Corn in Mississippi
How much yield loss should I expect from hail damage?
Corn grain yield reduction resulting from hail damage is dependent on corn growth stage and the amount of defoliation. Yield reduction from hail damage follows a parabolic pattern to corn growth stage with the apex occurring at the tassel stage. Corn is most sensitive to defoliation at the tassel stage because all leaf tissue is exposed and grain development has not started.
Corn
is most susceptible to defoliation at tassel because vegetative development
is complete when tasseling occurs. Grain yield suffers because the production
of photosynthetic energy is reduced proportional to the extent of defoliation.
Embryo development of newly pollinated kernels is extremely dependent
on photosynthetic rates during pollination. Vegetatative and reproductive
plant parts compete heavily for current energy supply immediately after
pollination. Thus, constraints (hail damage, water stress, nutrient deficiencies
etc...) limiting photosynthetic rates during this time period will cause
significant yield loss in the form of kernel abortion. Kernel abortion
will begin on ear tips and proceed toward the base of the ear depending
upon severity.
Research studies have shown corn grain yield reduction from hail damage at the tassel stage nearly correspond with percent defoliation. Thus, 50 and 100 percent defoliation at tassel stage usually reduces yield about 35-40 and 90-100 percent, respectively. Corn at the brown silks to blister stage is slightly less susceptible. Expect about 10-15 percent yield loss from 33 percent defoliation; 25 percent yield loss from 50 percent defoliation; 50 percent yield loss from 75 percent defoliation; or 75-90 percent yield loss from 100 percent defoliation.
Few if any management inputs exist which might alleviate effects of hail damage. Supplemental fertilizer or water beyond normal requirements will likely not achieve a positive economical effect. Transpirational demand for water and nutrients should actually be reduced, because of the defoliation of leaf tissue. Therefore, normal management practices should be utilized if the crop is intended to be salvaged.