The USDA studied snow accumulation on no-till versus conventionally tilled winter wheat fields.
A smooth blanket of snow in the winter can help boost dryland crop productivity in the summer, and according to USDA research, no-till management is one way to ensure that blanket coverage.
Through a series of studies on two neighboring farms in Washington, soil scientist David Huggins, with USDAâ€™s Agricultural Research Service, determined how standing crop residues affect snow accumulation and soilâ€™s water levels across entire fields. Both farms have the hilly topography typical of the Palouse region in eastern Washington, but much of one farm has been under continuous no-till management since 1999, while the fields on the other farm were conventionally tilled. For two years, snow depths, density and the soilâ€™s water storage were measured manually at hundreds of points across the fields on both farms. Residue height at data collection points was also measured on the no-till fields.
Huggins found that standing wheat residue on the no-till farm significantly increased the amount and uniformity of snow cover across the entire field. Snow depths on the no-till field ranged from 4 to 39 inches, with an average depth of 11 inches, while snow depths on the conventionally tilled field ranged from 0 to 56 inches, with an average depth of 8.5 inches.
The snow-distribution pattern on the no-till farm made the soilâ€™s water distribution more uniform and increased the soilâ€™s water-recharge rates. The more uniform snow distribution under no-till was particularly apparent for ridge tops and steep, south-facing slopes where there was typically 4 to 8 more inches of snow than on conventionally tilled fields.
Huggins calculated that the greater storage of soil water in no-till systems could increase winter wheat yield potential by 13 bushels per acre on ridge tops, six bushels per acre on south-facing slopes and three bushels per acre in valleys. As a result, regional farmers could increase their winter-wheat profits by an average of $30 per acre and as much as $54 per ridge-top acre under no-till management.
Producers affected by the 2012 drought might also benefit from using no-till methods to increase the amount and uniformity of snow cover on their fields. This would increase soilâ€™s water-recharge rates and moisture storage, which would facilitate the return of drought-stricken fields to their former productivity.
Results from this work were published in 2011 in Transactions of the ASABE.