Corn Crop Uncertainty

            The Farm and Business section of the DesMoines Register, July 1, 2012, contains a disturbing article. The article, by Dan Piller, is entitled, “Hot Weather During Pollination Could Wreak Havoc With Corn Crop.”  And the title says it all.

            Northeast Iowa, where I live, is often called “the golden buckle of the corn belt.” (When we say “corn,” we mean maize.)  Though the Corn Belt extends from upstate New York to eastern Kansas, a distance of over a thousand kilometers, no part of this region delivers more consistently heavy yields than Iowa.  In recent years, Iowa corn growers have come to expect yields of 180 bushel per acre.  And much of the world has come to depend on this crop.

            But this year, it may be different. Iowa is having a bit of a drought this year and also a heat wave. When this year’s crop was planted in late April, the moisture content of the soil and sub soil was only one third of normal.  With warmer than average temperatures this spring, the corn was off to a good start, and grew rapidly.  The folk wisdom claims that to have a good corn crop, the corn should be “knee high by the 4^th of July.”   This year, most of it will be at least chest high.  But all is not well. We still have not had enough rain.  We have a little shower every week, enough to barely supply the current needs of the crop, but not the soaking rain that would actually recharge the soil moisture level. And even in a year with normal rainfall, it is not unusual to have three dry weeks in late summer.  If there is normal soil moisture, the crop can survive this dry period. 

            When we think of drought, we call to mind images of parched, cracked ground scattered with a few withered and dead plants. Yet today, all the corn fields in Iowa are filled with a lush growth of robust, dark green plants.    If you drove through this area and someone complained about drought, you would say, “What drought?” But it is not certain that this lush growth of corn plants will actually yield ears with a normal number of kernels.

            Besides the lack of moisture, there is another problem.  The hot weather may disrupt the pollination cycle.  When daily high temperatures are above 90 deg f, the male part of the plant (the tassel) may not shed its pollen at the time that the female part (the silk) is able to receive it. The result would be ears with few if any kernels.  

            Ah, with romance, timing is everything—even if you are a corn plant.  The price of corn went up 25% last week, on fears that the crop may be far less than usual. Most of the Iowa crop is sold before it is actually harvested, and some of it is sold before it is even planted.  Usually, when the price goes up sharply, farmers rush to sell any of the anticipated harvest that they have not already sold, so as to lock in this higher price. A farmer I know was thinking of doing this, but after sober reflection, he thought it best to wait and see how much corn he will actually have, before signing any more contracts requiring him to deliver corn.