Submitted by: Tracie Westington, Quinte Regional Communication Coordinator

The importance of crop rotation for soil health has been understood and utilized by farmers for centuries. In today’s global economy some crop productions are simply more beneficial to the bottom line than others. Great soil health may not be enough to pay the bills and decisions are made that will help the farmer make money.

In Southern Ontario, our typical crop rotation is soybeans, wheat and corn. In the current marketing year, all of those crops are profit-making commodities, but this is not always the case. Four or five years ago, it became evident in the Quinte region that wheat was being left out of the usual rotation. If it wasn’t financially viable, why would you grow it? Instead of wheat, some farmers would plant a cover crop after the beans came off in an effort to improve soil health, or they did a straight corn, soybean rotation.

Quinte’s Tier Two proposal was to relay-crop, using wheat and soybeans. Relay cropping refers to having two crops growing in the same field at the same time, but are at different maturity levels. This proposal would allow farmers to plant wheat into the rotation, while also maintaining financial viability. The idea came out of the US, where social media has brought it to the attention of Ontario growers. The program has just finished its third year in Ontario. Quinte SCIA, Huron SCIA and Peter Johnson, aka “Wheat Pete”, are all contributing data on their trials.

The idea was that the soil would get the benefit of wheat in crop rotation and the farmer would financially benefit from the higher valued, “extra” crop of soybeans. In areas of the US, were relay cropping is utilized, each crop produces less than it would if it were single cropped, but the two crops combined produce more overall.

Three farmers from Northumberland SCIA have done test plots over the last three years with varied results. In the included pictures, winter wheat was planted in the fall in twin rows on 30-inch centres by plugging the two middle runs in a centre seed drill. In the spring, the beans are planted into the open rows. Ideally, wheat is seeded at a population of 1.2 million seeds/acre vs the traditional 1.6-1.8 million. Soybeans are seeded at a slightly lower-than-normal population of 140,000/acre vs. 160,000.

Fungicides are applied to wheat as usual, and have no negative affect on the beans growing at their side. The wheat also acts as a weed barrier to the soybeans.

When the wheat is ready to harvest, special skid shoes mounted on the combine header gently push the beans over and out of the way. At this stage of the soybeans’ development, they quickly bounce back with little-to-no damage.

After the wheat is harvested, a pass of glyphosate is applied to the field to keep the weeds and voluntary wheat from growing and competing with the remaining beans.

At this point, with the competition from the wheat gone, timely rains and the remaining heat of the summer, the beans are expected to bush outwards and fill in. They are then harvested as usual once they have matured and dried down.

In 2018, the wheat yielded well, up to 94% vs. the check plot. Combining of the beans, however, was abandoned after only yielding 5 bu/acre vs. a 65 bu check plot.

In 2019, wet soil conditions resulted in one of the test plots not getting beans planted. The wheat yield in that test plot was almost as high as the check plot. Another plot that year yielded the best beans, 15 bu vs 42 bu in the check plot. The wheat on that test plot suffered a rare disease, as did the check plots, bringing yield down by almost 50%.

In 2020, only one test plot was planted with similar results to the 2018 test plot. The wheat yielded up to 88% of the check plot rate, but the beans were not combined as a 5 bu/acre yield was estimated.

Field visits during the growing season showed that the wheat was doing well, while the beans’ roots showed little sign of moisture. In 2019, rain came at the right time and gave beans the boost they needed after the wheat was harvested, but the yield was still relatively low. The conditions were just not there for the 2018 and 2020 crop. The beans did not seem to have enough growing season after the wheat was harvested to produce adequate pods.

As for the health of the soil, if wheat was already part of the crop rotation, there was no benefit to soil health in relay cropping. If it was not part of the rotation but added in as a relay, the soil health was improved. There is an alternate argument that cover crops in the fall are just as effective at maintaining soil health as the relay wheat.

For Quinte SCIA, the results of the Tier Two project were not as good as hoped for. Research into different growing variables could yield better results. Ground types, row orientation to the sun, and longer day bean hybrids are all factors that could be investigated to get more successful results. More time and research would be needed to find out.

The final results of the Quinte data, along with information collected by Huron SCIA, and information from Peter Johnson’s trial will be published in its entirety at a later date.