Features Agronomy Tillage
Soybeans: to till or not to till – revisited

There are many debates going on in agriculture and perhaps one of the less controversial but nevertheless important is whether no-till soybeans are working well in Eastern Canada. There could be as many farmers who disdain no-till as those who swear by it. 
Of course, the soil on a grower’s farm can influence that individual’s thinking about whether trying no-till has merit. But others say it is that very mindset, when growers start to use the practice with a hopeful attitude rather than educated determination, that can make success unlikely. Horst Bohner, provincial soybean specialist with the Ontario Ministry of Agriculture, Food and Rural Affairs, says no-till is working very well for many soybean growers. “This year is a perfect example,” he observes. “No-till fields yielded over 60 bushels per acre, in many cases. We conducted 10 tillage trials this year (2010) and only found a one bushel per acre advantage to spring tillage on average.”

However, Bohner and others stress that no-till has to be done right. “There are problems to be handled with no-till just like there are problems with conventional tillage,” he says. “Sometimes no-till has been oversold as ‘easy,’ and it should be made clear that a well-managed no-till system is not easy to achieve. However, it’s the most profitable way to grow soybeans for most growers.”

Dave Townsend agrees wholeheartedly. “Farmers are using no-till in soybeans for other reasons than yield, but if you’re managing the soil properly, you shouldn’t be losing much yield at all,” says Townsend, crop manager at Syngenta Seeds Canada. “And even if you’re losing a couple of bushels per acre, you still may be making money with no-till because of fuel and tillage operation savings.”

However, Dr. Bill Deen, an associate professor in the department of plant agriculture at University of Guelph, cautions that the yield lag average for no-till could be larger than this in the cooler regions of the province, especially during colder, wetter years. 

Good soil management, in turn, is dependent on what happens during the rest of the rotation, says Townsend. “If no-till is not being used for other crops, decreased soil friability or ‘tight’ soil can occur. We have seen the longer the fields are in no-till, the better the soil tilth becomes,” he notes. “The soil type, structure and poorly managed planting conditions can lead to a soil that has poor aeration. It gets too tight, and that affects the soybean roots, and stress lowers yield.”

Townsend also observes that many farmers are planting no-till soybeans earlier than they should. “That’s the biggest change I’ve noticed in the last 10 years. It used to be that people were waiting two or three days after farmers who till their soybeans had planted to plant no-till, but now they’re planting two to three days earlier.” They should wait, he stresses, for the soil to be fit. He adds, “Any problems with no-till are alleviated by some reduced tillage.”

Bohner echoes the sentiment. “The most reasonable approach to retaining the environmental and soil health benefits of no-till and gaining the yield benefits of tillage is through minimal tillage,” he asserts. “The plow is not necessary in most cases.”

Deen agrees. “If you’re concerned about yield lag, you don’t have to return to heavy tillage,” he says. “Even two passes with a light disc have shown in our studies to eliminate most
yield lag.”

According to Bohner, no-till is also thought to add organic matter to the soil while plowing will reduce it over time. 

To the question of whether slugs are more prevalent in no-till soybeans because of the presence of residue, Townsend and Bohner answer with a definitive yes. “Tillage does reduce slugs, but you don’t need the plow to reduce populations,” says Bohner. “Again, a relatively low amount of tillage can solve most problems.”

Better overall benefits in no-till than in tillage
There are uncertainties about whether nodulation, seed treatment, inoculants and the potential for fertilizing soybeans are any more necessary in a plowed field compared to a residue-covered one where no-till beans are planted. Bohner is not buying in. “There are no real problems with nodulation, fertilizer, or seed treatments with regard to a well-managed no-till field,” he says.

“That’s why we only find a two bushel per acre advantage to tillage over no-till in soybeans.”

However, because no-till can be a more stressful environment for a seedling, Bohner says sometimes seed treatments and inoculants can be even more beneficial in a no-till field. Deen agrees; “This is especially true in colder areas of the province,” he says. “No-till exacerbates the stresses of early season cold and wet, no matter how well-managed the field. Some amount of tillage helps to allow the soil to warm up.”

Eric Kaiser has grown no-till soybeans for nine years near Napanee, Ontario, and would never do anything else. With his son Max, Eric runs Kaiser Lake Farms, a layer-pullet chicken and 900-acre cash crop operation, with a market vegetable patch and pick-your-own strawberries as well. “No-till works just fine,” he says. “The best thing to do on Napanee clay is nothing. Everything we do on the fields reduces yield, so no-till is the only way to go.”

Nine years ago, the Kaisers used some no-till and found no yield differences between tilled fields and no-till fields. Eric stresses, however, that good drainage is a must, as is daily planter maintenance, to ensure correct planting depth and row spacing.

Some additional agronomic tips
The Kaisers also use a shallow till elsewhere in the rotation to incorporate liquid chicken manure as they spread it, but this is done more to keep odor levels down for the neighbours and avoid run-off than in any hope of aerating the heavy clay soil. “Nitrogen is expensive, and we’ll lose the N in the manure if we don’t incorporate a little bit,” he says.

Eric and Max also plant a multi-species cover crop (oats or barley, winter wheat, oilseed radish, sorghum-Sudan grass, field peas, buckwheat, sunflowers) in every field every three years that adds nitrogen to the soil. “Some research says that corn, soybean and wheat is not an adequate rotation, that you need more,” Kaiser notes. “We do a glyphosate burndown after the cover crop in the fall, and there’s a brown mat covering the field in winter that helps prevent erosion.”

The Kaisers plant their soybeans into corn stubble, and they have had only one year when slugs caused significant damage; they have watched for that a little more closely since then. In addition, Kaiser says that by using no-till and a row unit planter, they plant a seed count much below OMAFRA recommendations, which saves money. “I advise other farmers to keep your mind open and keep learning,” he says. “Go to meetings and conferences.”

Deen concludes that in most cases for most Ontario soils, there is only a slight disadvantage with no-till. Therefore, it is not worth “chasing the average one to two bushels per acre” with tillage. However, he highly recommends that growers do their own strip tests to check yield drag.