23 Sep Sorghum Harvest Aids
Sorghum Harvest Aids
Sorghum harvest for early planted fields are underway and looming in High Plains. Over the past 10 years harvest aid use in grain sorghum has steadily increased and is on more and more growers’ minds.
Josh Lofton at Oklahoma State University put together a very comprehensive guide (PSS-2183) on this subject. The common questions are normally “What harvest aid chemical should I use?” and “When should I apply it?”
To answer the “What to apply” there are three compounds that are registered for use in sorghum: sodium chlorate, glyphosate, and carfentrazone. Sodium chlorate is a true desiccant, meaning it will kill the leaves, but not the rest of the plant, so regrowth can occur if conditions are right. Sodium chlorate can be an effective late season grass weed control product. In most cases, glyphosate is the herbicide of choice. It is readily available and is quite inexpensive. Glyphosate is excellent at drying down the sorghum plant and an excellent late season weed control option. Glyphosate does kill the entire plant, so there will be no regrowth. Carfentrazone is a broadleaf herbicide and is very good at controling late season weeds. It will also desiccate and terminate the sorghum crop.
When to apply these harvest aids really has a two part answer. The first relates to when the crop can be terminated an not affect yield. Since sorghum heads flower from the top down, you want to check for black layer at the bottom of head. This is important because if you spray too early, you can reduce yields. In most cases using black layer on the bottom of the head as a key is too early and the grain is too wet. The best method is monitor your grain moisture and begin the first wave of harvest aid chemical applications when grain moisture is approximately 30%. There are a couple of things to keep in mind. The first is that there is a 7 to 10 day pre-harvest interval for these three chemicals. Always read the label. The second part is that if you are using glyphosate and killing the plant completely, lodging can be a problem if you leave the desiccated crop in the field too long. Growers with lots of experience in desiccating sorghum often apply harvest aids to the number of acres they believe they can harvest in a 7 to 10 day period. This means that you will likely be applying harvest aid chemicals at a 3 to 5 day interval across the season.
Harvest aid chemicals can speed up sorghum harvest and grain dry down. They can also be an effective way to control late season weeds.