If this hot, dry weather has been good for anything, it's at least given me an opportunity to kill some weeds this week. This sounds easy enough, but it's not as simple as dumping some chemicals into a tank and taking off across a field. Each herbicide has detailed "do's and don'ts" that we must adhere to. Different rates/concentrations will have different effects in different conditions. Protective clothing must be worn when handling these herbicides, and they often have to be mixed in a certain order when used with liquid fertilizer, adjuvants, or other herbicides in the same tank mix. We use GPS assistance to minimize application skips and overlaps in the field, and keep records that include the time, temperature, and wind speed/direction while making applications.
My first herbicide applications this week were in a large 60+ acre heifer pasture. I used a selective herbicide, primarily targeting pigweed, ragweed, and dog fennel. The weeds showed signs of stress within an hour of being sprayed, and 24 hours later it was obvious they were wilting. Using a selective herbicide to kill weeds removes the competition for soil nutrients, thereby improving the quantity and nutritional quality of the pasture grass (bermuda in this case). Once I finished applying this particular herbicide, I thoroughly cleaned the tanks and sprayer lines as per the instructions on the the herbicide's label.
Today I applied a different selective herbicide on our silage corn crop down in the bottomland. This time it was in an effort to kill and control broadleaf signalgrass, cocklebur, and morning glory. Though it's hard to tell from the photo, quite a few broadleaf weeds have already popped up between the rows. The herbicide I applied should kill them and have enough residual effect to prevent more from sprouting. There are pockets of johnsongrass here and there that this herbicide won't effect, but I can control that with glyphosate in a couple of weeks since the corn is a Roundup-Ready variety.
Speaking of glyphosate, that's likely the next herbicide application on the agenda. We'll either use a minimal- or no-tilling planting technique for our sorghum crop, but first we need to kill all the grasses and weeds that have grown up in the fields. We can't begin the planting sorghum, though, until we get some rain to improve the soil moisture. With that in mind, I probably won't be in any big hurry to get the sprayer back into the field until a couple of days prior to a favorable rain forecast.