Well, it’s May Day as I write this and planters were rolling late last week. Dr. Roger Elmore provided an article regarding historical planting progress in Iowa. Finding it interesting, I chose to work the numbers for Nebraska. Many of us have been comparing this year to 2008. When we look at state-wide planting progress, we’re essentially tracking right with 2008: 9% planted the last week of April in 2008 vs. 5% in 2010. It will be interesting to read tomorrow’s report and see the change. In 2008, the average 4 days of good field conditions allowed for a jump in corn planted to 31%. With the size of today’s equipment, and the number of planters going since Thursday last week, I would expect a similar jump state-wide.

I haven’t heard the question yet, but remember receiving it at this time in 2008. The question of “should I switch to a shorter-season hybrid?” The answer is not yet. Unlike soybean varieties which are photoperiod sensitive resulting in reduced yield with later planting, research has proven that corn hybrids can adjust to delayed planting dates.

I found the following information from Dr. Roger Elmore and Lori Abendroth with ISU.  Essentially, research from Purdue and The Ohio State University looked at early (April 25-May 10), mid (May 20-June 1), and late (June 10-15) planting dates to determine the time required (in days) from planting to silking, silking to physiological maturity, and planting to physiological maturity. What the research found was that as planting date was delayed, all hybrids in the study shortened the time between planting and silking. They also found that all hybrids, when planted late, increased the number of days between silking and physiological maturity (but the day increase varied with each hybrid). Finally, they found that hybrids change the length of time from planting to silking more than the time from silking to physiological maturity…so the corn hybrids put less emphasis on the vegetative stages than the reproductive ones. Essentially these findings show that hybrids can adapt to later planting date by changing the number of days to various physiological stages.

How does planting date affect yield and percent risk of frost? I ran some simulations using UNL’s Hybrid Maize model. This model can do many things, but I used long-term weather data from Clay Center, NE to predict potential yields and frost probability based on planting date. Looking at a 113 day hybrid planted April 15 vs. May 1 vs. May 10, the frost risk increased from 10%, 17%, and 21% respectively with average yields in a “perfect year-no limiting conditions” of 248, 254, and 244 bu/acre respectively. For a 110 day hybrid planted the same days, yields ranged from 233, 242, and 243 bu/acre respectively with frost risks of 3%, 10%, and 17% respectively. Granted this is just a model and can’t predict perfectly what will happen.