Long-term push-pull cropping system shifts soil and maize-root microbiome diversity paving way to resilient farming system.

BACKGROUND: The soil biota consists of a complex assembly of microbial communities and other organisms that vary significantly across farming systems, impacting soil health and plant productivity. Despite its importance, there has been limited exploration of how different cropping systems influence soil and plant root microbiomes. In this study, we investigated soil physicochemical properties, along with soil and maize-root microbiomes, in an agroecological cereal-legume companion cropping system known as push-pull technology (PPT). This system has been used in agriculture for over two decades for insect-pest management, soil health improvement, and weed control in sub-Saharan Africa. We compared the results with those obtained from maize-monoculture (Mono) cropping system. RESULTS: The PPT cropping system changed the composition and diversity of soil and maize-root microbial communities, and led to notable improvements in soil physicochemical characteristics compared to that of the Mono cropping system. Distinct bacterial and fungal genera played a crucial role in influencing the variation in microbial diversity within these cropping systems. The relative abundance of fungal genera Trichoderma, Mortierella, and Bionectria and bacterial genera Streptomyces, RB41, and Nitrospira were more enriched in PPT. These microbial communities are associated with essential ecosystem services such as plant protection, decomposition, carbon utilization, bioinsecticides production, nitrogen fixation, nematode suppression, phytohormone production, and bioremediation. Conversely, pathogenic associated bacterial genus including Bryobacter were more enriched in Mono-root. Additionally, the Mono system exhibited a high relative abundance of fungal genera such as Gibberella, Neocosmospora, and Aspergillus, which are linked to plant diseases and food contamination. Significant differences were observed in the relative abundance of the inferred metabiome functional protein pathways including syringate degradation, L-methionine biosynthesis I, and inosine 5'-phosphate degradation. CONCLUSION: Push-pull cropping system positively influences soil and maize-root microbiomes and enhances soil physicochemical properties. This highlights its potential for agricultural and environmental sustainability. These findings contribute to our understanding of the diverse ecosystem services offered by this cropping system where it is practiced regarding the system's resilience and functional redundancy. Future research should focus on whether PPT affects the soil and maize-root microbial communities through the release of plant metabolites from the intercrop root exudates or through the alteration of the soil's nutritional status, which affects microbial enzymatic activities.

Soil organic carbon loss decreases biodiversity but stimulates multitrophic interactions that promote belowground metabolism.

Soil organic carbon (SOC) plays an essential role in mediating community structure and metabolic activities of belowground biota. Unraveling the evolution of belowground communities and their feedback mechanisms on SOC dynamics helps embed the ecology of soil microbiome into carbon cycling, which serves to improve biodiversity conservation and carbon management strategy under global change. Here, croplands with a SOC gradient were used to understand how belowground metabolisms and SOC decomposition were linked to the diversity, composition, and co-occurrence networks of belowground communities encompassing archaea, bacteria, fungi, protists, and invertebrates. As SOC decreased, the diversity of prokaryotes and eukaryotes also decreased, but their network complexity showed contrasting patterns: prokaryotes increased due to intensified niche overlap, while that of eukaryotes decreased possibly because of greater dispersal limitation owing to the breakdown of macroaggregates. Despite the decrease in biodiversity and SOC stocks, the belowground metabolic capacity was enhanced as indicated by increased enzyme activity and decreased enzymatic stoichiometric imbalance. This could, in turn, expedite carbon loss through respiration, particularly in the slow-cycling pool. The enhanced belowground metabolic capacity was dominantly driven by greater multitrophic network complexity and particularly negative (competitive and predator-prey) associations, which fostered the stability of the belowground metacommunity. Interestingly, soil abiotic conditions including pH, aeration, and nutrient stocks, exhibited a less significant role. Overall, this study reveals a greater need for soil C resources across multitrophic levels to maintain metabolic functionality as declining SOC results in biodiversity loss. Our researchers highlight the importance of integrating belowground biological processes into models of SOC turnover, to improve agroecosystem functioning and carbon management in face of intensifying anthropogenic land-use and climate change.

Sustainable strategies: Nature-based solutions to tackle antibiotic resistance gene proliferation and improve agricultural productivity and soil quality.

The issue of antibiotic resistance is now recognized by the World Health Organisation (WHO) as one of the major problems in human health. Although its effects are evident in the healthcare settings, the root cause should be traced back to the One Health link, extending from animals to the environment. In fact, the use of organic fertilizers in agroecosystems represents one, if not the primary, cause of the introduction of antibiotics and antibiotic-resistant bacteria into the soil. Since the concentrations of antibiotics introduced into the soil are residual, the agroecosystem has become a perfect environment for the selection and proliferation of antibiotic resistance genes (ARGs). The continuous influx of these emerging contaminants (i.e., antibiotics) into the agroecosystem results in the selection and accumulation of ARGs in soil bacteria, occasionally giving rise to multi-resistant bacteria. These bacteria may harbour ARGs related to various antibiotics on their plasmids. In this context, these bacteria can potentially enter the human sphere when individuals consume food from contaminated agroecosystems, leading to the acquisition of multi-resistant bacteria. Once introduced into the nosocomial environment, these bacteria pose a significant threat to human health. In this review, we analyse how the use of digestate as an organic fertilizer can mitigate the spread of ARGs in agroecosystems. Furthermore, we highlight how, according to European guidelines, digestate can be considered a Nature-Based Solution (NBS). This NBS not only has the ability to mitigate the spread of ARGs in agroecosystems but also offers the opportunity to further improve Microbial-Based Solutions (MBS), with the aim of enhancing soil quality and productivity.

Selenium - An environmentally friendly micronutrient in agroecosystem in the modern era: An overview of 50-year findings.

Agricultural productivity is constantly being forced to maintain yield stability to feed the enormously growing world population. However, shrinking arable and nutrient-deprived soil and abiotic and biotic stressor (s) in different magnitudes put additional challenges to achieving global food security. Though well-defined, the concept of macro, micronutrients, and beneficial elements is from a plant nutritional perspective. Among various micronutrients, selenium (Se) is essential in small amounts for the life cycle of organisms, including crops. Selenium has the potential to improve soil health, leading to the improvement of productivity and crop quality. However, Se possesses an immense encouraging phenomenon when supplied within the threshold limit, also having wide variations. The supplementation of Se has exhibited promising outcomes in lessening biotic and abiotic stress in various crops. Besides, bulk form, nano-Se, and biogenic-Se also revealed some merits and limitations. Literature suggests that the possibilities of biogenic-Se in stress alleviation and fortifying foods are encouraging. In this article, apart from adopting a combination of a conventional extensive review of the literature and bibliometric analysis, the authors have assessed the journey of Se in the "soil to spoon" perspective in a diverse agroecosystem to highlight the research gap area. There is no doubt that the time has come to seriously consider the tag of beneficial elements associated with Se, especially in the drastic global climate change era.

Response mechanism of ecosystem gross primary productivity to cloud and aerosol changes in a Chinese winter-wheat cropland.

Changes in clouds and aerosols may alter the quantity of solar radiance and its diffuse components, as well as air temperature (Ta) and vapor pressure deficit (VPD), thereby affecting canopy photosynthesis. Our aim was to determine how ecosystem gross primary productivity (GPP) responds to the cloudiness and aerosol depth changes, as indicated by diffuse light fraction (fDIF). The environmental factors that caused these responses were examined using 2 years of eddy covariance data from a winter-wheat cropland in northern China. The GPP decreased significantly along with the fDIF in a nonlinear pattern, with a determination coefficient of 0.91. Changes in fDIF altered total photosynthetic active radiation (PAR), diffuse PAR, Ta and VPD. The variations in GPP with fDIF in both fDIF change Phase I (fDIF < 0.65) and Phase II (fDIF > 0.65) resulted from the combined effects of multiple environmental factors. Because the driving factors were closely correlated, a path analysis was used to distinguish their respective contribution to the GPP response to fDIF by integrating path coefficients. In Phases I and II, the decreased responses of GPP to fDIF were mainly caused by total PAR and diffuse PAR, respectively, which contributed approximately 49% and 37% to GPP variations, respectively. Our research has certain implications for the necessity to consider fDIF and to incorporate diffuse light into photosynthetic models.

Impact of agroecological practices on Phytoseiidae communities in a vineyard of South of France: effect of covercrops and agroforestry.

Viticulture is characterized by substantial pesticide applications, impacting natural enemies. New pest control strategies and management of plant diversity into agrosystems acting as reservoirs of natural enemies are assumed to limit pesticide use. Various studies support this hypothesis but gaps exist on the effect of diversification on Phytoseiidae mites, generalist predators reported as prevalent and efficient natural enemies in vineyards. This study focuses on the effect of cover crop management (no cover crop, spontaneous cover crops with or without agroforestry) and grape variety (resistant cv. Artaban and cv. Syrah) on predatory mites and prey communities, in a newly planted experimental vineyard in South-East France. Samplings were carried out three times a year on vine, cover crops, and co-planted trees. Phytoseiidae, Tydeiidae, Eriophyidae mites and thrips were characterized. Nine Phytoseiidae species were identified on vine, the main ones being Kampimodromus aberrans, Typhlodromus exhilaratus, Phytoseius finitimus and Euseius gallicus. Kampimodromus aberrans was prevalent on the cv. Syrah, highlighting a strong effect of variety. The low unexpected effect of system management observed outcome could be due to several factors, such as the experimental plot size or the influence of vine stress on Phytoseiidae communities in vines with cover crops. All phytoseiid species present on vine were identifed at least once on cover crops and co-planted trees, suggesting their potential role as reservoirs. Further studies should be performed investigating the evolution of communities in this newly-planted experimental system, as well as potential differences in trophic network interactions.

Impacts of climate change on winter wheat net primary production: the regulatory role of crop management.

BACKGROUND: The Huang-Huai-Hai Plain (3HP) is the main agricultural area in China. Although climate change (CC) and crop management (CM) are considered factors affecting the winter wheat net primary production (NPP) in this region, their effects remain unclear. In the present study, we evaluated the relative contributions of CC and CM to winter wheat aboveground NPP (ANPP) in the 3HP and the relationships between climatic factors and ANPP using the first-order difference method from 2000 to 2020. RESULTS: CM had a greater influence on the ANPP of winter wheat than did CC. However, the relative contribution of CM to ANPP gradually decreased in humid and dry sub-humid regions with the development of winter wheat. Furthermore, in areas characterized by low temperatures and limited precipitation, CC became the dominant factor contributing to ANPP, indicating that varieties resilient to drought and cold should be selected in these regions. Minimum and average temperatures were the dominant factors driving spatiotemporal variations in ANPP during the early stage of winter wheat growth, whereas maximum temperature constrained growth throughout the winter wheat growth cycle. When winter wheat entered the vigorous growth stage, precipitation and solar radiation replaced temperature as the driving factors influencing winter wheat growth. CONCLUSION: The results of the present study provide guidance for optimizing winter wheat crop management in the 3HP. © 2023 Society of Chemical Industry.

Coupled Oscillators in an Agroecosystem: Integrating Direct and Indirect Effects.

AbstractAgricultural pests are increasingly appreciated as subjects of ecology. One particular case, a pest in coffee production, is analyzed here using the conceptual framework of complex systems, increasingly acknowledged as having an obvious home in the field of ecology, notorious for its complex structures. The particular case analyzed here arguably falls under the control of the complexity of the ecological system rather than of a simple magic bullet of population regulation. The system, which has been under study in southern Mexico for the past quarter century, is analyzed through the lens of neutral oscillations of the classical nondissipative Lotka-Volterra system. Based on three consumer/resource pairs (populations of [1] an ant, [2] a scale insect, [3] a beetle predator of the scale insect, [4] a fungal pathogen of the scale insect, and [5] a fly parasitoid of the ant), this five-dimensional system is well known qualitatively. Coupling all agents through both direct effects and trait-mediated indirect effects, the behavior of the neutral oscillation form of the system reveals a complex set of behaviors, including harmonized invariant sets, chaos, and/or quasiperiodicity. Such behaviors are well-known subjects in the science of complex systems and, it is argued, are ultimately sufficient to effect a degree of regulation on the pest, independent of explicit density-dependent feedback. Control of the system is thus seen as arguably actuated through its complexity, independent of any classic dissipative force.

Sunflower plantings reduce a common gut pathogen and increase queen production in common eastern bumblebee colonies.

Community diversity can reduce the prevalence and spread of disease, but certain species may play a disproportionate role in diluting or amplifying pathogens. Flowers act as both sources of nutrition and sites of pathogen transmission, but the effects of specific plant species in shaping bee disease dynamics are not well understood. We evaluated whether plantings of sunflower (Helianthus annuus), whose pollen reduces infection by some pathogens when fed to bees in captivity, lowered pathogen levels and increased reproduction in free-foraging bumblebee colonies (Bombus impatiens). Sunflower abundance reduced the prevalence of a common gut pathogen, Crithidia bombi, and reduced infection intensity, with an order of magnitude lower infection intensity at high sunflower sites compared with sites with little to no sunflower. Sunflower abundance was also positively associated with greater queen production in colonies. Sunflower did not affect prevalence of other detected pathogens. This work demonstrates that a single plant species can drive disease dynamics in foraging B. impatiens, and that sunflower plantings can be used as a tool for mitigating a prevalent pathogen while also increasing reproduction of an agriculturally important bee species.

Wild Bee Exposure to Pesticides in Conservation Grasslands Increases along an Agricultural Gradient: A Tale of Two Sample Types.

Conservation efforts have been implemented in agroecosystems to enhance pollinator diversity by creating grassland habitat, but little is known about the exposure of bees to pesticides while foraging in these grassland fields. Pesticide exposure was assessed in 24 conservation grassland fields along an agricultural gradient at two time points (July and August) using silicone band passive samplers (nonlethal) and bee tissues (lethal). Overall, 46 pesticides were detected including 9 herbicides, 19 insecticides, 17 fungicides, and a plant growth regulator. For the bands, there were more frequent/higher concentrations of herbicides in July (maximum: 1600 ng/band in July; 570 ng/band in August), while insecticides and fungicides had more frequent/higher concentrations in August (maximum: 110 and 65 ng/band in July; 1500 and 1700 ng/band in August). Pesticide concentrations in bands increased 16% with every 10% increase in cultivated crops. The bee tissues showed no difference in detection frequency, and concentrations were similar among months; maximum concentrations of herbicides, insecticides, and fungicides in July and August were 17, 27, and 180 and 19, 120, and 170 ng/g, respectively. Pesticide residues in bands and bee tissues did not always show the same patterns; of the 20 compounds observed in both media, six (primarily fungicides) showed a detection-concentration relationship between the two media. Together, the band and bee residue data can provide a more complete understanding of pesticide exposure and accumulation in conserved grasslands.

Speciation of macro- and nanoparticles of Cr2O3 in Hordeum vulgare L. and subsequent toxicity: A comparative study.

Chromium (Cr) is reported to be hazardous to environmental components and surrounding biota when levels exceed allowable thresholds. As Cr is extensively utilized in different industries, thereby comprehensively studied for its toxicity. Along with Cr, the applications of nano-Cr or chromium oxide nanoparticles (Cr2O3-NPs) are also expanding; however, the literature is scarce or limited on their phytotoxicity. Thereby, the current work investigated the morpho-physiological insights of macro- and nanoparticles of Cr in Hordeum vulgare L. plants. The increased accumulation and translocation of Cr under the exposure of both forms disturbed the cellular metabolism that might have inhibited germination and growth as well as interfered with the photosynthesis of plants. The overall extent of toxicity was noticeably higher under nanoparticles' exposure than macroparticles of Cr. The potential cue for such phytotoxic consequences mediated by Cr nanoparticles could be an increased bioavailability of Cr ions which was also supported by their total content, mobility, and factor toxicity index. Besides, to support further these findings, synchrotron X-ray technique was used to reliably identify Cr-containing compounds in the plant tissues. The X-ray spectra of the near spectral region and the far region of the spectrum of K-edge of Cr were obtained, and it was established that the dominant crystalline phase corresponds to Cr2O3 (eskolaite) from the recorded observations. Thus, the obtained results would allow revealing the mechanism of macro- and nanoparticles of Cr induced impacts on plant at the tissue, cellular- and sub-cellular levels.

Multi-omics analysis on an agroecosystem reveals the significant role of organic nitrogen to increase agricultural crop yield.

Both inorganic fertilizer inputs and crop yields have increased globally, with the concurrent increase in the pollution of water bodies due to nitrogen leaching from soils. Designing agroecosystems that are environmentally friendly is urgently required. Since agroecosystems are highly complex and consist of entangled webs of interactions between plants, microbes, and soils, identifying critical components in crop production remain elusive. To understand the network structure in agroecosystems engineered by several farming methods, including environmentally friendly soil solarization, we utilized a multiomics approach on a field planted with Brassica rapa We found that the soil solarization increased plant shoot biomass irrespective of the type of fertilizer applied. Our multiomics and integrated informatics revealed complex interactions in the agroecosystem showing multiple network modules represented by plant traits heterogeneously associated with soil metabolites, minerals, and microbes. Unexpectedly, we identified soil organic nitrogen induced by soil solarization as one of the key components to increase crop yield. A germ-free plant in vitro assay and a pot experiment using arable soils confirmed that specific organic nitrogen, namely alanine and choline, directly increased plant biomass by acting as a nitrogen source and a biologically active compound. Thus, our study provides evidence at the agroecosystem level that organic nitrogen plays a key role in plant growth.

Effects of agricultural landscape structure and canola coverage on biochemical and physiological traits of the ground beetle Poecilus cupreus.

The intensifications in the agricultural landscape and the application of pesticides can cause adverse effects on the fitness of organisms in that landscape. Here, we investigated whether habitats with different agricultural pressures influenced acetylcholinesterase (AChE) activity - a biomarker for exposure to pesticides, respiration rate, and resistance to starvation in the ground beetle Poecilus cupreus. Two differently structured landscapes were selected for the study, one dominated by small (S) and another by large (L) fields. Within each landscape three habitat types were selected: in the S landscape, these were habitats with medium (M), small (S) and no canola (meadow, 0) coverage (i.e., SM, SS, S0), and in the L landscape habitats with large (L), medium (M) and no canola (meadow, 0) coverage (i.e., LL, LM, L0), representing different levels of agricultural pressure. The activity of AChE was the highest in beetles from canola-free habitats (S0 and L0), being significantly higher than in beetles from the SM and SS habitats. The mean respiration rate corrected for body mass was also the highest in S0 and L0 beetles, with significant differences between populations from L0 vs. SS and from S0 vs. SS. Only beetles from S0, SS, L0, and LM were numerous enough to assess the resistance to starvation. Individuals from the LM habitat showed better survival compared to the canola-free habitat in the same landscape (L0), whereas in S landscape the SS beetles survived worse than those from S0, suggesting that characteristics of L landscape may lead to developing mechanisms of starvation resistance of P. cupreus in response to agricultural pressure.

Abundance, spatial distribution, and characteristics of microplastics in agricultural soils and their relationship with contributing factors.

Agro-ecosystem contamination with microplastics (MPs) is of great concern. However, limited research has been conducted on the agricultural soil of tropical regions. This paper investigated MPs in the agro-ecosystem of Hainan Island, China, as well as their relationships with plastic mulching, farming practices, and social and environmental factors. The concentration of MPs in the study area ranged from 2800 to 82500 particles/kg with a mean concentration of 15461.52 particles/kg. MPs with sizes between 20 and 200 µm had the highest abundance of 57.57%, fragment (58.16%) was the most predominant shape, while black (77.76%) was the most abundant MP colour. Polyethylene (PE) (71.04%) and polypropylene (PP) (19.83%) were the main types of polymers. The mean abundance of MPs was significantly positively correlated (p < 0.01) with all sizes, temperature, and shapes except fibre, while weakly positively correlated with the population (p = 0.21), GDP (p = 0.33), and annual precipitation (p = 0.66). In conclusion, plastic mulching contributed to significant contamination of soil MPs in the study area, while environmental and social factors promoted soil MPs fragmentation. The current study results indicate serious contamination with MPs, which poses a concern regarding ecological and environmental safety.

Quantitative Representativeness and Constituency of the Long-Term Agroecosystem Research Network and Analysis of Complementarity with Existing Ecological Networks.

Studies conducted at sites across ecological research networks usually strive to scale their results to larger areas, trying to reach conclusions that are valid throughout larger enclosing regions. Network representativeness and constituency can show how well conditions at sampling locations represent conditions also found elsewhere and can be used to help scale-up results over larger regions. Multivariate statistical methods have been used to design networks and select sites that optimize regional representation, thereby maximizing the value of datasets and research. However, in networks created from already established sites, an immediate challenge is to understand how well existing sites represent the range of environments in the whole area of interest. We performed an analysis to show how well sites in the USDA Long-Term Agroecosystem Research (LTAR) Network represent all agricultural working lands within the conterminous United States (CONUS). Our analysis of 18 LTAR sites, based on 15 climatic and edaphic characteristics, produced maps of representativeness and constituency. Representativeness of the LTAR sites was quantified through an exhaustive pairwise Euclidean distance calculation in multivariate space, between the locations of experiments within each LTAR site and every 1 km cell across the CONUS. Network representativeness is from the perspective of all CONUS locations, but we also considered the perspective from each LTAR site. For every LTAR site, we identified the region that is best represented by that particular site-its constituency-as the set of 1 km grid locations best represented by the environmental drivers at that particular LTAR site. Representativeness shows how well the combination of characteristics at each CONUS location was represented by the LTAR sites' environments, while constituency shows which LTAR site was the closest match for each location. LTAR representativeness was good across most of the CONUS. Representativeness for croplands was higher than for grazinglands, probably because croplands have more specific environmental criteria. Constituencies resemble ecoregions but have their environmental conditions "centered" on those at particular existing LTAR sites. Constituency of LTAR sites can be used to prioritize the locations of experimental research at or even within particular sites, or to identify the extents that can likely be included when generalizing knowledge across larger regions of the CONUS. Sites with a large constituency have generalist environments, while those with smaller constituency areas have more specialized environmental combinations. These "specialist" sites are the best representatives for smaller, more unusual areas. The potential of sharing complementary sites from the Long-Term Ecological Research (LTER) Network and the National Ecological Observatory Network (NEON) to boost representativeness was also explored. LTAR network representativeness would benefit from borrowing several NEON sites and the Sevilleta LTER site. Later network additions must include such specialist sites that are targeted to represent unique missing environments. While this analysis exhaustively considered principal environmental characteristics related to production on working lands, we did not consider the focal agronomic systems under study, or their socio-economic context.

Enhancing Indigenous Food Sovereignty and Community Health Through the Karuk Agroecosystem Resilience Initiative: We Are Caring for It: xúus nu'éethti.

Indigenous communities in the United States experience some of the highest rates of food insecurity and diet-related diseases despite an abundance of food assistance programs and other public health interventions. New approaches that center Indigenous perspectives and solutions are emerging and urgently needed to better understand and address these challenges. This Practice Note shares lessons learned from ongoing collaboration between the Karuk Tribe and University of California, Berkeley researchers and other partners to assess and enhance food sovereignty among Tribes and Tribal communities in the Klamath River Basin. Through two participatory research and extension projects, we demonstrate the importance of centering Indigenous knowledge to strengthen research findings and identify more culturally appropriate solutions to community identified food access, health, and ecosystem challenges. Key findings suggest that approaches to food sovereignty and community health must emanate from the community, be approached holistically, reflect community values and priorities, and center Indigenous land stewardship.

Population dynamics of Meloidogyne graminicola in soil in different types of direct-seeded rice agroecosystems in Hunan Province, China.

The rice root-knot nematode Meloidogyne graminicola is increasingly widely distributed in China and has had a severe incidence in Hunan Province. It is thus necessary to investigate its population dynamics in paddy fields. This study was conducted to ascertain the effect of direct-seeded rice agroecosystems on the population dynamics of M. graminicola and root gall development in rice. The results indicated that the population density of M. graminicola in soil was markedly influenced by the agroecosystem, rainfall and temperature. The population density of M. graminicola J2, and eggs in the soil and root galls, were significantly larger in the dry aerobic rice agroecosystem and in the rain-fed upland agroecosystem than in the lowland double-rice cropping sequence agroecosystem. As it can affect soil moisture rainfall was the key factor affecting the density of nematodes in both the rain-fed upland agroecosystem and the dry aerobic rice agroecosystem. Field flooding was still an effective way to reduce the population density of M. graminicola. In addition, we observed that M. graminicola can lay eggs outside rice roots under laboratory conditions. Therefore, we propose a hypothesis that M. graminicola lays egg masses within roots when the soil moisture is high, but lays eggs outside when the soil moisture is suitable. By clarifying the population dynamics of M. graminicola in different types of direct-seeded rice agroecosystems, this study is conducive to controlling rice root-knot nematodes.

Assessing the energy trap of industrial agriculture in North America and Europe: 82 balances from 1830 to 2012.

Early energy analyses of agriculture revealed that behind higher labor and land productivity of industrial farming, there was a decrease in energy returns on energy (EROI) invested, in comparison to more traditional organic agricultural systems. Studies on recent trends show that efficiency gains in production and use of inputs have again somewhat improved energy returns. However, most of these agricultural energy studies have focused only on external inputs at the crop level, concealing the important role of internal biomass flows that livestock and forestry recirculate within agroecosystems. Here, we synthesize the results of 82 farm systems in North America and Europe from 1830 to 2012 that for the first time show the changing energy profiles of agroecosystems, including livestock and forestry, with a multi-EROI approach that accounts for the energy returns on external inputs, on internal biomass reuses, and on all inputs invested. With this historical circular bioeconomic approach, we found a general trend towards much lower external returns, little or no increases in internal returns, and almost no improvement in total returns. This "energy trap" was driven by shifts towards a growing dependence of crop production on fossil-fueled external inputs, much more intensive livestock production based on feed grains, less forestry, and a structural disintegration of agroecosystem components by increasingly linear industrial farm managements. We conclude that overcoming the energy trap requires nature-based solutions to reduce current dependence on fossil-fueled external industrial inputs and increase the circularity and complexity of agroecosystems to provide healthier diets with less animal products. Supplementary Information: The online version contains supplementary material available at 10.1007/s13593-023-00925-5.

Pesticide resistance in arthropods: Ecology matters too.

Pesticide resistance development is an example of rapid contemporary evolution that poses immense challenges for agriculture. It typically evolves due to the strong directional selection that pesticide treatments exert on herbivorous arthropods. However, recent research suggests that some species are more prone to evolve pesticide resistance than others due to their evolutionary history and standing genetic variation. Generalist species might develop pesticide resistance especially rapidly due to pre-adaptation to handle a wide array of plant allelochemicals. Moreover, research has shown that adaptation to novel host plants could lead to increased pesticide resistance. Exploring such cross-resistance between host plant range evolution and pesticide resistance development from an ecological perspective is needed to understand its causes and consequences better. Much research has, however, been devoted to the molecular mechanisms underlying pesticide resistance while both the ecological contexts that could facilitate resistance evolution and the ecological consequences of cross-resistance have been under-studied. Here, we take an eco-evolutionary approach and discuss circumstances that may facilitate cross-resistance in arthropods and the consequences cross-resistance may have for plant-arthropod interactions in both target and non-target species and species interactions. Furthermore, we suggest future research avenues and practical implications of an increased ecological understanding of pesticide resistance evolution.

Remarkable effects of microbial factors on soil phosphorus bioavailability: A country-scale study.

Low soil phosphorus (P) bioavailability causes the widespread occurrence of P-limited terrestrial ecosystems around the globe. Exploring the factors influencing soil P bioavailability at large spatial scales is critical for managing these ecosystems. However, previous studies have mostly focused on abiotic factors. In this study, we explored the effects of microbial factors on soil P bioavailability of terrestrial ecosystems using a country-scale sampling effort. Our results showed that soil microbial biomass carbon (MBC) and acid phosphatase were important predictors of soil P bioavailability of agro- and natural ecosystems across China although they appeared less important than total soil P. The two microbial factors had a positive effect on soil P bioavailability of both ecosystem types and were able to mediate the effects of several abiotic factors (e.g., mean annual temperature). Meanwhile, we revealed that soil phytase could affect soil P bioavailability at the country scale via ways similar to those of soil MBC and acid phosphatase, a pattern being more pronounced in agroecosystems than in natural ecosystems. Moreover, we obtained evidence for the positive effects of microbial genes encoding these enzymes on soil P bioavailability at the country scale although their effect sizes varied between the two ecosystem types. Taken together, this study demonstrated the remarkable effects of microbial factors on soil P bioavailability at a large spatial scale, highlighting the importance to consider microbial factors in managing the widespread P-limited terrestrial ecosystems.