It’s a late harvest this year. The combination of corn and soybeans being planted later than normal last spring, and the cool summer weather, pushed the start of harvest into October. Outside of the later planting, it was another good growing season, with plenty of rainfall during the critical growth period in July and August.
Heading into the final stages of the growing season, farmers were keeping a close watch on the weather forecast, particularly the temperatures. Mid-October was the average date for the first frost in Peoria County. Farmers were hoping for a frost-free season into late October this year.
Soybeans are very susceptible to temperatures much below 32 degrees Fahrenheit. The tops of soybean plants are easily damaged with temperatures in the 30-to-32 degrees range, and a night in the high twenties will end the growing season for soybeans, as it would completely kill the leaves and stems of the plant. As a general rule, soybeans that are planted in narrow rows (six to 15 inches apart) are slightly more tolerant of light frosts, as the thick canopy holds the soil heat better. Will this affect yields? It will if the soybean plant is still green. If the plants are maturing and turning yellow, the damage will be much less.
An early frost would also affect the corn crop. Corn kernels continue to accumulate weight until they reach physiological maturity. This is signified by a “black layer” where the kernel is attached to the cob. An abscission layer forms when a hard starch layer reaches the kernel base. This layer is black or brown. The abscission layer has cut off water and dry matter transfer from the kernel. At the black layer, kernel moisture is 28 to 35 percent. Corn is dry and can be stored at 15-percent moisture.
Black layer normally occurs 60 days after the corn tassels. Tasseling signals fertilization and the beginning of a kernel. Thousands of tiny pollen grains originate from the tassel and fall on the silks located midway between the root of the plant and the tassel. A pollen grain attaches to the end of each silk. It travels inside the silk and finally reaches the base of the cob, hence the beginning of a kernel of corn.
You may have heard that Peoria-area farmers grow No. 2 yellow dent corn. “Dent” is another of those farm terms that you may wonder what it means. Approximately 20 days before the corn kernel reaches black layer or physiological maturity, it dents. Hard starch begins forming at the kernel tip when denting occurs. The hard starch layer gradually progresses to the kernel base during the next 20 days as the kernel approaches maturity. If you look at a kernel of No. 2 yellow dent corn (not sweet corn from a grocery store or farmers market), you will see that the end of the kernel has a small dent or indentation in it. That’s the “dent” in No. 2 yellow dent corn.
Please be careful when traveling rural Peoria County roads this fall, as it’s going to be an extended harvest season into November. Another good harvest of corn means more trips from the field to the farmstead or local grain elevator for storage. It’s this grain that’s going to be fed to livestock, processed into grocery products and ethanol, and exported to other countries. That translates to cheap food on your table, competition for oil companies and lessening our trade deficit with foreign countries. iBi