LOUISVILLE, Kentucky – Putting up silage at the correct moisture content has always been difficult when large quantities are involved.
Running samples through the closest feed laboratory with its carefully calibrated, high-tech near infrared, or NIR, equipment can take hours or even days. By then, the data is old and the silage has been packed into the pit regardless of what the moisture might have been coming off the field.
That’s why serious forage producers, especially dairy producers, have put air dry moisture test systems on the farm that give quicker readings. But those systems still require 45 minutes for an answer, and that’s too long for a farmer who has 10 semi-trailers backed up and the forage harvester sitting idle.
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Even producers who think they can tolerate the 45 minute delay know that it is nothing more than a random sample. It may not be representative of what’s happening in the field and it may not be accurate.
Tim Meister of John Deere outlined the importance of silage moisture levels when he addressed the recent International Conference on Crop Harvesting and Processing, put on by the American Society of Agricultural and Biological Engineers.
“Let’s say you run a 400 head dairy operation, with milk at $14,” said Meister.
“If you were out on your feeding by two percent dry matter per day, it would cost you $50,000 a year.”
John Deere thinks it has come up with a solution. The 2007 series 7000 self-propelled forage harvesters can be bought with an optional on-board HarvestLab NIR system that gives the operator accurate, real-time moisture readings on the chopped crop as it flows through the spout.
Meister said this is the first time a delicate instrument such as an NIR device has been adapted to a rough-service mobile application such as a forage harvester. He said speed is the key component in getting an honest reading on the moisture level of the whole forage crop as it passes through the harvester.
“We take 10 readings per second in the spout,” said Meister. “That information gets logged to the computer once every second.
“So if it takes three minutes to fill a 15 ton truck, you’ll get 1,800 readings of the moisture content in that load. The data shows up instantly on the Green Star display in your cab and you can log it onto your field map.”
He said alfalfa moisture levels that are too high force the crop to ensile with butyric acid rather than lactic acid. This turns the silage sour so cows don’t want to eat it and also lowers its feed value.
Low moisture in alfalfa means the tractors cannot get good compaction. Unwanted air in the bunker causes aerobic fermentation, which lowers the energy level of the silage.
“If you know right away that your alfalfa is too dry, then you know you’ve got a density problem. It’s a simple thing for the operator to shorten the length of the cut so you get better packing. Problem solved.”
Although the same ensiling problems occur in beef feedlots, he said the economic impact isn’t as pronounced as in dairy. The ideal moisture level for alfalfa haylage is between 50 and 60 percent. Corn should be put up as close as possible to 68 percent. Barley is best when the moisture percent is in the mid-60s.
Meister said managing moisture levels is not as easy as it sounds because levels vary depending on changes in sunlight, wind, humidity, field topography and in the trucking distance from field to bunker.
He pointed out several problems with on-farm systems.
“To begin with, you need an exact 200 gram sample. Whether you dry it down with a microwave oven or an air system, you never get it down to a true zero moisture. If you don’t send samples out to a certified feed lab for verification, you could be many percentage points off for a lot of days.
“When you’re working with single samples, you open up so many chances for error. One truck might be from a low spot and it gives a reading that’s too high. It doesn’t give you an honest idea of what the field has. The next truck maybe sat out in the sun over lunch or drove 60 mph (100 km-h) without a tarp so the top layer is drier. Errors are inevitable with single samples.”
The answer, according to Meister, is to take continuous moisture readings of the entire crop as it’s harvested. NIR provides the accuracy, but until now it has been confined to the stable environment of a lab bench in the feed test facility.
Meister, a key developer of the new technology, said his challenge was to find a way to make NIR work in the conditions of a forage harvester.
“We approached the Carl Zeiss Company in Germany. Carl Zeiss has been developing and selling NIR for laboratory use for a number of years. Their stationary NIR sells for about $60,000 and it is absolutely stationary.
“That price was too high for an agricultural machine. Plus we had to have something that was mobile and durable. So we formed a partnership with Carl Zeiss. They developed the NIR sensor hardware to work reliably in a forage harvester spout and we developed all the calibrations, mapping, readouts, yield monitor and other related software. It’s all fully GreenStar compatible.”
One of the biggest challenges was to figure out how to build an optical lens that would not scratch, crack, fracture or in any way distort the NIR wavelength data. If the optics distorted, the information sent to the machine operator would be wrong, and therefore useless.
“With chopped crop flying past the sensor lens at 92 mph (150 km-h), plastics were out of the question. Carl Zeiss had to find something that could stand up to that punishment year after year.
“They finally settled on sapphire glass, the second hardest surface material known to man. Only diamond surfaces are harder. We get no abrasion and no crop sticking to the sapphire surface.
“The HarvestLab is the first mobile NIR and the first NIR built specifically for farmers.”
The same HarvestLab unit used for in-field moisture reading can be removed from the forage harvester during the off season and brought into the farm office for moisture testing throughout the rest of the year.
Because it is fully ISO Canbus compliant, the HarvestLab is compatible with any computer system. It can calculate bunk density, silage shrink and compaction.
“It’s all for the purpose of fine tuning. HarvestLab lets you fine tune your forage harvest so you get the best return on your silage. And throughout the year, it lets you fine tune your feeding operation, particularly in dairy, but also in beef,” said Meister.
The HarvestLab option is expected to be available at John Deere locations that sell forage harvesters. Consequently, it is calibrated for any type of forage crop, including grass, corn, milo, alfalfa, wheatlage and high moisture barley.
The HarvestLab list price is $32,000 US. Because it is ISO Canbus based, it is not available as a retrofit to John Deere forage harvesters built before the latest 2007 model 7000 machines.
For more information, phone Tim Meister at 641-683-2409 or visit
www.JohnDeere.com/Ag.
