Producers prefer easy and dry rather than wet and messy when it comes to copper micronutrient supplementation, says a soil scientist with Western Co-operative Fertilizers Ltd.
But what farmers don’t realize is that they are wasting their time and money with the seed placement option.
“It (seed placing copper micronutrients) does not provide an effective means of correcting the problem with copper,” said soil scientist Rigas Karamanos.
“It has not been successful consistently.”
Soil copper deficiency is common in many parts of Western Canada. Light and transitional soils are often low in copper, resulting in lower cereal crop yields. Some otherwise fertile fields will produce less than 10 bushels per acre because of copper deficiency.
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Karamanos said a foliar application of copper is the best way to increase productivity.
Tests show that a foliar application of 0.2 pounds per acre was “extremely effective” except in severely deficient fields. Yields using foliar applications were sometimes double the yields achieved by seed placing copper. Seed placement had virtually no effect.
The reason seed placement is so unsuccessful isn’t completely understood, Karamanos said. It may be a problem with copper placement in relation to the seed. Or it could be that phosphorus applied at the same time blocks the ability of plants to take up the copper. The micronutrients could also be creating a “hot zone” that the roots of growing plants avoid.
Regardless, as a method of supplementing copper it’s a complete washout, Karamanos said. With results like these, why would any farmer persevere in using seed placement? He suggested farmers may not know how ineffective the method is.
Copper nutrients used in seed placement applications come in easy-to-handle granules that can be applied directly during seeding. No additional field operations are required.
“It’s nice handling so you use them, but they don’t do anything,” said Karamanos.
Foliar applications, however, require the use of wet, sloppy and corrosive liquid copper that farmers often aren’t keen to deal with.
“It’s not a desirable product, but it’s the product that will give you the maximum.”
Timing is key
Farmers avoid foliar applications because they often demand a separate field operation. If foliar copper treatments are performed too early, the crop does not benefit. The application has to be made in cereals between the tilling and early budding stages. If a producer mixes his foliar copper treatment with a herbicide application, he’ll probably apply the copper based on the right time for the herbicide, not the copper, said Karamanos.
A producer looking at a separate foliar treatment faces higher costs. In addition to the cost of the copper, there are spraying costs.
There is a possibility that foliar copper could be applied in a mix with fungicides, but Karamanos said there has not been sufficient research to prove this is a good approach. Generally a foliar application will pay off if there is a problem, he said.
“If you don’t see a result, you probably didn’t have a copper problem.”
A normal foliar application of 0.2 pounds per acre won’t work when there’s a severe deficiency. It can’t make up for huge shortfalls of copper.
The most effective method of long-term copper supplementation is broadcasting and incorporating. However, Karamanos knew the crowd he was speaking to — the Saskatchewan Soil Conservation Association — has little interest in extra tillage.
He said if a no-till producer has a severe deficiency, where he’s getting less than 10 bushels per acre, he may have to turn to broadcasting and incorporating.
“Even if you’re in a direct seeding system, if you break it temporarily to put the copper, you still have 10 years (of direct seeding) to go back to,” said Karamanos.
Tests have shown a five pound per acre treatment of incorporated copper will be good for 10 years.
However, few farmers seem interested in undertaking such a significant correction to a copper problem. Karamanos said farmers are not always thinking long-term.
“Very rarely do I find a farmer who says ‘I’m going to spend $15 on copper because I care about what’s going to happen 10 years from now,'” said Karamanos.
“However, I do find they’re willing to waste $5 a year on seed placement that doesn’t work. People want to have their return in the year of application.”
That isn’t always possible, Karamanos said, unless the field is severely depleted.
He told producers any supplementation under 3.5 pounds per acre is far less cost effective. The smaller supplementation will cause some effect on the crop, but results leap as the rate increases.
“You’re going to broadcast and incorporate and put in two pounds for $10 and get back (an extra) three to four bushels,” said Karamanos.
“If you put in 31/2 pounds for $17.50 you’ll get (an increase of) 20 bushels. It’s not a proportional increase. It’s quite a dramatic increase.”
