Effects of input management and crop diversity on non-renewable energy use efficiency of cropping systems in the Canadian Prairie

• Published in: European journal of agronomy 2011-02, Vol.34 (2), p.113-123
• Main Authors: Zentner, R.P., Basnyat, P., Brandt, S.A., Thomas, A.G., Ulrich, D., Campbell, C.A., Nagy, C.N., Frick, B., Lemke, R., Malhi, S.S., Fernandez, M.R.
• Format: Article
• Language: English
• Subjects: agrochemicals; agroecosystems; Agronomy. Soil science and plant productions; Annual grains; application rate; Biological and medical sciences; conservation tillage; conventional tillage; crop management; crop residues; crop yield; Cropping systems; Cropping systems. Cultivation. Soil tillage; Crops; dryland farming; energy balance; Energy inputs; Energy output; energy use and consumption; Energy use efficiency; fallow; farm inputs; Forage crops; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Generalities. Cropping systems and patterns; land management; mineral fertilizers; nonrenewable resources; organic production; profitability; species diversity; sustainable agriculture
• ISSN: 1161-0301; 1873-7331
• DOI: 10.1016/j.eja.2010.11.004

▶ Organic practices use 50% less non-renewable energy. ▶ Conventional high-input cropping systems maximize calorimetric energy output. ▶ Energy use efficiency is greatest for grain-forage rotations with organic management. Although producers’ prime objective may be to increase net returns, many are also interested in conserving and enhancing the quality the soil, water and air resources through adopting more environmentally friendly production practices. This study compared non-renewable energy inputs, energy output, and energy use efficiency of nine dryland cropping systems comprised of a factorial combination of three methods of input management [high (HIGH), i.e., conventional tillage plus full recommended rates of fertilizer and pesticides; reduced (RED), i.e., conservation tillage plus reduced rates of fertilizer and pesticides; and organic (ORG), i.e., conventional tillage plus N-fixing legumes and non-chemical means of weed and pest control]; and three crop rotation systems with varying levels of cropping diversity [a fallow-based rotation with low crop diversity (LOW); a diversified rotation using annual cereal, oilseed and pulse grains (DAG); and a diversified rotation using annual grains and perennial forages (DAP)]. The study was conducted over the 1996–2007 period on a Dark Brown Chernozemic soil (Typic Boroll) in the Canadian Prairies. As expected, total direct plus indirect energy input was the highest for the HIGH and RED input treatments (3773 MJ ha −1 year −1), and 50% less for ORG management. Most of the energy savings came from the non-use of inorganic fertilizers and pesticides in the ORG management treatments. Further, total energy use was the highest for the DAG treatments (3572 MJ ha −1 year −1), and similar but about 18% lower for the DAP and LOW crop diversity treatments compared to DAG. Thus, overall, the HIGH/DAG and RED/DAG systems had the highest energy requirements (4409 MJ ha −1 year −1) and ORG/DAP had the lowest (1806 MJ ha −1 year −1). Energy output (calorimetric energy content) was typically the highest for the HIGH input treatments (26,541 MJ ha −1 year −1), was about 4% less with RED, and 37% less with ORG management. The latter reflected the lower crop yields obtained with organic management. Similarly, energy output was the highest for the DAP treatments (25,008 MJ ha −1 year −1), about 5% less for DAG, and 20% less for the LOW crop diversity treatments. The higher energy output with the DAP treatments largely reflect