Most no-tillers won’t want to hear it, but some University of Nebraska research indicates an occasional limited tillage pass won’t seriously damage no-till’s favorable soil structure. But with herbicide costs increasing significantly this year, we’ve heard that a few no-tillers are thinking of using a light tillage pass as a weed control option.

Don’t Get Me Wrong

I’m not advocating that no-tillers use any tillage. But maybe the consequences of making a single tillage trip across a no-till field isn’t the disaster you might have imagined. 

Charles Wortmann, a Nebraska soil and nutrient management specialist, says occasional tillage in a no-tilled field needs to deal with a specific objective. This could include controlling weeds, fracturing a soil compaction layer, incorporating lime or manure, reducing the vertical stratification of nutrient availability, eliminating ruts, increasing soil organic matter to a greater depth and dealing with heavy crop residue accumulation. 

Even so, he doesn’t recommend occasional tillage more than once every 5-10 years. This is based on several 5-year studies that compared five occasional tillage practices under no-till conditions.

An early concern among the researchers was that the many benefits to soil properties and productivity gained from continuous no-till would be lost with a tillage trip. Wortmann says the studies indicate any negative effects normally last less than 1 year. However, growers must also weigh the tillage cost and the increased risk of erosion until a crop canopy or residue cover is reestablished.

Yield Impact

Based on 35 trials where occasional tillage was evaluated, Wortmann found no yield effect in 72% of these studies with yield decreases showing up in only 7% of the cases. Yield increases with the remaining 21% of the cases were likely due to correcting a critical residue, soil structure or fertility problem. Wortmann says an occasional tillage trip is unlikely to be justified more than once every 5-10 years in any no-till fields. 

Some die-hard no-tillers will argue making one tillage trip will destroy years of no-till benefits. Maybe the Nebraska data indicates the anticipated disaster might not be as big a concern as you would have expected. But like most of our No-Till Farmer readers, I oppose using occasional tillage even once in long-term no-tilled fields. For me there are just too many no-till benefits that could be lost.