Corn harvest will be timely this year and with drier grain than normal. Last year, we harvested dry corn as well, and it led to numerous fields with unacceptable header loss. How can you manage against this in order to sell every kernel you produced this year?
To minimize grain loss, it is essential to understand the types of harvest losses and prevention for each.
Pre-harvest loss occurs when ears drop before the combine gets there, mostly as a result of poor nutrition, drought or in some cases, genetics. Pre-harvest loss can be minimized by scouting early and combining those fields where ear drop may be a problem.
Harvest loss can sometimes be substantial. It can be broken down into two types: before-combine and after-combine. Gathering loss includes ears missed or lost by the machine as well as kernels shelled and lost by the stalk rolls or cornhead. Most harvest loss occurs here. Threshing and separating losses are found behind the machine. Kernels not properly shelled from the ear cause threshing loss. Separating loss occurs when kernels are not separated out from the cobs, husks and leaves.
Speed is the key in reducing header loss with dry corn. Ground speed needs to be in correct ratio to roller speed. Plants should be pulled straight down through the header. If plants are leaning forward before being pulled down, ground speed is too fast. Stalks violently flying through the head indicate that ground speed is too slow compared to roller speed.
Deck plate adjustment is also very important. Too wide of a spacing will lead to butt shelling of the ear. Spacing that is too narrow will lead to more leaves and stalks, making it harder for the combine to separate the grain from the trash. The plates should be set to 1/8 inch larger than the average stalk size for the field. On-the-go adjustments have made this easier, but check for wear and spacing before beginning.
Operate your combine at full capacity. Adjust cylinder speed and sieves as needed to separate the grain while at-capacity, and these settings should work for most of harvest. Changes in ear size, plant lodging and kernel moisture may affect the header so be sure to evaluate it more frequently and make changes as necessary.
Ideal corn moisture to minimize header loss and kernel damage is 19 to 24 percent. You have to weigh the cost of drying versus the cost of yield loss due to harvest loss or stalk lodging to make this decision. With the dry weather in most parts of our region, some plants may have cannibalized themselves more than normal this year. With that, stalk lodging could be an issue.
Check for harvest loss periodically throughout the harvest season, not just in the beginning. Two kernels per one square foot are equal to about a one bushel per acre loss. Scout your fields prior to harvest, take moisture samples, and look for dropped ears or signs of stalk lodging. Harvest corn with any issues early. You want to combine every kernel produced this year rather than letting it become a weed in next year’s crop.