Wheat and cover crops may not be the most profitable of cash cows, but the indirect benefits to grain growers’ bottom lines are significant.
Keeping winter wheat in the rotation, that is, has been shown to consistently boost both corn and soybean yields in Ontario.
Those numbers go even higher when red clover is also employed, although covers alone can also work as an effective wheat substitute.
Why it matters: Cover crops and winter wheat can be a remedy to the declining soil organic matter on Ontario farmland.
Yield boosts or not, the benefits of improved soil structure should not be dismissed.
Evidence from long-term research trials looking at the interaction of tillage and crop rotation indicate winter wheat can boost corn yields between six and 17 bushels per acre, according to Dave Hooker, a London-area farmer and associate plant science professor at the University of Guelph’s Ridgetown campus.
The size of the effect depends on what tillage style is used, with conventional plow systems generally falling on the lower end. In soybeans, winter wheat alone adds an additional five bushels.
Underseeding red clover into winter wheat brings an additional 6.7-bushel bump to corn, plus a 70-pounds-per-acre nitrogen credit provided roots are given enough time to develop.
Hooker says red clover root growth doubles in October, so growers should try and leave it as long as is practical.
Given the consistency and significance of these findings, Hooker strongly encourages grain producers to give more consideration to how individual practices support the whole rotation system. In the case of wheat and red clover, the necessity of their inclusion is clear.
“The effect wheat has in the rotation is tremendous,” he says. “We think the reason why red clover adds to the following corn yield is it adds to soil structure improvement.”
Winter wheat and soil-building covers comprise a regular part of the rotation on Hooker’s own family operation. The former is the lynchpin of the entire system since it enables the greater incorporation of the latter, and supports yields in subsequent crops in the process.
“My overall goal is to intensify the wheat enterprise,” Hooker says, adding more growers will adopt the system if the wheat-cover crop combination can be made to “stand-alone” as a profitable strategy — one which requires more management than many growers currently give it.
“We need to consider wheat as a crop like corn and soybeans… we need to pay a lot more attention to wheat. It’s not just a crop in the rotation, it is a cash crop.”
Bigger bushels from covers alone
Research looking at yield benefits of cover crops alone is currently ongoing. Hooker says there is no evidence that cover crops increase corn yields, and no evidence monoculture covers are less impactful than multi-species mixes, at least, not yet.
In the meantime, the effects of well-established cover crops on soil structure, as well as nutrient levels and availability, should not be underestimated.
These benefits and others have led Rodney Rulon, a grain grower from Arcadia, Indiana, to use cover crops as an alternative to winter wheat in his corn-soybean rotation schedule for the last 19 years.
In that time, he and his family have managed to positively shift soil organic matter levels over their entire acreage. This has also driven overall yield increases, while allowing them to spend less on inputs such as nitrogen fertilizer.
Ensuring cover crops actually support profitability requires accurate record keeping. Rulon says growers should keep track of all costs, including fuel and cover crop seed, and measure them against the value of benefits incurred — fertilizer savings and yield increases being two obvious ones, though other more nebulous factors like reduced erosion and higher soil carbon content can also be considered and quantified.
“Conservation is the best economic model…. Soil health requires carbon capture,” says Rulon.
Refinement is necessary too. By experimenting with a variety of application techniques, species mixes, planting dates, and other factors, Rulon has developed approaches and types of cover crop that best suit the subsequent crop, and the production reality they find themselves in at any given time. Further considerations unique to individual fields (whether shallow drainage tiles are at risk of damage from deep rooting species, for example) are also important.
Dave Hooker and Rodney Rulon provided their perspectives in presentations delivered during the 2021 Midwest Cover Crop Council Conference, hosted by the University of Guelph.