Mouldboard ploughing has been associated with a loss in soil quality, while reduced tillage is often reported to result in crop yield declines. Occasional ploughing every few years could be an attractive compromise, but it remains unclear whether such a system results in a combined benefit of improved crop yield and soil quality. Here, we present data from a 43-year old field experiment on a clay soil in central Sweden. We analysed how three different tillage systems – annual mouldboard ploughing, continuous shallow tillage, and shallow tillage with occasional mouldboard ploughing – affect crop yields and soil properties with the objective of assessing joint response patterns between crop production and soil quality indicators reflecting soil structure, soil organic carbon storage, and habitat for soil biota. Crop yields were not affected by the tillage systems. Characteristics of the soil pore system and soil biota were similar in the occasional ploughing and annually mouldboard ploughed systems. Shallow tillage significantly altered microbial community composition relative to ploughed treatments, increasing bacterial and fungal abundances and reducing diversity in the upper topsoil layer, likely due to stratified soil carbon stocks. There was also a higher proportion of biopores in shallow tillage, which could be advantageous during dry spells that are expected to become more frequent and severe with climate change. Nevertheless, there were only small effects on water retention, biomass of nematodes and earthworms, and most of the abiotic soil properties. We conclude that occasional ploughing did not offer advantages at our site, and our results show that no system improved yield and all soil quality indicators simultaneously.

Historical land-use changes shape present-day biodiversity through legacy effects, but the duration and mechanisms of these legacies are poorly understood. We used historical land-use maps in two Swedish landscapes across three centuries to examine the persistent influence of historical land use on plant and soil microbial communities. Overall, bacteria showed stronger legacy effects than fungi, but effects varied across functional groups of plant-associated and free-living taxa. However, soil-borne plant pathogenic fungi showed a persisting influence of arable land use which gradually disappeared after ~150 years, suggesting that land-use legacies decay over time. This dilution could relate to changing plant communities but also to changes in microbial associations, as suggested by species co-occurrence patterns over time. Our findings provide novel and crucial information on the duration of land-use legacies and single out soil-borne plant pathogens as key indicator groups of historical land use in present-day ecosystems.

Flower plantings in agricultural landscapes can contribute to sustainable crop production by enhancing pollination and biological control services. However, selecting plant species that promote multiple ecosystem services is challenging, since plants that favor pollinators may not equally foster natural enemies, and potential trade-offs, such as inadvertently promoting crop pests, must be considered. This complexity increases when accounting for belowground effects. We evaluated 27 candidate plant species for their ability to host functionally important above- and belowground organisms—pollinators, natural enemies, herbivores, and decomposers—and assessed how plant characteristics such as floral area, timing of peak bloom, life cycle, and plant cover affect these organism groups. We found that certain plant species have the potential to support several groups of beneficial organisms, suggesting they can enhance multiple ecosystem services. Annual plants had higher abundances of both above- and belowground beneficial organisms compared to perennials. Greater plant cover was positively associated with hoverfly abundance. Several functionally important organism groups were positively correlated across plant species, but these positive correlations were not explained by shared responses to plant characteristics. Our findings underscore the significance of plant species identity and characteristics in designing flower plantings for enhancing biodiversity and ecosystem services and highlight the importance of including belowground organisms like nematodes in future studies. Our results for specific plant species and plant characteristics can be used to design flower mixtures supporting several ecosystem service providers while considering potential trade-offs, thereby increasing the efficiency of flower plantings.

Flower strips are an agri-environmental measure to contribute to sustainable crop production by enhancing pollinators and natural enemies of pests. However, most strips are designed to target a single ecosystem service, often overlooking simultaneous effects on multiple functional groups of arthropods. In Sweden, large-scale adoption of flower strips to promote pollinators through the 'Sweden Blossom' initiative represents an opportunity to deliver benefits beyond single goals, and to support multiple ecosystem services. We assessed how an annual flower strip mixture influences the pollinators targeted as well as the abundance of natural enemies and herbivores, their spillover 10 m into neighbouring crops and pest control. Pollinators were recorded via visual observations in the strips. Leaf-dwelling arthropods were recorded with yellow sticky traps, and ground-dwelling predators with pitfall traps in both the strips and adjacent spring barley fields. Natural enemies and herbivores in the crop were also assessed through tiller counts, while aphid predation rates were estimated using sentinel prey cards for leaf- and ground-dwelling predators. The flower strips strongly increased pollinator abundances as intended but also increased the abundance of certain natural enemy and herbivore taxa, some of which also dispersed into neighbouring crops. However, arthropods present on crop tillers or pest control rates by leaf-dwelling predators were not affected. Aphid predation by ground-dwelling predators tended to increase in crop areas near the flower strips. These findings have implications for designing agri-environmental measures, stressing the importance of context-specific factors to maximise ecosystem service delivery and minimise potential unintended consequences.

Agricultural management is critical in shaping soil carbon (C) stocks, pools and fluxes. The soil priming effect (PE) is known as a key component of the global C cycle that reflects alterations in soil organic carbon (SOC) mineralization induced by fresh C inputs. Here, we show that priming can help to predict soil C content across European Long-Term Experiments (LTEs), a result which was maintained at continental and global scales. Results reveal that lower-intensity management significantly enhances PE in soils from European croplands. Conversely, high-intensity management led to lower or even negative PE. Management intensity influences PE directly through alterations in SOC and indirectly by modifying aggregates stability and microbial biomass. Both fertilization and tillage affect PE, with soils under organic fertilization and no-tillage showing higher values of PE. These findings advance our understanding of the long-term impacts of agricultural management on the C cycle at the continental scale.

Effects of tillage in arable fields on taxonomic and functional responses of beneficial above- and below-ground arthropod communities are poorly understood. We assessed arthropod communities in 30 conventionally managed crop fields in south-western Sweden before and after autumn tillage. Treatments consisted of three levels of tillage intensity: inversion tillage, reduced tillage (non-inversion) and no tillage (direct seeding). Reduced tillage and no tillage are considered conservation tillage practices. All fields were sown with winter cereals in autumn 2019, followed by winter oilseed rape sown in late summer 2020. Tillage occurred between cereal harvest and the sowing of winter oilseed rape. We measured soil mesofauna density, and density, taxonomic, compositional and functional diversity of ground-dwelling predators. Inversion tillage decreased densities of above- and below-ground beneficial arthropods. Conservation tillage resulted in higher species richness and lower community turnover following disturbance. Community compositional shifts following inversion tillage were characterised by lower community weighted mean (CWM) body size and reduced densities of carabids overwintering as imago in autumn, and higher spider CWM body size in spring, compared with conservation tillage treatments. Inversion tillage reduced spider density and richness throughout the following growing season, while soil mesofauna densities, carabid taxonomic diversity and functional composition recovered by spring. Synthesis and applications: Responses to tillage were taxon-specific and likely depended on life-stage and the dependency on structural habitat complexity. Management should balance trade-offs between retaining local communities, meeting the needs of multiple taxa, and accounting for taxonomic and functional richness over time.

Flower strips are a valuable agri-environmental measure to foster ecological intensification by providing floral and nesting resources to beneficial organisms. Nevertheless, few flower strip studies integrate assessments of multiple ecosystem services and their providers (simultaneous promotion of pollinators and natural enemies) or consider trade-offs (unintended promotion of pests in adjacent crops). This gap is further exacerbated if below-ground functions are considered. We sampled pollinators, natural enemies, and herbivores using visual observations, yellow sticky traps, pitfall traps, and tiller counts in ten pairs of perennial flower strips and control field margins, and their adjacent cereal fields in Scania, Sweden, in 2021. In addition, we estimated predation and below-ground decomposition rates with sentinel prey cards and bait lamina strips. Flower strips increased floral availability, pollinator, natural enemy and herbivore abundances, relative to control field margins. Natural enemy and herbivore responses to the implemented strips were taxon-specific. The positive effects of flower strips extended beyond the strips themselves, as spillover effects were evident for several natural enemy groups, with increased abundances in adjacent crop fields. A trade-off was also observed: pest thrips were more abundant in crop tillers near flower strips than near controls. No effect of flower strips on aphid predation rates was observed. Decomposition rates were as high in flower strips as in controls, despite flower strips only being established for two years. These findings emphasize flower strips’ potential to support multiple ecosystem service providers, while underscoring the importance of context-specific design and management to maximize benefits and avoid unintended trade-offs.

Land abandonment is the single largest process of land-use change in the Global North driving succession and afforestation at continental scales, but assessing its impacts on soil microbial communities remains a challenge. Here, we establish a nationwide successional gradient of paired grassland and forest sites to track developments in microbial structure and functioning following land abandonment and gradual land-use change to forests. We show that microbes generally respond through threshold dynamics, leading to increasing functional but decreasing taxonomic diversity. Succession also entailed specialization of microbial nutrient (C-N-P) cycling genetic repertoires while decreasing genetic redundancy. This highlights a putative trade-off between two desirable ecosystem properties: functional diversity and functional redundancy. Fungal functional diversity underpins higher microbial C-cycling capacity, underscoring the link between functional traits and ecosystem processes. Changing litter quality similarly provides a mechanistic link between plant and microbial communities despite otherwise largely decoupled successional developments above- and belowground. While land abandonment is frequently touted as an opportunity to increase biodiversity and carbon storage, our results show that deeper knowledge about the multifaceted development of soil microbial communities and their links to plant communities during succession may be needed to fully grasp the impacts of global land abandonment processes.

Intensive management of arable land reduces earthworm density and diversity. This may impair earthworm-mediated soil functions, such as nutrient mineralization and soil structure formation. To sustain earthworm source populations for re-colonization of cultivated soils, it is therefore important to preserve habitats with high earthworm diversity. Semi-natural grasslands, with a long continuity without soil disturbance, could serve as such earthworm diversity reservoirs. This is particularly important in mixed agricultural landscapes with elements of multiple land uses. Nonetheless, earthworm density and diversity vary greatly among grasslands. To preserve and optimally manage the most suitable grasslands, knowledge about which grassland characteristics best explain earthworm diversity is needed. Additionally, we have a limited picture of earthworm diversity in general, because previous studies have neglected juvenile earthworms and cryptic species. The juvenile fraction commonly comprises the main part of earthworm samples, whereas morphologically inseparable cryptic species account for an unknown fraction. This fraction is of particular importance, as juveniles reflect the local reproductive and regeneration potential of earthworm populations and communities. To determine the full species composition of earthworm communities, we sampled earthworms from 28 semi-natural grasslands in south-central Sweden and identified them to species by DNA barcoding. To test how grassland characteristics explain earthworm density, diversity, and community composition, we measured several characteristics of soils, vegetation, and management of the grasslands, and descriptors of the surrounding landscape. DNA barcoding revealed nearly twice as many species as were identified morphologically. Earthworm densities were higher in grasslands with higher Ellenberg moisture indicator values and lower soil C:N ratios. The diversity and occurrence of many earthworm species was also higher in grasslands with higher soil moisture indicator values and lower C:N ratios, and further increased with habitat heterogeneity. Certain species occurred more likely in grasslands with higher grazing intensity. Epigeic earthworms, which live in and feed on surface litter, were more common in grasslands with higher moisture indicator values and SOM content. Thus, dry and relatively unproductive semi-natural grasslands, which are common in Sweden, are unlikely to sustain high earthworm diversity – a pattern contrasting to previously reported plant diversity responses. Instead, earthworm diversity seems concentrated to more productive grazed grasslands, with large within-grassland heterogeneity. Therefore, we highlight the importance of considering soil animals in conservation policies for semi-natural grasslands.

CONTEXT: Agriculture plays a central role as a feedstock provider for the bioeconomy. However, utilization competing with food production and associated land use change have previously been a matter of debate. Nonetheless, strengthening the productivity of agroecosystems through sustainable intensification can prevent the depletion of natural resources, enhance food security, and facilitate adaptation to and mitigation of climate change. OBJECTIVE: This study explores the effects of combining crop residue removal for use as biomass feedstock with the establishment of intermediate crops to compensate for organic carbon depletion in arable land in Sweden. METHODS: The analysis relied on Swedish national agricultural statistics at the highest available spatial resolution (yield survey district). Crop residue calculations factored in crop:residue ratios, and harvestable and recoverable potentials. A model was devised to estimate land availability for cultivating intermediate crops based on generalized crop rotation sequences, and a spatial interpolation was employed to determine oilseed radish yields as a model intermediate crop. Estimates of long-term soil carbon inputs hinged on biomass carbon content and humification coefficients dependent on soil clay content. RESULTS AND CONCLUSION: The total annual residual biomass availability in the country stands at approximately 2139 kt per year. The potential harvestable biomass production from intermediate crops was estimated at 383 kt per year. However, spatial differences were evident in total biomass production and effects on soil organic carbon inputs. For the majority of districts, the inclusion of intermediate crops could offset the negative effect of a complete removal of crop residues on soil organic carbon inputs. In other cases, establishing intermediate crops could not compensate for these negative effects, but some differences were observed when comparing the harvesting and the incorporation of the intermediate crops' biomass. Spatial disparities originated from variations in soil texture, intermediate crop yield, and rotation sequences. SIGNIFICANCE: This research is an attempt to address the challenge of maintaining and increasing the soil carbon stocks under the context of a growing biomass demand in a developing biobased economy. It highlights the divergent effects of combining crop residue removal with the inclusion of intermediate crops under distinct agroecological conditions in the Northern European context. By giving estimates on biomass availability and effects on soil organic carbon inputs, we provide information that can support decision making for bioeconomy planning and sustainable resource utilization. This also has long-term implications for preservation of soil fertility, agricultural productivity and climate change mitigation.

Heavy metal pollution has important effects on ecosystem nitrogen (N) cycling, but factors driving differences between the direction, onset and intensity of responses are poorly understood. We used two contrasting grassland soils to examine the effects of copper (Cu) on the abundance and activity of N cycling microbial guilds and plant responses, including plant delta 15N as an integrator of the N cycle. A low pH sandy soil and a high pH sandy loam soil were aged two years in outdoor mesocosms with copper (Cu) treatments of background, 200, 400 or 1000 mg kg-1 Cu. After two years, increased Cu treatments resulted in significantly lower abundances of ammonia oxidizing archaea, Nitrospira nitrite oxidizing bacteria (NOB), potential ammonia oxidation rates and plant biomass in both soils. Plants possessed significantly increased N content and enriched shoot delta 15N in with higher Cu in both soils. While abundances of ammonia oxidizing bacteria were unaffected by Cu, the response among Nitrobacter NOB and denitrifiers and plant delta 13C differed between the two soils. In contrast to plants, differences in the intensity and direction of microbial guild responses were not explained by increasing soluble Cu but rather shaped by soil type. This indicates that the two soils differed in metal bioavailability to plants, as well as harbored microbial communities with inherent differences in metal sensitivity. Furthermore, effects of increasing Cu on microbial N-cycling guilds became more apparent with longer incubation time, emphasizing the importance of long-term studies to assess important ecosystem effects of Cu contamination. Taken together, we conclude that a combination of plant and microbial responses can give better insights on how Cu is affecting the N cycle in polluted soils.

Biological control has developed into a realistic alternative to replace chemical pesticides. A long-awaited paradigm shift is now adopted by the European Commission through a proposed new Regulation on sustainable use of plant protection products. Unfortunately, the scientific framework underpinning biocontrol is seriously neglected, impeding transition to sustainable plant production.

Background and aims Supporting arbuscular mycorrhizal (AM) nutrient acquisition in crops may reduce the need for fertilizer inputs, leading to more cost effective and sustainable crop production. In wheat, AM fungal responsiveness and benefits of symbiosis vary among varieties. This study explored the role of soil compaction in this variation. Methods We examined in a field experiment how soil compaction affects AM fungal colonization and biomass in five spring wheat varieties, and how these varieties differ in their AM-mediated phosphorus (P) uptake. We also studied soil properties, and AM fungal community composition in roots and soil. Results Soil compaction increased AM fungal colonization in the variety Alderon, characterized by root traits that indicate inefficient P uptake. Wheat P concentration and P:N ratio in Alderon and Diskett increased with increased root AM fungal colonization and biomass. In Diskett, which is the most cultivated spring wheat variety in Sweden and has intermediate root traits, total P content per m 2 also increased with root AM fungal colonization and biomass. Conclusions Some wheat varieties, potentially those characterized by P inefficient root traits, such as Alderon, may depend more on AM-mediated P uptake in compacted than in non-compacted soil. Increased P uptake with increased AM fungal colonization in Diskett suggests that efficient root and AM-mediated nutrient uptake can occur simultaneously in a modern variety. Breeding varieties that use roots and AM symbiosis as complementary strategies for nutrient uptake could improve nutrient uptake efficiency and help farmers achieve stable yields in varying conditions.

Understanding the processes that underpin the community assembly of bacteria is a key challenge in microbial ecology. We studied soil bacterial communities across a large-scale successional gradient of managed and abandoned grasslands paired with mature forest sites to disentangle drivers of community turnover and assembly. Diversity partitioning and phylogenetic null-modelling showed that bacterial communities in grasslands remain compositionally stable following abandonment and secondary succession but they differ markedly from fully afforested sites. Zeta diversity analyses revealed the persistence of core microbial taxa that both reflected and differed from whole-scale community turnover patterns. Differences in soil pH and C:N were the main drivers of community turnover between paired grassland and forest sites and the variability of pH within successional stages was a key factor related to the relative dominance of deterministic assembly processes. Our results indicate that grassland microbiomes could be compositionally resilient to abandonment and secondary succession and that the major changes in microbial communities between grasslands and forests occur fairly late in the succession when trees have established as the dominant vegetation. We also show that core taxa may show contrasting responses to management and abandonment in grasslands.

Sustainable food production requires agriculture to conserve biodiversity and facilitate ecosystem services to maintain productivity levels while reducing inputs detrimental to ecosystem functioning. Increasing within-field vegetation diversity by legume intercropping seems promising to facilitate cropping system multi-functionality. Effects of intercropping with legumes on biodiversity-mediated ecosystem services such as pollination or natural pest control are, however, not sufficiently understood. Using 26 observation plots in a paired field design, we studied the effects of undersowing oats with a mixture of three annual clovers across different aspects of cropping system multi-functionality. We investigated 16 below- and above-ground ecosystem service indicators related to soil mineral nitrogen, arable weed control, pollination, disease and pest pressures, natural pest control and crop yield. We found lower arable weed cover, higher flower cover and pollinator densities as well as decreased root-feeding nematode densities in intercropped observation plots compared with the non-intercropped controls. However, intercropping decreased spider activity densities and oat yield nitrogen content. Root diseases, pest damages, natural pest control and crop yield were not affected by intercropping. The biomass of undersown clovers was positively related with the differences in flower cover and pollinator densities, and negatively related with the differences in arable weed cover between the intercropped and the control treatment. Synthesis and applications: We demonstrate that undersowing annual clovers suppresses arable weeds and simultaneously support pollinators without reducing crop yields or taking land out of arable production. Undersown plant mixtures should, however, be tailored to support a wider spectrum of pollinators and benefit natural pest control to support a higher level of overall cropping system multi-functionality.