Conservation tillage practices
have been widely adopted for agronomic crop production, yet most vegetable
growers continue to use intensive tillage for seedbed preparation.
Benefits of conservation tillage included, reduced equipment and labor
costs, reduced soil erosion, improvements in soil quality, and in
some situations, increased yields.
Strip tillage is a form of conservation tillage that involves cultivation
of narrow bands, or strips in the row area, separated by bands of
undisturbed soil. Strip tillage has the potential advantages of providing
a suitable seedbed for vegetable crop establishment while leaving
surface residues in the inter-row area to reduce soil erosion. Equipment
for strip tillage has usually consisted of a modified rototiller (rotary
strip tiller) or a subsoiling shank and fluted coulter system (shank/coulter
system).
Yield response of vegetable crops to strip tillage has been variable.
In Pennsylvania, studies have shown strip tillage systems reduced
snap bean yields compared to the conventional tillage in all three
years of the trail, and reduced snap bean yields by 20% compared to
conventional tillage when planted into rye cover crop mulches in an
Illinois study.
In studies involving cabbage in Virginia and tomatoes in Ontario,
Canada, no differences in yield were observed between strip and conventional
tillage systems.
This study reported herein was conducted to develop and evaluate strip
tillage systems for sweet corn production in the Willamette Valley
of western Oregon.
Although this study focused on using strip tillage for sweet corn
production, Oregon growers have successfully used this system for
squash and transplanted broccoli. In 2001, eight vegetable growers
purchased or manufactured strip tillage machines and planted more
than 1200 ha or vegetable crops using strip tillage. The rapid adoption
of strip-tillage systems in western Oregon has demonstrated the potential
for vegetable production. However continued research is needed on
the impact of strip tillage on soil moisture, irrigation requirements,
and symphylan populations.
Two strip tillage systems for sweet corn production were compared
to conventional tillage systems in western Oregon. A power take-off
rotary tiller configured to till six rows per pass was used in 1997
and 1998; a shank/coulter strip tillage machine was used in 1999 and
2000. A pair t test experimental design and used in field-scale, on-farm
research with eight replications in 1997-98 and 12 replications in
1999-2000. Sweet corn was harvested using the participating growers’
corn pickers and yield was determined. A subset of the participating
growers recorded types of machinery and labor for tillage operations
and total costs were computed for each tillage system. The rotary
strip tillage system produced 900 kgÌha-1 greater corn yields
(P=0.11) than conventional tillage. The shank/coulter strip tillage
system produced yields comparable to conventional tillage (p=0.95).
The rotary strip tillage system reduced total tillage costs by an
average of $38.50/ha compared to conventional tillage (P=0.03) and
reduced machinery operating time by 0.59 hÌha-1 (P=0.01). The
shank/coulter strip tillage system reduced tillage costs by $36.50/ha
compared to conventional tillage (P=0.003) and reduced machinery operating
time by 0.47 hÌha-1 (P=0.001). Slugs damaged corn in several
strip tillage fields requiring the used of slug bait to prevent economic
damage. Herbicides used in conventional tillage systems were generally
effective in the strip tillage systems. Mechanical cultivation with
standard cultivating equipment was more difficult in some of the strip
tillage fields with heavy cover crop residue.
