ARS Scientist Highlights Till vs. No-Till Farming
To till or not to till? That is the question.
Looking over fields prior to planting, a Shakespeare-in-overalls might also wonder: "Whether 'tis nobler to till and suffer the slings and arrows of soil erosion, decreased irrigation efficiency, and greater operational expense or take arms against such troubles by not tilling and run the risk of increasing pest cycles."
Farmers every year must decide whether to till their fields in the conventional manner or join the growing number of farmers who are going back to the roots of agriculture by preparing the soil using no-till methods. There are benefits — and drawbacks — to both systems. As the great poet once coined, "all that glitters is not gold."
According to Steven Mirsky, research ecologist with Agricultural Research Service's (ARS) Sustainable Agricultural Systems Laboratory in Beltsville, MD, there are economic and environmental considerations for farmers to keep in mind when making their decision.
Both methods "work" the soil, which gives the seeds a place to go and easier pathways for root systems, but each method effects the farmer differently. "Tillage turns the soil, while no-till uses disks to slice into the ground and slip seeds in the narrow slice," Mirsky said. "There is no soil disturbance of substance in no-till."
In terms of labor, tillage-based systems require several field operations to prepare a seedbed. The soil must be worked and then packed to facilitate the best conditions for putting crop seed in the ground. No-till production requires heavy-duty planters that can cut the soil and put seed at a precise depth in the soil profile as well as close the slit the seed was deposited into.
While tillage loosens up the soil, incorporates all surface residues, and leaves the surface clean, which helps improve the planting of cash crops, it also leaves the soil vulnerable to erosion, Mirsky said. On the other hand, no-till systems are excellent at reducing erosion, but do not break up pest cycles like tillage does.
In conventional tillage (left), a winter rye cover crop has been mixed with the soil, while in strip tillage (right), the rye residue is left on the soil surface. (Photo by David Bosch, D3495-1)
"No-till farming greatly reduces soil erosion," Mirsky said. "Intact soils also maintain root channels that facilitate greater water infiltration and storage. No-till tends to increase soil organic matter in the top several inches of the soil. On the other hand, tillage can act to bury carbon and increase its storage. That said, overall, intensive tillage tends to burn up much of the soil organic matter, more so than no-till."
According to Mirsky, these operational matters impact the farmer economically, too. No-till tends to require much less fuel and labor expense because it does not require all the energy needed to push farm equipment through the soil. No-till typically requires less field operations and equipment.
Over time, however, no-till systems can develop herbicide resistance if other integrated weed management strategies are not used, thereby increasing pest management requirements.
Mirsky said there is another variable that could benefit no-till systems — cover cropping during the offseason.
"Cover crops play an important role in helping to ensure the long-term viability of no-till farming," he said. "Cover crops help dry out the soils in the spring to ensure earlier access for field operations and help conserve soil water in the summer during periods of drought, suppress weeds, and slow down the evolution of herbicide resistance."
If a farmer wants to try a no-till approach with cover cropping, harvest season is the best time to begin the process. Then the farmer may realize that parting with the till approach is not such sweet sorrow. – By Scott Elliott, ARS Office of Communications
