As the market for organically grown products increases, producers are struggling to keep up with demand. While conventional farming relies on inorganic means to boost production and control pests, organic farming has more limited options. UF/IFAS researchers have begun a multi-year study on whether double-cropping can improve yields, improve soil health, and minimize environmental impacts. It is part of a larger USDA grant project the University of Tennessee (UT) is leading. The UF/IFAS researchers are Dr. Emma Matcham (Department of Agronomy), Dr. Gabriel Maltais-Landry (Department of Soil, Water, and Ecosystem Sciences), and Dr. Zane Grabau (Department of Entomology and Nematology).
Double-cropping (DC) is the practice of harvesting two row crops from the same land in one year. For example, growing wheat or barley from fall to spring and then soybeans over the summer. This successive growing season model has benefits, but also poses challenges. Overall, it is unclear what role double-cropping can play in promoting sustainable, organic agriculture.
“Currently, there’s not enough information on how profitable double cropping is for the organic farming sector in the Southeast,” explained Dr. Sindhu Jagadamma, associate professor of soil science at the University of Tennessee and project director. “This is especially true for grain and forage crops. These trials in Florida and Tennessee should give us a better understanding.”
Rewards and Risks
The two teams will compare the effect of different DC systems on grain and forage yield and nutrient uptake, the quality of the forage, and weed response. The teams also will look at the impact of different post-harvest residue and weed management methods on soil properties, including soil health and soil nematodes.
“This includes soil physical, chemical, and biological indicators,” explained Maltais-Landry, UF associate professor of nutrient management and soil health. “The goals are to see if intensification is sustainable for soils, if weeds are suppressed, and if nematode pests are controlled.”
The project also involves comparing the economics of the different DC systems against each other, and how they perform relative to single-cropping systems. One question is whether a DC system can cover the cost of additional inputs for two different crops in a single year. Another is whether harvesting two crops can offset the potentially lower yield of the second crop in the DC system. Researchers will assess the production, marketing, and financial risk management tools available to organic crop producers as well.
“There is also a risk of timing out the harvesting and planting of two successive crops,” Maltais-Landry added. “We can’t control the weather. If there is a delay in harvesting the winter crop, that shortens the soybean and corn growing season. That risk is especially important in Tennessee, where the winter growing season is less favorable than in Florida.”
Study Set-up
The 3-year field experiments are taking place on certified organic lands in Knoxville, TN, and Citra, FL. Slightly different crop rotation treatments will occur in each location, aligning with the differences in climate and soils, growing period, stakeholder preference, and marketing opportunities. Additionally, they will split each rotational treatment plot into two subplot treatments. The teams will test two different residue and weed management goals:
- Maximizing production by managing weeds with aggressive tillage, potentially at the expense of reduced soil health.
- Enhancing soil organic carbon accrual and soil health by reducing physical soil disturbance, potentially at the expense of weed control and yields.
Cover crops planted before corn also will vary to provide more nitrogen in one subplot and more carbon inputs in the other.
Researchers will measure soil population densities of plant-parasitic nematodes, before planting and just before harvest of each summer cash crop (soybean or corn) for selected treatments. “We’re only assessing nematodes at the Florida site,” noted Grabau, UF associate professor of nematology. “The reason is the sandier soil is more likely to produce plant-parasitic nematode damage, according to previous and ongoing research.”
Resources for Organic Farmers
After data analysis, the team will create comprehensive extension and education programming. They will author several peer-reviewed research articles based on their findings. Videos, website updates soliciting stakeholder engagement, and informational blog posts are part of the outreach effort.
“We need to share what we learned with organic farmers and extension agents,” said Matcham, UF assistant professor of agronomy. “This is necessary to achieve profitable and sustainable organic practices in the Southeast, a region where organic farming is more challenging than in other areas of the US.”
The “Tapping the Potential of Double-Cropping for Profitable Organic Grain and Forage Production in the Southeast US” research project is slated to run through August 2028. The federal grant that supports the work totals nearly $1 million.
This work is supported by the Organic Transitions Program, project award no. TEN2024-04000, from the U.S. Department of Agriculture’s National Institute of Food and Agriculture.
Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and should not be construed to represent any official USDA or U.S. Government determination or policy.
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