Population declines of a widespread amphibian in agricultural landscapes

Modern agricultural practices are suspected to play a major role in the ongoing erosion of biodiversity. In order to assess whether this biodiversity loss is linked to past habitat modifications (e.g. land consolidation) or to current consequences of modern agriculture (e.g. use of agrochemicals), it remains essential to monitor species that have persisted in agricultural landscapes to date. In this study, we assessed the presence, abundance and recent population trends of one such species, the spined toad (Bufo spinosus) along a gradient of habitats from preserved (forests) to highly agricultural sites in rural Western France. Our results showed that both presence and abundance of spined toads were markedly lower in reproductive ponds surrounded by intensive agriculture. The most salient result of our study is the ongoing decline of this species in farmland habitats. Indeed, this result suggests that unknown factors are currently affecting a widespread terrestrial amphibian previously thought to persist in agricultural landscapes. These factors have recently induced strong population declines over the course of a few years. Future investigations are required to identify these factors at a time when anthropogenic activities are currently leading to unprecedented rates of biodiversity loss.

Optimizing potassium and nitrogen fertilizer strategies to mitigate greenhouse gas emissions in global agroecosystems

The efficient management of fertilizer application in agriculture is vital for both food security and mitigating greenhouse gas (GHG) emissions. However, as potassium fertilizer (KF) is an essential soil nutrient, its impact on soil GHG emissions has received little attention. To address this knowledge gap and identify key determinants of GHG emissions, we conducted a comprehensive meta-analysis of 205 independent experiments conducted worldwide. Our results revealed that, in comparison to sole nitrogen fertilizer (NF) application, the concurrent use of KF elevated nitrous oxide (N2O) and methane (CH4) emissions by 39.5 % and 21.1 %, respectively, while concurrently reducing carbon dioxide (CO2) emissions by 8.1 %. The ratio of nitrogen and potassium fertilizer input (NF/KF) is identified as the primary factor explaining the variation in N2O emissions, whereas the type of KF plays a crucial role in determining CH4 and CO2 emissions. We observed a significant negative correlation between the NF/KF ratio and response ratios of N2O and CH4 emissions and a positive correlation with CO2 emissions response ratios. Furthermore, our findings indicate that when the NF/KF ratio surpasses 1.97, 4.61, and 3.78, respectively, the impact of KF on reducing N2O, CH4, and CO2 emissions stabilizes. Overall, our results underscore that the global integration of KF into agricultural practices significantly influences N2O and CH4 emissions, while simultaneously reducing CO2 emissions at a large scale. These findings provide a foundational framework and practical guidance for optimizing fertilizer application in the development of GHG emission reduction models.

Assessing a potential conflict associated with the production of Moringa oleifera in the Limpopo Province of South Africa: A systems thinking approach

The increased movement of humans throughout the world allowed the transportation of several species, such as Moringa oleifera Lam. (moringa), into biomes far away from their native habitation. Native to India, moringa is a versatile, drought-tolerant, and fast-growing tree that is easily adaptable to wide-ranging tropical and sub-tropical conditions around the world. It is used in cosmetics, as food and medicine for humans, livestock feed, crop biostimulant, and green manure. Even though moringa is an alien species to South Africa, its production is increasing, and its numerous uses are recognised by communities. Moringa forms part of a highly complex (social, ecological, and economic) system. This is because it is on the Species Under Surveillance for Possible Eradication or Containment Targets (SUSPECT) list under the National Environmental Management Biodiversity Act (NEM:BA) of South Africa. Listing species that are regarded as beneficial to communities on national regulations can cause conflicts and uncertainties among various stakeholders (i.e., environmental policymakers, farmers, rural communities, and government bodies). In this paper, a systems thinking approach was applied to address complex and conflicting issues linked to the production and overall status (economic, ecological, legal, and social) of moringa in South Africa. The Causal Loop Diagram (CLD) was developed to present a broad insight into the complexity of moringa in South Africa and assist in underscoring the feedback mechanisms within the system. Moreover, the CLD indicated that the position of moringa within the country comprised a variety of interdependent variables of government policies, environment, and society, which are interconnected into a multifaceted system. The potential conflict dimensions and types associated with allocating moringa an impact category within the South African context were identified, and this may serve as a useful tool for facilitating engagements and decision-making processes among stakeholders in resolving the status of moringa in South Africa.

Virome analysis of irrigation water sources provides extensive insights into the diversity and distribution of plant viruses in agroecosystems

Plant viruses pose a significant threat to agriculture. Several are stable outside their hosts, can enter water bodies and remain infective for prolonged periods of time. Even though the quality of irrigation water is of increasing importance in the context of plant health, the presence of plant viruses in irrigation waters is understudied. In this study, we conducted a large-scale high-throughput sequencing (HTS)-based virome analysis of irrigation and surface water sources to obtain complete information about the abundance and diversity of plant viruses in such waters. We detected nucleic acids of plant viruses from 20 families, discovered several novel plant viruses from economically important taxa, like Tobamovirus and observed the influence of the water source on the present virome. By comparing viromes of water and surrounding plants, we observed presence of plant viruses in both compartments, especially in cases of large-scale outbreaks, such as that of tomato mosaic virus. Moreover, we demonstrated that water virome data can extensively inform us about the distribution and diversity of plant viruses for which only limited information is available from plants. Overall, the results of the study provided extensive insights into the virome of irrigation waters from the perspective of plant health. It also suggested that an HTS-based water virome surveillance system could be used to detect potential plant disease outbreaks and to survey the distribution and diversity of plant viruses in the ecosystem.

Allelopathy and allelobiosis: efficient and economical alternatives in agroecosystems

Chemical interactions in plants often involve plant allelopathy and allelobiosis. Allelopathy is an ecological phenomenon leading to interference among organisms, while allelobiosis is the transmission of information among organisms. Crop failures and low yields caused by inappropriate management can be related to both allelopathy and allelobiosis. Therefore, research on these two phenomena and the role of chemical substances in both processes will help us to understand and upgrade agroecosystems. In this review, substances involved in allelopathy and allelobiosis in plants are summarized. The influence of environmental factors on the generation and spread of these substances is discussed, and relationships between allelopathy and allelobiosis in interspecific, intraspecific, plant-micro-organism, plant-insect, and mechanisms, are summarized. Furthermore, recent results on allelopathy and allelobiosis in agroecosystem are summarized and will provide a reference for the future application of allelopathy and allelobiosis in agroecosystem.

Oligotrophic microbes are recruited to resist multiple global change factors in agricultural subsoils

An increasing number of anthropogenic pressures can have negative effects on biodiversity and ecosystem functioning. However, our understanding of how soil microbial communities and functions in response to multiple global change factors (GCFs) is still incomplete, particularly in less frequently disturbed subsoils. In this study, we examined the impact of different levels of GCFs (0-9) on soil functions and bacterial communities in both topsoils (0-20 cm) and subsoils (20-40 cm) of an agricultural ecosystem, and characterized the intrinsic factors influencing community resistance based on microbial life history strategy. Our experimental results showed a decline in soil multifunctionality, bacterial diversity, and community resistance as the number of GCFs increased, with a more drastic reduction in community resistance of subsoils. Specifically, we observed a significantly positive relationship between the oligotroph/copiotroph ratio and community resistance in subsoils, which was also verified by the negative correlation between 16S rRNA operon (rrn) copy number and community resistance. Structural equation modeling further revealed the direct effects of community resistance in promoting the ecosystem functioning, regardless of top- and subsoils. Therefore, these results suggested that subsoils may recruit more oligotrophic microbes to enhance their originally weaker community resistance under multiple GCFs, which was essential for maintaining sustainable agroecological functions and services. Overall, our study represents a significant advance in linking microbial life history strategy to the resistance of belowground microbial community and functionality.

Use of the term "landscape" in sustainable agriculture research: A literature review

Finding consensus in definitions of commonly-used terms and concepts is a key requirement to enable cooperations between interdisciplinary scientists and practitioners in inter- or transdisciplinary projects. In research on sustainable agriculture, the term 'landscape' is emphasised in particular, being used in studies that range from biogeochemical to socio-economic topics. However, it is normally used in a rather unspecific manner. Moreover, different disciplines assign deviating meanings to this term, which impedes interdisciplinary understanding and synthesis. To close this gap, a systematic literature review from relevant disciplines was conducted to identify a common understanding of the term "landscape". Three general categories of landscape conceptualizations were identified. In a small subset of studies, "landscape" is defined by area size or by natural or anthropogenic borders. The majority of reviewed papers, though, define landscapes as sets of relationships between various elements. Selection of respective elements differed widely depending on research objects. Based on these findings, a new definition of landscape is proposed, which can be operationalized by interdisciplinary researchers to define a common study object and which allows for sufficient flexibility depending on specific research questions. It also avoids over-emphasis on specific spatio-temporal relations at the "landscape scale", which may be context-dependent. Agricultural landscape research demands for study-specific definitions which should be meticulously provided in the future.

Soil Bacterial Communities Across Seven Rhizoma Peanut Cultivars (Arachis glabrata Benth.) Respond to Seasonal Variation

Soil microorganisms play key roles in soil nutrient transformations and have a notable effect on plant growth and health. Different plant genotypes can shape soil microbial patterns via the secretion of root exudates and volatiles, but it is uncertain how a difference in soil microorganisms induced by crop cultivars will respond to short-term seasonal variations. A field experiment was conducted to assess the changes in soil bacterial communities of seven rhizoma peanut (Arachis glabrata Benth, RP) cultivars across two growing seasons, April (Spring season) and October (Fall season). Soils' bacterial communities were targeted using 16S rRNA gene amplicon sequencing. Bacterial community diversity and taxonomic composition among rhizoma peanut cultivars were significantly affected by seasons, cultivars, and their interactions (p < 0.05). Alpha diversity, as estimated by the OTU richness and Simpson index, was around onefold decrease in October than in April across most of the RP cultivars, while the soils from Arblick and Latitude had around one time higher alpha diversity in both seasons compared with other cultivars. Beta diversity differed significantly in April (R = 0.073, p < 0.01) and October (R = 0.084, p < 0.01) across seven cultivars. Bacterial dominant taxa (at phylum and genus level) were strongly affected by seasons and varied towards more dominant groups that have functional potentials involved in nutrient cycling from April to October. A large shift in water availability induced by season variations in addition to host cultivar's effects can explain the observed patterns in diversity, composition, and co-occurrence of bacterial taxa. Overall, our results demonstrate an overriding effect of short-term seasonal variations on soil bacterial communities associated with different crop cultivars. The findings suggest that season-induced shifts in environmental conditions could exert stronger impacts on soil microorganisms than the finer-scale rhizosphere effect from crop cultivars, and consequently influence largely microbe-mediated soil processes and crop health in agricultural ecosystems.

Plastic mulching, and occurrence, incorporation, degradation, and impacts of polyethylene microplastics in agroecosystems

Polyethylene microplastics have been detected in farmland soil, irrigation water, and soil organisms in agroecosystems, while plastic mulching is suggested as a crucial source of microplastic pollution in the agroecosystem. Plastic mulch can be broken down from plastic mulch debris to microplastics through environmental aging and degradation process in farmlands, and the colonization of polyethylene-degrading microorganisms on polyethylene microplastics can eventually enzymatically depolymerize the polyethylene molecular chains with CO2 release through the tricarboxylic acid cycle. The selective colonization of microplastics by soil microorganisms can cause changes in soil microbial community composition, and it can consequently elicit changes in enzyme activities and nutrient element content in the soil. The biological uptake of polyethylene microplastics and the associated disturbance of energy investment are the main mechanisms impacting soil-dwelling animal development and behavior. As polyethylene microplastics are highly hydrophobic, their presence among soil particles can contribute to soil water repellency and influence soil water availability. Polyethylene microplastics have been shown to cause impacts on crop plant growth, as manifested by the effects of polyethylene microplastics on soil properties and soil biota in the agroecosystems. This review reveals the degradation process, biological impacts, and associated mechanisms of polyethylene microplastics in agroecosystems and could be a critical reference for their risk assessment and management.

Atmospheric transport of particulate matter and particulate-bound agrochemicals from beef cattle feedlots: Human health implications for downwind agricultural communities

Beef cattle feedlot particulate matter (PM) is a complex mixture of dust, animal waste, agrochemicals, and bioaerosols. However, no empirical data exist quantifying downwind residential exposure to PM or PM-bound agrochemicals. In the current study, authors investigated transport of PM and co-occurring insecticides and anthelmintics downwind of three feedlots in the Southern Great Plains (SGP) of North America from May-August 2022. PM collected on total suspended particulate (TSP) filters was analyzed via UHPLC-MS/MS for six pyrethroids and five macrocyclic lactones (MLs). Downwind TSP concentrations rapidly declined from 0.01 to ≤1.6 km (Monte Carlo mean ± SEM; 5049 ± 96.1 μg/m³) and stabilized >1.6-12.4 km (1791 ± 9.9; μg/m³). Distance decay >1.6 km indicated downwind PM exceeded levels of safe human exposure during diurnal peak periods. Pyrethroids and MLs were detected >LOQ in 96.2 and 98.1 % of downwind samples. Screening-level cumulative residential exposure indicates elevated pyrethroid risk (LOC = 1; RI = 0.173) to rural children (1-2 yrs) living near cropland operations in the SGP, with disproportionate co-exposure to feedlot PM and legacy pollution in low-income, Hispanic and Latino communities. Frequent occurrence and sustained transport of pyrethroids downwind of feedlots facilitate residue accumulation in outdoor residential areas that must also be quantified to assess the magnitude of daily average and lifetime-adjusted oral and dermal exposure in surrounding communities. Results significantly expand the known distribution of feedlot-derived PM and agrochemicals and highlight human exposure pathways unrecognized in residential human health assessments supporting pesticide registration and feedlot risk evaluation.

Optimization of environmental and the other variables in the application of arbuscular mycorrhizal fungi as an ecotechnological tool for sustainable paddy cultivation: A critical review

Arbuscular Mycorrhizal Fungi (AMF) are effective natural alternatives to assist plants in improving crop productivity and immunity against pests and diseases. However, a comprehensive idea of the variables under which they show optimum activity, especially concerning particular soil, climate, geography, and crop characteristics, has yet to be adequately standardized. Since paddy is the staple food for half of the world's population, such standardization is highly significant globally. Research concerning determinants affecting AMF functioning in rice is limited. However, the identified variables include external variables such as abiotic, biotic, and anthropogenic factors and internal variables such as plant and AMF characteristics. Among the abiotic factors, edaphic factors like soil pH, phosphorus availability, and soil moisture significantly affect AMF functioning in rice. In addition, anthropogenic influences such as land use patterns, flooding, and fertilizer regimes also affect AMF communities in rice agroecosystems. The principal objective of the review was to analyse the existing literature on AMF concerning such variables generally and to assess the specific research requirements on variables affecting AMF in rice. The ultimate goal is to identify research gaps for applying AMF as a natural alternative in the sustainable agriculture of paddy with optimum AMF symbiosis enhancing rice productivity.

Detecting microplastics in organic-rich materials and their potential risks to earthworms in agroecosystems

Microplastics (MPs) are a major emerging contaminant in agroecosystems, due to their significant resistance to degradation in terrestrial environments. Although previous investigations have reported the harmful effects of MPs contamination on soil biological properties, still little is known about the characteristics and fate of MPs in biosolid-amended soils and their risks to soil biota, particularly earthworms. We determined microplastics' concentration, size distribution, and chemical composition in 3 sewage sludge biosolids and 6 biosolid-amended agricultural soils. In addition, we assessed the potential short-term risks of MPs to earthworms' (Amynthas Gracilis and Eisenia Fetida) survival rate and fitness in an environmentally relevant exposure study (28 days). Biosolid-amended soils (1000-3100 MPs kg^-1 dry mass) showed ≈30 times lower MPs content than investigated biosolids (55400-73800 MPs kg^-1 dry mass), with microplastic fragment to fibre ratios between 0.2 and 0.6 and 0.3-0.4 in soils and biosolids, respectively. Total MPs dry mass was also ≈19 times lower in assessed soils (12-26 mg kg^-1) than biosolids (328-440 mg kg^-1). On average 77% and 80% of plastic fragments had a lower dimension than 500 µm, while 50% and 67% of plastic fibres had a length of less than 1000 µm in soil and biosolid samples, respectively. Polyethylene (23.6%) was the major source of microplastic contamination in biosolid-amended soils, while polyethylene terephthalate (41.6%) showed the highest concentration in biosolid samples. Spiked polyethylene MPs did not show any significant effect on earthworms' survival rate (93-99%). However, biosolid application significantly (P < 0.05) decreased survival rate of Eisenia Fetida (81%) but showed no significant effect on Amynthas Gracilis (93%). Biosolid amendment significantly (P < 0.05) decreased earthworms' growth rate, with higher impact on Eisenia Fetida than Amynthas Gracilis, while there were no significant differences between control and microplastic spiked treatments. The overall decrease in MPs concentration of earthworm casts, compared with initial MPs concentrations in soil, indicated that the investigated species did not bioaccumulate MPs during the exposure experiment.

The Influence of Soil Organic Carbon and Climate Variability on Crop Yields in Kongwa District, Tanzania

This study assessed the influence of soil organic carbon (SOC) accumulation and climate variability on crop yields in Kongwa District, central Tanzania. In doing so, climate data and soil samples were collected from Mnyakongo and Ugogoni villages through soil sampling, interviews and surveys. Walkley-Black method, Mann-Kendall test, and MS Excel were used to analyze SOC, climate, crop yields respectively. The results exhibited that the accumulation of SOC was significantly greater in soils under organic fertilization (1.15 and 0.80 MgC ha^-1 at soil 0-20 cm and 20-30 cm depth) than under no-fertilization (0.35 and 0.30 MgC ha^-1 at 0-20 cm and 20-30 cm) and decreased with increasing soil depths. Under these two soil treatments, the average yields for maize, sorghum and millet were almost 1.8 tn ha^-1 under organic fertilization and 0.6 tn ha^-1 under no-fertilization. Specifically, maize yields ranged from 1.5 to 2.2 tn ha^-1, while both sorghum and millet had 1.1-1.7 tn ha^-1. Therefore, yields were significantly higher under organic fertilizations than under no-fertilizations. Besides, the mean annual rainfall or temperature (1980‒2020) fluctuated at a decreasing (R² = 0.21) or an increasing trend (R² = 0.30). Comparatively, the yields for maize, sorghum or millet fluctuated at a decreasing trend at R² = 0.07, 0.05, or 0.85, respectively. Correspondingly, it was found that the temporal increase in rainfall and temperature had positive (R² ~0.5) and negative (R² ~0.3) correlations with crop yields, respectively. In contrast, the decline in rain's intensity and frequency had negative impacts on crop yields. Thus, both SOC and climate correlated with crop yields.

Strengthening agroecological resilience through commons-based seed governance in the Philippines

The Filipino agricultural sector is exposed to multiple climatic, economic, and social risks that will likely intensify in the near future. Building agroecological resilience has been proposed to protect small-scale farmers' livelihoods and improve food security in the context of (unexpected) shocks and disruptions, and slow system changes such as climate change. This paper argues that commons-based seed production, based on collective management and ownership of seeds and varieties, can play a central role in building resilience capacities in smallholder communities. I explore this by applying an indicator-based framework to assess the contribution of the Filipino farmer network Magsasaka at Siyentipiko para sa Pag-unlad ng Agrikultura (MASIPAG) to agroecological resilience. I find that the networks' commons-based seed governance builds agroecological resilience in various ways. By equipping small-scale farmers with the tools to regain control over seed production and breeding, they become stewards of an actively evolving collection of varieties. The in situ maintenance and development of traditional, open-pollinated varieties and a network of diversified trial and backup farms build up buffering capacities and foster agrobiodiversity and local adaptation. A focus on regionally available natural resources reduces vulnerabilities to external factors. Adaptive capacities are strengthened through a high degree of flexibility and responsiveness achieved by self-organization and polycentric organizational structures. Broad participation, shared learning and spaces for experimentation support the development of farmers' capacities to respond to diverse challenges. Commons-based approaches to seed governance can thus strengthen agroecological resilience and long-term food security in smallholder agricultural systems.

A long-term field experiment confirms the necessity of improving biowaste sorting to decrease coarse microplastic inputs in compost amended soils

Microplastic (MP) input into agroecosystems is of particular concern as their sources are diverse (mulching films, biosolid application, wastewater irrigation, flooding, atmospheric input, road runoff). Compost application, which is needed to sustain soil ecosystem services in the context of a circular economy, may be a source of microplastics. The aim of this study was to evaluate how different composts derived from urban wastes impact the nature and quantity of coarse (2-5 mm) microplastics (CMP) in soils, using a long-term field experiment in France. Composts resulting from different levels of urban waste sorting were investigated. Our approach included the isolation of microplastics from composts and amended soils followed by their characterization using pyrolysis GC/MS spectrometry. We found that coarse microplastic concentrations varied from 26.9 to 417 kg per hectare depending on the compost type, after 22 years of bi-annual application. These values may be higher than for conventional agricultural practices, as application rate was twice as high as for normal practices. Composts made from municipal solid waste were by far the organic amendments leading to the highest quantity of plastic particles in soils, emphasizing the urgent need for limiting plastic use in packaging and for improving household biowaste sorting. Our results strongly suggest that standards regulating organic matter amendment application should take microplastics into account in order to prevent contamination of (agricultural) soils. Moreover, although no impacts on the soil bio-physico-chemical parameters has been noted so far. However, given the huge microplastic inputs, there is an urgent need to better evaluate their effect on soil functioning.

Long term effect of biochar on soil plant water relation and fine roots: Results after 10 years of vineyard experiment

Biochar is widely suggested to improve soil physical properties and soil-water-plant interactions. Furthermore, the application of biochar to the soil can alter the dynamics of the roots and, in turn, affect the performance of the plant. Nevertheless, the long-term evolution of these effects is unknown and of critical importance because biochar persists in soil for centuries. The results of this work are part of a long-term study in the vineyard started in 2009 and still ongoing. In this work, the effect of applying biochar to soil on the plant-water relationships of Vitis vinifera, soil properties and fine root traits is evaluated 10 years after application. Even after 10 years, the ecophysiological measurements indicated an increase in soil water content and a significant increase in the water status of the plants in the plots treated with biochar. Independently of the diameter class considered, both doses of biochar led in the entire 40 cm of soil to a general reduction of the fine-root standing biomass and length, which is probably due to the lower need for fine root foraging. Moreover, the SRL did not show differences among different treatments. When fine-root traits were analysed along the soil depth at 10 cm intervals, we noted that both length and biomass were significantly higher in the control plant only in the upper soil layers (20 cm) and SRL was significantly higher only in the upper 10 cm of soil. These findings underscore how control plants plastically respond to the lower content of water in the soil by decreasing the fine-root cost-to-benefit ratio, especially in the topsoil layer. Research on the effect of biochar in viticulture can provide an effective contribution to the mitigation of climate change by increasing the water status of the soil and plants even 10 years after its application.

Evidence of environmental transfer of tebuconazole to the eggs in the house sparrow (Passer domesticus): An experimental study

Triazole compounds are among the most widely used fungicides in agroecosystems to protect crops from potential fungal diseases. Many farmland birds spend a significant part of their life cycle in agroecosystems, which may chronically expose them to pesticides. We experimentally tested whether exposure to environmental concentrations of tebuconazole could induce a contamination of the eggs in an agroecosystem sentinel species, the house sparrow (Passer domesticus). Wild-caught adult sparrows were maintained in captivity and exposed (exposed group) or not (control group) for seven months to tebuconazole through drinking water. Eggs were opportunistically collected for the determination of tebuconazole concentration by Liquid Chromatography coupled to tandem Mass Spectrometry in eggs. We found that eggs from exposed parents all contained tebuconazole with a mean concentration of 1.52 ng g^-1 dry weight. In eggs from control parents, the tebuconazole concentration was below the limit of quantification (0.23 ng g^-1 dry weight) for 11 out of 13 eggs. Thus, our study demonstrates for the first time that environmental exposure of female birds to tebuconazole can translate into egg contamination by this fungicide.

Vegetation height and structure drive foraging habitat selection of the lesser kestrel (Falco naumanni) in intensive agricultural landscapes

Habitat selection in animals is a fundamental ecological process with key conservation implications. Assessing habitat selection in endangered species and populations occupying the extreme edges of their distribution range, or living in highly anthropized landscapes, may be of particular interest as it may provide hints to mechanisms promoting potential range expansions. We assessed second- and third-order foraging habitat selection in the northernmost European breeding population of the lesser kestrel (Falco naumanni), a migratory falcon of European conservation interest, by integrating results obtained from 411 direct observations with those gathered from nine GPS-tracked individuals. The study population breeds in the intensively cultivated Po Plain (northern Italy). Direct observations and GPS data coincide in showing that foraging lesser kestrels shifted their habitat preferences through the breeding cycle. They positively selected alfalfa and other non-irrigated crops during the early breeding season, while winter cereals were selected during the nestling-rearing phase. Maize was selected during the early breeding season, after sowing, but significantly avoided later. Overall, vegetation height emerged as the main predictor of foraging habitat selection, with birds preferring short vegetation, which is likely to maximise prey accessibility. Such a flexibility in foraging habitat selection according to spatio-temporal variation in the agricultural landscape determined by local crop management practices may have allowed the species to successfully thrive in one of the most intensively cultivated areas of Europe. In the southeastern Po Plain, the broad extent of hay and non-irrigated crops is possibly functioning as a surrogate habitat for the pseudo-steppe environment where most of the European breeding population is settled, fostering the northward expansion of the species in Europe. In intensive agricultural landscapes, the maintenance of alfalfa and winter cereals crops and an overall high crop heterogeneity (deriving from crop rotation) is fundamental to accommodate the ecological requirements of the species in different phases of its breeding cycle.

Experimental Exposure to Tebuconazole Affects Metabolism and Body Condition in a Passerine Bird, the House Sparrow (Passer domesticus)

Triazole compounds are among the most widely used fungicides in agroecosystems to protect crops from potential fungal diseases. Triazoles are suspected to have an impact on nontarget species due to their interactions with nonfungal sterol synthesis, and wild birds are likely to be contaminated by triazole fungicides because many of them live in agroecosystems. We experimentally tested whether exposure to environmental concentrations of a triazole could alter key integrative traits (metabolic rates and body condition) of an agroecosystem sentinel species, the house sparrow (Passer domesticus). Wild-caught adult sparrows were maintained in captivity and exposed (exposed group) or not (control group) for 7 continuous months to tebuconazole through drinking water. The metabolic rates of exposed and control sparrows were then measured at two different temperatures (12 °C and 25 °C), which correspond, respectively, to the thermoregulation and thermoneutrality temperatures of this species. We found that exposed sparrows had lower resting metabolic rates (i.e., measured at thermoneutrality, 25 °C) than controls. However, the thermoregulatory metabolic rates (i.e., measured at 12 °C) did not differ between exposed and control sparrows. Although the body mass and condition were not measured at the beginning of the exposure, sparrows at the time of the metabolic measurements 7 months after the onset of such exposure had a higher body condition than controls, supporting further the idea that tebuconazole affects metabolic functions. Our study demonstrates for the first time that the use of tebuconazole can alter metabolism and could potentially lead to adverse effects in birds. Environ Toxicol Chem 2022;41:2500-2511. © 2022 SETAC.

Quantifying exposure of bumblebee (Bombus spp.) queens to pesticide residues when hibernating in agricultural soils

Exposure to pesticides is a major threat to bumblebee (Bombus spp.) health. In temperate regions, queens of many bumblebee species hibernate underground for several months, putting them at potentially high risk of exposure to soil contaminants. The extent to which bumblebees are exposed to residues in agricultural soils during hibernation is currently unknown, which limits our understanding of the full pesticide exposome for bumblebees throughout their lifecycle. To generate field exposure estimates for overwintering bumblebee queens to pesticide residues, we sampled soils from areas corresponding to suitable likely hibernation sites at six apple orchards and 13 diversified farms throughout Southern Ontario (Canada) in fall 2019-2020. Detectable levels of pesticides were found in 65 of 66 soil samples analysed for multi-pesticide residues (UPLC-MS/MS). A total of 53 active ingredients (AIs) were detected in soils, including 27 fungicides, 13 insecticides, and 13 herbicides. Overall, the frequency of detection, residue levels (median = 37.82 vs. 2.20 ng/g), and number of pesticides per sample (mean = 12 vs. 4 AIs) were highest for orchard soils compared to soils from diversified farms. Ninety-one percent of samples contained multiple residues (up to 29 different AIs per sample), including mixtures of insecticides and fungicides that might lead to synergistic effects. Our results suggest that when hibernating in agricultural areas, bumblebee queens are very likely to be exposed to a wide range of pesticide residues in soil, including potentially harmful levels of insecticides (e.g., cyantraniliprole up to 148.82 ng/g). Our study indicates the importance of empirically testing the potential effects of pesticide residues in soils for hibernating bumblebee queens, using field exposure data such as those generated here. The differences in potential exposure that we detected between cropping systems can also be used to better inform regulations that govern the use of agricultural pesticides, notably in apple orchards.

Assessing spatial deposition of aquatic subsidies by insects emerging from agricultural streams

The role of winged aquatic insects that emerge from streams and subsidize terrestrial ecosystems has been demonstrated for natural forest landscapes, but almost no information is available for intensive agricultural landscapes. This study is the first to estimate aquatic subsidies provided by flying insects that emerge from streams and land on cropland. We investigated three major groups of aquatic insects - Trichoptera, Ephemeroptera and Chironomidae (Diptera) - that emerged from 12 third-order temperate, agricultural streams. We simultaneously monitored their emergence using floating traps and their terrestrial dispersal using passive interception traps. We estimated that the annual aquatic emerging dry mass (DM) of these groups varied from 1.4-7.5 g m^-2 yr^-1, depending on the stream. We used a Bayesian approach to estimate parameters of the terrestrial dispersal function of each group. We combined emerging DM and the dispersal parameters to estimate how terrestrial deposition of aquatic insect DM varied with increasing distance from streams. The results highlighted that emerging DM and dispersal to land could be higher in intensive agricultural landscapes than that previously described in natural settings. We estimated that 12.5 kg ha^-1 yr^-1 of winged aquatic insect DM fell to the ground 0-10 m from stream edges, composed mainly of Ephemeroptera and Trichoptera. We also estimated that 2.2 kg DM ha^-1 yr^-1 fell 10-50 m from the stream, especially small-bodied species of Chironomidae, throughout the year, except for the coldest weeks of winter. By influencing aquatic insect communities that emerge from streams, intensive agricultural practices change the magnitude and spatial extent of aquatic subsidy deposition on land. Implications for terrestrial food webs and ecosystem services provided to agriculture are discussed.

Bioaccumulation of pesticides and genotoxicity in anurans from southern Brazil

The expansion of agricultural activities causes habitat loss and fragmentation and the pollution of natural ecosystems through the intense use of pesticides, which may affect the populations of amphibian anurans that inhabit agricultural areas. The present study evaluated the in situ bioaccumulation of pesticides in a population of Leptodactylus luctator that occupies farmland in southern Brazil. We also compared the genotoxicity of L. luctator populations from farmland and forested areas in the same region. We analyzed the micronuclei and nuclear abnormalities of 34 adult anurans, 19 from farmland, and 15 from the forested area. We also assessed the presence of 32 pesticides in liver samples obtained from 18 farmland-dwelling anurans, using chromatographic analysis. We recorded significantly higher rates of nuclear abnormalities in the individuals from the farmland, in comparison with the forest. We detected nine pesticides in the liver samples, of which, deltamethrin was the most common and carbosulfan was recorded at the highest concentrations. The bioaccumulation of pesticides and the higher levels of genotoxic damage found in the anurans from agricultural areas, as observed in the present study, represent a major potential problem for the conservation of these vertebrates, including the decline of their populations and the extinction of species.

The biodiversity effect of reduced tillage on soil microbiota

The conversion of natural habitats into farmland has been a leading cause of species loss worldwide. Here, we investigated to what extent less intensive soil disturbance can mitigate this loss. Specifically, we examined whether reduced soil disturbance by tillage in agricultural fields could contribute to soil microbial biodiversity by providing a habitat for species that are limited by conventional tillage. To do so, we studied the diversity of soil biotas from three agricultural practices representing conventional tillage, reduced tillage and no tillage. Study fields were sampled by taking a bulk soil sample at the centre and edge of each field. The soil communities were recorded with environmental DNA metabarcoding using three molecular markers targeting bacteria, fungi and eukaryotes. While these three markers represent the vast majority of biotic variation in the soil, they will inevitably be dominated by the megadiverse microbiota of bacteria, microfungi and protists. We found a significant differentiation in community composition related to the intensity of tillage. Richness was weakly correlated to tillage, and more influenced by whether the sample was taken in the center or the edge of the field. Despite the significant effect of tillage on composition, comparisons with natural ecosystems revealed that all 30 study fields were much more similar in composition to other rotational fields than to more natural habitats, oldfields and leys. Despite a slightly higher similarity to oldfields and semi-natural grasslands, the contribution of no-till soil communities to biodiversity conservation is negligible, and our results indicate that restoration on set aside land may contribute more to conservation.

Fate of microplastics in agricultural soils amended with sewage sludge: Is surface water runoff a relevant environmental pathway?

Sewage sludge used as agricultural fertilizer has been identified as an important source of microplastics (MPs) to the environment. However, the fate of MPs added to agricultural soils is largely unknown. This study investigated the fate of MPs in agricultural soils amended with sewage sludge and the role of surface water runoff as a mechanism driving their transfer to aquatic ecosystems. This was assessed using three experimental plots located in a semi-arid area of Central Spain, which were planted with barley. The experimental plots received the following treatments: (1) control or no sludge application; (2) historical sludge application, five years prior to the experiment; and (3) sludge application at the beginning of the experiment. MPs were analyzed in surface water runoff and in different soil layers to investigate transport and infiltration for one year. The sewage sludge used in our experiment contained 5972-7771 MPs/kg dw. Based on this, we estimated that about 16,000 MPs were added to the agricultural plot amended with sludge. As expected, the sludge application significantly increased the MP concentration in soils. The control plot contained low MP concentrations (31-120 MPs kg^-1 dw), potentially originating from atmospheric deposition. The plot treated five years prior to the experiment contained 226-412 and 177-235 MPs kg^-1 dw at the start and end of the experiment, respectively; while the recently treated plot contained 182-231 and 138-288 MPs kg^-1 dw. Our study shows that MP concentrations remain relatively constant in agricultural soils and that the MP infiltration capacity is very low. Surface water runoff had a negligible influence on the export of MPs from agricultural soils, mobilizing only 0.2-0.4% of the MPs added with sludge. We conclude that, in semi-arid regions, agricultural soils can be considered as long-term accumulators of MPs.

Development of a new model for health assessment in agroecosystems

Healthy agroecosystems provide a range of ecosystem services, and the lack of information about the importance of their health degree leads to the unsustainability of these agroecosystems. To assess the health status of agroecosystems, a model was developed using spatial analysis-based procedures in Geographic Information System (GIS) media, surveyed data, and field monitoring at Gorgan University of Agricultural Sciences and Natural Resources. Initially, a survey-based study was conducted in 50 barley fields of Bandar-e-Torkaman County, north of Iran, during the 2016-2017 years. Then, the health index maps were provided by spatial analysis-based functions in GIS media. For accurate estimation of health status in barley agroecosystems, some meteorological variables were layered. Finally, the health status of the agroecosystems was determined based on six indices, including pesticides consumption rate, chemical fertilizers consumption rate, crop yield, and cultivar type, soil organic matter, and biodiversity indices. When all the layers overlaid, only 12% of the surveyed agroecosystems were located in the healthy class. The use of proper tillage methods, the appropriate weed control operations, the optimum consumption of high-quality pesticides, high soil organic matter, and grain yield > 2.6 ton ha^-1 were the main reasons for obtaining of health degree in these agroecosystems. In contrast, the consumption of low-quality pesticides, the use of inappropriate tillage tools and machinery, the little knowledge of the farmers about the optimum rates and consumption methods of pesticides and chemical fertilizers, and resistance of some weeds to herbicides were identified as the most essential reasons for non-health status in the most surveyed barley agroecosystems.

Soil carbon stock and stability under Eucalyptus-based silvopasture and other land-use systems in the Cerrado biodiversity hotspot

During the past few decades, commercial silvopastoral systems (SPS) with exotic Eucalyptus (hybrid) trees have become popular in the Brazilian Cerrado (savanna). With the increasing awareness about the role of carbon (C) storage in soils as a climate-change mitigation strategy and the relationship between the nature of soil aggregates and the soil's carbon sequestration potential, it is important to understand the influence of such SPS systems on soil organic carbon (SOC) storage. We studied C content in three aggregate size classes in six land-use systems on Oxisols in Minas Gerais, Brazil. The systems were planted forest, native secondary forest, managed pasture, and three 8-year-old SPS, differing in their tree-planting configurations. Eucalyptus hybrid was the tree in SPS and planted forest treatments, and Urochloa decumbens was the grass in SPS and pasture treatments. From each treatment, replicated soil samples were collected from four depth-classes (0-10, 10-30, 30-60, and 60-100 cm), fractionated by wet sieving into the three aggregate-size classes, 2000 to 250 μm, 250 to 53 μm, and <53 μm size classes representing macroaggregates, microaggregates, and silt + clay, respectively, and their C contents determined. Down to 1 m, total SOC stock values ranged from 260 Mg ha^-1 under pasture to 167 Mg ha^-1 under native forest, with 174 Mg ha^-1 for Eucalyptus plantation and about 195 Mg ha^-1 for the three SPS. Compared to the degraded native forest, the pasture system had significantly higher SOC in the whole soil and the aggregate size fractions, especially in the lower soil-depth classes. The lower SOC stock of Eucalyptus hybrid SPS compared to open pasture differs from the general trend of SPS having higher stock. Given that the Cerrado biome is a biodiversity hotspot, the use of native nitrogen-fixing trees, of which there are several, is worth investigating. In addition, the conversion from Eucalyptus monocultures to SPS could be considered as a strategy to increase the SOC stock.

Arable fields as potential reservoirs of biodiversity: Earthworm populations increase in new leys

Managing soil to support biodiversity is important to sustain the ecosystem services provided by soils upon which society depends. There is increasing evidence that functional diversity of soil biota is important for ecosystem services, and has been degraded by intensive agriculture. Importantly, the spatial distribution of reservoirs of soil biota in and surrounding arable fields is poorly understood. In a field experiment, grass-clover ley strips were introduced into four arable fields which had been under continuous intensive/conventional arable rotation for more than 10 years. Earthworm communities in arable fields and newly established grass-clover leys, as well as field boundary land uses (hedgerows and grassy field margins), were monitored over 2 years after arable-to-ley conversions. Within 2 years, earthworm abundance in new leys was 732 ± 244 earthworms m^-2, similar to that in field margin soils (619 ± 355 earthworms m^-2 yr^-1) and four times higher than in adjacent arable soil (185 ± 132 earthworms m^-2). Relative to the arable soils, earthworm abundance under the new leys showed changes in community composition, structure and functional group, which were particularly associated with an increase in anecic earthworms; thus new leys became more similar to grassy field margins. Earthworm abundance was similar in new leys that were either connected to biodiversity reservoirs i.e. field margins and hedgerows, or not (installed earthworm barriers). This suggests that, for earthworm communities in typical arable fields, biodiversity reservoirs in adjacent field margins and hedgerows may not be critical for earthworm populations to increase. We conclude that the increase in earthworm abundance in the new leys observed over 2 years was driven by recruitment from the existing residual population in arable soils. Therefore, arable soils are also potential reservoirs of biodiversity.

Next-Generation Sequencing and Its Impacts on Entomological Research in Ecology and Evolution

The advent of NGS-based methods has been profoundly transforming entomological research. Through continual development and improvement of different methods and sequencing platforms, NGS has promoted mass elucidation of partial or whole genetic materials associated with beneficial insects, pests (of agriculture, forestry and animal, and human health), and species of conservation concern, helping to unravel ecological and evolutionary mechanisms and characterizing survival, trophic interactions, and dispersal. It is shifting the scale of biodiversity and environmental analyses from individuals and biodiversity indicator species to the large-scale study of communities and ecosystems using bulk samples of species or a mixed "soup" of environmental DNA. As the NGS-based methods have become more affordable, complexity demystified, and specificity and sensitivity proven, their use in entomological research has spread widely. This article presents several examples on how NGS-based methods have been used in entomology to provide incentives to apply them when appropriate and to open our minds to the expected advances in entomology that are yet to come.

Can stable isotopes quantify soil carbon build-up from organic fertilizers?

The application of organic fertilizers (OF) can supply carbon (C) to the soil in crop fields. OF-derived C (OF-C) is often estimated using the differential method that can be biased due to indirect effects of OF on soil C. This study tested three methods to quantify OF-C: (i) the widespread differential method, (ii) the synchronic isotope method comparing plots with and without OF and (iii) the asynchronic isotope method mimicking a trial without a control plot. These methods were implemented on an Arenosol and an Andosol supplied during 13 years with slurry or compost. The results highlighted the relevance of using the synchronic isotope method, which focuses on the direct effect of OFs on the soil organic matter (without bias of vegetation change) and considers control soil's evolution. The higher the isotopic difference between soil and OF, the shorter the method implementation time needed: for an initial difference of 7.5 ‰ and 3.5 ‰, quantification is suitable after 4 and 9 years of fertilization respectively. Attention should be paid to OF-δ¹³C variability to guarantee the method validity. The method proved to be suitable to study the factors controlling the OF-C fate in tropical soils.

Geochemical fingerprint of agricultural liming as a regular management practice in Modern-period Basque farming

The Modern period in Europe is marked by the introduction of deep agricultural changes. In the Basque Country (northern Spain), the implantation of an intensive crop rotation was made possible by the expansion of agricultural liming, although the extent and implications of this practice have not been previously explored in depth. The present paper proposes a multidisciplinary approach to this question, based on the combined analysis of archival sources, toponymy, visual prospection focused on the presence of limekilns, and agricultural soil coring in four local contexts of the Atlantic Basque Country. The results show, for the first time, evidence of concurrent and widespread liming in this territory at the edge of the 18th century, with strong implications for the model of agricultural management in the communities involved. The spreading of mineral fertilisation reflects an intensification in the forms of agricultural management, in the framework of a new relationship between land and labour that emerged after the introduction of American crops. Continuous liming for more than 200 years exerted a deep impact in the analysed soils, with interesting socio-economic and ecological implications that are representative of the potential short-term effects that changing relationship between humans and their socio-ecological environment may produce in agricultural soils.

Impacts of neonicotinoid seed treatments on the wild bee community in agricultural field margins

Wild bees support global agroecosystems via pollination of agricultural crops and maintaining diverse plant communities. However, with an increased reliance on pesticides to enhance crop production, wild bee communities may inadvertently be affected through exposure to chemical residues. Laboratory and semi-field studies have demonstrated lethal and sublethal effects of neonicotinoids on limited genera (e.g., Apis, Bombus, Megachile), yet full field studies evaluating impacts to wild bee communities remain limited. Here, we conducted a two-year field study to assess whether neonicotinoid seed treatment and presence in environmental media (e.g., soil, flowers) influenced bee nest and diet guild abundance and richness. In 2017 and 2018, we planted 23 Missouri agricultural fields to soybeans (Glycine max) using one of three seed treatments: untreated (no insecticide), treated (imidacloprid), or previously-treated (untreated, but neonicotinoid use prior to 2017). During both years, wild bees were collected in study field margins monthly (May to September) in tandem with soil and flowers from fields and field margins that were analyzed for neonicotinoid residues. Insecticide presence in soils and flowers varied over the study with neonicotinoids infrequently detected in both years within margin flowers (0%), soybean flowers (<1%), margin soils (<8%), and field soils (~39%). Wild bee abundance and species richness were not significantly different among field treatments. In contrast, neonicotinoid presence in field soils was associated with significantly lower richness (ground- and aboveground-nesting, diet generalists) of wild bee guilds. Our findings support that soil remains an underexplored route of exposure and long-term persistence of neonicotinoids in field soils may lead to reduced diversity in regional bee communities. Future reduction or elimination of neonicotinoid seed treatment use on areas managed for wildlife may facilitate conservation goals to sustain viable, diverse wild bee populations.

Conservation risks and benefits of establishing monarch butterfly (Danaus plexippus) breeding habitats close to maize and soybean fields in the north central United States: A landscape-scale analysis of the impact of foliar insecticide on nonmigratory monarch butterfly populations

Establishing habitat in agricultural landscapes of the north central United States is critical to reversing the decline of North America's eastern monarch butterfly (Danaus plexippus) population. Insecticide use could create population sinks and threaten recovery. Discouraging habitat establishment within a 38-m zone around crop fields is a suggested risk mitigation measure. In Story County, Iowa, United States, this mitigation would discourage habitat establishment in 84% of roadsides and 38% of noncrop land. It is unclear if the conservation benefits from establishing habitat close to crop fields outweigh suppression of population growth owing to insecticide exposure. Consequently, monarch conservation plans require spatially and temporally explicit landscape-scale assessments. Using an agent-based model that incorporates female monarch movement and egg laying, the number and location of eggs laid in Story County were simulated for four habitat scenarios: current condition, maximum new establishment, moderate establishment, and moderate establishment only outside a 38-m no-plant zone around crop fields. A demographic model incorporated mortality from natural causes and insecticide exposure to simulate adult monarch production over 10 years. Assuming no insecticide exposure, simulated adult production increased 24.7% and 9.3%, respectively, with maximum and moderate habitat establishment and no planting restrictions. A 3.5% increase was simulated assuming moderate habitat establishment with a 38-m planting restriction. Impacts on adult production were simulated for six representative insecticides registered for soybean aphid (Aphis glycines) management. Depending on the frequency of insecticide applications over a 10-year period, simulated production increased 8.2%-9.3%, assuming moderate habitat establishment with no planting restrictions. Results suggest that the benefits of establishing habitat close to crop fields outweigh the adverse effects of insecticide spray drift; that is, metapopulation extirpation is not a concern for monarchs. These findings are only applicable to species that move at spatial scales greater than the scale of potential spray-drift impacts. Integr Environ Assess Manag 2021;17:989-1002. © 2021 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

A Review on Biosensors and Nanosensors Application in Agroecosystems

Previous decades have witnessed a lot of challenges that have provoked a dire need of ensuring global food security. The process of augmenting food production has made the agricultural ecosystems to face a lot of challenges like the persistence of residual particles of different pesticides, accretion of heavy metals, and contamination with toxic elemental particles which have negatively influenced the agricultural environment. The entry of such toxic elements into the human body via agricultural products engenders numerous health effects such as nerve and bone marrow disorders, metabolic disorders, infertility, disruption of biological functions at the cellular level, and respiratory and immunological diseases. The exigency for monitoring the agroecosystems can be appreciated by contemplating the reported 220,000 annual deaths due to toxic effects of residual pesticidal particles. The present practices employed for monitoring agroecosystems rely on techniques like gas chromatography, high-performance liquid chromatography, mass spectroscopy, etc. which have multiple constraints, being expensive, tedious with cumbersome protocol, demanding sophisticated appliances along with skilled personnel. The past couple of decades have witnessed a great expansion of the science of nanotechnology and this development has largely facilitated the development of modest, quick, and economically viable bio and nanosensors for detecting different entities contaminating the natural agroecosystems with an advantage of being innocuous to human health. The growth of nanotechnology has offered rapid development of bio and nanosensors for the detection of several composites which range from several metal ions, proteins, pesticides, to the detection of complete microorganisms. Therefore, the present review focuses on different bio and nanosensors employed for monitoring agricultural ecosystems and also trying to highlight the factor affecting their implementation from proof-of-concept to the commercialization stage.

SDM-CropProj - A model-assisted framework to forecast crop environmental suitability and fruit production

The effects of climate change (CC) will impact species ranges, and crops are no exception. Anticipating these changes through forecasting the environmentally suitable area of crops would help to reduce or mitigate the impact and adapt ecological and economic strategies. To forecast the CC effects on crops, we describe here a model-assisted framework (hereafter SDM-CropProj) that combines two modelling steps to be implemented in sequence: i) a multi-technique calibration process and ensemble-forecasting approach to predict the current and future environmental suitability of target crops; ii) a parsimonious univariate log-log linear model to relate the average total annual production to the current SDM-based suitable area. Different metrics for assessing the model's predictive performance showed that:•

Crop production is related to model-predicted suitable area, thus allowing to obtain future projections of total fruit production based on climate scenarios.

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The SDM-CropProj framework can assess potential pathways and trends in annual production due to changes in the environmental suitability and the distribution of multiple crop varieties/types as a consequence of CC, offering insights to other areas and crop types.

The methodological strategies of agroecological research and the values with which they are linked

The characteristic features of some of the methodological strategies adopted in scientific research in agroecology are discussed. They reflect that agroecology, as an approach to scientific research, is inextricably entangled with the other strands of agroecology (farming practice, social movement, political project); and that adopting agroecological strategies, and upholding the values of environmental sustainability, food sovereignty, social justice and democratic participation, mutually reinforce each other. After outlining the kinds of questions that agroecological research addresses so that it can produce knowledge that informs agroecological farming practices and the long term aspiration of agroecological movements to create an alternative agricultural/food system, and then making summary remarks about methodological strategies in general, three characteristic features of some agroecological strategies are introduced and discussed. The paper concludes with comments on the value of agroecological research.

Could more efficient utilization of ecosystem services improve soil quality indicators to allow sustainable intensification of Amazonian family farming?

In the Amazonian periphery, there are sources of numerous disservices, including deforestation, loss of wildlife habitat and biodiversity erosion. However, there are great opportunities to adopt appropriate agricultural management practices to take advantage of the benefits of ecosystem services for sustainable agricultural intensification. Thus, the aim of this work was to evaluate the effects of certain ecosystem services provided by combined use of legumes with residue of low- and high-quality on soil quality indicators, nitrogen use efficiency and sustainability of maize grain yield in infertile tropical soil. The overarching objective is to determine how ecosystem services can contribute to the improvement of land-use policy to ensure the sustainability of cultivated lands, in such a way that forest can be preserved by avoiding deforestation of other new areas through shifting cultivation systems. Four leguminous tree species were used, two with high-quality residues Leucaena leucocephala (leucaena) and Gliricidia sepium (gliricidia) and two with low-quality residues Clitoria fairchildiana (clitoria) and Acacia mangium (acacia). Maize grain yield was evaluated between 2011 and 2017 in these treatments. In 2018, to assess how ecosystem services affect crop performance, the treatments were divided into ten treatments with and without urea. We conclude that increased uptake of inorganic and organic N by maize resulting from improvement of the soil quality indicators may allow agricultural intensification. This improvement can help meet the challenges of sustainability and feasibility of agroecosystems of the Amazonian periphery by making the agroecosystem more productive year by year. Therefore, our results confirm that the utilization of an ecosystem services style approach can help meet the challenges of sustainability and feasibility in agrosystems of the Amazonian periphery. In addition, these results can contribute to the development of land-use policy in the Amazonian periphery, aiming for the intensification of agriculture in cropped areas to avoid deforestation of new areas from shifting cultivation systems.

Sorption and dissipation of the allelochemicals umbelliferone and salicylic acid in a Mediterranean soil environment: Effect of olive-mill waste addition

Allelochemicals are receiving much attention as natural alternatives to synthetic pesticides. Very little is known, however, about the processes to which allelochemicals are subjected once they reach the soil environment, despite the fact that it is widely recognized that such processes can dramatically influence their bioactivity and applicability as eco-friendly pesticides. The objectives of this study were to characterize the sorption and dissipation of two phenolic allelochemicals, umbelliferone (UM) and salicylic acid (SA), after their simultaneous application to a Mediterranean agricultural soil and to assess to what extent sorption and dissipation were affected by amending the soil with an agro-industrial organic waste (olive-mill waste, OMW), as a common agronomic practice in Mediterranean agricultural systems. In experiments conducted under standard laboratory conditions, UM (pK_a = 7.5) showed greater sorption than SA (pK_a = 2.8) and both allelochemicals displayed very short half-lives in the tested soil (DT₅₀ < 1 day). Furthermore, the addition of OMW increased the sorption of UM and the half-lives of both SA and UM in the soil. A field experiment conducted on unamended and OMW-amended soil plots confirmed the ability of OMW to increase the persistence of SA and UM under a real Mediterranean soil environment and showed that, for all treatments, the allelochemicals displayed higher half-lives in the field than under standard laboratory conditions. This was attributed to reduced biodegradation of UM and SA under progressive soil drying, which was thus identified as a factor that can prolong the persistence of allelochemicals in semi-arid soil environments. We highlight the need to test the environmental fate of allelochemicals under specific agro-climatic scenarios and illustrate how management practices can help increase their soil persistence so that their bioactivity can be better expressed.

Monarch Butterfly (Danaus plexippus) Life-Stage Risks from Foliar and Seed-Treatment Insecticides

Conservation of North America's eastern monarch butterfly (Danaus plexippus) population would require establishment of milkweed (Asclepias spp.) and nectar plants in the agricultural landscapes of the north central United States. A variety of seed-treatment and foliar insecticides are used to manage early- and late-season pests in these landscapes. Thus, there is a need to assess risks of these insecticides to monarch butterfly life stages to inform habitat conservation practices. Chronic and acute dietary toxicity studies were undertaken with larvae and adults, and acute topical bioassays were conducted with eggs, pupae, and adults using 6 representative insecticides: beta-cyfluthrin (pyrethroid), chlorantraniliprole (anthranilic diamide), chlorpyrifos (organophosphate), imidacloprid, clothianidin, and thiamethoxam (neonicotinoids). Chronic dietary median lethal concentration values for monarch larvae ranged from 1.6 × 10^-3 (chlorantraniliprole) to 5.3 (chlorpyrifos) μg/g milkweed leaf, with the neonicotinoids producing high rates of arrested pupal ecdysis. Chlorantraniliprole and beta-cyfluthrin were generally the most toxic insecticides to all life stages, and thiamethoxam and chlorpyrifos were generally the least toxic. The toxicity results were compared to insecticide exposure estimates derived from a spray drift model and/or milkweed residue data reported in the literature. Aerial applications of foliar insecticides are expected to cause high downwind mortality in larvae and eggs, with lower mortality predicted for adults and pupae. Neonicotinoid seed treatments are expected to cause little to no downslope mortality and/or sublethal effects in larvae and adults. Given the vagile behavior of nonmigratory monarchs, considering these results within a landscape-scale context suggests that adult recruitment will not be negatively impacted if new habitat is established in close proximity of maize and soybean fields in the agricultural landscapes of the north central United States. Environ Toxicol Chem 2021;40:1761-1777. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Steering the restoration of degraded agroecosystems during the United Nations Decade on Ecosystem Restoration

Agroecosystems are the largest human-natural coupled production system covering ~40% of the planet earth and provide essential ecosystem services for a good quality of life and human wellbeing. The sustainable management of agroecosystems are therefore essential for meeting the food, fuel, fiber, and fodder demands of the rapidly growing human population. Agroecosystems also play a key role in trace gases emission, and also affect the quality and usage of life-supporting resources such as air, water, soil etc. Though the sustainable management of agroecosystems are imperative for achieving UN-Sustainable Development Goals, they are frequently under degradation due to multiple drivers of changes such as unsustainable land-use practices, biodiversity loss, pollution and climate change, etc. Therefore, cordial efforts at national, regional and global levels are essential for managing agroecosystems to meet out the global goals and also the targets of the United Nations- Decade o-n Ecosystem Restoration (2021-2030). Here we opined various strategies for restoring degraded agroecosystems for sustainable development including the adoption of emerging paradigms such as micro-agriculture, urban agriculture, and landless agriculture for averting the mounting pressure on agroecosystems for the benefit of both people and the planet.

Effects of mixing two legume species at seedling stage under different environmental conditions

While intercropping is known to have positive effects on crop productivity, it is unclear whether the effects of mixing species start at the early plant stage, that is, during germination. We tested whether the germination of two legume species, alsike clover and black medic, characterized by a contrasting response to water availability and temperature is affected by mixing. We set up four experiments in each of which we compared a 1:1 mixture against the two monocultures, and combined this with various other experimental factors. These additional factors were (i) varied seed densities (50%, 100% and 150% of a reference density) in two field trials in 2016 and 2017, (ii) varied seed densities (high and low) and water availability (six levels, between 25% and 100% of water holding capacity (WHC)) in a greenhouse pot trial, (iii) varied seed spacing in a climate chamber, and (iv) varied temperatures (12 °C, 20 °C and 28 °C) and water availability (four levels between 25% and 100% of WHC) in a climate chamber. Across all experiments, the absolute mixture effects (AME) on germination ranged between −9% and +11%, with a median of +1.3%. Within experiments, significant mixture effects were observed, but the direction of these effects was inconsistent. In the field, AME on germination was significantly negative at some of the tested seed densities. A positive AME was observed in the climate chamber at 12 °C, and the mean AME decreased with increasing temperature. Higher density was associated with decreased germination in the field, indicating negative interaction through competition or allelopathy, among seedlings. Our findings indicate that interaction among seeds in species mixtures may be ongoing during germination, but that the direction of the mixture effect is affected by complex interactions with abiotic and biotic factors.

Environmental salinization processes: Detection, implications & solutions

A great portion of Earth's freshwater and land resources are salt-affected and thus have restricted use or may become unsuitable for most human activities. Some of the recent scenarios warn that environmental salinization processes will continue to be exacerbated due to global climate change. The most relevant implications and side-effects in ecosystems under excessive salinity are destructive and long lasting (e.g. soil dispersion, water/soil hypersalinity, desertification, ruined biodiversity), often with non-feasible on site remediation, especially at larger scales. Agro-ecosystems are very sensitive to salinization; after a certain threshold is reached, yields and food quality start to deteriorate sharply. Additionally, salinity often coincides with numerous other environmental constrains (drought, waterlogging, pollution, acidity, nutrient deficiency, etc.) that progressively aggravate the threat to food security and general ecosystem resilience. Some well-proven, widely-used and cost-effective traditional ameliorative strategies (e.g. conservation agriculture, application of natural conditioners) help against salinity and other constraints, especially in developing countries. Remotely-sensed and integrated data of salt-affected areas combined with in situ and lab-based observations have never been so easy and rapid to acquire, precise and applicable on huge scales, representing a valuable tool for policy-makers and other stakeholders in implementing targeted measures to control and prevent ecosystem degradation (top-to-bottom approach). Continued progress in biotechnology and ecoengineering offers some of the most advanced and effective solutions against salinity (e.g. nanomaterials, marker-assisted breeding, genome editing, plant-microbial associations), albeit many knowledge gaps and ethical frontiers remain to be overcome before a successful transfer of these potential solutions to the industrial-scale food production can be effective.

Unraveling consequences of soil micro- and nano-plastic pollution on soil-plant system: Implications for nitrogen (N) cycling and soil microbial activity

Micro- and nano-plastics have widely been recognized as major global environmental problem due to its widespread use and inadequate waste management. The emergence of these plastic pollutants in agroecosystem is a legitimate ecotoxicological concerns for food web exchanges. In agriculture, micro/nano plastics are originated from a variety of different agricultural management practices, such as the use of compost, sewage sludge and mulching. A range of soil properties and plant traits are affected by their presence. With the increase of plastic debris, these pollutant materials have now begun to demonstrate serious implications for key soil ecosystem functions, such as soil microbial activity and nutrient cycling. Nitrogen (N) cycle is key predictor of ecological stability and management in terrestrial ecosystem. In this review, we evaluate ecological risks associated with micro-nano plastic for soil-plant system. We also discuss the consequence of plastic pollutants, either positive or negative, on soil microbial activities. In addition, we systematically summarize both direct and hypothesized implications for N cycling in agroecosystem. We conclude that soil N transformation had showed varied effects resulting from different types and sizes of plastic polymers present in soil. While mixed effects of microplastic pollution on plant growth and yield have been observed, biodegradable plastics have appeared to pose greater risk for plant growth compared to chemical plastic polymers.

A two years field experiment to assess the impact of two fungicides on earthworm communities and their recovery

Recent EFSA (European Food Safety Authority) reports highlighted that the ecological risk assessment of pesticides needed to go further by taking more into account the impacts of chemicals on biodiversity under field conditions. We assessed the effects of two commercial formulations of fungicides separately and in mixture, i.e., Cuprafor Micro® (containing 500 g kg^-1 copper oxychloride) at 4 (C1, corresponding to 3.1 mg kg^-1 dry soil of copper) and 40 kg ha^-1 (C10), and Swing® Gold (50 g L^-1 epoxiconazole EPX and 133 g L^-1 dimoxystrobin DMX) at one (D1, 5.81 10^-2 and 1.55 10^-1 mg kg^-1 dry soil of EPX and DMX, respectively) and ten times (D10) the recommended field rate, on earthworms at 1, 6, 12, 18 and 24 months after the application following the international ISO standard no. 11268-3 to determine the effects on earthworms in field situations. The D10 treatment significantly reduced the species diversity (Shannon diversity index, 54% of the control), anecic abundance (29% of the control), and total biomass (49% of the control) over the first 18 months of experiment. The Shannon diversity index also decreased in the mixture treatment (both fungicides at the recommended dose) at 1 and 6 months after the first application (68% of the control at both sampling dates), and in C10 (78% of the control) at 18 months compared with the control. Lumbricus terrestris, Aporrectodea caliginosa, Aporrectodea giardi, Aporrectodea longa, and Allolobophora chlorotica were (in decreasing order) the most sensitive species to the tested fungicides. This study not only addressed field ecotoxicological effects of fungicides at the community level and ecological recovery, but it also pinpointed some methodological weaknesses (e.g., regarding fungicide concentrations in soil and statistics) of the guideline to determine the effects on earthworms in field situations.

Marine macroalgae as food for earthworms: growth and selection experiments across ecotypes

Historically, subsistence farmers around the Atlantic coast of NW Europe utilized marine algae as a fertilizer in agroecosystems, a practice that continued in small areas and is now considered to have real potential for re-establishing sustainable food production systems on marginal soils. Earthworms form a significant component of soil fauna, and their ecosystem services are well-documented. Therefore, palatability of marine organic amendments to faunal detritivores of terrestrial systems is of interest. This work aimed to assess the potential for growth of Aporrectodea caliginosa, Lumbricus rubellus and Aporrectodea longa fed with two common macroalgae (seaweeds), Laminaria digitata and Fucus serratus. In addition, choice chambers were constructed to permit earthworm selection of these macroalgae with more conventional organic materials, horse manure (HM) and birch leaves (BL). Over a period of 2 months, earthworm species showed significantly greater mass gain with conventional food (p < 0.05). Laminaria outperformed Fucus, which in turn was superior to soil alone. Similarly, when given a choice, a significant preference (p < 0.001) was shown for the more nitrogen-rich HM and BL over the seaweeds. No removal was recorded for A. caliginosa when offered seaweeds only. By contrast, L. rubellus and A. longa showed significant preferences (p < 0.001) for Laminaria over Fucus and fresh material over degraded. These results underline an interest to profit from natural resources (seaweeds) to maintain or improve soil biological quality in marginal coastal areas.

Population genetics and diversity structure of an invasive earthworm in tropical and temperate pastures from Veracruz, Mexico

Pontoscolexcorethrurus (Müller, 1857) is an invasive tropical earthworm, globally distributed. It reproduces through parthenogenesis, which theoretically results in low genetic diversity. The analysis of the population structure of P.corethrurus using molecular markers may significantly contribute to understanding the ecology and reproductive system of this earthworm species. This work assessed the genetic diversity and population structure of P.corethrurus with 34 polymorphic inter simple sequence repeat markers, covering four populations in tropical and temperate pastures from Veracruz State. Nuclear markers distinguished two genetic clusters, probably corresponding to two distinct genetic lineages. The number of clones detected in the AC population was lower than expected for a parthenogenetic species. Also, the apparent lack of differences in population structures related to the geographic region among the populations studied may indicate that human-mediated transference is prevalent in these areas. Still, most individuals apparently belong to lineage A, and only a few individuals seem to belong to the lineage B. Thus, the admixture signatures found among the four populations of P.corethrurus may have facilitated a successful invasion by directly increasing fitness. In summary, addressing the genetic variation of P.corethrurus with ISSR markers was a suitable approach, as it evidenced the genetic diversity and relationships in the populations evaluated.

A review of the effectiveness of vegetated buffers to mitigate pesticide and nutrient transport into surface waters from agricultural areas

A relatively large number of studies have investigated the effectiveness of vegetated buffer strips at reducing the movement of pesticides and nutrients from agriculture fields. This review outlines the observed influence of different factors (e.g., buffer width, slope, runoff intensity, soil composition, plant community) that can influence the efficacy of vegetated buffers in pesticide and nutrient retention. The reported effectiveness of vegetated buffers reducing the movement of pesticides and nutrients ranged from 10 to 100% and 12-100%, respectively. Buffer width is the factor that is most frequently considered by various jurisdictions when making recommendations on vegetated buffer strip implementation. However, the literature clearly illustrates that there is a great deal of variation in pesticide or nutrient reduction for a given buffer width. This indicates that other factors play an important role in buffer efficacy (e.g., ratio of source area to buffer area, soil composition and structure, runoff intensity, plant community structure) in addition to the width of the vegetative buffer area. These factors need to be considered when making recommendations on vegetated buffer strip construction in agroecosystems. This review has also identified a number of other gaps in the understanding of the effectiveness of vegetated buffers at reducing the movement of pesticides and nutrients from the areas of application.

Enhancing healthy ecosystems in northern Ghana through eco-friendly farm-based practices: insights from irrigation scheme-types

Background

Farming practices vary from farmer to farmer and from place to place depending on a number of factors including the agroclimatic condition, infrastructure (e.g. irrigation facilities) and management mechanisms (private versus state management). These together affect the functioning and sustainability of the ecosystems. For the sustainability of ecosystems, farmers need to employ ecosystem-based farm practices. This paper examines the ecosystem-based farm management practices (EBFMPs) in private and state-managed irrigation schemes. It also analyses the drivers of farmers’ willingness to pay for EBFMPs sustainability. The study employed mixed methods design, using both qualitative and quantitative techniques of data collection through key informant interviews, focus group discussions and semi-structured questionnaires administered to 300 households. The various EBFMPs adopted by farmers were examined and descriptively presented. The Chi-square automatic interaction detector (CHAID) and multiple linear regression were used to assess the predictors of farmers’ willingness to pay for EBFMPs to enhance the health of agroecosystems. Compost application, conservative tilling, conservation of vegetation, mulching, crop rotation, intercropping with legumes, efficient drainage systems and bunding were the EBFMPs captured in this paper.

Results

Farmers in privately-managed irrigation schemes (PIS) more often apply EBFMPs compared with those in state-managed irrigation schemes (SIS). The paper also found that farmers’ willingness to pay to sustain EBFMPs for healthy ecosystems is significantly determined by the type of irrigation scheme they cultivate in (that is, PIS or SIS), their level of education, marital status and perception of soil fertility.

Conclusions

Policy makers, implementers, and other stakeholders need to consider the capacity building of irrigation farmers, especially those in SIS in northern Ghana by educating them on agricultural production and ecosystem nexus to enhance the level of usage and willingness to pay for EBFMPs sustainability.

One Health and Antibiotic Resistance in Agroecosystems

Agriculture reflects One Health principals, with the job of the farmer being to sustainably balance human, animal, and soil health. It is imperative to include an agricultural perspective when addressing antibiotic resistance (AR) from a One Health perspective, as the farmers, ranchers, and agricultural professionals have an intimate working knowledge of these complex systems, and they will be on the front lines of implementing on-farm control measures. Currently, communication across the One Health triad (humans, animals, environment) regarding agricultural AR is hindered by ambiguous language, complicated by cultural and linguistic differences that can lead to the conclusion that the other participant is not aware of the facts, or has ulterior motives. This work explores and identifies the language and vocabulary of AR in the context of supporting strategic short- and long-term problem solving in a One Health context.

The role of vegetated buffers in agriculture and their regulation across Canada and the United States

A vegetated buffer, barrier, or filter strip is a parcel of land that is designated to separate land used for agriculture from valued aquatic or terrestrial habitats. It exists partly with the intent to diffuse runoff and to impeded sediment, nutrients, pesticides, and other constituents from reaching off-site surface waters. Mandatory buffer implementation is regulated at various levels of government in North America - from the federal to the state and provincial levels, and by some municipalities and counties. To better understand the degree and breadth of oversight, we undertook a comprehensive search and review of vegetative buffer regulations across North America. We determined the width of buffer required, under what habitat or field conditions, for which pesticides, and application type, amongst other attributes. For ground application, margins ranged from 1 m to upwards of greater than 4000 m depending on protection goals, with some being compound specific and others being generally applied to all registered pesticides/compounds. These buffers tended to be used most often to protect surface water, groundwater (e.g. drinking water wells), and nearby sensitive crops, but the required distances are generally not consistent between jurisdictions, regardless of the stated protection goals. We recommend that a thorough science-based review take place, with input from relevant stakeholders, to harmonize vegetated buffer size for effective surface water protection where ecological, climatic, and agricultural conditions are sufficiently similar in North America.

Rare earth elements (REY) sorption on soils of contrasting mineralogy and texture

Rare earth elements (REY) are the lanthanide elements (Z = 57-71), which have an ever-growing occurrence in present-day industries, agriculture, and modern life. Consequently, environmental concentrations are expected to increase accordingly as a result of intensified utilization. Soils are an important sink for REY, yet little research has been conducted concerning activity, inputs, and lability in soil systems. This study evaluated the REY (lanthanides + yttrium) sorption and partition coefficients (K_d) in two broadly representative natural soils (A horizon), with contrasting mineralogy and organic character, formed under distinct environmental conditions: an Oxisol from Brazil and a Mollisol from the USA. Batch reactions of soils suspended in a background electrolyte solution of 5 μmoles kg^-1 of Ca(NO₃)₂ at 1:100 solid to solution were reacted with 80 μmoles kg^-1 REY added individually and in multi-REY competitive systems to evaluated adsorption after 3 h and 72 h over a wide pH range (from ca. 2 to 8). Results showed sorption was similar for all REY within each soil type when examined at the natural measured soil pH; Mollisol pH 6.85, Oxisol pH 4.35. However, REY sorption (by K_d) was nearly two-fold greater in the Mollisol compared to the Oxisol for the single REY experiments. Multi-REY competitive sorption reactions showed a decrease in K_d for both soils at 3 and 72 h, and to a greater extent for the Mollisol, indicating soil type had a strong effect on the sorption affinity of each REY. It was also observed that REY sorption increased from low to high pH (pH 2-8) in the Oxisol, and increased with pH from 2 up to the point zero charge (PZC) in the Mollisol, then stabilized. The varying REY K_d values from these two distinct and abundant soils, with and without REY competition, and over a range of pH are explained in terms of soil mineralogy (i.e., 2:1 clays in the Mollisol; oxides in the Oxisol) and organic matter content. Our findings show that soil characteristic controls sorption, precipitation, and cation exchange capacity, which are the key mechanisms for predicting REY fate and transport in the environment.