Hello to all...
While full energy accounting of agricultural systems is a rare endeavor
these days.. the western Canadians appear to be both improving the energy
efficiency of their cropping systems and doing some studies to document
their progress.
The following was excerpted from
http://www.ag.usask.ca/centres/csale/Pubs/GHG/Ross/ross.htm
****************************************************************************
**************
Agricultural production in western Canada relies heavily on the input of
nonrenewable energy. Hopper (1984) estimated that it took 4.5 MJ of
nonrenewable energy inputs to produce one kg of wheat in 1981. Zentner et
al. (1998a) report that they required 4.4 MJ of nonrenewable energy inputs
to produce one kg of wheat. Total requirements for nonrenewable energy
inputs remains high and much of this energy consumption results from the
heavy use of fuels in farm mechanization as well fertilizers and
herbicides. Conventional tillage has a higher fuel energy requirement on a
per hectare basis when compared with zero tillage practices. Henry (1994)
reports that for a diversified wheat-pea-wheat-canola rotation in the
black soil zone energy expended in the form of fuel on a per hectare basis
for the four year rotation was 8205 MJ under zero tillage and 12306 MJ
under conventional tillage. By reducing the use of mechanical tillage the
fuel energy savings are clear. The energy on a per hectare basis expended
on herbicides under zero tillage was 2348 MJ compared to 1434 MJ under
conventional. Zentner et al. (1998a) report that for a fallow-wheat system
on the brown soil zone, fuel energy expended under zero tillage averaged
986 MJ/ha under conventional tillage and 667 MJ/ha. The energy expended on
herbicides averaged 287 MJ/ha under conventional tillage and 634 MJ/ha
under zero tillage. Zero tillage systems do reduce the use of energy in
the form of fuel but part of this savings can be offset the in increase in
energy use in the form of herbicide. Zentner et al. (1993) also show that
for a fallow-wheat rotation in the brown soil zone fuel consumption
decreases from 33 L/ha under conventional tillage to 26L/ha under zero
tillage. It is important to note that nonrenewable energy in the form of
fertilizer can account for up to 50 percent of the total energy input
required in a crop production system (Zentner et al. 1998). Reducing
energy inputs in the form of fertilizer has the potential to create a
large energy savings. More research is needed to determine the suitability
of present nitrogen fertilizer recommendations for use in zero tillage
production systems since they were originally developed for use in
conventional tillage systems.
Zantinge et al. compared input use for conventional tillage, reduced
tillage, mulch tillage and no-till for continuous corn production in
southern Ontario. Because conventional tillage uses more field operations
per hectare per crop cycle, more fuel is required. According to their
data, conventional tillage consumes 58.2 litres of fuel per hectare per
year. No-till used only 28.4 litres per hectare per year. But the no-till
system required three times more herbicide and this is an energy intensive
input. Swanton and Clements have documented the improvements in energy
productivity in Ontario crop production between 1975 and 1991. According
to their data conventional tillage corn production used 508 litres of
diesel fuel equivalent per metric ton of corn produced in 1975. This had
fallen to 319 litres by 1991. Most of the gain came about through more
efficient use of fertilizer and reduced energy embodied in plant protection
products. Energy use in soybeans followed a similar pattern, with energy
inputs of 174 litres of diesel fuel equivalent per metric ton of grain
produced in 1975 but only 95 being used in 1991. Overall, Swanton and
Clements estimate that improvements in energy productivity reduced overall
energy use in corn production in Ontario by 24 percent between 1975 and
1991 even though production increased by 60 percent during that time period.
Henry, S. (1994). The energetics of cropping systems: a study of two crop
rotations utilizing conventional and zero tillage production methods.
Advanced Crop Production Project. Final Report.
Hopper, G.R. (1984). The energetics of Canadian prairie wheat production
1948-1981. Proceeding of Energex 1984: Energy Developments, New Forms,
Renewables, and Conservation. pp. 677-683.
Swanton, C. J. and Clements, D. (1995). Using Less Energy to Grow More
Corn and Soybeans Agri-food Research in Ontario – Special Edition, July,
pp.7-10.
Zantinge, A.W., Stonehouse, D.P. and Ketcheson, J.W. (1986). Resource
Requirements, Yields and Profits for Monocultural Corn with Alternative
Tillage Systems in Southern Canada. Soil and Tillage Research 8(1986):201-209.
Zentner, R.P., McConkey, B.G., Stumborg, M.A., Campbell, C.A. and Selles,
F. (1998a). Energy performance of conservation tillage management for
spring wheat production in the brown soil zone. Semiarid prairie
Agricultural Research Centre. Final Report.
Joel
Joel Gruver
Visiting Faculty
Principia College
Elsah, Illinois 62028
(618) 374 - 5289
jgruver@principia.edu
To Unsubscribe: Email majordomo@cals.ncsu.edu with the command
"unsubscribe sanet-mg". If you receive the digest format, use the command
"unsubscribe sanet-mg-digest".
To Subscribe to Digest: Email majordomo@cals.ncsu.edu with the command
"subscribe sanet-mg-digest".
All messages to sanet-mg are archived at:
http://www.sare.org/san/htdocs/hypermail
This archive was generated by hypermail 2b29 : Mon Jul 03 2000 - 12:00:35 EDT