Leguminosae are an important part of terrestrial ecosystems and play a key role in promoting soil nutrient cycling and improving soil properties.However,plant composition and species diversity change rapidly during th...Leguminosae are an important part of terrestrial ecosystems and play a key role in promoting soil nutrient cycling and improving soil properties.However,plant composition and species diversity change rapidly during the process of succession,the effect of leguminosae on soil physical-chemical and biological properties is still unclear.This study investigated the changes in the composition of plant community,vegetation characteristics,soil physical-chemical properties,and soil biological properties on five former farmlands in China,which had been abandoned for 0,5,10,18,and 30 a.Results showed that,with successional time,plant community developed from annual plants to perennial plants,the importance of Leguminosae and Asteraceae significantly increased and decreased,respectively,and the importance of grass increased and then decreased,having a maximum value after 5 a of abandonment.Plant diversity indices increased with successional time,and vegetation coverage and above-and below-ground biomass increased significantly with successional time after 5 a of abandonment.Compared with farmland,30 a of abandonment significantly increased soil nutrient content,but total and available phosphorus decreased with successional time.Changes in plant community composition and vegetation characteristics not only change soil properties and improve soil physical-chemical properties,but also regulate soil biological activity,thus affecting soil nutrient cycling.Among these,Leguminosae have the greatest influence on soil properties,and their importance values and community composition are significantly correlated with soil properties.Therefore,this research provides more scientific guidance for selecting plant species to stabilize soil ecosystem of farmland to grassland in the Loess Plateau,China.展开更多
This paper presents a comparative study of Physical-Chemical characteristics of Limestone and Basalt (from Senegalese quarries). First, chemical tests show that Basalt is richer in silica 51.59% versus 2.84% for Limes...This paper presents a comparative study of Physical-Chemical characteristics of Limestone and Basalt (from Senegalese quarries). First, chemical tests show that Basalt is richer in silica 51.59% versus 2.84% for Limestone. Basalt is made up of silica minerals and essentially carbonated minerals with a CaO percentage of 50.05%. Chemical results also show that Basalt is richer in iron 12.71% versus 0.44% for Limestone. Finally, they revealed a fire loss of 40.91% for Limestone and 2.44% for Basalt. Second, physical analysis results show that Diack Basalt has the best characteristics with a flattening coefficient of 5% between 5% and 20%;the percentage of pollutants is 0.36% less than 1%;the Los Angeles coefficient is 12.21% below 15, while Bandia Limestone gives a flattening coefficient of 3%;the Los Angeles coefficient of 40.17% and the percentage of pollutant (2.4%) well above 2%. It is noted that the percentage of Limestone pollutant is too high. These important results show the net advantage of Basalt compared to Limestone in terms of physical-chemical characteristics.展开更多
Soil salinization has adverse effects on the soil physical-chemical characteristics.However,little is known about the changes in soil salt ion concentrations and other soil physical-chemical characteristics within the...Soil salinization has adverse effects on the soil physical-chemical characteristics.However,little is known about the changes in soil salt ion concentrations and other soil physical-chemical characteristics within the Qarhan Salt Lake and at different soil depths in the surrounding areas.Here,we selected five sampling sites(S1,S2,S3,S4,and S5)alongside the Qarhan Salt Lake and in the Xidatan segment of the Kunlun Mountains to investigate the relationship among soil salt ion concentrations,soil physical-chemical characteristics,and environmental variables in April 2019.The results indicated that most sites had strongly saline and very strongly saline conditions.The main salt ions present in the soil were Na^(+),K^(+),and Cl^(-).Soil nutrients and soil microbial biomass(SMB)were significantly affected by the salinity(P<0.05).Moreover,soil salt ions(Na^(+),K^(+),Ca2+,Mg^(2+),Cl^(-),CO_(3)^(2-),SO_(4)^(2-),and HCO_(3)^(-))were positively correlated with electrical conductivity(EC)and soil water content(SWC),but negatively related to altitude and soil depth.Unlike soil salt ions,soil nutrients and SMB were positively correlated with altitude,but negatively related to EC and SWC.Moreover,soil nutrients and SMB were negatively correlated with soil salt ions.In conclusion,soil nutrients and SMB were mainly influenced by salinity,and were related to altitude,soil depth,and SWC in the areas from the Qarhan Salt Lake to the Xidatan segment.These results imply that the soil quality(mainly evaluated by soil physical-chemical characteristics)is mainly influenced by soil salt ions in the areas surrounding the Qarhan Salt Lake.Our results provide an accurate prediction of how the soil salt ions,soil nutrients,and SMB respond to the changes along a salt gradient.The underlying mechanisms controlling the soil salt ion distribution,soil nutrients,and SMB in an extremely arid desert climate playa should be studied in greater detail in the future.展开更多
Groundwater quality assessment is important to assure safe and durable water use.In semi-arid areas of Algeria,groundwater represents the main water resource for drinking water supply of the rural population as well a...Groundwater quality assessment is important to assure safe and durable water use.In semi-arid areas of Algeria,groundwater represents the main water resource for drinking water supply of the rural population as well as for irrigation of agricultural lands.Groundwater samples from wells and springs were collected from the Gargaat Tarf and Annk Djemel sub-watersheds of the Oum El Bouaghi,Algeria,and were analyzed and compared with the World Health Organization(WHO)standards.Results showed that most of the measured physical and chemical parameters exceeded the quality limits according to the WHO standards.Groundwater had a slightly alkaline water pH(7.00-7.79),electrical conductivity>1500μS/cm,chloride>500 mg/L,calcium>250 mg/L,and magnesium>155 mg/L.Water quality index(WQI)results showed that 68%of the area had excellent water quality,24%of the samples fell into good category,and only 8%were of poor quality and unsuitable for human consumption.Six wells in the area showed bacterial contamination.Total coliforms(453.9(±180.3)CFU(colony-forming units)/100 mL),fecal coliforms(243.2(±99.2)CFU/100 mL),and fecal streptococci(77.9(±32.0)CFU/100 mL)loads were above the standard limits set by the WHO.These results confirmed that water resources in the study area were strongly influenced by anthropogenic activities and were not recommended for consumption as drinking water.展开更多
One of the goals of grazing management in the desert steppe is to improve its ecosystem.However,relatively little is known about soil microbe communities in the desert steppe ecosystem under grazing management.In this...One of the goals of grazing management in the desert steppe is to improve its ecosystem.However,relatively little is known about soil microbe communities in the desert steppe ecosystem under grazing management.In this study,we investigated the diversity and aboveground biomass of Caragana korshinskii Kom.shrub communities in long-term fencing and grazing areas,combined with an analysis of soil physical-chemical properties and genomics,with the aim of understanding how fence management affects plant-soil-microbial inter-relationships in the desert steppe,China.The results showed that fence management(exclosure)increased plant diversity and aboveground biomass in C.korshinskii shrub area and effectively enhanced soil organic carbon(233.94%),available nitrogen(87.77%),and available phosphorus(53.67%)contents.As well,the Shannon indices of soil bacteria and fungi were greater in the fenced plot.Plant-soil changes profoundly affected the alpha-and beta-diversity of soil bacteria.Fence management also altered the soil microbial community structure,significantly increasing the relative abundances of Acidobacteriota(5.31%-8.99%),Chloroflexi(3.99%-5.58%),and Glomeromycota(1.37%-3.28%).The soil bacterial-fungal co-occurrence networks under fence management had higher complexity and connectivity.Based on functional predictions,fence management significantly increased the relative abundance of bacteria with nitrification and nitrate reduction functions and decreased the relative abundance of bacteria with nitrate and nitrite respiration functions.The relative abundances of ecologically functional fungi with arbuscular mycorrhizal fungi,ectomycorrhizal fungi,and saprotrophs also significantly increased under fence management.In addition,the differential functional groups of bacteria and fungi were closely related to plant-soil changes.The results of this study have significant positive implications for the ecological restoration and reconstruction of dry desert steppe and similar areas.展开更多
The resorption of nutrients from senescent leaves allows plants to conserve and recycle nutrients. To explore the adaptation strategies of desert plants to nutrient-limited environments, we selected four typical deser...The resorption of nutrients from senescent leaves allows plants to conserve and recycle nutrients. To explore the adaptation strategies of desert plants to nutrient-limited environments, we selected four typical desert plants(Populus euphratica Oliv., Tamarix ramosissima Ledeb., Glycyrrhiza inflata Batal., and Alhagi camelorum Fisch.) growing in the desert area of the northern margin of the Tarim Basin,China. The contents of nitrogen(N), phosphorus(P), potassium(K), calcium(Ca), magnesium(Mg), and Ferrum(Fe) in the leaves of these four typical desert plants and their resorption characteristics were analyzed. The relationship of nutrient resorption efficiency with leaf functional traits and soil physical-chemical properties in two different habitats(saline-alkali land and sandy land) was discussed.The results showed that the four plants resorbed most of the elements. Ca was enriched in the leaves of P.euphratica, G. inflate, and A. camelorum;Mg was enriched in the leaves of G. inflata;and Fe was enriched in the leaves of the four plants. The results of the redundancy analysis showed that leaf thickness, soil electrical conductivity, and soil P content were the major factors affecting the nutrient resorption efficiency of the four plants. Leaf thickness was negatively correlated with N resorption efficiency(NRE),P resorption efficiency, and Fe resorption efficiency;soil electrical conductivity was positively correlated with the resorption efficiency of most elements;and soil P content was negatively correlated with the resorption efficiency of most elements in the plant leaves. The results showed that soil physical-chemical properties and soil nutrient contents had an important impact on the nutrient resorption of plant leaves.The same species growing in different habitats also differed in their resorption of different elements. The soil environment of plants and the biological characteristics of plant leaves affected the resorption of nutrient elements in different plants. The purpose of this study is to provide small-scale data support for the protection of ecosystems in nutrient-deficient areas by studying leaf functional strategies and nutrient conservation mechanisms of several typical desert plants.展开更多
The Loess Plateau,located in Gansu Province,is an important energy base in China because most of the oil and gas resources are distributed in Gansu Province.In the last 40 a,ecological environment in this region has b...The Loess Plateau,located in Gansu Province,is an important energy base in China because most of the oil and gas resources are distributed in Gansu Province.In the last 40 a,ecological environment in this region has been extremely destroyed due to the over-exploitation of crude-oil resources.Remediation of crude-oil contaminated soil in this area remains to be a challenging task.In this study,in order to elucidate the effects of organic compost and biochar on phytoremediation of crude-oil contaminated soil(20 g/kg)by Calendula officinalis,we designed five treatments,i.e.,natural attenuation(CK),planted C.officinalis only(P),planted C.officinalis with biochar amendment(PB),planted C.officinalis with organic compost amendment(PC),and planted C.officinalis with co-amendment of biochar and organic compost(PBC).After 152 d of cultivation,total petroleum hydrocarbons(TPH)removal rates of CK,P,PB,PC and PBC were 6.36%,50.08%,39.58%,73.10%and 59.87%,respectively.Shoot and root dry weights of C.officinalis significantly increased by 172.31%and 80.96%under PC and 311.61%and 145.43%under PBC,respectively as compared with P(P<0.05).Total chlorophyll contents in leaves of C.officinalis under P,PC and PBC significantly increased by 77.36%,125.50%and 79.80%,respectively(P<0.05)as compared with PB.Physical-chemical characteristics and enzymatic activity of soil in different treatments were also assessed.The highest total N,total P,available N,available P and SOM(soil organic matter)occurred in PC,followed by PBC(P<0.05).C.officinalis rhizospheric soil dehydrogenase(DHA)and polyphenol oxidase(PPO)activities in PB were lower than those of other treatments(P<0.05).The values of ACE(abundance-based coverage estimators)and Chao 1 indices for rhizospheric bacteria were the highest under PC followed by PBC,P,PB and CK(P<0.05).However,the Shannon index for bacteria was the highest under PC and PBC,followed by P,PB and CK(P<0.05).In terms of soil microbial community composition,Proteiniphilum,Immundisolibacteraceae and Solimonadaceae were relatively more abundant under PC and PBC.Relative abundances of Pseudallescheria,Ochroconis,Fusarium,Sarocladium,Podospora,Apodus,Pyrenochaetopsis and Schizothecium under PC and PBC were higher,while relative abundances of Gliomastix,Aspergillus and Alternaria were lower under PC and PBC.As per the nonmetric multidimensional scaling(NMDS)analysis,application of organic compost significantly promoted soil N and P contents,shoot length,root vitality,chlorophyll ratio,total chlorophyll,abundance and diversity of rhizospheric soil microbial community in C.officinalis.A high p H value and lower soil N and P contents induced by biochar,altered C.officinalis rhizospheric soil microbial community composition,which might have restrained its phytoremediation efficiency.The results suggest that organic compost-assisted C.officinalis phytoremediation for crude-oil contaminated soil was highly effective in the Loess Plateau,China.展开更多
This study aimed to investigate the interaction between regions with different climatic conditions(arid vs. semi-arid) and management(protected vs. unprotected) on the turnover and nestedness of vegetation in relation...This study aimed to investigate the interaction between regions with different climatic conditions(arid vs. semi-arid) and management(protected vs. unprotected) on the turnover and nestedness of vegetation in relation to physical, chemical and biological properties of soils in the Ilam Province of Iran. In each of the two regions, we sampled 8 sites(4 managed and 4 unmanaged sites) within each of which we established 4 circular plots(1000 m^2) that were used to investigate woody species, while two micro-plots(1 m×1 m) were established in each 1000-m^2 plot to analyze herbaceous species. In each sample unit, we also extracted three soil samples(0–20 cm depth) for measuring soil properties. The results indicated that the interaction between region and conservational management significantly affected the percent of canopy cover of Persian oak(Quercus brantii Linddl), soil respiration, substrate-induced respiration, as well as beta and gamma diversities and turnover of plant species. The percent of oak canopy cover was positively correlated with soil silt, electrical conductivity, available potassium, and alpha diversity, whereas it was negatively correlated with plant turnover. In addition, plant turnover was positively related to available phosphorus, while nestedness of species was positively related to organic carbon and total nitrogen. According to these results, we concluded that physical, chemical, and biological characteristics of limited ecological niche generally influenced plant diversity. Also, this study demonstrated the major contribution of the beta diversity on gamma diversity, especially in semi-arid region, because of the higher heterogeneity of vegetation in this area.展开更多
In arid desert regions of northwestern China, reclamation and subsequent irrigated cultivation have become effective ways to prevent desertification, expand arable croplands, and develop sustainable agricultural produ...In arid desert regions of northwestern China, reclamation and subsequent irrigated cultivation have become effective ways to prevent desertification, expand arable croplands, and develop sustainable agricultural production. Improvement in soil texture and fertility is crucial to high soil quality and stable crop yield. However, knowledge on the long-term effects of the conversion of desert lands into arable croplands is very limited. To address this problem, we conducted this study in an arid desert region of northwestern China to understand the changes in soil physical-chemical properties after 0, 2, 5, 10, 17, and 24 years of cultivation. Our results showed that silt and clay contents at the 17-year-old sites increased 17.5 and 152.3 folds, respectively, compared with that at the 0-year-old sites. The soil aggregate size fraction and its stability exhibited an exponential growth trend with increasing cultivation ages, but no significant change was found for the proportion of soil macroaggregates(>5.00 mm) during the 17 years of cultivation. The soil organic carbon(SOC) content at the 24-year-old sites was 6.86 g/kg and increased 8.8 folds compared with that at the 0-year-old sites. The total(or available) nitrogen, phosphorus, and potassium contents showed significant increasing trends and reached higher values after 17(or 24) years of cultivation. Changes in soil physical-chemical properties successively experienced slow, rapid, and stable development stages, but some key properties(such as soil aggregate stability and SOC) were still too low to meet the sustainable agricultural production. The results of this long-term study indicated that reasonable agricultural management, such as expanding no-tillage land area, returning straw to the fields, applying organic fertilizer, reducing chemical fertilizer application, and carrying out soil testing for formula fertilization, is urgently needed in arid desert regions.展开更多
Disturbance by rodents alters the morphologies and nutrients of plants as well as the physical-chemical properties of the soils.Changes in plants are considered to be mechanisms of defense against the disturbance by r...Disturbance by rodents alters the morphologies and nutrients of plants as well as the physical-chemical properties of the soils.Changes in plants are considered to be mechanisms of defense against the disturbance by rodents.Rodents gnaw on the assimilating branches of Haloxylon ammodendron(CA Mey.)Bunge and burrow under the bushes in the desert ecosystems of Xinjiang,China.However,eco-physiological responses of different age groups of H.ammodendron to the disturbance by rodents are not well understood.In this study,soil physical-chemical properties under the shrubs and the above-ground morphological,physiological and biochemical features of assimilating branches of H.ammodendron of different age groups(i.e.,young,30−100 cm;middle-aged,100−200 cm;and mature,>200 cm)in burrowed and non-burrowed(control)areas were studied in 2018.We found that disturbance by rodents significantly increased the crown width and total branching rates of young and middle-aged H.ammodendron.Photosynthetic pigment contents of assimilating branches of H.ammodendron were significantly reduced under the disturbance by rodents.In term of plant nutrients,the main differences among different age groups of H.ammodendron under the disturbance by rodents occurred in the total soluble sugar and reducing sugar contents that decreased in young plants,increased in middle-aged plants,and did not affect in mature plants.Crude protein and phosphorus contents significantly increased,while crude fiber and calcium contents significantly decreased in young plants.Crude fat and calcium contents significantly decreased in middle-aged plants.Soil organic matter(SOM),total nitrogen(TN),available nitrogen(AN)and available potassium(AK)contents in the topsoil(0–20 cm),which are conducive to forming''fertile islands'',also increased under the disturbance by rodents.In particular,soil AN and AK were the major factors affecting the above-ground morphological characteristics of H.ammodendron in burrowed areas.Overall,the response and defense strategies of H.ammodendron to the disturbance by rodents differed among different age groups,and the effect of the disturbance by rodents on H.ammodendron gradually weakened with the increasing plant age.展开更多
Background:There is substantial evidence that Eucalyptus for nitrogen(N)absorption and increasing the growth benefit from the introduction of N-fixing species,but the underlying mechanisms for microbially mediated soi...Background:There is substantial evidence that Eucalyptus for nitrogen(N)absorption and increasing the growth benefit from the introduction of N-fixing species,but the underlying mechanisms for microbially mediated soil N cycling remains unclear.Methods:We investigated the changes of soil pH,soil water content(SWC),soil organic carbon(SOC),total N(TN),inorganic N(NH_(4)^(+)-N and NO_(3)^(-)-N),microbial biomass and three N-degrading enzyme activities as well as the biomass and N productivity of Eucalyptus between a pure Eucalyptus urophylla×grandis plantation(PP)and a mixed Dalbergia odorifera and Eucalyptus plantation(MP)in Guangxi Zhuang Autonomous Region,China.Results:Compared with the PP site,soil pH,SWC,SOC and TN in both seasons were significantly higher at the MP site,which in turn enhanced microbial biomass and the activities of soil N-degrading enzymes.The stimulated microbial activity at the MP site likely accelerate soil N mineralization,providing more available N(NH_(4)^(+)-N in both seasons and NO_(3)^(-)-N in the wet-hot season)for Eucalyptus absorption.Overall,the N productivity of Eucalyptus at the MP site was increased by 19.7% and 21.9%,promoting the biomass increases of 15.1% and 19.2% in the drycold season and wet-hot season,respectively.Conclusion:Our results reveal the importance of microbially mediated soil N cycling in the N absorption on Eucalyptus.Introduction of D.odorifera enhances Eucalyptus biomass and N productivity,improve soil N availability and increased soil C and N concentration,which hence can be considered to be an effective sustainable management option of Eucalyptus plantations.展开更多
A 1-year baseline survey was conducted in north-western China to evaluate the ecological restoration quality of grain for green(GFG)using soil ciliate communities.The aims of this study were focused on analyzing the c...A 1-year baseline survey was conducted in north-western China to evaluate the ecological restoration quality of grain for green(GFG)using soil ciliate communities.The aims of this study were focused on analyzing the changes of soil ciliate communities in four plots(A,GFG for 15 years;B,GFG for 13 years;C,layland;D,cultivated land)for GFG environmental assessment.Simultaneously we studied the effects of vegetation communities and physical-chemical variables with GFG changes on soil ciliates.A total of 114 species of ciliates were identified among the four sample sites,representing 9 classes,14 orders,22 families and 37 genera.The community patterns of the soil ciliates were significantly correlated with the individual abundance of aboveground plants,soil water content,and soil porosity.The contents of total nitrogen were the main factor affecting the soil ciliate community composition.The species number,individual abundance,and diversity index of the ciliates were each in the order A>B>C>D;that is,the community composition of ciliates was complicated with the implementation of the GFG.It was shown that the succession of ciliate community shifts toward promoting the complexity with the progress of GFG.These findings demonstrate that soil ciliate communities may be used as a useful indicator to evaluate the effects of the ecological restoration quality of GFG.展开更多
According to the National Company of Supplying(CONAB)in 2017 alone,the national production of acai pulp reached 219855 t,equating to 180 million dollar(USD).Almost 85%of the weight of fruit is constituted by residual ...According to the National Company of Supplying(CONAB)in 2017 alone,the national production of acai pulp reached 219855 t,equating to 180 million dollar(USD).Almost 85%of the weight of fruit is constituted by residual biomass,even though researches have highlighted important applications for this biomass,most of it is discarded as organic waste.Thus,it is relevant to envisage in-depth studies about how to use these residues,particularly regarding the environmental impact of its target destination.Nanocrystalline cellulose(CNC)and lignin are organic derivatives obtained through the physical-chemical treatment of lignocellulosic biomass.Both are abundant and currently considered as biopolymers because of their structural characteristics and their diverse applications in food and the medical field.This work presents the mass yields achieved and the physical-chemical characteristics of the lignocellulosic derivatives extracted from the fiber of the acai berry.A statistical design was used to define the influence of process variables as temperature,reaction time and fiber size on the yield of these byproducts.A maximum yield close to 64%of type I CNC,with 45%of crystallinity degree was achieved at the minimum condition of temperature and fiber size.Additionally,through rheological analysis,it was possible to predict the nanocrystal aspect ratios,ranging from 71 to 125.The extracted lignin was rich in methoxy groups,p-coumaryl alcohol and p-coumaric acid,and its structural unit’s low state of aggregation can be an indication of low molecular weight,which envisions an appropriate use for this lignin to produce commodity chemicals.展开更多
基金supported by the Forestry Science and Technology Innovation Project of Shaanxi Province,China(SKLK2022-02-14)the Shaanxi Province Key Research and Development Program(2022SF-285)the China Postdoctoral Science Foundation(2020M683594).
文摘Leguminosae are an important part of terrestrial ecosystems and play a key role in promoting soil nutrient cycling and improving soil properties.However,plant composition and species diversity change rapidly during the process of succession,the effect of leguminosae on soil physical-chemical and biological properties is still unclear.This study investigated the changes in the composition of plant community,vegetation characteristics,soil physical-chemical properties,and soil biological properties on five former farmlands in China,which had been abandoned for 0,5,10,18,and 30 a.Results showed that,with successional time,plant community developed from annual plants to perennial plants,the importance of Leguminosae and Asteraceae significantly increased and decreased,respectively,and the importance of grass increased and then decreased,having a maximum value after 5 a of abandonment.Plant diversity indices increased with successional time,and vegetation coverage and above-and below-ground biomass increased significantly with successional time after 5 a of abandonment.Compared with farmland,30 a of abandonment significantly increased soil nutrient content,but total and available phosphorus decreased with successional time.Changes in plant community composition and vegetation characteristics not only change soil properties and improve soil physical-chemical properties,but also regulate soil biological activity,thus affecting soil nutrient cycling.Among these,Leguminosae have the greatest influence on soil properties,and their importance values and community composition are significantly correlated with soil properties.Therefore,this research provides more scientific guidance for selecting plant species to stabilize soil ecosystem of farmland to grassland in the Loess Plateau,China.
文摘This paper presents a comparative study of Physical-Chemical characteristics of Limestone and Basalt (from Senegalese quarries). First, chemical tests show that Basalt is richer in silica 51.59% versus 2.84% for Limestone. Basalt is made up of silica minerals and essentially carbonated minerals with a CaO percentage of 50.05%. Chemical results also show that Basalt is richer in iron 12.71% versus 0.44% for Limestone. Finally, they revealed a fire loss of 40.91% for Limestone and 2.44% for Basalt. Second, physical analysis results show that Diack Basalt has the best characteristics with a flattening coefficient of 5% between 5% and 20%;the percentage of pollutants is 0.36% less than 1%;the Los Angeles coefficient is 12.21% below 15, while Bandia Limestone gives a flattening coefficient of 3%;the Los Angeles coefficient of 40.17% and the percentage of pollutant (2.4%) well above 2%. It is noted that the percentage of Limestone pollutant is too high. These important results show the net advantage of Basalt compared to Limestone in terms of physical-chemical characteristics.
基金jointly supported by the National Natural Science Foundation of China(41621001,32061123006)the Fund of Ningxia Independent Innovation on Agriculture Science and Technology,China(NGSB-2021-14-04).
文摘Soil salinization has adverse effects on the soil physical-chemical characteristics.However,little is known about the changes in soil salt ion concentrations and other soil physical-chemical characteristics within the Qarhan Salt Lake and at different soil depths in the surrounding areas.Here,we selected five sampling sites(S1,S2,S3,S4,and S5)alongside the Qarhan Salt Lake and in the Xidatan segment of the Kunlun Mountains to investigate the relationship among soil salt ion concentrations,soil physical-chemical characteristics,and environmental variables in April 2019.The results indicated that most sites had strongly saline and very strongly saline conditions.The main salt ions present in the soil were Na^(+),K^(+),and Cl^(-).Soil nutrients and soil microbial biomass(SMB)were significantly affected by the salinity(P<0.05).Moreover,soil salt ions(Na^(+),K^(+),Ca2+,Mg^(2+),Cl^(-),CO_(3)^(2-),SO_(4)^(2-),and HCO_(3)^(-))were positively correlated with electrical conductivity(EC)and soil water content(SWC),but negatively related to altitude and soil depth.Unlike soil salt ions,soil nutrients and SMB were positively correlated with altitude,but negatively related to EC and SWC.Moreover,soil nutrients and SMB were negatively correlated with soil salt ions.In conclusion,soil nutrients and SMB were mainly influenced by salinity,and were related to altitude,soil depth,and SWC in the areas from the Qarhan Salt Lake to the Xidatan segment.These results imply that the soil quality(mainly evaluated by soil physical-chemical characteristics)is mainly influenced by soil salt ions in the areas surrounding the Qarhan Salt Lake.Our results provide an accurate prediction of how the soil salt ions,soil nutrients,and SMB respond to the changes along a salt gradient.The underlying mechanisms controlling the soil salt ion distribution,soil nutrients,and SMB in an extremely arid desert climate playa should be studied in greater detail in the future.
基金funding from the European Union’s Horizon 2020 Research&Innovation Programme(2211)under the Partnership for Research and Innovation in the Mediterranean Area(PRIMA)Project"SHARInG-MeD"from the Directorate-General for Scientific Research and Technological Development(DGRSDT)under the Projets de Recherche Formation-Universitaire(PRFU)Projects(D00L02UN120120230002,D01N01UN120120230005)。
文摘Groundwater quality assessment is important to assure safe and durable water use.In semi-arid areas of Algeria,groundwater represents the main water resource for drinking water supply of the rural population as well as for irrigation of agricultural lands.Groundwater samples from wells and springs were collected from the Gargaat Tarf and Annk Djemel sub-watersheds of the Oum El Bouaghi,Algeria,and were analyzed and compared with the World Health Organization(WHO)standards.Results showed that most of the measured physical and chemical parameters exceeded the quality limits according to the WHO standards.Groundwater had a slightly alkaline water pH(7.00-7.79),electrical conductivity>1500μS/cm,chloride>500 mg/L,calcium>250 mg/L,and magnesium>155 mg/L.Water quality index(WQI)results showed that 68%of the area had excellent water quality,24%of the samples fell into good category,and only 8%were of poor quality and unsuitable for human consumption.Six wells in the area showed bacterial contamination.Total coliforms(453.9(±180.3)CFU(colony-forming units)/100 mL),fecal coliforms(243.2(±99.2)CFU/100 mL),and fecal streptococci(77.9(±32.0)CFU/100 mL)loads were above the standard limits set by the WHO.These results confirmed that water resources in the study area were strongly influenced by anthropogenic activities and were not recommended for consumption as drinking water.
基金funded by the National Natural Science Foundation of China(32061123006,32360426).
文摘One of the goals of grazing management in the desert steppe is to improve its ecosystem.However,relatively little is known about soil microbe communities in the desert steppe ecosystem under grazing management.In this study,we investigated the diversity and aboveground biomass of Caragana korshinskii Kom.shrub communities in long-term fencing and grazing areas,combined with an analysis of soil physical-chemical properties and genomics,with the aim of understanding how fence management affects plant-soil-microbial inter-relationships in the desert steppe,China.The results showed that fence management(exclosure)increased plant diversity and aboveground biomass in C.korshinskii shrub area and effectively enhanced soil organic carbon(233.94%),available nitrogen(87.77%),and available phosphorus(53.67%)contents.As well,the Shannon indices of soil bacteria and fungi were greater in the fenced plot.Plant-soil changes profoundly affected the alpha-and beta-diversity of soil bacteria.Fence management also altered the soil microbial community structure,significantly increasing the relative abundances of Acidobacteriota(5.31%-8.99%),Chloroflexi(3.99%-5.58%),and Glomeromycota(1.37%-3.28%).The soil bacterial-fungal co-occurrence networks under fence management had higher complexity and connectivity.Based on functional predictions,fence management significantly increased the relative abundance of bacteria with nitrification and nitrate reduction functions and decreased the relative abundance of bacteria with nitrate and nitrite respiration functions.The relative abundances of ecologically functional fungi with arbuscular mycorrhizal fungi,ectomycorrhizal fungi,and saprotrophs also significantly increased under fence management.In addition,the differential functional groups of bacteria and fungi were closely related to plant-soil changes.The results of this study have significant positive implications for the ecological restoration and reconstruction of dry desert steppe and similar areas.
基金supported by the National Natural Science Foundation of China (32001145)。
文摘The resorption of nutrients from senescent leaves allows plants to conserve and recycle nutrients. To explore the adaptation strategies of desert plants to nutrient-limited environments, we selected four typical desert plants(Populus euphratica Oliv., Tamarix ramosissima Ledeb., Glycyrrhiza inflata Batal., and Alhagi camelorum Fisch.) growing in the desert area of the northern margin of the Tarim Basin,China. The contents of nitrogen(N), phosphorus(P), potassium(K), calcium(Ca), magnesium(Mg), and Ferrum(Fe) in the leaves of these four typical desert plants and their resorption characteristics were analyzed. The relationship of nutrient resorption efficiency with leaf functional traits and soil physical-chemical properties in two different habitats(saline-alkali land and sandy land) was discussed.The results showed that the four plants resorbed most of the elements. Ca was enriched in the leaves of P.euphratica, G. inflate, and A. camelorum;Mg was enriched in the leaves of G. inflata;and Fe was enriched in the leaves of the four plants. The results of the redundancy analysis showed that leaf thickness, soil electrical conductivity, and soil P content were the major factors affecting the nutrient resorption efficiency of the four plants. Leaf thickness was negatively correlated with N resorption efficiency(NRE),P resorption efficiency, and Fe resorption efficiency;soil electrical conductivity was positively correlated with the resorption efficiency of most elements;and soil P content was negatively correlated with the resorption efficiency of most elements in the plant leaves. The results showed that soil physical-chemical properties and soil nutrient contents had an important impact on the nutrient resorption of plant leaves.The same species growing in different habitats also differed in their resorption of different elements. The soil environment of plants and the biological characteristics of plant leaves affected the resorption of nutrient elements in different plants. The purpose of this study is to provide small-scale data support for the protection of ecosystems in nutrient-deficient areas by studying leaf functional strategies and nutrient conservation mechanisms of several typical desert plants.
基金funded by the Scientific Project of Gansu Province,China(20JR5RA548)the National Natural Science Foundation of China(31860148)+1 种基金the Natural Science Foundation of Gansu Province,China(21JR1RM333)the Doctoral Program of Longdong University,China(XYBY1909)。
文摘The Loess Plateau,located in Gansu Province,is an important energy base in China because most of the oil and gas resources are distributed in Gansu Province.In the last 40 a,ecological environment in this region has been extremely destroyed due to the over-exploitation of crude-oil resources.Remediation of crude-oil contaminated soil in this area remains to be a challenging task.In this study,in order to elucidate the effects of organic compost and biochar on phytoremediation of crude-oil contaminated soil(20 g/kg)by Calendula officinalis,we designed five treatments,i.e.,natural attenuation(CK),planted C.officinalis only(P),planted C.officinalis with biochar amendment(PB),planted C.officinalis with organic compost amendment(PC),and planted C.officinalis with co-amendment of biochar and organic compost(PBC).After 152 d of cultivation,total petroleum hydrocarbons(TPH)removal rates of CK,P,PB,PC and PBC were 6.36%,50.08%,39.58%,73.10%and 59.87%,respectively.Shoot and root dry weights of C.officinalis significantly increased by 172.31%and 80.96%under PC and 311.61%and 145.43%under PBC,respectively as compared with P(P<0.05).Total chlorophyll contents in leaves of C.officinalis under P,PC and PBC significantly increased by 77.36%,125.50%and 79.80%,respectively(P<0.05)as compared with PB.Physical-chemical characteristics and enzymatic activity of soil in different treatments were also assessed.The highest total N,total P,available N,available P and SOM(soil organic matter)occurred in PC,followed by PBC(P<0.05).C.officinalis rhizospheric soil dehydrogenase(DHA)and polyphenol oxidase(PPO)activities in PB were lower than those of other treatments(P<0.05).The values of ACE(abundance-based coverage estimators)and Chao 1 indices for rhizospheric bacteria were the highest under PC followed by PBC,P,PB and CK(P<0.05).However,the Shannon index for bacteria was the highest under PC and PBC,followed by P,PB and CK(P<0.05).In terms of soil microbial community composition,Proteiniphilum,Immundisolibacteraceae and Solimonadaceae were relatively more abundant under PC and PBC.Relative abundances of Pseudallescheria,Ochroconis,Fusarium,Sarocladium,Podospora,Apodus,Pyrenochaetopsis and Schizothecium under PC and PBC were higher,while relative abundances of Gliomastix,Aspergillus and Alternaria were lower under PC and PBC.As per the nonmetric multidimensional scaling(NMDS)analysis,application of organic compost significantly promoted soil N and P contents,shoot length,root vitality,chlorophyll ratio,total chlorophyll,abundance and diversity of rhizospheric soil microbial community in C.officinalis.A high p H value and lower soil N and P contents induced by biochar,altered C.officinalis rhizospheric soil microbial community composition,which might have restrained its phytoremediation efficiency.The results suggest that organic compost-assisted C.officinalis phytoremediation for crude-oil contaminated soil was highly effective in the Loess Plateau,China.
基金Ilam University is kindly acknowledged for its financial support for this research work
文摘This study aimed to investigate the interaction between regions with different climatic conditions(arid vs. semi-arid) and management(protected vs. unprotected) on the turnover and nestedness of vegetation in relation to physical, chemical and biological properties of soils in the Ilam Province of Iran. In each of the two regions, we sampled 8 sites(4 managed and 4 unmanaged sites) within each of which we established 4 circular plots(1000 m^2) that were used to investigate woody species, while two micro-plots(1 m×1 m) were established in each 1000-m^2 plot to analyze herbaceous species. In each sample unit, we also extracted three soil samples(0–20 cm depth) for measuring soil properties. The results indicated that the interaction between region and conservational management significantly affected the percent of canopy cover of Persian oak(Quercus brantii Linddl), soil respiration, substrate-induced respiration, as well as beta and gamma diversities and turnover of plant species. The percent of oak canopy cover was positively correlated with soil silt, electrical conductivity, available potassium, and alpha diversity, whereas it was negatively correlated with plant turnover. In addition, plant turnover was positively related to available phosphorus, while nestedness of species was positively related to organic carbon and total nitrogen. According to these results, we concluded that physical, chemical, and biological characteristics of limited ecological niche generally influenced plant diversity. Also, this study demonstrated the major contribution of the beta diversity on gamma diversity, especially in semi-arid region, because of the higher heterogeneity of vegetation in this area.
基金funded by the National Key Research and Development Project (2017YFC0504303)the Strategic Priority Research Program of Chines Academy of Science (XDA2003010301)the National Natural Science Foundation of China (41671103)。
文摘In arid desert regions of northwestern China, reclamation and subsequent irrigated cultivation have become effective ways to prevent desertification, expand arable croplands, and develop sustainable agricultural production. Improvement in soil texture and fertility is crucial to high soil quality and stable crop yield. However, knowledge on the long-term effects of the conversion of desert lands into arable croplands is very limited. To address this problem, we conducted this study in an arid desert region of northwestern China to understand the changes in soil physical-chemical properties after 0, 2, 5, 10, 17, and 24 years of cultivation. Our results showed that silt and clay contents at the 17-year-old sites increased 17.5 and 152.3 folds, respectively, compared with that at the 0-year-old sites. The soil aggregate size fraction and its stability exhibited an exponential growth trend with increasing cultivation ages, but no significant change was found for the proportion of soil macroaggregates(>5.00 mm) during the 17 years of cultivation. The soil organic carbon(SOC) content at the 24-year-old sites was 6.86 g/kg and increased 8.8 folds compared with that at the 0-year-old sites. The total(or available) nitrogen, phosphorus, and potassium contents showed significant increasing trends and reached higher values after 17(or 24) years of cultivation. Changes in soil physical-chemical properties successively experienced slow, rapid, and stable development stages, but some key properties(such as soil aggregate stability and SOC) were still too low to meet the sustainable agricultural production. The results of this long-term study indicated that reasonable agricultural management, such as expanding no-tillage land area, returning straw to the fields, applying organic fertilizer, reducing chemical fertilizer application, and carrying out soil testing for formula fertilization, is urgently needed in arid desert regions.
基金The study was funded by the National Natural Science Foundation of China(41561010,31560177)。
文摘Disturbance by rodents alters the morphologies and nutrients of plants as well as the physical-chemical properties of the soils.Changes in plants are considered to be mechanisms of defense against the disturbance by rodents.Rodents gnaw on the assimilating branches of Haloxylon ammodendron(CA Mey.)Bunge and burrow under the bushes in the desert ecosystems of Xinjiang,China.However,eco-physiological responses of different age groups of H.ammodendron to the disturbance by rodents are not well understood.In this study,soil physical-chemical properties under the shrubs and the above-ground morphological,physiological and biochemical features of assimilating branches of H.ammodendron of different age groups(i.e.,young,30−100 cm;middle-aged,100−200 cm;and mature,>200 cm)in burrowed and non-burrowed(control)areas were studied in 2018.We found that disturbance by rodents significantly increased the crown width and total branching rates of young and middle-aged H.ammodendron.Photosynthetic pigment contents of assimilating branches of H.ammodendron were significantly reduced under the disturbance by rodents.In term of plant nutrients,the main differences among different age groups of H.ammodendron under the disturbance by rodents occurred in the total soluble sugar and reducing sugar contents that decreased in young plants,increased in middle-aged plants,and did not affect in mature plants.Crude protein and phosphorus contents significantly increased,while crude fiber and calcium contents significantly decreased in young plants.Crude fat and calcium contents significantly decreased in middle-aged plants.Soil organic matter(SOM),total nitrogen(TN),available nitrogen(AN)and available potassium(AK)contents in the topsoil(0–20 cm),which are conducive to forming''fertile islands'',also increased under the disturbance by rodents.In particular,soil AN and AK were the major factors affecting the above-ground morphological characteristics of H.ammodendron in burrowed areas.Overall,the response and defense strategies of H.ammodendron to the disturbance by rodents differed among different age groups,and the effect of the disturbance by rodents on H.ammodendron gradually weakened with the increasing plant age.
基金supported by the National Natural Science Foundation of China(No.31460196 and 31870461)the Innovation Project of Guangxi Graduate Education(No.YCBZ2018012),the“Hundred Talent Program”of South China Botanical Garden at the Chinese Academy of Sciences(No.Y761031001)+1 种基金the“Young Top-notch Talent”in Pearl River talent plan of Guangdong Provinceby the Science(No.2019QN01L763).
文摘Background:There is substantial evidence that Eucalyptus for nitrogen(N)absorption and increasing the growth benefit from the introduction of N-fixing species,but the underlying mechanisms for microbially mediated soil N cycling remains unclear.Methods:We investigated the changes of soil pH,soil water content(SWC),soil organic carbon(SOC),total N(TN),inorganic N(NH_(4)^(+)-N and NO_(3)^(-)-N),microbial biomass and three N-degrading enzyme activities as well as the biomass and N productivity of Eucalyptus between a pure Eucalyptus urophylla×grandis plantation(PP)and a mixed Dalbergia odorifera and Eucalyptus plantation(MP)in Guangxi Zhuang Autonomous Region,China.Results:Compared with the PP site,soil pH,SWC,SOC and TN in both seasons were significantly higher at the MP site,which in turn enhanced microbial biomass and the activities of soil N-degrading enzymes.The stimulated microbial activity at the MP site likely accelerate soil N mineralization,providing more available N(NH_(4)^(+)-N in both seasons and NO_(3)^(-)-N in the wet-hot season)for Eucalyptus absorption.Overall,the N productivity of Eucalyptus at the MP site was increased by 19.7% and 21.9%,promoting the biomass increases of 15.1% and 19.2% in the drycold season and wet-hot season,respectively.Conclusion:Our results reveal the importance of microbially mediated soil N cycling in the N absorption on Eucalyptus.Introduction of D.odorifera enhances Eucalyptus biomass and N productivity,improve soil N availability and increased soil C and N concentration,which hence can be considered to be an effective sustainable management option of Eucalyptus plantations.
基金the National Natural Science Foundation of China(Project number:41761056,41361055,42067012).
文摘A 1-year baseline survey was conducted in north-western China to evaluate the ecological restoration quality of grain for green(GFG)using soil ciliate communities.The aims of this study were focused on analyzing the changes of soil ciliate communities in four plots(A,GFG for 15 years;B,GFG for 13 years;C,layland;D,cultivated land)for GFG environmental assessment.Simultaneously we studied the effects of vegetation communities and physical-chemical variables with GFG changes on soil ciliates.A total of 114 species of ciliates were identified among the four sample sites,representing 9 classes,14 orders,22 families and 37 genera.The community patterns of the soil ciliates were significantly correlated with the individual abundance of aboveground plants,soil water content,and soil porosity.The contents of total nitrogen were the main factor affecting the soil ciliate community composition.The species number,individual abundance,and diversity index of the ciliates were each in the order A>B>C>D;that is,the community composition of ciliates was complicated with the implementation of the GFG.It was shown that the succession of ciliate community shifts toward promoting the complexity with the progress of GFG.These findings demonstrate that soil ciliate communities may be used as a useful indicator to evaluate the effects of the ecological restoration quality of GFG.
基金support for this work by Maranhão Research Foundation(FAPEMA(No.00848/18).
文摘According to the National Company of Supplying(CONAB)in 2017 alone,the national production of acai pulp reached 219855 t,equating to 180 million dollar(USD).Almost 85%of the weight of fruit is constituted by residual biomass,even though researches have highlighted important applications for this biomass,most of it is discarded as organic waste.Thus,it is relevant to envisage in-depth studies about how to use these residues,particularly regarding the environmental impact of its target destination.Nanocrystalline cellulose(CNC)and lignin are organic derivatives obtained through the physical-chemical treatment of lignocellulosic biomass.Both are abundant and currently considered as biopolymers because of their structural characteristics and their diverse applications in food and the medical field.This work presents the mass yields achieved and the physical-chemical characteristics of the lignocellulosic derivatives extracted from the fiber of the acai berry.A statistical design was used to define the influence of process variables as temperature,reaction time and fiber size on the yield of these byproducts.A maximum yield close to 64%of type I CNC,with 45%of crystallinity degree was achieved at the minimum condition of temperature and fiber size.Additionally,through rheological analysis,it was possible to predict the nanocrystal aspect ratios,ranging from 71 to 125.The extracted lignin was rich in methoxy groups,p-coumaryl alcohol and p-coumaric acid,and its structural unit’s low state of aggregation can be an indication of low molecular weight,which envisions an appropriate use for this lignin to produce commodity chemicals.
