study shows no-till alone can reduce crop 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.

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.


Staff Writers
Davis CA (SPX) Oct 27, 2014
http://www.seeddaily.com/reports/No_till_agriculture_may_not_bring_hoped_for_boost_in_global_crop_yields_999.html

I am not the biggest fan of no til but give me a giant break.

Compared to WHAT? Few people till the soil and add nothing. I just might have to find a copy of the article in Nature but this comes out of the UC Davis ag dept so I am skeptical even if I did attend there.

Many things done alone, will reduce yield. A number of measures in concert, generally gives the best results.

You have to remember the studies that were reviewed were mono-culture crops in industrial agriculture.
My take away was that the negatives can be reduced by applying combined practices.
Spraying with herbicides and using a seed drill to put in crops alone just does not cut it.

This is quoted from the article:
"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."

This study was of the singular component of what makes up the No-Till methodology, as all studies usually are focused on a single component of what ever they are studying, so while I would agree that just taking a piece of current "modern" farm land and stopping tillage would result in a reduced yield, it does not mean what it implies. The implication is that No-Till results in reduced yield, particularly in areas that get enough moisture through rains. It does not take into account any of the other things a farmer should do when practicing No-Till methodology.

The No-Till methodology was designed to mimic a natural state for land being farmed (permaculture is an example of this methodology, as is rejuvenation or holistic farming). Sure, if all you do to land that has been stripped of its ability to replenish its self by applications of chemical fertilizers, herbicides, and insecticides is leave it alone, it will take years and years to return to the prior to tilling, natural state. If you plant polyculture cover crops and then crimp roll or chop and drop these cover crops, the time it takes to return to the natural state is shortened by many years. The study ignores this, since it would diminish the results desired by those who paid for the study, so what you have is a tainted scientific study, designed to appease the funding groups.

If I took a 250 acre field that had its soil diminished by 50 years of "modern method farming" and did a proper holistic No-Till method of multi-crop cover cropping, rotational grazing by cattle and No-Till cash crop planting, in three years I would see less need for irrigation, higher humus content, better soil health, better crop health and finally higher yields than a plot the same size that was "modern method farmed" during that same three year period.

I have done this on seven farms whose cash crops are wheat, rice, soybean, corn rotational farmed.
The soils of these farms are "buckshot" clay and the fields we did the No-Till methodology on were 5% more productive at the end of the farmer's three year trial period.
These farms are now, 18 years later, completely No-Till managed and their yields are up 10% from when they were "modern method" farmed. It is not a matter of what one component of a methodology results in, it is a matter of what happens when all the components of a methodology are used.

Of course if I was Monsanto or the USDA (who gets part of their funding from companies like Monsanto) I would want to show that No-Till was a bunch of bunk so my profit margin would not go down.

Perhaps it's just my lack of knowledge of farming practices outside of my county, but no-till where I'm at includes by definition maximizing residue retention year over year. Usually tillage is what mixes the residue with water, oxygen, and soil microorganisms so that it breaks down before the next crop is planted. Is there a way to do no-till farming that does NOT involve residue retention. The distinction in this article seems inane to me.

hau,Izzy. No-till means you leave all the residue from the last crop, be it cash or cover, laying on the soil (the goal is to never have the land bare) then drill new seed directly into this with out pulling a disc or plow through the field prior to planting. If you disc in the residue, then you have disturbed the micro organisms in the soil and that is not the goal. It is true that when you have nearly total depletion of a field that you would need to do a heavy cover crop and disc that in before you could start the No-Till regime, but one you start the No-Till regime, you never bring a disc back to that field. This saves the fuel cost of plowing before planting, and it will end up with saving other fuel, fertilizer, insecticide, herbicide costs for the normal multi pass methods currently used by most farmers.

no till on dead farm land won't do good,
no till with good sound agriculture practices of a conventional farmer wouldn't do much better.
It don't happen in one year or even two three four depending on lots of variables environment,weather,condition of soil.
when you have destroyed the soil for years it will take awhile to fix it.and a good deal of money!

Hi Bryant,

Yes, that is my understanding of no-till as well, and the way the farmers that I work with are doing it. However, the article seems to make a distinction between no-till (which may decrease yields), and no-till plus residue retention which they say minimizes yield reductions. So what do they mean by the label "no-till" if it does not include residue retention? In other words, what would a farmer do to get rid of residue that does not include mechanical soil disturbance?

I can think of three: burning residue, grazing, and baling/removing residue. Generally, crop residues are of so low commercial value that it doesn't pay for the fuel costs of baling and removing it. So that option is out. Very few owners of large farming operations (those that most of the world assumes are the ones responsible for "feeding the world" in the future) manage both livestock and crops. So grazing is unlikely. Which leaves burning - fairly quick and cheap, but almost nobody is going to do it because of air quality regulations and the fact that it's just not necessary.

I just don't see this article as having any meaningful information for farmers. They say if you isolate out a single practice and implement it by itself, it may reduce yields in regions of abundant rainfall. But very few farmers in that setting would even consider getting rid of their residue through any means other than tillage, so they will by default adopt both practices if they are going to do either.

Izzy, yes the article seems to be heavily slanted with the apparent desired result being to convince farmers that No-Till doesn't work.

There are many ways to retain residue.
On my own farm, as an example, we had a lot of clearing of reclaimed land to do at the start. We turned a lot of this material into biochar and incorporated that into the soil, we also laid down a lot of the cut down material as mulch on top of the land treated with the biochar and planted crimson clover and native grasses as the cover crop. This year we will chop and drop before planting this years vegetable crops. The result so far is that we have increased the bio-matter by 10% in just this one year. The biochar will persist for at least 20 years and probably far longer, we introduced fungi spores at the same time. The continued cover cropping and chop and drop cycles will continue to increase our humus matter and this, along with the compost we make will allow us to make adjustments to the soil so that is becomes even better. Our soil right now is at a pH of 6.5, humus content of 15%(overall averaged), the soil on Buzzard's Roost is a rocky, sandy loam with an average depth of 2.5 feet, below that is bed rock that is sand stone. Water retention is currently high enough that we do not have to water but once a week when we are in the hottest, driest part of the year (august) the rest of the year there is enough water that we don't have to add water at all. Phosphate, phosphorus are near optimal, nitrogen is very well balanced too, as are most trace minerals. This is because the land lay fallow for seven years before we acquired it and it is mostly hardwood forest with just the current fields that had been cleared, we have no plans to do any deforestation since we are a homestead farm with no need to cash crop large quantities for markets.
We are changing one entire field into orchards, this will mean less land to cash crop but the fruit will be taking the place of what might have been grown there.
We supply a farm market with our excess products and will be adding eggs to that market's inventory. Other items can be added as our customer market makes requests.

No-Till methodology, by the very nature of location, must be custom designed for each plot of land, you can not just go in and make assumptions on what will work. You have to do the homework, once you know what is present, you can cover crop accordingly and insure success. There are farms near us that are totally different in soil makeup from us, so they have different covers to plant and different ways of implementation. The only constant at this time is the addition of biochars, made from their own materials, so the amendments have continuity with the needs of their soil.

No till may result in reduced yields, but you also have to factor in savings in energy costs from not plowing and tilling.

So many ways to do no till, did they use the broadfork in their no till system?

I am asking because I did not till the field this year, every row is mounded, I find the rows that were not protected with crop residue and were left bare most of the winter have gotten really compacted. Some rows with the crop residue were also fairly compacted. The rows with oat as cover crop were also compacted,though not as much and it wasnt seeded thick enough. It rains a lot here in the winter and I think using the broadfork before planting will be necessary for the first many years of the no till system. I can already see a difference in the growth of young plants in rows that I have used the broadfork. In the rows that I did not use the broadfork, all the plants are stunted or growing slower.

EDIT, the least compacted rows were the ones I grew carrots in.

Hi Miguel, yes the broad fork is a wonderful tool, I think everyone who gardens should own one.
Using a broad fork is part of a no till system, as is using a sub-soiler behind a tractor.
This is not tilling the soil (turning it over), lifting the soil layers so air can get in and humus can move down is, while not absolutely necessary, a great way to speed up the improvement of soils.