Chopper adjustments pay big dividends
|By Adam Verner|
As summertime comes to a close, there is usually a different buzz on the radio. I’m not talking about on your Sirius or FM dial. I’m talking about all of the chatter that will be on the CB radios for the next few months during harvest season.
For most livestock and dairy producers, corn silage harvest can be considered the single most important time of the year. Whether you use a custom harvester or your own chopper, making sure your corn silage gets put up at the right stage of maturity and moisture and is processed correctly are very important. Putting up a mediocre crop of corn silage could be the difference in purchasing thousands of dollars of unnecessary supplemental feed or having less milk in the tank.
One part of this silage process has taken years to become relevant — kernel processing. Most people are now aware of the Corn Silage Processing Score (KP score). The KP score is basically how well the corn silage, mainly the corn kernel, is processed during chopping.
The more processing, tearing, and pulverizing of the kernel you can get the better. This is why the setup of your forage harvester and its kernel processor can be the difference in great silage and average silage. The optimal KP score is 70 or above. An adequate score is from 50 to 70, and below 50 would be considered poor kernel processing. Most of the new choppers purchased today can be properly set up and adjusted to achieve the optimal 70-plus KP score.
I have made a checklist of the places to check on your forage harvester to ensure you are doing everything you can to produce excellent processed corn silage.
Keep knives sharp
To me, it all starts with the corn head. Make sure your knives are sharp and all adjustments have been made for optimal crop flow to the feed rolls. Be sure you check the springs or whatever your harvester uses for feed roll tension. The precompression of the crop before it gets to the cutting drum is key for the best and most consistent chop quality. Sharpen the knives on the cutting drum at least once per day. Dull knives lead to poor chop quality and make your chopper work a lot harder in the process.
Another critical step in producing high-quality feed is making sure the shear bar is properly adjusted. I recommend that this be adjusted in the morning after knife sharpening and at least one more time during the day. At minimum, adjust the shear bar twice per day.
One other adjustment that often gets overlooked is the drum bottom. The floor beneath the cutting drum has a huge effect on the crop flow and how far you can blow out of the spout. Check this adjustment every time you change out the knives. You can find the proper spacing for these adjustments in your operator’s manual.
Properly adjusted and aligned KP rolls are essential in the crop flow process and can be the source of many plugs. The ideal alignment occurs when the crop hits the lower third of the top roll. This ensures continuous crop flow and is crucial to the differential speed of the rolls as well. Many KPs run at a 30 percent differential speed, meaning that the top roll is turning 30 percent faster than the bottom roll. This leads to the tearing and slicing of the leaves, cob, and kernels. Changing your differential speed may change the way you chop and process your corn this year.
Stop and check
The KP gap spacing is also critical. The gap distance is going to vary by machine, brand of rolls, hybrid, and the silage end user. Some operators run their KP gaps as close as they can, 0.5 millimeters (mm), while others are over 3 mm. This is where it will take time and testing to figure out what gap spacing you should be running in each field and for a particular hybrid.
Do not be afraid to stop the cutter, exit the cab, and check what is coming out of the spout. You should not find any whole kernels in a 32-ounce cup sample of fresh silage. If you are finding several whole kernels, then you probably need to look at tightening up the KP.
Before the season, also check the calibration of the KP gap to make sure what the monitor in the cab reads is the same gap the KP is set to. I also recommend at least once per week or every knife change to inspect the KP rolls for any damage or excessive wear. You can have everything set and adjusted perfect, but if the rolls are worn out, you will not do a good job of processing.
This may seem like a lot, but a few hours spent properly adjusting your cutter can lead to higher feed quality in the pile and a lower cost of the feed in the feedbunk. So, before you go out and spend tens of thousands of dollars on new KP rolls this season, stop and check to make sure that your cutter is properly adjusted first. You just may be surprised as to what your current chopper and rolls are capable of! Be safe this harvest season!
This article appeared in the August/September 2016 issue of Hay & Forage Grower on page 24.
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