The Multiple Benefits of Being Sustainable - PulseResearch
April 24, 2017
Pulses make environmental, economic, and long-term sense for growers
The term sustainability is thrown around a lot these days.
But what exactly does it mean in relation to pulse crops, and why is this concept increasingly important to pulse growers in Saskatchewan and to the pulse industry in general?
Saskatchewan Pulse Growers (SPG) aims to answer some of these questions through research around pulses and sustainability, one of the major focuses of the organization’s overall research program.
The idea of sustainability is multi-faceted, says SPG Director Lee Moats.
“Sustainability means a lot of things to a lot of people — there is quite a broad interpretation of the term,” says Moats, who also operates a zero-till farm in the Riceton area with his wife Laurie.
“For a lot of us I think it has a lot to do with economics as much as with environment, but of course the two go hand-in-hand.”
A 2012 Agriculture and Agri-Food Canada report supports this definition, relating sustainability principles for agriculture to “stewardship of land, air, and water, and other natural resources as well as quality of life and long term profitability for food producers and rural communities.”
On the environmental side of sustainability is the idea that pulse crops contribute to improved soil health, overall environmental footprint, and long-term sustainability, facts which have been supported by research. Economically speaking, farming sustainably improves yields, reduces input costs, creates longterm financial stability, and there are economic gains with crops following pulses in rotation.
Sustainability is not only attractive to growers in terms of opportunities for increased yields and lower input costs, but also for end-use markets, as there is growing consumer demand for sustainably sourced food products and sustainable metrics for food production. This consumer demand is a trend which is growing consistently, Moats says.
“When I came on the SPG Board, really there was only one company talking to us about sustainability and they were more interested in oats than in pulses,” he says. “But in the past five years, sustainability has become a corporate word and many of the big companies are interested in this idea — it has become commonplace.”
Research backs this claim up. A 2014 Nielsen survey showed that 55 per cent of global consumers reported being inclined to pay more for products and services from companies that were committed to social and environmental sustainability. By the next year that number had jumped to 72 per cent. In the past decade, many of the world’s leading companies have adopted programs and marketing campaigns to demonstrate their commitment to sustainable practices, including PepsiCo, Starbucks, Molson Coors Brewing Co., Kellogg Co., Loblaws, Canadian Tire, Rogers Communications, Telus, Air Canada, and the list goes on.
Since the areas of grower economics and consumer demand clearly hold great potential for the growth of the Saskatchewan pulse industry, SPG has made it a priority to generate viable proof of the type of information these communities are looking for, Moats says.
“If you are going to talk about sustainability, you need to have some level of confidence in what you are saying. We have many features to do with pulse crops that have great sustainability benefits to our cropping systems but the question is, what are the real scientific proofs that relate to that?”
“That is critically important — consumers that are interested in sustainability want to know the real truth, real facts.”
Understanding the Pulse Contribution to Sustainability
Putting some scientific metrics around pulses’ contribution to sustainability is a fundamental component of SPG’s research strategy, and the organization continues to fund research projects that aim to do just that.
One of these projects, led by Dr. Yantai Gan, a Research Scientist with Agriculture and Agri-Food Canada, has already derived several important conclusions about how various crop rotations affect soil health, environmental footprints, and long-term sustainability in Saskatchewan.
In terms of soil health, the research so far shows that agronomic practices influence the soil’s biological diversity and functionality, with positive implications for plant growth.
“Pulse crops positively influence soil microbial community structure and such effects are carried over to affect the productivity of subsequent crops,” Dr. Gan says. “Plant roots modify soil microbial environments, leading to the crop rotational effect. The plant genotype also influences the root fungal community structure.”
Understanding the negative repercussions on sustainability is also important so that we can work towards improvements. Dr. Gan’s research also showed negative repercussions for plant growth as well. For example, he found that foliar fungicides can negatively affect the composition of rhizobacterial communities. He also found that raising nitrogen levels can increase the risk of nitrous oxide emissions from cropping.
But all this information contributed to an important understanding of the mechanisms responsible for the crop rotational effect.
“This discovery provides a scientific basis that soil health can be improved by manipulating rhizospheric traits of host plants and that the crop rotational effect can be enhanced by modifying microbial communities through use of beneficial agronomic practices.”
In terms of environmental footprint, the research showed that rotations including lentils, for example, have proven benefits as the higher nitrogen concentrations in lentil residues provided greater nitrogen benefits to subsequent crops.
“It is clear that the use of grain legumes to replace the summerfallow phase of the rotation is one of the key components for obtaining a reduced or negative carbon footprint in wheat cropping,” Dr. Gan says.
In order to measure sustainability, Dr. Gan and his team conducted a three-year cropping sequence study which was repeated for five cycles in Saskatchewan. They found that diversifying cropping systems with pulse crops can enhance soil water conservation, improve soil nitrogen availability, and increase system productivity.
Overall, the research contributed several takeaways to the greater discussion of pulses and sustainability, which translates to benefits for the Saskatchewan pulse industry.
“Pulses deliver several unique services to global trade and society as a whole,” Dr. Gan says.
“With the increased global demand for plant-based protein sources and with the desire of diversifying human diets, Saskatchewan pulses are well positioned for global trade. Also, with the Canadian government’s current science agenda on promoting research to combat climate change, nitrogen-fixing pulses can play an important role in reducing both on-farm direct emissions and indirect emissions associated with the inorganic nitrogen fertilizer supply chain.”
In order to further these results, Dr. Gan’s research over the next five years will aim to address the need to increase crop yield at the system level while minimizing negative environmental impacts of crop production.
“A systems approach allows for the integration of various improved agronomic practices in a package that growers can adopt to increase crop yield and reduce crop inputs or improve the efficiency per unit of input, while enhancing economic returns and minimizing environmental footprints.”
Along similar lines to Dr. Gan’s research, ongoing research by Dr. Richard Farrell and his colleagues compares nitrous oxide emissions from different pulses (including peas, lentils, chickpeas, and faba beans), oilseeds (including canola and flax), and wheat crops, alone, and in rotation. The research is also looking at the longer-term benefits of growing pulses.
“Everyone knows that when you grow pulses you do not put much fertilizer on so you get lower emissions,” says Dr. Farrell, Associate Professor in the Department of Soil Science, at the University of Saskatchewan’s (U of S) College of Agriculture and Bioresources. “This research is more about trying to demonstrate that pulse crops have a benefit that goes beyond just the year in which you grow them. What we are trying to show is that the pulse residues do not really contribute a lot to the next year’s emissions either.”
The research also aims to address the fact that the average emission factor in Canada for nitrogen added to soils is one per cent, regardless of the source of nitrogen. Research specific to the Western Canadian prairies indicates that for this region the number is closer to 0.4 to 0.6 per cent, but still does not take nitrogen source into account. When research wraps up in 2017, Dr. Farrell hopes to be able to make a strong case for lowering the emission factor for crop residues, especially for pulse crops.
“We are hoping to be able to come up with a better emission estimate,” he says. “What we would like to be able to show is that the amount going into the atmosphere is actually much lower than that one percent — those inventory numbers are much too high already.”
Since about 17 per cent of all agriculturebased emissions are currently attributed to the decomposition of crop residues, his hope is that this research will impact the greenhouse gas inventory for Canada, potentially decreasing the numbers associated with pulse crops.
“Everyone already suspects that but our data will prove it,” he says.
More SPG-funded research on the topic of pulse sustainability is being carried out by Dr. Diane Knight, a Saskatchewan Ministry of Agriculture Strategic Research Chair with the U of S’s Department of Soil Science. Along with her colleagues, Dr. Knight is looking at cropping sequence effects on nitrogenfixation and carbon and nitrogen inputs of peas, lentils, and chickpeas.
To carry this out, the team conducted studies in both the field and in the greenhouse to measure and compare the amounts of carbon and nitrogen in above- and below-ground residues added by different pulse crops, including chickpeas, peas, and lentils in different rotation sequences with wheat, and canola or mustard.
What they have learned so far is that cropping sequence has a large effect on productivity and biological nitrogen fixation (BNF).
“Not surprisingly, each of the pulse crops performed least well when grown in a continuous rotation compared to diverse rotations,” Dr. Knight says. “Growing lentils and chickpeas after canola or mustard in rotation negatively affected BNF and productivity in both pulse crops compared to when the pulses were grown immediately after wheat. Therefore at least in the Brown soil zone, it is recommended that the pulse crops not be grown immediately after a brassica crop.”
In a different study conducted in the Dark Brown soil zone, the pulse crops were not negatively affected by being grown immediately after canola.
Dr. Knight has also learned that first-year crops in a three-year rotation influenced productivity and BNF.
“In the third year of a rotation sequence where chickpeas or lentils were grown alternately with wheat, the pulse crops were up to 40 per cent more productive and fixed more nitrogen than chickpeas and lentils in rotations where peas were grown as the first crop in rotation, followed by wheat and then chickpeas or lentils,” she says. “We suspect that, at least in the Brown soil zone, growing the same pulse crop repeatedly in rotation, separated by wheat, might serve to encourage microflora populations that are optimal for that crop.”
While continuously cropping pulse crops is neither recommended nor practiced by growers, increasing diversity beyond growing a pulse crop every second year did not necessarily improve nitrogen-fixation and productivity, Dr. Knight says.
“In the Brown soil zone, growing a pulse crop alternately with wheat should maximize the benefit of the pulse crop.”
Dr. Knight expects the overall outcome of her research, which is halfway complete, will provide concrete information on optimal rotation sequences in the different soils zones.
“The overall goal of this and related research is to find the best fit for the different pulse crop species in different regions of the province. Reducing nitrogen fertilizer usage is an economic and environmental goal.”
Other SPG-funded research in the area of sustainability has focused on analyzing the lifecycle and socio-economic effect of pulse crop production and pulse grain use in Western Canada, and examining the soil carbon and nitrogen balance with lentil crops.
For a list of research related to sustainability, download the magazine.
The Importance of Sustainability for Growers
Beyond the main objectives of increasing economic benefits for Saskatchewan farms and promoting marketable attributes for consumers, Moats also believes that Saskatchewan growers are interested in the idea of sustainability — and have been for longer than it has been fashionable — for reasons beyond just increasing their profits.
“On a personal level I am very interested in sustainability, not for consumer interest but in terms of intergenerational transfer,” he says.
“The question will be, did our farm survive to be passed on to the next generation? And how can we continually be making improvements in this area? I think this idea is shared by growers everywhere.”