Agriculture, Ecosystems & Environment

AimsHarnessing rhizosphere processes offers a valuable opportunity to optimize nutrient use efficiency in agroecosystems. In nutrient-limited soils, plants discharge part of photosynthate surplus via root exudation, including carboxylates, which may enhance mineral dissolution and nutrient mobilization. We aimed to assess how plant responses to nutrient limitation translated into changes in exudate profiles, and how these exudates, in turn, drive bioweathering across soils of contrasting mineralogy and weathering degree. MethodsWe conducted a hydroponic experiment with Lupinus albus grown in a phosphorus (P) gradient over seven weeks. We measured plant biomass and root traits, performed a metabolomics analysis and quantified seven carboxylates in root exudates using gas chromatography-mass spectrometry. To assess bioweathering across contrasted soil domains, we conducted batch dissolution tests with exudates using three soil horizons--each with distinct physicochemical properties: enriched in organic matter, iron oxides, or primary silicates. ResultsAt the intermediate level of P supply, shoot biomass was comparable to that under high P, but plants produced more root biomass and a higher total carboxylate exudation rate. Despite low carboxylate concentrations (<100 ppb), exudates promoted the dissolution of Ca, Mg, Si, Fe, P and K in all soils. Yet, the degree of element released varied among soil types. ConclusionThese findings highlight the importance of root exudates in enhancing mineral dissolution, with effects dependent on soil physicochemical properties. The results suggest that managing agroecosystems under moderate nutrient limitation could be a sustainable strategy to increase root-to-shoot ratios, enhance bioweathering and nutrient release in rhizosphere.

O_LIOrganic farming is seen as a prototype of ecological intensification able to conciliate crop productivity and biodiversity conservation in agricultural landscapes. However, how natural enemies, an important functional group supporting pest control services, respond to organic farming at different scales and in different landscape contexts remain unclear.\nC_LIO_LIUsing a hierarchical design within a vineyard-dominated region located in southwestern France, we examine the independent effects of organic farming and semi-natural habitats at the local and landscape scales on natural enemies.\nC_LIO_LIWe show that the proportion of organic farming is a stronger driver of species abundance than the proportion of semi-natural habitats and is an important facet of landscape heterogeneity shaping natural enemy assemblages. Although our study highlight a strong taxonomic group-dependency about the effect of organic farming, organic farming benefits to dominant species while rare species occur at the same frequency in the two farming systems.\nC_LIO_LIIndependently of farming systems, enhancing field age, reducing crop productivity, soil tillage intensity and pesticide use are key management options to increase natural enemy biodiversity.\nC_LIO_LISynthesis and Applications. Our study indicates that policies promoting the expansion of organic farming will benefit more to ecological intensification strategies seeking to enhance ecosystem services than to biodiversity conservation.\nC_LI

Weed management is a resource-intensive practice in arable agriculture, with direct and long-term impacts on both productivity and biodiversity (e.g. plant, pollinators and farmland wildlife). In conventional systems, weed control relies on crop management and herbicide inputs, but for more sustainable production systems, use of herbicides needs to be reduced. This requires a good understanding of the processes that regulate arable weed dynamics in arable fields. We adopted a systems framework to understand and model interacting components that drive the weed dynamics in 168 arable fields. Within this framework, we built a structural equation model (SEM) to quantify the direct and indirect effects of crop rotation (i.e. crops in the previous three years and the current year) and carabid beetles (Coleoptera: Carabidae) on weed density, seed abundance and accumulation in the seedbank. We included results from a mechanistic approach to infer interactions between seed-feeding carabid beetles and seeds to estimate predation pressure in each field. Our results show that weeds in arable fields are regulated by crop type, sowing season, and activity density of carabid beetles. We found a direct effect of crop rotation, including both past and current field management practice, on weed abundance in the field and its seedbank. There was also an indirect effect of crops on weed seed accumulation in the seedbank via the effect of seed-eating carabid beetles. The efficiency of weed control by carabid beetles depended on the cumulative predation pressure, which indicates the importance of functional diversity as well as abundance. Farmers and agronomists can capitalise on the ecosystem services provided by carabid beetles by adapting agronomic practices and crop rotation to maintain a rich fauna of seed-eating carabids in fields and potentially across the agricultural landscapes. When integrated with rotational management practices, this ecosystem services can improve the efficiency of weed management and contribute to the sustainability of cropping systems.

Avian-mediated pest control is a significant ecosystem service with important economic implications. However, there is an overall paucity of experimental information about how landscape simplification affect its current level. Information on pest control by birds is missing in some permanent agroecosystems of worldwide importance, like olive orchards, that dominate vast areas in the Mediterranean region. We assess the effectiveness of insectivorous birds for controlling the two main pest insects in olive orchards and explore the effects of landscape complexity and distance to semi-natural patches on avian insectivore abundance and pest control. For this, we combine bird surveys with field experiments (branch exclusions and pest plasticine models) at the regional scale. Landscape heterogeneity increased the abundance and richness of insectivorous birds, which were also more abundant and diverse in semi-natural patches, compared to the farm olive matrix. Experiments evidenced that pest control by birds (measured as attack rates to plasticine models and pest damage) in the studied olive orchards is negligible, while pests were overall abundant and pest damage was high on most farms. This raises alarms about the status of avian pest control in this agroecosystem. Although landscape heterogeneity increased the abundance/richness of insectivorous birds, and favored some forest species, insectivorous bird abundance seems diluted in relation to prey availability in all landscapes. Thus, pest control by birds seems currently unsuccessful in olive orchards. Our results might be evidencing the loss of an ecosystem service due to a generalized massive decline of common and forest insectivorous birds. Key messageO_LIOlive orchards dominate extensive areas causing important landscape simplification. C_LIO_LIInsectivorous birds are more abundant in semi-natural patches within olive farms. C_LIO_LIField experiments show a low impact of birds on olive pests and damage. C_LIO_LIAvian-mediated pest biocontrol seems diluted by limited suitable habitat for birds. C_LIO_LIAgri-environmental measures should focus on increasing landscape complexity. C_LI

Prairies, once spanning the Upper Midwest, have now largely been replaced by agriculture. The lack of resources available to pollinators in agricultural fields and practices commonly employed has led to a decline in insect diversity. To enhance sustainable practices, we must better understand how ecosystem services such as pest control and pollination services provided by a diverse insect and pollinator community scale to current farming practices as related to crop yield and how landscape features may positively contribute to insect and pollinator diversity. We examined how landscape heterogeneity relates to insect and pollinator diversity, as well as how insect and pollinator diversity relates to crop yield across common farming practices. We planted 35 single acre sites of Brassica carinata, a generalist flower possibly capable of supporting a diverse insect community. We randomly assigned each site with a combination of three common farming practices: tilling (yes/no), added honey bee hives (yes/no), and treatment with systemic neonicotinoids (yes/no). Insect and pollinator diversity and the surrounding landscape at multiple spatial scales were calculated. We observed a significant positive relationship between insect (and pollinator) diversity with yield in the absence of any farming practice. All farming practices will increase yield. However, farming practices alter the relationship between yield and diversity. The addition of seed treatment or tillage negates the relationship between insect (and pollinator) diversity with yield. Seed treatment alone results in a flat relationship between diversity and yield for all insects and a negative relationship for pollinators. Increased landscape heterogeneity results in a positive relationship between insect diversity at the 1000 m scale and pollinator diversity at the 3000 m scale, suggesting large-scale heterogeneity contributes to overall insect diversity. Our results show that increasing large-scale landscape heterogeneity increases diversity serving as a substitute for common farming practices such as application of pesticides, tilling, or bee hives. Increased heterogeneity could save farmers from the input cost of treatment or tillage, by way of increased insect diversity, while still providing similar yields.

Agricultural management recommendations based on short-term studies can produce findings inconsistent with long-term reality. Here, we test the long-term relative profitability and environmental sustainability of continuous no-till agriculture practices on crop yield, soil moisture, and N2O fluxes. Using a moving window approach, we investigate the development and stability of several attributes of continuous no-till as compared to conventional till agriculture over a 29-year period at a site in the upper Midwest, U.S. We find that over a decade is needed to detect the consistent benefits of no-till on important attributes at this site. Both crop yield and soil moisture required periods 15 years or longer to generate patterns consistent with 29-year trends. Only marginally significant trends for N2O fluxes appeared in this period. Importantly, significant but misleading short-term trends appeared in more than 20% of the periods examined. Relative profitability analysis suggests that 10 years after initial implementation, 86% of periods recuperated the initial expense of no-till implementation, with the probability of higher relative profit increasing with longevity. Results underscore the essential importance of decade and longer studies for revealing the long-term dynamics and emergent outcomes of agricultural practices for different sustainability attributes and are consistent with recommendations to support the long-term adoption of no-till management.\n\nGRAPHICAL ABSTRACT\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=187 SRC=\"FIGDIR/small/788240v1_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (42K):\norg.highwire.dtl.DTLVardef@1e7529eorg.highwire.dtl.DTLVardef@1e11268org.highwire.dtl.DTLVardef@17f8995org.highwire.dtl.DTLVardef@2196fe_HPS_FORMAT_FIGEXP M_FIG C_FIG HIGHLIGHTSO_LIWe test long-term effects of no-till on yield, soil moisture, and N2O fluxes\nC_LIO_LIWe examine 29 years of data with a moving window and relative profitability method\nC_LIO_LIIt takes at least a decade to detect consistent benefits of no-till\nC_LIO_LIShorter studies can produce significant but misleading findings\nC_LIO_LILong studies are essential to reveal the dynamics of agricultural management\nC_LI

O_LIUnderstanding effects on the huge diversity of cropping systems on local biodiversity is challenging but necessary to implement agroecological systems. Through a functional approach, the translation of cropping systems into resource and disturbance gradients is promising to decipher the relationship between cropping systems and biodiversity but has never been implemented for arthropods. C_LIO_LITo investigate contributions of resource and disturbance gradients arising from cropping systems vs environmental context (regional effect, meteorological conditions and landscape characteristics) on beneficial arthropod communities, we used a dataset collected in 60 crop fields from three French areas over a five-years period. It includes all farmers interventions, crop sequences, meteorological data, landscape composition and carabid samplings. C_LIO_LIWe found that the environmental context contributed to about 75% of explained carabid variations on average, while resource and disturbance gradients contributed to about 25% of explained carabid variations. The resource and disturbance gradients were particularly important in winter and spring preceding the spring-summer period to determine carabid variations. C_LIO_LIMoreover, we identified thresholds above which resource and disturbance gradients start being beneficial or detrimental for carabids. For example, a Treatment Frequency Index above 2.07 in spring decreased the total activity density of carabids during the spring-summer period. C_LIO_LISynthesis and application. While implementing for the first time a functional approach to understand the effects of different facets of cropping systems on arthropods, our study also allows us to identify periods and thresholds above which specific practices affect carabids. The identification of such thresholds can guide the provision of recommendations for policy, stakeholders and farmers about how to reduce cropping systems impact on arthropods. C_LI

Brassica carinata is a biofuel and animal feed crop with expanding global production. Although there is much research on common farming practices to improve yield, there is almost a complete absence of data on the dependency of yield through pollination services. Reciprocally, we lack information on whether B. carinata offers ecosystem services to pollinators. We observed almost 4000 pollinator visits, quantified different plant functional traits, including floral resources and examined the effect of supplementing fields with honey bee hives and the use of neonicotinoid seed treatment on seed yield and honey bee health. Data was collected from 35 0.404-ha sites with more than 800 focal B. carinata individuals across 2 years in the Prairie Coteau region of the Northern Great Plains. We found that pollinators (n = 28 species) are attracted to floral resources at different spatial scales. High visitation rates by pollinator species were associated with double the seed set in B. carinata relative to the lowest visitation rates. Brassica carinata adds floral resources to the agricultural ecosystem and therefore has the potential to increase pollinator health. However, species interactions are influenced by the use of insecticides and the presence of honey bees by managed beehives. In particular, insecticides alter the role of pollinators on crop pollination by reducing the positive impact of floral resources on pollinator-mediated yield and honey bee health.

Conventional tillage (i.e. plowing) is often associated with soil degradation and a loss of biodiversity. In response, reduced tillage has increasingly been promoted as a sustainable alternative for its positive impacts on soil structure, water dynamics, and biodiversity. However, reduced tillage not only favors beneficial soil-dwelling organisms, but also pests. In this field study, we examined the effects of five years of reduced tillage on the physical properties of the soil and the dynamics of Agriotes wireworm populations (Elateridae), which are increasingly widespread pests. Our results show that tillage reduction led to stable edaphic conditions and a redistribution of organic matter, creating a favorable environment for wireworms. While our results demonstrate the beneficial effects of reduced tillage on aggregate stability, they also indicate a concomitant increase in soil bulk density, suggesting a reduction in water-holding capacity. Monitoring of wireworm populations revealed their aggregated distribution and their increase in abundance in infested areas year on year. Monitoring soil moisture revealed that tillage reduction improved water dynamics, enhancing infiltration and reducing evaporation. This could potentially favor the development of wireworms. Surprisingly, wireworm size distribution showed a higher proportion of young instars in plowed plots, evidencing that, firstly, the lack of soil cover does not prevent oviposition and that injury caused by plowing targets more the last instars rather than young larvae. While reduced tillage improves key soil health indicators, our findings suggest a potential trade-off in terms of increased pest pressure. Our study highlights the importance of adopting a holistic approach when designing sustainable cropping systems, as well as considering the services and dis-services they provide.

Knowledge of the specific insect densities during crop development is necessary to perform appropriate measures for the control of insect pests and to minimize yield losses. In a previous study, both spatial and temporal approaches were adopted to analyse the influence of landscape structure and field variables on herbivore and predatory insects on maize. Both types of variables influenced insect abundance, but the highest effect was found with maize phenology. Given that the field planting date could modulate the influence produced by the structure of the landscape on herbivores and predatory insects, analyses of population dynamics must be performed at both the local and landscape levels. The anterior prompted us to study these aspects in the two common planting periods (early and late) in northern Spain. The present study tests the hypothesis that the period of maize planting could have a higher effect than phenology or interannual variation on the abundance of natural enemies and herbivores on maize. Our results showed that only the abundances of other herbivore thrips and Syrphidae were significantly different between the two planting periods. Moreover, we found significant effects of planting period when we performed yearly analysis in 2015 for Coccinellidae and Chrysopidae and in 2016 and 2017 for Aeolothrips sp. Most of the taxa had abundance peaks in earlier growth stages, which are related to pollination (before or during), while only Stethorus punctillum and Syrphidae increased later in the season. Furthermore, Frankliniella occidentalis, aphids, Syrphidae and Coccinellidae registered higher abundances in fields sown in the late planting period than in the rest of the insect species. The results of the present study highlight the effects of sowing dates on insect dynamics in maize. HighlightsO_LIHerbivorous and natural enemy abundance peaks in earlier growth stages. C_LIO_LIAbundance of thrip and Syrphidae were different between the two planting periods. C_LIO_LIAbundance of Coccinellidae, Chrysopidae and Aeolothrips sp. was different when performed yearly analysis. C_LI

Arthropods deliver vital ecosystem services in agricultural landscapes, but their diversity is threatened by intensified farming and landscape simplification. Despite this, the relative impacts of farming practices at the landscape level remain underexplored compared to local and land cover effects. In this study, we dissect the influence of local and landscape factors, including farming practices, on arthropod communities. By sampling 18 grasslands in northeastern France during spring and autumn 2021, we collected 14 arthropod families, identifying all species of carabids and spiders. We conducted surveys of farming practices to estimate their intensity at landscape level. Our results highlight that environmental factors affect arthropod communities differently between seasons. Intensity of farming practices at landscape level was less explanatory of arthropod communities, but this impact is additional to that of local conditions and land cover. Our study underscores the critical need to integrate farming practices into landscape-level management strategies to safeguard arthropod diversity.

Sowing grass seeds generally supports the rapid development of a closed perennial vegetation, which makes the method universally suitable for fast and effective landscape-scale restoration of grasslands. However, sustaining the recovered grasslands, and increasing their diversity is a challenging task. Understanding the role of seed bank compositional changes and vegetation dynamics contributes to designating management regimes that support the establishment of target species and suppress weeds. Our aim was to reveal the effect of post-restoration management on the vegetation and seed bank dynamics in grasslands restored in one of the largest European landscape-scale restoration projects. Eight years after restoration we sampled the vegetation and seed bank in a total of 96 plots located in 12 recovered grasslands in the Great Hungarian Plain. In each recovered grassland stand we designated a mown (mown from Year 1 to Year 8) and an abandoned sample site (mown from Year 1 to Year 3 then abandoned from Year 4 to Year 8). Mown and abandoned sites showed divergent vegetation and seed bank development. Abandonment led to the decline of sown grasses and higher cover of weeds, especially in the alkaline grasslands. Our study confirmed that seed bank has a limited contribution to the maintenance of biodiversity in both grassland types. We found that five years of abandonment had a larger effect on the seed bank than on the vegetation. We stress that long-term management is crucial for controlling the emergence of the weeds from their dense seed bank in restored grasslands. Implications for practiceO_LISeed sowing of grass mixtures can be a feasible tool for restoring grasslands at large scales. However, the developed vegetation usually has low biodiversity and a high seed density of weeds is typical in the soil seed bank even several years after the restoration. Therefore, post-restoration management is necessary for suppressing weeds both aboveground and belowground. C_LIO_LIWe recommend to design the long-term management of the sites subjected to grassland restoration already in the planning phase of the restoration projects and ensure that the management plan is ecologically and economically feasible. C_LIO_LIWe recommend to complement the monitoring of vegetation with the analysis of soil seed bank for evaluating restoration success. C_LI

BackgroundGrasslands occupy significant land area and account for a large proportion of the global soil carbon stock, yet the direct effects of grazing and genotypic composition on relationships between shoot and root production are poorly resolved. This lack of understanding hinders the development of models for predicting root production in managed grasslands, a critical variable for determining soil carbon stocks.\n\nMethodsWe quantified the effects of season-long defoliation treatments on both shoot and root production across four cultivars of a widely-planted pasture grass species (Paspalum notatum Fluegge) in a common garden setting in South Florida, USA.\n\nResultsWe found that infrequently applied (4 week) severe defoliation (to 5 cm) substantially enhanced shoot production for all cultivars, while severe defoliation reduced root production across cultivars, regardless of frequency. Overall, cultivars varied substantially in root production across the range of defoliation treatments in our study. However, there was no significant relationship between shoot and root production.\n\nConclusionsOur results find that aboveground and belowground productivity are only weakly coupled, suggesting caution against use of simple aboveground proxies to predict variations in root production in grasslands. More broadly, our results demonstrate that improved modeling and management of grasslands for belowground ecosystem services, including soil carbon sequestration/stocks, will need to account for intraspecific genetic variations and responses to defoliation management.

Reducing reliance on pesticides is an important global challenge. With increasing constraints on their use, in recent years there has been a declining trend in pesticide use for arable crops in the UK. But with increasing disease pressures and global demand for food, there is a greater need for effective measures of pest and disease control. These circumstances highlight the need for widespread adoption of sustainable alternative control measures. Integrated Pest Management (IPM) is one such solution, comprising a set of management strategies which focus on the long-term prevention, detection and control of pests, weeds and diseases. While many of these methods are acknowledged to offer effective control, their implementation has thus far been limited in practice. As a case study we considered Septoria tritici blotch (STB) (Zymoseptoria tritici), an economically important disease of wheat. We used epidemiological modelling techniques to investigate the potential of different IPM control strategies (crop residue burial, delayed sowing, variety mixtures and biocontrols). Combining existing data with a deterministic, compartmental infectious disease model of STB transmission, we simulated the implementation of an IPM regime into the STB disease system. We investigated the outcomes on disease prevalence and crop yield when comparing conventional and IPM control regimes. In a single field, for the individual implementation of IPM measures we found the starkest difference in potential yield outcomes between delayed sowing and biocontrols (greatest yields), and crop residue burial and variety mixtures (lowest yields). We also found that the collective use of IPM measures has the potential to offer individual growers comparable control to a standard fungicide regime. For a multi-field setting, representing a community of crop growers, a high proportion of growers using IPM can reduce the level of external infection incurred by the growers who maintain a fungicide regime. Author SummaryWith the UK Government seeking to reduce the environmental risk posed by pesticides, the agricultural industry is under increasing pressure to explore alternative methods of disease control. One such alternative method is Integrated Pest Management (IPM), which consists of a variety of management strategies for long-term prevention, detection and control of crop diseases. In our study, we simulate the potential outcomes of using IPM for the control of Septoria tritici blotch, a common disease of wheat. Our results suggest that a regime of IPM control methods may offer growers comparable yields and disease control to conventional fungicide treatments. Furthermore, in a wider system of crop growers, a higher proportion using IPM can reduce the level of infection incurred by all growers in the system, including those who do not use IPM. These findings can offer insight to crop growers who are considering the use of IPM, and to policy-makers who are interested in encouraging its uptake, by validating and quantifying its effectiveness relative to current standard practices.

Permanent grassland (PG) is an important agricultural land use for the delivery of multiple ecosystem services (ES), including carbon sequestration, water quality protection, food production, habitat provision, and cultural activities. However, PG environments are threatened by sub-optimal management, cultivation, and abandonment that are influenced by context, land managers attitudes and societal demand for ES. Therefore, the perceptions and attitudes of key decision-makers (farmers) and other stakeholders (non-farmers, including citizens and consumers of the products of permanent grasslands, and ES) need to be understood to ensure the sustainability of PGs and the ES they provide. A systematic review of the literature identified 135 scholarly articles. Application of thematic analysis, allowed the organization, and synthesis of current research related to (different) stakeholder attitudes, and how these influence PG management and the delivery of ES. The results suggest that different stakeholders hold different views towards permanent grassland, with farmers in particular having to balance economic with other (potentially conflicting) drivers. The types of knowledge held by different groups of stakeholders, access to sources of information, as well as the influence of knowledge on behaviour; and environmental values (for example in relation to aesthetics or conservation of biodiversity) explained why certain motivations for attitudes and behaviours are held. A major gap, however, was identified in relation to PG as opposed to other types of landscape.

Cover cropping is considered a valuable tool for integrated weed management. However, weed suppression by cover crops can be inconsistent. We hypothesized that a native cover crop species may have greater capacity to suppress weeds than an introduced species owing to adaptive advantages. A study was conducted from 2020 to 2022 in a newly-established Autumn King tablegrape vineyard in Parlier, CA. Two cover crop treatments, a native plant species, phacelia (Phacelia tanacetifolia), or an introduced species, rye (Secale cereale L. Merced), were compared to a no cover crop, herbicide-managed control for impacts on weed control. Cover crops were sown in 2019 in the center 1.8 m of the 3.6 m space between the grapevine rows. The experimental design was a randomized complete block with four replications. Percent cover, weed density, and weed biomass in different seasons were assessed in the inter-row spaces and the vine rows. Soil samples were collected in 2021 from the grape row and interrow spaces to assess the weed seedbank. After the cover crops were terminated, percent weed cover was lower in the interrow of the phacelia compared to the no cover crop plots at two sampling times. When cover crops were actively growing (winter/spring), phacelia plots had a 7-fold higher cover crop to weed biomass ratio compared to that of the rye plots, thus indicating greater weed suppression. However, weed seedling emergence from the seedbank samples of the cover crop plots were 2- to 4-fold greater (in the phacelia and rye, respectively) than from the no cover crop plots. In summary, phacelia suppressed weeds more than rye; however, they both resulted in a bigger weed seedbank size compared to the herbicide-managed no cover crop plots, so additional management practices will be needed for long term weed management with cover crops in vineyards.

One of the UNs 17 Sustainable Development Goals is a world free from hunger, with sustainable food production and resilient agricultural practices (SDG 2). However, as we approach the 2030 deadline, global food security, a multidimensional challenge, remains unsolved. With a growing human population, food demand will likely increase, leading to more intensive agricultural practices that put bees and their pollination services at risk. Conserving bees is, thus, crucial to ensuring our food security. A promising solution is cultivating floral plantings alongside crops, which can enhance ecosystem services such as pollination. However, floral plantings may also compete with crops for bees. To optimize their benefits, we need to understand when floral plantings facilitate bee spillover to crops, supporting both bee conservation and agricultural productivity. To address this, we synthesized existing knowledge using a research weaving approach, which combines bibliometric and systematic mapping. Our synthesis suggests that the effects of floral plantings result from a complex interplay of factors, including crop type, bee species, floral planting composition, and environmental conditions. To clarify this interplay, we propose an integrative hypothesis to guide future studies. Finally, our results highlight the need for stronger collaboration among researchers to better understand the role of floral plantings in ecological intensification.

Widespread declines in insect biomass and biodiversity have raised concerns about the sustainability of ecosystem services in agroecosystems. Ground-dwelling generalist predators such as carabids (Carabidae) and spiders (Araneae) are key contributors to natural pest control, yet their populations are threatened by modern farming practices. Organic mulching - a practice that increases within-crop habitat diversity - has been proposed as a means to support beneficial arthropod communities while also delivering agronomic benefits. This study investigated the eEects of diEerent organic mulches (triticale/vetch, straw, grass silage) on carabid and spider communities in three large-scale, replicated field trials in potato fields in central Germany. Arthropods were sampled using pitfall traps during and after the growing season, with additional traps used to assess potential sampling biases related to mulch presence. Community composition, species-specific responses, and potential carry-over eEects into the following year were analysed using a combination of generalised linear mixed models, diversity indices, ordination methods, and indicator species analysis. Across the trials, 12,076 adult carabids (42 taxa) and 2,399 spiders (38 taxa) were collected, enabling robust analysis of treatment eEects on community composition and species-specific responses. The results showed that organic mulching, particularly with triticale/vetch, significantly increased the abundance of several carabid (Bembidion lampros, B. quadrimaculatum, Poecilus cupreus) and Linyphiidae spider (Erigone atra, E. dentipalpis, Agyneta rurestris) species, and altered overall community composition. Species richness tended to be higher in mulched plots, though eEects on diversity indices were less consistent. However, positive impacts on predator populations were largely restricted to the potato growing season, with no evidence of persistent carry-over eEects into the subsequent year. The study discusses habitat complexity, microclimate moderation, and changes in prey availability as likely mechanisms underlying these patterns.

Abundance and distribution of earthworms in agricultural fields is frequently proposed as a measure of soil quality assuming that observed patterns of abundance are in response to improved or degraded environmental conditions. However, it is not clear that earthworm abundances can be directly related to their edaphic environment, as noted in Darwins final publication, perhaps limiting or restricting their value as indicators of ecological quality in any given field. We present results from a spatially explicit intensive survey of pastures within United Kingdom farms, looking for the main drivers of earthworm density at a range of scales. When describing spatial variability of earthworm abundance within any given field, the best predictor was earthworm abundance itself within 20 - 30 m of the sampling point; there were no consistent environmental correlates with earthworm numbers, suggesting that biological factors (e.g. colonisation rate, competition, predation, parasitism) drive or at least significantly modify earthworm distributions at this spatial level. However, at the national scale, earthworm abundance is well predicted by soil nitrate levels, density, temperature and moisture content, albeit not in a simple linear fashion. This suggests that although land can be managed at the farm scale to promote earthworm abundance and the resulting soil processes that deliver ecosystem services, within a field, earthworm distributions will remain patchy. The divergence in the interpretative value of earthworm abundance as an ecological indicator is a function of spatial scale, corresponding to species specific biological factors as well as a response to environmental pressures. Species abundance can effectively be used as ecological indicators, even if, at first, distributions seem random. However, care must be exercised, in the sampling design for the indicator species, if its abundance is to be used as a proxy for environmental quality at a particular scale (e.g. a management scale such as field scale).

Phosphorus (P) availability affects soil carbon (C) cycling such as microbial C use efficiency (CUE) and priming effects (PEs). While non-allophanic Andosols are characterized by high organic C content and strong P retention, the effects of different P fertilization regime on C dynamics in these soils remain poorly understood. In this study, we conducted a 20-day incubation experiment using 13C-enriched glucose to investigate how different soil P levels (Truog-P: 157 mg P kg-1 and 12 mg P kg-1) impacted microbial C dynamics in non-allophanic Andosols from contrasting field management practices. Our results showed that soil organic matter (SOM) priming is associated with P fertilization management, with total primed CO2-C emissions remaining low in these soils. In the high-P soils, glucose and nitrogen (N) addition resulted in negative PEs, whereas in the low-P soils, the same treatment stimulated microbial SOM mining, resulting in positive PEs. Additionally, higher glucose-derived CUE was found in the high-P soils than in low-P soils after 20 days of incubation. These findings suggest that long-term P fertilization influences both substrate-induced microbial assimilation and SOM decomposition, with P limitation potentially promoting SOM mining which, along with concurrent soil acidity and exchangeable Al toxicity, modulates CUE. This study provides insights for improving C sequestration in non-allophanic Andosols through soil fertility management.