Monday, January 31, 2011
Ensure Your Second Year Corn Performs As You Expect
Crop budgets, market prices, and increasing yield potential are pointing to more corn acres this year than soybeans. And more corn will mean that quite a few acres will be planted in fields that also had corn in them last year. Whether you call that continuous corn or corn following corn, there will be some risks that you need to address. Let’s take a look at them.
Continuous corn is not recommended by many agronomists, but it still seems to happen. University tests will show a yield drag, but many farmers will deny that yields are hurt in second year corn. Since operators are going to do what they want to do, regardless the recommendations by researchers, the Ohio State University corn brain trust of Peter Thomison, Pierce Paul, Ron Hammond and Robert Mullen have provided their best suggestions for productivity, despite their recommendations being ignored.
1. Help your yield potential by planting corn in your fields with the best soils. Tests in many Cornbelt locations show that if there is any drought, corn that is rotated with soybeans will have a better yield performance than continuous corn. MN researchers found a yield differential greater than 25% for rotated corn over continuous corn where the environment hampered the yield.
2. Use Bt hybrids that resist corn rootworm if you have rootworm problems. They will be more pronounced in continuous corn, so helping your corn fight rootworm problems with Bt genetics in your primary fields and with soil insecticides in your refuge fields will work to ensure greater yields. If Optimum AcreMax RW is used, your refuge is “in the bag” and no additional refuge is needed.
3. Increase your nitrogen rates on your continuous corn. You are not getting the benefit of the nitrogen produced by rotated soybeans, so a higher rate of N would be required. The researchers say the additional N requirement will be 30 to 50 pounds per acre.
4. Plant hybrids that have demonstrated good performance in a variety of soil and weather conditions, since you want to reduce stress on your crop or plant a crop that is resists stress. Those environmental stressors could be drought, stalk strength, and emergence in poor soil conditions. Once you have identified hybrids that perform well under those conditions, plant hybrids that also have resistance to gray leaf spot, northern corn leaf blight, stalk rots, and ear rots that have been seen the past couple years. The researchers say fungicides have become popular add-ons, but they are not economical on corn that is already resistant to diseases and environmental factors. If you plant susceptible hybrids, then a payback from the use of foliar fungicides can be realized.
5. Since you will have increased crop residue to address, begin working on some strategies to deal with it. That may include stalk choppers and spreading residue evenly. No-till may not be the best practice for continuous corn. A no-till system is more likely to succeed on poorly drained soils with rotated corn. The researchers recommend strip till, use of row cleaners, and avoid planting on top of old rows. And they say the residue issue requires corn with good seedling vigor, good emergence, and good disease resistance.
While there have been many reports of equal yields of continuous and rotated corn, University of Illinois agronomist Emerson Nafziger said 2010 was a year that did not prove that to be the case. He said one thing that diminished yield in continuous corn was allelopathy, which means the prior corn crop created soil chemicals that were detrimental to the following crop. Additionally, the excess residue prevented soils from warming as rapidly and the need for early seed growth was retarded for the second year corn.
Summary:
Researchers are not recommending continuous or second year corn, but realize current economics will push many Cornbelt operators to plant corn back on 2010 corn ground. However, certain factors have to be considered that will affect the performance of the corn. There will be a need for the corn to be planted on the best soils to avoid diminishing the yield, the hybrid should be resistant to environmental and disease stresses, and Bt hybrids should be used where corn rootworms present a threat.
Posted by Stu Ellis on 01/31 at 12:54 AM | Permalink