This trend was first evident at the National Farm Machinery Show in Louisville, Ky., in February. Now more companies are following the lead. Sprayer companies are either incorporating chemical injection systems into their new sprayers for next year, or offering it as an option. Companies that already offered it are fine-tuning the systems.
It's a case of companies responding to a demand in the marketplace. Glyphosate ruled for more than a decade, but weed resistance to glyphosate and other products, plus the threat of Palmer amaranth, a giant among weeds, has caused people to move back toward residual herbicides in addition to a post-application.
Since more people are using residual herbicides, usually more than one, it makes sense to inject them directly into the water stream coming out of the sprayer tank, carrying only water, before the product enters the booms. Some companies power the injection system with one pump, some companies use more than one.
What injection vs. mixing in the tank does is eliminate issues with products that settle out if you're stuck with a batch or partial tank of chemical spray overnight due to a rain-out or other type of situation. The chemicals aren't mixed together until an instant before they're sent out into the boom.
The bigger issue, perhaps, is preventing crop injury and contamination. For whatever reason, this was a tough spring for chemical injury due to tanks that weren't thoroughly cleaned after spraying glyphosate and then switching to residuals. It can also work the other way, depending upon what residual you put in the main tank and what crop you are spraying next. Apparently glyphosate is an effective tank cleaner by itself.
With injection you don't ever have to put chemicals in the spray tank if you don't want to, depending upon what products you're spraying. It's a concept that is drawing enough attention that sprayer makers are responding.