As I surveyed the county on July 6, 2010, the amount of water that was still moving from west to east toward the Gulf was amazing! Rainfall amounts from Alex range from five to more than 9 inches. Mature sorghum took a hit from this excessive rainfall event. Fields of mature sorghum have grain dropping from the heads to the ground in an alarming rate in some locations.
For the most part this is what is occurring, the grain drop is being caused by the grain kernel sprouting, the radicle (sprout) is pushing against the glume, forcing the grain to fall. There are some differences between hybrids, some have tighter glumes, and the other big difference was the stage of maturity at which the grain was during the big rains.
So the big question is, how much yield loss are we going to see from this grain drop? Here is a method to calculate your potential yield loss as it relates to grain on the ground. Depending on seed size, 16 to 21 seeds per square foot represent a loss of one bushel or 56 pounds per acre. So take several random counts in a given field, on a square foot measurement, and this will give you some idea of what you might expect regarding yield loss from grain on ground.
