USDA’s Agricultural Research Service has conducted studies to determine how standing crop residues affect snow accumulation and soil water levels across entire fields. A USDA soil scientist studied two neighboring farms in the Palouse region in eastern Washington. Both have hilly topography – but one farm has been under continuous no-till management since 1999. The fields on the other farm were conventionally tilled. Snow depths, density and soil water storage were measured at hundreds of points across the fields on both farms for two years. The residue height at data collection points was also measured on the no-till fields. USDA says the findings show that no-till management can ensure blanket coverage of snow in the winter – which can help boost dryland crop productivity in the summer.
According to the study – standing wheat residue on the no-till farm significantly increased the amount and uniformity of snow cover across the entire field. Snow depths ranged from four to 39-inches – with an average depth of 11 inches. Snow depths on the conventionally tilled field ranged from zero to 56 inches – with an average depth of 8.5-inches. USDA notes the snow distribution pattern on the no-till farm made soil water distribution more uniform and increased soil water recharge rates. USDA’s soil scientist 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. This could increase winter wheat profits for regional farmers by an average of 30-dollars per acre and as much as 54-dollars per ridge-top acre.
According to USDA – producers affected by the 2012 drought might also benefit from using no-till to increase the amount and uniformity of snow cover on their fields. This would increase soil water recharge rates and soil moisture storage – which would facilitate the return of drought-stricken fields to their former productivity.