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Plant economics, the way plants allocate and utilize resources, affect multiple soil processes through interactions with root and associated microbial communities. However, the interplay between plant economics and microbial ecological strategies remains poorly understood, which is crucial for integrated manipulation of plant‐ and microbe‐mediated functions in mitigating climate change and sustaining soil health.We used a field experiment with 11 cover crop species grown monocultures in the same base soil to test whether microbial ecological strategies are associated with plant economic strategies and if their interactions are linked to soil functions. A principal component analysis (PCA) was performed on root and leaf traits to identify the loadings of cover crop species on the plant trait space. Metagenomic analysis of rhizosphere microbial communities was conducted to infer their ecological strategies based on genetically encoded community‐aggregated traits.We found a synchronous relationship between the conservation gradient of plant economic strategies and the trade‐offs in microbial ecological strategies. Conservative plant strategists, such as Lolium multiflorum, Triticum turgidum and Brassica juncea, fostered microbial communities characterized by high growth yield potentials (Y‐strategies). This included increased microbial carbon fixation pathways, citrate cycle, ribosome and valine, leucine and isoleucine biosynthesis. As a result, microbial metabolic efficiency improved, shown by higher microbial biomass carbon content and a lower metabolic quotient (qCO2), led to enhanced soil organic carbon accumulation. In comparison, acquisitive plants like Astragalus sinicus, Vicia villosa, Trifolium incarnatum and Medicago sativa stimulated microbial resource‐acquisition strategies (A‐strategies). This included enhanced bacterial chemotaxis, secretion systems, biotin metabolism and cell motility pathways, which in turn increased soil exoenzyme activity and accelerated soil nitrogen mineralization. Consequently, these species enhanced soil nitrogen availability and had substantial feedbacks on subsequent main crop productivity.Synthesis. This study demonstrates how plant economic strategies influence the balance between different microbial ecological strategies, specifically the trade‐offs in Y‐ and A‐strategies. These interactions exert control over carbon and nitrogen dynamics in the soil ecosystem. The findings provide insights for implementing nature‐based solutions to improve agroecosystem management practices. [ABSTRACT FROM AUTHOR]

The soil physico-chemical characteristics, including the oxidation-reduction (redox) potential (ORP), pH (acid-base reactions), and temperature, are essential for all soil organisms, and in turn, influence fluctuations of these parameters within the soil substrate. This study aimed to compare the mutual effects of soil physico-chemical properties and plant performance under cultivation, with and without a soil covering (mulch) in interrow soil. The investigation was conducted over a complete growing season in an agricultural setup using two model crops - Solanum tuberosum L. (potato) and Phaseolus vulgaris L. (bush bean). Throughout our field work in a high-altitude region of Rhodope Mountains, ORP showed a negative correlation with both pH and temperature. We also observed an interdependence between ORP and plant growth. Specifically, ORP values tended to decrease compared to control setups without plants, depending on the plant species and their developmental stages. Mulching significantly reduced ORP, indicating enhanced redox processes driven by soil organism activity. In the presence of mulch, S. tuberosum displayed slight increases in leaf dimensions, chlorophyll content, and electron transport efficiency in the thylakoids, while the effects on P. vulgaris were much less pronounced. Overall, the data highlighted ORP as a sensitive indicator of soil state, with mulching improving both soil regeneration and plant performance. Our findings contribute to the understanding of plant-soil interactions, supporting sustainable agricultural practices. [ABSTRACT FROM AUTHOR]

Forecasts of root growth and carbon sequestration under global change are compromised by uncertainty in how plants will allocate biomass between above and belowground pools. Here, we develop a simple model to assess whether functional balance theory can explain a complex biomass allocation response observed in a brackish marsh under experimental warming and elevated CO2. Our model shows how treatment‐driven changes in nitrogen supply and demand can explain divergent observations of root growth (i.e., maximum responses under intermediate warming and elevated CO2). The model also reveals a surprising interaction between warming and eutrophication, where enhanced N loading to coastal marshes may reduce adverse impacts of warming on root growth. Our findings provide a mechanistic basis for incorporating biomass allocation into forecast models of marsh evolution. They also provide a general example of using ecological theory to decompose complex net responses observed in multi‐factor global change experiments into constituent processes. Plain Language Summary: Uncertain adjustments in how plants allocate new biomass between roots and shoots cause disagreement about the degree to which global plants will increase carbon sequestration under climate change. These biomass allocation adjustments are especially important in coastal marshes, among the strongest carbon sinks on Earth and vulnerable to sea‐level rise. Here, marsh plants increase rates of soil building through both extensive root growth and shoot‐driven enhancement of sediment deposition. We use theory of how plants optimize resource acquisition as resource availability changes to develop a simple model that links marsh biomass allocation to nitrogen cycling. We then use this model to explain surprising, non‐linear responses of biomass allocation observed in a global change experiment that actively warmed and elevated CO2 in a brackish marsh. Finally, we use the model show that negative impacts of warming on root growth may be reduced by nutrient pollution, a controversial topic traditionally linked to marsh degradation and associated reductions in carbon sequestration. Altogether, our verified model will inform the incorporation of these nutrient‐mediated adjustments in plant physiology into the models that describe how plants impact coastal soil building, improving our ability to predict the response of many coastal ecosystems to climate change. Key Points: A simple model shows how resource optimization theory can explain a non‐linear response in biomass allocation to warming and elevated CO2The model also indicates eutrophication may reduce adverse impacts of warming on root growthOur work informs incorporation of biomass allocation adjustments into models of accretion and carbon dynamics under climate change [ABSTRACT FROM AUTHOR]

Plant–soil feedback (PSF) plays a key role in determining the composition of plant communities, and understanding the impact of the ongoing climate change on PSF is thus crucial for predicting the consequences of climate change for ecosystems. Here, we conducted a growth‐chamber experiment to examine possible climate‐driven shifts in PSF of a perennial grass, Festuca rubra, originating from two climatically distinct sites, by using all factorial combinations of soil biota origin, plant origin, and cultivation climate. Soil biota generated more negative PSF effects when grown under the climatic conditions of their origin. This observation suggests that soil biota, especially soil pathogens, are well adapted to their local climate, exhibiting greater efficiency in suppressing plant growth within their climatic conditions. All plants, regardless of their origin, exhibited less negative PSF (expressed as relative performance in live vs. sterilized soil) when grown under warmer climate than under colder climate, likely due to positive effects of increased activity of soil decomposers and enhanced nutrient cycling. Plants showed negative PSF when grown with local soil biota under home climate, and the negative PSF disappeared when plants were grown with foreign biota or in away climates. This suggests that any disruption of the established plant‐soil‐climate interactions may lead to the release of plants from negative PSF, potentially destabilizing plant communities. Synthesis. Our results highlight the adaptions of soil biota to their native climate as key drivers of plant–soil feedback interactions and suggest that climate change could significantly alter these interactions, potentially leading to new plant community dynamics. These findings emphasize the need for further investigations to unravel the mechanisms driving these responses and evaluate their consequences for ecosystem resilience in the face of climate change. [ABSTRACT FROM AUTHOR]

Microplastics (MP) are recognized as a major pollutant in terrestrial environments, prompting concerns about their effects on plant–soil dynamics. Despite evidence of MP altering soil physicochemical properties, impacts on belowground root traits and arbuscular mycorrhizal (AM) fungi remain poorly explored. Existing research has mainly centred on a few model plant species, emphasizing root biomass, and often employs single polymer types and addition rates that surpass realistic scenarios.To investigate how environmentally relevant mixtures and concentrations of MPs impact plant growth, root trait expression and AM fungal colonization, we conducted a greenhouse experiment using six plant species chosen for their contrasting root life strategies; three species in the Amaryllidaceae family represented resource conservation root traits (Allium fistulosum (onion), Allium tuberosum (chive), Allium porrum (leek)), and three from the Solanaceae family, represented plants with resource acquisitive root traits (Solanum lycopersicum (tomato), Solanum melongena (eggplant), Capsicum annuum (pepper)). MP treatments consisted of control (0% MP), low (0.1% w/w) and high (1% w/w) MP additions, using an environmentally relevant MP mixture of weathered polymer types and shapes. We measured above and belowground biomass, average root trait expression (specific root length (SRL), average root diameter (D) and root tissue density (RTD)), AM fungal colonization, as well as intraspecific variability across MP addition treatments.We found that responses to environmentally relevant additions of MPs were species specific and not determined by root life‐strategy. MPs increased biomass in leek, eggplant and tomato, while decreasing AM fungal colonization in tomato. MP additions had no discernible impact on average root functional trait expression across species. However, the addition of MPs resulted in altered intraspecific variability in root traits and AM fungal colonization, indicating a mechanism for plant tolerance to MPs.To address the impacts of MPs on plant functioning, research needs to focus on environmentally relevant mixtures of MPs, considering various plant species' capacities to tolerate soil contamination and the potential for tipping points under real‐world conditions. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Terrestrial plant communities often become invaded by alien species, which may benefit from high growth rates, strong phenotypic plasticity and reduced negative impacts from local soil communities. At the same time, terrestrial communities are increasingly more often exposed to periods of drought. However, how drought affects the competition between alien and native plants directly, and indirectly, through changing impacts of soil communities on plant performance, remains poorly understood.Here, we performed a greenhouse pot experiment in which we examined biomass responses of five native and five naturalized alien species (all occurring in mesic grasslands) to drought and benign soil moisture conditions, while growing in interspecific, intraspecific or absence of competition, in the presence or absence of native soil biota. We expected that alien plant species are less negatively affected by soil biota, but more negatively affected by drought than native species, and that drought indirectly weakens soil‐community‐driven competitive benefits of alien plant species over native ones.On average, soil‐community effects on plant biomass were positive, but native performance was less positively affected by soil communities than alien performance, suggesting reduced impacts of soil‐borne enemies on alien plants. Drought more negatively affected alien‐ than native plant performance. Drought impacts on plant biomass did not depend on soil community presence, but in the presence of soil biota, plants overall invested more in root biomass when exposed to drought. The effects of competition were subtle and species‐specific.To better understand the observed positive soil‐community effects on plant performance in our study, we examined mycorrhizal root colonization of plants grown in absence of competition. Among‐species variation in mycorrhizal colonization explained plant performance differences between soils with and without live soil communities, indicating a key role for arbuscular mycorrhizal fungi as driver of plant performance. However, mycorrhizal colonization did not differ between alien and native plants and was unaffected by drought.Overall, our study suggests that drought may weaken alien plant invasions through stronger direct negative impacts on alien than on native plant performance, but that drought does not affect soil‐biota‐driven differences in plant performance between alien and native plants. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Soil microbes have long been recognized to substantially affect the coexistence of pairwise plant species across terrestrial ecosystems. However, projecting their impacts on the coexistence of multispecies plant systems remains a pressing challenge. To address this challenge, we conducted a greenhouse experiment with 540 seedlings of five tree species in a subtropical forest in China and evaluated microbial effects on multispecies coexistence using the structural method, which quantifies how the structure of species interactions influences the likelihood for multiple species to persist. Specifically, we grew seedlings alone or with competitors in different microbial contexts and fitted individual biomass to a population dynamic model to calculate intra‐ and interspecific interaction strength with and without soil microbes. We then used these interaction structures to calculate two metrics of multispecies coexistence, structural niche differences (which promote coexistence) and structural fitness differences (which drive exclusion), for all possible communities comprising two to five plant species. We found that soil microbes generally increased both the structural niche and fitness differences across all communities, with a much stronger effect on structural fitness differences. A further examination of functional traits between plant species pairs found that trait differences are stronger predictors of structural niche differences than of structural fitness differences, and that soil microbes have the potential to change trait‐mediated plant interactions. Our findings underscore that soil microbes strongly influence the coexistence of multispecies plant systems, and also add to the experimental evidence that the influence is more on fitness differences rather than on niche differences. [ABSTRACT FROM AUTHOR]

In future cropping systems, a focus on belowground plant–soil interactions should exploit the synergy of plant responses to multiple soil factors to maximize the biological potential of roots. Key soil factors include root-zone heterogeneity arising from the physical, biological, and chemical properties varying in time and space. Optimizing the match between root functioning and soil properties is needed to achieve increased crop productivity and improved soil health. The integration of plant and soil sciences, and the application of holistic plant–soil solutions in the crop systems, will provide effective new approaches towards a more sustainable crop production. The Green Revolution transformed agriculture with high-yielding, stress-resistant varieties. However, the urgent need for more sustainable agricultural development presents new challenges: increasing crop yield, improving nutritional quality, and enhancing resource-use efficiency. Soil plays a vital role in crop-production systems and ecosystem services, providing water, nutrients, and physical anchorage for crop growth. Despite advancements in plant and soil sciences, our understanding of belowground plant–soil interactions, which impact both crop performance and soil health, remains limited. Here, we argue that a lack of understanding of these plant–soil interactions hinders sustainable crop production. We propose that targeted engineering of crops and soils can provide a fresh approach to achieve higher yields, more efficient sustainable crop production, and improved soil health. [ABSTRACT FROM AUTHOR]

Crop diversification offers numerous synergistic advantages over intensive monocultures via belowground interspecific interactions. The plant–soil–microbiome interactions that trigger cascading effects underpin the benefits of crop diversification. Unlocking the potential of cascading effects in diversified cropping systems can alleviate common obstacles in intensive monoculture farming. Strategically selecting species and varieties that complement and facilitate one another can enhance agricultural productivity with fewer agrochemical inputs. Crop diversification practices offer numerous synergistic benefits. So far, research has traditionally been confined to exploring isolated, unidirectional single-process interactions among plants, soil, and microorganisms. Here, we present a novel and systematic perspective, unveiling the intricate web of plant–soil–microbiome interactions that trigger cascading effects. Applying the principles of cascading interactions can be an alternative way to overcome soil obstacles such as soil compaction and soil pathogen pressure. Finally, we introduce a research framework comprising the design of diversified cropping systems by including commercial varieties and crops with resource-efficient traits, the exploration of cascading effects, and the innovation of field management. We propose that this provides theoretical and methodological insights that can reveal new mechanisms by which crop diversity increases productivity. [ABSTRACT FROM AUTHOR]

Termites—one of the most abundant animal groups in tropical ecosystems—are vital in nutrient recycling, contributing significantly to maintaining ecosystem functioning. However, how selective they are in their litter food choice, and whether they prefer nutritious or less nutritious litter substrates, are still important unresolved questions.Here, we test the effect of litter traits on the removal of litter by fungus‐growing termites, a dominant group of macrodetritivores in the Serengeti‐Mara ecosystem. We used metal‐mesh litterbags to measure the mass loss of stem and leaf litter from 23 grass species after an incubation period of 61 days.Sheeting—soil deposits indicating termite presence—strongly increased with tannin and phenolic compounds, especially in leaf litter (R2 = 0.54), where highly aromatic species like Cymbopogon caesius and Bothriochloa insculpta exhibited the highest sheeting rates. Litterbags with sheeting displayed 66% higher mass loss on average compared to those without. Once termites had selected the substrate, mass loss increased consistently irrespective of litter traits.Quantifying the combined effects of sheeting frequency and differential mass loss, we found that fungus‐growing termites predominantly increased the mass loss of high‐nutrient litter. This was mainly due to additional mass loss in leaf litter, not stem litter, with tannin concentration being the primary predictor of enhanced overall decomposition by termites. This suggests termites ameliorate the otherwise adverse influence of plant secondary compounds on litter decomposition.Synthesis: Our results support the idea that fungus‐growing termites are generalists, as termites collected organic substrates with varying quality. The strong effect of phenolic compounds on sheeting rate implies that secondary compounds play an important role in termite substrate selection. The selective removal of substrates high in secondary compounds suggests fungus‐growing termites lift important constraints to microbial breakdown, potentially enhancing ecosystem‐level carbon and nutrient recycling rates. Termites play crucial roles in recycling organic matter across tropical biomes and our study highlights that the role of secondary compounds in their selection and detection in decomposition studies needs more attention [ABSTRACT FROM AUTHOR]

Plant–soil interactions have bottom–up and top–down effects within a plant community. Heavy metal pollution can change plant–soil interactions, directly influence bottom–up effects and indirectly affect herbivores within the community. In turn, herbivores can affect plant–soil interactions through top–down effects. However, the combined effects of heavy metals and herbivores on soil enzymes, plants and herbivores have rarely been reported. Therefore, the effects of lead (Pb), Spodoptera litura and their combined effects on soil enzyme activities, pakchoi nutrition, defence compounds and S. litura fitness were examined here. Results showed that Pb, S. litura and their combined effects significantly affected soil enzymes, pakchoi and S. litura. Specifically, exposure to double stress (Pb and S. litura) decreased soil urease, phosphatase and sucrase activities compared with controls. Furthermore, the soluble protein and sugar contents of pakchoi decreased, and the trypsin inhibitor content and antioxidant enzyme activity increased. Finally, the S. litura development period was extended, and survival, emergence rates and body weight decreased after exposure to double stress. The combined stress of Pb and S. litura significantly decreased soil enzyme activities. Heavy metal accumulation in plants may create a superposition or synergistic effect with heavy metal-mediated plant chemical defence, further suppressing herbivore development. Pb, S. litura and their combined effects inhibited soil enzyme activities, improved pakchoi resistance and reduced S. litura development. The results reveal details of soil–plant–herbivore interactions and provide a reference for crop pest control management in the presence of heavy metal pollution. [ABSTRACT FROM AUTHOR]

Earthworms benefit plant growth and play a vital role in shaping soil microbial communities. However, how earthworms modify the soil microorganisms and thus affect plant growth is still unclear. Although fertilizers alter the assembly of microbial communities, further investigations are required to test the effect of fertilizer type on the relationship between earthworms, soil microbial communities and plants.We evaluated the role of earthworms in soil microorganisms and maize plant growth characteristics under organic or chemical fertilizers in field and greenhouse experiments. We explored the relationships between earthworms, soil microbial community and plant growth under different fertilizer types.We found that the presence of earthworms promoted plant growth, increased the amount of plant root exudates, and enhanced the connections between rhizosphere bacterial, fungal and protist communities. Both earthworms and fertilizer application significantly changed the structure of soil bacterial, fungal and protist communities. The complexity of the soil microbial community network increased under organic, compared to chemical fertilizer application. The greenhouse experiment showed that the effect of earthworms on plant growth was weakened when maize plants were grown in sterilized soil under organic or chemical fertilizers.Synthesis and applications: Our study provides solid evidence that earthworms largely depend on soil microorganisms for their effects on plants under the application of different fertilizer conditions. This may provide new insights into reducing the amounts of fertilizer used by enhancing the role of earthworms and soil microorganisms. [ABSTRACT FROM AUTHOR]

Janzen-Connell effects state that the accumulation of host-specific natural enemies near parent plants can negatively affect their offspring. Negative plant-soil feedbacks can produce patterns of seedling performance predicted by Janzen-Connell effects and influence plant populations, but their relevance in field conditions remains unclear. Here, using spatial point-pattern analysis, we examine the spatial distribution of Jacobaea vulgaris to assess whether distance- and density-dependent predictions of Janzen-Connell effects are evident in the field. We established 27 replicated 64 m2 plots at two grassland sites and mapped positions of rosette-bearing and flowering J. vulgaris plants within each plot. To investigate temporal distribution patterns, we tracked plant positions repeatedly in three plots during a single season. Additionally, we tested whether these patterns are soil-mediated. Soil samples were collected underneath flowering plants and at a distance of 0.5 meter, and used to compare seed germination, seedling survival, and growth under controlled conditions. Furthermore, we measured J. vulgaris growth in soil from patches with high J. vulgaris densities and in soil from areas outside these patches. The density of rosette-bearing plants was lower at close distances from flowering plants than expected from null models, suggesting negative distance-dependent plant recruitment. The degree of clustering decreased over time from rosette-bearing to flowering plants, indicating density-dependent self-thinning. Seed germination was higher in soil further away from flowering J. vulgaris plants than in soil underneath plants at one site, but soil distance was not an overall significant factor in explaining seed germination. However, seedling mortality and biomass did not differ between soils collected at the two distances, and plants produced similar biomass in soil collected from inside and outside J. vulgaris patches. Our study demonstrates conspecific distance- and density-dependent plant recruitment in J. vulgaris in the field, but we found no evidence this depends on belowground natural enemies.

Lianas, or woody vines, are key components of many tropical forests and can have substantial impacts on the dynamics and functioning of these important ecosystems. Their competition with trees for resources, in particular light, can hamper the recovery of forests from disturbances. Yet, it is unclear how forest disturbance interacts with liana–tree ratio (LTR), topography and soil properties to shape tree dynamics and the trajectories of forest succession.Using temporal data from the Kilombero Valley and the Udzungwa Mountains of Tanzania, we demonstrate how the dynamics of tree stems and biomass vary between secondary and old‐growth forests with changes in the dominance of lianas and environmental gradients.Greater tree recruitment and mortality in secondary forests compared with old‐growth forests suggested rapid regeneration processes and faster turnover. However, no significant differences were found in the net annual changes in the number or biomass of trees between secondary and old‐growth forests.Our findings also showed that higher LTRs were positively associated with stem mortality but also with tree biomass growth, indicating a nuanced ecological role of lianas in forest ecosystems, which warrants further investigation to fully understand the causal factors at play.Net changes in tree stem numbers decreased significantly with elevation, implying climatic constraints on forest regeneration at higher elevations. Soil cation exchange capacity and organic carbon were found to significantly influence tree stem recruitment and net change in abundance, although their effects on biomass remained unclear.Synthesis: Our findings indicate that the recovery of tropical forests from disturbance in terms of the number and biomass of tree stems may be predictable along environmental gradients. These insights have the potential to broaden our capacity to develop more nuanced strategies that identify when and where tropical forests may require restoration interventions, with a focus on structural recovery. [ABSTRACT FROM AUTHOR]

Plant‐microbial‐herbivore interactions play a crucial role in the structuring and maintenance of plant communities and biodiversity, yet these relationships are complex. In grassland ecosystems, herbivores have the potential to greatly influence the survival, growth and reproduction of plants. However, few studies examine interactions of above‐ and below‐ground grazing and arbuscular mycorrhizal (AM) mycorrhizal symbiosis on plant community structure. We established experimental mesocosms containing an assemblage of eight tallgrass prairie grass and forb species in native prairie soil, maintained under mycorrhizal and nonmycorrhizal conditions, with and without native herbivorous soil nematodes, and with and without grasshopper herbivory. Using factorial analysis of variance and principal component analysis, we examined: (a) the independent and interacting effects of above‐ and below‐ground herbivores on AM symbiosis in tallgrass prairie mesocosms, (b) independent and interacting effects of above‐ and below‐ground herbivores and mycorrhizal fungi on plant community structure and (c) potential influences of mycorrhizal responsiveness of host plants on herbivory tolerance and concomitant shifts in plant community composition. Treatment effects were characterized by interactions between AM fungi and both above‐ground and below‐ground herbivores, while herbivore effects were additive. The dominance of mycorrhizal‐dependent C4 grasses in the presence of AM symbiosis was increased (p < 0.0001) by grasshopper herbivory but reduced (p < 0.0001) by nematode herbivory. Cool‐season C3 grasses exhibited a competitive release in the absence of AM symbiosis but this effect was largely reversed in the presence of grasshopper herbivory. Forbs showed species‐specific responses to both AM fungal inoculation and the addition of herbivores. Biomass of the grazing‐avoidant, facultatively mycotrophic forb Brickellia eupatorioides increased (p < 0.0001) in the absence of AM symbiosis and with grasshopper herbivory, while AM‐related increases in the above‐ground biomass of mycorrhizal‐dependent forbs Rudbeckia hirta and Salvia azurea were eradicated (p < 0.0001) by grasshopper herbivory. In contrast, nematode herbivory enhanced (p = 0.001) the contribution of Salvia azurea to total biomass. Synthesis. Our research indicates that arbuscular mycorrhizal symbiosis is the key driver of dominance of C4 grasses in the tallgrass prairie, with foliar and root herbivory being two mechanisms for maintenance of plant diversity. [ABSTRACT FROM AUTHOR]

The rhizosphere influence on the soil microbiome and function of crop wild progenitors (CWPs) remains virtually unknown, despite its relevance to develop microbiome‐oriented tools in sustainable agriculture. Here, we quantified the rhizosphere influence—a comparison between rhizosphere and bulk soil samples—on bacterial, fungal, protists and invertebrate communities and on soil multifunctionality across nine CWPs at their sites of origin. Overall, rhizosphere influence was higher for abundant taxa across the four microbial groups and had a positive influence on rhizosphere soil organic C and nutrient contents compared to bulk soils. The rhizosphere influence on abundant soil microbiomes was more important for soil multifunctionality than rare taxa and environmental conditions. Our results are a starting point towards the use of CWPs for rhizosphere engineering in modern crops. [ABSTRACT FROM AUTHOR]

The essential role of fertilization in the management of oil palm plantations cannot be overstated, with the understanding that effective strategies must be finetuned to accommodate the diversity of soil types present. The nuanced response of oil palm to fertilization under different soil conditions underscores the critical nature of this research. This study investigates the relationship between oil palm farming practices and agro-environmental performance of plantations. This research aims to understand the complex mechanisms influencing plantation productivity. Five agronomic field experiments were carried out on various soil types (Podzol, Inceptisol, Peat) during 2022. These experiments involved various types of soil and used different plant materials in a total land area of 33 hectares. The results of the peat soil trials revealed a positive effect of RP fertilizer on leaf phosphorus (P) content and a visible gradient in potassium (K) content with different doses of KCl. Average plantation yields peaked in 2022, showing the best yields ever recorded. On the contrary, experiments in podzolic soils showed that oil palm responded better to organic fertilizers than to mineral fertilizers in podzolic soils. The inceptisol soil revealed a significant increase in leaf potassium (K) content with KCl dose, confirming the positive effect of fresh oil palm empty fruit bunches (EFB) on potassium levels. In particular, EFB acts as a good K fertilizer, positively influencing the K content but negatively affecting the calcium content (Ca) due to K/Ca antagonism. These findings emphasize the need for diversified agricultural strategies to optimize oil palm cultivation, increase productivity, and reduce dependence on external input. [ABSTRACT FROM AUTHOR]

Aims: Plant functional group (PFG) removal experiments are recognized as an effective way to explore the role of plant diversity and species traits in ecosystem functioning. To minimize soil physical disturbance in plant removal experiments, aboveground parts of targeted plant species are usually cut off without removing their roots from the soil. However, the potential effects of their remaining roots (partially as root litter) on soil nematode communities are still unclear. Methods: We used a three-year PFG removal experiment in a Qinghai-Tibet alpine meadow and set up root-ingrowth mesh bags for one year where removal target plants' roots existed only outside the mesh bags. Results: We found that nematode communities outside the mesh bags had higher nematode channel ratio and lower channel index values, indicating that the root litter outside the mesh bags increased energy flux to bacterial-feeding nematodes over fungal-feeding nematodes. The relative abundance of plant-feeding nematodes was higher inside than outside the mesh bags, probably because of a higher ratio of living roots inside the mesh bags. Non-metric multidimensional scaling showed that the structure of nematode communities inside and outside of mesh bags was generally differentiated except for the no-removal control treatment. Conclusions: We conclude that the remaining roots outside mesh bags could modify the relative abundance ratio of different nematode guilds and soil nematode community structures, suggesting legacy effects of target plants' roots in PFG removal experiments. [ABSTRACT FROM AUTHOR]

Plant–soil biodiversity interactions are fundamental for the functioning of terrestrial ecosystems. Yet, the existence of a set of globally distributed topsoil microbial and small invertebrate organisms consistently associated with land plants (i.e., their consistent soil‐borne microbiome), together with the environmental preferences and functional capabilities of these organisms, remains unknown. We conducted a standardized field survey under 150 species of land plants, including 58 species of bryophytes and 92 of vascular plants, across 124 locations from all continents. We found that, despite the immense biodiversity of soil organisms, the land plants evaluated only shared a small fraction (less than 1%) of all microbial and invertebrate taxa that were present across contrasting climatic and soil conditions and vegetation types. These consistent taxa were dominated by generalist decomposers and phagotrophs and their presence was positively correlated with the abundance of functional genes linked to mineralization. Finally, we showed that crossing environmental thresholds in aridity (aridity index of 0.65, i.e., the transition from mesic to dry ecosystems), soil pH (5.5; i.e., the transition from acidic to strongly acidic soils), and carbon (less than 2%, the lower limit of fertile soils) can result in drastic disruptions in the associations between land plants and soil organisms, with potential implications for the delivery of soil ecosystem processes under ongoing global environmental change. [ABSTRACT FROM AUTHOR]

Janzen-Connell effects state that the accumulation of host-specific natural enemies near parent plants can negatively affect their offspring. Negative plant-soil feedbacks can produce patterns of seedling performance predicted by Janzen-Connell effects and influence plant populations, but their relevance in field conditions remains unclear. Here, using spatial point-pattern analysis, we examine the spatial distribution of Jacobaea vulgaris to assess whether distance- and density-dependent predictions of Janzen-Connell effects are evident in the field. We established 27 replicated 64 m2 plots at two grassland sites and mapped positions of rosette-bearing and flowering J. vulgaris plants within each plot. To investigate temporal distribution patterns, we tracked plant positions repeatedly in three plots during a single season. Additionally, we tested whether these patterns are soil-mediated. Soil samples were collected underneath flowering plants and at a distance of 0.5 meter, and used to compare seed germination, seedling survival, and growth under controlled conditions. Furthermore, we measured J. vulgaris growth in soil from patches with high J. vulgaris densities and in soil from areas outside these patches. The density of rosette-bearing plants was lower at close distances from flowering plants than expected from null models, suggesting negative distance-dependent plant recruitment. The degree of clustering decreased over time from rosette-bearing to flowering plants, indicating density-dependent self-thinning. Seed germination was higher in soil further away from flowering J. vulgaris plants than in soil underneath plants at one site, but soil distance was not an overall significant factor in explaining seed germination. However, seedling mortality and biomass did not differ between soils collected at the two distances, and plants produced similar biomass in soil collected from inside and outside J. vulgaris patches. Our study demonstrates conspecific distance- and density-dependent plant recruitment in J. vulgaris in the field, but we found no evidence this depends on belowground natural enemies. [ABSTRACT FROM AUTHOR]

BACKGROUND AND AIMS: Our understanding of plant responses to biotic and abiotic drivers is largely based on above-ground plant traits, with little focus on below-ground traits despite their key role in water and nutrient uptake. Here, we aimed to understand the extent to which above- and below-ground traits are co-ordinated, and how these traits respond to soil moisture gradients and plant intraspecific competition. METHODS: We chose seedlings of five tropical tree species and grew them in a greenhouse for 16 weeks under a soil moisture gradient [low (drought), medium and high (well-watered) moisture levels] with and without intraspecific competition. At harvest, we measured nine above- and five below-ground traits of all seedlings based on standard protocols. KEY RESULTS: In response to the soil moisture gradient, above-ground traits are found to be consistent with the leaf economics spectrum, whereas below-ground traits are inconsistent with the root economics spectrum. We found high specific leaf area and total leaf area in well-watered conditions, while high leaf dry matter content, leaf thickness and stem dry matter content were observed in drought conditions. However, below-ground traits showed contrasting patterns, with high specific root length but low root branching index in the low water treatment. The correlations between above- and below-ground traits across the soil moisture gradient were variable, i.e. specific leaf area was positively correlated with specific root length, while it was negatively correlated with root average diameter across moisture levels. However, leaf dry matter content was unexpectedly positively correlated with both specific root length and root branching index. Intraspecific competition has influenced both above- and below-ground traits, but interacted with soil moisture to affect only below-ground traits. Consistent with functional equilibrium theory, more biomass was allocated to roots under drought conditions, and to leaves under sufficient soil moisture conditions. CONCLUSIONS: Our results indicate that the response of below-ground traits to plant intraspecific competition and soil moisture conditions may not be inferred using above-ground traits, suggesting that multiple resource use axes are needed to understand plant ecological strategies. Lack of consistent leaf-root trait correlations across the soil moisture gradient highlight the multidimensionality of plant trait relationships which needs more exploration.

This study investigated soil fungal biodiversity in wheat-based crop rotation systems on Chernozem soil within the Pannonian Basin, focusing on the effects of tillage, crop rotation, and soil properties. Over three years, soil samples from ten plots were analyzed, revealing significant fungal diversity with Shannon–Wiener diversity indices ranging from 1.90 in monoculture systems to 2.38 in a fertilized two-year crop rotation. Dominant fungi, including Fusarium oxysporum, Penicillium sp., and Aspergillus sp., showed distinct preferences for soil conditions such as pH and organic matter (OM). Conservation tillage significantly enhanced fungal diversity and richness, with the highest diversity observed in a three-year crop rotation system incorporating cover crops, which achieved an average winter wheat yield of 7.0 t ha−1—47% higher than unfertilized monoculture systems. Increased OM and nitrogen levels in these systems correlated with greater fungal abundance and diversity. Canonical correspondence analysis revealed strong relationships between fungal communities and soil properties, particularly pH and calcium carbonate content. These findings highlight the importance of tailored crop rotation and tillage strategies to improve soil health, enhance microbial biodiversity, and boost agricultural sustainability in temperate climates, providing valuable insights for mitigating the impacts of intensive farming and climate change.

Plant roots employ diverse strategies to acquire soil nutrients, including direct nutrient uptake through absorptive fine roots and root hairs, scavenging nutrients by forming symbioses with mycorrhizal fungi, and mining nutrients by releasing root exudates. However, whether these three strategies are differently coordinated among phylogenetically closely related tree species and how this coordination shifts with stand development remains largely unclear.To fill these knowledge gaps, we measured 13 root morphological, architectural, physiological and mycorrhizal traits tightly related to nutrient‐acquisition of three Pinus species (P. sylvestris var. mongolica, P. densiflora and P. tabuliformis) at young (20‐year‐old) and mature (50‐year‐old) stages planted in nutrient‐impoverished sandy soils, in Northeast China.We found that young trees had thinner absorptive fine roots and a higher specific root length than mature trees across three Pinus species, indicating that roots become morphologically less efficient in 'do it yourself' scavenging nutrients during stand development. Moreover, young stands had greater root length density and root area index, and mature stands had faster root‐exudation rates, suggesting that young stands rely more on expanding soil volumes to scavenge nutrients and mature stands depend more on root exudation to 'mine' nutrients. The three Pinus species exhibited different nutrient‐acquisition strategies at the mature stage; P. densiflora had higher root length density and root area index, and the other two Pinus species had greater ectomycorrhizal colonization rates.Synthesis. Our findings highlight that phylogenetically closely related tree species may exhibit different nutrient‐acquisition strategies and suggest a shift from an extensive nutrient‐acquisition mode depending more on absorptive fine roots to an intensive nutrient‐acquisition mode relying more on root exudation during stand development. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal (AM) fungi frequently colonise plant roots and can affect plant morphology and physiology through their contribution to plant nutrition. However, the functional role of AM fungi in the presence of other microbial symbionts, including widespread Mucoromycotina 'fine root endophytes' (MFRE) fungi, remains largely unknown.While both AM fungi and MFRE transfer nutrients, including nitrogen, from inorganic and organic sources to host plants, their combined effects on co‐colonised plants have only been investigated in liverworts. Here, we compare the morphology and physiology of the grass Holcus lanatus grown with an AM fungal community versus a more diverse symbiotic fungal community containing both AM fungi and MFRE.Holcus lanatus plants were grown in the presence of either a diverse MFRE+AM fungi soil inoculum or a multi‐species AM fungal inoculum. Plant traits associated with growth were quantified, along with fungal transfer of 15N tracer to plants from a variety of sources (ammonium chloride, alanine, glycine and algal necromass).Holcus lanatus grown with the AM fungal community had greater root and shoot growth during early development and prior to the addition of 15N‐labelled sources, compared with plants grown with the more diverse symbiotic fungal community. When nitrogen sources were made available to the fungal symbionts in the pot microcosms, plants growing with the MFRE+AM fungi soil inoculum had a faster growth rate than plants growing with the AM fungal community. At harvest, H. lanatus grown with the AM fungal community had a larger biomass, and there were no differences in 15N tracer assimilation in plants across the two fungal community treatments.Our results demonstrate that the diversity of fungal inocula in conjunction with soil nutrient availability determine the benefits derived by plants from diverse fungal symbionts. Our research contributes to understanding host plant outcomes in diverse multi‐symbiont scenarios. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Summary: We discuss which plant species are likely to become winners, that is achieve the highest global abundance, in changing landscapes, and whether plant‐associated microbes play a determining role. Reduction and fragmentation of natural habitats in historic landscapes have led to the emergence of patchy, hybrid landscapes, and novel landscapes where anthropogenic ecosystems prevail. In patchy landscapes, species with broad niches are favoured. Plasticity in the degree of association with symbiotic microbes may contribute to broader plant niches and optimization of symbiosis costs and benefits, by downregulating symbiosis when it is unnecessary and upregulating it when it is beneficial. Plasticity can also be expressed as the switch from one type of mutualism to another, for example from nutritive to defensive mutualism with increasing soil fertility and the associated increase in parasite load. Upon dispersal, wide mutualistic partner receptivity is another facet of symbiont plasticity that becomes beneficial, because plants are not limited by the availability of specialist partners when arriving at new locations. Thus, under conditions of global change, symbiont plasticity allows plants to optimize the activity of mutualistic relationships, potentially allowing them to become winners by maximizing geographic occupancy and local abundance. [ABSTRACT FROM AUTHOR]

This study investigated the soil physicochemical properties and vegetation community characteristics of the Baotou light rare earth tailings pond after 10 years of aggregate spray seeding ecological restoration (S1) and ordinary soil spray seeding ecological restoration (S2), and the naturally restored dam slope area without human intervention (S3). The results showed that the vegetation community of S1 was dominated by Caragana korshinskii Kom, and its importance and abundance values were 0.40 and 38.4, respectively, while the vegetation communities of S2 and S3 mainly comprised herbaceous plants. Additionally, the vegetation biomass of S1 was significantly higher than that of S2 and S3 by 215.20% and 1345.76%, respectively, and the vegetation diversity index of S1 was the highest among the three treatment groups. The soil porosity (SP), water content (W), electrical conductivity (EC), and available K were significantly improved in S1, while soil bulk density (BD) was significantly reduced compared with that of S2 and S3. In addition, redundancy analysis revealed that SP, EC, W, and K positively correlate with the biomass, Shannon, Pielou, Simpson, and Marglef indices. Principal component analysis further showed that the comprehensive score of S1 (0.983) was higher than that of S2 (− 0.261) and S3 (− 0.648). Collectively, these findings indicate that appropriate ecological restoration can improve soil structure and vegetation community characteristics, thereby accelerating vegetation restoration, ultimately increasing the stability of the ecosystem. [ABSTRACT FROM AUTHOR]

Low available soil nitrogen (N) limits plant productivity in alpine regions, and alpine plants thus resorb and reallocate N from senescing tissues to conserve this limited N during the non‐growing season. However, the destination and extent of N redistribution during plant senescence among above‐ and below‐ground organs, let alone other processes of translocation outside of plants and into the soil components, remain poorly understood.Utilizing 15N stable isotope as a tracer, we quantified N redistribution among above‐ and below‐ground plant organs and different soil components during senescence in an alpine meadow ecosystem, and explored the relationship between 15N partitioning among plant–soil N pools with seasonal fluctuations of plant functional traits.We found a substantial depletion of 15N in fine roots (−40% ± 2.8%) and above‐ground tissues (−51% ± 5.1%), and an enhanced 15N retention primarily in coarse roots (+79% ± 27%) and soil organic matter (+37% ± 10%) during plant senescence, indicating a dual role of roots with coarse roots acting as an N sink and fine roots as a source of N recycling during senescence. In parallel, we observed a temporal variation in plant functional traits, representing a shift from more acquisitive to more conservative strategies as the growing season ends, such as higher coarse root N and coarse root to fine root ratio. The seasonal trait variations were highly correlated with the 15N retention in coarse roots and soil organic matter. Particularly, 15N retention in particulate and mineral‐associated organic matter increased by 30% ± 12% and 24% ± 9%, respectively, suggesting a potential pathway through which fine root and microbial mortality contribute to 15N redistribution into soil N pools during senescence.Synthesis. N redistribution and seasonal plant trait fluctuation facilitate plant N conservation and ecosystem N retention in the alpine system. This study suggests a coupled above‐ground‐below‐ground N conservation strategy that may optimize the temporal coupling between plant N demand and ecosystem N supply in N‐limited alpine ecosystems. [ABSTRACT FROM AUTHOR]

The seasonal coupling of plant and soil microbial nutrient demands is crucial for efficient ecosystem nutrient cycling and plant production, especially in strongly seasonal alpine ecosystems. Yet, how these seasonal nutrient cycling processes are modified by climate change and what the consequences are for nutrient loss and retention in alpine ecosystems remain unclear. Here, we explored how two pervasive climate change factors, reduced snow cover and shrub expansion, interactively modify the seasonal coupling of plant and soil microbial nitrogen (N) cycling in alpine grasslands, which are warming at double the rate of the global average. We found that the combination of reduced snow cover and shrub expansion disrupted the seasonal coupling of plant and soil N‐cycling, with pronounced effects in spring (shortly after snow melt) and autumn (at the onset of plant senescence). In combination, both climate change factors decreased plant organic N‐uptake by 70% and 82%, soil microbial biomass N by 19% and 38% and increased soil denitrifier abundances by 253% and 136% in spring and autumn, respectively. Shrub expansion also individually modified the seasonality of soil microbial community composition and stoichiometry towards more N‐limited conditions and slower nutrient cycling in spring and autumn. In winter, snow removal markedly reduced the fungal:bacterial biomass ratio, soil N pools and shifted bacterial community composition. Taken together, our findings suggest that interactions between climate change factors can disrupt the temporal coupling of plant and soil microbial N‐cycling processes in alpine grasslands. This could diminish the capacity of these globally widespread alpine ecosystems to retain N and support plant productivity under future climate change. [ABSTRACT FROM AUTHOR]

Premise: Intraspecific variation may play a key role in shaping the relationships between plants and their interactions with soil microbial communities. The soil microbes of individual plants can generate intraspecific variation in the responsiveness of the plant offspring, yet have been much less studied. To address this need, we explored how the relatedness of seedlings from established clones of Solidago altissima altered the plant–soil interactions of the seedlings. Methods: Seedlings of known parentage were generated from a series of 24 clones grown in a common garden. Seedlings from these crosses were inoculated with soils from maternal, paternal, or unrelated clones and their performance compared to sterilized control inocula. Results: We found that soil inocula influenced by S. altissima clones had an overall negative effect on seedling biomass. Furthermore, seedlings inoculated with maternal or paternal soils tended to experience larger negative effects than seedlings inoculated with unrelated soils. However, there was much variation among individual crosses, with not all responding to relatedness. Conclusions: Our data argue that genetic relatedness to the plant from which the soil microbial inoculum was obtained may cause differential impacts on establishing seedlings, encouraging the regeneration of non‐kin adjacent to established clones. Such intraspecific variation represents a potentially important source of heterogeneity in plant–soil microbe interactions with implications for maintaining population genetic diversity. [ABSTRACT FROM AUTHOR]

Agricultural soils contaminated with heavy metals (HMs) impose a threat to the environmental and to human health. Amendment with biochar could be an eco-friendly and cost-effective option to decrease HMs in contaminated soil. This paper reviews the application of biochar as a soil amendment to immobilise HMs in contaminated soil. We discuss the technologies of its preparation, their specific properties, and effect on the bioavailability of HMs. Biochar stabilises HMs in contaminated soil, enhance the overall quality of the contaminated soil, and significantly reduce HM uptake by plants, making it an option in soil remediation for HM contamination. Biochar enhances the physical (e.g. bulk density, soil structure, water holding capacity), chemical (e.g. cation exchange capacity, pH, nutrient availability, ion exchange, complexes), and biological properties (e.g. microbial abundance, enzymatic activities) of contaminated soil. Biochar also enhances soil fertility, improves plant growth, and reduces the plant availability of HMs. Various field studies have shown that biochar application reduces the bioavailability of HMs from contaminated soil while increasing crop yield. The review highlights the positive effects of biochar by reducing HM bioavailability in contaminated soils. Future work is recommended to ensure that biochars offer a safe and sustainable solution to remediate soils contaminated with HMs. [ABSTRACT FROM AUTHOR]

Societal Impact Statement Climate‐change and land‐use intensification are degrading ecosystems globally, impeding their services to humans (e.g., food security and human health). The United Nations 13th and 15th Sustainable Development Goals (SDGs) call for action to protect and restore ecosystems. Only transdisciplinary research can unravel the multitudes of interacting ecosystem parts that could help accomplish these SDGs. However, a major challenge will be overcoming material, social and other types of barriers that prevent collaborations. This study explores some of these challenges and seeks the views of the community through a survey to help develop a new age of plant science collaboration. Summary In this opinion article, we explore the problem of missed opportunities for collaboration in fields related to plant science. Lack of awareness of the scientific output, which can be gained from transdisciplinary collaborations, as well as the opportunities they can provide for early‐career scientists, may contribute to this. Here, we name communication barriers as particularly inhibitory to the formation of collaborations and propose possible solutions to overcome these barriers. Eventual action towards these solutions needs to be based on the opinions of the community. We thus intend this article to initiate a dialogue among researchers across the many disciplines of plant science about the feasibility of these proposed solutions. The questionnaire included with this article, intended for the broad plant research community, we believe could help us gain the necessary information to proceed in addressing communication barriers to transdisciplinary science collaborations. We provide a theoretical framework, examples and timely topics as discussion points to inspire participants of the questionnaire to contribute their voice to shaping a new age of plant science collaboration.

Microbiomes play critical roles in host functioning and, therefore, there is increasing interest in the microbiome assembly of plants. However, sampling strategies for long-lived perennial trees need to be standardized to produce robust data that accurately represent the microbiome over time. This issue is currently unresolved because there is little evidence indicating which portion of perennial tree species (e.g., root region or surrounding soil) is the best to sample to produce the most accurate measure of microbiome communities. Our aim was to sample different compartments of a plant's belowground microbiome to identify the optimal sampling strategy to account for the microbial community present. We found that the structure of the microbial community depends most strongly on the environment (site) and compartment of sample collected (bulk soil, rhizosphere, or rhizoplane), rather than the depth or cardinal direction of the sample. We also found that the microbial community increased in diversity with increased distance from the tree within the rhizoplane and rhizosphere. The data presented here provide systematic evidence for a pragmatic and robust sampling regime that was tested and validated across different environments and soil types while controlling for host genotype. This sampling regime will enable effective partitioning of root compartments when studying the microbiome associated with perennial tree species, allowing targeted questions about the microbiome to be explored with greater accuracy.

Plant nutrient uptake and productivity are driven by a multitude of factors that have been modified by human activities, like climate change and the activity of decomposers. However, interactive effects of climate change and key decomposer groups like earthworms have rarely been studied. In a field microcosm experiment, we investigated the effects of a mean future climate scenario with warming (+ 0.50 °C to + 0.62 °C) and altered precipitation (+ 10% in spring and autumn, − 20% in summer) and earthworms (anecic—two Lumbricus terrestris, endogeic—four Allolobophora chlorotica and both together within 10 cm diameter tubes) on plant biomass and stoichiometry in two land-use types (intensively used meadow and conventional farming). We found little evidence for earthworm effects on aboveground biomass. However, future climate increased above- (+40.9%) and belowground biomass (+44.7%) of grass communities, which was mainly driven by production of the dominant Festulolium species during non-summer drought periods, but decreased the aboveground biomass (− 36.9%) of winter wheat. Projected climate change and earthworms interactively affected the N content and C:N ratio of grasses. Earthworms enhanced the N content (+1.2%) thereby decreasing the C:N ratio (− 4.1%) in grasses, but only under ambient climate conditions. The future climate treatment generally decreased the N content of grasses (aboveground: − 1.1%, belowground: − 0.15%) and winter wheat (− 0.14%), resulting in an increase in C:N ratio of grasses (aboveground: + 4.2%, belowground: +6.3%) and wheat (+5.9%). Our results suggest that climate change diminishes the positive effects of earthworms on plant nutrient uptakes due to soil water deficit, especially during summer drought. [ABSTRACT FROM AUTHOR]

Precipitation changes modify C, N, and P cycles, which regulate the functions and structure of terrestrial ecosystems. Although altered precipitation affects above‐ and belowground C:N:P stoichiometry, considerable uncertainties remain regarding plant–microbial nutrient allocation strategies under increased (IPPT) and decreased (DPPT) precipitation. We meta‐analyzed 827 observations from 235 field studies to investigate the effects of IPPT and DPPT on the C:N:P stoichiometry of plants, soils, and microorganisms. DPPT reduced leaf C:N ratio, but increased the leaf and root N:P ratios reflecting stronger decrease of P compared with N mobility in soil under drought. IPPT increased microbial biomass C (+13%), N (+15%), P (26%), and the C:N ratio, whereas DPPT decreased microbial biomass N (−12%) and the N:P ratio. The C:N and N:P ratios of plant leaves were more sensitive to medium DPPT than to IPPT because drought increased plant N content, particularly in humid areas. The responses of plant and soil C:N:P stoichiometry to altered precipitation did not fit the double asymmetry model with a positive asymmetry under IPPT and a negative asymmetry under extreme DPPT. Soil microorganisms were more sensitive to IPPT than to DPPT, but they were more sensitive to extreme DPPT than extreme IPPT, consistent with the double asymmetry model. Soil microorganisms maintained stoichiometric homeostasis, whereas N:P ratios of plants follow that of the soils under altered precipitation. In conclusion, specific N allocation strategies of plants and microbial communities as well as N and P availability in soil critically mediate C:N:P stoichiometry by altered precipitation that need to be considered by prediction of ecosystem functions and C cycling under future climate change scenarios. [ABSTRACT FROM AUTHOR]

Root functional traits are known to influence soil properties that underpin ecosystem functioning. Yet few studies have explored how root traits simultaneously influence physical, chemical, and biological properties of soil, or how these responses are modified by common grassland perturbations that shape roots, such as defoliation and fertilisation.Here, we explored how root traits of a wide range of grassland plant species with contrasting resource acquisition strategies (i.e. conservative vs. exploitative strategy plant species) respond to defoliation and fertilisation individually and in combination, and examined cascading impacts on a range of soil abiotic and biotic properties that underpin ecosystem functioning.We found that the amplitude of the response of root traits to defoliation and fertilisation varied among plant species, in most cases independently of plant resource acquisition strategies. However, the direction of the root trait responses (increase or decrease) to perturbations was consistent across all plant species, with defoliation and fertilisation exerting opposing effects on root traits. Specific root length increased relative to non‐perturbed control in response to defoliation, while root biomass, root mass density, and root length density decreased. Fertilisation induced the opposite responses. We also found that both defoliation and fertilisation individually enhanced the role of root traits in regulating soil biotic and abiotic properties, especially soil aggregate stability.Synthesis: Our results indicate that defoliation and fertilisation, two common grassland perturbations, have contrasting impacts on root traits of grassland plant species, with direct and indirect short‐term consequences for a wide range of soil abiotic and biotic properties that underpin ecosystem functioning. [ABSTRACT FROM AUTHOR]

Animals interact with and impact ecosystem biogeochemical cycling—processes known as zoogeochemistry. While the deposition of various animal materials (e.g. carcasses and faeces) has been shown to create nutrient hotspots and alter nutrient cycling and storage, the inputs from parturition (i.e. calving) have yet to be explored. We examine the effects of ungulate parturition, which often occurs synchronously during spring green‐up and therefore aligns with increased plant nitrogen demand in temperate biomes.Impacts of zoogeochemical inputs are likely context‐dependent, where differences in material quality, quantity and the system of deposition modulate their impacts. Plant mycorrhizal associations, especially, create different nutrient‐availability contexts, which can modify the effects of nutrient inputs. We, therefore, hypothesize that mycorrhizal associations modulate the consequences of parturition on soil nutrient dynamics and nitrogen pools.We established experimental plots that explore the potential of two kinds of zoogeochemical inputs deposited at ungulate parturition (placenta and natal fluid) in forest microsites dominated by either ericoid mycorrhizal (ErM) or ectomycorrhizal (EcM) plants. We assess how these inputs affect rates of nutrient cycling and nitrogen content in various ecosystem pools, using isotope tracers to track the fate of nitrogen inputs into plant and soil pools.Parturition treatments accelerate nutrient cycling processes and increase nitrogen contents in the plant leaf, stem and fine root pools. The ecosystem context strongly modulates these effects. Microsites dominated by ErM plants mute parturition treatment impacts on most nutrient cycling processes and plant pools. Both plant–fungal associations are, however, equally efficient at retaining nitrogen, although retention of nitrogen in the parturition treatment plots was more than two times lower than in control plots.Our results highlight the potential importance of previously unexamined nitrogen inputs from animal inputs, such as those from parturition, in contributing to fine‐scale heterogeneity in nutrient cycling and availability. Animal inputs should therefore be considered, along with their interactions with plant mycorrhizal associations, in terms of how zoogeochemical dynamics collectively affect nutrient heterogeneity in ecosystems. [ABSTRACT FROM AUTHOR]

Nitrogen (N)‐fixing trees are thought to break a basic rule of leaf economics: higher leaf N concentrations do not translate into higher rates of carbon assimilation. Understanding how leaf N affects photosynthesis and water use efficiency (WUE) in this ecologically important group is critical.We grew six N‐fixing and four non‐fixing tree species for 4–5 years at four fertilization treatments in field experiments in temperate and tropical regions to assess how functional type (N fixer vs. non‐fixer) and N limitation affected leaf N and how leaf N affected light‐saturated photosynthesis (Asat), stomatal conductance (gsw) and WUE (WUEi and δ13C).Asat, WUEi and δ13C, but not gsw, increased with higher leaf N. Surprisingly, N‐fixing and non‐fixing trees displayed similar scaling between leaf N and these physiological variables, and this finding was supported by reanalysis of a global dataset. N fixers generally had higher leaf N than non‐fixers, even when non‐fixers were not N‐limited at the leaf level. Leaf‐level N limitation did not alter the relationship of Asat, gsw, WUEi and δ13C with leaf N, although it did affect the photosynthetic N use efficiency. Higher WUE was associated with higher productivity, whereas higher Asat was not.Synthesis: The ecological success of N‐fixing trees depends on the effect of leaf N on carbon gain and water loss. Using a field fertilization experiment and reanalysis of a global dataset, we show that high leaf‐level photosynthesis and WUE in N fixers stems from their higher average leaf N, rather than a difference between N fixers and non‐fixers in the scaling of photosynthesis and WUE with leaf N. By clarifying the mechanism by which N fixers achieve and benefit from high WUE, our results further the understanding of global N fixer distributions. [ABSTRACT FROM AUTHOR]

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Biogas slurry (BS) is an attractive agricultural waste resource which can be used to regulate soil microbial communities, enhance nutrient absorption capacity of crops, promote plant–soil interactions, and consequently, increase crop productivity. Presently, BS discharge is not environmentally friendly. It is therefore necessary to explore alternative efficient utilization of BS. The use of BS as fertilizer meets the requirements for sustainable and eco-friendly development in agriculture, but this has not been fully actualized. Hence, this paper reviewed the advantages of using BS in farmland as soil fertilization for the improvement of crop production and quality. This review also highlighted the potential of BS for the prevention and control of soil acidification, salinization, as well as improve microbial structure and soil enzyme activity. Moreover, this review reports on the current techniques, application methods, relevant engineering measures, environmental benefits, challenges, and prospects associated with BS utilization. Lastly, additional research efforts require for optimal utilization of BS in farmlands were elucidated. [ABSTRACT FROM AUTHOR]