By ED LENTZ

Very little corn has been planted in this area because of the wet conditions this spring. Frequent rains have not allowed soils to dry enough for seeding or equipment traffic.

Ohio State University recommends corn be planted between April 15 and May 10 for optimal yields. Research data has shown that yield loss from delayed planting is about 0.3% per day in early May and 1% per day by the end of May.

Yield losses may be attributed to a shorter growing season, a greater risk for disease and insect damage, and a higher risk of pollination failure, caused by hot and dry conditions.

However, late plantings are not always associated with lower yields.

Allen Geyer and Peter Thomison, Ohio State University corn extension specialists, recently discussed how delayed plantings have affected state corn yield averages in the past. I have adapted their information in the following discussion.

For the purposes of this discussion, “late start” years are those in which 40% or more of the Ohio corn acreage was not planted by May 20.

Since 1980, there have been significant planting delays associated with wet spring weather in 11 years — 1981, 1983, 1989, 1995, 1996, 2002, 2008, 2009, 2011, 2014 and 2016.

Of these 11 years, the greatest delays in crop planting occurred in 2011, when only 19% of the corn acreage was planted by May 30. In 2011, most of the corn in Hancock County was planted in early June.

Even with the planting delay, 2011 yields were good because the rest of the growing season was ideal. Warm June soils allowed for quick germination and emergence, timely rains fell the rest of the summer, and a killing frost was about a month later than normal.

However, 2011 was also the wettest year on record at the time, and no surprise, Lake Erie had a record algae bloom.

In five of the 11 years (1981, 1983, 1996, 2002 and 2008) average state yields were markedly lower than the state average yield of the previous five years. In six of the 11 years, average yields were five bushels per acre or more below the yield trend line for Ohio.

In one of these years, 2002, the average corn yield dropped to 89 bushels per acre (nearly comparable to the record low of 86 bushels per acre for the major drought year of 1988). For Hancock County, the corn yield average was 55 bushels per acre in 2002.

However, in six of the 11 years, yields were similar or higher than the statewide average yield of the previous five years, and in one of these years, 2014, a record high corn yield, 176 per acre, was achieved.

In 2014, Hancock County had a record average corn yield of 193.3 bushels per acre, a record that still stands.

In 2017, 73% of the corn crop was planted by May 20 (which does not categorize 2017 as having a “late start”). However, agronomists estimated that as much as 40% or more of the corn planted in late April of 2017 was replanted in parts of Ohio due to excessive soil moisture.

Nevertheless, the statewide yield in 2017 was a record 177 bushels per acre, 16 bushels above the yield trend.

This comparison of statewide average corn yields from past years indicates that lower grain yields are not a certainty with late planting. While delayed planting may cause yield loss relative to early planting, planting date is just one of many factors that influence corn yield.

When looking at Ohio corn production, planting date has not been a strong indicator for grain yield. Other factors that occur the rest of the growing season will determine the final yield.

Weather conditions (rainfall and temperature) in July and August are probably the most important yield-determining factors. Favorable weather conditions subsequent to planting may result in late-planted crops producing above-average yields as was the case in 2009 and 2014 (and 2011 for Hancock County).

However, if late-planted crops experience severe moisture stress during pollination and grain fill, then crop yields may be significantly lower than average, with 2002 being the most notable example.

Farmers are anxious to get this year’s crop planted. Anxiety from uncertainty will greatly increase if they are unable to plant by Memorial Day. Please be considerate of your farm neighbors as they cope with this stress.

Also, be aware of farm equipment on the rural roads as farmers will race to get their crop planted once field conditions improve.

Lentz is extension educator for agriculture and natural resources for the Ohio State University Extension Service in Hancock County. He can be reached at 419-422-3851 or via email at lentz.38@osu.edu.

Lentz can be heard with Vaun Wickerham on weekdays at 6:35 a.m. on WFIN, at 5:43 a.m. on WKXA-FM, and at 5:28 a.m. at 106.3 The Fox.

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