Can we survive without glyphosate? Lessons learned from Europe, Canada and Argentina

Take home messages

• In the 1970s, the herbicide glyphosate was developed, completely changing crop production practices.
• The intensification of crop production systems together with an increasing use of herbicides, including glyphosate, has a potential human and environmental cost.
• Consumers the world over want transparency in the use of agricultural chemicals, including synthetic fertilisers.
• A study tour to Europe, Canada and Argentina enabled us to discuss with growers, agronomists and researchers issues related to using glyphosate and other farm chemicals, farm practices in general, the political environment and how farming is viewed by the local and more general community.

Background

Grain farming in the 2020s is vastly different from 50 years ago. Before herbicides became available, weeds were controlled by multiple deep and shallow cultivations, often using a mould-board plough to invert the soil and bury weed seeds. In the 1970s, the herbicide glyphosate was developed by Monsanto and sold as Roundup®, completely changing crop production practices. Growers no longer had to cultivate or plough their fields to control weeds, and the previous year’s crop residues were retained. Glyphosate effectively kills most weeds, annual and perennial, and growers worldwide were able to adopt minimum or no-till farming practices which resulted in:

• greatly reduced levels of erosion, by both wind and water, previous crop stubbles were able to be retained and paddocks were no longer left bare after ploughing or cultivation
• optimised timeliness of sowing, increasing yield
• reduced GHG emissions because growers used less fuel (less tractor use)
• improvement in soil ‘health’. In minimum- and no-till crop establishment, the soil is not disturbed by ploughing, reducing soil compaction and, together with the residues from previous crops, helps to create a better environment for soil micro-organisms to increase soil biological activity and store soil carbon (further mitigating GHG emissions).

In the 1990s, Monsanto released Roundup Ready soybeans – a genetically modified (GM) crop in which the plant was resistant to Roundup (glyphosate), but the weeds in the paddocks were not, resulting in very effective weed control. In addition to Roundup Ready soybean, other crops such as maize, canola and cotton also have glyphosate resistant cultivars available and are widely sown. Some jurisdictions around the world do not allow the growing of GM crops, such as the EU, but even in Europe, there are some exceptions, albeit on small areas with a special permit.

The intensification of crop production systems together with an increasing use of herbicides has a potential human and environmental cost. Glyphosate is not the only herbicide which has increased in use over the last three decades worldwide (see, for example, Argentine pesticide ecotoxicity profiles for different crop production systems, Ferraro et al. 2020).

Public awareness and concern about issues related to farm herbicide and pesticide use in general is increasing (Marr 2020, Mie and Rudén 2022). The sustainability and safety of current crop production systems are widely questioned. In some countries, glyphosate use is banned for home and public garden use and is severely restricted on farmland. In France, glyphosate use is restricted to 1080g ai/ha/yr and is only available to no-till or minimum-till growers. French growers who plough are not able to use it. In Argentina, some country towns have banned the use of all agrichemicals, including artificial fertilisers, in designated areas surrounding the town, for example, in Pergamino, the agrichemical use exclusion zone is 1095m from the town’s boundary.

The EU has seen several reviews of agrichemical use, particularly for glyphosate. The latest review by the European Assessment Group on glyphosate submitted an updated renewal assessment report in September 2022 to the European Food Safety Authority (EFSA) and it is expected that the 27 EU member states will discuss the evidence for and against the use of glyphosate by July 2023 (EFSA glyphosate review).

Consumers the world over want transparency in the use of agricultural chemicals, including synthetic fertilisers. However, it is also very important for consumers to confront the reality that the earth is inhabited by 8 billion people, all of whom need to be fed. At the current level of development of large-scale food production, only industrialised agriculture, using agrichemicals and fertilisers, will be able to feed 8 billion people. Distribution and unequal access to food and resources between rich and poor nations remain hurdles still to be overcome.

The study tour took us to Europe, Canada and Argentina to learn from growers, agronomists and researchers about what is happening in relation to agrichemical use, in particular with glyphosate.

Growers, agronomists and researchers we met on the tour were open and ready to discuss not only issues related to using glyphosate, but also other farm chemicals (including synthetic fertilisers), farm practices in general, the political environment and how farming is viewed by the local and more general community. We sincerely thank the many growers, agronomists and researchers with whom we discussed many issues related to farming. It was, for us, a most enjoyable and educational time.

Results and discussion

Europe (EU member states and UK)

• The use of glyphosate in public and home gardens is banned in most EU jurisdictions.
• For agricultural production, glyphosate is available, but there are restrictions. These restrictions are not the same in all EU member states. For example, in France, glyphosate can be used only by minimum- or no-till growers prior to sowing, and the rate is restricted to 1080g ai/ha/yr. French growers who plough are not able to use glyphosate. In Germany, the maximum glyphosate rate is 1800g ai/ha/yr.
• There is no alternative broad-spectrum herbicide available in Europe. The use of paraquat is already banned.
• Since January 2022, it is forbidden in France to give advice on agrichemical use and the sale of products. Re-sellers are able to advise on how to use different products, but not advise on what or how much to use.
• In Germany, there are 77 pesticides under review for risk assessment to human health and environmental considerations. Glyphosate is not on this list because of its relatively low toxicological level (however at a political level, Germany is not likely to support the continued use of glyphosate).
• ‘Biological’ herbicide alternatives are being tried. We visited one large-scale trial in France where weed control efficacy of glyphosate is compared with ‘biological’ alternatives. It was set up two years ago and needs more time for differentiation between treatments.
• When assessing soil glyphosate residues between different farming systems, it is imperative to also measure soil AMPA (Aminomethylphosphonic acid), the residual product of glyphosate.
• In the EU, the production of canola is greatly reduced because neonicotinoid insecticides are banned. Growers regard insect control to be too difficult and have reduced the area sown to canola. There is an exemption in some jurisdictions for continued use of neonicotinoid insecticides, for example, in sugar-beet until 2023.
• Organic grain production has similar yields to minimum or no-till grown grain crops, but only on a per crop basis. Non-organic growers have a more intensive rotation (growing summer and winter crops often sequentially), whereas organic growers, because they need to plough and cultivate to control weeds, can only grow one crop per year resulting in lower land-use efficiency. Organic grain growers receive a premium price for their produce and additional subsidies, which means the income received from crop production is similar to that of growers who use pesticides and fertilisers.
• Cover crops are often planted between harvest of the winter crop and sowing the summer crop. Growers were enthusiastic about cover crops, but they also questioned:
  • What is the soil organic matter benefit of cover crops?
  • How much soil nitrate is used by cover crops? (High soil nitrate levels in cropping soils are a problem because of leaching of nitrate into groundwater which is used for town water supplies in Europe)
  • What are the root disease carry-over issues with different cover-crop species
  • Cover crops are sprayed with glyphosate just prior to sowing the summer crop. If the fields with cover crops need to be cultivated, it is unlikely that the practice of planting cover crops will continue because of time and cost constraints. Some growers were investigating using ‘crimpers’ to terminate cover crops but reported problems with controlling vetch.
• Mice are often a serious pest in no-till systems and mouse bait can be applied only by placing it directly in mouse holes, which is time consuming and expensive (another reason not much canola is sown).
• In France, growers who apply pesticides must use a scale which measures the total amount of active ingredient applied, named the ‘Frequency of Treatments (ITF)’. If the total score reaches a certain level, no other pesticides can be applied in that year.
• Some growers are using robotics to control weeds, and several are experimenting with alternative methods of weed control, such as between row mechanical soil disturbance, which is very difficult in paddocks with retained stubbles from previous years (that is, only suitable on paddocks which have been cultivated).
• Many growers raised the issue that if they must resume ploughing, it will mean:
  • Delay in timing: cultivation takes time and often results in sowing being delayed (with subsequent loss in yield)
  • Soil degradation from ploughing
  • Increased GHG emissions through the breakdown of soil organic matter and additional fuel consumption.
• Growers and agronomists said a detailed assessment of the impact of banning glyphosate on long-term crop yield and productivity must be undertaken before the product is banned (inclusive of an ecological assessment).
• Without glyphosate, it will be even more difficult to control problem weeds such as black grass (Alopecurus myosuroides).
• There is a need to communicate more effectively with the general community about food sources, how it is produced and how the world is going to feed an ever-growing population (currently at 8 billion).

Canada

• The Pest Management Regulatory Agency (PMRA) of ‘Health Canada’ regulates pesticide use under the Pest Control Products Act. In 2017, the PMRA full re-evaluation of glyphosate concluded there was no risk or concern for human health or the environment when used according to the label. Registration was resumed.
• In February 2022, the first ever intervention on a PMRA decision by the Federal Court of Appeal (brought to the Court by ‘Safe Food Matters’) occurred when the Court ordered the PMRA to review its decision to re-register glyphosate. As of November 2022, no decision has been made.
• August 2021: Maximum Residue Limits (MRL) increased for several herbicides, including glyphosate (to align with trading partners).
• If glyphosate were to be banned, growers identified ‘crop competition’ as the most likely method to achieve some level of weed control (where ‘crop competition’ can be achieved by early seeding, seeding at high rates, using narrow row spacings and growing competitive cultivars. Remote sensing for identifying weed patches, using rod weeders, weed wipers and shielded sprayers were also mentioned).
• Canadian growers do not see tillage (ploughing and cultivation) as a solution to ‘farming without glyphosate’. Tillage will result in soil degradation, erosion, soil structure decline, and a loss of soil organic matter, together with a subsequent increase in GHG emissions. In addition, tillage will require more diesel use, also resulting in an increase in GHG emissions.
• The loss of glyphosate will result in an increased use of other herbicides, without knowledge of their impact.
• Growing of Roundup Ready (RR) canola, soy, maize and sugar-beet has resulted in a large increase in the use of glyphosate (from 1998 to 2018, the increase was three-fold).
• Glyphosate is used pre-harvest to control weeds in RR crops.
• Many growers and consultants believe using glyphosate for desiccation is likely to be banned. It is banned already for malt barley and milling oats).
• It is essential to understand the environmental toxicity of adjuvants (such as wetters and surfactants) used in glyphosate, and other herbicide formulations.
• There is no regulatory requirement in Canada for recording pesticide use.
• Other herbicides which could possibly be used as glyphosate replacements and worthy of investigation are Group 13 clomazone; Group 14 saflufenacil; Group 14 pyraflufen; Group 28 tetflupyrolimet; Group 13 bixlozone; and Group 30 cinmethylin.
  Note - these herbicides will not be ‘substitutes’: they do not have the same ‘knockdown’ ability of glyphosate, but they do have activity on a broad-spectrum of weeds. Substituting other herbicides for glyphosate is likely to increase the total amount of herbicide applied (due to the reduced efficacy of other herbicides in killing a broad-spectrum of weeds).
• Acetic and/or pelargonic acid formulations in ‘biological Roundup’ need to be evaluated more extensively for weed control efficacy in annual and perennial weeds. In addition, these products have an unknown impact on soil biology. This also needs to be studied.

Argentina

• Over 90% of grain production is conducted by means of no-till farming practices.
• Most of the crop growing areas are double cropped: winter crops (wheat, some barley) and summer crops (soy, maize and sunflower).
• Cover crops are grown between winter and summer crops, primarily to provide cover to reduce bare ground and protect the soil from erosion, reduce weed pressure, retention of soil N (to reduce NO3 leaching) and, if using legumes in the cover crop mix of species, to fix additional N.
• Most country towns use groundwater for drinking and leaching of NO3 into groundwater is a major concern.
• An increasing number of country towns are banning the use of all pesticides and artificial fertilisers for a prescribed distance from the town’s perimeter (for example, in Pergamino, the ban applies to all agricultural land for 1km from the town’s boundary). There is no compensation for loss of production.
• The most common use rate of glyphosate is ~3000g ai/ha/yr.
• Argentina has a pesticide risk assessment tool, based on World Health Organisation (WHO) data, which uses pesticide acute toxicity to assess risk.
• Strong research and agronomy consulting networks such as University of Buenos Aires (Agriculture faculty) undertake detailed research into herbicide resistance; INTA (National Agricultural Technology Institute) work on cover crops, crop competition and other agronomic means to control weeds; and agronomy consulting network such as CREA (Regional Consortium of Agricultural Experimentation) work with 226 farm groups with over 2000 grower members to develop, test and share new technologies.
• Several organisations, including CREA, are investigating and testing alternatives to boom sprayer pesticide application, such as robotics, microwave and laser technology, and nano-encapsulation of herbicides which release active ingredients slowly without resulting in detrimental impact on soil biota (soil organisms).
• Research trials to develop an ‘Environmental Impact Index’, for all agrichemicals have been established.
• Organic farms receive higher prices for organic classified grain without which they would not be financially viable.
• Argentina is a member of the SPRINT (Sustainable Plant Protection Transition) project (EU based project to study transition pathways to reduced chemical inputs).

Conclusion

Our recommendation is to establish a co-ordinated network of trials and demonstrations with research organisations and farming systems groups to communicate, identify and demonstrate alternative practices to weed management.

• Work with a group of growers who keep good records of farm chemicals (type, rate, date) and soil test extensively for glyphosate and AMPA, and other farm chemical residues in soil and grain. It will be important to first determine the variability within a paddock, or even soil type within a paddock, for glyphosate/AMPA residues, to be able to develop a comprehensive, extensive, and accurate sampling regime (one of the lessons learnt from the GRDC project on soil P and N sampling).
• Long term replicated trials with FSGs (Farming Systems Groups) using experimental plot and large-scale trials using farm machinery, to quantify the impact on productivity and sustainability of glyphosate-free crop production compared with current practices: crop density (plant population, sowing rate, row width and other planting options, crop types, stubble management), weed population dynamics (time of emergence, within crop distribution, flowering and seeding times). Inclusive of detailed measurements of soil and grain glyphosate/AMPA residues.
• Impact of cover crops on weed suppression, taking into consideration soil water and soil nitrogen dynamics of cover crops versus chemical weed control during the summer fallow phase.
• Assess impact of cover crops on
  • soil health (soil organic C, soil microbial populations)
  • operations (time and fuel use, inclusive of GHG emissions)
  • crop yield and financial returns.
• Investigation of alternative means for controlling weeds (within row soil disturbance, robotics, drones).
• Using the data and outcomes collected from the above small- and large-scale trials and observations, model the impact, in different environments and soil types, on
  • weed population dynamics
  • production, profitability and sustainability
  • financial consequences.
• For different farming systems, calculate the impact of pesticide (herbicides, fungicides and insecticides) use on human health and environmental parameters, for example, possibly using similar tools as developed in Argentina, such as the Environmental Impact Index(EIQ) which is based on the ecotoxicological rating of individual pesticides.
• Greater clarity in the separation of agronomic advice and sales of agrichemicals may result in better environmental outcomes through optimisation of chemical inputs resulting in improved public perception of modern farming practices.
• Weed control efficacy of other herbicides which have a relatively wide range of effectiveness in controlling weeds:
  • Group 13 clomazone (Magister Command®)
  • Group 14 saflufenacil (Sharpen®)
  • Group 14 pyraflufen-ethyl (Sledge®)
  • Group 28 tetflupyrolimet (not registered in Australia)
  • Group 13 bixlozone (Overwatch®)
  • Group 30 cinmethylin (Luximax®)

Note - these herbicides will not be glyphosate ‘substitutes’ – they are not ‘knockdown’ herbicides but they do have activity on many weeds and may well assist in weed control if glyphosate was no longer available.

References

Ferraro DO, Ghersa F, de Paula R, Duarte Vera AC, Pessah S (2020) Historical trends of the ecotoxicological pesticide risk from the main grain crops in Rolling Pampa (Argentina). PLOS ONE 15(11), e0238676.

EFSA Glyphosate Overview 

Marr H (2020) Can we farm without glyphosate? 2019 Nuffield Scholar Report, Lincoln, New Zealand.

Mie A, Rudén C (2022) What you don't know can still hurt you – underreporting in EU pesticide regulation. Environmental Health 21, 79 doi: 10.1186/s12940-022-00891-7.

Contact details

Harm van Rees
Cropfacts Pty Ltd
Bendigo VIC 3550
Email: harm@cropfacts.com.au

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