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PNW CONSERVATION
TILLAGE HANDBOOK SERIES
Chapter 2 - Systems and Equipment, No. 3, Fall 1988
A
Strip-till Planting System for No-till Fallow
Don Wysocki
No-till chemical
fallow can provide better protection against water and wind erosion than
traditional summer fallow. However, several problems are associated with
chemical fallow systems. Among these problems are: increased difficulty
with fertilizer application and seeding, plugging of equipment, delayed
seedling emergence and uneven stands. These problems are addressed in
the design of several no-till grain drills. Some of these drills use large
heavy coulters, while others use shanks or chisels to open untilled soil
for placement of seed and fertilizer, One method of no-till planting that
is being researched by Floyd Bolton of the Crop Science Department, Oregon
State University, is the rotary strip-till planter.
The strip-till system
combines seedbed preparation, fertilizer and herbicide application, and
seed placement into one field operation. The seedbed is prepared by roto-tilling
strips 4 inches wide and spaced 16 inches apart. Depth of tillage can
be varied to a maximum of 7 inches depending upon the depth to moist soil.
A representation of the strip tillage system is shown in Fig. 1. According
to Bolton the system provides effective erosion control because only 25
percent of the surface is disturbed and the residue between the rows remains
intact. Also the tilled seed rows help to collect and infiltrate surface
runoff.
Fig. 1. Rotary strip-till operations (a) herbicide fertilizer band,
(b) tilled strip, (c) soil from tilled strip deposited onto untilled area
and (d) seed placement (Bolton, OSU).
Bolton's strip-till planter has been in development since1977. After each
planting season, its operation was evaluated. Adjustments and modifications
were then made to improve its performance. The current version, which
has performed well for the past 2 years, is being considered for production
by a commercial manufacturer. The present unit consists of a heavy duty
tiller modified to achieve the desired row spacing and area of tillage.
Double disk openers are mounted on a tool baron the rear of the unit.
Seed is distributed from a standard drill box by a hydraulic motor. A
spray boom attached to the ti-ont of the planter applies liquid fertilizer-herbicide
materials. Each double disk also has tubes for application of liquid starter
fertilizer or water into the seed zone. The experimental unit was constructed
8 feet wide for ease of transport. However, the manufacturer is proposing
widths up to 20 feet.
Bolton has evaluated the performance of the strip-till planter from several
aspects. Data in Table 1 area comparison of performance of the unit under
different levels of surface residue. The strip till planter performed
equally well under these different conditions which demonstrates that
it can operate successfully in heavy crop residues. Bolton points out
that the difference of 10 bushels under the highest level of residue was
not statistically different from the other yields, He attributes the difference
to lack of nitrogen because all plantings received the same rate of fertilizer
nitrogen. Bolton compared the strip-till method of fertilizer application
(liquid between the rows) to broadcasting before seeding (Table 2). Spraying
liquid fertilizer between the rows was equivalent to broadcasting. However,
using liquid fertilizer allows simultaneous application of herbicide solutions,
thus saving extra application costs. Bolton has further evaluated the
system in regard to herbicide rates, Cercosporella foot rot and
water injection.
The strip-till system has produced grain yields of winter wheat equal
to other systems over the past 6 years. A comparison is shown in Table
3. All systems were in a wheat-fallow rotation. The strip-till system
was chemical fallowed; the others were conventionally fallowed. All systems
received equal rates of nitrogen and seed. Bolton explains the slightly
lower yield observed in the stubble mulch system was probably caused by
grassy weeds. The conventional and strip-till systems were observed to
have fewer grassy weeds during crop growth than the stubble mulched system.
Table 1. Seedling
emergence and grain yield of strip-till plantings under different levels
of surface residue, Moro, OR (Bolton, OSU).
|
Residue
(lb/acre)
|
Seeding
Emergence
21
days after planting
(%
of seed planted) |
Grain
yield
(bu/acre)
|
| 0-residue
remove |
73
|
63.5
|
| 6,958-standing
stubble |
72
|
64.5
|
| 13,915-standing
stubble
+ added residue
|
73
|
54.3
|
Table 2. Response
of strip-till plantings to different methods of nitrogen fertilizer
application, Moro, OR (Bolton, OSU).
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