Farm Horizons, August 2007
A look at the dry summer
By Dave Schwartz
The past two growing seasons have been unseasonably warm and dry. Currently, growing degree units are approximately 10 percent above normal.
This year, at our home south of Litchfield, it seems to be particularly dry, so I had to find out just how dry. I checked with our local Soil and Water District in Litchfield.
Our neighbors, Harry and Marilyn Swanson, record rainfall for the district, so I got their rainfall totals for the growing season beginning May 1. The Swansons’ total for the month of May was 1.8 inches, with the largest rain .35 inches.
June, which is normally the wettest month, came in at only 1.43 inches, with the largest rainfall of .36 inches. July has been even dryer than the two previous months, with six rains totaling .31 inches through July 23.
The combination of above-normal temperatures and below-normal rainfall has put our crop under severe stress. While traveling around the countryside, I have noticed how some fields tend to handle the stress better than others. In some cases, the difference is so visible. Why?
I believe several factors are involved. In some cases, I’m sure soil compaction plays a role. Fields may have been worked too wet at planting time and this compaction is now affecting root development. Take a spade to these fields and you will find a hard compacted layer usually three to six inches deep. It’s nearly impossible to penetrate through this compacted layer with a spade.
Weed control is another factor that is critical in drought years. Good weed control pays dividends in years like 2007.
Another possibility is the corn hybrid. Hybrids with strong root systems stand out in drought years.
Stress may be caused by corn rootworm, too. Rootworms are gradually adapting to the corn/soybean rotation that has been used for so many years. If corn is lodging and showing signs of moisture stress, corn rootworm is likely the cause. This will be a good year to compare corn rootworm hybrids to corn rootworm insecticides.
On the positive side, I have had maybe 20 mosquito bites the whole summer, and have enjoyed many bug-free evenings on our porch.
My hope is that we break out of the drought cycle soon so there is ample time to replenish soil moisture before fall freeze-up.