Statewide
Sodium chlorate and glyphosate are labeled for pre-harvest use in grain sorghum. The former is a burn down chemical that acts as a defoliant, whereas glyphosate (technically labeled for weed control) kills the plant which aids in drydown. For seed milo growers, diquat dibromide is also labeled. Although limited Texas AgriLife research has not demonstrated yield differences among treated and untreated grain sorghum, the ability to manage and potentially accelerate harvest can have significant advantages in Texas, especially when humid conditions slow drydown. Furthermore, combine operators have often noted that the uniform condition of the crop at harvest makes use of these harvest aids a plus. The primary physiological criteria for application include seed moisture below 30% AND physiological maturity, which is best determined by identifying black layer in the seed (Figure 1).
For a summary of grain sorghum harvest aid uses in grain sorghum, whether this may be an appropriate management tool in your farming, as well as links to Texas AgriLife guidelines, consult Nueces Co. ag. agent Jeff Stapper’s blog at http://cbagbriefs.blogspot.com/2012/06/preparing-grain-sorghum-for-harvest.html.
Figure 1 (below). Sorghum kernels in various stages of maturity harvested from the same head from the most mature (1) to the least mature (5). The black layer is first readily visible in (3) and becomes more distinguishable as the seed loses moisture. Do not confuse black layer, which develops where the seed is attached to the plant (bottom end when in the head), with the black dot on the opposite end of the seed.
