by Linzy Carlson
In areas with high winter precipitation
accompanied by multiple freeze/thaw cycles, the potential for water erosion on
recently disturbed crop land increases dramatically. During a warm spell, the surface soil thaws and becomes
supersaturated while deeper soil remains frozen, preventing snowmelt and
rainfall from permeating the soil profile.
Consequently much of the winter precipitation is lost as runoff, taking with
it massive amounts of surface soil.
Because of their weather patterns, areas
of eastern Washington and western Idaho lose a great deal of soil each year to
winter water erosion on fall seeded cropland.
M.M. Mizuba and J.E Hammel (1996) looked at subsoil tillage as a method
of dealing with this problem. The idea
behind subsoil tillage is to create more macropores in the soil prior to
freezing. Then, after the soil is
frozen, the macropores are in place to carry water away from the surface to deeper
areas that are not frozen and can hold the water. Also, increased infiltration keeps water from saturating the
surface, which helps maintain soil structure.
Mizuba and Hammel employed a paratill to
disturb the subsoil of the experiment plot prior to seeding winter wheat. A paratill disturbs the subsoil with angled
shanks that lift the soil, breaking it along the natural fracture planes. They compared the results with the paratill
to those with deep ripping. They
concluded that both methods increase infiltration, while reducing water
erosion. Although both methods met the
primary goal, deep ripping seemed to cause water to percolate below the crop’s
root zone, taking fall applied nitrogen fertilizers with it. Therefore, they concluded that the paratill
was a better option in the situation they were working in.
The beneficial effects of the disturbance
wear off as the winter progresses.
Natural weathering settles the macropores and smoothes the soil surface,
leading to decreased infiltration and surface sealing. Despite this, the water and soil saved early
in the winter makes the practice economically feasible in areas where winter
water erosion is a major problem.
Journal of Soil
and Water Conservation.
Volume 56, Number 2
Title: “Infiltration rates in fall-seeded winter
wheat fields following preplant subsoil tillage”
Pages: 133-136
Authors: M.M.
Mizuba, J.E. Hammel
This note is part of the Agronomy Notes
series, a weekly news release and fact sheet series prepared by Dr. Jim Bauder,
Extension Soil and Water Quality Specialist at Montana State University. Past
Agronomy Notes can be viewed at http://AGNOTES.org/. For
additional information on this subject, for subscription (no charge) to this
Agronomy Notes series, or for questions about Agronomy Notes, Jim Bauder can be
contacted by E-mail at or by calling 406-994-5685 at MSU.
Categories: Erosion,
Tillage
Date: 2002