ABSTRACT Introduction Environmental stressors on the agricultural field are increasing, from global warming to the rise of the human population. Among the resulting challenges, plant diseases remain one of the most important causes of crop losses worldwide. Chemical pesticides are used to protect crops, yet they often come with significant environmental risks to the farmers, water, pollinators, and soil diversity. It is crucial, therefore, to investigate non‐chemical alternatives to protect crops. Nevertheless, their effectiveness often varies and is difficult to predict, as results obtained under laboratory conditions rarely translate to the complex and dynamic environments of agricultural fields. Materials and Methods In this 3‐year on‐farm study, we compared the effects of chemical and alternative seed treatments (Thermoseed, electron beam, and mustard‐based treatments) on agronomic parameters (yield, protein, thousand grain weight, and micronutrients) as well as on the bacterial and fungal microbial communities associated with winter wheat. Results Neither the chemical nor the alternative seed treatments affected any of the agronomic parameters measured. The treatments had no effect on the microbial community. Because the seeds used had a low disease prevalence, it was not possible to assess the intrinsic efficacy of the alternative treatments. Conclusions The alternative treatments showed no evidence of phytotoxicity in our on‐farm field study, indicating their suitability for further evaluation. However, none of the treatments, including the synthetic treatment, had a positive effect when seeds carried a low pathogen load. Our results suggest that pesticide applications on seeds with low levels of seedborne pathogens may be unnecessary, unless soilborne pathogens are suspected to be present.

Understanding how different tillage practices affect crop productivity and soil fertility is essential for developing sustainable agriculture systems. Here we investigated how no-till affected winter wheat yield and soil fertility after 13 years since its introduction in a clay and a loam soil compared to conventional ploughing, shallow tillage and minimum tillage. During the study period 2007-2020 the annual yield of winter wheat did not differ significantly among the four tillage treatments. However, the no-till showed the lowest relative annual yield and the largest yield variability. The quality of winter wheat grains was affected primarily by the soil texture than by the tillage treatment. A significant effect of tillage on the stocks of soil organic carbon, total nitrogen and exchangeable potassium and magnesium was observed only in the topmost 10-cm, where larger values were found for the three non-inversion tillage treatments. However, when the entire 50-cm deep soil profiles were evaluated, only non-significant differences in nutrient stocks were detected between tillage treatments. We observed a clear stratification of microbial biomass carbon along the soil profile with larger values in the topmost soil layers in the no-till and the non-inversion minimum tillage. Overall, our data indicate that even if the no-till may still be in a transition phase in terms of crop yield, its positive effects on soil organic carbon and microbial biomass are observable after 13 years. In addition, we underline as the minimum tillage appears, at least under the local conditions, as a very suitable practice providing multiple agronomic and environmental advantages.

Ramial wood chips (RWC) amendment has great potential in sustainable agriculture; however more data is needed to assess its effect on soil fertility and carbon (C) storage. In this study, we investigated the effect of a single application of RWC amendment on a silty clay loam soil. During the 5 year experiment, we measured biomass production, grain yields and crop nutrient uptake. At the end of the experiment, we measured soil micro-and macronutrients, soil organic C (SOC) content and thermal stability, microbial biomass C (Cmic), and organic C and total N contents in soil particle size fractions. Soil physical properties, including structural porosity, air and water capacity, were also measured. Neither crop biomass production nor grain yields were affected by RWC. However, RWC was found to affect nutrient uptake, with improved N, P and Mg uptakes for the 2nd and 3rd crops after RWC amendment, and decreased Mn, Fe and Zn uptakes in the second half of the study period. The initially low SOC content increased by 10%, mainly in the mineral-associated organic matter fraction, resulting in a higher SOC stability. The increase in SOC following RWC amendment decreased the bulk density and increased the easily available water capacity due to a larger structural porosity. The increased porosity in the 15-30 mu m diameter range was ascribed to a change in SOC quality. In conclusion, RWC amendment improved macronutrient uptake in the short term, but decreased micronutrient uptake in the medium term. RWC increased SOC content and positively affected SOC quality, thus improving soil physical properties including water capacity and aeration. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

One of the critical challenges in agriculture is enhancing yield without compromising its foundation, a healthy environment and, particularly, soils. Hence, there is an urgent need to identify management practices that simultaneously support soil health and production and help achieve environmentally sound production systems. To investigate how management influences production and soil health under realistic agronomic conditions, we conducted an on‐farm study involving 60 wheat fields managed conventionally, under no‐till or organically. We assessed 68 variables defining management, production and soil health properties. We examined how management systems and individual practices describing crop diversification, fertiliser inputs, agrochemical use and soil disturbance influenced production—quantity and quality—and soil health focusing on aspects ranging from soil organic matter over soil structure to microbial abundance and diversity. Our on‐farm comparison showed marked differences between soil health and production in the current system: organic management resulted in the best overall soil health (+47%) but the most significant yield gap (−34%) compared to conventional management. No‐till systems were generally intermediate, exhibiting a smaller yield gap (−17%) and only a marginally improved level of soil health (+5%) compared to conventional management. Yet, the overlap between management systems in production and soil health properties was considerably large. Our results further highlight the importance of soil health for productivity by revealing positive associations between crop yield and soil health properties, particularly under conventional management, whereas factors such as weed pressure were more dominant in organic systems. None of the three systems showed advantages in supporting production‐soil health‐based multifunctionality. In contrast, a cross‐system analysis suggests that multifunctional agroecosystems could be achieved through a combination of crop diversification and organic amendments with effective crop protection. Synthesis and applications : Our on‐farm study implies that current trade‐offs in managing production and soil health could be overcome through more balanced systems incorporating conventional and alternative approaches. Such multifunctionality supporting systems could unlock synergies between vital ecosystem services and help achieve productive yet environmentally sound agriculture supported by healthy soils.

Both soil quality degradation and climate change mitigation issues emphasize the need to increase, or at least stabilize, the topsoil organic carbon content (wt%) in arable land. This on-farm study aimed at measuring the impact of agricultural practices on changes in soil organic carbon (SOC) content over 10 years. A total of 120 fields belonging to 120 farms representative of the cropping systems and soil properties in Western Switzerland (Lake Geneva region) was randomly selected. The field 0–20 cm topsoil was sampled at a 10-years interval, and the corresponding cropping practices were gathered using farmer’s interviews and the mandatory records of yearly practices at field level in Swiss-farms. Only 1) organic matter inputs and 2) cover-crop intensity were significantly correlated to SOC increase while 3) the soil tillage intensity and 4) the soil saturation in carbon expressed as a SOC to clay content ratio were correlated to SOC decrease. Among others, temporary meadows were not correlated to changes in SOC content mainly due to increased tillage and decreased cover-crops between meadows. Organic farming did not correlate either with SOC changes due to the large tillage intensity applied for weed control. The observed SOC content changes ranged from −56‰ to +74‰ and were well explained by a linear regression model with additive effect of the four identified SOC change factors. The additivity of these factors means that farmers can emphasize the methods of their choice when regenerating their soils. This study advocates that strict no-till is not required at low carbon saturation level (small SOC:Clay ratio). However, as carbon saturation increases, conservation tillage and then no-till practices become necessary to further increase SOC contents. These findings are in accordance with previous studies showing that since 2015 SOC is increasing at more than +4‰ on average in the region and provide practical insights to further manage the transition of farming systems towards soil regeneration.

The degradation of soil from agricultural land is a major threat to food security and a driver of global changes. Soil conservation systems are thus being promoted and/or adopted worldwide. In this on-farm study conducted in Switzerland, we compared the effect of three cropping systems - conventional with tillage, conventional without tillage (i.e. no-till) and organic farming with tillage - on soil quality. Samples from 60 winter wheat fields belonging to these three systems were analysed for soil carbon concentration, soil aggregate distribution and soil biological properties (microbial carbon and mycorrhizal biomarkers), at three different depths (0-5 cm, 5-20 cm and 20-50 cm). Information about cropping practices was collected through surveys. The main differences in soil properties between systems occurred for the surface layer (0-5 cm depth), with increased soil organic carbon concentration and stock under no-till compared to the conventionally tilled fields. No-till and organic fields showed a higher mean aggregate size and proportion of macroaggregates in the surface layer compared to tilled conventional fields, with a greater amount of carbon in the large macroaggregates. However, large within-system variability was also observed, which tended to override differences between systems. Across systems, clay content, microbial carbon, and the mycorrhizal PFLA biomarkers were the major drivers of soil organic carbon concentration, clay to carbon ratio and carbon accumulation in the large macroaggregate fraction. Aggregation at 0-5 cm was mostly related to tillage depth, while climate variables and especially clay content played a major role for deeper layers. Our results demonstrate that within the constraints set by soil texture and climate, organic agriculture and no-till can contribute to improved soil carbon and aggregation properties. Thus, we advocate for the identification of the main drivers of soil quality in order to inform management and improve soil functioning in agricultural fields in the long term.

Pesticides are applied in large quantities to agroecosystems worldwide. To date, few studies assessed the occurrence of pesticides in organically managed agricultural soils, and it is unresolved whether these pesticide residues affect soil life. We screened 100 fields under organic and conventional management with an analytical method containing 46 pesticides (16 herbicides, 8 herbicide transformation products, 17 fungicides, seven insecticides). Pesticides were found in all sites, including 40 organic fields. The number of pesticide residues was two times and the concentration nine times higher in conventional compared to organic fields. Pesticide number and concentrations significantly decreased with the duration of organic management. Even after 20 years of organic agriculture, up to 16 different pesticide residues were present. Microbial biomass and specifically the abundance of arbuscular mycorrhizal fungi, a widespread group of beneficial plant symbionts, were significantly negatively linked to the amount of pesticide residues in soil. This indicates that pesticide residues, in addition to abiotic factors such as pH, are a key factor determining microbial soil life in agroecosystems. This comprehensive study demonstrates that pesticides are a hidden reality in agricultural soils, and our results suggest that they have harmful effects on beneficial soil life.

En bio, la diversite des cultures de la rotation joue un role essentiel. Pour accompagner le developpement de nouvelles cultures ou varietes, le FiBL met en place des dispositifs experimentaux. Tour d’horizon des essais 2020.

Organic Soybean cultivation experiences an upscale at the moment in Switzerland. As in the rest of Europe, Switzerland is still heavily dependent on protein imports. After years of stakeholders efforts of the development of a value chain for organic soybeans for human nutrition, various attempts to develop the soybean cultivation for feed proved to be fruitful despite the fact that Swiss price level is beyond competition for world market prices. The organic farmers themselves decided to become, at least partially, more independent from overseas soybean imports by opting for organic soybeans of European origin since 2019. Furthermore, Bio Suisse decided that from 2022 on, all ruminants under Bio Suisse certification must be fed with feed of Swiss origin, concentrates are limited to 5% of the ration. Since many years numerous projects are carried out to increase the domestic protein production by developing suitable production systems for peas, faba beans, lupines and soybeans with stakholders along the value chain. Since more than 30 years, Swiss breeders successfully develop 00 to 000 soybean varieties with a focus on human nutrition, organic soybean cultivation and the respective value chains from breeding to endproduct is developing strongly. This article will shed light on particular aspects and drivers, specific measures, relevant projects and cultivation techniques of organic soybean production in Switzerland in the past years and will give an outlook on the future of organic soybeans.

Identifying opportunities and limitations for closing yield gaps is essential for setting right the efforts dedicated to improve germplasm and agronomic practices. This study analyses genotypes × environments interaction (G × E), genetic progress, and grain yield stability under contrasting production systems. For this, we analyzed datasets obtained from three Swiss trial-networks of winter wheat that were designed to evaluate genotypes under organic farming conditions, conventional management with low-inputs (150 kg nitrogen (N) ha−1 with no fungicide application) and conventional management with high-inputs (170 kg N ha−1 with fungicide application). The datasets covered the periods from 1998 to 2018 for organic and conventional management with low-inputs and from 2008 to 2018 for conventional management with high-inputs. The trial-networks evaluated each year an average of 36 winter wheat genotypes that included released varieties, advanced breeding lines, and lines for registration and post-registration in Switzerland. We investigated within each trial-network the influence of years, genotypes, environments and their interactions on the total variance in grain yield and grain N concentration using variance components analyses. We further applied mixed models with regression features to dissect genetic components due to breeding efforts from non-genetic components. The genotype as a single factor or as a factor interacting with the environment or the year (G × E, G × year, and G × E × year) explained 13% (organic), 20% (conventional low-inputs), and 24% (conventional high-inputs) of the variance in grain yield, while the corresponding values for grain N concentration were 29%, 25%, and 32%. Grain yield has stagnated since 1990 for conventional systems while the trend under organic management was slightly negative. The dissection of a genetic component from the grain yield trends under conventional management showed that genetic improvements contributed with 0.58 and 0.68 t ha−1 y−1 with low- and high- inputs, respectively. In contrast, a significant genetic source in the grain yield trend under organic management was not detected. Therefore, breeding efforts have been less effective on the wheat productivity for organic farming conditions than for conventional ones.

Rapeseed is a major oilseed crop in Europe, whose development has been a roller coaster ride over the last 20 years. In a context of increasing demand for organic products, this crop must however face numerous constraints concerning its demanding place in the rotation, a choice of varieties limited to line varieties at least in the Switzerland, a crucial implantation which must cope with variable water stress during sowing and winters with less and less frost, very demanding nitrogen nutrition requirements in the context of organic farming, and particularly harmful pests. A consolidation of the research devoted to rapeseed cultivation, but also a redesign of its cropping system and economic considerations should make it possible to better position this crop in relation to agri-environmental contexts, but also in relation to the complementary aptitudes of other oilseed crops.

To better understand the ability of cover crops to control weeds in a maize crop (Zea mays, L.) grown with reduced tillage, four field experiments were set up from 2009 to 2014 in the western part of Switzerland. Ten non-wintering cover crop species were compared to a no cover crop control in strip plot experiments including different weeding strategies. The weeding strategies included no or minimum tillage before maize seeding. Soil coverage by weeds at early maize stage (2-4 leaf stage) varied drastically between weeding strategies and years. In most cases, cover crops allowed to reduce the weed pressure compared to the no cover crop control. The most efficient cover crop species varied from year to year, but niger (Guizotia abyssinica, (L.f.) Cass.), sunflower (Helianthus annuus, L.), field pea (Piston sativum, L.) and phacelia (Phacelia tanacetifolia, Benth.) gave the best overall results. Maize yield differed significantly between weeding strategies only one year, with higher yield observed with minimum tillage. In some situation, cover crops cultivated in autumn still showed a significant impact on maize yield, with common vetch (Vicia saliva, L.) as the most successful species. Interestingly, the effect of cover crop on weed cover and maize yield was not limited to the less intense strategy (no tillage). These results show that cultivating cover crops before maize in this type of conditions is a promising method to help controlling weeds. In addition, cover crops are known for providing multiple ecosystem services which could altogether improve the sustainability of cropping systems on the long term.

Thanks to positive interactions between species, growing mixtures of cover crops allows improving the ecosystem services provided by cover crop cultivation. In this study, the influence of species diversity but also of species identity and mixture composition on cover crop biomass production and its stability in diverse growing conditions was studied. Several field experiments (varying soil type, preceding crop, soil tillage, sowing density, nitrogen fertilization and spatial replication) were set up in Switzerland during the period 2013-2016. In these experiments, the performance of cover crop species grown as sole crops was compared to that of multispecific mixtures. Part of these experiments followed a simplex design in which four cover crop species were combined together with different proportions, producing a total of 25 mixtures of varied diversity. The other experiments compared sole crop and mixture biomass production in standard randomised block or split plot experiments. Globally, mixtures tended to produce slightly more biomass than the sole crops, with an average between 2 t/ha and 3.2 t/ha for sole crops and of about 3.5 t/ha for mixtures. Overyielding as well as transgressive overyielding were observed, in 81% and 37% of the cases on average, respectively. However no effect of the level of species diversity within mixtures could be found. Biomass production of cover crops was highly influenced by their growing conditions and by the identity of the species involved, especially for sole crops and bispecific mixtures. The analyses of the simplex experiments allowed to show that species interactions played an important role in biomass production in 7 out of 15 growing conditions, even for a short growing period of about three months. Most of the cover crop mixtures with the highest biomass production had a rather low diversity, i.e. about two species on average, but the identity of the species involved in these mixtures depended on the growing conditions. Our results do not show a strong diversity effect on the biomass production of cover crop mixtures cultivated for a short growing period, but a stronger effect of species identity and of the growing conditions. Mixtures with low diversity generally outcompete more diverse mixtures, but more diverse mixtures offer an insurance effect given the unpredictability of growing conditions during cover crop cultivation.

Arable soils may act as a sink in the global carbon cycle, but the prediction of their potential for carbon sequestration remains challenging. Amongst other factors, soil aeration is known to influence root growth and microbial activity and thus inputs and decomposition of soil organic carbon. However, the influence of soil aeration on soil organic carbon content has been explored only little, especially at the farm level. Here, we investigated relationships between gas transport properties and organic carbon content in the topsoil and subsoil of 30 fields of individual farms, covering a wide range of textural composition. The fields were managed either conventionally, organically, or according to no-till practice. Despite considerable overlap between the management systems, we found that tillage increased soil gas transport capability in the topsoil, while organic farming resulted in higher soil organic carbon content. Remarkably, higher gas transport capability was associated with higher soil organic carbon content, both in the topsoil and subsoil (0.53 < R-2 < 0.71). Exogenous organic carbon inputs in the form of crop residues and organic amendments, in contrast, were not related to soil organic carbon content. Based on this, we conjecture that higher gas transport capability resulted in improved conditions for root growth, which eventually led to increased input of soil organic carbon. Our findings show the importance of soil aeration for carbon storage in soil and highlight the need to consider aeration in the evaluation of carbon sequestration strategies in cropping systems.

Root-associated microbes play a key role in plant performance and productivity, making them important players in agroecosystems. So far, very few studies have assessed the impact of different farming systems on the root microbiota and it is still unclear whether agricultural intensification influences the structure and complexity of microbial communities. We investigated the impact of conventional, no-till, and organic farming on wheat root fungal communities using PacBio SMRT sequencing on samples collected from 60 farmlands in Switzerland. Organic farming harbored a much more complex fungal network with significantly higher connectivity than conventional and no-till farming systems. The abundance of keystone taxa was the highest under organic farming where agricultural intensification was the lowest. We also found a strong negative association ( R 2 = 0.366; P < 0.0001) between agricultural intensification and root fungal network connectivity. The occurrence of keystone taxa was best explained by soil phosphorus levels, bulk density, pH, and mycorrhizal colonization. The majority of keystone taxa are known to form arbuscular mycorrhizal associations with plants and belong to the orders Glomerales , Paraglomerales , and Diversisporales . Supporting this, the abundance of mycorrhizal fungi in roots and soils was also significantly higher under organic farming. To our knowledge, this is the first study to report mycorrhizal keystone taxa for agroecosystems, and we demonstrate that agricultural intensification reduces network complexity and the abundance of keystone taxa in the root microbiome.

To compare different cropping systems, it is crucial to describe explicitly the associated cropping practices. A set of 31 indicators and six composite indexes addressing farm structure, crop diversification, soil disturbance, organic matter inputs, nitrogen fertilisation, crop protection, and yield was used to describe 59 winter wheat fields belonging to conventional, no-till and organic systems, in Switzerland. The aim of this study was to investigate the complementarity and redundancy of the indicators and their potential to characterise these cropping systems. In general, weak correlations were observed between the studied indicators, showing the importance of using a set of indicators to fully characterise cropping practices. The complex indicators were often correlated with simpler ones, but it cannot be excluded that they can prove to be more useful in different contexts. Retaining a combination of simple and complex indicators to obtain a broad picture of cropping practices is thus recommended. The indicators highlighted differences but also similarities between the three systems. For example, the input of organic matter and crop rotation diversification were similar between the three systems. In contrast, total nitrogen fertilisation (lower for organic systems) and soil disturbance (lower for no-till systems) were different. A high within-system variability was observed for some indicators, suggesting that using quantitative indicators rather than simple classifications based on a general description of the systems allows a better characterisation of these systems. Overall, the use of indicators has the potential to improve our understanding of the influence of cropping practices on the soil and environment.

One of the primary challenges of our time is develop sustainable farming systems that can feed the world with minimal environmental impact. Some studies argue that organic farming systems are best because these have minimal impact on the environment and are positive for biodiversity. Others argue that no-tillage systems are better because such systems save energy and preserve soil structure and quality. A third group argues that conventional farming systems are best because yield per hectare is highest. However, so far, systematic comparisons of major arable production systems are rare and often it is difficult to compare the advantages and disadvantages of farming systems in a systematic way due to differences in soil/site characteristics and management. Here we present data of the Swiss Farming Systems and Tillage Experiment (FAST), a long term experiment where the main European arable production systems (organic and conventional farming, reduced tillage and no tillage, each system with different cover crop treatments) are being compared using a factorial replicated design. A multidisciplinary team of researchers from various disciplines and organizations analysed this experiment. We show the advantages and disadvantages of the various production systems and present data on plant yield, life cycle analysis, global warming potential, soil quality, plant root microbiomes and above and below ground biodiversity. Our results demonstrate that: i) plant yield was highest in the conventional systems, ii) soil biodiversity and above ground diversity tended to be higher in organic production systems, iii) soil erosion was lowest in the absence of tillage and in organic production systems, iv) the positive effects of cover crops were highest in organic production systems and increased with reduced land use intensity, v) the global warming potential of organic farming systems was lower compared to conventional systems, and vi) root and plant microbiome varied between the farming systems with the occurrence of indicator species that were specific for individual farming practices. In a next step we compared the results of this experiment with observations from a large farmers network (60 fields) in Switzerland (see abstract by Buchi et al.) where organic, conventional and conservation agriculture were compared. The results of our trial (e.g. yield and environmental performance of the different farming systems) were largely in agreement with those observed in the farmers network. Overall, our results indicate that no farming system is best and the choice of the “best” production system depends on economic, ecological and environmental priorities.

Currently, in the context of agriculture, cover crops are crops cultivated with the sole aim of providing important ecosystem services such as erosion prevention. Many services offered by these crops are directly linked to the development of their vegetation, and especially of canopy cover. A proper estimation of this cover is thus necessary to evaluate cover crop performance. Many methods to estimate canopy cover exist, but differ in terms of effort and time needed to implement them. In this study, we compared visual assessment of canopy cover in the field with two methods of digital image analysis (Assess and Canopeo), for different cover crop species and vegetation types. Visual estimation was positively correlated with both type of image analysis estimations. However, it showed systematically lower values of canopy cover, especially at intermediate canopy cover values. The type of vegetation influenced the visual and digital image estimations, narrow leaf species being the most difficult to evaluate visually. This study showed that depending on its utilization, visual canopy cover assessment could be useful, especially when only relative estimation of canopy cover is needed. When absolute canopy cover estimation is needed, the use of digital image analysis should be preferred.