In agriculture, soil is everything. It's a living medium that interacts with a farmer's crops and fosters growth. No-tillage farming is practiced with this in mind, helping to conserve soil quality by utilizing herbicides. Since 1946, when the first successful selective herbicide was commercially released in the United States, a growing number of farmers have been ditching their plows for the more sustainable no-till approach.
No-tillage farming presents a number of advantages to farmers, including reduced labor costs, improved soil quality, decreased erosion, and increased soil organic carbon. In spite of these advantages, no-tillage is practiced on only 35% of U.S. cropland. It is commonly perceived that no-tillage results in reduced yields compared to conventional tillage practices. Current available research paints a mixed picture of the comparison between the two methods.
While past studies have usually focused on one or two crops in a specific region, more research is needed to evaluate differences in yields on a much larger scale. Researchers from the University of Tennessee have explored whether no-tillage yields are higher or lower than tillage yields for a variety of crops across the U.S., and the risks involved with low no-tillage yields.
The team analyzed data from 442 studies, ranging from the 1960's when no-tillage was still new and widely unused, to the 2000's when no-tillage had matured and become a more popular practice. Their analysis considered factors that may influence yields, such as crop type, average annual rainfall, and the location of the studies.
Results from this study show that yields of no-tillage and tillage practices are dependent on soil texture, crop type, rainfall, and geographic region. For example, no-tillage performed better than tillage in the warmer and more humid climates of the southeastern U.S. Using no-tillage in this region also reduced the risk of decreased yields.
With the exception of corn and cotton grown in the southeastern U.S., no-tillage generally performed poorly on sandy soils. High annual rainfall increased the risk of lower no-tillage yields compared to tillage yields. Overall, crops such as sorghum and wheat performed well under no-tillage, but the differences were mostly attributed to the growing environment and soils of the different regions.
The results of this study help address the gaps in the current knowledge between no-tillage and tillage yield performance. Although thorough, the study did not represent all crops and soil types in each region after compiling data for the analysis. The research team suggests that funding for future research on crops and soils in regions where tillage data is lacking could help fill in these gaps, and determine if no-tillage yields can be improved.
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