As combine headers get wider to feed the growing appetites of the monster combines available today, uniformly spreading straw and chaff is increasingly challenging.
While there have been some improvements in combine choppers and spreaders recently, most combines available in the U.S. still struggle to evenly distribute straw and chaff wider than 30-35 feet. In fact, some struggle to spread lighter residue wider than 25 feet.
Poorly distributed residue presents numerous challenges to conventional tillage and no-till systems alike. Heavy bands of residue warm up more slowly in the spring, causing streaking within early emerging crops. The soil under heavy bands of residue also dries slower, making planting more difficult because it becomes a challenge opening and closing the seed slot.
Stripper headers offer one solution to many small grain residue distribution challenges. Stripper heads were introduced in Kentucky in the early 1990s and have become a popular part of the state’s small grain production systems. They are also gaining momentum in Kansas, Colorado and the Dakotas.
Stripper heads mount to existing combines and utilize a 24-inch diameter rotor with 8 rows of fingers, delivering it into a cross auger. The rotor spins at 500-800 rpm as it combs grain and some chaff from the straw. The end result is most of the residue remains firmly attached to the soil, as uniformly as it was seeded.
Because most of the straw doesn’t enter the combine, it increases combine capacity, reduces fuel costs and eliminates the need to spread most of the residue with the combine. University and independent research from Colorado and other states concludes that soil moisture retention is significantly increased with a stripper head, which results in higher crop yields. Stripper heads up to 32 feet are now available. These larger widths work very well with larger combines, particularly with the units that struggle most with residue distribution.
Most combines sold in Europe are outfitted with high-performance choppers and chaff spreading systems compared to what’s generally available in the U.S. Uniform harvest residue distribution is given more emphasis in Europe. In many cases, combine purchasing decisions are made based on the machine’s ability to finely chop and uniformly distribute straw and chaff across the working width.
To achieve rapid decomposition of the ever-increasing quantities of straw and chaff that result from higher crop yields, the combine must ensure short chopping and uniform spreading. For this reason, most combines sold in Western Europe are equipped with electrically adjustable tailboards or electrically adjustable deflectors.
Such additions allow the operator to make adjustments to both the overall spread width and the direction of material discharged from the chopper. These systems are particularly effective when working on side slopes, with varying crop moisture levels or when operating in windy conditions.
For example, if the combine is working in a strong side wind, the operator can make adjustments using cab-mounted switches to change the direction of the tailboard fins and direct more material into the wind. When it’s works directly into a strong head wind, the chopper-spread pattern can be increased, again to help distribute residue as evenly as possible.
Companies, including the German manufacturer Claas, offer Lexion models in Europe that come standard with electric switches to adjust residue-spreading direction, plus engage or disengage the straw chopper. The same models also use a fan principal to blow chaff into the stream of straw to aid spreading. On many combines, such a system allows the producer to spread chaff and windrow straw for baling purposes, a feature frequently requested by growers in some areas of the U.S.
The New Holland CR9090 delivers a maximum of 591 horsepower and also features a high-performance straw chopper with an optional Opti-Spread system that mounts behind the chopper. This system features two spinning discs to help neutralize side-wind or hillside impact. For total operator convenience and uninterrupted fieldwork, the adjustments are fully cab controlled offering two pre-set memories for easy adjustment both within the field and across the end rows.
We can expect combine capacities to increase beyond the currently available Class 9 machines. These will be best utilized by larger producers who are currently operating 2 or 3 combines because it allows them to reduce the number of machines required and result in lower labor requirements.
Along with larger combines will come larger platforms. Currently, 16-row 30-foot corn heads are available together with 45-foot grain platforms. How much bigger will headers get? On rolling ground, some would suggest that they are as big as they can get now, but there are many large, flat fields from Texas to the Dakotas where 50-60-foot heads could easily be operated.
But the challenge with these larger head widths will be the uniform distribution of the residue and the unloading capabilities of the combine. Larger combines on the market today don’t have long-enough unloading augers to provide adequate clearance between grain carts and the wider headers. So as headers get wider this will need to be addressed. Some header manufacturers have decided to offset the header on the combine, which provides clearance between header and grain cart. But if the combine works up and down a field, it presents bigger challenges when it comes to spreading residue evenly.
It appears the three most successful principals to spread residue effectively comes from equipment that includes the following components of systems.
First would be a pair of larger diameter rotors. These would need to be mounted closer to the ground to help reduce the winds impact on residue distribution. They would ideally be either independently adjustable, or have adjustable shields to allow them to direct residue to one side or the other, according to slopes or side winds.
Another would be one that “blows” residue. Such equipment exists now, including the Redekop MAV straw chopper made in Canada. The Redekop MAV series of choppers create wind speeds between 100-150 mph depending on the specific model. This high volume of air helps blow residue and even out clumps of residue being ejected from the combine.
An effective residue management system would also need a pair of straw choppers, one mounted on either side of the combine. Such technologies have been utilized by New Holland in Europe for the past 10 years on its TR series. With this system, the residue stream is split into two directions with each chopper responsible for spreading each side.
The last component for uniform residue distribution could be a sensor that gauges wind speed and direction. This would allow the residue management system to automatically direct more material into a side wind or to increase the spread width when operating into a strong head wind. This could be best accomplished with a sensor on top of the combine that would relay signals to the residue management system, so it’s one less thing for the operator to worry about.