Cotton prices are good, soybean prices suspect and a high percentage of the wheat planted in both North and South Carolina has become a cover crop. While cotton and wheat aren’t a popular combination in the upper Southeast, Mother Nature may have sparked some interest in the grain-fiber combination.
Record fall rains that generally started in mid-November across the region delayed harvest of grain crops, cotton and peanuts and pushed back or eliminated wheat planting. Late planted wheat, and to a lesser degree wheat planted in late September and October, was subsequently damaged by a series of cold fronts that dumped record amounts of snow and produced record cold weather across the region.
In March and April many growers in the upper Southeast were faced with the question of whether to take their wheat crop to maturity. Though a few did, and some claim damaged wheat has shown an amazing resilience this spring, most chose to spray it with glyphosate or gramoxone or mechanically cut it.
What to plant in the early burned down or cut down wheat has created some interesting options for growers. One of those is planting cotton into the wheat stubble.
The first challenge is to get even emergence of cotton plants planted into wheat stubble. The goal of planting should be good seed-soil contact with minimal seedbed disruption to preserve soil moisture. This combination can be challenging because of the wheat straw residue.
With cotton planting well under way, much of the cotton planted into wheat in the upper Southeast will be planted late in cotton planting season. Planting cotton very far into June has not traditionally been a good plan for growing good cotton in the upper Southeast.
Several options are available for planting cotton in this environment, including no-till and burning the wheat straw. Burning removes the residue, but likewise the benefits of this residue, such as increased organic matter, greater rainfall infiltration, moisture conservation and lower soil erosion potential, will be lost. Thus, planting cotton directly into the stubble without burning is a good option.
Research at Louisiana State University indicates when planting cotton no-till following wheat harvest, it is critical to ensure the straw chopper on the combine effectively distributes the straw as evenly as possible.
No till farmers frequently use residue managers or “trash wipers” on their planters, which can be highly beneficial and improve the consistency of the seeding operation. To avoid disturbing the seedbed, trash wipers should be used with the least amount of ground contact possible.
No-till coulters, which are usually fluted, disturb the seedbed more than is needed and interfere with seed placement. Most producers have opted to remove coulters when planting cotton into wheat stubble.
Because the wheat is cut or burned down prior to the plant heading out, much of the nutrients needed to produce seed will remain in the soil. How much nitrogen left in the soil is a particularly critical question?
In a typical wheat field taken to maturity, approximately 35 pounds of nitrogen remains per 5,000 pounds of stubble. Taking wheat out with herbicides or mechanically before it goes to produce heading should leave more residual nitrogen for cotton production. A good crop consultant, well versed in mid-season nitrogen analysis may be the best option for knowing exactly how much nitrogen is left for cotton — or any other subsequent crop.
Using partially mature wheat as a cover crop in the upper Southeast essentially leads to late-planted cotton. Growers are commonly faced with planting delays, and managing cotton on wheat stubble will be a similar management challenge.
Early or early-mid maturing Roundup Ready Flex varieties stacked with Bollgard II or Widestrike insect management traits are good options for managing the risk of increased insect pressure in late-planted cotton.
Warm, typically wet weather conditions in June, also puts late planted cotton at a higher risk to weed pressure. The ability to apply glyphosate over-the-top for weed control in a timely manner will help reduce this risk.
Also, late-season weed pressure, particularly from grasses, can be a problem, and the ability to manage these weeds throughout the season with glyphosate will likely be of great benefit.
The combination of late planting and planting cotton into wheat stubble calls for an increase in seeding rate. How much of an increase will vary from location to location, even variety to variety, but limited research across the Southeast indicates that a seeding rate increase of 20 percent or so is adequate.
Because of the late planting, cotton seedlings won’t be exposed to thrips during their peak season. However, warm, dry weather is still no picnic, says veteran North Carolina State Entomologist Jack Bachelor. “As many cotton producers know in our region, the upper Southeast could well be designated the Thrips Capitol of the Cotton Belt,” Bachelor says.
Though traditionally a more severe problem on early planted cotton, the North Carolina State specialist says, “Extended hot, dry weather is no picnic either in dealing with thrips. In a series of 80 or so replicated tests conducted here and in Virginia during the past decade, untreated cotton lost an average of approximately 250 pounds of lint compared to the best at-planting treatments. That’s a lot of cotton lost to such a tiny insect,” he adds.
Treatment options for thrips are fairly limited. In North Carolina, Bachelor says for starters producers should plan on using either the 5 pound rate of Temik 15G, or one of the seed treatments (Cruiser, Gaucho Grande, Avicta, or Aeris). In most cases, plan on a foliar application for thrips following a seed treatment, Bachelor says.
Cutworms also can be a problem on late planted cotton.
Late planted cotton also will require some slightly different plant growth management strategy. Research at LSU indicates the best treatment is to target the early bloom window of application for initial mepiquat treatments to manage plant size and promote earliness. Popular match-head square application of plant growth regulators is not a good fit for late planted cotton.
Managing weeds in cotton is always a chore, but late planted cotton may create some slightly different challenges. Cotton planted in wheat straw is often slower to reach full canopy and the overall activity of soil residue herbicides, such as metolachlor, may be reduced because of the presence of wheat straw. This type planting system will not produce a good environment for reducing herbicide rates.
Mother Nature and agricultural commodity prices have combined to provide a rare opportunity for a wheat-cotton combo in the upper Southeast. However, growers need to be keenly aware of the fickle nature of both.
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