by Jim Bauder

 

Wheat producers seem to be constantly interested in "ideas on the edge." You know, the type of things that might work, or might cause a small but significant change, and be economically rewarding. One such idea is deep ripping fall-planted wheat after fallow to improve infiltration and reduce erosion. This is the title of a Pacific Northwest Conservation Tillage Handbook Series article, Chapter 2 -Systems and Equipment No. 16, December, 1995, by W. Schillinger of WSU. Dr. Joe Pikul, formerly of the ARS center in Sidney, MT also wrote an interesting research article about this. Both of these articles have some interesting findings to report about DEEP RIPPING winter wheat.

Potential Benefits

Why even consider ripping, and what is it all about? Several researchers have investigated the effects of ripping winter wheat fields after fall growth to create trenches that will accept melting snow and to serve as mini detention basins that will trap sediment and snow on sloping soils that tend to erode with mid winter or early spring snowmelt runoff. Water runoff (valuable moisture) and soil loss from winter wheat fields are often severe during the winter when rain or snow melt occur on frozen soils. Anything to reduce runoff, prevent erosion, and capture a little extra moisture might be worth trying.

 

Details of the Study

In a 2-year study in eastern Washington, the WSU researchers deep ripped seeded silt loam wheat plots on excessively sloped land that had been seeded along the contour. The late fall operation ripped to a depth of 10 or 24 inches with 1-2" wide shanks with an attached rotary subsoil spreader spaced 12 or 20 feet apart.

Ripping significantly improved water infiltration into the soil to a depth of 6 feet as far as 3 feet down slope from the ripped channels. Generally speaking, grain yield was reduced in the row most disturbed (where the ripping occurred), but grain yield increased in the adjacent rows. On a whole-plot basis, there were no differences in grain yield between ripped and control treatments in either year of the study.

Results
  • There were significant differences in soil water content measured to 6' depth within 3 feet from the ripped slot, but there were no differences in water content 5' away from the ripped channel
  • .
  • Ripping was most effective when melting occurred at a
  • time when the soil was frozen.
  • Ripping significantly reduced soil loss by rill erosion during both dry and wet winters.

Ripping significantly reduced soil loss throughout the winter compared to control treatments where no ripping was done. Tilled or ripped channels generally stopped rills. Rate of soil loss in ripped plots, low throughout the winter, had increased by early spring, perhaps because the surface soil was saturated and tillage channels had filled with sediment by this time.

Bottom Line
Creating deep tillage channels on the contour when the crop is dormant in seeded winter wheat on sloping soils subject to spring-time water erosion has the following effects:
  1. Reduced soil loss by retarding rill erosion during both dry and wet winters.
  2. Increased water infiltration during wet winter
  3. No adverse effects on grain yield.