Explore the pros and cons of various cover crop varieties to know what to pick for your cotton field this winter.
Your cotton fields might benefit from several kinds of winter cover crops which can control erosion, manage nutrients, and improve soil health, including a crimson clover cover crop or even a vetch cover crop. But before you start purchasing seed or herbicide, it’s important to evaluate the benefits and challenges of some of the popular cover crop options.
Here’s what you need to know about the major types of cover crop including grasses (also known as cereals), legumes and brassicas.
Key cover crop species
Several cover crop species are common in winter cotton fields. Evaluate the pros and cons of each to determine which fits your specific situation – for example, whether you are planting FiberMax or Stoneville cotton varieties. FiberMax includes several early- to mid-maturing varieties, which can establish quick stands that provide relatively continuous canopy to keep the soil cool post-cover crop termination. Meanwhile, Stoneville offers several varieties that pair well with a dry or sandy soil, the same kind of soil in which crimson clover can thrive.
Cereal/grass cover crops benefits and challenges
Three primary cereal and grass cover crops can be a potential fit for cotton fields.
Cereal rye
This cover crop produces a lot of biomass, making it excellent for weed and erosion control. It’s also an effective nutrient scavenger. However, it can immobilize nitrogen in the spring, and due to high levels of biomass, it leaves heavy residue.
Wheat and barley
These covers provide good soil protection thanks to their deep root systems. They’re quick to establish and terminate. Yet compared to rye, wheat and barley generally leave less available nitrogen for your next crop.
Triticale and oats
Quick establishment and moderate biomass production are among the benefits of this cereal cover crop. Be aware that triticale and oat crop residue doesn’t stick around as long as that of rye or wheat, resulting in less weed suppression.
Legume cover crops benefits and challenges
Two legume cover crops for cotton include crimson clover and an Austrian winter peas cover crop – with some important caveats.
Crimson clover cover crop
This cover offers substantial nitrogen fixation. It’s relatively simple to manage thanks to a taproot that can be easily killed mechanically and its potential to reseed for future seasons. It also attracts pollinators. Your crimson clover cover crop can struggle to get established if conditions are cold or overly wet, so keep an eye out for disease, especially in and after a wet spring.
Hairy vetch and Austrian winter peas
You’ll enjoy high nitrogen fixation with these covers, though it’s important to recognize they have slow initial growth rates, so it will take time to reap full benefits. Vigilant management is needed because winter peas release chemicals that can prevent cottonseed from germinating and growing if cotton is planted right on the heels of cover crop termination.1 Volunteer plants can suck up nutrients and water that your cotton crop needs.
Brassica cover crops benefits and challenges
Another type of cover, the brassicas, can work well under certain conditions.
Turnips and mustard
These cover crops suppress soilborne diseases and provide rapid ground cover. Yet they produce less biomass compared to other cover crops. Unwanted volunteers cause management headaches.
Cover crop selection considerations
Adopt a strategic approach to determine what type of cover crop fits your needs best. It might be a crimson clover cover crop or Austrian winter peas. In other cases, a vetch cover crop might make the most sense. Consider your goals. Are you optimizing for row-crop yield, weed control, nutrient availability, all three – or something else entirely?
Evaluate field conditions and weather patterns. Study your crop-rotation plans, expected cover crop termination timing and available resources to decide which covers to use.
Practical cover crop management tips for cotton fields
For best results with legumes in cotton fields, plant covers into warm and moist soils before your cotton crop is harvested. Overseed winter legumes about two weeks before defoliation.2
Small grains can be planted after your cotton harvest for fall and winter erosion protection.
Plant cereal rye early to limit problems planting into excess biomass in the spring. Terminate it using roller crimping or a burndown herbicide about 10 days before planting to maximize weed suppression and soil moisture.
If you are planting a cover crop mixture required by many conservation programs, recognize there can be several benefits for cotton fields, including the potential of increased nitrogen availability.3 Consider a mix of cereal rye, which can limit erosion and hold onto nutrients, and hairy vetch, which can provide nitrogen to future crops.4
Cover crops should be terminated several weeks prior to planting cotton to allow the residue to breakdown for effective planting while offering some ground cover and weed suppression.
Experts are available to help you make your winter cover crop decisions for your cotton fields. Reach out to your seed retailer, a nearby extension office agent or a seed company professional like your regional BASF representative.
Source: https://www.agweb.com/