Research Progress of Soil Factors Affecting the Quality of Chinese Medicinal Materials

The paper summarized the effects of soil on the quality of Chinese medicinal materials from the aspects of physical,chemical and biological properties of soil,in order to provide a reference for further research on the internal relationship between soil factors and the quality of Chinese medicinal materials,and to provide a theoretical basis for the cultivation and quality improvement of Chinese medicinal materials.

Species diversity and its relation with soil factors under different site conditions in a desert-oasis ecotone

Vegetation and soil surveys were conducted under different site conditions in 2007-2011 to study species diversity using richness, evenness and diversity indices, in the middle portion of the Heihe River Basin. The relationship between species distribution and soil environmental factors was also studied by Canonical Correspondence Analysis （CCA）. Results show that vegetation coverage and species diversity were the highest in the interdune lowland, and the lowest in the mobile dime. Results of the Hill＇s index （di- versity ordering） shows that species diversity is reduced along decreasing soil water content, and the order of species diversity was interdune lowland, flat slope, fixed dune, semifixed dune and mobile dune. The influence degree of soil factors on vegetation dis- tribution was soil water content 〉 pH 〉 total K 〉 organic matter 〉 available N 〉 total N 〉 available K 〉 total P 〉 saline content 〉 available P. Soil water content and pH were important factors significantly affecting spatial distribution difference of vegetation, the environmental explanation was 98%.

Variation Characteristics of Root Traits of Different Alfalfa Cultivars under Saline-Alkaline Stress and their Relationship with Soil Environmental Factors

Soil salinization is the main factor that threatens the growth and development of plants and limits the increase of yield.It is of great significance to study the key soil environmental factors affecting plant root traits to reveal the adaptation strategies of plants to saline-alkaline-stressed soil environments.In this study,the root biomass,root morphological parameters and root mineral nutrient content of two alfalfa cultivars with different sensitivities to alkaline stress were analyzed with black soil as the control group and the mixed saline-alkaline soil with a ratio of 7:3 between black soil and saline-alkaline soil as the saline-alkaline treatment group.At the same time,the correlation analysis of soil salinity indexes,soil nutrient indexes and the activities of key enzymes involved in soil carbon,nitrogen and phosphorus cycles was carried out.The results showed that compared with the control group,the pH,EC,and urease(URE)of the soil surrounding the roots of two alfalfa cultivars were significantly increased,while soil total nitrogen(TN),total phosphorus(TP),organic carbon(SOC),andα-glucosidase activity(AGC)were significantly decreased under saline-alkaline stress.There was no significant difference in root biomass and root morphological parameters of saline-alkaline tolerant cultivar GN under saline-alkaline stress.The number of root tips(RT),root surface area(RS)and root volume(RV)of AG were reduced by 61.16%,44.54%,and 45.31%,respectively,compared with control group.The ratios of K^(+)/Na^(+),Ca^(2+)/Na^(+)and Mg^(2+)/Na^(+)of GN were significantly higher than those of AG(p<0.05).The root fresh weight(RFW)and dry weight(RDW),root length(RL),RV and RT of alfalfa were positively regulated by soil SOC and TN,but negatively regulated by soil pH,EC,and URE(p<0.01).Root Ca^(2+)/Na+ratio was significantly positively correlated with soil TN,TP and SOC(p<0.01).The absorption of Mg and Ca ions in roots is significantly negatively regulated by soilβ-glucosidase activity(BGC)and acid phosphatase activity(APC)(p<0.05).This study improved knowledge of the relationship between root traits and soil environmental factors and offered a theoretical framework for elucidating how plant roots adapt to saline-alkaline stressed soil environments.

Assessment of soil erosion in the Irga watershed on the eastern edge of the Chota Nagpur Plateau,India

Human activities to improve the quality of life have accelerated the natural rate of soil erosion.In turn,these natural disasters have taken a great impact on humans.Human activities,particularly the conversion of vegetated land into agricultural land and built-up area,stand out as primary contributors to soil erosion.The present study investigated the risk of soil erosion in the Irga watershed located on the eastern fringe of the Chota Nagpur Plateau in Jharkhand,India,which is dominated by sandy loam and sandy clay loam soil with low soil organic carbon(SOC)content.The study used the Revised Universal Soil Loss Equation(RUSLE)and Geographical Information System(GIS)technique to determine the rate of soil erosion.The five parameters(rainfall-runoff erosivity(R)factor,soil erodibility(K)factor,slope length and steepness(LS)factor,cover-management(C)factor,and support practice(P)factor)of the RUSLE were applied to present a more accurate distribution characteristic of soil erosion in the Irga watershed.The result shows that the R factor is positively correlated with rainfall and follows the same distribution pattern as the rainfall.The K factor values in the northern part of the study area are relatively low,while they are relatively high in the southern part.The mean value of the LS factor is 2.74,which is low due to the flat terrain of the Irga watershed.There is a negative linear correlation between Normalized Difference Vegetation Index(NDVI)and the C factor,and the high values of the C factor are observed in places with low NDVI.The mean value of the P factor is 0.210,with a range from 0.000 to 1.000.After calculating all parameters,we obtained the average soil erosion rate of 1.43 t/(hm^(2)•a),with the highest rate reaching as high as 32.71 t/(hm^(2)•a).Therefore,the study area faces a low risk of soil erosion.However,preventative measures are essential to avoid future damage to productive and constructive activities caused by soil erosion.This study also identifies the spatial distribution of soil erosion rate,which will help policy-makers to implement targeted soil erosion control measures.

Exclusion effects on vegetation characteristics and their correlation to soil factors in the semi-arid rangeland of Mu Us Sandland,China

Exclusion has been applied as a main measure for re-vegetation all over the world.This paper,by comparing the results of year-round exclusion,seasonal exclusion,and non-exclusion,quantified the vegetation variations under three different exclusion measures and their correlation to soil factors.The analysis results for community species component and plant diversity using multi-response permutation procedures(MRPPs)showed that exclusion did change the species com ponent and increase plant diversity remarkably,while the period of exclusion had no significant influence on these two community features.The indicator species analysis and calculation of similarity indices indicated that community for year-round exclusion were becoming xerophytization and unpalatability,and showed highly spatial heterogeneity of plant species distribution,whereas community for seasonal exclusion was under stable non-equilibrium condition.Detrended correspondence analysis(DCA)and detrend canonical correspondence analysis(DCCA)results of relationship between plant species and soil variables demonstrated that soil moisture was a controlling factor for plant species component,microbiotic soil crust cover,soil organic matter,and soil bulk density had significant effects on soil moisture,among which microbiotic soil crust was a leading factor owing to its limitation to rainfall infiltration on the one hand,and its constraints to entrance of herbaceous seeds into soil or to germination of soil seeds on the other hand.As a result of long-term removal of animal grazing,crust kept intact in year-round exclusion community,which was a main reason of community xerophytization.It was also obvious from ordination results that some important environmental factors,such as tempo-spatial change of rainfall and corresponding tempo-spatial change of soil moisture,were neglected during direct gradient analysis.In addition,biodiversity was close related to soil nutrients as well as to soil moisture condition(soil water content and crust cover),and it had positive relation to available N,and negative relation to available P.Higher soil N had advantage to non-leguminous plants growth on nutrition-poor sand land definitely.The impact of P to community component was unclear and should be studied from plant physiology.Further researches on nonequilibrium theory in semi-arid rangeland will provide a sci-entific and flexible animal development paradigm for being implementing livestock fen-raising and grazing-forbidden policies in China.

Distribution patterns of plant communities and their associations with environmental soil factors on the eastern shore of Lake Taihu,China

Introduction:Plant communities and soil factors might interact with each other in different temporal and spatial scales,which can influence the patterns and processes of the wetland ecosystem.To get a better understanding of the distribution of plants in wetlands and analyze their associations with environmental soil factors,the structure and types of plant communities in the eastern shore area of Lake Taihu were analyzed by two-way indicator species analysis and canonical correspondence analysis(CCA)ordination.The spatial distribution patterns of vegetation and the main factors affecting the distributions were investigated.Outcomes:Sixty-six sampling sites were selected to obtain vegetation species and soil environmental factor data.Results showed that 22 species from the 66 sites could be divided into seven communities:I:Arundo donax;II:A.donax+Phragmites australis;III:Zizania latifolia+Typha orientalis;IV:P.australis+Alternanthera philoxeroides+Polygonum hydropiper;V:P.australis;VI:P.australis+Humulus scandens;and VII:Erigeron acer+Ipomoea batatas+Rumex acetosa.Plant species and soil factors in the CCA analysis showed that I.batatas,E.acer,Chenopodium album,Polygonum lapathifolium,and Acalypha australis were mainly affected by pH,whereas Echinochloa crus-galli,Setaria viridis,and H.scandens were mainly affected by soil total phosphorus.Mentha canadensis and A.donax were mainly affected by soil conductivity,A.philoxeroides was mainly affected by soil organic matter and,Z.latifolia,Metaplexis japonica and P.hydropiper were mainly affected by available phosphorus.Conclusion:These results indicated that different plants adapted to different soil environmental factors and provided basic information on the diversity of Lake Taihu wetland vegetation.

Identification of pakchoi cultivars with low cadmium accumulation and soil factors that affect their cadmium uptake and translocation

The selection and use of low-Cd-accumulating cultivar （LCAC） has been proposed as one of the promising approaches in minimizing the entry of Cd in the human food chain. This study suggests a screening criterion of LCACs focusing on food safety. Pot culture and plot experiments were conducted to screen out LCACs from 35 pakchoi cultivars and to identify the crucial soil factors that affect Cd accumulation in LCACs. Results of the pot culture experiment showed that shoot Cd concentrations under the three Cd treatments significantly varied across cultivars. Two cultivars, Hualv 2 and Huajun 2, were identified as LCACs because their shoot Cd concentrations were lower than 0.2 mg. kg-1 under low Cd treatment and high Cd exposure did not affect the biomass of their shoots. The plot experiment further confirmed the consistency and genotypic stability of the low-Cd- accumulating traits of the two LCACs under various soil conditions. Results also showed that soil phosphorus availability was the most important soil factor in the Cd accumulation of pakchoi, which related negatively not only to Cd uptake by root but also to Cd translocation from root to shoot. The total Cd accumulation and translocation rates were lower in the LCACs than in the high-Cd cultivar, suggesting that Cd accumulation in different cultivars is associated with the Cd uptake by root as well as translocation from root to shoot. This study proves the feasibility of the application of the LCAC strategy in pakchoi cultivation to cope with Cd contamination in agricultural soils.

Rhizosphere Soil Fungal Diversity and Soil Physicochemical Properties of Different Vegetations in Tundra of Changbai Mountain

By studying the diversity and community structure of rhizosphere soil fungi of different plants in the tundra on the northern slope of Changbai Mountain, it provides theoretical support for the restoration of environmental degradation and in-depth study of fungal diversity in the tundra of Changbai Mountain. High-throughput sequencing technology was used to determine the ITS1 region of fungal amplicons, so as to analyze the diversity of fungal communities in the rhizosphere soil of six plants in the tundra of Changbai Mountain, and to analyze the correlation between the environment and the diversity and richness of fungal communities in combination with relevant soil physical and chemical factors. The diversity and richness of fungal community in the rhizosphere soil of six plants in Changbai Mountain tundra were different. The Simpson and Shannon indexes of Saxifraga stolonifera Curt were the highest, and the richness of fungal community in Dryas octopetala was the highest. The analysis of fungal community composition showed that the fungal colonies in plant rhizosphere soil samples mainly belonged to Ascomycota and Basidiomycota, which were the main dominant phyla. Mortierella, Fusarium and Sordariomycetes are common fungal genera in the rhizosphere soil of six plants, but their abundances are different among different plants. Water content was negatively correlated with fungal diversity, and TP was positively correlated with fungal community diversity. There were some differences in the composition and diversity of rhizosphere soil fungal communities of six plants in Changbai Mountain tundra. Ascomycota and Basidiomycota were the main soil fungal phyla in the rhizosphere of six plants in Changbai Mountain tundra. The results could provide theoretical guidance for ecological protection of Changbai Mountain tundra.

Environmental factors affecting growth of grasses，herbs and woody plants on a sanitary landfill

The present study aims at studying relationships between various environmental factors andplant performance on a completed sanitary landfill. Three sites were chosen for comparison: an on-sitelow landfill gas region with a rich vegetation growth (Site L) , an on-site high landfill gas region with apoor vegetation growth (Site H), an off site control region (Site N) which located close to the GinDrinkers' Bay landfill. In Site H, where the levels of methane and carbon dioxide were higher, growth oftrees, shrubs and climbing plants are adversely affected, but not herbs and grasses. Analysis of correla-tion coefficient indicated that carbon dioxide and methane showed a negative correlation with the growth oftrees and shrubs. In Site H, the higher levels of conductivity, Kjeldah-N, Ammonium-N, and variousheavy metals, such as Mn were also exerted their adverse effect on plant growth. Trees tolerant to land-fill gas , e. g. Acacia confusa . would be a better choice for planting on sanitary landfills , in addition to theuse of shallow-rooted trees. Grasses and herbs are less susceptible to landfill gas due to their shallow-rootsystems. Hydroseeding of grasses would ensure a better plant coverage in areas with a moderate level oflandfill gas. Installation of a ventilation system might be needed for areas with a high level of landfill gas.

Influence of topography,soil properties and plant community on the biomass of Abies georgei var.smithii seedlings in Southeast Tibet

Biomass of seedlings at different developing stages of growth is important information for studying the response of species to site conditions.The objectives of this study was to explore the distribution characteristics of AGB(above-ground biomass)and BGB(below-ground biomass)of Abies georgei var.smithii seedlings of different ages,and investigate the effects of topography(slope aspect,altitude),plant community characteristics(crown density,species diversity,etc.),and soil properties(soil physical and chemical properties)on the biomass and its allocation.Seedlings in five age classes(1–2,3–4,5–6,7–8,and 9–10 years old)were collected by full excavation from 6 elevations(3800 m,3900 m,4000 m,4100 m,4200 m,4300 m)on the north and south slopes of Sejila Mountain in Tibet.15seedlings of each age class were investigated at one altitude.The individual effects of seedling age(SA)and the interaction effects of SA,slope aspect(SL),and elevation(EG),namely,SL×EG,SL×SA,EG×SA,and SL×EG×SA,had significant effects on the AGB of the seedlings(p<0.05),whereas BGB was only significantly affected by SA(p<0.001).The AGB and BGB of the seedlings showed a binomial growth trend with the increase in seedling age,and had an allometric relationship at different elevations,α(allometric exponential)varied from 0.913 to 1.046 in the northern slope,and from 1.004 to 1.268 in the southern slope.The biomass of seedlings on the northern slope was remarkably affected by stand factors,with a contribution rate of 47.8%,whereas that on the southern slope was considerably affected by soil factors with a contribution rate of 53.2%.The results showed that age was the most important factor affecting seedling biomass.The allometric pattern of seedling biomass was relatively stable,but in a highaltitude habitat,A.georgei var.smithii seedlings increased the input of BGB.Understanding seedling biomass allocation and its influencing factors is useful for evaluating plants’ability to acquire resources and survival strategies for adaptation to the environment in Tibet Plateau.

Graphene oxide influences bacterial community and soil environments of Cd-polluted Haplic Cambisols in Northeast China

Graphene oxide(GO),a carbon nanomaterial that is widely used in the environment and other industries,may pose potential risks to ecosystems,especially the soil ecosystem.Some soils in Northeast China are frequently polluted with cadmium(Cd) metal.However,there is no study on the influence of GO on the Cd-contaminated soil microbial community and soil chemical properties.In this study,Cd(100 mg kg^(-1))-polluted soils were treated with different concentrations of GO(0,25,50,150,250,and 500 mg L^(-1),expressed as T1,T2,T3,T4,T5,and T6,respectively) for 40 days.The treatment without Cd pollution and GO served as the control(CK).Then,we investigated the influence of the GO concentrations on the bacterial community and chemical properties of Cd-polluted Haplic Cambisols,the zonal soil in Northeast China.After GO addition,the richness and diversity indexes of the bacterial community in Cd-contaminated Haplic Cambisols initially increased by 0.05-33.92% at 25 mg L^(-1),then decreased by0.07-2.37% at 50 mg L^(-1),and then increased by 0.01-24.37%within 500 mg L^(-1) again.The species and abundance of bacteria varied with GO concentration,and GO significantly increased bacterial growth at 25 and 250 mg L^(-1).GO treatments influenced the bacterial community structure,and the order of similarity of the bacterial community structure was as follows:T4=T5> T1=T6> T2> T3> CK.Proteobacteria and Acidobacteria were the dominant bacteria,accounting for 36.0% and 26.2%,respectively,of soil bacteria.Different GO treatments also significantly affected the metabolic function of bacteria and further influenced the diversity of the bacterial community structure by affecting several key soil chemical properties:soil pH,organic matter and available potassium,phosphorus,and cadmium.Our results provide a theoretical basis for scientific and comprehensive evaluation of the environmental impacts of GO on the zonal forest soils of Northeast China.

Prediction model for mercury transfer from soil to corn grain and its cross-species extrapolation

In this study the transfer characteristics of mercury（Hg） from a wide range of Chinese soils to corn grain（cultivar Zhengdan 958） were investigated. Prediction models were developed for determining the Hg bioconcentration factor（BCF） of Zhengdan 958 from soil, including the soil properties, such as p H, organic matter（OM） concentration, cation exchange capacity（CEC）, total nitrogen concentration（TN）, total phosphorus concentration（TP）, total potassium concentration（TK）, and total Hg concentration（THg）, using multiple stepwise regression analysis. These prediction models were applied to other non-model corn cultivars using a cross-species extrapolation approach. The results indicated that the soil p H was the most important factor associated with the transfer of Hg from soil to corn grain. Hg bioaccumulation in corn grain increased with the decreasing p H. No significant differences were found between two prediction models derived from different rates of Hg applied to the soil as HgCl2. The prediction models established in this study can be applied to other non-model corn cultivars and are useful for predicting Hg bioconcentration in corn grain and assessing the ecological risk of Hg in different soils.

Nitrous Oxide Evolution from Agricultural Soil: A Regression Approach

N_2O emission from soil is affected by many factors. In this study, N_2O flux, soil temperature, water content, NO_3^- and NH_4^+ concentrations were simultaneously measured in winter wheat field. N_2O flux, NO_3^- and NH_4^+ concentrations were all lognormally distributed, while water content was normally distributed. The relationship between N_2O flux and soil factors was also studied. N_2O flux was most highly correlated with soil temperature. Regression model was developed to explain the variability of N_2O emission from agricultural soil using multifactorial analysis.

Variation of Soil CO_2 Flux and Carbon Density in Three Apline Meadows

Three alpine meadows were chosen from the eastern margin of the Qilian Mountain：Polygonum viviparum meadow（P）,Stipa capillata grassland（S）and Rhododendron simsii shrub meadow（R）;LI-8100 A soil CO2 flux auto-monitoring system and lab analysis were applied to analyze the soil organic carbon density,dynamics of carbon flux,and their relationship with environmental factors.The results showed that different vegetations varied greatly in soil organic carbon density：R 〉 S 〉 P,and the soil carbon density reduced with the increasing depth;soil CO2flux：S 〉 P 〉 R,and sample plot P and S showed unimodal changes.The peak values appeared at 14：00-15：00 p.m.;soil CO2 flux was negatively correlated with near-ground air humidity and carbon content,positively correlated with soil temperature and near-ground air temperature,and showed no obvious correlation with soil moisture.

Calibrating partial factors for Danish railway embankments using probabilistic analyses

High costs are connected with upgrading railway embankments throughout Denmark using the partial factors for geotechnical design calibrated for general application. One way to reduce the costs is reliability-based calibration of the partial factors to a reasonable safety level taking into account the specific design situations and uncertainties relevant to railway embankments. A reliability-based design has been investigated, resulting in an optimal partial factor for the considered subsoil. With a stochastic soil model to simulate the undrained shear strength of soft soil deposits, the partial factor is calibrated using asymptotic sampling for the reliability assessment. The calibration shows that the partial factor can be reduced significantly compared to the value specified in the Danish National Annex to DS/EN 1997-1 （2007）, Eurocode 7.

Climate factors affect forest biomass allocation by altering soil nutrient availability and leaf traits

Biomass in forests sequesters substantial amounts of carbon;although the contribution of aboveground biomass has been extensively studied, the contribution of belowground biomass remains understudied. Investigating the forest biomass allocation is crucial for understanding the impacts of global change on carbon allocation and cycling.Moreover, the question of how climate factors affect biomass allocation in natural and planted forests remains unresolved. Here, we addressed this question by collecting data from 384 planted forests and 541 natural forests in China. We evaluated the direct and indirect effects of climate factors on the belowground biomass proportion(BGBP). The average BGBP was 31.09% in natural forests and was significantly higher(38.75%) in planted forests. Furthermore, we observed a significant decrease in BGBP with increasing temperature and precipitation. Climate factors, particularly those affecting soil factors, such as p H,strongly affected the BGBP in natural and planted forests. Based on our results, we propose that future studies should consider the effects of forest type(natural or planted) and soil factors on BGBP.

Effects of soil rock fragment content on the USLE-K factor estimating and its influencing factors

Rock fragments are an important component of soil,and their presence has a significant impact on soil erosion and sediment yield.In this paper,the effects of rock fragments in the topsoil profile(RFP)and rock fragments on the soil surface(RFS)on the soil erodibility factor(K)were assessed at a global scale.The spatial pattern of the relationship between stoniness and erodibility(RS-K)and its predominant factors were explored through correlation analysis,pattern analysis,and random forest model analysis.The results were as followings:(1)The existence of RFP increased K by 2.84%.The RFS of the mountain land and desert/Gobi reduced K by 18.7%;therefore,once the RFP and RFS were taken into account in the calculation,K was 6.98%lower.(2)The predominant factors of the effect of RFS and the joint effect of RFP and RFS were elevation and slope gradient.The predominant factors of the effect of RFP were annual average precipitation and annual average temperature.(3)In assessing and mapping soil erosion in large regions,special attention should be given to areas with large rock fragment contents,a relatively high altitude,and the presence of steep slope.If rock fragments were not taken into consideration,the mapping results of soil erosion may be biased.This article made the calculation of K more complete and accurate,thereby improving the accuracy of regional soil erosion estimation.This research was of sig-nificance for the investigation of global hydrological effects and simulation of the global soil carbon budget.

Estimation of USLE crop and management factor values for crop rotation systems in China

Soil erosion on cropland is a major source of environmental problems in China ranging from the losses of a non-renewable resource and of nutrients at the source to contamination of downstream areas. Regional soil loss assessments using the Universal Soil Loss Equation (USLE) would supply a scientiifc basis for soil conservation planning. However, a lack of in-formation on the cover and management (C) factor for cropland, one of the most important factors in the USLE, has limited accurate regional assessments in China due to the large number of crops grown and their complicated rotation systems. In this study, single crop soil loss ratios (SLRs) were col ected and quantiifed for 10 primary crops from past studies or re-ports. The mean annual C values for 88 crop rotation systems in 12 cropping system regions were estimated based on the combined effects of single crop SLRs and the percentage of annual rainfal erosivity (R) during the corresponding periods for each system. The C values in different cropping system regions were compared and discussed. The results indicated that the SLRs of the 10 primary crops ranged from 0.15 to 0.74. The mean annual C value for al 88 crop rotation systems was 0.34, with a standard deviation of 0.12. The mean C values in the single, double and triple cropping zones were 0.37, 0.36 and 0.28, respectively, and the C value in the triple zone was signiifcantly different from those in single and double zones. The C values of dryland crop systems exhibited signiifcant differences in the single and triple cropping system regions but the differences in the double regions were not signiifcant. This study is the ifrst report of the C values of crop rotation systems in China at the national scale. It wil provide necessary and practical parameters for accurately assessing regional soil losses from cropland to guide soil conservation plans and to optimize crop rotation systems.

Soil temperature modifies effects of soil biota on plant growth

Aims Plants directly and indirectly interact with many abiotic and biotic soil components.Research so far mostly focused on direct,indi-vidual abiotic or biotic effects on plant growth,but only few studies tested the indirect effects of abiotic soil factors on plant growth.therefore,we investigated how abiotic soil conditions affect plant performance,via changes induced by soil biota.Methods In a full-factorial experiment,we grew the widespread grass Dactylis glomerata either with or without soil biota and investigated the impact of soil temperature,fertility and moisture on the soil biota effects on plant growth.We measured biomass production,root traits and colonization by arbuscular mycorrhizal fungi as well as microbial respiration.Important Findings We found significant interaction effects between abiotic soil con-ditions and soil biota on plant growth for fertility,but especially for soil temperature,as an increase of 10°c significantly changed the soil biota effects on plant growth from positive to neutral.However,if tested individually,an increase in soil temperature and fertility per se positively affected plant biomass production,whereas soil biota per se did not affect overall plant growth,but both influenced root architecture.By affecting soil microbial activ-ity and root architecture,soil temperature might influence both mutualistic and pathogenic interactions between plants and soil biota.Such soil temperature effects should be considered in soil feedback studies to ensure greater transferability of results from artificial and experimental conditions to natural environmental conditions.

Adsorption behavior of antibiotic in soil environment： a critical review

Antibiotics are used widely in human and veterinary medicine, and are ubiquitous in environment matrices worldwide. Due to their consumption, excretion, and persistence, antibiotics are disseminated mostly via direct and indirect emissions such as excrements, sewage irrigation, and sludge compost and enter the soil and impact negatively the natural ecosystem of soil. Most antibiotics are amphiphilic or amphoteric and ionize. A non-polar core combined with polar functional moieties makes up numerous antibiotic molecules. Because of various molecule structures, physicochemical properties vary widely among antibiotic compounds. Sorption is an important process for the environment behaviors and fate of antibiotics in soil environment. The adsorption process has decisive role for the environmental behaviors and the ultimate fates of antibiotics in soil. Multiply physicochem- ical properties of antibiotics induce the large variations of their adsorption behaviors. In addition, factors of soil environment such as the pH, ionic strength, metal ions, and organic matter content also strongly impact the adsorption processes of antibiotics. Review about adsorption of antibiotics on soil can provide a fresh insight into understanding the antibiotic-soil interactions. Therefore, literatures about the adsorption mechanisms of antibiotics in soil environment and the effects of environment factors on adsorption behaviors of antibiotics in soil are reviewed and discussed systematically in this review.