Understanding Roundup Ready Crops

As a disclaimer, I am not a herbicide expert, have never taken any formal classes or courses on herbicides, and am not in any way associated with any brands discussed in this article.  And as such, this article will be written in lay mans terms.  I do feel I am knowledgeable on the subject but only so far as it has made me successful in using and planting food plots with the roundup ready (RR) traits.

There are really two things you need to know when planting RR crops; and then the details about those two things.

First, RR crops are genetically engineered crops that resist the herbicide glysophate.  The seed you buy can have many different brand names but to be RR they must carry this genetic trait.  For example, this year I planted RR soybeans under the brand name of Jungs (pronounced Youngs).  I have also planted beans under other brand names.  When you go to purchase soybean or corn seed ask your seed supplier if they sell roundup ready seed and go from there.  It is very easy to find seed suppliers in your area by doing a couple searches on the internet.  And regardless of what anyone tells you planting RR seed crops are way easier to deal with than non RR crops—especially for the non-professionals like me.

Second, RR crops have one trait that sets them apart from other seed hybrids—their genetic ability to resist the chemical glysophate.  Glysophate is the active ingredient in many different brands of herbicides that are non-selective herbicides.  Non-selective herbicides kill everything and anything they are sprayed on—except in the instance of RR traited crops.  So, in its simplest terms, crops that are planted that carry the RR trait and are then sprayed with Glysophate will not be susceptible to the chemical but everything else in the field will die (like all the weeds).  You also must understand that glysophate is a contact herbicide—meaning it will only kill weeds it contacts and not the ones that have yet to emerge from the ground.

So now some details:

1.  When purchasing your herbicide, only get herbicide with the active ingredient of glysophate and nothing more.
2. You will be money ahead to buy the herbicide from a farm supplier in bulk form, usually by 2.5 gallon increments.  If you buy the herbicide from the local gardening center it may be diluted and will cost much more.  To know what you are buying a couple things to look for are never buying it pre-mixed, and the %glysophate should be around 41% to say 44% or so.  That means you are buying bulk herbicide.
3. You do not need any fancy additives when spraying glysophate and you should never buy a branded product simply because of the brand.  I have used glysophate under the brand of Roundup, Credit, Kilz-all, and many others.  Each time I go for the best price and that’s it.  Glysophate does not change because of the label on the package and for the food plotter I have never noticed any difference between the generic herbicide with no additives and the name branded herbicide with additives.
4. Now, what are additives?  Additives like surfactants are used to help the herbicide kill the weeds better.  I’m not going to get into the details on how they work but in all the years I have used glysophate, I am not convinced at all that they are worth the $ or the bother.
5. How much glysophate do you put on and how?  First off, always follow the label instructions with any herbicide including the safety precautions.  For me, I have settled on formula I use for all my spraying.  I use 1 quart of glysophate (assuming I’m buying it at around 41-44%) per acre mixed with 7 gallons of water.  This makes my 25 gallon sprayer cover about 3.5 acres.  I simply put in 3.5 quarts of glysophate in the sprayer and fill with 25 gallons.  I use a sprayer with 4 nozzles at about 35psi pressure and can go in 2^nd gear on my 4 wheeler to get the proper coverage.  This will take some practice but once you get it down you can really spray your plots very efficiently.  The nozzles I use are a finer mist than what I have used in the past which gives me better coverage with less water use meaning I need to go back to camp less often to re-fill the sprayer.  To get started, fill your sprayer with just water and go out and spray one acre at a speed you feel gives you good coverage.  If you have nozzles that produce higher flow rates your sprayer will go empty faster.  Make note of your coverage recognizing you want 1 quart of chemical for every 1 acre of coverage.  (For example, if your sprayer goes empty in 1.5 acres and you do not want to change nozzles or speed, you would need to add 1.5 quarts of glysophate to the sprayer each time you fill it up)  For me, nozzles with a finer mist putting out about 7 gallons per acre work the best.  I then add 1 quart for every 7 gallons of water and I know my rate is 1 quart per acre.  1 quart of glysophate per acre has always given me great weed control.
6. In order for glysophate to be absorbed by the plant and work, it does need some time before a rain.  Generally, I like to get at least a half a day for the best kill, although if I’m away from home and know I’m going to get a few hours that hasn’t let me down yet.  Again, some herbicide manufacturers will try to sell you additives or higher priced mixes but in my opinion they are not needed.
7. Timing—If you time your spraying just perfectly you can get by with one spraying per year.  I like to spray about 4-6 weeks after planting.  This gets my crops up and out of the ground but more importantly gets the weeds up and out.  By spraying at this time, I do a good job of killing off the weeds and the soybeans or corn is far enough along that they can possibly canopy over the ground before any more weeds can come up.  It doesn’t always work and a subsequent spraying is sometimes needed.  You can expect to spray twice on new fields that have been planted in pasture ground or crp for example.  Every time you spray make sure the weeds are up at about the just through the ground level to no more than maybe 6 inches or so—and this is just a guideline for the best kill.

To sum this all up remember that RR traited crops do not die when sprayed with glysophate and weeds that are sprayed with glysophate at a rate of 1 quart per acre will die…easy enough?