Dig into toolbox to manage residue
By CLYDE TIFFANY
With higher yield goals, higher plant populations and aggressive fertilization, you need to manage increased amounts of crop residue to establish productive stands the following year. This is especially important if you are planting corn following corn. Typically, soybeans can tolerate more residue than corn.
Uniform emergence is critical to optimizing yield potential in corn. The greater the delay in a plant’s emergence compared to neighboring plants, the more likely it will be a weed instead of a productive plant contributing to yield. Each day emergence is delayed, yield potential is further reduced. Also, residue insulates the soil from the sun, so soil temperature under the residue can lag behind temperatures under the bare soil by several degrees for an extended period of time in the spring. A 180- to 200-bushel corn crop can produce 10,000 pounds of residue per acre. High levels of residue slow seedling growth, particularly root development, even if soil temperatures only drop as little as 3 to 5 degrees. If root development is compromised, uptake of nutrients by the seedling is reduced. Delaying early growth and nutrient uptake affects yield.
Key Points
• Residue management is critical, especially when planting corn on corn.
• There are different tools you can use in different situations.
• Goal: Reduce residue levels enough that planter trash whippers will clear strips.
Uniform distribution
With larger planting and harvesting equipment, it’s more important to pay attention to chaff spreaders and chopping equipment. Uniform distribution may become difficult with larger row-crop harvesters. Residue needs to be:
• cut and sized so it can be broken down more rapidly
• spread uniformly across the swath of the combine
• chopped for better incorporation with tillage.
A traditional stalk chopper needs to be run carefully so residue is drawn up and chopped well. Be sure to adjust chopping headers so that they spread residue uniformly. Some headers have spread a heavier swath in one direction, causing excess residue to lie on certain rows. Those rows have seedlings delayed in development. The delay carries through the rest of the year and is noticeable with strips of plants tasseling and maturing at different times.
Vertical tillage equipment, employing narrowly spaced ripple coulters, has come on the market to better handle the sizing of residue prior to the deep primary tillage. These tillage tools require high horsepower to pull them at speeds of 9 to 10 mph for most effective sizing of stalks and root balls.
Livestock producers can reduce residue by baling excess corn residue for bedding.
Heavy soils in fairly flat fields where erosion has limited risk still may benefit from moldboard plowing to bury residue. Take soil tests before tillage so fertilizer can be incorporated with the primary tillage.
Good fall residue management allows producers to clear a 6- to 10-inch wide path in front of the planter row units with trash-whippers. The soil in these
residue-free strips warms up faster than the soil between the rows.
Tiffany is an area agronomist for Pioneer Hi-Bred in Spicer, Minn. He can be reached at clyde.tiffany@pioneer.com.
RESIDUE IMPACT: Proof of the impact of too much residue can be seen in seedling emergence (top) and seedling size (bottom). Plants growing in more residue are on the left.
This article published in the September, 2010 edition of DAKOTA FARMER.
All rights reserved. Copyright Farm Progress Cos. 2010.