Brandt, S.A.

Sonntag, G.J.

Ulrich, D.

Wall, D.D.

Zentner, R.P.

English

eCommons@USASK

Effects of input level and crop diversity on energy use efficiency of cropping systems in the Dark Brown Soil Zone

University of Saskatchewan Research Archive

 - 341 - Effects of Input Level and Crop Diversity on Energy Use Efficiency of Cropping Systems in the Dark Brown Soil Zone  D.D. Wall1 , R.P. Zentner1, S.A. Brandt2, D. Ulrich2, and G.J. Sonntag1 1Semiarid Prairie Agricultural Research Centre, Box 1030, Swift Current, SK. S9H 3X2 2Scott Experimental Farm, Box 10, Scott, SK. S0K 4A0  INTRODUCTION  Declining commodity prices coupled with rapidly rising input costs are causing many producers in western Canada to question the merits of conventional high-input agricultural production systems.  In response, producers have become increasingly interested in extending and diversifying their cropping systems, and in adopting low-input and organic management practices.  However, little is known about the impacts of these land use changes on the requirements for non-renewable energy inputs and energy use efficiency.  OBJECTIVES  To study non-renewable energy inputs, energy output, and energy use efficiency of nine cropping systems, representing three levels of input usage [high (recommended rates of inputs required), reduced (reduced use of pesticides, fertilizers and fuel), and organic (non-chemical pest control, legume green manure, and later seeding date)], and three levels of cropping diversity (low crop diversity, diversified annual grains, and diversified grain/forage).  The paper draws on data from the first 6 years of a long-term field experiment being conducted in the Dark Brown soil zone at the Scott Experimental Farm.  MATERIALS AND METHODS  Experimental Data • Initiated in 1995 in the Dark Brown soil zone at the Scott Experimental Farm. • Data from the intial year (i.e. 1995) are excluded from the analysis because all crops were not yet in proper sequence and thus would not refelct the true treatment effects. • Crop Rotations:   - 342 - Crop diversity Input level Crop sequence1 LOW  (low diversity of High FT-W-W-FT-C-W            annual grains) Reduced LGM-W-W-FC-C-W  Organic LGM-W-W-LGM-C-W    DAG  (diversified using  High C-R-P-BM-FX-W            annual grains) Reduced C-R-P-BM-FX-W  Organic LGM-W-P-BM/SC-SCGM-C    DAP  (diversified using  High C-W-BF-O/BR&A-H-H            annual grains and Reduced C-W-BF-O/BR&A-H-H            perennial forages) Organic C-W-BF-O/BR&A-H-H 1  FT = tillage fallow, W = wheat, C = canola, LGM = lentil green manure, FC = chemical fallow, P = field pea, BM = malt barley, BF = feed barley, SC = sweet clover, SCGM = sweet clover green manure, R = fall rye, FX = flax, O = oats, BR&A = bromegrass-alfalfa, and H = hay.  Energy Analysis • All direct and indirect nonrenewable energy going into manufacture, formulation, packaging, transportation, maintenance and application of all inputs used in each production system were included. • Energy output was taken as gross energy content (as measured by bomb calorimeter) of harvested grain less seed requirements. • Energy use efficiency was calculated as: i) net energy produced (energy output minus energy input), and ii) ratio of energy output to energy input.  RESULTS AND DISCUSSION  Overall Annual Energy Performance  • Total annual production of each cropping systems varied greatly among years (Figure 1), reflecting the effects of growing season weather conditions on crop yields. • Annual total production was greatest in 1996, 1999, and 2000 when growing season precipitation was above normal, and lowest in the drier years of 1997 and 1998.   - 343 - Figure 1.  Average Annual Total Production  Overall Annual Energy Performance  • The energy performance of the production systems, differed greatly among years (Table 1). • Gross energy output, net energy production, and energy output/input ratio were highest in 1996 and lowest in 1998. • Total energy inputs were highest in 2000, intermediate in 1997 and generally similar from 1996, 1998, and 1999.  Table 1.  Mean Annual Energy Performance (MJ ha-1) Energy Parameter 1996 1997 1998 1999 2000 Gross Energy Output 35399 23396 17716 41689 30786 Total Energy Input 2739 2881 2627 2701 3903 Net Energy Production 32660 20515 15089 38988 26883 Energy Output/Input Ratio 12.9 8.1 6.7 15.4 7.9   Effect of Crop Diversity on Energy Performance  • Gross energy production ranged from 26621 MJ ha-1 for the DAP (with organic inputs) treatment to 59502 MJ ha-1 for DAG (with high inputs) (Table 2). • Overall, gross energy output tended to be highest for DAG, intermediate for LOW (17% less) and lowest for DAP (33% less) treatments. 0500100015002000250030001996 1997 1998 1999 2000High Reduced Organic - 344 - • Total energy input was highest for DAG, and lowest (and about equal) for DAP and LOW treatments(19% less). • Net energy production displayed similar trends as for gross energy output. • Energy output/input ratios were highest for DAG (with reduced inputs), and lowest for DAP (with high inputs).   Effect of Input Level on Energy Performance  • Gross energy production tended to be highest for High Input, intermediate for Reduced Input (15% less) and lowest for Organic (37%) treatments. • Non-renewable energy requirements were highest for High Input and Reduced Input treatments and lowest for Organic Input (about 50% less) treatments. • The energy Output/Input Ratio tended to be highest for Organic Input treatments, intermediate for High Input (24% less) and lowest for Reduced Input (41% less)   Effect of Energy Inputs by Crop Diversity  • As expected, the majority of the energy inputs used consisted of fertilizer and fuels. • These two categories comprised over two thirds of the total energy inputs for all three diversity treatments. • Fixed machinery energy was the third highest energy input, accounting for 18% to 22% of total energy inputs. • DAG required the greatest total energy input, followed by DAP and then LOW. Table 2.  Effect of Crop Diversity and Input Level on Energy Performance (MJ ha-1)5-Year AverageCrop Diversity Energy Parameter High Reduced Organic MeanDAG Gross Energy Output 59502 52854 37729 50028Total Energy Input 4145 3522 1635 3101Net Energy Production 55357 49332 36094 46928Energy Output/Input Ratio 17.8 15.3 21.5 16.1DAP Gross Energy Output 39726 34110 26621 33486Total Energy Input 2601 3403 1356 2453Net Energy Production 37125 30707 25265 31032Energy Output/Input Ratio 15.0 12.3 18.4 13.7LOW Gross Energy Output 52009 41819 30835 41554Total Energy Input 2658 3476 1514 2549Net Energy Production 49351 38343 29322 39005Energy Output/Input Ratio 16.6 8.7 19.5 16.350412 42928 31728 416893135 3467 1501 270147278 39460 30227 3898816.0 12.4 21.1 15.4Mean Energy Output/Input RatioInput LevelMean Gross Energy OutputMean Total Energy InputMean Net Energy Production - 345 - Effect of Energy Inputs by Input Level  • Non-renewable energy requirements were highest and similar for the High Input and Reduced Input treatments and lowest for the Organic Input treatment. • Savings in energy requirements for fertilizer and chemical in the Organic Input treatments were off-set somewhat by higher energy requirements for fuel. • Use of Reduced Inputs provided some savings in energy for fuels and lubricants.  However, fertilizer energy requirements were higher in proportion to total energy use than in the High Input treatments.              CONCLUSIONS  • Fertilizers (primarily N) and fuel were the major non-renewable energy inputs to all treatments, except organic treatments where fuel alone was the major energy input. • Gross and net energy production tended to be highest for DAG, intermediate for LOW, and lowest for DAP treatments. • Gross energy production tended to be highest for High Input and Reduced Input treatments and lowest for Organic Input treatments. • The use of Organic Input levels showed potential to reduce total energy inputs by up to 50% compared to High Input and Reduced Input treatments. • Non-renewable energy use efficiency was highest with Organic Input management.   ACKNOWLEDGMENT  Funding for this project was provided by NRCan under the Panel on Energy Research and Development (PERD) program.  DAGFertilizer41%Machine19%Fuel & Lube26%Chemical14%DAPFertilizer43%Machine21%Fuel & Lube26%Chemical10%LOWFertilizer38%Machine22%Fuel & Lube31%Chemical9%HighFertilizer45%Machine16%Fuel & Lube25%Chemical14%ReducedFertilizer54%Machine15%Fuel & Lube17%Chemical14%ReducedFertilizer57%Machine43%

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Effects of input level and crop diversity on energy use efficiency of cropping systems in the Dark Brown Soil Zone

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