No-till/high residue practices in dryland grain, pulse, and oilseed commodity production are now common across the Canadian Prairie provinces and are increasingly being used on the U.S. High Plains from Montana to the Texas Panhandle. No-till/high residue practices have largely replaced tillage and chem-based fallow on farm operations where they are utilized. Typically, off-season cover crops are not possible to use in these locales because of limited soil moisture and/or short growing seasons. Therefore, cash crop residue serves as the primary means of soil protection until the following growing season.
It is in the best interest of growers to maximize post-harvest residue to ensure maximum soil moisture retention, enable winter snow catch, and minimize soil erosion. One added benefit to maximizing post-harvest residue is that combine fuel consumption and overall wear and tear can be significantly reduced. Residue management behind the combine also becomes less of an issue since most crop residue is left standing. During the past decade, improvements in no-till drill and row crop planter design have made it possible to direct seed into significant amounts of standing residue while maintaining consistent seeding depth and minimizing hairpinning.
No-till/high residue practices also require maximizing residue at harvest. The most common approach to this is the use of stripper headers for small grains, canola, peas, and even shorter varieties of millet and sorghum. Stripper headers pluck cash crop heads and pods from the stalk. This results in significant amounts of standing residue post-harvest. Research from Western Kansas has shown that stubble left behind a stripper header must be 18 inches or higher in order to maximize soil moisture retention.
At this time, stripper headers are only available from one UK-based manufacturer, Shelbourne-Reynolds. The lack of competition in the stripper header market has resulted in high prices for both new and used units. AGCO/Massey Ferguson manufactured stripper headers primarily for U.S. rice growers between 1996 and 2006. While these AGCO units provide good performance and are easy to maintain and repair, they are increasingly difficult to locate on the used equipment market and their maximum width is a now narrow 24′.
Pan headers are made specifically for sunflowers seeded with a drill. They are designed to pluck sunflower heads from the stalk, leaving the stalk and root intact. Pan headers have long been on the market and are available from a variety of North American and European equipment manufacturers, resulting in more reasonable prices for new and used units compared to stripper headers. There are also a variety of all-crop heads that can be used for sunflowers planted using a row crop planter, but it is not clear if these provide the same manner of residue preservation during harvest.
There is little information on maximizing corn stalk residue in dryland corn in peer-review research, extension materials, or from equipment manufacturers. This could be because most corn growers east of the 100th meridian seek to break down corn residue as quickly as possible to facilitate cash crop planting/seeding the following spring. Some experienced dryland corn producers in Nebraska, Colorado, and Kansas have provided some points on how to maximize corn stalk residue for the following growing season, including:
1) Plant dryland corn in June and harvest late
2) Use less aggressive rollers and run the header at a height just under corn ears
3) Use a header with worn out rollers
Aftermarket conversion kits are available for converting standard corn headers to effectively harvest millet or sorghum while leaving most of the cash crop stalk intact. While these conversions are reversible, the amount of time and effort it takes to install them means that the header cannot be practically converted back to standard configuration quickly.