No-till agriculture may not bring hoped-for boost in global crop yields, study finds

No-till agriculture may not bring hoped-for boost in global crop yields, study finds
No-till farming, such as used in this Illinois soybean field, shows promise in dry regions but causes lower yields in cold, moist areas like Northern Europe, a new study finds. (Paige Buck/USDA NRCS Illinois photo)

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 , 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 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.

New findings about yield

"This review was a tremendous undertaking and is probably the largest meta-analysis done in agriculture," said co-author Bruce Linquist, a Cooperative Extension specialist at UC Davis.

After assessing more than 5,000 side-by-side observations, the researchers concluded that on average no-till negatively impacts yields at the global scale, yet several opportunities exist for more closely matching or even exceeding conventional tillage yields.

For example, yield reductions were minimized when the principles of crop rotation and residue retention were also practiced, highlighting the importance of implementing all three conservation agriculture principles as part of an integrated management system rather than no-till alone.

Moreover, when adopted in dry climates in combination with the other two principles of conservation agriculture, no-till farming performed significantly better than conventional tillage, likely due to the higher retention of soil moisture.

Dryland ecosystems are home to 38 percent of the world's population, and millions of acres of land in arid regions of sub-Saharan Africa and South Asia have been identified as suitable for sustainable intensification. Yet, the authors also caution that practicing no-till in dryland areas without the implementation of the other two principles of conservation agriculture decreases yields.

In regions with moist climates and sufficient precipitation, no-till farming actually resulted in yields that were on average 6 to 9 percent lower than with conventional tillage methods.

"No one has ever stated that there would be a significant decline like this," said Chris van Kessel, a professor of plant sciences at UC Davis and co-author of the study. "Our findings suggest that broad implementation of conservation agriculture may not be warranted in all areas, particularly where residue retention and crop rotation practices are hard to implement."


Explore further

Crops from no-till fields may need spring nitrogen boost

More information: "Productivity limits and potentials of the principles of conservation agriculture." Nature (2014) DOI: 10.1038/nature13809
Journal information: Nature

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Citation: No-till agriculture may not bring hoped-for boost in global crop yields, study finds (2014, October 23) retrieved 20 September 2019 from https://phys.org/news/2014-10-no-till-agriculture-hoped-for-boost-global.html
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Oct 23, 2014
In regions with moist climates and sufficient precipitation, no-till farming actually resulted in yields that were on average 6 to 9 percent lower than with conventional tillage methods.


I live in Louisiana, and my elders were all full-time farmers at some point in their lives, and then part-time farmers later. I actually don't know a "Lot" about it compared to them, but if you were to do no-till here your soil is going to lose nutrients over the long term.

What they tend to do is till the dead plant matter back into the ground, and aerate it at the same time. Now your dense nutrients that didn't go into the produce are returned below the surface of the soil. If you didn't till, and you get a 3 inch rain, those nutrients are on the surface of the soil and are washed away.

Also, decay processes are different in moist environments to begin with. Different chemistry,different microbes, different insects, and so forth.

Oct 23, 2014
THe article does not adequately address the key issues. The issues for maximizing production that should be addressed in the consideration of agriculture techniques are: 1) Plants need the optimal moisture level. If dry, you need to retain moisture; if wet, you may need to reduce retained moisture, depending upon the crops grown. 2) Plants need nutirants. Nutriants must be added to the soil in the appropriate quantity and type either through the addition of natural organic material or other methods. Loss of nutiants through leaching should also be considered. 3) Plant root growth should not be inhibited. Depending upon the type of soil and the type of crop tilling may or may not be necessary. The bottom line is that the potential of conservation techniques depend upon location.

Oct 23, 2014
This seems a little sketchy to me. It's well known that tillage leads to the oxidation of organic matter leading to mineralization of nutrients in the immobilized organic soil fraction. This is why there are higher yields with conventional tillage. It's just simply not sustainable year to year. No-till combined with occasional conservation tillage and crop rotation is the best practice.

The indirect cost savings of minimizing soil erosion by using no-till far outweigh average 6-9% yield increase. Probably by orders of magnitude.

I've been a student of agriculture my entire life. I've lived this shit. We really need to get beyond what brings the biggest yields. It's about using sustainable practices so that future generations can use the land we're using now.


cjn
Oct 23, 2014
The indirect cost savings of minimizing soil erosion by using no-till far outweigh average 6-9% yield increase. Probably by orders of magnitude.


I agree with you that conservative practices should be used as they can to minimize loss through erosion and subsequent waterway pollution, but from a "population perspective," the value of the yield increase is predicated on the need for achieving a specific yield per acre/hectare. If US/CAN/RUS agriculture were used solely to feed domestic markets, then you can afford to have reduced yields -as there is currently ample enough arable land. In regions where arable land is less available, yield today supersedes future costs... at least to the people that would otherwise starve. I think this is a field of study that is ripe for innovative solutions, like vertical ag or algal supplements, etc..

Oct 23, 2014
Joynerbrew is exactly correct.

Oct 23, 2014
Joynerbrew's position is certainly a position that should be considered, as a part of the sustainment of nutients strategy. However the desire/need for profit cannot be ignored. Yild remains one of the primary drivers of profit.

Oct 23, 2014
We do not need profit. We lived for a few million years without an economy, but cannot live without food which is provided by a sustainable environment.

cjn
Oct 23, 2014
We do not need profit. We lived for a few million years without an economy, but cannot live without food which is provided by a sustainable environment.


What? I'm not sure if your point is that we don't "need" profit, as we cannot consume profit for sustenance, but a farm does "need" the financial ability to sustain itself, or it does not continue to produce food.

The modern human species (homo sapiens sapiens) is ~200,000 years old, so "we" cannot have survived without anything for a greater duration than that. Further, our success as a species is, in large part, due to the formation economies -which place a value on a service or product which can be exchanged for another product or service and enable specialization.

Lastly, modern ag is not environmentally-sustainable alone, but is with the support of an economy which provides fertilizers, equipment, and power to produce food. Its not at all the best way, but disprove your argument.

cjn
Oct 23, 2014
^I will caveat my comment with: Outside of the timeline (or unless you are not human), your comments may be correct in the abstract, but not in anything approaching reality. Reality, however, is the realm in-which we must improve ourselves, and thus we must work within the boundaries we have to create the changes we desire. Ignoring reality only leads to impotent frustration and denial.

Oct 23, 2014
You misunderstand my point: Try eating your money.

Oct 23, 2014
We need to get away from using farm products to produce alcohol or diesel fuel to power motor vehicles.

Oct 24, 2014
I think there was a lot wisdom in the first curse placed on man, to paraphrase, "From now on you are going to have to till the ground with hard work and sweat."

As long as we're talking apocryphal stuff, Cthulhu begs to differ. He got first dibs in on cursing humanity.

Oct 24, 2014
a lot wisdom in the first curse placed on man, to paraphrase, "From now on you are going to have to till the ground with hard work and sweat."
Hmmm... so how come Adams kids were farmers and herders? Who taught them those skills? God? And what about all those ready-made barnyard animals and domesticated crops? Who made them? God?

We know that humans were hunter/gatherers for a several 100,000 years before agriculture was invented because that's what the evidence tells us. We also know how long it takes to change the characteristics of plants and animals via breeding and cultivation.

Unless of course you assume a god who can snap his fingers and twitch his nose and make it all come to pass in a day or 2.

But if your god could do absolutely anything at all, why did he choose to write a book that fails so magnificently to describe the world he made??? Who was he trying to kid??? People who don't know how to think for themselves??? Why did he create such people???

Oct 26, 2014
No-till agriculture has more in common with chemical warfare than farming. It was the farm program, at the behest of the poison, chemical fertilizer and manufactured food industries, that mandated spray-farming. The "big operators" adopted chem-farming so they could cover more acres and put even more of their neighbors out of business.

Go stand in a field that has been sprayed dead, there are no birds, no bugs, no cover or food for wildlife, and it is very hot. Chem-farming is the irresponsible agriculture of greed. For the first time in human history, a generation of farmers will hand the future an agriculture they cannot afford.

Under the guise of soil conservation, poison-farming has been promoted, praised and demanded by the very people who make the poison. This will be the shortest so-called green revolution yet.

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