Plant and Soil

Carbon farming practices are increasingly adopted as part of regenerative agriculture to enhance soil carbon sequestration and improve agricultural sustainability. However, their effects on the phyllosphere microbiome, and how these interact with field biodiversity, remain poorly understood. We investigated how field biodiversity and carbon farming practices (cover crops, all-in mixes, adaptive grazing and ley mixture) influence leaf microbial communities across 19 Finnish farms using ITS and 16S amplicon sequencing. Foliar fungal - but not bacterial - diversity increased with plant species richness. Carbon farming altered both fungal and bacterial community composition, but only fungal community was positively associated with disease load. Network analysis identified three candidate keystone taxa: Alternaria sp. (FASV 34) and Sporobolomyces roseus (FASV 2070), which were mutually exclusive, and Methylobacterium sp. (BASV 75), which co-occurred with FASV 2070. Together, these findings demonstrate that different carbon farming practices shape distinct leaf microbiomes cover crop systems tending to favor potential fungal pathogens, whereas ley mixture and adaptive grazing strategies promote microbial taxa associated with healthier phyllosphere communities. Our study underscores the importance of understanding the complex microbial interactions within leaf ecosystems to inform sustainable agricultural practices.

Aims Although ammonia-oxidising archaea (AOA) dominate nitrifier communities in many agricultural soils, the contribution of the less abundant ammonia-oxidising bacteria (AOB) to nitrogen oxide emissions, particularly nitric oxide, remains poorly understood. This study investigated the roles of AOA and AOB in regulating nitric oxide (NO) and nitrous oxide (N2O) emissions from a urea-fertilised grassland soil and evaluated the nitrification inhibitors dicyandiamide (DCD) and 3,4-dimethylpyrazole phosphate (DMPP). Methods A 28-day soil incubation experiment was conducted using a denitrification incubation system to continuously monitor NO and N2O emissions. In parallel, a destructive incubation experiment was performed to determine the dynamics of ammonium (NH-N) and total oxidised nitrogen (TOxN) and to assess changes in the abundance of AOA and AOB following urea application with or without DCD or DMPP. Results AOA accounted for approximately 66% of the total ammonia-oxidising community. Neither inhibitor significantly affected AOA abundance, whereas both suppressed AOB, with DMPP showing stronger and more persistent inhibition than DCD. DMPP reduced NO emissions by 16 to 75%, whereas N2O emissions decreased by only 0.2 to 27%. The greater reduction in NO, together with the preferential suppression of AOB, suggests that low-abundance AOB contributed disproportionately to NO production despite the numerical dominance of AOA. Conclusions These findings suggest that AOB can contribute disproportionately to NO emissions despite their lower abundance relative to AOA. The preferential suppression of AOB by DMPP was associated with a substantial reduction in NO emissions, highlighting AOB-associated processes as a potential target for mitigating reactive N losses from fertilised soils.

Globally, contaminated soils pose serious risks to agriculture, biodiversity of ecosystems, and human health. Although a variety of monitoring and remediation methods have been developed over the years, there remains a lack of theoretical modelling to better understand the impact of contamination on soil carbon in a microbially-mediated system. In this study, we develop a model which incorporates contaminated soil organic carbon, uncontaminated soil organic carbon, dissolved organic carbon, microbes, extracellular enzymes, and CO2, to explore how different amounts of contamination and modes of contamination (pulse and press) affect microbially-mediated carbon flux within both vegetated and barren environments. The model represents contamination as a pool of contaminated soil organic carbon that is more resistant to microbial degradation than uncontaminated soil organic carbon. The results show that, in barren environments, the amount and type of contamination has no notable impact on the soil system. In contrast to this, in vegetated environments, plants mitigate the impact of large contamination inputs with differences in outcome depending on the amount and type of contamination.

Drought and waterlogging are prominent climate change challenges that, alone or in sequence, pronouncedly constrain agricultural crop production. A better understanding of relationships between water availability and nutrition regarding plant functioning is needed to optimise fertilisation under these challenges. We investigated impacts of drought, waterlogging and drought followed by waterlogging under two fertilisation regimes (low, normal) on various traits of wheat (Triticum aestivum). Next to biomass and photosynthesis measurements, cross-platform metabolomics was applied for in-depth metabolic analyses of flag leaves. We found detrimental effects of drought and drought-waterlogging on shoot and root biomass, especially at normal fertilisation, while photosynthetic traits were not or only slightly affected. Foliar nitrogen contents were higher in plants exposed to drought or to drought-waterlogging. Numerous primary and specialised metabolites were modulated by fertilisation and/ or watering. In particular, amino acids, benzoxazinoids and flavonoids were affected by fertilisation. Due to watering especially several amino acids changed in concentrations, with the induction pattern partly depending on fertilisation. Our study deepens the understanding of the interplay between water and nutrient availabilities as well as nutritional demands, growth and metabolism of wheat. This is highly relevant to balance sustainable agricultural nutrient management under the challenges of ongoing climate change.

1. Plant roots employ multiple strategies to acquire soil resources, including the outgrowth of root hairs and the association with arbuscular mycorrhizal fungi (AMF). These structures represent alternative pathways to access soil resources. Evidence is derived mostly from studies within single species or multi-species experiments under controlled conditions. It remains unclear whether this trade-off holds under natural conditions and whether it manifests consistently across different scales of biological organization. 2. We analysed 81 grassland species representing grasses, forbs and legumes, sampled under heterogeneous field conditions in three regions across Germany, allowing for analyses (i) across different species (interspecific), (ii) across communities (intercommunity), (iii) within plant species (intraspecific) and (iv) within root systems of individual plants (intra-individual). Fine root traits related to AMF colonization (including scoring of fungal hyphae and arbuscules) and root hair growth (including length and incidence) were quantified. 3. Comparing plant species, we observed a strong negative correlation between mycorrhizal colonization and root hair traits, confirming previous studies working under controlled conditions. The negative relationship between root hair length and mycorrhization was also evident when comparing mean trait values at the plant community scale. Among different individuals of the same species (i.e. intraspecific scale), there was no consistent pattern of trait-trait relationship. When comparing within roots of the same plant (i.e. intra-individual scale), co-occurrence of root hairs and mycorrhiza was less likely than what would be expected by chance, with forbs showing the most consistent negative pattern. 4. Our study demonstrates that the hypothesized trade-off between AMF and root hairs is a robust pattern under field conditions at the community and interspecific scale. At the intraspecific scale, no uniform trade-off pattern can be discerned, and within single root systems the negative trade-off pattern is widespread but weak. This indicates that ecological and evolutionary constraints shape trait-trait relationships at higher scale, whereas physiological limits do not restrict trait co-occurrence at lower scales.

Background and aims: Perennial root systems develop over decades and exhibit continuous turnover of structural and absorptive components, yet most root architecture models treat woody roots as permanent and neglect root age structure. We developed an empirically constrained modelling framework that explicitly represents age-structured demography, growth regulation and dormancy in perennial root systems. Methods: We extended the functional-structural plant model CPlantBox to simulate perennial root development over decades by integrating age-dependent survival, secondary radial growth and climate-driven dormancy. The model was parameterised using unique three-dimensional root system data from young and mature grapevines, together with dendrochronological root age measurements, and coupled to root hydraulic properties. Key results: Empirical analyses revealed multi-cohort age distributions and substantial turnover of lignified structural roots, contradicting the assumption of a static woody scaffold. The model reproduced age distributions, order-specific survival probabilities and fine-to-structural root length ratios, and generated realistic, genotype-specific three-dimensional architectures. Simulated uptake profiles and hydraulic scenarios showed strong age- and architecture-driven effects. Conclusions: Explicitly representing woody root age distributions and age-dependent processes may fundamentally change predictions of perennial root system architecture and function. The framework advances root modelling beyond annual paradigms and provides a transferable tool for analysing long-term architectural and hydraulic consequences of genotype x climate interactions in perennial crops.

Synthetic nitrogen fertilizers enhance maize (Zea mays ssp. mays) productivity but impose substantial environmental and economic costs. Some Mexican maize landraces support biological nitrogen fixation (BNF) in aerial root mucilage, raising the question of how much variation exists in this trait and how domestication, geographic spread, and improvement have shaped BNF-related traits across Zea in the Americas. We evaluated aerial root traits and BNF capacity across the maize domestication continuum using 60 Zea accessions grown in field experiments over two years under low-N conditions. Some accessions of wild Zea, landraces from Mexico and South America, and improved varieties had elevated nitrogen derived from the atmosphere (%Ndfa), ranging from 20 to 40%; some of these also had greater %Ndfa than typical improved varieties. Spread and improvement appear to have significantly reduced the number of aerial root-bearing nodes, with wild Zea and Mexican landraces consistently producing more. Nevertheless, the proportion of nitrogen derived from the atmosphere (%Ndfa) does not vary systematically across the domestication continuum. Thus, crop evolution shaped aerial root phenotypes more than associative BNF capacity. The persistence of substantial within-group variation indicates that the genetic potential for enhanced BNF remains within the Zea gene pool, providing opportunities to encourage and improve nitrogen use efficiency in maize cropping systems.

Soil nematodes play key roles in regulating organic matter decomposition, nutrient cycling and trophic interactions in the soil ecosystem, and are very useful bioindicators of soil condition and soil health. But to characterise them, we need reliable measurements of nematode biodiversity in soils. DNA-based techniques such as metabarcoding have recently explored their biodiversity, with successful results. However, there are many methodological steps that can modify the outcome considerably and require informed decisions. In this study, we tested the effect on nematode alpha and beta diversity metrics of three methodological steps, namely i) type of extraction of genetic material from the matrix, either from soil directly with different starting amount of material or extracting nematodes first via the Baermann or Oostenbrink methods, ii) the choice of taxonomically-relevant DNA segment for amplification, with a nematode specific primer (NemF/18Sr2b) and a universal eukaryotic primer (3NDf/1132rmod), both within 18S rDNA, and iii) the selection of appropriate reference library for taxonomic assignment (comparing three nematode specialised databases and three broad taxonomic databases). Observed differences in alpha diversity were more pronounced when comparing the nematode extraction vs soil extractions. In particular, direct soil extractions co-extracted many non-nematode taxa, especially if amplified with a universal primer, which can significantly reduce the number of nematode reads obtained and therefore the accuracy of nematode community indexes and other nematode-based metrics. The choice of the reference database strongly affected the taxonomic identification, which calls for extreme caution when making this selection. Notably, specialised databases tended to over assign reads to nematodes that were detected as non-nematodes by broad taxonomic databases. However, beta diversity metrics were consistent across methods, highlighting these metrics as robust against methodological choices. Our study clearly demonstrates that the choices of methods for nematode biodiversity studies using molecular tools can have a big impact on the results, and decisions should be made consciously and carefully.

Background and aims Alpine ecosystems are highly sensitive to climate change, with rising temperatures threatening ecosystem structure and function. This study examined the short-term responses of alpine grassland ecosystems (Mont Blanc, Italy) to projected climate scenarios using an Ecotron mesocosm experiment. Methods Ecosystem monoliths were exposed to current (~420 ppm CO2) and future CO2; concentrations (~550 and ~800 ppm) under RCP 4.5 and RCP 8.5 scenarios, incorporating changes in temperature, precipitation, humidity, and radiation. CO2; fluxes (NEP, GPP, Reco), soil chemistry, vegetation coverage, above- and belowground biomass, and plant functional traits were assessed throughout the experiment. Results Alpine grassland ecosystems withstood moderate warming (RCP 4.5), while under severe warming (RCP 8.5), GPP, vegetation cover and biomass increased with a shift toward aboveground allocation, although daytime NEP remained stable as gains were offset by higher Reco, with no detectable water and nutrients limitations. On a diel basis, higher GPP was offset by enhanced Reco, indicating a potential towards net C loss. Salix herbacea exhibited functional trait adjustments-higher LMA and Na, and elevated delta15N-reflecting greater leaf longevity, water-use efficiency, and altered nitrogen metabolism, suggesting potential community reorganization. Conclusion Over a single growing season, alpine ecosystems appeared relatively stable under moderate warming. However, under the more severe RCP 8.5 scenario, biomass allocation shifted toward greater aboveground and reduced belowground investment, leading to altered C fluxes that, if sustained over the long-term, could drive the ecosystem C balance from a sink to a source. Responses were plant species-specific, indicating uneven acclimation within the community.

Palm oil is the worlds leading vegetable oil, with production continuing to expand, particularly across Southeast Asia. Within established plantations, conserving and restoring riparian margins can reduce erosion, improve connectivity, and support biodiversity. Simultaneously, climate change is increasing thermal stress within tropical agricultural landscapes, raising the potential importance of riparian buffers as microclimatic refugia, although this has not previously been evaluated. The Riparian Ecosystem Restoration in Tropical Agriculture (RERTA) Project is a long-term Before-After Control-Impact experiment established within oil palm plantations in Riau, Indonesia, to evaluate alternative riparian restoration strategies following plantation replanting. Treatments included passive restoration (retaining mature oil palms and allowing natural regeneration), active restoration (enrichment planting with six native tree species), and a control (replanting immature oil palms to the river edge). Six years after restoration, we assessed vegetation structure using terrestrial laser scanning and thermal stability using temperature loggers and thermal imaging. We also evaluated the long-term temperature buffering capacity of each treatment under current and projected climates using CHELSA climate data and downscaled outputs from multiple General Circulation Models under Shared Socioeconomic Pathway scenarios for 2045 and 2085. Active restoration produced greater structural complexity, a more closed canopy, and cooler, more thermally stable conditions than passive restoration and control treatments. Restored margins also contained significantly more cool surface microhabitats, reducing thermal extremes under both current and future climate scenarios. Our findings demonstrate that active restoration of riparian margins can enhance thermal buffering and create microclimatic refugia for biodiversity within tropical oil palm landscapes. As agricultural intensification and climate change continue to reshape tropical ecosystems, restoring structurally complex riparian vegetation will be critical for sustaining biodiversity and the ecosystem services upon which agricultural production depends.

Much of the persistent soil organic carbon (SOC) pool is microbial in origin: microorganisms process plant carbon into biomass and their necromass can associate with mineral surfaces, contributing to long-term carbon persistence. This has generated interest in microbial interventions such as inoculation to restore carbon in degraded croplands, yet their efficacy remains uncertain. The uncertainty reflects a more fundamental, unresolved question: are microbially-mediated carbon transformations governed principally by the composition of the microbial community or by the soil microenvironment? To disentangle these drivers, we conducted a reciprocal microbial community transplant experiment, introducing communities of contrasting origin from locally adjacent grassland and cropland soils into sterilised grassland and cropland soils, and incubating them for eight months with regular organic inputs. This design decouples the inoculum from the microenvironment, allowing their individual and interactive contributions to be quantified. Fungal assembly was influenced more by the inoculum, consistent with dispersal limitation, whereas bacterial assembly was governed more by the microenvironment, consistent with environmental selection. Despite receiving the same organic carbon inputs, grassland and cropland recipient soils showed distinct SOC trajectories, indicating that the soil microenvironment strongly constrained net carbon retention. Within this constraint, community composition also mattered: introducing grassland rather than cropland communities increased fungal diversity and fungal necromass and led to better SOC outcomes, expressed as net gain or reduced loss. These results show that SOC accrual emerges from interactions between the soil microenvironment and microbial community composition, with fungal community assembly particularly associated with necromass accumulation and carbon retention. They highlight the need to consider both soil conditions and microbial community composition when developing strategies to enhance SOC accrual.

Microbial community assembly on leaves (the phyllosphere) is influenced by deterministic, stochastic, and historical processes. However, the importance of historical processes such as priority effects, where the timing and order of colonization influence community assembly, has not been extensively investigated in field-based phyllosphere studies. We designed a field experiment in a temperate forest in Quebec where we inoculated five strains of Methylobacterium onto the leaves of red maple and American beech trees, either early or late during the growing season. We quantified microbial community structure throughout the season using metabarcoding of a Methylobacterium-targeting rpoB primer as well as a 16S rRNA primer targeting the entire bacterial community. We show that the effects of inoculation on bacterial communities depend on inoculation timing: early-season inoculation led to strain-specific shifts in community composition, while late-season inoculation had no significant effect. Although the effect of early-season inoculation weakened over time, early- and late-season inoculation still led to different community compositions at the end of the growing season. Our study demonstrates that priority effects contribute to the assembly of phyllosphere bacterial communities under field conditions, with arrival timing and strain identity shaping community trajectories. Considering historical processes will thus be crucial for successful microbiome management.

Deadwood is a common ephemeral resource in boreal forests, but arthropod succession across the full decay gradient and transition into soil remains poorly understood. We analyzed the successional trajectory of arthropods in deadwood to soil. Further, we investigated whether the succession pattern differed in previously clear-cut and near-natural forests in southeastern Norway. This was done by DNA metabarcoding analyses of arthropod communities in collected deadwood and soil samples. We detected 741 arthropod OTUs, with 565 OTUs in deadwood and 291 in organic soil layers, of which 115 were found in both deadwood and organic soil layers. Arthropod richness increased with deadwood decay stage and organic soil layers supported higher richness than all deadwood decay stages. Community composition of arthropods changed significantly along the decay gradient, with late-decay stages sharing more OTUs with organic soil layers than with earlier decay stages. This suggests a gradual transition between communities in highly decayed deadwood and organic soil layers. Forest type (previously clear-cut vs. near-natural forest) had limited effects on overall richness and community composition, although previously clear-cut and near-natural forests supported partially distinct species pools and differed in co-occurrence patterns in late decay and organic soil layers. Our results show that arthropod communities are strongly structured along the decay gradient from freshly dead wood to organic soil layers. This highlights the importance of retaining deadwood across different decay stages for maintaining arthropod diversity and community convergence between deadwood and soil in boreal forests.

Abstract Background: Soil microbiomes play critical roles in plant health and resilience, yet it is still poorly understood how disruptions in local microbial communities, such as during soil management, impact these ecological functions. In this study, we investigated how compost addition, a widely used soil management practice, and microbiome origin influence microbiome-mediated plant resistance to insects. We combined surveys of working organic farms across New York with controlled laboratory experiments, amplicon sequencing, plant-insect bioassays, and mass spectrometry. Results: Compost use was associated with shifts in the relative abundance of 20 fungal and 2 bacterial genera across ten working farms. However, no consistent changes in bacterial or fungal diversity or community structure in fields with compost were observed across the farms. Under controlled conditions using a common compost source, compost increased rhizosphere microbial diversity and significantly altered rhizosphere community structure, including the relative abundance of 6 fungal and 41 bacterial genera. Despite these substantial community-level changes, compost did not affect populations of green peach aphids (Myzus persicae) on kale (Brassica oleracea). Instead, aphid populations and plant salicylic acid concentrations were more strongly associated with microbiome origin, demonstrating that compost can substantially restructure soil and rhizosphere microbial communities without corresponding changes in microbiome-mediated plant resistance to insects. Conclusions: Our findings demonstrate that microbial diversity and compositional responses to management are not necessarily reliable indicators of all microbiome functions. More broadly, this work highlights the importance of local soil microbiome variation in shaping plant-insect interactions and emphasizes the need to link community-level responses to direct functional measurements when evaluating microbiome responses to agricultural management.

Soil degradation is a widespread challenge that requires a broad response at the individual farm level. To ensure effectivity, the practices should be tailored to the farm context: land manager objectives and farm specific challenges. These have however been difficult to quantify. Here we demonstrate that a workable farm context can be created based on a value survey, open satellite and soil data, and published models for vegetation gross primary productivity and soil erosion. Based on the findings, despite individual differences, farmers value profitability and operational efficiency, but also biodiversity and soil health. At least the regenerative farmers surveyed also value working for the greater good more than maintaining tradition or power. In spite of wide differences in farm production orientation, we also found that each farm also had a broad variation in individual fields GPP. Most fields have a stable GPP level, which is either high or low, and that there is a 2-3-fold difference between the weakest and best producing fields indicating the potential for improving GPP by improving the growing conditions on currently weak fields. In addition, soil loss was found to be highly concentrated in critical source areas, where 10% of the field area contributed to 50% of the soil loss. Overall, open data can be linked to modelling workflows to rapidly produce a decision-making context for farmers. This facilitates benchmarking and co-learning as well as enables land managers and advisors to identify the farm context for planning effective responses to soil degradation.

Pyrroloquinoline quinone (PQQ) is known to promote plant growth, yet how the rhizosphere microbiome varies with PQQ concentration remains poorly understood. We applied metagenomic sequencing to characterize the taxonomic composition and functional potential of the tobacco rhizosphere microbiome across PQQ treatments at 0.5, 1 and 2 mol/L plus an untreated control. The rhizosphere microbiome was dominated by Pseudomonadota and Actinomycetota and differed among treatments in a concentration-associated, non-monotonic manner. The most pronounced differences were observed at 1 mol/L, where alpha diversity showed dimension-specific variation and beta-diversity analysis resolved the most distinct community profile. Taxonomic and functional profiles varied concurrently, with Streptomyces, Sphingomonas, Rhodanobacter and Lysobacter, together with functions related to biosynthesis, energy metabolism, colonization and environmental sensing, showing higher relative abundance at this concentration. No broad-spectrum antimicrobial effect was detected at the community level, and antibiotic resistance gene abundance showed no significant differences among treatments after correction for multiple testing. These findings provide a basis for further evaluation of PQQ in modulating the rhizosphere microbiome in continuous cropping systems.

1. Grassland ecosystems are pivotal for global biodiversity, carbon (C) storage and food security. This biome, however, together with the ecosystem services it provides, is threatened by global change perturbations. These perturbations rarely occur in isolation and most often affect environments simultaneously, which is a pressing issue in ecology. Nevertheless, most of the research conducted so far has focussed on single simultaneous perturbations or pairs thereof. The few examples considering the effect of more than two simultaneous perturbations focussed only on plants or soil separately, which ignores the potential buffering or feedback effects on ecosystem functioning induced by plant-soils interactions. 2. To tackle this knowledge gap, we used an experimental setup involving mesocosms (soil and plants intact) collected in an extensively managed permanent grassland. Mesocosms were arranged in a greenhouse experiment where we applied individual and combined global change perturbations (up to ten in total) including application of fertilisers, pesticides and antibiotics, simulated trampling and grazing, heat stress and drought. Measured ecosystem functions and properties included a large set of biological, physical and chemical soil and plant associated variables. 3. Results showed that multiple perturbations in most cases had negative effects irrespective of the direction found for individual perturbations. However, in contrast to previous bare soil experiments, we only found scarce evidence for substantial synergistic effects of simultaneous perturbations in our experiment conducted with mesocosms that contained vegetation. This suggests a mitigating impact of plants on soil responses to global change. Moreover, we found a strong dominative effect of drought on ecosystem functioning, driving most of the effects observed. 4. Synthesis: Our results highlight the importance of evaluating global change impacts under more realistic settings, i.e., applying multiple perturbations simultaneously and including plant-soil interactions. Mitigation of global change in terrestrial ecosystems will only be possible once we holistically understand how ecosystems respond to altered conditions.

Sinorhizobium meliloti is a nitrogen-fixing soil bacterium that forms a facultative mutualism with its host alfalfa. S. meliloti strains exhibit diverse colony morphologies on solid culture media that span a continuum from dry to mucoid. Studies on how this trait affects symbiosis rely on mutations in exopolysaccharide II production genes; however, whether natural variation in morphology confers a selective advantage on rhizobia in their natural habitats remains unknown. Here, we used 90 mucoid and 27 dry natural isolates to test whether colony morphology is associated with rhizobial fitness in the soil and in the host, or with the nitrogen-fixation benefits they provide to the plant. Colony morphologies were widely distributed across a phylogenetic tree, suggesting that morphological shifts occurred repeatedly and no single genetic variant was strongly associated with this trait. We inoculated soil mesocosms and plants with a mixture of dry and mucoid bacteria. We observed that dry rhizobia have higher fitness, particularly at 22{degrees}C and 32{degrees}C, but not under cold or drought conditions, independent of the initial rhizobial load. Conversely, mucoid bacteria have a modestly higher relative fitness in host nodules, and single inoculations showed that they tend to confer greater benefits to all three alfalfa varieties. Over time, we also observed rare, repeated conversion from mucoid to dry morphologies in soil and host plants. Taken together, our study reveals that morphological variation within a species in a single agricultural field is important for bacterial fitness in the soil and can have cascading effects on the rhizobia's plant benefits.

An increasing number of researchers, educators, and at-home growers are turning to hydroponics as an alternative method of food production, diversifying and strengthening the food supply chain. This has led to a substantial increase in the amount of academic work involving hydroponic production of plants for a variety of purposes, including but not limited to a more controlled and customizable environment than conventional production methods, utilizing hydroponics as a method of wastewater treatment, and investigating the vertical production of plants on a much smaller footprint than traditional commercial-scale production. Because so many unique stakeholders are interested in hydroponics for a variety of reasons, academic studies use a wide variety of hydroponic systems with varying levels of technology and automation, making comparisons across studies and systems challenging. A few institutions have sophisticated plant growth and research facilities, like those used by commercial companies, but these systems are often prohibitively expensive, costing upwards of $10,000 USD for a very limited amount of growing space for experimental trials. To enable more researchers, educators, and citizen scientists to conduct experiments and easily compare their results, this study details three pilot-scale hydroponic production systems (Kratky, NFT, and DWC), utilizing entirely off-the-shelf components, for under $5,000 USD each, that are capable of maintaining the desired consistent temperature and relative humidity levels, and have space for 216, 108 (6 irrigation loops), and 64 (16 irrigation bins) plants, respectively. The material lists and prices are provided along with assembly instructions and general guidelines for each hydroponic system. The testing and optimization process of environmental conditions within each growth system is also detailed, with suggested customizations for potential experimental setups. The authors developed these systems during their Masters and Doctoral degree programs, enabling improved hydroponic research at the University of Illinois Urbana-Champaign. They hope that other aspiring hydroponic researchers can benefit from this work in the development and operation of their hydroponic systems, increasing research efficiency and collaboration opportunities in this field of study.

The potential of alternative agricultural systems, such as organic or conservation agriculture, for biodiversity restoration has been widely investigated. However, variability of practices within each of these two categories of agricultural system has rarely been accounted for. Furthermore, these systems have most often been studied separately, isolating either organic or conservation agriculture (itself often reduced to a soil tillage reduction), and rarely analyzing these systems side by side. This study attempts to disentangle these multiple interrelationships by sampling carabid beetles in a network of 48 commercial Belgian farms including organic agriculture (OA), conservation agriculture (CA), farms combining the two approaches (OCA) and farms applying conventional practices (CVA). In each farm, we sampled carabids using pitfall and emergence traps in one winter cereal field and collected a detailed description of crop management practices. We found that community composition was primarily structured by seasonality early in the season (March, April) followed by convergence (May, June) driven by the aggregation of the most dominant species. Based on agroecosystem classification, organic certification (i.e., the absence of synthetic pesticide use) exerted a twofold stronger effect than application of conservation agriculture principles (i.e., reduced or no soil tillage) on carabid beetle community composition. Notably, OCA supported carabid assemblages that were structurally distinct from those of CA and CVA. Furthermore, carabid communities associated with OA differed significantly in composition from those of CVA. Observed and estimated species richness were also significantly higher in OCA than in CA and CVA, while OA differed from CVA only for observed richness. Beyond differences among agricultural systems, community responses were associated with specific management practices, which explained nearly a quarter of the compositional variation with significant influence of the duration since organic conversion and the frequency of synthetic pesticide application. Carabid abundances were negatively affected by synthetic pesticides and moldboard ploughing, whereas richness was more strongly related to the time since conversion to OA, cover crops, and organic amendments. Overall, these results position synthetic inputs and time since conversion as the main filters over carabid communities. Our study highlights the importance of jointly considering system level analyses and detailed management practices to better understand the complex relationships between agricultural practices and carabid communities.