The Sustainability Benefits of Pulses
Low Carbon Footprint
The production and use of nitrogen fertilizers are a significant contributor to the overall carbon footprint of agriculture and food production. Pulses have a naturally lower carbon footprint than most foods because they require little to no nitrogen fertilizer to grow. Pulses have a special relationship with certain soil bacteria that convert nitrogen from the air into a form that is usable to the growing pulse crop. This process is known as symbiotic nitrogen fixation.
Soil Health and Crop Systems
Pulses produce a number of different compounds that feed soil microbes and benefit soil health. A healthy and diverse microbial community is able to decompose and cycle nutrients more efficiently, feeding crops naturally as they grow. In addition, a large, diverse population of soil microorganisms acts to ‘crowd out’ disease-causing bacteria and fungi, making for healthier plants. Growing pulse crops in a rotation with other crops enables the soil environment to support these large, diverse populations of soil microorganisms.
Pulses are a protein source with a very low water footprint. Pulses such as peas, lentils and chickpeas are well-adapted to semi-arid conditions and can tolerate drought stress. Pulse crops like peas and lentils also use water in a different way than other crops grown in rotation, extracting water from a shallower depth, leaving more water deep in the soil for the following year’s cereal or oilseed crop.
Canadian Pulses: A World Leader
Negative Carbon Balance
In addition to the general sustainability benefits of pulses, the production practices used by Canadian growers help to sequester carbon into the soil. Canadian farmers have adopted practices such as minimum tillage and reducing fallowing, which are practices that have been proven to sequester large amounts of atmospheric carbon into soils. This sequestration of soil carbon negates the carbon emissions of producing a pulse crop. creating a carbon neutral or even carbon negative crop. In effect, these practices make Canadian pulses like peas and lentils effectively carbon neutral or negative1.
Including Canadian pulses in crop rotations also confers sustainability benefits for the crops grown after. Crops like wheat and barley produce higher yields and have higher protein when grown after pulses. This is due to the soil fertility, water and soil microbial benefits of pulse crops which also benefit following crops. These benefits also reduce the carbon emissions of following crops due to a reduced need for fertilizer. One study has estimated that including pulses in a rotation with Canadian wheat contributed 1.3 MT of carbon emission savings, approximately 2% of the entire carbon footprint of Canadian agriculture2.
Life Cycle Assessment
Canadian pulses have a role to play in improving the environmental impact of foods and diets. That is why Pulse Canada has undertaken work to develop Life Cycle Assessments (LCAs) for major Canadian pulse crops. We will be sharing the findings of these LCAs as they are completed.
Industry, governments and academics are currently using software to conduct Life Cycle Assessments of agricultural products, foods, and diets from a national and global perspective. Life Cycle Assessments require databases which contain all the necessary information related to the production of food products.
As interest is increasing in plant-based diets and foods, there is also an increased need to measure the environmental impacts of these diets and foods. In response, data is being collected on Canadian pulses and is being published in global Life Cycle Databases, such as EcoInvent.
Improving The Sustainability of Food Products
Incorporating Canadian pulses into food products, whether plant or animal-based, can improve the environmental footprint including carbon emissions, water use and land use.
In addition to improving the nutritional profile of staple cereal-based foods, incorporating Canadian pulse ingredients, such as pea or lentil flour, can significantly reduce the carbon footprint of the final product3.
Pulses are being used in meat applications in a number of ways, but an emerging trend is blending plant and animal protein in a single product. The environmental footprint of 100% beef burgers (both U.S. and Canadian origin) was compared to a blended burger of 67% beef and 33% Canadian lentils. The blended burger had a significantly improved footprint including lower carbon emissions, water use, land use and improved biodiversity4.
1. Canadian Roundtable for Sustainable Crops.
2. MacWilliam, S. et al. 2018. A meta-analysis approach to examining the greenhouse gas implications of including dry peas (Pisum sativum L.) and lentils (Lens culinaris M.) in crop rotations in western Canada. Agricultural Systems, 166:101-110. Doi: https://doi.org/10.1016/j.agsy....
3. Chaduhary, A. et al. Unpublished data.
4. Chaudhary, A. & Tremorin, D. 2020. Nutritional and Environmental Sustainability of Lentil Reformulated Beef Burger. Sustainability, 12:6712. Doi: https://doi.org/10.3390/su1217...