Glyphosate largely gained public attention since the 2017 EU member states vote on the renewal of its commercial license. This follows a bigger current of public awareness on pesticides-related risks. In France, the national plan of actions Ecophyto aims at reducing by 50% by 2025 the use of plant protection products. Since 2019, this plan restricts public and domestic uses of pesticides to biocontrol and substances allowed in organic farming [1]. Would a glyphosate ban benefit biodiversity and how ? Keep on reading to find out more.
A definitive answer to glyphosate impact on biodiversity is hard to get. Scientific reports test different glyphosate formulations, species, exposure times, and treatment doses [4]. Degradation products and persistence times greatly vary because it depends on co-reactants found in water and in soil. Not only can glyphosate degradation products be harmful, but the mix of additives used in commercial formulas can be as dangerous. Additives mutually increase their impacts, resulting in synergistic effects. Proven impacts of glyphosate on biodiversity, glyphosate degradation products or additives include: decrease in soil beneficial fungi and bacteria, perturbation of reproductive cycles and activity of earthworms, perturbation of digestive system of honeybees, toxic effects (general impact on the life cycle) on algae, plants, fish, invertebrates and mammals [2].
Over 90% of glyphosate is used for agricultural purposes worldwide and it amounts for over 30% of pesticides sold in the EU [2,3]. Other purposes include weed control in railway lines, public areas and private gardens [2] (Fig. 1). A glyphosate ban has important consequences on agricultural practices, yield, and profitability. Commonly considered sustainable practices such as no-tillage and conservation agriculture are the systems that might face the biggest challenge without glyphosate [5].
Conservation agriculture is based on three principles: minimum mechanical soil disturbance, permanent soil organic cover, and species diversification [6]. Conservation agriculture decreases soil erosion and the use of fossil fuels while benefiting biodiversity [7]. However, it heavily relies on herbicides to control weeds instead of conventional, negatively-soil-impacting tilling [8].
Some opponents to a glyphosate ban fear that substitute products might be worse [9]. Relying on only one product (glyphosate) or one method (chemical plant protection) to fight against the creativity of nature will inevitably fail (see our last blog post about glyphosate-resistant weeds). Instead, a combination of methods can be implemented (Fig. 2): preventive practices to reduce weed germination (false seedbed, intercropping), monitoring of crops to better understand the conditions and impacts of weed germination, mechanical control (for instance reduced tilling to the first cm of soil), biological control with other crop, animal integration into the cropping system, long (up to 9 years) crop rotation cycles, or plantation of cover crop and perennial species (trees and hedges) [2].
These methods require additional investment and work, especially in the first years of transition but quantifying them depends on current agricultural practices of a farm. Indicators such as yield and productivity are commonly used to compare cropping systems with and without glyphosate. However, many ecosystem-services - and their economical value - should also be taken into account in the comparison: increase in soil fertility [10,11] leading to a reduced use of fertilizers, increase in weed diversity leading to higher inter-weed competition [12, 13], increase in weed-feeding insects on which birds and bats prey (providing several sources of biocontrol) [2], increase in pollination [14, 15], decrease in soil and freshwater contamination [2,4] which have a long-term impact on human health, and increase in well-being thanks to safer working conditions for farmers, valorization of farmers' knowledge, technology reappropriation, and increase in trust from consumers [16]. A recent meta-analysis even shows that all these benefits can be combined with reasonable yields in diversified cropping systems [17].
Weeds are considered undesirable because our agricultural systems are limited to the production of a few crops. However, from a biodiversity angle, weeds are far from useless elements of an ecosystem. They offer food and habitat, increase pollination, harbour biocontrol solutions, cover bare ground from erosion and nutrient loss, and protect beneficial microbial communities in soil [2]. You can contribute to obtaining more information about weeds by joining this citizen-science program: https://www.vigienature.fr/fr/flore/sauvages-de-ma-rue .
At GreenPRAXIS, our job is to offer nature-based solutions and quantify their benefits so it is safe for humans and the environment while creating economical value.
References:
[2] : UN environment, 2018, Early warning, emerging issues, and futures (10). https://stg-wedocs.unep.org/bitstream/handle/20.500.11822/26729/foresight_brief_010.pdf?sequence=1&isAllowed=y
[3] : Antier, C., Andersson, R., Auskalnienė, O., Barić, K., Baret, P., Besenhofer, G., Calha, I., Carrola Dos Santos, S., De Cauwer, B., Chachalis, D., Dorner, Z., Follak, S., Forristal, D., Gaskov, S., Gonzalez Andujar, J. L., Hull, R., Jalli, H., Kierzek, R., & al. (2020). A survey on the uses of glyphosate in European countries. INRAE. https://doi.org/10.15454/A30K-D531
[4] : Leoci, Raffaella, and Marcello Ruberti. 2020. “Glyphosate in Agriculture: Environmental Persistence and Effects on Animals. A Review.” Journal of Agriculture and Environment for International Development (JAEID) 114 (1): 99–122. https://doi.org/10.12895/jaeid.20201.1167.
[5] : Kudsk, Per, and Solvejg Kopp Mathiassen. 2020. “Pesticide Regulation in the European Union and the Glyphosate Controversy.” Weed Science 68 (3): 214–22. https://doi.org/10.1017/wsc.2019.59.
[6] : FAO, 2021. https://www.fao.org/conservation-agriculture/en/
[7] : Palm, Cheryl, Humberto Blanco-Canqui, Fabrice DeClerck, Lydiah Gatere, and Peter Grace. 2014. “Conservation Agriculture and Ecosystem Services: An Overview.” Agriculture, Ecosystems & Environment, Evaluating conservation agriculture for small-scale farmers in Sub-Saharan Africa and South Asia, 187 (April): 87–105. https://doi.org/10.1016/j.agee.2013.10.010.
[8] : Scopel, Eric, Bernard Triomphe, François Affholder, Fernando Antonio Macena Da Silva, Marc Corbeels, José Humberto Valadares Xavier, Rabah Lahmar, et al. 2013. “Conservation Agriculture Cropping Systems in Temperate and Tropical Conditions, Performances and Impacts. A Review.” Agronomy for Sustainable Development 33 (1): 113–30. https://doi.org/10.1007/s13593-012-0106-9.
[9] : Fogliatto, Silvia, Aldo Ferrero, and Francesco Vidotto. 2020. “Chapter Six - Current and Future Scenarios of Glyphosate Use in Europe: Are There Alternatives?” In Advances in Agronomy, edited by Donald L. Sparks, 163:219–78. Academic Press. https://doi.org/10.1016/bs.agron.2020.05.005.
[10] : García-Pérez, José Antonio, Enrique Alarcón-Gutiérrez, Yareni Perroni, and Isabelle Barois. 2014. “Earthworm Communities and Soil Properties in Shaded Coffee Plantations with and without Application of Glyphosate.” Applied Soil Ecology, XVI International Colloquium on Soil Zoology & XIII International Colloquium on Apterygota, Coimbra, 2012 – Selected papers, 83 (November): 230–37. https://doi.org/10.1016/j.apsoil.2013.09.006.
[11] : Gaupp-Berghausen, Mailin, Martin Hofer, Boris Rewald, and Johann G. Zaller. 2015. “Glyphosate-Based Herbicides Reduce the Activity and Reproduction of Earthworms and Lead to Increased Soil Nutrient Concentrations.” Scientific Reports 5 (1): 12886. https://doi.org/10.1038/srep12886.
[12] : Garrison, Andrew J., Adam D. Miller, Matthew R. Ryan, Stephen H. Roxburgh, and Katriona Shea. 2014. “Stacked Crop Rotations Exploit Weed-Weed Competition for Sustainable Weed Management.” Weed Science 62 (1): 166–76. https://doi.org/10.1614/WS-D-13-00037.1.
[13] : Storkey, J, and P Neve. 2018. “What Good Is Weed Diversity?” Weed Research 58 (4): 239–43. https://doi.org/10.1111/wre.12310.
[14] : Battisti, Lucas, Michele Potrich, Amanda Roberta Sampaio, Nédia de Castilhos Ghisi, Fabiana Martins Costa-Maia, Raiza Abati, Claudia Bueno dos Reis Martinez, and Silvia Helena Sofia. 2021. “Is Glyphosate Toxic to Bees? A Meta-Analytical Review.” Science of The Total Environment 767 (May): 145397. https://doi.org/10.1016/j.scitotenv.2021.145397.
[15] : Luo, Qi-Hua, Jing Gao, Yi Guo, Chang Liu, Yu-Zhen Ma, Zhi-Yong Zhou, Ping-Li Dai, Chun-Sheng Hou, Yan-Yan Wu, and Qing-Yun Diao. 2021. “Effects of a Commercially Formulated Glyphosate Solutions at Recommended Concentrations on Honeybee (Apis Mellifera L.) Behaviours.” Scientific Reports 11 (1): 2115. https://doi.org/10.1038/s41598-020-80445-4.
[16] : Müller, Birgit. 2020. “Glyphosate—A Love Story. Ordinary Thoughtlessness and Response‐ability in Industrial Farming.” Journal of Agrarian Change, no. 21: 160–79. https://doi.org/10.1111/joac.12374.
[17] : Tamburini, Giovanni, Riccardo Bommarco, Thomas Cherico Wanger, Claire Kremen, Marcel G. A. van der Heijden, Matt Liebman, and Sara Hallin. 2020. “Agricultural Diversification Promotes Multiple Ecosystem Services without Compromising Yield.” Science Advances 6 (45): eaba1715. https://doi.org/10.1126/sciadv.aba1715.
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