🚜 Will the transition to organic oat reduce ecological impacts?

Version française

Almost two years ago, I began to write an article (in French but translatable) on the ecological impacts of organic agriculture compared to non-organic agriculture (called conventional). International data strongly supported the article, but I wished I had data from the Québec province (Canada) other than an institutional 2011 report, which itself admitted having very little data from Québec. Since then, I haven't read any really reliable Québec study... until my colleague from UQAC, Maxime Paré, wrote to me.

Hello Serge-Étienne, I hope you are well. I think our recent paper should interest you 😛. https://authors.elsevier.com/c/1eo0W3QCo9f8Lc (my translation from French)

The paper (Viana et al., 2022), of which Maxime Paré is co-author, compares the production of organic and conventional oats with a life cycle assessment.

Warning. A life cycle assessment cannot count everything. That of Viana et al. (2022) is limited to the direct impacts of two oat production sites during a single season. The LCA remains localized in space and time, and represent only potential impacts, not measured ones. For a more comprehensive perspective, I suggest a careful reading of Clark and Tilman's (2017) meta-analysis.

Leverage points for each cropping system

The paper first identifies the most impactful activities of each cropping system (organic and conventional) on two resolutions, endpoint and midpoint. The endpoint impacts consist of three indicators for each system : ecosystems, health of exposed people and depletion of resources. Midpoint impacts are broken down into 18 aspects: climate change, acidification, eutrophication, ecotoxicity, land use, scarcity of fossil resources, etc.

Results: the impacts of synthetic and organic fertilizers dominate, in particular the midpoint impacts related to air and water pollution. On the one hand, the production of synthetic nitrogen fertilizers is water and energy intensive, and natural gas (including that of Gazprom) is used as a source of hydrogen – note that other options are becoming more and more affordable. The production of manure for organic farming, considered as an indirect impact, is not taken into account either for its externalities in the production of green manures, or as a by-product of livestock farming. This is quite understandable, as it would be difficult to displace the burden of the ecological impacts of animal husbandry on manure rather than on its main economic role (e.g. meat). But considering manure as a recycled resource in a system (a joint product) and not a by-product would consequently attribute to it a small part of the impacts of livestock farming, and would increase the impacts of the practices that make use of it.

Viana et al. (2022), figure 2. Full-width image

The impact sectors are probably the most interesting results of the article from a practical point of view. But to guide public policies, the problem can be presented in terms of an organic/conventional comparison.

Comparative analysis

The organic/conventional comparative analysis is reported on three relative bases (or functional units): impacts by cultivated area (e.g. CO2eq / hectare), by food mass (e.g. CO2eq / kg of grain) and by monetary income (e.g. CO2eq / $). The authors pay little attention to the income base, an economic rather than an ecological indicator, but remain ambivalent about the other two, preferring impacts by food mass to measure ecological efficiency and impacts by area to measure the total impacts. Yet (this is my only major criticism of the article), the impact of cultivated area does not mean a total impact on ecosystems, any more than the impact of the food produced. To measure a total impact, we would rather go on a case-by-case basis, depending on the concentration of agricultural activities in a watershed, the nature of these activities and the nature of the watershed, etc. This is why, for a point of view independent of the host ecosystem (which is imperfect, I agree), it is better to focus on the ecological effectiveness of practices, by food mass, which measures the impact of the food – the base per surface risking presenting as favourable practices relying on the dilution of the impacts.

The authors present their results in a table, from which I retrieved the data to present them graphically.

Data from Viana et al. (2022), table 4. Fullwidth image

The endpoint impacts show that, on a food functional basis (by mass-produced), organic oats had a more deleterious impact than conventional on the depletion of resources (albeit marginally), on ecosystems, and on human health.

As for the midpoint impacts, organic performs worse for 8 of the 10 ecological indicators, in particular the one that I have coloured in red: the occupation of the territory, which contributes to 70% of the total impact linked to the biodiversity. The authors nevertheless note that cultivated areas are not necessarily devastated, and that the impacts on the territory are not uniform from one cultivation practice to another.

Note. Although studies tend to show that organic is host to greater biological diversity, an agricultural site is not a wild habitat and should not – with few exceptions – be considered as a species conservation area. Organic, regenerative agriculture, permaculture, etc., are not species conservation strategies.

The ecological sectors where conventional did worse are linked to the ecotoxicity of water, due to differences in the use of pesticides. This corresponds to the results of a Swedish report published in 2016. But also, the LCA includes the production and transport of fertilizers and pesticides, the balance of which also favours organic farming. Nevertheless, we find a lower terrestrial ecotoxicity in conventional. The reason? Manure is not a commodity accessible at the door. Luciano Viana's explanation shows the finesse of his ACV.

Organic production requires a very large amount of transportation for chicken manure. Among the main causes, there are copper emissions due to the wear of the braking system of trucks. Indeed, the emissions of brake particles are almost all less than 10 μm and consist largely of significant proportions of heavy metals. – Luciano Viana, personal communication (my translation from French).

While organic has a greater impact with a narrow margin on the depletion of resources in general (endpoint), certain aspects favour it more punctually, not concerning fossil fuels as we often hear, but mainly concerning the contribution to the water balance (use of water in relation to the renewal of the resource). Luciano Viana, first author, explained to me that the difference was mainly due to the synthesis of nitrogenous fertilizers, a water-intensive process – I repeat, the LCA externalizes the impacts of the production of organic fertilizers.

As for the impacts on human health, they are linked to the people exposed to the production, and not to the consumers. The aerial suspension of fine particles and the formation of ozone play against the organic, the non-carcinogenic toxicity playing against the conventional. The carcinogenic toxicity is for all practical purposes equivalent.

Don't presume impacts from the label

This is the first Quebec study comparing the impacts between organic and conventional management using a life cycle analysis. The results obtained do not clash with the scientific literature on the subject, which shows that the ecological performance of organic farming is inferior to conventional farming. For the most important ecological indicators, organic does worse than cropping systems (grouped under the term “conventional”) which have not, in most cases, been designed to be ecological.

Finally, a message that could be drawn from the article is that it is contraindicated to presume the impacts of agricultural production according to the presence/absence of the organic label. Public policies in agriculture, and more broadly in agri-food, should be guided not by adherence or not to a collection of standards developed on the fringes of science, but by the expected or proven effects of agricultural practices and food products.

Huge thanks to Luciano Viana and Maxime Paré who answered my questions with enthusiasm.

Comment on Twitter

Comment on Mastodon

#en #agriculture