This tip was provided by:
Calvin Trostle, Extension Agronomy, Lubbock, 806-746-6101, firstname.lastname@example.org
Grain Sorghum & Hail Injury Assessment
It is that time of year when the rain we so often need is accompanied by hail. Corn hail injury assessment resources are more readily available than grain sorghum, but there is literature published to help producers with initial assessment in terms of what yield losses might be for grain sorghum as well. I have looked at several fields over the years that the degree of sorghum leaf loss looks devastating (and it is), but in fact, the yield potential may not be reduced that much.
An older Texas Extension document entitled “Assessing Hail and Freeze Damage to Field Corn and Sorghum,” (EB-6014; available for free download at http://www.agrilifebookstore.org ) provides some simple tables that estimate grain sorghum yield reduction due to leaf loss (most of the document is about corn, but see page 6 for grain sorghum).
Crop insurance industry guidelines are more complex and will look at stand reduction, stand reduction due to hail, leaf loss, and grain loss in headed sorghum after soft dough. Those methods are more detailed and probably beyond what most producers need. If you would like to learn more about these other stages of hail damage on grain sorghum, Univ. of Nebraska Extension summarizes the losses in document EC129, “Evaluating Hail Damage to Grain Sorghum,” which you can read/print/download from http://extensionpublications.unl.edu/assets/pdf/ec129.pdf
For the leaf loss in grain sorghum, AgriLife’s EB-6014 two key tables are as follows:
Table 3 is for younger grain sorghum is generally intended for pre-boot sorghum (~70 days in much of Texas would be after flowering for a medium maturity hybrid in the High Plains.
For early assessment of grain sorghum hail damage you may initially think that it looks really bad, but often the damage is not as bad as it looks. The earlier the leaf loss, then impact on yield will be less. Many hail-damaged fields are often “keepers”, just let it grow. (Fungicide applications to prevent opportunistic fungal infections are probably not merited.) For young sorghum before about leaf stage 7, the growing point is still below the soil line thus near total leaf loss has only a small reduction in yield potential. Using Table 3 above, here is an example that requires us to estimate potential leaf loss:
Medium maturity hybrid (half bloom about 65 days in much of Texas) has a 50% leaf loss at 45 days. Those numbers aren’t on the table, but by splitting the losses at 30 and 60 days and plant age of 37 and 51 days, I estimate that the potential yield loss would be about 15%. That is a stand you would keep. Unfortunate, but not devastating.
If you have hail damage but need assistance, contact us at Texas A&M AgriLife. Even field pictures of typical plants can help us assess initially the status of the field and what grain yield potential remains.