Dr. Clements et al., ENERGY ANALYSIS OF TILLAGE AND HERBICIDE INPUTS IN ALTERNATIVE WEED MANAGEMENT-SYSTEMS, Agriculture, ecosystems & environment, 52(2-3), 1995, pp. 119-128
In view of the movement toward alternative weed management systems in
crop production, the authors analyzed the energy efficiency of tillage
practices and herbicide use in alternative systems featuring reductio
ns in tillage and/or herbicide inputs. These systems were from an expe
rimental trial near flora, Ontario and a farm survey in southern Ontar
io, Canada. Because weed management represented only 20-25% of the ann
ual energy cost for systems using synthetic herbicides and fertilizers
, modifications in fertilizer use are more important for energy conser
vation than weed management. However, energy was conserved in alternat
ive weed management systems by elimination or reduction strategies for
tillage and/or herbicide use. Eliminating tillage was more energy eff
icient than eliminating herbicide use, and resulted in the two lowest
energy budgets for weed control among the 12 farms surveyed. Eliminati
on of herbicide use could conserve energy and maintain acceptable yiel
ds, particularly in conjunction with farmer experience, and were assoc
iated with the use of organic fertilizer and a smaller proportion of e
nergy-intensive crops such as corn. Low-input systems in which tillage
and/or herbicides were reduced but not eliminated were more efficient
in converting energy into yield than high-input systems, provided tha
t other inputs substituted for reduced inputs (e.g. mechanical inputs
instead of chemical inputs) were used in moderation. Thus, most altern
ative methods of weed control (e.g, reduced herbicide and tillage inpu
ts) are more energy efficient than conventional weed control practices
(e.g. broadcast application of herbicides at recommended rates).