humid climate and abundant precipitation, the actual production of no-tillage agriculture is 6% to 9% lower than that of traditional tillage.

"No one has ever verified that there will be a significant decline similar to this." Chris van Kessel said. He is a professor of botany at the University of California, Davis and a co-author of the study. "our study found that widespread implementation of conservation agriculture may not be guaranteed in all regions, especially in areas where crop rotation and retention residues are difficult to meet."