Frost tillage was researched as a potential soil management option in the Northeastern USA. Research on this tillage method was based on anecdotal information on its benefits from farmer's experience. A three-year study was initiated on a silt loam soil to investigate the weather and soil physical conditions that lead up to frost tillage conditions. From this, it was determined that these conditions occur during initial soil freezing without snow precipitation when the frost depth is 3-8 cm. Upward water fluxes lead to significant soil drying under the frozen layer and generate very favorable tillage conditions when the frozen layer is still sufficiently thin to be ripped by a tillage tool. Agronomic tests were conducted on several soil types to verify the applicability of the method. A potential barrier to adoption of the method was the lack of predictability on a seasonal basis (i.e., how many frost tillage opportunities will occur during any given season?). Quantitative information was required on the expected frost-tillable days in various parts of the Northeast. Criteria were developed for frost tillage conditions based on frost depth and surface conditions (snow cover, etc.). These were entered into a one-dimensional heat flow model that estimates depth of soil freezing based on air temperature and snow cover data (DeGaetano et al., 1996). Simulations were conducted by the Northeast Regional Climate Center for 200 weather stations across the region, resulting in probability maps for frost tillage conditions which may be used by farmers and crop advisors as a guideline for seasonal frost tillage opportunities. Simulation results indicate that frost tillage opportunities in the Norteast are generally more probable in the Great Lakes and Mid-Atlantic regions, and are less likely in Northern New England.
Harold van Es, Associate Professor Soil and Water Management Department of Soil, Crop, and Atmospheric Sciences Cornell University Ithaca, NY 14853-1901 phone: 607/255-5629 fax: 607/255-6143 E-mail: hmv1@cornell.edu