Answer: True. No-till soils have better structure, higher organic matter content and greater biological activity than tilled soils, which makes them more resistant to compaction, Duiker says. However, “compaction can still have significant negative effects on the productivity of no-till soils.” In a Pennsylvania study, for example, no-till soil was compacted by a 30-ton manure truck with tires inflated to 100 psi. Corn yields fell by 30 bu./acre in a dry year and 20 bu./acre in a wet year, compared to yields in un-compacted no-till fields.

In Ohio State University’s continuing compaction research, annual subsoiling is being compared to continuous no-till. The plots have been compacted every three years since 2002. In the compacted plots (20-ton/axle load), no-till corn yields averaged 7% higher than subsoiled treatments, and soybean yields were 5% higher. The uncompacted control plots – no-till, only light traffic – yielded about 10% better than no-till compacted plots.