Tips and adjustments for efficient corn harvesting

By Andi Anderson

The 2023 harvest season has brought its share of weather challenges, impacting corn dry down and overall crop health. For some regions, premature corn death due to diseases has complicated dry down and harvestability. In such conditions, it becomes crucial to fine-tune combine settings to manage high-moisture corn and reduce harvest losses. Here are key adjustments to optimize your corn harvest.

1. Corn Head Settings: The journey to efficient harvesting starts at the header, where approximately 66% of all machine harvest losses in corn occur. High-moisture corn can present unique challenges, as the ear shanks are often stronger, making snapping more difficult. Wetter corn is also tougher and less flowable through the header. Two major adjustments here are deck plate width and gathering chain speed.
   • Deck Plate Settings: Under normal conditions, set deck plates to 1.25 inches in the front and one-eighth of an inch wider at the back, with a total width of 1 and three-eighths inches. Alternatively, use the third node width of a corn stalk as a reference, adjusting deck plates one-sixteenth of an inch wider at the front. This helps prevent butt shelling and ensures stalk and leaves are pulled through.
   • Stalk Roll and Gathering Chain Speed: Match gathering chain and stalk roll speed to combine ground speed. A rule of thumb is to run gathering chains at 55 rpm when ground speed is 4 miles per hour, maintaining this ratio across speeds. Ensure chain lugs align, and check rubber ear savers for high moisture conditions.
      
2. Threshing Settings: Increased fodder passing through the header can lead to higher threshing losses. It's essential to adjust threshing settings accordingly.
   • Cob Investigation for Rotor and Concave: Preserve cob integrity by setting concaves to avoid breaking cobs into more than two pieces crosswise or lengthwise. Initial concave clearance is typically 3 millimeters over cob diameter.
      
3. Concave Selection: For corn with over 22% moisture, consider using round bar concaves, which maintain cob integrity and grain quality in wet conditions. Extremely wet corn (over 30% moisture) may require round bar concaves to prevent damage.
    
4. Cleaning Shoe Settings: The cleaning shoe is where separation and cleaning take place, especially in wet corn.
   • Sieve Settings: In dry corn, close the lower sieve slightly tighter than the top sieve. For wet corn, open the bottom sieve fully to prevent overloading the tailings auger. Start with an opening of five-eighths of an inch and adjust until the first cob appears in the grain tank, then close one notch.
   • Cleaning Fan: Increase fan speed until all red chaff is gone from the grain tank, then reduce it by 30 to 50 rpms to prevent grain from blowing out the back. Higher fan speed often reduces losses as it helps chaff float, allowing grain to fall through sieves effectively.

Efficient corn harvesting involves checking each area of loss separately: preharvest loss, header loss, threshing loss, and sieve loss. Monitoring these aspects ensures you make the right adjustments for a successful and efficient harvest. Remember, every optimization in your combine settings contributes to better crop yields and minimized losses.

Photo Credit: gettyimages-oticki