Herbicide premixes frequently offer several advantages to the producer; however, keeping track of premix components and their ratios can sometimes be difficult. For the past several years, we have printed a table of corn herbicide premixes, as well as a table of soybean herbicide premixes, in the Bulletin; this year is no exception. Table 4 and Table 5 list most of the commercially available corn and soybean herbicide premixes, respectively. The application rates listed in the tables are meant to be used as a reference; for some of these herbicides the application rates will vary depending on soil texture, organic matter, weed species and size, and so on. Always consult the respective herbicide label for appropriate application rates.|
But what if you are interested in an application rate different from that listed for a particular herbicide? With the information presented in these tables, it's relatively simple to do the calculations for your rate of choice. We'll do an example calculation to make it easier to understand.
We'll work through an example with a dry premix formulation, Canopy XL 56.3DG. According to Table 5, 1 pound of Canopy XL 56.3DG consists of 0.469 pound of sulfentrazone active ingredient (a.i.) and 0.094 pound of chlorimuron a.i. However, instead of a use rate of 6.8 ounces, you want to know how much active ingredient of each component is contained in a 4-ounce use rate.
Converting 4 ounces to pounds gives us 0.25 pound of product applied. Next, we calculate how much sulfentrazone and chlorimuron a.i. are applied in 0.25 pound per acre of Canopy XL 56.3DG:
Finally, we can also determine product equivalents based on these active ingredient amounts:
--Aaron Hager and Christy Sprague