Aaron Daigh, NDSU Department of Soil Science
Jodi DeJong-Hughes, University of Minnesota Extension
Abbey Wick, NDSU Department of Soil Science

There are many advantages of reducing soil tillage for building soil health.  However, reducing tillage creates concerns of yield reductions due to cool and wet soils in the poorly-drained landscape that dominates much of North Dakota and the Red River Valley.  The objective of this study is to:

  1. monitor soil warming, water contents, and thermal properties under chisel plow, vertical tillage, strip till with shank, and strip till with coulters, and no tillage on various soil series with subsurface drainage or natural drainage,
  2. evaluate soil health and crop emergence and yields, and
  3. transfer information to producers through field days, videos, etc.

This is a multi-state effort, involving North Dakota and Minnesota and 2016 will be year two of a 4-yr field study. Four on-farm locations are under a corn-soybean rotation and rotate each year. At each location, the five tillage practices are demonstrated using full-sized equipment in plots of 40 or 66 feet wide by 1800 feet long in a replicated design. Soil series evaluated are Fargo silty clay, Lakepark clay loam, Barnes-Buse loams, Delamere fine sandy loam, and Wyndmere fine sandy loam. These soil series cover over 67 million acres of prime farmland in the Northern Great Plains regions.

During 2015, the strip till with either a shank or a coulter provided a comparable or slightly better alternative to the chisel plow for spring time soil warming and drying. Additionally, they conserved mild quantities of water in the areas between tillage strips that would be beneficial in years with little snowmelt or spring rains prior to seedling growth. The vertical tillage also conserved mild quantities of water but allowed the soil to dry much more than the no tillage system while also providing a mild temperature increase.

The locations with subsurface drainage did not enhance soil warming and drying as compared to the locations that did not require subsurface drainage. However, the subsurface drainage would have likely prevented even cooler and wetter conditions than if the subsurface drainage was not in place. Soil clay contents and water contents had a major impact on soil warming, as expected, and the differences among tillage practices were greatest under soils what were innately warmer.

Soil samples have been collected to determine soil health and are currently being analyzed in the laboratory. Crop residue cover, crop populations, yields, and yield patchiness were measured and are currently being statistically analyzed.

Three videos were produced in 2015 to introduce the study and preliminary findings to North Dakota producers. Information obtained during this first year was presented the Soil Health Field Day hosted by NDSU and the Tillage, Technology, and Residue Field Day hosted by UMN through a cooperative effort by NDSU and UMN Extension.