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Fungi play a pivotal role as highly effective decomposers of plant residues and essential mycorrhizal symbionts, augmenting water and nutrient uptake in plants and contributing to diverse functions within agroecosystems. This study examined soil fungi in 188 wheat fields across nine European pedoclimatic zones under both conventional and organic farming systems, utilizing ITS1 amplicon sequencing. The investigation aimed to quantify changes induced by the farming system in soil fungi and their correlation with soil features and climatic factors across these pedoclimatic zones, spanning from northern to southern Europe. The pedoclimatic zone emerged as a key determinant in shaping the overall composition of the fungal community. Zones characterized by moist and cool climates, along with low levels of available phosphorus and carbonate, exhibited higher fungal richness. However, variations in fungal diversity and relative abundances were observed within zones due to farming system-induced changes. Soil pH and bulk density were identified as major factors, for example, they correlate with an increase in potential pathogenic taxa (Mycosphaerella , Nectriaceae, Alternaria) in two Mediterranean zones and with an increase of potential plant growth promoting taxa (Saitozyma , Solicoccozyma) in the Boreal zone. Organic farming, in general, promoted elevated fungal richness. The Lusitanian and Nemoral zones under organic farming exhibited the highest fungal richness and diversity. In terms of organic farming, both symbiotrophs and potential pathogens increased in the Lusitanian zone, while pathotrophs were more prevalent in the Central Atlantic and South Mediterranean zones under organic farming. These findings propose potential indicators for organic farming, including fungal endophytes in zones characterized by a moist and cool climate, low available phosphorus content, and low soil pH. Organic farming may favor mycorrhizae and potential pathogens in zones with drier and warmer climates, along with higher soil pH, calcium carbonate content, and bulk density. This study provides novel insights and underscores the significance of regional climatic and edaphic conditions in shaping the soil fungal community in different farming systems within European wheat fields. • Regional climatic and soil conditions shaped the soil fungal community of fields. • Effects of farming system on fungal community depended on the pedoclimatic zone. • Organic farming potentially increased symbiotrophic and pathogenic fungi. • Soil pH, bulk density and phosphorus level affected the abundance of fungi. • Different functional fungal groups characterized southern and northern Europe. [ABSTRACT FROM AUTHOR]

Genotypic tradeoffs along environmental gradients help maintain diversity in functional traits in the wild and limit the range of suitable environments for each genotype in tree breeding programmes. Little is still known of the capacity of abiotic and biotic soil variation to generate marked shifts in genotypic performance ranks. We examined the potential of belowground soil factors to bring about genotype × environment interactions in a tree species by combining data from extant field trials and a new seedling-based progeny experiment. We first analysed genotypic growth patterns of Norway spruce (Picea abies) at two field trial locations, a native forest site and a former agricultural field, that exhibited biotic and abiotic soil variation. While we found significant genotype × location interactions in growth, we also observed positive between-location genotypic correlations, indicating similar genotypic rank orders across divergent soil types. Contributing to the genotype × environment interactions, differences in age at the time of growth measurements may explain why genetic variances nevertheless differed between the locations. The subsequent progeny experiment with soil and seeds collected at the trial locations enabled controlled treatments in a growth chamber that tested the capacity of between-location soil variation to induce genotype × environment interactions in seedling traits. The progeny experiment revealed that the soil treatment had major effects on averages in all 14 shoot and root functional traits, with four groups of correlated traits (e.g., estimates of shoot and root system size) identified by a principal component analysis. Seed collection location affected only few traits, and the more southern agricultural field trial yielded slightly larger seedlings with delayed phenology. Yet, despite significant genetic variation, no seedling trait manifested genotype × soil treatment interactions, which may be due to the soil treatments not mirroring spatial heterogeneity of the soils at the trial locations, or to our limited subsample of ten genotypes in the progeny experiment. Taken together, our results on adult trees and seedlings indicate that overall tree growth is impacted by variation in belowground environmental factors, but further research with more comprehensive sampling is needed to determine whether they have potential to generate location-specific patterns of genotypic performance in economically valuable tree species. • Biotic and abiotic soil variation may cause genotypic tradeoffs in Norway spruce. • We combined observations from two field trials and a new progeny experiment. • We found tradeoffs in growth in adult trees, but not in seedling functional traits. • Genetic and soil variation had independent effects on functional trait variation. [ABSTRACT FROM AUTHOR]

Only recently there has been a strong focus on the impacts of microplastics on terrestrial crop plants. This study aims to examine and compare the effects of microplastics on two monocotyledonous (barley, Hordeum vulgare and wheat, Triticum aestivum), and two dicotyledonous (carrot, Daucus carota and lettuce, Lactuca sativa) plant species through two complimentary experiments. First, we investigated the effects of low, medium, and high (103, 105, 107 particles per mL) concentrations of 500 nm polystyrene microplastics (PS-MPs) on seed germination and early development. We found species-dependent effects on the early development, with microplastics only significantly affecting lettuce and carrot. When acutely exposed during germination, PS-MPs significantly delayed the germination of lettuce by 24%, as well as promoted the shoot growth of carrot by 71% and decreased its biomass by 26%. No effect was recorded on monocot species. Secondly, we performed a chronic (21 d) hydroponic experiment on lettuce and wheat. We observed that PS-MPs significantly reduced the shoot growth of lettuce by up to 35% and increased its biomass by up to 64%, while no record was reported on wheat. In addition, stress level indicators and defence mechanisms were significantly up-regulated in both lettuce and wheat seedlings. Overall, this study shows that PS-MPs affect plant development: impacts were recorded on both germination and growth for dicots, and responses identified by biochemical markers of stress were increased in both lettuce and wheat. This highlights species-dependent effects as the four crops were grown under identical conditions to allow direct comparison. For future research, our study emphasizes the need to focus on crop specific effects, while also working towards knowledge of plastic-induced impacts at environmentally relevant conditions. [Display omitted] • Microplastics significantly impacted germination and growth in lettuce and carrot. • No effects of microplastics were recorded on wheat and barley growth. • Biochemical stress indicators were up-regulated in both lettuce and wheat. • Our results highlight species-dependent effects of microplastics on crops. [ABSTRACT FROM AUTHOR]

Intensified arable farming results in fewer functional groups of soil biota with decreased biodiversity. Organic farming with slurry fertilization and long crop rotation cycles favors soil fauna diversity under tropical and temperate conditions. Faunal responses to agricultural practices in northern latitudes may, however, differ from those in southern latitudes due to different soil types, climatic conditions, and intensity of management. We investigated the abundance and diversity of soil fauna communities (nematodes, microarthropods, enchytraeids and earthworms) in a boreal sandy soil in replicated organically and conventionally cultivated field blocks that simulated cultivation in a cereal farm and in a forage producing dairy farm. In addition to traditional methods, we investigated nematode diversity using DNA metabarcoding. The results show that organic production system did not unequivocally result in higher abundance and diversity of soil fauna compared with conventional production systems, neither in the cereal nor the dairy farming type. Instead, abundances of all soil fauna groups were typically higher in the dairy than in the cereal farming type irrespective of production system. This holds up for all functional groups of nematodes except omnivores, all four orders of Acari present, two out of the six families of Collembola, the total number of enchytraeids and density of earthworms. Nematode diversity, measured as average ZOTU number, was in conventionally cultivated cereal farming type an order of magnitude lower than in other production and farming type combinations. Of the various differences between farming types, the crop species was the most important one as it defines the management practice and thus the soil conditions where soil biota lives. Our findings underline that when comparing soil faunal communities under organic and conventional cultivation, the differences between farming types need to be considered in addition to the production system as they can have an overriding importance across the food web. [Display omitted] • Organic production does not unequivocally result in higher soil fauna diversity. • Organic fertilizers and diverse crop rotation favor soil fauna community development. • Abundancies of soil fauna groups were higher in dairy than cereal farming types. • When assessing the impacts of organic production, farming type should be considered. [ABSTRACT FROM AUTHOR]