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Pull-type forage harvesters dominated how silage was chopped in the 1980s.
Forty years of forage equipment progress Editor’s note: Kevin Shinners has been an influential voice, inventor, and researcher during his 40-year career at the University of Wisconsin-Madison. Here, he looks back and chronicles the changes in forage equipment that have taken place during his career while also eyeing the future. by Kevin Shinners
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N MANY ways, hay and forage equipment remains fundamentally the same as when I began my career 40 years ago, but today, equipment is more sophisticated, intelligent, and productive. In the next 40 years, engineers will continue to pursue new machine forms and adopt technologies to make hay and forage harvesting even more efficient and productive.
Cutting and conditioning The biggest change has been the shift from sickle to disc cutterbars. Throughout the 1980s and 1990s, there was a steady move toward disc cutterbars. Now, sickle cutterbar machines are almost extinct. Much greater productivity has more than offset the greater expense of the disc mower-conditioners. End-wise transport now facilitate cutting widths up to 20 feet. In 1981, windrowers had less than 80 horsepower (hp) and a conditioner and cab were not even standard. Today’s windrowers exceed 200 hp and can easily cut up to 20 acres per hour. Trac-
tor-mounted, wide-area mowers now offer cutting widths in excess of 34 feet and can harvest over 35 acres per hour — more than four times the typical productivity of a windrower from 1981. Guidance systems on tractors and windrowers have helped reduce fatigue and improve efficiency. Mower-conditioners are good candidates for autonomous operation, so we could see fleets of smaller width, electrically driven, autonomous mower-conditioners in the future. Slow, inconsistent drying continues to frustrate hay producers. Despite much development effort, engineers have never been able to make substantial improvements to conditioners and hay drying. Current development efforts to enhance drying rates are limited, so we likely won’t see major improvements in this area in the near future.
Harvesting and storage Forage harvesters still perform the same basic machine functions as 40 years ago, but the market has strongly migrated from pull-type to self-propelled machines. In 1981, there were nine manufacturers of pull-types, and
now only two manufacturers remain. Self-propelled harvesters have grown immensely in size and complexity. The largest machine in 1981 had 325 hp and could harvest six rows. Current machines approach 1,000 hp and can harvest up to 12 rows. The introduction of the kernel processor (KP) in the late 1990s was a game changing development. This mechanism enhanced ruminant starch utilization and allowed longer length-of-cut to enhance effective fiber from the stover fraction. There is no doubt that the KP helped accelerate the greater use of corn silage in the dairy ration. Forage harvesters have not only increased in size but also sophistication. Near infrared reflectance spectroscopy (NIRS) technology now provides on-board accurate estimates of moisture content and forage constituents. Combined with mass-flow sensing, forage yield maps are possible. Bacterial inoculants can be accurately applied to enhance fermentation. Sensors and controls now guide the machine path and direct the spout to uniformly fill the transporter. None of these technologies were remotely possible in 1981. Since forage harvesters unload continuously, autonomous harvesting will be challenged by the need to manage both the harvester and the continuous fleet of transporters that also need to be moved from field to storage via roadways. Improved fiber digestion from advanced processing systems is being investigated, which could fundamentally change how forages are harvested. In 1981, the tower silo dominated the way we stored ensiled forages and there were an amazing 16 manufacturers selling forage blowers. Today, many tower silos stand as empty monuments to a bygone era. Bunk and bag silos dominate because of greater productivity at filling, lower capital and operating costs, and less daily aggravation. These storage systems helped expedite the adoption of
KEVIN SHINNERS The author is a recently retired professor and agricultural engineer from the University of Wisconsin-Madison.
10 | Hay & Forage Grower | April/May 2022
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