Most U.S. no-tillers miss out on the full benefits of no-tilling because they incorrectly believe they must occasionally till for a variety of reasons, says Rolph Derpsch, an internationally respected no-till researcher and advocate from Paraguay.
For example, he says, no-tillers in South America disagree with the idea of incorporating lime with tillage implements after no-tillage has been started. Rather, South American no-tillers believe the surface application of lime in combination with specific cover crops allows the movement of lime through the soil profile.
The subject is still a matter of debate in the United States, he notes.
Also, he points out, many researchers, extension agents and no-tillers in the United States believe in occasional tilling to redistribute phosphorus that concentrates on the soil surface after a few years in the no-till system.
“This is not the case in South America, where no-tillers have learned that the concentration of this element in the soil surface is not a problem at all for obtaining high-yield crops,” he says.
“The contrary is the case. When tilling the soil to redistribute phosphorus, this element has greater contact with soil particles and many soils then bind phosphorus very strongly, not releasing it for plant use.”
Derpsch also points out that U.S. and South American no-tillers disagree about the remedy for soil compaction in long-term no-till fields.
“South American farmers have learned that a permanent soil cover, the use of strongly rooted cover crops and diverse rotations allow soil biology to develop and…