Soil Factors Research Articles

Evaluation of aluminum tolerance diversity in Avena sativa L. from the VIR collection

Background. Oat is an important food and feed cereal crop in Russia. The area under oats is 10 million ha worldwide, and 3 million ha in Russia. Acid soils with excessive content of exchangeable aluminum occupy almost every third hectare in the exUSSR territory. Oats are relatively resistant to unfavorable soil factors. Among cereal crops, oat is second only to rye and triticale in terms of resistance to exchangeable Al forms. Despite the crop’s high environmental plasticity, an important condition for obtaining sustainable oat yields is the development of new cultivars with resistance to adverse environmental factors, including metal toxicity and high soil acidity.The objective of this work was to search for oat cultivars resistant to soil stressors (excess of Н+ and Al3+) for use in breeding for edaphic resistance.Materials and methods. The research material included 687 oat accessions from the VIR global plant genetic resources collection. The accessions underwent laboratory evaluation of their aluminum tolerance at the initial growth and development stages using the method of measuring radicle growth after the exposure to aluminum stress. Reproducibility of the used modification of the method was mathematically proved.Results and discussion. Significant variation in the resistance to the studied stressor was observed among the accessions. The regions acting as sources of valuable aluminum resistance genes were identified for the crop. The accessions selected for their high resistance to exchangeable aluminum can be used in breeding programs to develop high-yielding oat cultivars with edaphic resistance.

Two‐particle debris flow simulation based on SPH

AbstractDebris flow is a highly destructive natural disaster, necessitating accurate simulation and prediction. Existing simulation methods tend to be overly simplified, neglecting the three‐dimensional complexity and multiphase fluid interactions, and they also lack comprehensive consideration of soil conditions. We propose a novel two‐particle debris flow simulation method based on smoothed particle hydrodynamics (SPH) for enhanced accuracy. Our method employs a sophisticated two‐particle model coupling debris flow dynamics with SPH to simulate fluid‐solid interaction effectively, which considers various soil factors, dividing terrain into variable and fixed areas, incorporating soil impact factors for realistic simulation. By dynamically updating positions and reconstructing surfaces, and employing GPU and hash lookup acceleration methods, we achieve accurate simulation with significantly efficiency. Experimental results validate the effectiveness of our method across different conditions, making it valuable for debris flow risk assessment in natural disaster management.

Global synthesis on the response of soil microbial necromass carbon to climate-smart agriculture.

Climate-smart agriculture (CSA) supports the sustainability of crop production and food security, and benefiting soil carbon storage. Despite the critical importance of microorganisms in the carbon cycle, systematic investigations on the influence of CSA on soil microbial necromass carbon and its driving factors are still limited. We evaluated 472 observations from 73 peer-reviewed articles to show that, compared to conventional practice, CSA generally increased soil microbial necromass carbon concentrations by 18.24%. These benefits to soil microbial necromass carbon, as assessed by amino sugar biomarkers, are complex and influenced by a variety of soil, climatic, spatial, and biological factors. Changes in living microbial biomass are the most significant predictor of total, fungal, and bacterial necromass carbon affected by CSA; in 61.9%-67.3% of paired observations, the CSA measures simultaneously increased living microbial biomass and microbial necromass carbon. Land restoration and nutrient management therein largely promoted microbial necromass carbon storage, while cover crop has a minor effect. Additionally, the effects were directly influenced by elevation and mean annual temperature, and indirectly by soil texture and initial organic carbon content. In the optimal scenario, the potential global carbon accrual rate of CSA through microbial necromass is approximately 980 Mt C year-1, assuming organic amendment is included following conservation tillage and appropriate land restoration. In conclusion, our study suggests that increasing soil microbial necromass carbon through CSA provides a vital way of mitigating carbon loss. This emphasizes the invisible yet significant influence of soil microbial anabolic activity on global carbon dynamics.

Most High Mountainous Areas Around the World Present Elevation‐Dependent Aridification After the 1970s

AbstractThe research on the trends of mountainous aridity and the issue of elevation‐dependent aridity (EDA) has long been hindered by limitations in data validity. In this study, we present global monthly merged data sets of Vapor Pressure Deficit and Aridity Index (AI) from 1960 to 2020, aiming to detect and attribute elevation‐dependent patterns of atmospheric and soil aridity in six representative high mountainous areas worldwide. Our findings reveal that most of the mountainous regions experienced significant aridification after the 1970s (p < 0.05). The Rocky Mountains and Ethiopian Highlands are identified as the most vulnerable areas, with both atmospheric and soil aridity increasing by 13% across all elevation gradients. Significant humidification has been observed only in High Asian Regions at 4,000 m above sea level with an approximate decrease of 11% in soil AI. In both temporal and spatial patterns, soil aridity exhibits stronger heterogeneity compared to atmospheric aridity, with certain regions and seasons showing humidification, despite the overall aridification trend. Elevation‐dependent aridity is observed in two‐thirds of the mountains, but whether high altitude alleviates or amplifies aridity depends on the pattern of precipitation changes at different elevations. The rise in air temperature is the primary driving factor for soil and atmospheric aridification, contributing to over 50% of each. In two‐thirds of the regions, changes in precipitation exacerbate soil aridity. Simulations show that human activities are closely related to the ongoing prolonged atmospheric aridification. This study contributes to a comprehensive understanding of global mountainous aridity evolution projected under climate change.

Microorganisms facilitated the saline‐alkali soil remediation by biochar: Soil properties, microbial communities, and plant responses

AbstractSaline‐alkali soil degradation is a significant environmental problem with a negative impact on sustainable agroforestry development. Therefore, efficient remediation methods are urgently required. A potential solution to this problem is using biochar produced from bamboo waste and inoculated with plant growth‐promoting microbes as cleaner production materials for saline‐alkali soil. The present study investigated the potential of combining biochar, microbes, and dwarf bamboo to improve saline‐alkali soil. Different application rates (1%, 3%, and 5% of soil mass) of biochar were added to coastal saline soil planted with dwarf bamboo (Pleioblastus argenteastriatus) in pot experiments. Soil physicochemical properties, microbial communities, and plant responses were systematically studied. Bamboo and microbial‐modified biochar effectively decreased soil pH and electrical conductivity and increased soil nutrient contents. Compared with untreated soil, the relative abundance of the dominant bacterial phyla Acidobacteria, Actinobacteria, and Chloroflexi, and dominant fungal phyla Basidiomycota increased after applying biochar and modified biochar. With the increase in application concentration, the antioxidant activities of modified biochar decreased, biochar peroxidase and catalase content decreased, and the malondialdehyde content of bamboo biochar and microbial‐modified bamboo biochar decreased. The biomass of bamboo with added biochar and modified biochar was significantly higher than that of untreated soil. Comprehensive correlation and redundancy analyses showed that the bacterial and fungal communities were greatly affected by soil factors, especially soil pH, electrical conductivity, total organic carbon, potassium, and sodium ions. The findings of this study suggest that 5% bamboo biochar and 3% modified biochar benefit soil remediation, improve the stress resistance of dwarf bamboo, and enhance plant growth. Therefore, combined biochar–microbe remediation has great potential for the sustainable improvement of saline‐alkali soil.

AgriSolutions: Innovations in Crop Disease Prediction, Crop Recommendation, and E Commerce

Abstract: Crop disease prediction and crop recommendation are important steps towards sustainable agriculture. The use of deep learning, EfficientNet_v2 and image processing technologies can help in improve accuracy in these tasks. Identification of plant diseases and recommendation of crops cannot maximize only yield production but can be supportive for varied types of agricultural practices The existing system of crop recommendation employs data analysis to suggest suitable crops based on soil and climate factors, while disease prediction system utilizes predictive models to anticipate and prevent crop diseases. In this Paper, we propose a model that combines these techniques to accurately identify to recommend suitable crops based on the Soil Parameters and climate conditions of the farm. Our proposed model achieved and classify plant diseases, recommend suitable crops based on the soil condition. To achieve this, we trained a deep neural network on a large dataset of images of healthy and diseased plants, and performed image preprocessing.

Studying the Role of Soil Factors on Degree of Degradation of DNA of Human Remains

Generating a DNA profile using autosomal Short Tandem Repeat (STR) DNA allele from skeletal remains is a crucial step in the identification process for mass disaster and unidentified person situations. The capacity to extract substantial amounts of relevant DNA from bones, which were highly durable biological components that can withstand soil elements and climatic conditions over long periods of time, would be advantageous. 70 femur male bone samples were collected from two different environmental mass graves (Al-Mahaweel massgrave) in Babil governorate and (Al-Saqlawiya massgrave) in Al-Anbar governorate in Iraq. The DNA from bone samples extracts were assessed by capillary electrophoresis and a standardized set of short tandem repeat (STR) loci are analyzed using Mutiplex 21 STR loci System to allow human identification by matching the profile of the dead individuals with their relatives. From these two different sites; soil samples were collected to analyze and study the different environmental factors and find a relation between the degree of preservation or degradation with these factors like temperature, humidity, salinity, PH and texture of soil and find how these factors can affect on pattern of degradation of DNA profiles. The average of the percentage of the detected alleles in each locus in the two sites; were 87\% for Al-Mahaweel site and 32\% for Al- Saqlawiya site. we found that clay soil, low salt concentration, PH slightly alkaline and low humidity for Al-Mahaweel site; all participate in DNA preservation while the chalky and very high salt concentration of Al- Saqlawiya site soil; all participate in DNA degradation. Predicting the effect of these factors on the quality of the DNA profiles can be helpful in finding better solutions for many complications that may face the process of analyzing samples and finding sufficient informative profiles.

Pilot study assessing effects of selected soil factors on the accumulation of hesperidin, nobiletin and tangeretin in pericarps of Citrus reticulata ‘Chachi’

Pilot study assessing effects of selected soil factors on the accumulation of hesperidin, nobiletin and tangeretin in pericarps of Citrus reticulata ‘Chachi’

Vertical differences in carbon metabolic diversity and dominant flora of soil bacterial communities in farmlands

The carbon cycle in soil is significantly influenced by soil microbes. To investigate the vertical distribution of the dominant groups in agricultural soil and the carbon metabolic diversity of soil bacteria, 45 soil samples from the 0 ~ 50 cm soil layer in Hunan tobacco–rice multiple cropping farmland were collected in November 2017, and the carbon diversity of the soil bacterial community, bacterial community composition and soil physical and chemical properties were determined. The results showed that the carbon metabolic capabilities and functional diversity of the soil bacterial community decreased with depth. The three most widely used carbon sources for soil bacteria were carbohydrates, amino acids, and polymers. The dominant bacterial groups in surface soil (such as Chloroflexi, Acidobacteriota, and Bacteroidota) were significantly positively correlated with the carbon metabolism intensity. The alkali-hydrolysable nitrogen content, soil bulk density and carbon–nitrogen ratio were the key soil factors driving the differences in carbon metabolism of the soil bacterial communities in the different soil layers.

Changes in diversity of marsh plant communities under shrub encroachment in Sanjiang Plain and their soil control factors

In this study, we explored the changes in plant community diversity and their relationship with soil factors under shrub encroachment pressure by selecting four marsh areas in Sanjiang Plain with different degrees of shrub cover (a, 0≤a≤100%), including marsh with no shrub encroachment (a=0), light shrub encroachment (0<a≤30%), medium shrub encroachment (30%<a≤70%), and heavy shrub encroachment (70%<a≤100%). The results showed that shrub encroachment was the main reason for the heterogeneity of plant community composition in marsh. With shrub encroachment, the dominant species Deyeuxia angustifolia was replaced by Spiraea salicifolia, whereas Carex schmidtii disappeared. However, the importance values of Sanguisorba tenuifolia and Stellaria radians in the community significantly increased by 0.8- and 9.0-fold, respectively. Shrub encroachment resulted in changes of plant community diversity in marsh. The highest α and β diversity in plant community were observed under light shrub encroachment area, whereas there were no significant differences in Shannon and Simpson indices between heavy and no shrub encroachment areas, despite their similarity in plant community composition was the lowest. All the studied soil factors were significantly affected by shrub encroachment, except total phosphorus. There were significant reductions in soil moisture, organic carbon, and total nitrogen in heavy marsh shrub encroachment area by 32.6%, 69.3%, and 66.1%, respectively compared with that in no marsh shrub encroachment area, whereas soil total potassium and total magnesium significantly increased by 33.8% and 40.6%, respectively. Results of redundancy analysis showed that soil organic carbon, moisture content, total nitrogen, and N:P were the main factors controlling the diversity changes of marsh plant community under shrub encroachment pressure.

Characteristics of leaf stoichiometry and the driving factors of Ammopiptanthus mongolicus, China

The stoichiometric characteristics of leaves can reflect environmental adaptation of plants, and thus the study of the relationship between them is helpful for exploring plant adaptation strategies. In this study, taking the national second-level key protection species, Ammopiptanthus mongolicus, as the research object, we set up 26 plots to collect samples, and measured the content of carbon (C), nitrogen (N), phosphorus (P) and water use efficiency (WUE) of leaves. We analyzed the relationship between leaf stoichiometric characteristics and WUE, and quantified the contributions of soil, climate, and water use efficiency to the variations of leaf stoichiometry. The results showed that C, N, and P contents in the leaves were (583.99±27.93), (24.31±2.09), and (1.83±0.06) mg·g-1, respectively. The coefficients of variation were 4.8%, 8.6%, and 3.2%, respectively, all belonging to weak variability, indicating that foliar contents of C, N and P tended to a certain stable value. The average value of N:P was 13.3, indicating that the growth of A. mongolicus was mainly limited by N. WUE was not correlated with leaf C content, but was significantly positively correlated with leaf N and P contents and N:P, and significantly negatively correlated with C:N and C:P, indicating that there was a linear synergistic trend between WUE and leaf nutrient content. The main factors influencing leaf C content and C:P were climatic factors, the leaf N content and N:P were mainly affected by soil factors, and the water use efficiency mainly affected leaf P content and C:N, indicating that the driving factors of different stoichiometric characteristics were different. The results could help eva-luate the habitat adaptation of desert plants, which would provide a theoretical basis for the conservation and management of A. mongolicus.

Understory specific species appearances indicate the soil improvement of low-function Platycladus orientalis forest in Beijing’s mountainous areas

How to assess the effect of ecosystem restoration is a trending topic with all the restoration projects and ecosystem function studies in recent years. Although many studies have used different indicators and methods to evaluate ecosystem restoration effects, it needs a lot of site works to acquire the data. Low-function Platycladus orientalis forest restoration program in Beijing mountainous area has been started since 2002, in this study, the understory species of 92 plots were investigated and recorded. We assumed that the effect of ecosystem restoration would improve site conditions, especially for the soil conditions which might lead to the appearance of new species. The relationship between understory species and eleven site condition factors was elucidated by means of canonical correspondence analysis (CCA), further, specific species were chosen to represent the improvement and possible growth areas of specific species was predicted by Maximum Entropy model. Results shown that Spiraea pubescens, Deutzia parviflora, Chrysanthemum chanetii, Themeda triandra, Oplismenus undulatifolius were the main understory species which were sensitive to environmental factors, and their distribution were related to soil factors closely. The species of Spiraea pubescens, Chrysanthemum chanetii, Oplismenus undulatifolius had strong indication to soil nutrient, the appearances would happen when the comprehensive index of soil nutrient was above 81,64 and 61 respectively. The appearance of Chrysanthemum chanetii and Oplismenus undulatifolius would indicate that the soil nutrient level was in or above the range of medium, and the appearance of Spiraea pubescens would mean that the soil nutrient level was in or above the range of high in low-function Platycladus orientalis forest of Beijing mountainous area. Our study indicates that the specific species could as an indicator to reflect or evaluate the ecosystem restoration effect.

Patterns and drivers of tree species diversity in a coniferous forest of northwest China

IntroductionUnderstanding the pattern of species diversity and underlying ecological determinants driving a forest ecosystem is fundamental to conservation biology and forest management. Boreal forests play an irreplaceable role in providing ecosystem services and maintaining the carbon cycle globally, yet research attention remains disproportionately limited and lacking throughout time.MethodsBased on field measurement data from a large (25 ha) fully-mapped coniferous forest plot, the present study quantified patterns of species diversity and their determinants in Kanas of Xinjiang, northwest China. We applied linear regression analysis to test the effects of biotic and soil factors on alpha-diversity and local contribution of beta diversity (LCBD), and then we adopted path analysis to test the determinants that affected the species diversity index.Results and discussionOur results revealed that alpha-diversity indices did not vary greatly across different subplots, and richness value (between 2 and 6) was low in Kanas. Noteworthy is the discerned negative association between the average diameter at breast height (DBH) and species richness, suggesting that areas with smaller DBH values tend to harbor greater species richness. For beta-diversity, a higher value was observed in the substory layer (0.221) compared to both the canopy layer (0.161) and the understory layer (0.158). We also found that the species abundance distance matrix of biological and soil environmental factors were significantly correlated with species geographic distance matrices. More importantly, our results showed that average DBH and soil pH would affect the alpha diversity indices, and average DBH, soil Ph, average height and soil total Phosphorous would affect the beta diversity indices. Soil pH also indirectly affected the LCBDunder, LCBDsub, and LCBDcan (p ≤ 0.001), upon mediation of alpha diversity indices. Overall, our results provide crucial revelations about species diversity patterns in boreal forests, and insights that can support the protection of forest biodiversity in China.

Effects of soil pH on the growth, soil nutrient composition, and rhizosphere microbiome of Ageratina adenophora.

Ageratina adenophora is an invasive weed species found in many countries. Methods to control the spread of this weed have been largely unsuccessful. Soil pH is the most important soil factor affecting the availability of nutrients for plant and impacting its growth. Understanding the mechanisms of the influence of soil pH on the growth of A. adenophora may help to develop effective control measures. In this study, we artificially changed the soil pH in pot experiments for A. adenophora. We studied the effects of acidic (pH 5.5), weakly acidic (pH 6.5), neutral (pH 7.2), and alkaline (pH 9.0) soils on the growth, availability of soil nutrients, activity of antioxidant enzymes, levels of redox markers in the leaves, and the structure and diversity of the rhizosphere microbiome. Soil with a pH 7.2 had a higher (47.8%) below-ground height versus soils of pH 5.5 at day 10; plant had a higher (11.3%) above-ground height in pH 7.2 soils than pH 9.0 soils at day 90; no differences in the fresh and dry weights of its above- and belowground parts, plant heights, and root lengths were observed in plants growing in acid, alkaline, or neutral pH soil were observed at day 180. Correspondingly, the antioxidant enzymes SOD (superoxide dismutase), POD (peroxidase), CAT (catalase) and redox markers GSH (glutathione) and MDA (malondialdehyde) were measured in the leaves. Significant differences existed in the activities of CAT and the levels of GSH between those growing in acidic and alkaline soils and those in neutral pH soil at day 90; however, only lower (36.8%) CAT activities in those grown at pH 5.5 than those grown at pH 7.2 were found at day 180. Similarly, significant differences in available P (16.89 vs 3.04 mg Kg-1) and total K (3.67 vs 0.96 mg Kg-1), total P (0.37 vs 0.25 g Kg-1) and total N (0.45 vs 1.09 g Kg-1) concentrations were found between the rhizosphere soils of A. adenophora grown at pH 9.0 and 7.2 at day 90; no such differences were seen at day 180. High throughput analyses of the 16S rRNA and ITS fragments showed that the rhizosphere microbiome diversity and composition under different soil pH conditions changed over 180 days. The rhizosphere microbiomes differed in diversity, phylum, and generic composition and population interactions under acid and alkaline conditions versus those grown in neutral soils. Soil pH had a greater impact on the diversity and composition of the prokaryotic rhizosphere communities than those of the fungal communities. A. adenophora responded successfully to pH stress by changing the diversity and composition of the rhizosphere microbiome to maintain a balanced nutrient supply to support its normal growth. The unusual pH tolerance of A. adenophora may be one crucial reason for its successful invasion. Our results suggest that attempts use soil pH to control its invasion by changing the soil pH (for example, using lime) will fail.

Identification of geographic, climatic, and soil factors dominating Stevia rebaudiana yield and quality

Raising crop yields and quality through plant ecological research has become an important approach to sustainably improving crop products. Stevia rebaudiana is widely introduced and cultivated around the world because of the continuous increase in demand for steviol glycosides. When selecting regions or plots suitable for high-yield and high-quality cultivation, it is necessary to understand the main ecological factors that contribute to the formation of S. rebaudiana yield and quality. In this study, sampling plots from different geographic and climatic regions in Xinjiang and Jiangsu were selected for S. rebaudiana cultivation. The geographic, climatic and soil ecological factors were analyzed based on a PLSR (partial least squares regression) model to discover the potentially influential factors in the yield and quality formation of the crop. The results suggest that not all geographic and climatic ecological factors contributed to yield formation; however, these factors, such as latitude, altitude and annual sunshine duration, had high or moderate influences on the concentration of each steviol glycoside and total steviol glycoside. Soil organic matter (OM), total potassium (TK), available potassium (AK), zinc (Zn), and catalase (CAT) had high or moderate effects on the concentrations of each steviol glycoside and total steviol glycoside. However, the other soil factors showed variability in the extent to which they drove the steviol glycosides. The study contributes to a more profound understanding of the ecological driving mechanisms of S. rebaudiana yield and quality formation. The yield or steviol glycoside concentrations of sweetleaf may be improved by modifying certain key ecological factors.

Weed control efficacy and dry bean response to preemergence herbicide incorporation timing

AbstractField experiments were conducted in 2021 and 2022 to evaluate the effect of irrigation timing on S‐ethyl‐N,N‐dipropylthiocarbamate (EPTC), flumioxazin, pyroxasulfone, and flumioxazin + pyroxasulfone weed control efficacy and safety in dry bean (Phaseolus vulgaris L.). Treatments consisted of EPTC (3430 g ai ha−1), flumioxazin (53.6 g ai ha−1), pyroxasulfone (119 g ai ha−1), and flumioxazin + pyroxasulfone (70.4 + 89.3 g ai ha−1) incorporated with overhead irrigation at 1, 4, and 8 days after herbicide treatment (DAT). A nontreated and hand‐weeded check were included for comparison. Delaying irrigation until 8 DAT resulted in 11% and 19% injury in the pyroxasulfone and flumioxazin + pyroxasulfone treatments, respectively, but the crop recovered within 5 weeks after treatment. Delaying irrigation until 8 DAT increased total weed dry weight by 52%. Generally, flumioxazin + pyroxasulfone provided better weed control compared to flumioxazin or pyroxasulfone applied alone. Irrigation timing did not influence dry bean yield. Seed yield was 160 kg ha−1 in the nontreated check and 2521 kg ha−1 in the hand‐weeded check. Seed yield in the flumioxazin + pyroxasulfone treatment (2425 kg ha−1) was similar to the hand‐weeded check. Flumioxazin + pyroxasulfone provided very good weed control with acceptable crop safety. While irrigation timing may play a role in flumioxazin or pyroxasulfone injury, other soil and environmental factors may influence dry bean response to these herbicides.

Short-Term Simulated Warming Changes the Beta Diversity of Bacteria in Taiga Forests’ Permafrost by Altering the Composition of Dominant Bacterial Phyla

Permafrost is widely degraded in the context of global warming. The spatial distribution of soil microbes in these cold habitats has received a lot of attention. However, knowledge on the changes in permafrost microbial communities following permafrost thaw is still limited. We used permafrost soil from a taiga forest for indoor experiments using pristine soil as a control (CK, −2 °C), simulating warming for 15 days at temperatures of 0 °C (T1), 2 °C (T2), and 4 °C (T3). Amplicons of the hypervariable V4 region of the bacterial 16S rRNA gene were sequenced to identify bacterial communities present in the soils of pristine and warming treatments. Warming increased the average relative abundance of Proteobacteria (5.71%) and decreased that of Actinobacteriota (7.82%). The Beta diversity changed (p = 0.001) and significantly correlated with the pH, microbial biomass carbon (MBC), and available potassium (AK) of the soil (p &lt; 0.05). Warming further increased the Alpha diversity (Simpson index), changing the functional pathways of the bacterial communities, whereby secondary functional pathways produced significant correlations with bacterial phyla (p &lt; 0.05). Combined, the results indicated that short-term warming altered the Beta diversity of soil bacteria in a taiga forest’s permafrost soil by decreasing the abundance of Actinobacteria and increasing that of Ascomycetes, while pH, MBC, and AK were identified as the soil factors influencing the structure and diversity of the bacterial communities.

Climate Interprets Saturation Value Variations Better Than Soil and Topography in Estimating Oak Forest Aboveground Biomass Using Landsat 8 OLI Imagery

The optical saturation problem is one of the main factors causing uncertainty in aboveground biomass (AGB) estimations using optical remote sensing data. It is critical for the improvement in AGB estimation accuracy to clarify the relationships between environmental factors and the variations in optical saturation values (OSVs). In this study, we obtained the OSVs for 20 districts and clarified the individual, interactive, and comprehensive effects of climate, soil, and topographical factors on the OSV variations. The results are as follows: (1) the range of the OSVs was from 104 t/hm2 to 182 t/hm2 for the 20 districts; (2) the soil factor had the greatest (−0.635) influence on the OSVs compared to climate and topography; (3) the highest interaction effect (−0.833) was between climate and soil; (4) the comprehensive effect of the three environmental factors on the OSVs was obvious, and the correlation coefficient was 0.436. Moreover, the mean temperature of the coldest quarter (MCQMean) had the highest effect on the OSVs. The results indicate that environmental factors significantly affect the variation in OSVs through their individual, interactive, and comprehensive effects. Our findings provide a valuable reference for reducing the uncertainty caused by spectral saturation in AGB estimations using optical remote sensing data.

Does local soil factor drive functional leaf trait variation? A test on Neilingding Island, South China.

Leaf traits were affected by soil factors and displayed varietal differences in forest. However, few examples have been reported on the Island ecosystems. We comprehensively investigated 9 leaf traits (leaf length, leaf width, leaf area, SLA, leaf fresh weight, leaf C content, leaf N content, leaf K content, leaf C:N ratio) of 54 main subtropical woody species and soil parameters (soil pH, total C content, total N content, total K content, available N content, available P content, available K content and soil moisture) in Neilingding Island, Shenzhen, southern China. Intra-and interspecific variation of leaf traits were measured and their correlations with soil parameters were explored. The interspecific variations of leaf C:N ratio, leaf N content and leaf fresh weight were higher than their intraspecific variations. The intraspecific variation of leaf K content was larger than that of interspecific one, accounting for 80.69% of the total variance. Positive correlations were found among intraspecific coefficients of variations in leaf morphological traits. The correlation analysis between the variation of intraspecific traits and the variation of soil parameters showed that changes in soil factors affected leaf morphology and stoichiometry. The interaction between soil moisture and soil available P content was the key factor on intraspecific variations of leaf traits including leaf area, leaf fresh weight, leaf C and leaf K content. We concluded that leaf traits of plants in the island were tightly related to soil parameters. Soil parameters, especially soil moisture and available P content, affected plant leaf morphology and stoichiometry at the local scale.

Soil quality assessment of oak forests invaded by moso bamboo (Phyllostachys edulis) in the northern subtropics

Soil quality is closely related to the evolution of forest ecosystems, especially in the context of global warming; therefore, it is essential to study the changes in soil quality caused by the invasion of moso bamboo in its habitat. In this study, we selected plantation forests and natural secondary forests with typical vegetation of the northern subtropics, Quercus acutissima plantation (QAP) and oak secondary forest (OSF), collected plant community and soil physicochemical data, and established a soil quality index (SQI) to assess how moso bamboo invasion affects soil quality. In addition, the mechanisms driving the moso bamboo invasion effects on soil quality were investigated using a partial least squares structural equation model (PLS-SEM). The results demonstrated that: (1) Moso bamboo invasion significantly affected community structure and soil physicochemical properties, there were inconsistent changes in soil physicochemical indicators in oak forests of different origins, and in general the effects of moso bamboo expansion on soil physicochemical properties were concentrated in the topsoil (0–20 cm). (2) Soil bulk density (BD), total soil porosity (TSP), total nitrogen (TN), and available potassium (AK) comprised the minimum data set (MDS) used to calculate the SQI, and the SQI of oak forests of different origins ranged from 0.48 to 1, and the invasion of moso bamboo led to a significant decrease in the SQI of the surface layer of QAP. A redundancy analysis (RDA) showed that soil quality assessment factors were closely related to community structure and the PLS-SEM indicated that moso bamboo invasion indirectly affected surface soil quality through its effects on community and soil factors. The results showed that moso bamboo invasion had different effects on oak forests of different origins. They also showed that soil quality was strongly affected by aboveground biomass (AGB), the tree Shannon-Wiener index (TH'), and available potassium (AK).