It’s important that a combine be adjusted properly to spread the straw across the full width of the header. With today’s widths in excess of 30 feet this can be a real challenge. Here are a few tips to help you do a good job (photos from left to right):
1. Residue sizing:Chopping the straw into smaller pieces will help with distribution and straw decomposition. Take cereals, for example. If you leave pieces of straw roughly eight inches long with two nodes intact, water and microbes will not be able to enter the stems from both ends to help with breakdown. If you don’t have a fine-cut chopper there are some very good aftermarket choppers available for most makes and models. Some aftermarket choppers will also help with distribution by incorporating fans on the ends that generate more air movement and wider spreads. Do a good job of chopping and distributing the straw and you won‘t need to use heavy harrow in the fall.
2. Chaff spreaders:Some new-model combines send the chaff through the straw chopper to help with distribution. The problem comes when you want to drop the straw for baling or burning. Most of the chaff will fall through the windrow and stay on the ground which can again cause uneven soil temperatures come springtime. I have seen instances on our farm where wheat was under-seeded with ryegrass and the ryegrass in the windrows was very uneven and slow to start the following spring.
3. Chopper knives:Chopper knives are often overlooked as regular maintenance items. Depending on the residue the knives may or may not be doing a good job of chopping and sizing. The sharper the knives the easier they cut and the less power they require to do a good job.
4. Windy conditions:On windy days it can be very difficult to spread the straw evenly across the width of the header especially when dealing with lighter residues. Some tailboards are adjustable from the cab to better manage variable winds and changes in harvesting directions. If you are harvesting in these conditions it is generally better to be moving across the wind on the downwind side than to try moving with and against the wind.