Hardin County – Hail struck area fields in the county south of Mt. Victory July 27. According to OSU corn specialist Peter Thomison (CORN 2014-25), the impact of hail damage is largely dependent on the corn’s stage of development. Checking the corn earlier this week, the field in question was in the V-10 to V-13 growth stages, which is based on the number of leaf collars on the plant. Because the corn was planted late, it had yet to enter the reproductive stage where pollination occurs and the kernels start to form on the ears.
Hail affects yield primarily by reducing stands and defoliating plants. Loss of leaves reduces the ability of the plant to conduct photosynthesis, which allows for plant growth and development. When the corn plant is smaller, the growth point is at or below the surface of the soil. However, the affected fields near Mt. Victory were further along in the growth process, which makes the plant more vulnerable to hail damage. The hail also did damage to the corn stalks, puncturing and tearing stalk tissue.
Hail damage to leaves usually looks worse than it really is because this time of year shredded leaves and broken leaf midribs still have ability to contribute to plant growth. Because of this fact, plants that are not killed by hail and have not yet gone into tassel will begin to re-grow three to five days after being damaged by hail. It is difficult to determine potential yield loss because of various factors that must be considered.
The planting date will affect yield loss even before considering hail damage. Since corn in this area was planted late due to excessive rains, yield potential was already challenged. Soil types and drainage capacity will also affect the ability for this crop to reach its potential. It is estimated that a field checked in this area showed over 50% defoliation. Based on OSU research from hail damaged crops, this would indicate that we could expect a yield loss of 10-34%, not including yield loss from other factors such as a late planting date.
Soybeans in the same area were checked for damage as well. These plants were in the R3 growth stage, which is beginning pod stage. At this growth stage, soybeans are most affected by hail damage, causing defoliation. According to Laura Lindsey (CORN 2014-25), OSU soybean and small grains specialist, soybeans which show at least a 50% defoliation at this stage of growth will show a yield loss of 9-18%. However, the fields affected by the storm were planted late, so their yield potential will also be affected by a shortened growing season with less light and heat units.
A study was conducted by OSU this past year at the South Charleston branch of the Ohio Agricultural Research and Development Center (OARDC), with soybeans in the same growth stage as the southern Hardin County fields to test the affect of simulated hail damage. In this test, defoliation was 40-45% that resulted in a reduced yield of 62 bushels per acre compared to a non-injured plot, which yielded 74 bushels per acre. These results shows the potential for reduced yields, but cannot be a direct comparison with the fields in question because of other variables.
Although we have had a mild summer with cooler temperatures, soybeans will still produce one to two tri-foliate leaf clusters per week as long as we have adequate moisture and favorable temperatures. Under these conditions in last year’s trial, there was little evidence of defoliation 12 days after the simulated hail damage. Soybeans grown in Ohio will usually adapt to various situations, so it is too early to tell the exact impact that this storm will have on the final yield of the crop. Currently the stems of the soybean plants have about three to five tri-foliate leaf clusters and some upper plant nodes have been broken off, which will affect the final yield of the crop.