Soil Functional Diversity Research Articles

Imprints of Soil Microbial Activity Accredited to Residue-Management and Tillage Practices for Boosting Rice and Wheat Production

The sustainable productivity of rice–wheat cropping systems relies on soil health, and soil health can be positively influenced by treating previous crop residues using conservation tillage practices. The present study examined the impact of three rice residue-management practices under zero-tilled wheat (ZTW) and conventionally tilled wheat (CTW), along with two rice-sowing practices, during rice cultivation on soil functional microbial diversity, physiological profiling, and grain yields of rice and wheat. Anchored residues (ARs) under ZTW exhibited significantly (p ≤ 0.05) high average well color development—31.43% more than CTW with no residue (NR). CTW with residue burning (BUR) showed a 5.42% increase in the Shannon diversity index compared to CTW-NR. Substrate richness was 10.02% higher in CTW-BUR compared to CTW-NR. CTW-BUR demonstrated the highest 17.98% increase in the Shannon evenness index compared to CTW-NR. The direct-seeded rice (DSR) system generally surpassed puddled transplanted rice (PTR) in most indices, except for the Shannon evenness index values. ZTW-AR exhibited the highest utilization of amino acids, carboxylic acids, and phenolic compounds, while CTW-BUR exhibited the highest utilization of carbohydrates and polymers utilization, and ZTW with no-residue (NR) exhibited the highest utilization of amines. Rice and wheat grain yields were highest with full residue in ZTW and lowest in CTW-NR. PTR supported higher rice yields, while DSR was superior for wheat. These findings highlight the favorable role of residue retention with no tillage during wheat cultivation in the maintenance of soil quality and rice–wheat productivity.

Unveiling the Impact of Soil Prebiotics on Rhizospheric Microbial Functionality in Zea mays L.

Prebiotics, a subset of biostimulants, have garnered attention for their potential to enhance soil conditions and promote plant growth, offering a promising alternative to conventional agricultural inputs. This study explores how two commercial prebiotics, K1® and NUTRIGEO L® (SPK and SPN), impact soil functions compared to a control (SP). The experiment involved agricultural soil amended with organic wheat straws and cultivated with Zea mays L. Previous research demonstrated substantial effects of these prebiotics on plant biomass, soil parameters, and microbial community ten weeks after application. The present study delves deeper, focusing on soil microbial abundance, enzyme activities, and metabolic diversity. Analysis revealed that SPN notably increased the fungi-to-bacteria ratio, and both prebiotics elevated the activity of several key enzymes. SPN enhanced α-glucosidase and β-galactosidase activities, while SPK increased arylsulfatase, phosphatase, alkaline phosphatase, and urease activities. Enzymatic indexes confirmed the positive impact on soil functional diversity and fertility. Additionally, prebiotic treatments showed distinct metabolic profiles, with SPK degrading eleven carbon sources more rapidly across five groups and SPN accelerating the decomposition rate of four carbon sources from three groups. These findings highlight the ability of prebiotics to shape microbial communities and enhance soil fertility by modulating their functional activity and diversity.

The impact of reclamation and vegetation removal on compositional and functional attributes of soil microbial communities in the Athabasca Oil Sands Region

Large-scale mining for oil extraction in the boreal forests of Northern Alberta has led to a disturbance footprint of ~900 km2 of land; which must be reclaimed to equivalent land capabilities. Microorganisms are sensitive to anthropogenic disturbances and play an essential role in the cycling of soil nutrients and plant growth, making them potential indicators of ecosystem function. Thus, the objective of this work was to determine the impact of land reclamation on the composition and function of soil microbial communities in the Athabasca Oil Sands Region (AOSR). We evaluated bacterial community composition via high throughput sequencing of 16S rRNA genes and soil functional diversity by community-level physiological profiling (CLPP). The ranges of variability for these factors observed in soils reclaimed with either peat-mineral mix (PMM), forest floor-mineral mix (FFM), or FFM diluted with sand (Sand-FFM), were compared to that of undisturbed reference soils (NS) and a vegetation removed soil (VR). Differences between reclamation soils and natural soils were clearly discernible, with reclamation imposing a more drastic disturbance to the boreal forest than that of removal of vegetation alone. VR changed the structure of the soil microbial community and increased the overall diversity, within-community interactions, and heterogeneity; while reclamation shifted the microbial community structure to an even greater extent, placing it outside the range of natural variability. Among reclamation substrates, FFM showed the highest level of similarity to the range of natural variability and PMM showed the least. Altogether, our findings underscore the profound impact of anthropogenic activities associated with large-scale mining on soil biological activity, microbial communities, and edaphic profiles. These alterations are of such magnitude that they render the affected soils significant divergent from the reference undisturbed boreal forest soil.

Evaluation of Soil Total Nitrogen as an Indicator of Soil Bacterial Community Response to Biochar and Plant Growth-Promoting Rhizobacteria Applications

Biochar and plant growth-promoting rhizobacteria (PGPR) are widely used as an amendment for soil physicochemical properties and soil bacterial community diversity. In Guangxi, China, we carried out a study to determine how PGPR and biochar influence the soil’s environmental stability in an Eucalypt plantation. We applied biochar and PGPR in a contrasting application manner to an acidic red loam soil. Thus, three treatments were set up as 5 × 1010 CFU·mL−1 PGPR-only (MB0), 20 t·hm−2 biochar-only (B20), and co-application of 20 t·hm−2 biochar and 5 × 1010 CFU·mL−1 PGPR (MB20), as well as no biochar and no PGPR (M0B0). Our results indicated that MB20 significantly decreased the soil total nitrogen (TN) and increased the soil total phosphorus (Soil TP), soil ammonium nitrogen (NH4+), and soil water content (SWC) when compared with the control. The MB20 also significantly increased the Simpson, ACE, and Chao indices of the soil bacterial community’s diversity relative to the control. We also observed a significant effect of the Soil TN on both the bacterial community and the functional diversity in soil. These findings may indicate that assessing the soil N status is expected to be an essential indicator of the soil microenvironment’s response to biochar and PGPR applications.

More than a meat- or synthetic nitrogen fertiliser-substitute: a review of legume phytochemicals as drivers of 'One Health' via their influence on the functional diversity of soil- and gut-microbes.

Legumes are essential to healthy agroecosystems, with a rich phytochemical content that impacts overall human and animal well-being and environmental sustainability. While these phytochemicals can have both positive and negative effects, legumes have traditionally been bred to produce genotypes with lower levels of certain plant phytochemicals, specifically those commonly termed as 'antifeedants' including phenolic compounds, saponins, alkaloids, tannins, and raffinose family oligosaccharides (RFOs). However, when incorporated into a balanced diet, such legume phytochemicals can offer health benefits for both humans and animals. They can positively influence the human gut microbiome by promoting the growth of beneficial bacteria, contributing to gut health, and demonstrating anti-inflammatory and antioxidant properties. Beyond their nutritional value, legume phytochemicals also play a vital role in soil health. The phytochemical containing residues from their shoots and roots usually remain in-field to positively affect soil nutrient status and microbiome diversity, so enhancing soil functions and benefiting performance and yield of following crops. This review explores the role of legume phytochemicals from a 'one health' perspective, examining their on soil- and gut-microbial ecology, bridging the gap between human nutrition and agroecological science.

Influence of habitat fragmentation and habitat amount on soil fungi communities in ancient forests

ContextFungi represent a large part of soil biodiversity as well as an essential role for tree hydromineral nutrition, survival, and carbon cycling. While their local diversity has proven to be shaped by abiotic and biotic factors related to soil, climate and vegetation, their response to landscape fragmentation is still debated.ObjectivesIn this paper, we focus on ancient forests characterized by the presence of beech at low elevation, a habitat particularly fragmented in South-West France. We aim to assess the effect of past and present forest fragmentation and quantity on soil fungal and functional group diversity. We expect a negative impact of fragmentation and a positive effect of forest quantity on soil fungal diversity, in addition to an influence of local soil factors.MethodsSoils from 41 1ha ancient forest plots across South-West France were sampled along gradients of past and present forest fragmentation and quantity, before their fungal diversity was characterized by metabarcoding of environmental DNA. Hill numbers have been computed and applied to all fungi, trophic guilds and growth forms.ResultsWe find that past forest fragmentation negatively impacts on soil fungal diversity and in particular for symbiotrophs, while the present forest quantity has a positive impact. In contrast, the species richness of pathotrophic fungi shows a negative correlation with past forest fragmentation. The diversity of fungal groups with lower dispersal abilities (e.g., corticioid, microfungi) is negatively impacted by past forest fragmentation, while the diversity of wind-dispersed fungi (e.g., agaricoid) is not influenced by any landscape descriptors.ConclusionsOur results show the complexity of fungal responses to past and present forest fragmentation and demonstrate the long-lasting effect of past fragmentation as well as the positive impact of recent forest quantity in the landscape on fungal diversity associated with ancient forest soils. Our study also highlights the huge diversity of fungi unraveled by eDNA metabarcoding in this habitat and the potential of such techniques to study the landscape ecology of soil communities.

Effects of Different Planting Years on Soil Physicochemical Indexes, Microbial Functional Diversity and Fruit Quality of Pear Trees

This study explores the interaction between pear fruit quality and the soil environment over four different planting years (5, 20, 30, and 40 years), focusing on the fruit’s chemical properties, rhizosphere soil properties, microbial communities, and both microbiomass and functional diversity. The results found that reducing sugar, sucrose, and vitamin C contents in pears initially increased with planting years before declining, while total acidity showed an inverse trend. Analysis of the soil physicochemical index revealed that rhizosphere soil physicochemical indexes were significantly different between different planting years, but there was no obvious regularity. Correlation analysis found that total phosphorus, total potassium, organic matter, and available nitrogen were significantly and positively correlated with pear quality indexes. Soil microbiomass carbon decreased before increasing with increasing planting year, while soil microbial nitrogen was irregular. Results of functional diversity of rhizosphere soil bacterial communities showed that the relationship of carbon source utilization among the six groups was 20 years > 5 years > 30 years > 40 years. Interestingly, the 20-year group had the most core differences in microbial communities. The study suggests that as pear trees age, adequate plant nutrition during peak fruiting periods can improve soil fertility, microbial functional diversity, and ultimately enhance fruit quality.

Does forest stand density affect soil microbial communities?

Forest management aims to maintain sustainable production of quality wood while limiting increased competition between trees for light, water, and nutrients. Thinning is a widely used silvicultural practice to reduce plants competition for resources while still exploiting the wood. The investigation of the effects of forest management on stand functioning typically centers on the above-ground compartment, overlooking the alterations and influences exerted on below-ground biotic factors. Within the soil matrix, biological mechanisms are mainly governed by microbial communities. Many studies have focused on the effects of thinning on soil microbial communities (SMC), evidencing contrasted effects. Conversely, stand density effects on SMC are less documented. The aim of this study is therefore to focus on the effects of stand density (SD) on SMC biomass, gene abundance, functional diversity, and activity, according two sylvicultural practices: dynamic (low SD) and conservative (medium SD) in a temperate Quercus petraea Stand (QS) in Europe Forest. We hypothesized that dynamic silviculture (low-SD) could promote soil SMC biomass, abundance, functional diversity, and activity. Our results showed that dynamic silvicultural practices in oak forests reduced the abundances of bacteria, archaea and fungi were reduced by 43 %, 29 % and 34 %, respectively. SMC functional diversity was reduced by 10 % in dynamic forestry stands. On the contrary, dynamic silvicultural practices increased soil microbial activity by 13 to 47 %, depending on the carbon source added, compared with conservative silviculture. Our results were incremented with an extensive number of biotic and abiotic environmental variables that had contrasting effects on SMC, and there is no single factor, which alone can explain all the SMC responses. Our results seem to advocate dynamic silvicultural practices in oak forests to promote soil microbial activity. However, it remains to be seen what the long-term effects will be of the reduced abundance and functional diversity of SMCs observed jointly in low-SD.

Community composition, and not species richness, of microbes influences decomposer functional diversity in soil

Diversity-function relationships in producers, and how these are influenced by consumers, are well known. However, these are not well known for microbial decomposers in soil. It is also unknown whether and how consumers such as large mammalian herbivores influence soil microbial decomposer diversity-function relationships. We used a 14-year-old herbivore-exclusion experiment in the Trans-Himalayan drylands of northern India to address whether microbial functions vary with microbial diversity (both species richness and composition), and whether herbivores alter the diversity-function relationships. We analyzed soils from n = 10 paired grazed-and-fenced plots three times during the growth season of 2019. Data were from 16S rDNA gene amplicon sequencing of 7.6 million reads covering 1937 operational taxonomic units (OTU) of bacteria across 47 phyla (of which 924 OTUs were identifiable to genus level), and 1800 catabolic profiles across 30 substrates related to carbon metabolism. We found that functional diversity was positively related to microbial community composition, but not to species richness; it was also unaffected by large mammalian herbivore-exclusion to indicate resilience and resistance. This positive relationship between community composition and functional diversity challenges the prevailing notion of functional redundancy in hyper-diverse soil microbial communities since certain combinations of species could outperform others and determine decomposition processes and services. Structural equation models suggested that the strength of this relationship is favoured by availability of soil moisture. Microbial functions varied more strongly with temporal variables (e.g., seasonality) than with spatial variables (e.g., edaphic factors such as soil texture and pH). Although interpretations can be constrained by which and how many functions are investigated, the relationship was generalizable and robust once 16 or more functions were quantified. Decomposition in drylands may be particularly susceptible to how the identity of the microbial species, and not the number of species, responds to rising precipitation variability under ongoing and projected climate change.

Integrated Nutrient Management Practices and their Effect on Soil Health in Relation of Enzyme Dynamics and Biota in a Long-Term Diverse Cropping System in Vertisols of Central India

Organic farming is gaining popularity as it maintains food yields and soil health without harming the environment. However, there is a dearth of global data on enzymes involved in the carbon, nitrogen, phosphorus, and sulphur cycles; microbial elemental stoichiometry; and soil functional diversity. On the other hand, organic farming lacks the most sensitive biological components and enzyme activity based on soil quality indices. It all started in 2004 when four of India's largest soybean-based cropping systems participated in a trial to examine the viability of nutrient management in soybean-based cropping systems (soybean-wheat, soyabean-mustard, soybean-chickpea, and soybean-linseed). Herein, we report the findings of a soybean-wheat cropping system studied for Vertisol under six nutrient management practises. Chemical characteristics of the soil were studied before and after seeding. Enzyme activity, soil microbial biomass carbon (SMBC), and microbial count were studied in biological parameters. The chemical, biological and agronomic parameters of the soybean crop were statistically examined using the Randomized Block Design. The analysis of the various parameters from the surface soils (0–15 cm). The biological activity varied significantly between treatments. The agronomical indicators also exhibited significant values in the organically treated plot. Organic treatments improved agronomic conditions, stabilised soil, and improved its nutrient content, quality, and biological activity over time. The inorganically treated plot and the state recommended dose plot had the lowest nutritional content, as suggested by the lowest biological activity parameters. Soil fertility and nutrient availability were studied in this experiment in order to comprehend why switching from chemical to integrated nutrient application practises will be helpful towards the inception of a sustainable future.

Functional diversity and behavioral changes of microbial communities under salt affected soils

Salt-affected soils (SASs) are globally distributed especially in the arid and semi-arid regions of the world which highly affect the crop growth and productivity. The soil physico-chemical and biological properties largely vary with different types of SASs which trigger the crop yield, nutrient imbalance and soil quality. Therefore, to understand the changes in soil microbiology in relation to soil characteristics, a micro plot study was conducted to evaluate the impact of soil salinity/sodicity on physical, chemical properties at surface (0–15 cm) and subsurface (15–30 cm) soils in relation to soil microbial population, activities and functional diversity with focusing on community-level physiological profiling (CLPP) study. Five types of soils based on pH, electric conductivity (EC) and salt concentration maintained for last 25 years - highly saline, moderately saline, highly sodic, moderately sodic and normal were evaluated in micro plots to understand the changes in soil biological properties in relation to salt concentration. The results revealed that the highest value of pHs, ECe (EC of soil saturated paste extract), cation exchange capacity (CEC), exchangeable sodium percentage (ESP), sodium adsorption ratio (SAR), anions and cations concentrations, bulk density (BD), infiltration rate (IR), penetration resistance (PR) were observed in highly saline and highly sodic soils at surface and subsurface soil layer. In surface and subsurface layers, organic carbon (0.67 and 0.52 %) and available N (110 and 195 kg ha−1) were found higher under normal soils than SASs (% OC: 0.20–0.34 and 0.17–0.38; available N: 75–80 and 47–77 kg ha−1), respectively. In relation to changes in soil physicochemical properties, average well color development (AWCD) was found highest with normal soils followed by moderately saline and moderately sodic soils and lowest was found in highly sodic soils at surface soils which indicates interference of salts in metabolic activities of microbes. The utilization of amino acids, amines, carboxylic acids, phenolic compounds and polymers was highest for normal soils followed by moderately saline and lowest was recorded for highly sodic soils. But AWCD for carbohydrates was highest in highly saline soils, followed by highly sodic soils in contrast to normal soil and lowest was found under moderately sodic soils. Shannon diversity index (H) and substrate richness (SR) were found higher (3.19 and 24.07) in normal soils than SASs. Similarly, effect of salt load was also reflected on less soil enzymatic activities such as dehydrogenase, aryl sulfatase, invertase, etc. under varying types of SASs. Thus, with the increasing salt load, chemical and physical properties of soils were found to deteriorate and directly affected the microbial population, activities and their diversity in soil. This study indicated that soil physico-chemical properties, functional diversity, population and community of microbes were highly influenced by nature of salts and their concentration that may affect the soil quality and crop yield.

Different sex combinations of Populus cathayana affect soil respiration and tea litter decomposition by influencing plant growth and soil functional microbial diversity

Different sex combinations of Populus cathayana affect soil respiration and tea litter decomposition by influencing plant growth and soil functional microbial diversity

Tree canopy enhances Collembola functional richness and diversity across typical habitats of the Gorongosa National Park (Mozambique)

The role of tree canopies in protecting soil functional diversity is essential for ecosystems threatened by the longer lasting periods of drought, which are predicted to increase in the southern afro-tropical region. Nonetheless, biodiversity inventories of soil mesofauna are scarce in afro-tropical ecosystems, even in emblematic and well-studied protected areas, such as the Gorongosa National Park (GNP). Understanding the interrelationships between tree canopies and soil fauna functional diversity can provide insightful information for future adaptive management to protect wildlife and ecosystem services in the GNP, in the context of climate change. Here we assessed collembolan functional type richness and functional diversity in the dry period and during the rainfall across major GNP habitat types: miombo forests, mixed forests, and open savanna/floodplains. Besides the significant positive influence of rainfall, habitat types also influenced functional type’ richness and diversity of collembolan life-forms. Environmental gradients across habitat types, namely the area of tree canopy cover and its indirect effect on soil local conditions (pH and nutrient availability), explained collembolan functional parameters. Calcium concentrations and soil alkalinity significantly enhanced collembolan functional type richness and functional diversity, respectively. Collembola survival across GNP habitats depended on the canopy buffering in the dry sampling period. These results highlight the key role of tree canopies in creating suitable microhabitat conditions supporting soil functional diversity and the sustainability of soil processes and ecosystem services in GNP.

Drivers of soil organic carbon stock during tropical forest succession

Abstract Soil organic matter contributes to productivity in terrestrial ecosystems and contains more carbon than is found in the atmosphere. Yet, there is little understanding of soil organic carbon (SOC) sequestration processes during tropical forest succession, particularly after land abandonment from agriculture practices. Here, we used vegetation and environmental data from two large‐scale surveys covering a total landscape area of 20,000 ha in Southeast Asia to investigate the effects of plant species diversity, functional trait diversity, phylogenetic diversity, above‐ground biomass and environmental factors on SOC sequestration during forest succession. We found that functional trait diversity plays an important role in determining SOC sequestration across successional trajectories. Increases in SOC carbon storage were associated with indirect positive effects of species diversity and succession age via functional trait diversity, but phylogenetic diversity and above‐ground biomass showed no significant relationship with SOC stock. Furthermore, the effects of soil properties and functional trait diversity on SOC carbon storage shift across elevation. Synthesis. Our results suggest that reforestation and restoration management practices that implement a trait‐based approach by combining long‐lived and short‐lived species (conservative and acquisitive traits) to increase plant functional diversity could enhance SOC sequestration for climate change mitigation and adaptation efforts, as well as accelerate recovery of healthy soils.

Cerium oxide nanoparticles (nCeO2) exert minimal adverse effects on microbial communities in soils with and without biosolids amendment.

Increased use of nano-cerium oxide (nCeO2) in an array of industrial applications has raised environmental concerns due to potential increased loadings to the soil environment. This research investigated the potential adverse effects of nCeO2 (10-30 nm) on the soil microbial community in two exposure scenarios: direct application to soil, and indirect application to soil through chemical spiking of biosolids, followed by mixing into soil. Total Ce in test soils without, and with biosolids amendment, ranged from 44 to 770, and 73 to 664 mg Ce kg-1 soil, respectively. In order to help distinguish whether observed effects were elicited by the solid-phase colloids or the activity of dissolved Ce, a soluble Ce salt (Ce (NO3)3) treatment was included in select assays. A suite of tests was used to investigate effects on critical processes: microbial growth (heterotrophic plate count), microbial activity (organic matter (OM) decomposition, enzyme activity and, nitrification) and diversity (structural and functional). Although results showed significant inhibition on microbial growth in soil without biosolids amendment at ≥ 156 mg Ce kg-1 soil by week 5, these results were inconsistent and non-significant thereafter. In general, nCeO2 showed no evidence of consistent adverse effects on OM decomposition, nitrification, soil enzyme activities and functional diversity. Leucine aminopeptidase showed significant (p< 0.05) stimulatory effects over time at ≥ 44 mg Ce kg-1 in soils without biosolids, which was not observed in soils with biosolids amendment. The lack of inhibitory effects of nCeO2 may be attributed to its low solubility; Ce in soil extracts (0.01 M CaCl2) were all below detection (< 0.003 mg kg-1) in the nCeO2-spiked soils, but detectable in the Ce (NO3)3 samples. In contrast, soluble Ce at 359 mg Ce kg-1 showed a significant reduction in OM decomposition and effects on microbial genomic diversity based on the 16S rDNA data in soils with and without biosolids amendment (359 and 690 mg Ce kg-1). The nCeO2 behaviour and effects information described herein are expected to help fulfill data gaps for the characterization of this priority nanomaterial.

Horizontal Variation Characteristics of Alpine Grassland Soil Function and Vertical Changes Along Soil Genetic Horizons in the Three-River Headwaters Region

The Three-River Headwaters region is a hotspot for studying the response of soil function to climate change. To study the horizontal variation characteristics of alpine grassland soil function and vertical changes along soil genetic horizons, soil functional indicators (including respiration, nitrogen conversion rate, and enzymatic activity) of different genetic horizons in alpine grassland soil profiles and their correlations with environmental factors were analyzed. The results showed that there were no significant differences in soil functional characteristics between alpine meadows and steppes, and topsoil had higher respiration rates, nitrogen conversion rates, and enzymatic activities than those of subsoil. Total nitrogen was a key driver of soil functional characteristics in different genetic horizons, explaining 18.3%, 21.4%, and 27.5% of the horizontal variation in functional characteristics, respectively. Climate and vegetation factors mainly affected soil function indirectly by changing soil physicochemical properties in topsoil, but atmospheric nitrogen deposition still affected soil function in subsoil. These results indicate the significant nitrogen limitation of alpine grassland soil in the Three-River Headwaters region, and the findings provide a new insight into the maintenance of soil functional diversity and the response to climate change in the context of global climate change.

Functional diversity and soil nutrients regulate the interannual variability in gross primary productivity

Abstract Global change, encompassing rising temperatures and an increase in extreme precipitation events, has influenced vegetation photosynthesis; this can be seen in the gross primary productivity (GPP) of terrestrial ecosystems, which, over time affects the global carbon cycle. The impact of climate on interannual variability in GPP (GPPIAV) has been extensively explored in the literature. Other changing factors driven by global change, such as biodiversity and soil nutrient availability, are vital in predicting the future of the biosphere. However, the roles of these factors remain unclear. We combined (i) data from 454 community plots collected using standard protocols from 2013 to 2019 across China, (ii) plant trait data and phylogenetic information of more than 2500 plant species, and (iii) soil nutrient data that we measured. Using these data from 72 “real‐world” ecosystems located across a range of environmental conditions and species pools, we investigated the role of environmental factors including temperature, precipitation and soil nutrients and multifaceted diversity (i.e. species richness, hypervolume‐based functional diversity, and phylogenetic diversity) in mediating the magnitude of GPPIAV using multi‐model averaging and structural equation modelling. We found that soil nutrients and functional diversity are the main determinants of the magnitude of GPPIAV and that climate effects are predominantly mediated by multifaceted diversity. Synthesis. We provide strong evidence that ecosystems with higher biodiversity have less variable annual biomass production and decrease the extent of GPPIAV through compensatory effects across diverse ecosystems. Nutrient‐rich ecosystems are likely to buffer the impact of climate variability on ecosystem carbon uptake better than nutrient‐poor ecosystems. Our results demonstrate that biodiversity plays a crucial role in buffering the effects of environmental variability on carbon uptake in terrestrial ecosystems.

Investigating the metagenomics of the bacterial communities in the rhizosphere of the desert plant Senna italica and their role as plant growth promoting factors

Natural microbial communities associated with desert plants are found in soils that face nutrient deficiencies and extreme environments, including salinity and drought. In this study, 16S rRNA metagenomic sequencing was used to screen and identify bacterial assemblies associated with the desert plant Senna italica, obtained from diverse soil samples located in the Asfan region, northeast of Jeddah, Saudi Arabia. Several studies found Senna italica as a valuable medicinal plant for treating different diseases; however, a few studies were done on its association with bacterial communities under drought conditions. This study aimed to identify bacterial communities present in the drought soil environment of the Senna italica plants. To approach our goals, we applied metagenomic techniques, discovering a new bacterial strain beneficial for biotechnological applications. Our results showed that the analysis of the 16S rRNA sequences at the taxonomic phylum level detected 15 phyla of bacterial populations in the soil samples. The most prevalent was kept for further research. Our findings demonstrated that rhizospheric bacteria may be used as indicators of plant growth rate and survival ability in hostile environments. Studying the soil microbiome's taxonomic, phylogenetic, and functional diversity will facilitate identifying new candidates for biological agents that can be used to improve agricultural and industrial processes.

Relative importance of soil properties and functional diversity to the spatial pattern of the forest soil nitrogen

Surface soil nitrogen (SN) is the main source of plant nutrient uptake, and its dynamic change is related to forest productivity, ecosystem carbon and nitrogen cycles, and water conservation. However, few studies have investigated the factors influencing SN. The linear mixing effect and generalized additivity model were used to investigate the spatial patterns and influencing factors of SN by collecting and measuring the total nitrogen content of forest soil samples in the middle and lower reaches of the Xijiang River Basin (XRB). We found that the total nitrogen content in broad-leaved forest soils was significantly higher than that in coniferous forest soils. Forest SN was influenced by soil properties and diversity indicators, and the full model constructed by influencing factors was more applicable to broad-leaved forests. Soil properties were the main explanatory factor for SN (53.53% in the full model, 61.02% in broad-leaved forests), with sub-surface soil nitrogen (sub SN) being the largest explanatory quantity factor (48.52% in the full model, 58.04% in broad-leaved forests). Therefore, forest management in the XRB should avoid damaging the sub-surface soils to prevent nitrogen loss. In the context of global change, the further study of the effect of nitrogen deposition on SN is warranted.

Soil biota community structure and litter traits of grape vine plantation and natural ecosystem from Southern Brazil

Vitis vinifera is a common plant species cultivated in Southern Brazil for vine production. Although this plant species is commonly found near the Mixed Ombrophilous Forest, the V. vinifera plantation is cultivated in areas for a long-term thus changing the soil ecosystem and functional diversity. We aimed to compare the soil chemical properties, soil biota assemblage, litter traits, decay rate and priming effect in the two adjacent environments (e.g., grape vine plantation vs. natural ecosystem). Soil chemical properties, soil biota community composition, and litter traits of V. vinifera plantation were compared with an adjacent natural ecosystem (e.g., Mixed Ombrophilous Forest) from September 2019 to June 2021. Litter decay rate and priming effect was estimated by using native tree residues on litter bags in both studied environments. We also assessed the influence of soil biota on decay rate through a litterbag assay. Our results showed that both studied environments differed in soil chemical properties and soil biota community composition. However, in the V. vinifera plantation litter decay rate, and priming effect were higher, due to the presence and activities of soil organisms from Collembola - Paronellidae. Thermal amplitude, litter quality, and soil organisms’ activity were the main factors contributing to the data variance. Both native tree residues, A. angustifolia and D. sellowiana, showed the highest decay rate and priming effect in the V. vinifera plantation. Our work increases the understanding of the soil food web and ecological processes (litter deposition and nutrient cycling) into subtropical ecosystems. The V. vinifera plantation following a monocropping system does not provide resources to create a well-developed soil food web, which overtime creates negative plant-soil feedback when compared to the natural ecosystem. However, our study opens a new perspective for a future agroforestry system using two endangered species from the Brazilian Mixed Ombrophilous Forest seeking for vine production, soil sustainability, and biodiversity conservation.