Farming Magazine - May, 2010


Forages: Beware of Foo-Foo Dust

By Everett D. Thomas

University extension specialists call them “unconventional soil additives;” I call them foo-foo dust. They include a vast range of products advertised to increase crop yield and/or quality, not by directly supplying nutrients in the amounts crops need, but by “unlocking the hidden potential of your soils,” “enhancing the biological activity of soil bacteria” and other pie-in-the-sky claims. High fertilizer prices indirectly encourage the sale of these products since they contain few, if any, nutrients and therefore their manufacturing cost is relatively unaffected by fertilizer price.

Treat the soil, treat the seed, treat the crop

Some of these unconventional products are soil-applied, others are seed treatments, while still others are applied postemergence to the growing crop. Some farmers might be encouraged to try one in the belief that while they might not do much good, they certainly can’t do any harm in the small amounts normally recommended. As the saying goes, “It ain’t necessarily so.” Many years ago, a local farmer undertook a dealership of a liquid concoction that was applied to seed corn. He had never tried the stuff, but had read the company literature and it sounded good. He asked my opinion, and after reading the same literature I was unconvinced. We decided to do a simple strip trial on his farm, treating the seed corn in two of the seed boxes on his four-row planter and leaving the other two untreated. The product was supposed to increase germination rate, resulting in faster early growth and increased yield. Our intention was to observe crop performance early in the season and then take yield checks in the fall. We never got around to taking those yield checks because the product burned the daylights out of the seed corn. The check rows looked normal, while the treated rows had terrible plant population, with many of the emerged plants looking really sick. The product indeed was impressive; for a few ounces of it to have that devastating an impact on the seed it must have been potent indeed. For some reason that farmer dealership never really took off.

Liquid fertilizers

I’m not including liquid fertilizers among the foo-foo dust and unconventional soil additives simply because they’re quite conventional in the way they work, but are still worthy of mention. What is unconventional about some, but not all, complete liquid fertilizers is the way they’re sold. (By “complete” liquid fertilizers, I mean those containing all three major nutrients: nitrogen, phosphorus and potassium. Urea-ammonium nitrate solutions and ammonium polyphosphate are common liquid fertilizer products, but only contain one or two major nutrients.) It’s perhaps a generalization, but I’ve found that if complete liquid fertilizer is sold by the ton, the price is usually much closer to that of dry granular fertilizers than if it’s sold by the gallon. That might be because some of these products are so high-priced there would be real “sticker shock” if the price was converted to a per-ton basis. Liquid fertilizers are based on ammonium polyphosphate, which is more expensive to manufacture than either of the products—monoammonium phosphate and diammonium phosphate—commonly used in the manufacture of dry granular fertilizers. When recommended at normal application rates (the amount required to supply a significant portion of the nutrients needed by the crop) liquid fertilizers are conventional soil additives. When recommended at a few gallons per acre (often applied directly to the seed as a “pop-up” fertilizer) as the sole source of nutrients, they’re not conventional at all. Let the buyer beware.

“Unconventional” doesn’t necessarily mean unworthy

To call a product unconventional doesn’t mean it has no value. Some years ago, the agronomists at several of the Midwestern Land Grant Colleges assembled a “Compendium of Unconventional Soil Additives.” A loose-leaf book to make additions and deletions easier (necessary in the ever-changing arena of these products), the compendium consisted of summaries of dozens of commercial products including their claims plus the results of independent crop response trials (usually by university research stations). Most of the products fell considerably short of meeting their advertised claims. Perhaps a product claimed that it was a soil activator and made earthworms dance the fast foxtrot, but when used in accordance with label directions it didn’t perform as advertised. Most fell short, but not all, which is why we can’t generalize. One product when sprayed onto the soil surface was supposed to increase the penetration of rainwater into the soil, reducing the impact of wet spots and decreasing surface evaporation. This product had been around for a while, and in fact I had a gallon of it sitting on a shelf in our chemical storage building. I looked at the recommended application rate and said, “No way would this work.” But, when tested under research conditions, darned if it didn’t do exactly what it claimed. Used at the recommended rate, it significantly increased the infiltration rate of precipitation, just as the label claimed it would.

If it sounds too good to be true …

… it probably is, but if you’re interested in trying one of these products, before you do, ask the sales representative these questions:

1. Is there independent research evidence supporting the product’s claims?

2. If so, are the results available either online or in printed form so you can review them? (Don’t accept one-sentence summaries of university research that are cited in product literature.)

3. Was the research done on any of the crops you grow? (Fruit and vegetable crops sometimes respond quite differently than field crops, such as corn and alfalfa.)

4. Was the research done in or near the region where you farm? (Growing conditions, soil fertility and therefore crop needs in the arid Southwestern U.S., for instance, are much different than in the northeastern U.S.)

If the product passes the above tests, maybe it’s worth trying, even if it is an “unconventional” soil additive. But, if it can’t pass these tests, especially the first two, then maybe it’s foo-foo dust after all, and you should spend your hard-earned crop input dollars somewhere else.

Ev Thomas has worked as an agronomist in New York for 42 years, first with Cornell University Cooperative Extension, then with the William H. Miner Agricultural Research Institute in Chazy, N.Y., including managing its 680-acre crop operation. He continues to work part time for Miner Institute and is now an agronomist at Oak Point Agronomics. He has a written our Forage column for over 10 years and has been an expert contributor on a number of other topics. Comment or question? Visit and join in the discussions.