Your crop will take up nutrients in either liquid or granular form. How you decide to provide those nutrients is up to you
History, routine and that’s the way it’s always been done. The smartest, most savvy farmers among us are susceptible to ruts, mentally and practically. The liquid versus granular fertilizer debate, if there is one, is, at its core, a question of science, finances, tradition and geography.
Crops need specific nutrients during specific stages of growth. And those nutrients need to be available, whether they exist in granular or liquid form. The conclusion of the agronomist this article references is that the difference between liquid and granular fertilizers is negligible, at least when it comes to yields and crop health. The bigger focus is the four Rs of fertilizer: right form, right place, right time, right rate.
But, there are some considerations when weighing one against the other
With granular fertilizer application, the phosphate granules, or any other nutrient granule, may be too far away from the plant when it needs it most, a problem Richardson Pioneer agronomist Terry Moyer says does not exist when using liquid blends.
“The plant needs nutrients at different stages,” he says. “And when the plant intercepts certain nutrients at different stages, they may not be available, spatially, with granular.”
Granular and liquid both contain and provide for the crop the needed nutrients to survive and thrive, but one main difference between the two has less to do with form than placement and coverage.
Banded, nitrogen and potassium granular fertilizers may burn your seeddue to a higher salt content, Moyer says. And, in other cases, the growing plant will steer its roots away from the nitrogen-banded granules of fertilizer. In starter blends, the nitrogen component may be “too hot” for the plant to access the phosphate granules in the band.
Unlike granular, liquid fertilizer is a homogeneous blend — every drop contains the desired mixture. The granular market knows and understands the benefits of coverage consistency and is steering research and development dollars towards homogeneous blends, Moyer said.
A prime example of this technology coming to the market in a new product is MicroEssentials by Mosaic.
Many agricultural sources say liquid fertilizers contain less salt and, as a result, are the better choice for putting down directly with the seed. The lower salt content limits potential seed burn and tissue damage.
Corn growers often prefer liquid to start their crop, citing reasons of placement, consistency and “pop-up effect” giving corn a better start than any form of fertilizer. Also, corn growers often find alternative, more affordable means (often manure) to top-up nitrogen levels in their fields, making the cost of a simpler liquid formula worth the tank, pump and hose infrastructure worth it. Most planters coming out of the U.S. come ready for liquid.
The agriculture community is close to unanimous in saying the difference are too small to form a conclusion. The Government of Alberta, however, put to test the claim from liquid fertilizer suppliers that their product increases emergence during seeding.
The experiment tested four different openers on four rates of liquid and granular fertilizer on various barley sites. Emergence was not affected. Moyer agrees, but says, “Liquid users will tell you their crops got out of the ground a little quicker,” a sentiment explaining much of why people choose one over the other: Because that is the way they’ve always done it.
The infrastructure needed to handle liquid fertilizer is not extensive, but many farms are already set up for granular fertilizer application. And much of the implements sold in Canada leave the lot ready for granular. In general, “unless you’re setup for liquid, you don’t use liquid.” The costs involved in retrofitting for liquid may not be worth it.
The price of granular is close to liquid, but is often cheaper on a per unit of nutrient measure, when considering a phosphate or sulphur source. Granular is easier to store, and is, at this time, available in a wider range of custom formulations. And, for those considering a switch, yes, liquid fertilizer is readily available, though in less formulations, at most retail outlets.
But, in the end — and to a large degree most agronomists would agree — it comes down to the equipment you already have and the practices that have worked best for you. †