Author: Tamara Baumann

Meadow fescue is an important fodder grass on temporary leys in Switzerland. Agroscope tested 24 varieties of meadow fescue on six sites. Three new cultivars proved impressive in the growing trials and are designated for variety recommendation.

Meadow fescue is an important fodder grass of moderately intensively managed permanent meadows of the Swiss Central Plateau and central mountain locations. On temporary leys, it plays an important role as a high-yielding, high-quality and robust meadow grass. It is used primarily in the three-year mixtures intended for low-to-moderate intensity management, or in which ryegrasses cannot be used, depending on location.  Meadow fescue yields are particularly high for the first regrowth. With early use, moreover, it provides roughage with a high energy value.

24 meadow fescue varieties field-tested

From 2023 to 2025 Agroscope tested a total of 24 varieties of meadow fescue (Festuca pratensis) in terms of their agronomic properties. The trials were sown at six different sites. Yield, juvenile development, vigour, competitive ability, persistence, infestation with leaf diseases, winter-hardiness, digestibility of the fodder and suitability for cultivation at higher altitudes were investigated.

Three new varieties meet the agronomic requirements

Based on the results, three new varieties have managed to clear the hurdles for inclusion in the List of Recommended Varieties of Fodder Plants: Tetradonia, Tenorio and FP 1745, which captured first, second and third place, respectively, for the entire test range. Tetradonia and Tenorio are tetraploid varieties, like the already-recommended variety Tetrax. Both varieties impressed with their outstanding digestibility ratings, and were also distinguished by fine homogeneous stands, very good juvenile development and high resistance to leaf diseases. Tetradonia is also high-yielding, whilst Tenorio’s very good suitability for higher elevations should be stressed. FP 1745, a diploid variety, delivered outstanding results mainly in terms of yield, vigour and persistence, and also impressed with good winter-hardiness. The three varieties enhance the range of varieties on offer but cannot currently be recommended since they do not yet meet the legal requirements for being placed on the market.

Paradisia and Pardus removed from the List

According to the most recent variety tests, the previously recommended varieties Paradisia and Pardus must be removed from the List of Recommended Varieties, as they no longer meet a number of the current requirements. Both varieties can still be used as recommended varieties until 31 December 2028.

Seeds are generally routinely treated with plant-protection products to safeguard yields. A study conducted on wheat seeds and based on new field data shows that when disease pressure is low, this routine treatment offers no benefit in many cases.

Plant diseases are among the main reasons for yield losses worldwide. Seed treatments – usually chemical-based – are therefore widely used to protect crops at an early stage. This practice, however, is coming under increasing critical scrutiny: the risks for the environment, water quality and biodiversity as well as the plant-protection product reduction targets, increase the need to take action.

At the same time, alternative non-chemical methods are being developed, such as thermal treatments or physical procedures. The efficacy of these methods, however, remains difficult to assess, particularly under practical conditions, owing to the lack of data coming from the field.

Alternatives to chemical seed treatments: comparison in the field

A three-year study on winter wheat provides data on the effects of chemical or alternative treatments (Thermoseed, electron beam and mustard-based treatments) of seed on agronomic parameters such as yield, protein content, thousand-kernel weight and micronutrients, as well as on bacterial and fungal microorganism communities associated with winter wheat. This multiyear field trial conducted in Switzerland thus helps determine the conditions under which seed treatments genuinely contribute to the safeguarding of yields.

No effect on yield or quality

Neither the chemical nor the alternative seed treatment led to measurable improvements in key agronomic indicators such as yield, protein content or kernel weight. The results show that under the practical conditions of the study, these treatments brought no additional benefit to production.

No change in soil or plant microbiology

The composition of the microbial communities at root or seed level also remained unchanged, regardless of the treatment chosen. Hence, no effect, either positive or negative, on soil microbial processes was noted.

Importance of disease pressure

The seed lots used only exhibited low levels of pathogen infection. In this context, no benefit from the treatments could be demonstrated in the case of either the alternative or chemical procedures. The results suggest that seed treatment offers few advantages when disease pressure is low. Furthermore, in our field trial, alternative treatments showed no harmful effect on the plants, and could therefore be the subject of additional studies.

Fungicide seed coatings protect seeds and safeguard yields, but can adversely affect beneficial soil fungi. Recent findings from various experimental systems – from controlled laboratory trials to real-life conditions in the field – show how dramatically these effects can vary.

Fungicide seed coatings are common in agriculture to protect young plants from diseases and ensure stable yields. However, fungicides may also negatively impact non-target organisms, such as beneficial soil biota, in addition to harmful fungi. Among these beneficial organisms are arbuscular mycorrhizal fungi, which can improve plant nutrient uptake and soil structure. In policy and administrative circles, striking a balance between ensuring stable yields and promoting ecological functions is a key concern, e.g. in the context of sustainable farming and soil health. Previous evaluations of seed coatings often focused on short-term effects or individual aspects, paying less attention to how impacts may differ across a range of levels – from the spore, to the field performance of mycorrhizal fungi. Recent research provides nuanced insights into this issue and shows that the impacts are not uniform.

Different effects depending on experimental system

The study shows that fungicide seed coatings in maize affect mycorrhizal fungi differently, depending on scale. At the level of individual fungal spores, germination can be significantly inhibited. These effects, however, cannot be extrapolated directly to plant growth or to maize yields in the field. This means that the informative value of individual laboratory tests for real-world use comes with caveats.

Attenuation of effects in the field

The negative effects of fungicide seed coatings on mycorrhizal fungi are less pronounced in the field trial than under controlled laboratory conditions. Environmental factors such as soil characteristics, microorganisms and climatic conditions influence the real-world effect. In many cases, the plants remain colonised with mycorrhiza – although to a lesser extent – despite the seed coating.

Limited impact on plant performance

As a rule, the application of fungicide seed coatings has only a slight effect on the colonisation of the maize roots with mycorrhiza and on the resulting plant performance. Whilst individual effects on the symbiosis between plant and fungus are visible, these do not necessarily lead to measurable losses in agricultural production. This suggests that plants and soil organisms possess a certain ability to adapt to seed coatings.

Mixtures of several forage-plant species systematically increase yields with lower fertiliser input. Higher temperatures enhance the benefits of these mixtures, making them a key component of climate-change adaptation.

Cultivating forage-plant species as mixtures improves resource efficiency. Agroscope investigated this in a global study recently published in the journal Science. Mixtures of several forage plants systematically increase yields with lower fertiliser input. Higher temperatures enhance the benefits of these mixtures, making them a key component of climate-change adaptation.

Worldwide network of 26 experimental sites

The study summarises the findings of a global network of experiments conducted on 26 sites around the world in the temperate climate zone. Agroscope, the Swiss Confederation’s centre of excellence for agricultural research, carried out the experiment together with partners from Europe, North America, China and New Zealand.

Six species give greater yields than one or two

In Switzerland, only mixtures of more than two forage plants are sown in the rotation. In many other countries, and for simplicity’s sake, it is mostly grass monocultures (which require high nitrogen-fertiliser input) or a combination of just one grass and one legume that are sown. The Swiss strategy of planting mixtures of several species is now also catching on internationally. Researchers investigated which mixtures of up to six different forage-plant species would improve yields whilst lowering dependence on nitrogen fertilisers.

The findings showed that grassland mixtures of several species achieved higher yields than the monocultures due to beneficial interactions between the species. The mixtures yield was much higher than the sum of the individual parts. A mixture of grasses, legumes and herbs delivered an 11% higher yield than a grass monoculture receiving more than twice as much nitrogen fertiliser, and an 18% higher yield than a simple grass-legume mixture with the same fertiliser input.

The warmer the climate, the greater the yield advantage of multispecies mixtures

And further good news – the study shows that warmer temperatures enhance the advantages of grassland mixtures. With increasing temperatures, the yield advantage of the multispecies mixtures with legumes and herbs rose along the climatic gradient of the sites, underscoring the potential of mixtures for climate-change adaptation.

It was not just in Switzerland that multispecies mixtures had an advantage. The study demonstrates convincingly that this Swiss tradition also improves resource efficiency worldwide and supports agriculture’s adaptation to climate change.

A recently published paper by Agroscope gives an overview of preventive measures and non-chemical methods of controlling weeds, diseases and pests in arable farming and field vegetable cultivation.

Integrated pest management is a concept combining various methods to keep harmful organisms below the economic threshold. Preventive measures form the broad foundation here, with decision-making tools providing support in determining the right time to apply any control measures (Figure 1). If control measures are required, biological, biotechnical and physical (i.e. non-chemical) measures are to be prioritised wherever possible. Only then, if these measures prove unsuccessful, are chemical plant protection products to be used. This publication gives an overview of the preventive measures and the non-chemical methods for controlling weeds, diseases and pests in arable crops and field vegetables, as well as an assessment of the practical suitability of these methods based on our current state of knowledge.

Weeds

Weed pressure can be reduced through preventive measures such as balanced crop rotations and optimised cultivation methods; weeds can be controlled in the crop by mechanical and physical methods. These methods are more time-consuming as well as less effective in the case of problem weeds, heavy weed infestation and unfavourable weather conditions.

Diseases

The main preventive measures are healthy seed, robust varieties, balanced crop rotations and good field hygiene. With these measures, the use of fungicides can largely be avoided in many arable crops with only a slight reduction in yield. In potato, sugar beet and field vegetables, preventive measures – especially in the case of disease-resistant varieties – can reduce fungicide use. At present, however, completely dispensing with fungicides is often not feasible.

Pests

In many arable crops such as cereals and maize, pests are usually adequately controlled with preventive measures such as crop rotation and the protection of beneficials. However, oilseed rape, potatoes, sugar beet and field vegetables are infested by pests with a high damage potential. A number of approaches have proven effective, such as crop rotation for sugar beet or the use of Bacillus thuringiensis to control Colorado potato beetles, and undersowings in oilseed rape have shown potential. Additional measures are still being researched.

Quality requirements and food prices

Due to the high-quality demands of the market, challenges in vegetable production are greater than in arable farming. With a view to reducing the use of plant protection products, it might be worthwhile to question the private-law quality standards for vegetables in terms of aspects that are purely optical or are non-hazardous in terms of food safety, and perhaps lower these standards and tolerate a certain level of pest infestation. Furthermore, the additional expenditure and higher yield-loss risks associated with alternative plant protection measures could be counterbalanced by higher food prices or other measures to render the crops economically profitable.

Thanks to the selection of new clones, the ‘Räuschling’ grape variety has become more consistent in terms of cultivation and wine quality. Multi-year trials have shown that four new clones stabilise yield and quality and reduce the risk of both berry splitting and Botrytis (grey mould) infestation.

‘Räuschling’ is a white-wine grape variety of local historical importance, chiefly cultivated around Lake Zurich (2024: 28.3 ha, 72% in Zurich Canton). It is also considered challenging to grow: the berries tend to crack or split before the harvest, which favours Botrytis and increases the effort involved in selection and harvest.

Agroscope’s clone collection: the key to Räuschling’s genetic diversity

Since the 1970s, Agroscope has been carrying out a clone selection programme to improve yield security, disease resistance and grape quality. The current clone collection (20 genotypes) is the only one of this variety in the world, and is thus key for genetic diversity.

In Stäfa (Canton of Zurich), fifteen single-Guyot-pruned clones on an identical rootstock (3309C) were compared between 2015–2021, with Reference Clone 42 serving as the benchmark. Despite years characterised by extreme weather conditions (late frost/hail in 2017; wet summer in 2021) several clones reached the yield target of 1 kg/m². Must weights fluctuated within the narrow range of ~80–84 °Oe (Fig. 1); acid buffering and pH (~3.1) were similar across clones; oenological differences remained small.

The newly selected clones compared: differences in yield, Botrytis resistance and wine profile

• Clone 3: Very consistent yields, loose clusters, low susceptibility to splitting, lower tendency to Botrytis; top sensory rating; high formol index (yeast-available nitrogen).
• Clone 25: Highest yield potential together with relatively high sugar content; very loose clusters; in individual cases (2017/2019) more Botrytis, otherwise moderate susceptibility; sensory attributes were well rated.
• Clone 28: Higher-than-average sugar content, loose clusters, tendency towards less splitting/Botrytis; sensory attributes highlight fruity notes.
• FAW ‘rot’ (red-skinned): High yields with a relatively high must weight; little Botrytis despite compact clusters; fruity profile characteristic of the variety.

Mixed-clone plantings enhance resilience of ‘Räuschling’ grape variety

Important for practitioners: mixed plantings of several clones increase resilience, since characteristics complement each other depending on the vintage (e.g. high yields vs. susceptibility to splitting). This supports quality and yield, especially in years with precipitation before the harvest. Clones 3 and 25 are available; Clone 28 and FAW ‘rot’ are currently undergoing the approval process. The clone collection remains strategic for preserving diversity and for the ability to react adaptively to climate change.

Incorporating the SOM:clay ratio in the Principles of Agricultural Crop Fertilisation in Switzerland (PRIF) allows us to give more specific agronomic advice at each site based on a broader consideration of soil quality.

Soil organic matter (SOM) is the main indicator of soil quality. The SOM content of agricultural soils is strongly influenced by agricultural practices, and a certain percentage of these soils are in a degraded state. It is therefore crucial, particularly for farmers, to be able to interpret the SOM levels revealed by the soil analysis in order to guide crop management choices.

The Principles of Agricultural Crop Fertilisation in Switzerland (PRIF) provide a grid for interpreting the SOM content of soils which generally serves as a reference for the interpretation of the analyses. However, this grid has scarcely evolved since the 1980s and nowadays focuses on the function of supplying nitrogen (N). This suggests a significant potential for optimisation.

The SOM:clay ratio is a simple soil quality indicator whose thresholds are based on the soil structure quality potential. The SOM:clay ratio interpretation scheme is calibrated to the ’VESS’ (Visual Evaluation of Soil Structure quality) method.

The study conducted here aimed to evaluate the relevance of the SOM:clay ratio for interpreting the SOM content of the agricultural plots with a view to laying the foundations for a possible evolution of the PRIF interpretation grid. To this end, the thresholds defined in the PRIFs were compared with those of the SOM:clay ratio and the differences in assessment depending on method were highlighted for a selection of 184 FRIBO (Fribourg Soil Monitoring Network) plots.

The SOM:clay ratio provides greater nuance

The results of the study show that the PRIFs divide the plots into two groups: on the one hand, the majority of the arable land comprising the soils with the least SOM, classified as having an adequate SOM content, and on the other hand, a group comprising the arable land with the most SOM and the permanent grasslands, classified as ‘rich’. The assessment based on the SOM:clay ratio provides greater nuance on the SOM content of the arable land, indicating in particular that this content is considered inadequate in one-third of all cases.

Towards more specific agronomic advice

The study thus highlights the fact that in its current form, the PRIF interpretation grid does not constitute an adequate tool for effectively guiding farmers in managing the SOM of their fields. Incorporating the SOM:clay ratio in the PRIFs would enable a better differentiation between fields with very different SOM content but which are all currently classified as being at least adequate. The knowledge acquired will serve to update the PRIF chapter ‘Soil Properties and Analyses’.

Wines produced from resistant grape varieties are in the ascendant in Swizerland. Consumers are showing that they are open to them. The market penetration of these wines, especially in the catering sector, could be improved through better communication.

Against a backdrop of climate change and increasing research into sustainable viticulture, the use of grape varieties that are naturally resistant to fungal diseases would appear to be a promising option. Nevertheless, it is assumed that the market penetration of these grape varieties is sometimes curbed by their lukewarm consumer acceptance, even in the absence of systematic evidence of this.

Within this context, Agroscope conducted a study with three complementary objectives: to evaluate the current situation regarding the planting of resistant grape varieties in Switzerland; to summarise the latest consumer studies concerning these grape varieties; and to analyse their current presence on Swiss restaurant menus.

Limited but growing area

Although the area planted with resistant grape varieties remains limited – 540ha out of 14,484ha – it is on the increase, with German-speaking Switzerland having a substantial lead at this stage. The main resistant red grape variety planted in Switzerland is Divico, followed by Carbernet Jura. The main resistant white grape variety is Souvignier Gris, followed by Johanniter.

Consumer openness

In a recent study investigating Swiss consumer acceptance of resistant grape varieties, three factors were identified as levers with a potentially significant impact: the sensory quality of the wines; consumer wine knowledge level; and consumer familiarity with resistant grape varieties.

Here, we also show that consumers are open to resistant grape varieties for different consumption occasions and appear willing to incorporate them in their consumption habits.

Restaurateurs indicate need for support

A study of the menus of 450 catering establishments reveals that several already offer these wines on their menus. The distribution observed at production level is broadly reflected in the wine lists of the catering establishments.

The study asked restaurateurs what factors would encourage them to add this type of wine to their menu, as well as what factors would explain their lack of interest. The analysis of their responses reveals a variety of positionings. Several restaurateurs expressed a qualified openness to including these wines, motivated by the desire to diversify their wine lists and by values associated with sustainability. The inclusion of new products also appears to be strongly conditioned by the offerings of their usual winegrowers and suppliers; this dependence underscores the importance of good communication and collaboration between producers and restaurateurs to facilitate adoption. Several professionals insist that the adoption of this type of wine will depend on actual consumer demand and market trends. Several also express reservations as to the taste quality of these wines. Finally, some restaurateurs express a lack of knowledge about these grape varieties and a need for support in order to better understand them and contemplate including them on their menus.

Interest in drought-adapted alternative forage plants is growing. What is their potential as catch crops? A study by Agroscope highlights the advantages and limitations of a selection of these crops.

Interest in forage crop species native to tropical, Asian or Mediterranean regions is on the rise as summer droughts become increasingly frequent. These species can maintain growth even during periods of severe water scarcity.

In 2020 Agroscope conducted in Changins (VD) a trial of twenty species on small plots to investigate their performance as summer catch crops. The species tested included C4 plants (green maize, sorghum, foxtail millet, pearl millet, teff) as well as black oat, paddy rice, legumes (annual lucerne, blue lupin, sulla, forage lentil, squarrose clover, cowpea, lablab), guizotia, Tartary buckwheat and camelina. Their growth, yield and forage quality were compared.

Youth development and soil cover

The catch crop trial ran from 6 August to 30 September.  The weather conditions were very favourable (sufficient rainfall and warmth) during the 55-day growing period. Each species was sown in pure seed. The thousand-seed weight of the different species was used to determine their seeding density and depth.

The youth development, soil cover and general impression were evaluated using a visual scoring system. Green maize, sorghum, cowpea and lablab germinated in less than six days, while blue lupin and squarrose clover took more than 15 days. Soil cover 25 days after sowing was poor for several species, especially forage lentil, blue lupin, sulla, annual lucerne and squarrose clover. The general impression, which includes vigour, density and uniformity of vegetation cover, was good for foxtail millet, guizotia, paddy rice, black oat and camelina.

Yield and nutritional value

Dry matter (DM) yields varied substantially depending on the species. Taking advantage of the favourable conditions, green maize recorded the highest yield at more than 63 dt of DM/ha. Multi-cut sorghum produced 44 dt/ha, followed by buckwheat, camelina and foxtail millet (32 to 33 dt/ha). Several species, most notably the legumes, produced low yields of 20 dt/ha. Unfortunately, although the C4 plants produce large quantities of biomass, they provide only moderately digestible, fibrous forage with low energy levels of 5.0 MJ NEL (net energy of lactation) per kg DM. However, the nutritional values of several species such as black oat, sulla, paddy rice, guizotia and buckwheat are promising. The legumes are characterised by high crude protein levels. It should be emphasised that the lablab provided a high yield of quality forage when combined with multi-cut sorghum.

To better exploit the potential of the species tested, it would be interesting to grow them in association with other forage plants whose quality in terms of yield, nutritional value and growth is known.

White clover and smooth-stalked meadow grass make a significant contribution to persistence and grazeability in high-yielding fodder-production mixtures. Based on the 2022 to 2024 variety trials, Agroscope can now recommend two new varieties for each of these species.

White clover (Trifolium repens L.) is the quintessential fodder legume for long-term intensive use. Thanks to its stolons it is hardwearing and ideally suited to grazing. Grass swards with white clover are characterised by better fodder quality and palatability. Since it fixes atmospheric nitrogen, white clover also reduces the need for nitrogen fertilisers. There are white clover varieties that can release large amounts of prussic acid during digestion, which can adversely affect livestock health. Consequently, close attention is paid to this characteristic during variety testing.

Smooth-stalked meadow grass (Poa pratensis L.) is just as suitable for intensive use as white clover. It has rhizomes that form a dense, hardwearing sward, making it likewise suitable for long-term mixtures, especially for pastures. Unfortunately, the slow juvenile development of smooth-stalked meadow grass means that it can only fulful its task in the sward after some time. Both species require high-yielding, competitive and robust varieties with maximum disease resistance if this potential is to be exploited. 

28 varieties field-tested

From 2022 to 2024 at five sites on the Swiss Central Plateau and two at higher altitudes, Agroscope tested the suitability of ten new cultivars and nine recommended varieties of white clover for fodder production under Swiss conditions. With smooth-stalked meadow grass, seven new cultivars and two recommended varieties were tested at four sites on the Swiss Central Plateau and one at higher locations. Juvenile development, yield, vigour, resistance to leaf diseases, winter-hardiness, persistence, and suitability for cultivation at higher altitudes were assessed, as were fodder digestibility in the case of smooth-stalked meadow grass and release of prussic acid in the case of white clover.

Four new recommendations

The white clover varieties ‘Melital’ from Belgium and ‘Minona’, a Swiss-bred variety, are now recommended. Their high yields and outstanding winter-hardiness make them standout choices. In addition, ‘Melital’ impresses with its excellent resistance to leaf diseases, whilst ‘Minona’ stands out for to its juvenile development and suitability for cultivation at higher altitudes. Both varieties are of the small-to-medium-leaved type.

The smooth-stalked meadow grasses ‘Sextonis’ and ‘Sialis’ are two further new recommendations, both Swiss-bred varieties. ‘Sextonis’ stands out for yield, competitive ability and winter-hardiness, ‘Sialis’ for digestibility.  Both varieties also impress with their good resistance to leaf diseases and remarkable persistence. All four new recommendations substantially improve the recommended range.

Struck off the list

The previously recommended white-clover variety ‘Rabbani’ has lost its recommendation due to its unsatisfactory performance. Consequently, it may only be used as a recommended variety until the end of 2027.

Agroscope’s variety recommendations

Agroscope regularly tests different fodder-plant varieties in order to provide the Swiss agricultural sector with the latest reliable variety recommendations. Published every two years, the List of Recommended Varieties of Fodder Plants forms the basis for developing the best seed mixtures, and is an essential guidebook for the Swiss seed sector.

The use of vegetable fibre can reduce plant-protection product residues by up to 80% in white musts, with a more limited effect in red musts.. The method can be applied in cellar, as a complement to the responsible use of products in the vineyard.

The ‘Viticulture and Oenology’ Experimental Station carried out a study evaluating the efficacy of vegetable fibre (VF) and bentonite (B) in reducing plant-protection products (PPPs) in Petite Arvine and Syrah musts. The study was conducted at laboratory and cellar level on the 2022 and 2023 harvests. In the laboratory, the VF achieves a 33 to 96% reduction in residues depending on the molecule, whilst the effect of the bentonite is negligeable. The combination ‘VF + B’ brings no additional improvement. Fermentation kintetics are preserved overall, although a slowdown can be observed with the bentonite.

Confirmed efficacy of vegetable fibre for white musts in cellar

The results for the white musts in 2022 obtained in the cellar show that settling alone reduces residues by around 20%. The addition of VF causes a marked improvement in efficacy (up to 85% for boscalid), enabling the complete elimination of certain molecules (mandipropamid, cyazofamid) with no detectable organoleptic changes. In 2023, the VF completely eliminated all measurable residues. B remains ineffective in all tested conditions (Fig. A).

Reduced efficacy of vegetable fibre for red musts in cellar

With red musts, fermentation reduces residues by 40 to 100%, limiting the impact of the VF. Results vary according to harvest: a modest reduction in 2022 (boscalid) and an absence of effect in 2023. Organoleptic differences and variations in certain parameters (end of malolactic fermentation, anthocyanin content)) were also observed. The application of VF during settling of the white musts is thus effective and can easily be incorporated into the vinification process, particularly during harvests characterised by heavy pressure from pests and late treatments. With red musts, direct use of VF is not recommended; an application on finished, filtered wine is more appropriate. This method represents an additional tool for the sensible management of PPPs at the vine, rather than a replacement for it.

The 451 wines analysed on the VITISWISS national platform for monitoring plant-protection product residues show that Swiss wines possess a high level of quality, with only two cases of non-compliance.

Aiming to enable Swiss producers to guarantee the quality of their wines in terms of plant-protection product residues and research solutions for limiting the presence of residues in wine, VITISWISS – the Swiss federation for the development of a sustainable wine sector – decided in 2019 to set up a national platform to monitor plant-protection product residues in collaboration with institutional and professional partners. Between 2019 and 2021, the platform, which offers a centralised and standardised analysis procedure, dealt with 160 active substances and metabolites comprising 37 herbicides, 50 insecticides and 73 fungicides.

Wines compliant with the legal requirements

Of the total of 451 bottles of wine originating from organic or integrated production (IP) that were analysed, 449 or 99.6% met the legal requirements. Only two wines, i.e. 0.4% of the samples, were declared non-compliant following the identification of two products not authorised for use on grapevine in Switzerland. Overall, 26 other authorised active substances or metabolites were detected at values above the practical quantitation limit (PQL) of 0.01 mg/l. On average, the residue values recorded for these different products were nearly 30 times lower than the legal values. The analyses also identified 19 additional molecules at trace levels below the PQL.

The average number of residues ranged between 1.2 for organic wines and 3.1 for IP wines (Fig. 1). The average values decrease considerably when phosphoric acid and phthalimides whose provenance is not necessarily associated with plant-protection product treatments are left out of the equation, resulting in organic wines with virtually no residues and IP wines with a maximum average of 1.4 residues.

Fungicides: the crux of the issue

The great majority of residues were fungicides or their metabolites. Among the active substances identified are seven anti-botrytis active substances (fenhexamid, boscalid, cyprodinil, fludioxonil, fenpyrazamine, carbendazim and thiophanate-methyl), seven anti-mildew active substances (fosetyl-Al, iprovalicarb, mandipropamid, metalaxyl, dimethomorph, azoxystrobin and ametoctradin) and four anti-powdery-mildew active substances (fenpropidin, fluxapyroxad, fluopyram and spiroxamine). No traces of acaricides were detected in the samples analysed; 98% of the wines contained no traces of insecticides above the PQL and 99.3% contained no herbicide residues.

A survey conducted in the Canton of Vaud on Chasselas reveals frequent nitrogen deficiencies in the vineyard for the 2022-2023 vintage, despite the application of soil supplements. Only a third of those surveyed measure yeast-assimilable nitrogen (YAN) in the must.

In viticulture, vine nitrogen nutrition management makes a crucial contribution to the elaboration of quality grapes and wines. As part of this study, a questionnaire was submitted to winemakers in the Canton of Vaud to gather information on nitrogen nutrition management for the 2022, 2023 and 2024 vintages of the Chasselas grape variety both on the vine and in the cellar.

Nitrogen deficiency symptoms in specific vintages

Nitrogen deficiency symptoms in Chasselas were observed by 56% of survey participants in 2022 and by 50% in 2023 – vintages marked by unusually high sunshine levels and summer temperatures. By contrast, these symptoms were not observed in 2024, a year characterised by numerous rainy episodes (Figure 1).

Soil application is the most widespread approach to nitrogen fertilisation

Concernant la fertilisation azotée au vignoble, les pourcentages varient peu d’un millésime à l’autre. De manière générale, la fertilisation azotée au sol est la pratique la plus répandue chez les vignerons du canton de Vaud (avec des pourcentages compris entre 55 % et 60 % selon les millésimes), tandis que l’apport foliaire est très peu pratiqué. Une tendance similaire a été observée en Regarding nitrogen fertilisation in the vineyard, percentages vary little from one vintage to another. In general, soil application of nitrogen fertiliser is the most widespread practice among winemakers in the Canton of Vaud (with percentages ranging between 55% and 60% according to vintage), whilst foliar application is highly uncommon. A similar trend was observed in Valais, where a survey conducted on the 2022 vintage revealed that 89% of the respondents had not applied foliar nitrogen to the Chasselas grape variety in the vineyard. Nevertheless, foliar fertilisation remains an important practice in viticulture, as it optimises nutrient assimilation to prevent nitrogen deficiencies in grapes without impacting vine vigour. A yeast-assimilable nitrogen (YAN) concentration below 140 mg/L equates to a moderate deficiency situation for the vinification of white-wine musts.

Slowdown at end of alcoholic fermentation and variability of yeasts used

In the cellar, 27% of respondents measured YAN in the Chasselas must in 2022, followed by 33% in 2023 and 2024 (Figure 2A), with YAN values ranging between 62 and 182 mg/L. The majority of producers did not observe a significant slowdown of alcoholic fermentation (AF) (Figure 2B). Nevertheless, some producers reported sluggish or even stuck fermentation at the end of AF, with vats encountering difficulties in finishing the fermentation process. These slowdowns are most likely associated with the presence of residual sugars left by the active dry yeasts (ADY’s) used, which turned out to be a total of 32 different yeast strains. In their choice of yeasts, several participants expressed a preference for low nitrogen requirement (LNR) ADY’s over high nitrogen requirement (HNR) ADY’s. A survey of the yeasts used by producers is underway to evaluate their fermentation efficiency at different levels of assimilable nitrogen. The aim is to create factsheets to propose a microbiological tool that could be used as an alternative to oenological inputs during nitrogen-deficient vintages.

Lastly, temperature control is a practice employed by 42% of respondents to resolve these slowdowns. Ninety-four percent of cellars have a temperature control system. Other practices used are aeration (39%) and the addition of lees or nutrients (19%).

Autumn-sown annual or perennial flower strips support antagonists of aphids, which are vectors of virus yellows, a severe disease in sugar beet. The effectiveness of these strips is influenced by floral composition, sowing time point and surrounding landscape elements.

Biological control aims to reduce pesticide use by increasing populations of natural enemies that target pest species. The effectiveness of flower strips (FS) for this purpose has been demonstrated in different crops. However, in spite of the significant challenge posed by the green peach aphid (Myzus persicae) and the black bean aphid (Aphis fabae), which introduce virus yellows into the fields early in the season, research on the role of FS in sugar-beet crops remains limited.

Agroscope therefore conducted a study to identify the most suitable FS type for supporting biological control in sugar beet. To this end, we quantified flower availability and composition of different FS types in early spring, recorded the abundance and composition of aphid antagonists across different FS types, and analysed the influence of surrounding landscape elements on their presence.

To do this, three FS types were each sown on ten sugar beet fields managed without insecticide. These were compared to sugar beet strips managed with or without insecticide, the latter two treatments serving as controls.

Overwintering flower strips are beneficial for aphid antagonists

Many adult aphid antagonists are dependent on the presence of flowers to maintain their populations. Particularly in the sugar-beet system, early-season flower availability is critical for ensuring that aphid antagonists are present early enough to control pests in a timely manner. Such flowers were abundant in the autumn-sown annual and perennial FS but absent in spring-sown annual FS. Moreover, aphid antagonists were more abundant in the first mentioned FS types than in the spring-sown annual FS and in the controls, demonstrating the link between flower availability and the presence of aphid antagonists.

Different hoverfly communities

Overall, aphid antagonist composition did not differ significantly between the autumn-sown annual and the perennial FS. By contrast, hoverfly communities differed between these two FS, most likely owing to the different composition of the flowering plant species.

Mixed response of aphid antagonists to landscape elements

Forest and flowering elements had no effect on the overall abundance of aphid antagonists. By contrast, a closer look at specific predator groups revealed a positive association between Braconidae and forest cover within a 500m radius, while hoverflies showed a negative association with forest cover at the 2000m scale..

Faced with climate change that undermines the stability of forage production, the introduction of more-drought-tolerant catch crops represents an adaptive strategy with a high likelihood of success in safeguarding livestock feed supplies.

Forage production can be substantially reduced by climate change, particularly due to ever-more-frequent and extreme summer droughts alternating with more intense rains. This situation jeopardises livestock feed supply security and undermines the resilience of Swiss animal husbandry systems. Faced with these challenges, incorporating drought-tolerant catch crops into the rotation appears to be a promising adaptive strategy.

Five drought-adapted catch crops tested

In the Jura region, this study compared a conventional catch crop – oat-forage pea-summer vetch (OPV) – with five other catch crops identified as drought-adapted, within the context of contrasting summer climatic conditions observed in 2021 and 2022: hybrid forage sorghum with annual clovers, Sudan grass, black oat with crimson clover, foxtail millet, and pearl millet.

Dry-matter yield differed between the catch crops tested, although not between years. On average, foxtail millet, hybrid forage sorghum with annual clovers and the OPV recorded the highest dry matter (DM) yield, with values ranging between 26 and 29 dt DM per ha.

The OPV had the highest nitrogenous matter (NM) content (172 g NM / kg DM) as well as the lowest fibre values, on a par with the hybrid forage sorghum with annual clovers. For both these methods, crude protein yields per hectare averaged 430 kg NM, which could help maintain the protein autonomy of the farms.

Hybrid forage sorghum with annual clovers: a viable alternative to OPV

Hybrid forage sorghum in association with annual clovers proved a viable alternative to OPV: well adapted to contrasting climatic conditions, it ensured satisfactory yields as well as satisfactory forage quality, thanks to hybrid forage sorghum’s drought tolerance and the complementarity of its growth with that of annual clovers. By contrast, the yields and forage quality of the catch crops based on black oat, Sudan grass and pearl millet were unsatisfactory within the context of this trial.