When spring soils remained cold and wet, and never seemed to warm up and dry out, what were your expectations for the 2008 corn crop? When Mother Nature never was able to get the faucet turned off, what were your expectations for the 2008 corn crop? When the weather finally began to cooperate about the time you would normally begin harvesting, what were your expectations for the 2008 corn crop? It’s time to pull up a chair by the kitchen stove and revisit a year that has left everyone scratching their head.

When your bags of seed corn had been sitting in the machine shed gathering dust and bird droppings until mid-May, would you have bet the farm that 2008 would have provided one of its highest yields? Probably not, but that is what happened for many Cornbelt farms. Iowa State agronomists Roger Elmore and Lori Abendroth report the third best yield on record, but some frustrated farmers still are trying to harvest the last 6% of the crop. In their analysis of 2008 they say the year certainly started with low expectations.

In Iowa, as has been the case across most of the Cornbelt, corn planting has gotten progressively earlier each year, and most planters head to the field 2 weeks earlier than they did 30 years ago. Curiously, 2008 saw corn planting begin about the time it did in the 1970’s and did not finish until the first of July, in part because of the need to replant 11% of the acreage. Elmore and Abendroth recommend having corn planted by May 10th in Iowa, but only half of the state was planted by May 15th. A result of the late planting and significant replanting was the fact that farmers intended to plant 13.3 million acres, but will only be harvesting 12.5 million. That loss is second only to the 1993 flood year when acreage was reduced 8.3%.

But once the corn was in the ground, heat units remained well behind the average and statewide for Iowa, there was an average of 125 degree day departure from normal between May 1 and October 16th. While long term records don’t exist for silking, the Iowa State agronomists report 2008 was the slowest compared to the past few years, and 50% of the corn was silking 15 days past the two prior years. That told them to expect a late harvest, and true to form it was not until November 5th when 50% of the corn had been harvested. Despite the late planting, silking, and harvest, the average yield of 172 bushels per acre is 4 bushels above the trend line.

So why was there such a diamond in the rough? Elmore and Abendroth used a computer model of how weather affects corn, beginning with the late planting date, and inserted all of the weather data for the past 22 years. Not used were diseases, insects, weeds, soil compaction, hail, lodging, and non-weather factors. They found that 2008 had the second highest potential yield, and followed only 1999. The computer model calculated weekly yield potential, “Because late season weather was conducive to higher yields, the projected yields continued to move upward from what was predicted earlier in the season,” they said. In other words, the key to the 2008 success was the late season weather. Although silking was late, temperatures were cooler and rainfall compared to the best of years. That allowed slow crop development, and a long period for grain to fill, fortunately without a killing frost.

Summary:
2008 corn yields turned out better than anyone would have expected given the start on the year that was cool and wet. However the late planting meant corn silked later in the summer and with the help of cooler temperatures and ideal rains, corn matured slowly and thoroughly despite the late date on the calendar. An early frost would have brought the process to a halt, but without that factor, corn was maturing and drying well past the time that corn has usually been harvested in most recent years.

That is what Roger Elmore and Lori Abendroth at Iowa State think. Maybe you have more to add to the discussion. Pull up a keyboard and tell us!