Search continues for perfect cover crop

The search for the perfect cover crop continues. In one study being conducted over two years in multiple locations in North Carolina, triticale is looking like it might have the right stuff to provide cover and biomass.

Triticale is not a new crop, but it’s use as a cover crop is new enough to generate enthusiasm.

Mike Carroll, North Carolina State Extension agent in Craven County, is conducting trials as part of his Master’s thesis work at North Carolina State University. He’s comparing wheat, triticale and rye cover crops planted later in the year at different seeding rates. He’s examining which small grain cover will provide desirable results and act as a rotation crop in continuous cotton production.

“We’re looking at triticale as a cover crop, one that can be planted late, still get a lot of biomass produced, and boot or head prior to termination, has deep root penetration and is easy to terminate with relatively inexpensive or low rates of herbicides,” Carroll says. “If you can get all of that, you have the ideal cover crop in a continuous cotton system.”

“Very seldom with cotton do we get a rotation or any significant crop residue accumulation in eastern North Carolina,” Carroll says. “That’s why we are talking about cover crops.”

On the farm of Craven County, N.C., farmer Donald Heath, a former Farm Press High Cotton award winner, Carroll showed his research to a group.

“A lot of folks want to go with wheat, but you don’t get the biomass with wheat,” Carroll says. “Triticale seems to be more consistent across soil types and tolerates greater weather variables than wheat but still provides the biomass we often associate with rye.”

On Heath’s farm that consideration is an important one. “We have the luxury of 20 soil types in one field,” Heath joked with the group. “When you see what happens with variable soil types, you begin to understand the importance of a cover crop.”

To illustrate the differences within one field, Heath said the triticale was planted at a depth of two inches on one end of the row and almost on top of the ground at the other end.

The benefit of a thick cover crop is the biomass or organic matter that it creates. Heath says a thick cover crop is equivalent to an irrigated crop.

In his research, Carroll is looking at triticale at various seeding rates targeting populations of seven, 14 and 21 plants per foot of row. Additionally, another variable, additional nitrogen of 20 pounds per acre is added to evaluate whether the additional nitrogen will improve biomass production or cotton yields.

Carroll believes a cover crop such as triticale will impact the soil’s water-holding capacity and long-term physical structure. He’s asking the questions, “Can we plant cover crops late and can we compensate cover growth from late planting by using a greater seeding rate or additional nitrogen?”

Underscoring the importance of a cover crop is preventing nitrogen loss.

Farmers in the Neuse River Basin have to manage nitrogen losses under new rules developed to decrease runoff by 30 percent.

The goal is to see which regime gets the best results the fastest, without losing nitrogen. “In theory, you harvest and plant a cover crop by the end of September,” Carroll says. “In reality, in cotton, harvest may not be until mid-November and you still may have lost nitrogen.”

Bill Smith of Resource Seeds is providing Carroll with new varieties in the company’s Trical line. “We’re trying to come up with better lines that have more biomass and have a beneficial effect on cotton.

“The ideal is to have triticale that is short and is booting or heading when the farmer burndowns the cover,” Smith says, “but one that can be planted by Nov. 15.”

Smith says “cover crops need to be pushed a lot more than they’re pushed because there’s no perfect season in the Southeast.”

Carroll says triticale is a good option, but believes his research will show that rye will produce more biomass. “Part of the problem is that we have limited data on triticale.” In the past, triticale varieties have been incredibly variable. Winter-hardy varieties bred in other parts of the country don’t do well in eastern North Carolina.

He says Resource Seeds has done a great job breeding to compensate for this factor and has released varieties according to regional research. “This research will likely show that Trical 498 will produce equal to or very similar to rye,” Carroll says.

For farmers, Carroll recommends staying with proven varieties for the eastern North Carolina area, such as the Trical varieties or Arcia, the North Carolina State University release.

In his study, Carroll is using multiple sites and taking biomass samples, in addition to watching how the crop degrades over the season. Cotton yields and tissue samples will also be taken.

Bobby Brock of the USDA Natural Resources and Conservation Service in North Carolina believes that the research is essential in figuring out “what cover crops can do for us. In a sense, we really don’t know what the questions are.”

Brock, however, has noticed “a visible difference in the roots of cotton based on the seeding rate of triticale used as a cover crop. Carroll is looking at seeding rates of approximately 50-, 70- and 90-pounds per acre.

Under the Conservation Security Program, farmers are provided with cost-share programs to “make measurable differences in the soil quality and organic matter,” Brock says.

“Traditionally we have done a disservice in not making cost-share available to farmers,” Brock says. “This type of research needs to be funded. As conservation programs continue to evolve, cover crops will continue to be of greater importance.”

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