Profit is likly the most important factor that influences a grower’s decision to adopt conservation practices such as no-till. While numerous studies have shown higher yields and profits when moving away from extensive tillage practices, other studies have shown a reduction in yields when shifting to no-till.
Researchers at the University of Tennessee recently reviewed numerous research studies to evaluate the impact of crop yields by switching from extensive tillage to no-till. The researchers looked at factors such as crop species, the year the experiment began, the time since conversion from doing tillage, annual precipitation, soil texture and geographic location that were evaluated in research plots.
They analyzed data gathered from 30 years of referred research journal articles based on 442 experiments where no-till was compared with conventional tillage, strip-till, ridge till and mulch-till. This included 92 locations across the U.S. where data was evaluated for corn, soybeans, wheat, grain sorghum, oats and cotton.
Soils Make A Difference
“This analysis indicates that no-till does not perform as well as tillage on a sandy-textured soil,” says Tennessee researcher Dustin Toliver. “For wheat and soybeans on a sandy-textured soil, the likelihood of lower no-till yields than tillage yields was larger than on a loamy-textured soil.”
The yield differences between no-till and tillage in silt soils was less than the differences found with loam soils. This indicates no-till performs better on well-drained soils, but does not yield as well with finely textured or poorly drained soils such as silty soils.
Differences between no-till and tillage yields with clay and sandy soils were no different than the results with loam soils when all other factors were equal. A potential explanation for lower no-till yields with sandy soils is that the lower water-holding capacity can be critical in dry years, along with nitrogen-leaching concerns.
The amount of time after the conversion to no-till improved the probability for higher no-till yields with both soybeans and cotton. The analysis also indicated there might be more downside associated with no-till in regions where annual rainfall is higher.
Moisture Makes A Difference
Increased soil moisture from residues left in the field was the most common explanation for increased no-till sorghum and wheat yields. The differences between no-till and tillage were larger with grain sorghum than with corn.
Toliver says the research indicated there can be favorable yields and less yield risk with no-till in the more humid climates and warmer soils of Southeastern U.S. Yet, it’s interesting to note that there’s been much wider no-till acceptance in many other regions.
These findings support the idea that crop, soil and climate factors can have a huge impact on no-till yields.Yet the value of no-till in your fields will have a bigger impact on yields and profits.