As farmers around the state are pulling their combines into fields for the first time this fall, they are finding out that they may not be done dealing with the adverse effects of a dry summer just yet. Many are reporting that the stalks of their corn were severely compromised this year, making it all the more crucial that Mother Nature cooperates this fall and spares us significant weather events that could lead to downed crops.
Stalk rots and stalk lodging are a result of serious crop stress during the grain fill period. Stresses can come from: nitrogen deficiency, foliar diseases, hail, lengthy periods of cloud cover, excessive heat, excessively wet weather, and excessively dry soils, which we experienced much of August and September. The effects of dry soil can be accentuated in fields where root development was restricted earlier in the season, which can occur in areas where crops were planted into less than ideal conditions.
The grain fill period is significant, as the plants prioritize kernel development, while sacrificing the health of other parts of the plant including: stalks, leaves, and roots. Fields at high risk for weakened stalks are fields that did set a decent ear despite being stressed. Hybrids can also vary greatly for stalk quality due to differences in late-season plant health or resistance to remobilization stresses during grain fill.
Significant symptoms of stalk rot may just now start developing, so it is important to scout fields prior to harvest in order to prioritize which fields are more susceptible, in case windy weather does occur, and get those fields harvested first. This should also reduce the temptation of a farmer to let grain dry in the fields rather than in the bins. Stalk integrity can be tested by simply pushing on stalks to see if they are easily collapsible, or by pinching the lower stalks to see if they are easily broken between your fingers.
Another thing farmers are doing as the season comes to a close is estimating their yields. Here is an equation to help you do so with corn: First, let’s break down the field into 1/1000th of an acre. For a field plants on 30” rows, this will equal 17.4 feet. Within that 17.4 feet, count the number of harvestable ears in a row and record. On every 5th ear, count the number of kernels by multiplying the number of kernel rows by the average number of kernels per row. Do this for each ear, and determine the average number of kernels the ears you collected contain. Finally, assign a kernel weight using a factor of 75, 85, or 95 depending on your corn hybrid and its quality. For example, using 85 means that it would take 85,000 kernels to make a 56 pound bushel of corn. Now you are ready to crunch the numbers: multiply the number of ears you counted by the average kernel number and divide it by your factor. For example: 30 ears x 525 kernels per ears divided by 85 is equal to 185 bushel per acre corn.