Residue Management

Tuesday, November 19, 2024

Setting The Stage For #Plant2025

By Paul Hermans

Are you thinking about planting next season? Hopefully, the answer is yes. The most important thing you can do to set the stage for a successful planting season next year is to control residue this fall, during and after harvest.

With increased yields in both corn and soybeans, more residue is left over, which provides a challenge for planting next year’s crops into that residue – especially if you are in a no-till/reduced tillage management system.

When I first started weighing off corn plots, corn averages hovered around 140 to 160 bushels per acre. Flash forward to 2023 and yields in similar plot geographies were topping 220 to 240 bushels per acre.

Improved genetics and paying better attention to agronomy management have resulted in bigger yield gains. Studies have suggested that genetic gains in corn yield account for 50 to 60 per cent of total corn yield gain on an annual basis, with sound agronomic management contributing to the other portion.

Using a simple factor of 0.5 pounds of residue for each bushel of corn produced gives us a snapshot of just how much extra residue is produced on an acre basis in the plot examples below.

A lot of this yield gain can also be attributed to higher plant stands. The hybrids of today can take stress (higher populations; closer inter-row competition) a lot better than hybrids of years gone past.

If we look at corn populations, we have gone from an average of about 26,000 to 28,000 plants per acre up to an average of 32,000 to 34,000 plants per acre over the last 25 years. That increase in population means more plant biomass is produced, which must be dealt with.

On a population basis, an extra 6,000 plants per acre would equate to 42 to 60 more bushels of corn yield, depending on the maturity area and length of the growing season. This assumes seven to 10 bushels per every thousand ears harvested. That means an extra 2,352 pounds to 3,360 pounds of grain and 1,176 pounds to 1,680 pounds more residue on an acre basis.

Other genetic changes are coming, such as reduced stature in corn. This new concept has shorter internodes than today’s hybrids.

Plant leaf architecture is the same; however, plant heights are reduced by one-third. This assists with less residue and allows growers to have more options to manage the crop with application equipment that can easily be driven over the top of shorter corn.

We also need to keep in mind the principle of carbon to nitrogen ratio. If carbon is more than 25:1, residue will be slow to break down and require nitrogen to help with microbiological activity. Below a 25:1 ratio, this will speed things up, with more nitrogen being made available to microbes to help with this process.

In the future, biological additives will assist with the biological breakdown of residue, which, in essence, acts like a recycling program in your field, returning valuable nutrients and carbon back into the soil for next year’s and subsequent years’ crops.

Do not get me wrong – extra residue is putting more nutrients back into the soil. The question is: How are we managing this residue, focusing on next year’s planting season?

Switching gears … let us think about residue and how it can affect a crop being seeded into it.

The first issue is plant ability – getting proper seed depth and seed-to-soil contact. Poor seed depth or seed-to-soil contact can reduce plant stands, as in the case of planting soybeans into heavy residue corn fields.

Residue can act like an old-fashioned oil lamp. If “wick” residue is caught in the seed trench, it wicks moisture away from the seed, affecting germination, especially in soybeans planted into corn. In high-residue corn fields, corn residue (some people refer to it as trash) acts like a spring, preventing the downforce of drills/planters, and impeding the pressure needed to achieve proper seed depth.

I always get asked which is better – chopping corn stalks with the combine header into fine residue and leaving it on the surface, or leaving it standing?

In principle, finer residue will break down faster. One issue is timing of harvest. Compared to our friends down south in the United States, we harvest later in most parts of Eastern Canada – which means cooler fall temperatures and less microbiological activity in the soil. This can also mean a mat left on the surface the following year, leading to cooler temperatures and slower dry-down at planting time. However, residues on the surface assist with soil management from an erosion standpoint, especially if you are in an area with highly erosion-prone topography/soil.

There are assorted options to manage this residue, such as strip tillage to move this residue and create a seven to eight-inch soil management zone, or the addition of row cleaners on planters.

For soybean growers who are planting wheat and chasing the combine out of the field with the planter, ensuring residue is evenly distributed is a priority. Setting the combine up right from the get-go is critical to achieving residue distribution across the entire header width.

This will aid in consistent uniform emergence of wheat.

When we think about residue, think about it as a house. The wheat seed needs to live in this as it starts its life cycle. Too much soybean residue in an area will mean cooler, wet conditions will persist if too much rain occurs after planting. Seeding depth can be dramatically changed with residue being caught in the seed trench. This can lead to differences in emergence timing and potentially lead to less tillering.

Fall harvest season is busy, and we are all anxious to get the crop in the bin. Taking some time to adjust combines properly and thinking about the next growing cycle will go a long way to setting ourselves up for the next big win.

Here is hoping harvest has gone smoothly on your farm operation. All the best. BF