So if you are considering what to plant, know that it takes more water to produce grain than a forage crop, so in order to minimize risk one might consider growing forage sorghum for hay or silage in place of a grain crop. Moreover, during periods of drought, hay shortages are often present providing a good market for hay.
If the decision is made to produce a grain crop, management strategies should be altered to minimize risk. Hybrid selection, planting date, fertilizer rates, seeding rates, and weed control
strategies may all need to be altered.
So when considering which hybrid, generally this will be shorter maturing hybrids. With sorghum, not only should length of maturity and drought tolerance be considered, but also try to find a hybrid that produces fewer tillers. These strategies tend to shift more of the available water into producing grain rather than vegetation. Yield potential will not be as high, but the risk of producing little or no grain will be minimized.
Since potential yield will be reduced during a drought, fertilizer rates should be reduced. As a general rule of thumb fertilizer rates should be reduced 25% from what is normally applied.
Also consider applying no more than one-third of the needed N fertilizer preplant. The rest of
the N can be applied as a side-dress application 30 days after emergence. Only apply the sidedress application if the prospect for producing grain is good.
Planting date should be flexible. Do not plant sorghum in dry soil unless you are confident that rainfall is eminent. Wait as long as possible for some precipitation to wet the soil where the seed will be placed. Be prepared to plant immediately following the precipitation event.
Weeds that are drought stressed will be more difficult to control. For this reason using a preemergence herbicide is usually the best option. However, pre-emergence herbicides will require rainfall to move them into the soil or must be mechanically incorporated. If no rainfall occurs within six days after applying the herbicide consider incorporating with a rolling cultivator or harrow. Try not to incorporate the herbicide more than 2 inches. If post emergence herbicides must be used, treat weeds when they are small (less than 3 inches) and are easier to control.
It is very important that seeding rate of sorghum be reduced when experiencing drought
conditions. Reduce seeding rate at least 25% from normal rates. Also consider using a skip row
pattern of only planting ever-other-row or a two-in one-out arrangement. This will tend to allow
the crop to better utilize any available water that may be present in the soil.
Finally, following harvest, tillage operations should be kept to a minimum in order
to maximize precipitation storage in the soil for next year’s crop.
