With much focus today on planting technology, tillage ideology and all types of precision technologies, attention to purposeful, precise primary tillage has fallen by the wayside. Fall tillage passes, including vertical tillage, chisel plow, disk ripper and moldboard plow, are done out of routine, tradition or necessity for a variety of reasons. But before you pull out a tillage tool for fall work, there are some things you should consider, says Jeremy Hughes, product manager for Horsch Equipment Co.
First, ask yourself what you need or want to accomplish with fall tillage. Is it simply to rip up the field? Are you looking at “getting it black”? Or just looking to scratch it up? A fall tillage program is also the start to seedbed preparation, something many farmers forget. The quality of tillage, finish and residue management done in the fall will have direct impact on the quality of the seedbed in spring. Thinking forward, there are several details to consider when approaching fall primary tillage as a step toward seedbed preparation.
• The combine. First thing to keep in mind with fall tillage and seedbed preparation is that the process starts with the combine during harvest. Whether you are using no-till, minimum till, conservation tillage or conventional tillage practices, paying attention to the details of crop residue management with your combine is the ultimate first step.
Maintaining sharp knives and stationaries on a wide-spreading straw chopper works wonders when it comes to sizing residue at harvest. Chopping corn heads offer a leap forward to residue decomposition and offers proven yield benefits, year over year. A uniform and consistent layer of finely chopped residue will ensure the beginning of a proper seedbed, whether you no-till or are preparing for fall tillage.
• Residue sizing. The importance of accelerated decomposition of crop residue can give soils and crops many benefits, but it can also create some issues if not managed properly. One thing to consider with choosing fall tillage techniques is what will work best on your farm to not only maximize residue benefits, but also minimize the negative effects, such as erosion and runoff.
Residue sizing starts with the combine and must be done with each tillage pass until planting. With today’s GMO and hybrid crop technologies, you have strong stalks to hold plants upright throughout the season. The downside is that these stalks, once the crop is harvested, take longer to decompose than conventional crops. Also, accelerating residue decomposition is essential. The only way to accelerate decomposition is to ensure additional sizing with every pass.
For example, each time you cut a cornstalk in half, you double the amount of “doors” that digesting bacteria and fungi can enter. This process starts with the combine, with chopping corn heads and with wide-spread, fine-cut straw choppers. As you start your fall tillage program, ensure additional residue sizing beyond what is done with the combine.
Along with residue sizing, incorporating the residue with soil is crucial for accelerating decomposition. Residue must be introduced to soil bacteria and fungi in order to break down, and the only way to do that is through maximum soil-to-residue contact.
• Residue security. Have you traveled down the road and seen ditches full of cornstalks? Wind and water can loosen unsecured residue very quickly. Especially when considering a shallow fall tillage pass, ensure you are not only sizing residue but also securing it in the field. Getting residue sized, mixed with soil and firmed down will keep the stalks out of the ditch and accelerate the decomposition process.
Fertilizer nutrient value (FNV) is a term used to quantify the nitrogen-phosphorus-potassium, micronutrient and organic matter contents found in postharvested residue. When crop residues are properly managed, you can unlock and use the FNV that remains in the residue, which is basically like leftover fertilizer.
For example, in many studies, 200-bushel corn will typically leave behind 4 tons of residue per acre in the field. For each ton, there are approximately 20 pounds of actual N, 7 pounds of actual P and 33 of actual K left remaining in the residue. That’s not even including micronutrients and organic matter values. Take the current dollar value of N-P-K per actual unit, multiplied by the amounts per ton of residue, and you’ll find $80 to $90 of fertilizer lying in the field. Your choice is to use it or let it go.
Residue also harbors many pathogens over winter that can linger into future crops. In recent years we’ve seen outbreaks of diseases such as diplodia, leaf streak and others due to spores harboring in residue that isn’t decomposed. The importance of securing residue and promoting accelerated decomposition not only adds nutritional benefits, but also aids in crop health management.
• Soil integrity. From planting through harvest, fields are constantly compacted. Machinery today gets larger and heavier. Big combines, grain carts, sprayers, tractors and spreaders roll across our soils so that by harvesttime, soil structure isn’t uniform or consistent. Managing soil compaction is one key goal of fall primary tillage.
When going down to break up compaction, keep this in mind. Rippers don’t always ensure uninhibited root growth by the following crop. Using technology for a thorough horizontal fracture helps ensure a consistent soil structure that will promote deep root growth and provide adequate water infiltration — yet leave a soil structure ideal for spring seedbed preparation. Providing some type of soil firming after fall primary tillage will help keep soils secure to help prevent erosion.
• What’s best for your farm and your soils. Every farmer has different conditions that require different practices to achieve a sustainable economic and agronomic outcome. Differences in soil type, crop residue levels, weather, climate and topography can all occur from region to region and farm to farm.
In some areas a thorough, shallow tillage pass is sufficient to prepare the soil and manage residue for next year’s planting. When considering a shallow tillage pass, ensure you are securing residue and promoting rapid decomposition, while maintaining soil integrity.
In other areas, deeper tillage is needed along with these dynamics to break up compacted soils. Some areas are left with minimal disturbance, and then tillage decisions are made in the spring. It depends on each farmer’s unique situation and cropping dynamics. As cropping conditions change, so does the approach to tillage. A one-size-fits-all approach isn’t always the best solution. For more information, visit horsch.com.
Source: Horsch Equipment Co.