Sustainability

Science Library

Agricultural Energy Use

1.

Decoding your fuel bill: What is your farm’s real energy bill?

Summary

This short article by researchers from Agriculture and AgriFood Canada and the University of Saskatchewan was published in 2008 in the peer-reviewed online journal Prairie Soils and Crops. It focuses on energy use in prairie agriculture.

The article first provides the historical background of energy use in prairie agriculture, beginning with the use of horses and oxen for power, followed by the mechanization of farming in the 1930s and 1940s, to the current trend of decreased tillage and increased fertilizer use. The major sources of energy use on prairie farms are reviewed: fertilizer, herbicides, and fuel to power and manufacture farm equipment.

Growing pulses and other legumes is highlighted as a way of reducing the nitrogen fertilizer requirement in agriculture. A pulse crop saves energy by producing nitrogen for itself and reducing the nitrogen requirement for subsequent crops. It also requires less energy to grow because there is no energy used to apply fertilizer. Overall, producing pulses requires only about half the energy of a cereal crop like wheat or barley.

Full Document
Smith, E. G., Zentner, R. P., Nagy, C. N., Khakbazan, M. and Lafond, G. P. Decoding your fuel bill: What is your farm’s real energy bill?

http://www.prairiesoilsandcrops.ca/display_article.html?id=15

2.

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

Summary

Published in 2011, this peer-reviewed article in the European Journal of Agronomy compared the energy use of different cropping systems in Saskatchewan. Each cropping system consisted of one of three levels of inputs (i.e. fertilizer, pesticide, and tillage) and one of three crop rotations, for a total of nine different cropping systems. The three input levels were high, reduced, or organic, while the crop rotations had low, medium, or high diversity. Crops used to diversify the rotations included pulses (lentils and peas).

Results showed that unless legumes such as pulses are included in crop rotations, reliance on non-renewable energy remained high. The authors conclude that the best way to diversify the traditional cereal monoculture crop rotations of the Canadian prairies while improving energy use efficiency is to use legume crops including pulses and forages.

Full Document
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. and Fernandez, M. R. 2011. Effects of input management and crop diversity on non-renewable energy use efficiency of cropping systems in the Canadian Prairie. European Journal of Agronomy. 34: 113-123.
http://www.sciencedirect.com/science/article/pii/S1161030110001073
3.

Effects of tillage method and crop rotation on non-renewable energy use efficiency for a thin Black Chernozem in the Canadian Prairies

Summary

This study compared different crop rotations and tillage practices to see how they affect non-renewable energy use. It was published in the peer-reviewed journal Soil and Tillage Research in 2004.

The experiment included three different crop rotations and three different tillage practices. The three crop rotations were: 1) monoculture wheat; 2) wheat and flax; and 3) wheat, flax and peas. Each rotation was grown with conventional, minimum, or zero tillage practices. Energy use was determined by adding all the non-renewable energy used to manufacture, package, transport, maintain, and apply all inputs (such as fertilizer, fuel, and pesticide). Energy use efficiency was measured in three different ways: 1) the amount of grain produced per unit of energy input; 2) the ratio of energy output to energy input; and 3) the net energy produced (i.e. the energy produced in the harvested crop, minus the energy required to produce it).

After 12 years, the study showed that energy use efficiency was highest for the rotation that included peas. Non-renewable energy inputs required by peas were lower than flax or wheat. The addition of both peas and flax to the wheat-based crop rotation reduced total energy use by 13% compared to the rotation that added flax only. Growing wheat after another wheat crop required 8% more energy than if wheat was grown after peas. Improved energy use efficiency was attributed to the nitrogen supplied by the pea crop, reducing the need for added nitrogen fertilizer. Energy use efficiency was also improved when minimum or zero tillage practices were used to produce rotations that included peas or flax; however, tillage practices had no effect on energy use in monoculture wheat rotations.

This study confirms that adding peas to crop rotations can increase the efficiency of energy used in agriculture on the Canadian Prairies.

Full Document
Zentner, R. P., Lafond, G. P., Derksen, D. A., Nagy, C. N., Wall, D. D., and May, W.E. 2004. Effects of tillage method and crop rotation on non-renewable energy use efficiency for a thin Black Chernozem in the Canadian Prairies. Soil & Tillage Research. 77: 125-136.
http://www.sciencedirlifeect.com/science/article/pii/S0167198703002538
4.

Nitrogen and Food Production: Protein for Human Diets.

Summary

This peer-reviewed article is unique because it connects the science behind nitrogen fertilization with its impact on world hunger as well as the environment. It focuses on the importance of efficiently using nitrogen to reduce malnutrition. It was published in 2002 in AMBIO: a Journal of the Human Environment.

Because nitrogen is a major building block of protein, it is an essential input in order to produce protein for human diets. The nitrogen can originate from manure, legume crops such as pulses, or from nitrogen fertilizer. This article reviews the cycling of nitrogen in soil, water, and air, as well as the ways in which it is lost after being applied to crops. It then explains how agriculture was transformed when nitrogen fertilizer was first produced by the Haber-Bosch process in 1909. An overview of human protein needs is given and typical diets around the globe are summarized. The relationship between nitrogen fertilizer use and malnutrition is explained.

The article concludes with ideas for reducing global hunger without increasing the environmental impact of nitrogen fertilizer. Malnutrition can be decreased by modifying diets to focus on high-quality protein, and by using management strategies to more efficiently use nitrogen.

Full Document
Smil, V. 2002. Nitrogen and Food Production: Protein for Human Diets. AMBIO. 31(2) 126-131.
http://phad.cc.umanitoba.ca/~vsmil/pdf_pubs/Nitrogen%20and%20Food%20Production.pdf
5.

Energy use in American food production.

Summary

This essay was written in 2009 by Michael Minn, a PhD student in geography at the University of Illinois. It provides an overview of how energy is used in American agriculture. While there is no specific focus on pulses, it provides context in terms of the “big picture” of American energy use.

Energy use by Americans for food is about 12 to 17% of total American energy use, and the research and calculations used to arrive at this total are explained. Energy use from planting the crop to its final destination at the dinner table is discussed in detail. The essay first examines on-farm energy use including the production and use of farm chemicals (fertilizers and pesticides), the manufacture of machinery, and fuel to run machinery and irrigation equipment. The energy used to process and package food and transport it to the grocery store is then discussed. The energy required to operate food retail services and for household storage and preparation of food is also considered. Finally, the energy associated with imported food is summarized. The energy used to produce bottled water is also covered.

The paper then looks at specific food items as “case studies” to compare their energy use, including grains, meat, seafood, and beer. The author concludes by speculating about what the impact of rising energy costs would mean for American food consumption and lifestyles.

Full Document
6.

Optimising biological N2 fixation by legumes in farming systems.

Summary

This 2003 article in the peer-reviewed journal Plant and Soil summarizes research projects conducted by the United Nations Food and Agriculture Organization from 1972 to 1998. Research projects were conducted in both developed and developing countries, focusing on the ways in which the nitrogen contribution of pulses and other legume crops can be maximized.

The reasons why legumes and pulses are central to sustainable farming are explained, and then the methods for measuring the amount of nitrogen they produce are discussed in detail. Methods of enhancing the nitrogen production of legumes are then outlined.

Research has shown that there is enough genetic variation in many different legume crops to allow for plant breeding to improve their nitrogen-producing ability. The symbiotic rhizobia microbes that help pulses produce nitrogen could also be bred to be longer-lasting and more effective. In addition, the methods by which symbiotic rhizobia microbes are applied to pulse crops could be improved. Crop management to enhance soil quality and water availability is also important to allow the nitrogen added by the legume to be used by subsequent crops.

Full Document
Hardarson, G. and Atkins, C. 2003. Optimising biological N2 fixation by legumes in farming systems. Plant Soil. 252: 41-54.
http://www.springerlink.com/content/q48516nvk5m45572/  

 

Agricultural Greenhouse Gases / Carbon footprint

1.

Emissions of N2O and NO from fertilized fields: Summary of measurement data

Summary

This Dutch study, published in the peer-reviewed journal Global Biogeochemical Cycles in 2002, summarizes over 800 measurements of nitrous oxide emissions from fertilized agricultural fields around the world. The goal of the study was to provide information so that more accurate models to predict nitrous oxide emissions can be developed. The study looked at three factors that affect nitrous oxide emissions: soil conditions, crop and fertilizer management, and measurement techniques.

The study found that fertile soils tend to have higher nitrous oxide emissions, as do clay soils, acidic soils, and poorly drained soils. Because soil conditions vary over the landscape, so do nitrous oxide emissions, which creates “hot spots” of emissions. The study found that there is a strong increase in nitrous oxide emissions when nitrogen fertilizer or nitrogen-containing manure is used. Nitrogen fixing legume crops were found to have similar nitrous oxide emissions as fertilized non-legume crops, although most studies were focussed on soybeans or alfalfa. The way in which nitrous oxide is measured in terms of frequency and length of time is also important. For example, nitrous oxide emissions resulting from fertilizer use will continue for more than one growing season, so measurements that include only one growing season will underestimate nitrous oxide emissions.

This study adds to the information needed to continuously improve estimates of nitrous oxide emissions.

Full Document
Bouwman, A.F., Boumans, L.J. and Batjes, N.H. 2002. Emissions of N2O and NO from fertilized fields: Summary of measurement data. Global Biogeochemical Cycles. 16: 1058-1071.
http://www.agu.org/pubs/crossref/2002/2001GB001811.shtml
2.

Nitrous Oxide Emissions from a Northern Great Plains Soil as Influenced by Nitrogen Management and Cropping Systems

Summary

In this peer-reviewed article published in the Journal of Environmental Quality in 2008, the authors measured the amount of nitrous oxide gas emitted from agricultural soils in Montana. The objective of the study was to determine how crop rotation and nitrogen fertilizer use affect nitrous oxide emissions.

Three different crop rotations were studied over two years. Crop rotations included a wheat-pea rotation and a wheat-wheat rotation, both grown under zero tillage conditions. The crops were grown with three different amounts of nitrogen fertilizer.

Nitrous oxide emissions were minimal while the pea crop was growing. The study also looked at nitrous oxide intensity, which is the amount of nitrous oxide emitted for each kilogram of harvested crop. The nitrous oxide intensity was lower for the wheat-pea rotation than for the wheat-wheat rotation. In other words, the wheat-pea rotation had less nitrous oxide emitted per kilogram of crop harvested. Traditionally, cropping systems in Montana include a fallow year where no crop is produced. This research shows that by replacing the fallow year with a pulse crop, more grain can be produced without a significant increase in nitrous oxide emissions.

Full Document
Dusenbury, M.P., Engel, R.E., Miller, P.R., Lemke, R.L. and Wallander, R. 2008. Nitrous Oxide Emissions from a Northern Great Plains Soil as Influenced by Nitrogen Management and Cropping Systems. Journal of Environmental Quality. 37: 542-550.
https://www.agronomy.org/publications/jeq/abstracts/37/2/542
3.

Strategies for reducing the carbon footprint of field crops for semiarid areas. A review.

Summary

This peer-reviewed article was published in the journal Agronomy and Sustainable Development in 2010. The study compared the carbon footprint of canola, mustard, flax, spring wheat, chickpea, pea, and lentil. In addition, the effect of crop rotation on the carbon footprint of a durum wheat crop was determined.

The carbon footprint was measured as the amount of carbon dioxide emitted per kilogram of grain produced. For each crop, carbon footprints were calculated by adding the greenhouse gas emissions from the decomposition of crop residue, the manufacture and use of fertilizers and pesticides, and other miscellaneous farm operations. The amount of nitrogen contributed by various pulse crops was also estimated.

The production and application of nitrogen fertilizer accounted for up to two-thirds (57% to 65%) of the carbon footprint of each crop. The three pulse crops studied (chickpea, pea, and lentil) had the lowest carbon footprints – an average of two-thirds lower than canola or spring wheat. When durum wheat was grown after a pulse crop, it had a carbon footprint that was 46% lower than if it was grown after spring wheat. Worldwide, it was calculated that pulses produce about 21 million tonnes of nitrogen per year. The article concludes that better farming practices (including the use of pulse crops) can lower the average carbon footprint by 24 to 37%.

Full Document
Gan, Y., Liang, C., Hamel, C., Cutforth, H. and Wang, H. 2011. Strategies for reducing the carbon footprint of field crops for semiarid areas. A review. Agronomy for Sustainable Development. (published online)
http://www.springerlink.com/content/7412412565q18573/
4.

Lowering carbon footprint of durum wheat by diversifying cropping systems.

Summary

This 2011 article in the peer-reviewed Field Crops Research Journal studied the carbon footprint of durum wheat. Durum wheat was grown under zero tillage conditions in nine different crop rotations. Each three-year rotation included two years of pulses, oilseeds, or spring wheat. This was followed by durum wheat in the third year. The pulses studied were lentils, chickpeas, and peas.

The carbon footprint of each rotation was calculated by adding the greenhouse gases from: 1) farming operations including seeding, spraying, and harvesting; 2) the production, transportation, storage, delivery, and application of fertilizers and pesticides; and 3) the decomposition of crop residues.

The study concluded that including pulses in crop rotations can substantially lower the carbon footprint of a subsequent durum wheat crop by up to one-third. When durum was grown after a pulse crop, the carbon footprint was 28% less than when grown after spring wheat. When durum was grown after two consecutive years of pulse crops, the carbon footprint was 34% lower than when durum was grown after two years of cereal crops. The lower carbon footprint was primarily due to the reduction in nitrogen fertilizer requirement when durum was grown after a pulse crop. Pulses can also lower the carbon footprint by diversifying the crop rotation, leading to fewer weed and pest problems.

Full Document
Gan, Y., Liang, C., Wang, X. and McConkey, B. 2011. Lowering carbon footprint of durum wheat by diversifying cropping systems. Field Crops Research. 122: 199–206.
http://www.sciencedirect.com/science/article/pii/S0378429011001158
5.

Agriculture and Greenhouse Gases.

Summary

Henry Janzen is a research scientist with Agriculture and Agri-Food Canada, specializing in agricultural greenhouse gases. In this article, he provides a very readable summary of agricultural greenhouse gases that is intended to generate discussion among farmers, consumers and policy makers. This article appeared in 2008 in the peer-reviewed online journal Prairie Soils and Crops. It provides background information on how agriculture affects greenhouse gases, particularly methane and nitrous oxide. Carbon sequestration and carbon trading are also briefly summarized.

Several perspectives on the problem of agricultural greenhouse gases are discussed. Measuring greenhouse gases has many uncertainties and requires continuous improvement. Because farms are complex ecosystems, changing any one agricultural practice will affect the whole farm ecosystem. Therefore, the “big picture” of farm-level emissions should be the focus of attempts to reduce greenhouse gases. Farms provide important “ecosystem services” (such as food, employment, and wildlife habitat) that may be affected by reducing greenhouse gases. For example, reducing greenhouse gases may have additional benefits such as decreasing soil erosion. Alternately, negative effects such as lower crop yields may occur. Greenhouse gas emissions indicate inefficient use of energy, nutrients, or resources. Reducing greenhouse gases is therefore an opportunity to improve farm efficiency.

Full Document
Janzen, H. Agriculture and Greenhouse Gases.
http://www.prairiesoilsandcrops.ca/articles/Issue-1_Article_1.pdf
6.

Carbon Emissions from Farm Operations

Summary

This article summarizes research on energy use in agriculture and converts the different measurements in each study to the same units (kilograms of carbon). Converting measurements to the same units makes it easier to compare energy use in different crop production systems. Research from around the globe was used; no one specific region was targeted. The article was published in the peer-reviewed journal Environment International in 2004.

The carbon emissions from different farm operations and inputs were calculated. These include tillage, irrigation, seeding, spraying, harvesting, transportation, fertilizers and pesticides. The effect of soil erosion on carbon emissions was also considered. Nitrogen fertilizer was highlighted as a very carbon-intensive input and alternatives such as the use of legumes and pulses are recommended to reduce carbon emissions. The article also discusses some of the ways in which sustainability can be measured and summarizes research that compares energy use in different crop production systems. Many studies have found that reducing the amount of tillage, pesticide and fertilizer use has the most potential to reduce energy use.

Full Document
Lal, R. 2004. Carbon Emissions from Farm Operations. Environment International. 30: 981-990.
http://cirit.osu.edu/clusterone/LASCANET/pdf%20files/Lal_3.pdf
7.

Can Pulse Crops Play a Role in Mitigating Greenhouse Gases from North American Agriculture?

Summary

This article summarized many different experiments investigating the impact of pulse crops on greenhouse gas emissions. It was published in the peer-reviewed Agronomy Journal in 2007. Pulse crops affect the amount of carbon dioxide, nitrous oxide, and methane emitted from the soil they are grown in.

Research shows that crop rotations containing a pulse crop have lower overall greenhouse gas emissions than those that do not include a pulse crop. This is because up to 70% of the non-renewable energy used in Western Canadian cropping systems is due to the use of fertilizers, particularly nitrogen. Pulses supply their own nitrogen, reducing the need for added nitrogen fertilizer. Research on nitrous oxide emissions specifically is limited, but shows that emissions tend to be lower for pulse crops compared to fertilized cereal crops. The more often a pulse crop is grown, the more greenhouse gas emissions are reduced. For example, a 17-year study at Swift Current, SK showed that greenhouse gas emissions were decreased by 31% annually when lentils were included in rotation with spring wheat. A similar study at Indian Head, SK showed an 18% reduction in yearly greenhouse gas emissions when peas were included in rotation with spring wheat, winter wheat, and flax.

Full Document
Lemke, R.L., Zhong, Z., Campbell, C.A. and Zentner, R. 2007. Can Pulse Crops Play a Role in Mitigating Greenhouse Gases from North American Agriculture? Agronomy Journal. 99: 1719–1725.
https://www.crops.org/publications/aj/pdfs/99/6/1719
8.

Nitrous Oxide Emissions and Prairie Agriculture

Summary

This brief article was published in 2008 in the peer-reviewed online journal Prairie Soils and Crops. It provides background information on the properties and sources of nitrous oxide, which is a potent greenhouse gas that also causes destruction of the ozone layer. Agriculture is the largest source of human-created nitrous oxide emissions. Methods of reducing nitrous oxide emissions in agriculture are discussed, as are areas where more research is needed.

In this article, the chemical processes that cause nitrous oxide emissions are described in a straightforward way. The greatest nitrous oxide emissions occur when high soil moisture coincides with high levels of soil nitrogen (in the form of nitrate). This suggests that there are opportunities to reduce nitrous oxide emissions with better farm management. Any practice that uses nitrogen more efficiently will reduce nitrous oxide emissions because it reduces excess nitrogen in the soil. Pulse crops can reduce nitrous oxide emissions because they don’t require nitrogen fertilizer. Innovations in fertilizer technology that may reduce nitrous oxide emissions are also described.

Nitrous oxide emissions are extremely variable over space and time, making measurements challenging. More research is needed to understand this variability so that the impact of different management practices can be understood.

Full Document
Lemke, R. and Farrell, R. Nitrous Oxide Emissions and Prairie Agriculture.

http://www.prairiesoilsandcrops.ca/articles/Issue-1_Article_2.pdf
9.

Estimation of N2O emissions from agricultural soils in Canada. II. 1990-2005 inventory

Summary

This peer-reviewed article, published in the Canadian Journal of Soil Science in 2008, estimates nitrous oxide emissions from Canadian agricultural land from 1990 to 2005. The study was done because international agreements and negotiations on climate change require that countries determine their national production of greenhouse gases.

Approximately two-thirds of nitrous oxide emissions from agriculture in Canada were from agricultural soil (68%), with the remainder from animal waste management and the indirect loss of nitrogen from land (e.g. through leaching or erosion). Of the emissions from agricultural soils, application of nitrogen fertilizers was the largest source (35%). Other important sources were crop residues, grazing animals, and manure applied to soil.

Full Document
Rochette, P., Worth, D.E., Huffman, E.C., Brierley, J.A., McConkey, B.G., Yang, J., Hutchinson, J.J., Desjardins, R.L., Lemke, R. and Gameda, S. 2008. Estimation of N2O emissions from agricultural soils in Canada. II. 1990-2005 inventory. Canadian Journal of Soil Science. 88: 655-669.
http://pubs.aic.ca/doi/pdf/10.4141/CJSS07026
10.

In Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change

Summary

This document is a peer-reviewed chapter from a book written for the Intergovernmental Panel on Climate Change. The chapter describes the proportion of global anthropogenic greenhouse gases that are emitted by agriculture, and how greenhouse gas emissions from agriculture have risen and are projected to continue rising in various regions of the world.

 Agricultural greenhouse gas mitigation options are cost competitive with non-agricultural options in achieving long term greenhouse gas policy goals. Different mitigation options are presented for both crop and livestock production, including the use of rotations with legume crops to reduce the reliance of cropping systems on external nitrogen inputs.

Full Document
Smith, P., Martino, D., Z. Cai, D. Gwary, H. Janzen, P. Kumar, B. McCarl, S. Ogle, F. O’Mara, C. Rice, B. Scholes, O. Sirotenko, 2007: Agriculture. In Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, L.A. Meyer (eds)], Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
http://www.ipcc.ch/pdf/assessment-report/ar4/wg3/ar4-wg3-chapter8.pdf
11.

Review of greenhouse gas emissions from crop production systems and fertilizer management effects

Summary

This detailed article, published in 2009 in the peer-reviewed journal Agriculture, Ecosystems and Environment, reviews current research on the effect of nitrogen fertilizer use on greenhouse gases.

Greenhouse gas emissions from agriculture, especially due to fertilizer use, are described and compared with emissions from other sources. The ways that specific farming practices affect greenhouse gas emissions are then discussed. In particular, the type, amount, timing, and placement of nitrogen fertilizer are considered. Farming practices that reduce greenhouse gas emissions without reducing crop yields are suggested.

One section explores nitrous oxide emissions from legume crops (which include pulse crops). Nitrous oxide emissions from legume crops are low while the crop is actively growing. However, there is uncertainty about whether or not legumes result in higher nitrous oxide emissions than other crops when the crop residues decompose. Another article in this science library (Zhong et al., 2011) explores this issue further and provides evidence that pulse residues do not increase nitrous oxide emissions.

Full Document
Snyder, C.S., Bruulsema, T.W., Jensen, T.L. and Fixen, P.E. 2009. Review of greenhouse gas emissions from crop production systems and fertilizer management effects. Agriculture, Ecosystems and Environment. 133: 247-266.
http://www.sciencedirect.com/science/article/pii/S0167880909001297
12.

Nitrous oxide emissions from grain legumes as affected by wetting/drying cycles and crop residues

Summary

This article, published in 2011 in the peer-reviewed journal Biology and Fertility of Soils, studied the effect of pulses on nitrous oxide emissions. Agriculture is a major source of nitrous oxide, which is a potent greenhouse gas with about 300 times the global warming effect of carbon dioxide. Scientists have been concerned that pulse crops could cause an increase in nitrous oxide emissions when the nitrogen-rich crop residues of pulses decompose.

The experiment included two different pulses (peas and lentils) that were grown under three different soil moisture conditions in Saskatchewan. The peas and lentils were either inoculated with symbiotic rhizobia microbes to enhance nitrogen fixation, or fertilized with nitrogen fertilizer. Results were compared to spring wheat that was also grown under three different soil moisture conditions.

The importance of this study is that it found that growing pulses did not increase nitrous oxide emissions when compared to spring wheat production. In contrast, the application of nitrogen fertilizer had a greater effect on increasing nitrous oxide emissions. In addition, soil nitrous oxide emissions were not higher when pulse residues were incorporated into soil.

Full Document
Zhong, Z., Nelson, L.M. and Lemke, R.L. 2011. Nitrous oxide emissions from grain legumes as affected by wetting/drying cycles and crop residues. Biology and Fertility of Soils. 47: 687–699.
http://www.springerlink.com/content/y6301447q0343q5p/

 

Pulse Impact on Cropping Systems / Soil and Water Impact

1.

Adaptation of alternative pulse and oilseed crops to the semiarid Canadian Prairie: Seed yield and water use efficiency

Summary

This 2008 research paper, published in the peer-reviewed Canadian Journal of Plant Science, studied water use by pulses and other crops. The ability of crops to adapt to different water conditions is important because moisture for crop growth is frequently in short supply.

The study included three pulses (chickpea, lentil, and pea) as well as canola, mustard, and wheat. Three different moisture conditions were studied: drought, normal rainfall, and irrigation. The study took place in Saskatchewan over four years.

Of the crops studied, wheat and pea had the highest yields and highest water use efficiency, while pea used the least amount of water. Chickpea and lentil produced good yields even when water was limited. Under severe drought conditions, where some crops did not produce any appreciable yields, chickpea and lentil were able to maintain at least some yields. The study concluded that pulse crops are well-suited to low moisture conditions.

Full Document
Angadi, S.V., McConkey, B.G., Cutforth, H.W., Miller, P.R., Ulrich, D., Selles, F., Volkmar, K.M., Entz, M.H. and Brandt, S.A. 2008. Adaptation of alternative pulse and oilseed crops to the semiarid Canadian Prairie: Seed yield and water use efficiency. Canadian Journal of Plant Science. 88: 425-438.
http://pubs.aic.ca/doi/pdf/10.4141/CJPS07078
2.

Comparing plant water relations for wheat with alternative pulse and oilseed crops grown in the semiarid Canadian prairie

Summary

Published in the Canadian Journal of Plant Science in 2009, this peer-reviewed study examines the drought tolerance of different crops. Drought tolerance is important because precipitation in the Canadian Prairies can be low and unpredictable.

The crops studied were pea, chickpea, canola, mustard and wheat. Each crop was grown under three different water conditions: drought, normal rainfall, and irrigation. It was conducted in Saskatchewan during a two year period. The paper first provides some background about how individual plant cells are affected by water stress before examining each crop’s response to drought in detail.

The study found that pea and chickpea had the greatest ability to withstand water stress, followed by wheat and then the two oilseed crops. This research shows the advantage of growing pulses in drought-prone areas.

Full Document
Cutforth, H.W., Angadi, S.V., McConkey, B.G., Entz, M.H., Ulrich, D., Volkmar, K.M., Miller, P.R. and Brandt, S.A. 2009. Comparing plant water relations for wheat with alternative pulse and oilseed crops grown in the semiarid Canadian prairie. Canadian Journal of Plant Science. 89: 826-835.
http://pubs.aic.ca/doi/pdf/10.4141/CJPS08138
3.

Conserving soil and water with sustainable cropping systems: research in the semiarid Canadian Prairies

Summary

This article was prepared for the 2002 International Soil Conservation Organization conference held in Beijing. It was written by several researchers from Agriculture and AgriFood Canada. The paper summarizes two research projects conducted in Saskatchewan that looked at the effect of pulses on water use efficiency and soil quality.

One of the studies was long-term (more than 30 years) and included continuous wheat, wheat/fallow, or wheat/lentil rotations. The other study was short-term (two years) and included oilseeds, wheat, and pulses (lentil, pea, and chickpea).

The two studies found that using pulses reduced the leaching of nitrates, which minimizes the possibility of groundwater pollution. Including pulses also resulted in better soil quality than continuous wheat. In particular, pulses increased soil organic matter and promoted larger, more diverse populations of soil microbes. Rotations that included pulses required less nitrogen fertilizer, particularly when pea was grown. Pulses, especially pea and lentil, also tended to conserve water for the following crop. Overall, rotations that included pulses improved water and nutrient use efficiency, increased yields and raised protein concentrations.

Full Document
Gan, Y.T., Zentner, R.P., Campbell, C.A., Biederbeck, V.O., Selles, F. and Lemke, R. 2002. Conserving soil and water with sustainable cropping systems: research in the semiarid Canadian Prairies. Presentation to 12th ISCO Conference, Beijing, China.
http://pulsecanada.com/media/gan-et-al.-2002-conserving-soil-and-water-with-sustainable-cropping-systems-research-in-the-semiarid-cdn-prairies.pdf
4.

Influence of Diverse Cropping Sequences on Durum Wheat Yield and Protein in the Semiarid Northern Great Plains

Summary

The objective of this study was to determine if durum wheat yield and quality were affected by the crops grown in the previous two years. It was published in the peer-reviewed Agronomy Journal in 2009.

Three pulses (pea, chickpea, and lentil) and two oilseeds (mustard and canola) were grown prior to durum wheat. The protein concentration and grain yield of the durum wheat crop were measured. This study was conducted over a four-year period at two locations in Saskatchewan.

Results showed that yields and protein content increased when durum was grown after either pulses or oilseeds, but were highest after pulses. Durum yields were increased by 7% and protein was increased by 11% when durum was grown after a pulse rather than spring wheat. Approximately one-quarter of the yield increase was due to increased nitrogen and water remaining after the pulse crop was harvested. This study concluded that both pulses and oilseeds provide significant benefits when grown in rotation with durum wheat.

Full Document
Gan, Y.T., Miller, P.R., McConkey, B.G., Zentner, R.P., Stevenson, F.C. and McDonald C.L. 2003. Influence of Diverse Cropping Sequences on Durum Wheat Yield and Protein in the Semiarid Northern Great Plains. Agronomy Journal. 95: 245-252.
https://www.agronomy.org/publications/aj/abstracts/95/2/245
5.

Water use and distribution profile under pulse and oilseed crops in semiarid northern high latitude areas

Summary

This peer-reviewed article was published in the journal Agricultural Water Management in 2008. The purpose of the research was to describe in detail how pulse and oilseed crops use water. Water stress can significantly restrict crop production, so it is important that crops can thrive even in low and unpredictable moisture conditions.

The study included pea, lentil, chickpea, canola, and mustard. It measured the amount of water each crop used at different soil depths. Each crop was grown under two different moisture conditions: normal rainfall and irrigation. It was conducted in Saskatchewan over a two-year period.

Results showed that pulse crops tended to use water more slowly than oilseeds or wheat. Pulses also used less water from deep in the soil. This unused water would benefit a deep-rooted crop grown after a pulse. All three pulses studied, but particularly lentil and chickpea, were well-adapted to drought conditions. These results are useful for planning crop rotations to use water resources more efficiently.

Full Document
Gan, Y.T., Campbell, C.A., Liu, L., Basnyat, P. and McDonald, C.L. 2009. Water use and distribution profile under pulse and oilseed crops in semiarid northern high latitude areas. Agricultural Water Management. 96: 337-348.
http://www.sciencedirect.com/science/article/pii/S037837740002047
6.

Introduction to "Pulse Crop Ecology in North America: Impacts on Environment, Nitrogen Cycle, Soil Biology, Pulse Adaptation, and Human Nutrition"

Summary

Published in Agronomy Journal in 2007, this is a short article that provides a broad overview of the benefits of pulses as well as key directions for future research. It is the introduction to a symposium about pulse crops held at the annual conference of the American societies for agronomy, crop science, and soil science.

To begin with, the current status of land seeded to pulses in North America is reviewed. In the period from 1991 to 2006, the area seeded to pulses increased more than seven times. The nutritional benefits of pulses are then discussed. In addition to their high protein and fibre contents, pulses also contain compounds called phytochemicals that promote good health. Next, the environmental impact of pulses in terms of reducing greenhouse gas emissions is considered. The article also covers the positive impact pulses have on beneficial soil microbes that enhance plant growth. Finally, the ability of pulses to adapt to changing climate conditions is examined. Overall, pulses are playing an increasingly important role in North American agriculture.

Full Document
Johnston, A.M., Clayton, G.W. and Miller, P.R. 2007. Introduction to "Pulse Crop Ecology in North America: Impacts on Environment, Nitrogen Cycle, Soil Biology, Pulse Adaptation, and Human Nutrition". Agronomy Journal. 99: 1682-1683.
http://wwwtest.soils.org/publications/aj/articles/99/6/1682
7.

Grain Legumes in Northern Great Plains: Impacts on Selected Biological Soil Processes

Summary

Published in Agronomy Journal in 2007, this peer-reviewed article summarizes how pulses affect soil biology and identifies some areas for future research. The pulses included in this summary were pea, lentil, bean, and chickpea.

Soil biology is important because microbes in the soil play a role in many of the benefits that pulses provide. Most importantly, soil microbes are responsible for the symbiotic relationship that helps pulses produce nitrogen. Pulses also release substances that affect soil microbes differently than other crops do. Pulses produce different types of amino acids and organic acids that can make soil nutrients more available to other crops. They may also increase the amount of mycorrhizae, which are a type of soil fungi that improve the uptake of water and nutrients by crops. Another type of microbe increased by pulses is endophytic rhizobia. These beneficial microbes can stimulate growth and enhance the resistance of crops to stresses such as diseases and drought.

The authors conclude that in general, pulses have a positive effect on agriculture because they add and recycle nitrogen, improve nutrient uptake, reduce greenhouse gas emissions, and decrease pest problems.

Full Document
Lupwayi, N.Z. and Kennedy, A.C. 2007. Grain Legumes in Northern Great Plains: Impacts on Selected Biological Soil Processes. Agronomy Journal. 99: 1700-1709.
http://wwwtest.agronomy.org/publications/aj/abstracts/99/6/1700
8.

Soil microbial diversity and community structure under wheat as influenced by tillage and crop rotation

Summary

This study was published in the peer-reviewed journal, Soil Biology and Biochemistry in 1998. The study, based in northern Alberta, Canada, investigates the impact of legume-based crop rotations (field peas and red clover) and tillage management on the diversity of soil bacteria in a wheat crop.

Soil microbial diversity is important to sustainable agriculture because microbes mediate many processes that support agricultural production, including the cycling of plant nutrients. This study showed that soil microbial diversity was significantly higher when wheat was grown after field peas, compared to when wheat was grown after wheat. Tillage management also affected soil microbial diversity, with conservation (zero) tillage systems having significantly higher soil microbial diversity than conventional tillage systems.

The authors conclude that these results indicate that legume-based crop rotations and conservation tillage support diversity of soil microbial communities and may improve the sustainability of agricultural ecosystems.

Full Document
Lupwayi, N.Z., Rice, W.A. and Clayton, G.W. 1998. Soil microbial diversity and community structure under wheat as influenced by tillage and crop rotation. Soil Biology and Biochemistry. 30: 1733-1741.
http://www.sciencedirect.com/science/article/pii/S003807179800025X
9.

Pulse Crop Adaptation in the Northern Great Plains

Summary

Miller and colleagues reviewed the current research on the production of peas, lentils, beans, soybeans, and chickpeas in western Canada and the northern USA. Published in Agronomy Journal in 2002, this article summarizes how pulse crops affect environmental sustainability in terms of crop yields and efficiency of water use. Key areas for further research are also outlined.

Overall, research shows that pulse crops consistently provide a nitrogen benefit to wheat that is grown after a pulse. This nitrogen benefit is demonstrated by higher wheat grain yields and higher wheat protein content (nitrogen is a major building block of protein). This is important because nitrogen supplied by a pulse crop reduces the need for nitrogen fertilizer, an input that is energy-intensive to produce and is responsible for a large portion of the greenhouse gas emissions in agriculture.

Peas, lentils, and chickpeas were specifically highlighted as crops that efficiently use water. Research suggests that these three pulse crops respond to drought conditions better than spring wheat. By using less water, pulses conserve water for use by subsequent crops. This is particularly important because water is a major limiting factor in growing crops in the northern Great Plains.

Full Document
Miller, P.R., McConkey, B.G., Clayton, G.W., Brandt, S.A., Staricka, J.A., Johnston, A.M., Lafond, G.P., Schatz, B.G., Baltensperger, D.D. and Neill, K.E. 2002. Pulse Crop Adaptation in the Northern Great Plains. Agronomy Journal. 94: 261-272.
https://www.agronomy.org/publications/aj/abstracts/94/2/261
10.

Pulse Crops for the Northern Great Plains: II. Cropping Sequence Effects on Cereal, Oilseed, and Pulse Crops

Summary

This peer-reviewed article was published in Agronomy Journal in 2003. The objective of this study was to compare the effect of three pulses (chickpea, lentil, and pea) on the next crop (wheat, mustard, canola, pea, or lentil). This study is unique because it considered the effect of soil texture (clay versus loam soil) on the crop rotation. The study was conducted in Saskatchewan during a three year period.

The study found that soil texture was important because the benefits of pulse crops were more consistent for the clay soil than the loam soil. Growing pea or lentil before wheat, mustard, or canola resulted in better yields, probably because pulses left more water in the soil for the next crop. In addition, pulses had better yields when grown after wheat than when grown after another pulse crop. This research demonstrates that using diverse crop types is beneficial to all the crops in the rotation.

Full Document
Miller, P.R., Gan, Y., McConkey, B.G. and McDonald, C.L. 2003. Pulse Crops for the Northern Great Plains: II. Cropping Sequence Effects on Cereal, Oilseed, and Pulse Crops. Agronomy Journal. 95: 980-986.
https://www.agronomy.org/publications/aj/abstracts/95/4/980
11.

Rotational yield and apparent N benefits of grain legumes in southern Manitoba

Summary

This study was published in the peer-reviewed Canadian Journal of Plant Science in 2004. The objective of the research was to compare the effect of four different pulse crops and a flax crop on the yield and nitrogen content of the next crop (spring wheat). The pulse crops studied were pea, chickpea, bean, and soybean. The research was done at two different locations in southern Manitoba over a three year period.

Of the crops studied, pea consistently provided the most benefit to the wheat crop. The other pulse crops had varying benefits depending on the location and their adaptation to the local growing conditions. For example, chickpea showed the most potential to provide benefits in dry conditions.

Full Document
Przednowek, D.W.A., Entz, M.H., Irvine, H., Flaten, D.N. and Thiessen Martens, J.R. 2004. Rotational yield and apparent N benefits of grain legumes in southern Manitoba. Canadian Journal of Soil Science. 84: 1093-1096.
http://pubs.aic.ca/doi/pdf/10.4141/P04-032
12.

How can increased use of biological N2 fixation in agriculture benefit the environment?

Summary

This peer-reviewed article summarizes the benefits that legumes and pulses provide. The article discusses nitrogen production but focuses in particular on the other effects legumes have on the environment. Examples include pulses as well as tree and pasture legumes grown around the world. The article was published in the journal Plant and Soil in 2003.

A major benefit of pulses is to reduce the need for nitrogen fertilizer and the energy used in its manufacture, transportation, and application. But pulses have other effects, too. Pulses and other legumes can increase the acidity of the soil. In many cases, this is beneficial because acidity allows nutrients such as phosphorus to be more available for plant growth. In other cases where the soil is already very acidic, increased acidity could be harmful, so the use of legumes may need to be combined with methods to reduce soil acidity. Legumes can also reduce the loss of nitrogen from the soil. This is important because lost nitrogen can end up as a water pollutant or greenhouse gas. Pulses also stimulate the activity of beneficial soil organisms such as earthworms, and have a positive impact on soil structure. Finally, using pulses in crop rotations can decrease pest levels, resulting in reduced need for pesticides.

Full Document
Steen Jensen, E. and Hauggaard-Nielsen, H. 2003. How can increased use of biological N2 fixation in agriculture benefit the environment? Plant and Soil. 252: 177-186.
http://www.springerlink.com/content/ur2175554761530h/
13.

The nitrogen and non-nitrogen rotation benefits of pea to succeeding crops

Summary

This peer-reviewed article, published in 1996 in the Canadian Journal of Plant Science, studied the benefits of growing a pea crop prior to spring wheat.

A special form of nitrogen, called nitrogen-15, was used to track the amount of nitrogen produced by the pea crop and its use by the following wheat crop. In addition to providing nitrogen, there are other ways pulses can benefit subsequent crops: reducing diseases and weeds, increasing the availability of other nutrients such as phosphorus, improving the soil structure, and releasing growth-promoting substances. The study also looked at these “non-nitrogen benefits” for the next crop. The study was conducted at three locations in Saskatchewan over a three year period.

This study found that when pea was grown before wheat, the wheat yield was 43% greater than if wheat was grown after another wheat crop. The yield benefit was consistently observed at all three locations. Of this yield increase, 8% was due to the nitrogen provided by the pea crop. The remaining 92% of the benefit from the pea crop was due to other factors, especially the reduction of wheat root diseases. This study demonstrates that pulses provide significant benefits that go beyond their nitrogen-producing ability.

Full Document
Stevenson, F.C. and van Kessel, C. 1996. The nitrogen and non-nitrogen rotation benefits of pea to succeeding crops. Canadian Journal of Soil Science. 76: 735-745.
http://pubs.aic.ca/doi/pdf/10.4141/cjps96-126
14.

Crop rotations for the 21st century.

Summary

This 1994 paper reviews the history of crop rotations, including the use of pulse crops and other legumes.  It focuses primarily on US agriculture and discusses agronomic, policy and economic issues related to crop rotation. It was published in the peer-reviewed journal Advances in Agronomy.  
The paper discusses how crop rotation promotes sustainable agriculture by improving soil fertility, reducing pest and weed levels, promoting efficient water use, and increasing crop yields. For thousands of years, legumes such as pulses were used to provide nitrogen to maintain soil fertility.  Farmers began to abandon crop rotation after pesticides and nitrogen fertilizer became available, as many believed that they could replace the benefits of crop rotations. More recently, the general consensus among agricultural scientists is that no amount of fertilizer or pesticide can fully compensate for the benefits of crop rotation. Characteristics of successful crop rotations are also discussed. For example, when legumes are used in crop rotations, it is important to choose a subsequent crop that effectively uses the leftover nitrogen.
In the future, using legumes in crop rotations may encourage the production of energy crops. The need for energy-intensive nitrogen fertilizer is the major limitation in using crops as an energy source; however, using nitrogen-producing legumes in rotation with energy crops could solve this problem. Future crop rotation research is needed to more fully explain the advantages of crop rotation, as this may make farmers more likely to use this practice.



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