It is difficult to have a conversation with plant pathologist and soil fertility specialist Dr. Iuean Evans without hearing the word “copper” and the important role it can play in development of a healthy, high yielding crop. But he also has recently noted that early-bird agronomic practices are important for optimizing soil available nutrients and moisture.
An Edmonton, Alberta-based researcher, Evans, who has earned the nickname in some circles as “Dr. Copper” has for years emphasized the importance of the often- overlooked micronutrient. Copper is an important nutrient to all crops, but in cereals, particularly wheat, a copper deficiency can be traced back to poor crop performance including severe lodging, low yields, low quality, delayed maturity and ergot infestation.
In a recent presentation, Evans says while the wide range of macro and micro nutrients need to be available to crops, early seeding can also help crops withstand stresses and make better use of moisture and fertility. He pointed to experiences not only with trials in his own back yard, but with farmers in Parkland County, just west of Edmonton during the 2016 growing season.
The home experience
Early-seeding a wide range of crops, just in three-inch plant pots in his own backyard improved plant hardiness, says Evans.
“March 28 I seeded barley, oats, wheat, canola, flax, peas, lentils, faba beans and soybeans at around 10 to 20 seeds per pot, one centimetre deep and placed them outdoors,” says Evans.
After a mid May frost “the only field crop that got killed off in my replicated crop trials were the soybeans,” he says. “All other crops afore mentioned showed no injury, they were ‘hardened off.’ Canola seeded in late March directly into garden soil also showed no injury. Even over wintered canola in full bloom in my yard and three feet tall showed very little cold injury.”
Seeding by conditions versus calendar
So hardening off was one benefit of early seeding, but how else did it benefit farmers in real field conditions? In Parkland County, Evans observed a mix of early- and late-seeded crops in 2016. The early-seeded crops got off to a good start with even germination and good root development, and went on to mature evenly with good yields. Many of the later-seeded crops had poorer germination, shallow root development, a considerable amount of lodging, more ergot and lower yields.
His main message: seed according to conditions and not by calendar date. “Parkland County is an area where better producers expect 60 bushels of canola and peas and 70 to 100 bushels of wheat on fertile sandy loam,” says Evans. “So what happens with the early seeders versus those who follow the calendar?”
By early April 2016 soil temperatures had reached 4 C to 5 C and there was moisture in the top inch of soil.
“Many area farmers were busy seeding wheat, barley, peas, faba beans and oats by mid-April, by late April canola was being sown,” says Evans. “About a third of the Parkland farmers held back expecting to seed at the usual time of early to mid-May.”
Unfortunately by mid-May the sandy loam cropland in this area had dried out and by late May when lots of cereal seed was being planted most fields in the eastern part of Parkland County had become bone dry in the top two to three inches.
By late May there had been no rain or moisture since the winter months. The early-sown cereal crops were six inches to a foot tall and early seeded peas where showing moisture stress. Winter wheat had headed out by early June.
The May-seeded crops — wheat, barley, oats and canola — showed sporadic or no germination by late May. In late May the rains started and several heavy showers a couple of inches or more came by week after week. The late seeded crops were emerging the last week of May and early June, whereas the early seeded crops had, due to available moisture, germinated and were a full month earlier and six inches to a foot tall.
Credit early root development
“The early-seeded cereals (mid April) grew during a period of little or no rain and as the soil dried out, likely put roots deep into the subsoil in search of moisture,” says Evans. “Late-seeded crops from late May onwards had abundant rain resulting in shallow rooting in the top six inches or so of soil.
“These soils in east Parkland County are known to be copper deficient. The early-seeded crops, due to deep rooting into the subsoil in search of moisture picked up all of the copper needed for normal growth.
“The late-seeded crops were shallow rooted in soil with five to seven per cent organic matter in the top six inches. The late-seeded crops had lots of moisture and nutrients but no copper available in the top six inches.”
Particularly in wheat and barley, copper provides the enzymes for stem lignification.
“The early-seeded crops stood up with virtually no lodging and matured early,” says Evans. “The late-seeded crops lodged badly and both wheat and barley were very slow to mature. Ergot was also present in the late-seeded crops. Low soil copper levels will also delay maturity in wheat and barley.”
The facts of the case
- Every 40 to 60 bushel crop of grain removes about one ounce of copper per acre. Peas, corn, canola and grazing cattle or hay also removes about an ounce annually.
- 100 to 200 years of farming will have removed perhaps 100 to 200 ounces of copper per acre, primarily from the top six inches or so of the soil profile. That’s six to 12 pounds of copper removed. Some research estimates there were only three to four pounds of copper in virgin soil.
- Copper is essential to form enzymes to produce lignin for stem strength, i.e. lignification.
- Copper deficiency causes pollen sterility leading to missing grain — reduced yield and ergot infection. Wheat and barley flowers never open unless they are pollen sterile.
- Copper is the key factor in maturity.
“In Parkland County many of us noted that cereal crops with adequate copper matured five to 15 days earlier,” says Evans. “Seed potato farmers here seeded a month early and harvested a month early. Those farmers who paid full attention to their crops’ nutrient requirements particularly copper and also seeded early, took off high quality, high yield cereal crops in mid-September. Canola seeded early had higher than expected yields, and peas were done by late August. “By contrast many late seeders had to deal with frozen crops during the 2016 harvest and some of that may not be harvested until spring,” he says.