What is in this article?:
• Research has shown that a comprehensive rotation program, coupled with reduced or no-till systems, provides far-reaching benefits.
• Perennial grasses push roots deep into the soil and build organic matter.
• Cattle play an important role in the sod-based system.
JIM MAROIS, University of Florida.
“It also increases economic diversity by adding cattle, hay and grazing options. The system also reduces the amount of time producers spend on certain (seasonal) activities.”
He explained that rotations that include perennial grasses spread risks by dividing center pivots into quarter circles. “With just 50 acres of cotton, for instance, producers face less stress to plant in a limited time. They also have greater flexibility and can respond to commodity market changes.”
He’s worked with a no-till, sod-based system that included: cotton, bahiagrass, bahiagrass and peanuts. A conventional-till rotation system included: peanuts, cotton, cotton and peanuts. “We used a winter oat cover crop in both systems.
(For an in-depth look at a sod-based rotation improves cotton yields, visit http://southeastfarmpress.com/cotton/sod-based-rotation-improves-cotton-yields).
“One acre of bahiagrass,” he said, “produces 20,000 pounds of root mass in the soil, mostly in the second year. Oats produce from 3,000 to 4,000 pounds of organic matter. Sod-based rotation also sequesters an amount of carbon equal to 100,000 gallons of gasoline burned.”
He said the organic matter and soil moisture relationship is linear. “The more organic matter the more water in the soil.”
Leaching can be a problem in sandy Southeastern soil and is a particular concern near Florida’s many springs, Marois said. Sod-based rotations near those springs help protect the pristine waters.
He said no-till production “preserves what we have. Sod-based rotation restores what’s been lost — organic matter — by rotating perennial grasses through cropland.”
Cattle play an important role in the sod-based system. “We’re looking at the effect of cattle on compaction and nutrient extraction,” Marois said. Researchers are weighing such factors as: nitrogen uptake, earthworm populations, soil compaction, crop yield and quality, organic matter content, economics, the impact of cattle on the soil, soil respiration and other issues.
“We’re also looking at the possibility of reducing nitrogen demand significantly with this system.”
He said cotton typically requires 50 pounds of nitrogen to make one bale of cotton. “We’re looking at growing three to four bales of cotton with just 60 pounds of nitrogen.”
A bahia, bahia, peanut and cotton rotation could be a key. “Bahia roots punch through the compaction layer and earthworms then push through. Cotton roots follow and go deeper (than usual).”
He said water infiltration increases significantly with a bahiagrass rotation. “Hard rains soak in quickly,” he said.
Deeper roots make a significant difference in avoiding water stress. Marois said roots that penetrate to six inches will need water every three days. Roots that probe to 60 inches can go without water for 30 days without moisture stress.”