Continuous corn will likely see a slight reduction in yields compared to corn rotated with soybeans or cotton — but with overall production capabilities still high, some growers remain sold on a corn-after-corn program.
It will likely require more nitrogen applications and potentially face more pressure from grassy weeds. But the added management practices can be worth it if 200-bushel or more yields can be placed in the bin.
Dale Seiler, who farms near Bradley, Ark., has been primarily a corn-soybean grower after halting his cotton program in 2007. About half of his crops are irrigated. “We are probably 50 percent polypipe and 50 percent center pivot,” he says.
For 2013, Seiler was 95 percent corn, with about 70 percent of that continuous corn that averaged 200 to 205 bushels per acre.
“My best corn is corn after soybeans, with yields of 215 to 220 bushels on average,” he says. “But for 2013, I wanted to go with mostly corn to take advantage of good prices. I do 30 percent to 50 percent of my marketing before harvest, when prices are normally higher. I also wanted to ease my harvest pressure.”
Seiler markets his corn through regional poultry operations — a steady opportunity to deliver when needed from his on-farm storage. That’s similar to other southern growers who have gone with more corn in their crop rotations in recent years.
Many farmers like corn-on-corn and look for better ways to hold down costs and obtain higher yields. He regularly takes soil samples, then uses variable-rate application to assure that fertilizer rates are accurate for each part of a field.
At corn-on-corn clinics conducted by Monsanto, Ray Ward, president and founder of Ward Laboratories, Kearney, Nebr., indicated that highest crop yields are associated with high soil tests for phosphate, potash, and zinc, along with properly managed rates of nitrogen and sulfur.
“Nitrate is soluble,” Ward says. “We only want to apply the amount of N that is needed for the current crop.
Corn-on-corn production forces farmers to focus on several agronomic factors. Soil fertility, residue management, seedbed preparation, weed control, disease pressure and insect pressure can require more effort.
“Because every field is unique, we encourage growers to carefully evaluate the emergence scores, disease tolerance and insect protection component of each corn hybrid when making selections for corn-on-corn acres,” says Ty Vaughn, Monsanto product management head.
Stacked corn hybrids, incorporating Bt proteins for insect protection and traits to provide herbicide tolerance, are a must to help prevent stresses the southern climate can place on corn-on-corn production and other crop programs.
Agronomists and entomologists say hard-to-control weeds and insects often require a combination of practices to help manage them, and scouting for insects is an essential component.
Scouting when peak corn rootworm flight activity occurs during the key months of July and August is recommended. By counting the number of adult corn rootworm beetles, a farmer can estimate the extent of corn rootworm larval damage he might expect the next year.
Continuous corn puts more pressure on farmers for early planting than if soybeans are in the rotation. But getting seed in the ground at the right time can certainly boost yields.
The best corn planting dates vary from region to region across the Mid-South and Southeast. For example, in South Carolina, the most active planting period is between March 20 and April 20. Planting usually begins in early March, according to Clemson University Extension.
Spreading planting dates and maturity groups can help with planting and harvesting operations. If conditions allow, corn needs to be planted at the optimum time. If many acres need to be planted, start planting when conditions allow it in order to finish within the optimum planting time.
Higher grain yields are usually obtained when corn is planted as early as weather conditions permit. Higher yields from early-planted corn are mainly due to reduced pest pressure late in the season, better rainfall patterns and cooler air temperatures during silking, Clemson says.
Other advantages of early-planted corn include higher soil moisture at planting, lower temperatures during pollination, earlier maturity, earlier harvest in the fall and higher yield and test weight potential. Clemson says early planting dates also result in faster canopy closure in the growing season, better stalk quality and may help reduce late insect and disease pressure.
When planting, start with full-season hybrids first, then plant early-season and mid-season hybrids, Clemson says, noting that full-maturity hybrids have the benefit of maximum heat unit accumulation.
Use short- or medium-season hybrids when planting late. Delaying planting of full-season hybrids would reduce yields more than short- and mid-season hybrids.
However, planting corn late in the growing season increases insect and disease pressure and the risk of low yields due to pollination occurring during a period of high temperature and moisture stress.
Seiler says he will likely revert to more of a 50/50 corn-soybean rotation for 2014 to take advantage of agronomic benefits available from that type of program.
Rotating corn with cotton, soybeans, peanuts, tobacco and other crops can help reduce weed, insect, and disease pressure and improve yields. Additionally, rotating crops helps to remove phytotoxic substances produced by corn and improve soil physical properties, Clemson says.