As we have increased the plant population in our fields and increased our yield with hybrids that are larger and more productive, we have increased the total biomass in our fields and increased the residue that we must manage at harvest. While so much of our efforts in harvest focus on getting the grain out, managing what is left over is also of the utmost importance to our success next season and next.
Residue affects the warming and cooling of our soil, as well as water infiltration and evaporation and nutrient penetration and release. Residue is a factor in disease pressure as well as some unfortunate afflictions, such as Goss’ Wilt, harbor in residue between seasons. The proper management of your residue not only tips the scales in your favor regarding efficient water usage, soil temperature, nutrient conservation, and disease resistance, but also eases your ability to work through problems in future seasons.Well-managed residue can be identified on just one main point: how evenly it is distrusted.
Evenly distributed residue ensures that the soil you plant in come spring warms and cool evenly, accepts and releases water evenly, and has an even distribution of minerals and nutrients. The consistency of these things throughout your fields will dictate the consistency of your plants. Evenly distributed residue also makes for smooth fields, which is a highly desirable feature as the smoothness of your fields also plays a major role in the consistency of your crops. Smooth, consistent fields will yield smooth and consistent crops.
As combines have gotten larger though, even distribution of residue has become more of a challenge as the residue must be thrown the equivalent width. Letting your cornhead do much of the work will help with distribution: use the cornhead to process 90% of the residue to decrease the amount of plant material going into the combine and decrease the amount of work the combine must do (because it has quite enough to do already). Using your cornhead is preferable to making a second pass with a stalk chopper as they tend to produce too fine a residue and can create or exacerbate compaction problems. With beans, even distribution of residue depends on your combine being able to throw residue as wide as your bean head. Evenly when these two are properly matched, make certain that your chopper is running right and be sure to adjust for windy conditions during harvest.
Leaving 10-12 inches of plant in the ground provides important protection for the residue that has been processed and spread. Leaving enough plant to protect this residue from rain, wind, and snow will minimize drifting of processed residue, which is highly desirable as drifting affects both distribution and the smoothness of your fields.
If your combine spreads residue inadequately or if your fields suffer residue drift over the winter, you will soon notice a wavy aspect in your fields which will create problems for you whether you till or not. For you tillers, wavy fields are tough on discs, and discs will not correct the problem. Your issues will continue into the spring when you plant—here’s where the problem starts for you no-tillers as well—as your planter will ride the uneven residue depth and continue the wave into another season. As the wave feature always indicates uneven distribution of nutrients, water, and temperature, you can only expect uneven emergence from wavy fields.
For strip tilling, the end game is absolutely the same as it is for conventional tillers and no-tillers: planting into a consistent seed bed in the spring. Ensure that your machine is set properly to place residue in strips 6-10 inches wide and outside the seed bed.
Since I can’t very well make a plug for my favorite topic—irrigation—as we talk about harvest, bear with me for a moment while I make a plug for my second favorite topic: cover crops. In terms of residue management, cover crops have much to offer: they will facilitate microbial action which will attach residue to the soil, reducing the risk of drifting, and will get nutrients back into the soil quicker so that they are readily available come next season.
Overall, sending a field into winter with well-managed residue is sending a field into winter ready for success in the spring. While you’re working so hard on getting the grain out this fall, remember to keep a careful eye toward what you’re leaving behind, since this is what you’ll be returning to with a planter in just a few short months.