Agriculture Reference
In-Depth Information
One of the reasons no-till acreage in wheat-
dominated production systems has increased over
the past 5 years is the decreased labor and fuel
requirements of no-till production systems. Pre-
vious research indicated that savings from reduced
machinery, labor, tractor fuel, and repair costs
associated with no-till production practices were
negated by increased herbicide costs (Epplin
et al., 1983). However, the price of glyphosate
(480 g of emulsifi able concentrate per liter) has
declined from a US average of $12 per liter in
1999 to $5 per liter in 2005, thus reducing by
more than one-half the cost of herbicidal control
of summer weeds from harvest in June until
planting in September. Coupled with that, record
oil prices have resulted in drastic increases in
farm diesel costs. The primary labor and fuel
savings for a no-till wheat production system is in
seedbed preparation, especially in more intensive
production systems such as those used in Europe
(Fig. 4.3). Many producers view no-till wheat
production as a way of trading high-priced, con-
ventional practices burdened with high environ-
mental impact (e.g., tractor-engine emissions,
fuel consumption, carbon loss, and erosion from
tillage operations) for low-priced, low-environ-
mental-impact production practices.
Advances in equipment technology have
also increased adoption of no-till practices.
Drift-reducing nozzles have allowed greater use
of glyphosate in areas adjacent to susceptible
crops (Derksen et al., 1999). Another area that has
seen great advancements in no-till wheat produc-
tion systems has been in no-till drill design and
performance. Proper seedbed preparation can
dictate the effi ciency of all subsequent operations
performed throughout the year. Wheat sown into
a poorly prepared seedbed or with poorly cali-
brated equipment has little chance of obtaining
optimal yield potential. Stockton et al. (1996)
found that actual fi eld emergence of wheat was as
low as 30% and averaged 57% of viable seed.
They indicated that the primary reason for poor
emergence was poor control of seeding depth,
causing most seed to be sown too deep. Many
conventional wheat drills at the time lacked
linkage between the disk openers and press
wheels.
Fig. 4.3
Fuel and labor inputs are reduced by almost
50% when conservation-tillage measures are introduced into
an intensive wheat production system. (Adapted from
Lithourgidis et al., 2006.)
Wheat drill design and performance has
improved dramatically since the work of Stockton
et al. (1996). Most conventional drills now have
the press wheel directly connected to the disk
opener as a standard design and seeding depth is
more precise and consistent. The fi rst no-till
drills were essentially heavy conventional drills or
conventional drills with a coulter-caddy attach-
ment. The results from these drills in heavy
residue such as maize stalks were often undesir-
able. Common problems included poor soil pen-
etration and inadequate seed-to-soil contact (see
Color Plate 8). Modern drills, however, can
deliver consistent and even seed distribution in a
wide range of seedbed conditions, from true no-
till to minimum till to conventional till.
