Show me the data to prove a product’s benefits

A progressive farmer tweeted to his followers that he had just applied humic acid with his sprayer. A link to his blog post made humic acid sound like a miracle product.

Probably quoting company literature, the producer said humic acid increases nutrient uptake, drought tolerance and seed germination.

He also wrote that humic acid increases the availability of nutrients in fertilizers and those already existing in the soil.

But wait, there’s more. It will help to aerate the soil from the inside. It will also help to lower the pH of the soil to a more neutral level and flush high levels of salts out of the root zone, all of which will help to promote better plant health and growth.

I replied with a rather insensitive tweet saying that it sounded like snake oil.

In the resulting Twitter conversation, some respondents agreed with me, but many were humic acid believers.

“Two dollars an acre on humates applied with our granular urea has given us a minimum $20 an acre return over the last five years,” claimed one post.

Another said: “We have seen good results applying 10 pounds per acre of humates in our low organic matter soils. It’s 100 percent carbon, the building block.”

Someone from the scientific community tweeted that little research has been done on humic/fulvic acid application in this region but that the University of Saskatchewan is starting to do some cursory work.

Another tweet asked me: “When was the last time you looked at the literature?”

Truthfully, I’ve always dismissed humic acid along with a sizable number of other wondrous soil amendments being marketed by various companies. My view has always been that if it made economic sense, someone would have proven it by now.

But a quick internet search yields a lot of posts about humic acid and its supposed benefits. Even though it’s produced by the degradation of organic matter, there are also people who believe in its benefits as a nutritional supplement.

Unfortunately, the composition and consistency varies greatly among the products being marketed.

I’m always wary about any product claiming a multitude of benefits at a very low application rate. As soil scientist Rigas Karamanos says: “In God we trust. Everyone else bring replicated data.”

Unfortunately, most producers trying unproven products don’t do proper trials to determine economic viability.

Typically, the product will be applied on one field and not another and then the two fields will be compared at harvest time.

Unless the yield difference is massive, this method of testing doesn’t tell you much. One field can yield better than an adjacent field for a host of reasons.

With GPS, it’s now fairly easy to use a new product on passes one, three, five and seven and then go back and fill in the other passes without using the product. Run a narrower combine header down the centre of each pass at harvest time and use a weigh wagon to get accurate yield determinations. Take steps to make the comparison as valid as possible.

If results are all over the map between the treated and untreated passes, your coefficient of variation is probably too large to come up with meaningful conclusions.

I’m a skeptic on humic acid and many of the other products that seem too good to be true, but meaningful data is difficult to dismiss.

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