Deforestation is one of the most serious environmental problems facing humankind.It continues to escalate rapidly across many regions of the world,thereby deteriorating the forest soil quality.This has prompted a larg...Deforestation is one of the most serious environmental problems facing humankind.It continues to escalate rapidly across many regions of the world,thereby deteriorating the forest soil quality.This has prompted a large number of field-based studies aimed at understanding the impacts of deforestation on soil properties.However,the lack of comprehensive meta-analyses that utilized these studies has limited our deeper understanding of how different soil properties,including the soil organic carbon(SOC)pool,respond to deforestation.To address this critical knowledge gap,we conducted a meta-analysis of 144 studies to explore the impacts of deforestation on soil chemical,physical,and biological properties,with special emphasis on the long-term changes in SOC,such as concentrations,stocks,and sequestration.The results revealed that deforestation significantly decreased soil organic matter,electrical conductivity,and base saturation by 52%,50%,and 98%,respectively.While deforestation increased soil total nitrogen content and decreased available phosphorus content by 51%and 99%,respectively,it resulted in slight decreases in some chemical properties,including soil pH(1%)and base cations(1%–13%).Deforestation significantly increased bulk density by 27%and soil erosion by 47%,but significantly decreased soil aggregate stability by 39%and saturated hydraulic conductivity by 63%.Soil microbial biomass C and N concentrations and enzyme activities were significantly decreased as a consequence of deforestation.Soil biological properties were much more affected by deforestation than soil physical and chemical properties.Regarding the SOC,the land use conversion from forest to pasture significantly increased SOC concentrations,stocks,and sequestration rates(11%–13%),whereas the land use conversions from forest to both plantation and cropland significantly decreased SOC concentrations,stocks,and sequestration rates(10%–43%).This observed decline in SOC accumulations decreased with increasing years after deforestation.The SOC dynamics following deforestation were predominantly regulated by microbial biomass concentrations,dehydrogenase activity,soil erosion,saturated hydraulic conductivity,aggregate stability,as well as concentrations of total organic carbon,total nitrogen,total phosphorus and organic matter.The present meta-analytical study provides compelling evidence that deforestation can induce profound changes in soil characteristics,including soil C contents,and has significant implications for soil health sustainability and climate change mitigation.展开更多
Increasing temperatures and severe droughts threaten forest vitality globally.Prediction of forest response to climate change requires knowledge of the spatiotemporal patterns of monthly or seasonal climatic impacts o...Increasing temperatures and severe droughts threaten forest vitality globally.Prediction of forest response to climate change requires knowledge of the spatiotemporal patterns of monthly or seasonal climatic impacts on the growth of tree species,likely driven by local climatic aridity,climate trends,edaphic conditions,and the climatic adaption of tree species.The ability of tree species to cope with changing climate and the effects of environmental variables on growth trends and growth-climate relationships across diverse bioclimatic regions are still poorly understood for many species.This study investigated radial growth trends,interannual growth variability,and growth-climate sensitivity of two dominant tree species,Pinus tabulaeformis(PT)and Pinus sylvestris var.mongolica(PS),across a broad climatic gradient with a variety of soil properties in temperate Northern China.Using a network of 83 tree ring chronologies(54 for PT and 29 for PS)from 1971 to 2010,we documented that both species maintained constant growth trends at wet sites,while both displayed rapid declines at dry sites.We reported the species-specific drivers of spatial heterogeneity in growth trends,interannual growth variability,and growth-climate relationships.Calculated climatic variables and soil properties were identified as the most critical factors affecting the growth trends and growth-climate relationships.However,climatic variables play more essential roles than soil properties in determining the spatial heterogeneity of the growth-climate relationship.Lower clay content and higher soil nutrient regimes can exacerbate the moisture-related susceptibility of tree growth.Our findings highlight that soil properties emerged as important modulating factors to predict the drought vulnerability of forests in addition to climatic variables.Considering the continued climate warmingdrying trend in the future,both pines will face a more severe growth decline and increase in drought vulnerability at drier sites with lower clayed soil or higher nutrient regimes.展开更多
After landing in the Utopia Planitia,Tianwen-1 formed the deepest landing crater on Mars,approximately 40 cm deep,exposing precious information about the mechanical properties of Martian soil.We established numerical ...After landing in the Utopia Planitia,Tianwen-1 formed the deepest landing crater on Mars,approximately 40 cm deep,exposing precious information about the mechanical properties of Martian soil.We established numerical models for the plume-surface interaction(PSI)and the crater formation based on Computational Fluid Dynamics(CFD)methods and the erosion model modified from Roberts’Theory.Comparative studies of cases were conducted with different nozzle heights and soil mechanical properties.The increase in cohesion and internal friction angle leads to a decrease in erosion rate and maximum crater depth,with the cohesion having a greater impact.The influence of the nozzle height is not clear,as it interacts with the position of the Shock Diamond to jointly control the erosion process.Furthermore,we categorized the evolution of landing craters into the dispersive and the concentrated erosion modes based on the morphological characteristics.Finally,we estimated the upper limits of the Martian soil’s mechanical properties near Tianwen-1 landing site,with the cohesion ranging from 2612 to 2042 Pa and internal friction angle from 25°to 41°.展开更多
Soil pedestals have long been used as qualitative indicators of soil splash erosion.In rangelands,plant-capped pedestals,generally grass tussocks,have also been used to quantitatively estimate soil loss since the firs...Soil pedestals have long been used as qualitative indicators of soil splash erosion.In rangelands,plant-capped pedestals,generally grass tussocks,have also been used to quantitatively estimate soil loss since the first half of the twentieth century.In agricultural lands,forests,and bad-lands,stone-capped pedestals have been used as qualitative and semi-quantitative indicators of active,'extreme'erosion.Little work has been reported on using capstone pedestal data for quantifying soil loss.We postulate that three distinct capstone pedestal types may be present in any given location and that a detailed analysis of a pedestal height histogram may be used to recognize their populations.This analysis can subsequently inform if soil loss can be reliably estimated and if so,which of the existing methods using pedestal height data will provide more accurate results.The three proposed capstone pedestal types are:(1)neo-pedestals formed underneath surface stones exposed by(partial)removal of the soil surface cover;(2)endo-pedestals formed underneath stones that were buried in the soil but have been exposed by erosion;and(3)phoenix-pedestals formed underneath stones from collapsed pedestals.In the pedestal height histogram of any given location,a skew to smaller heights may indicate the existence of endo-and/or phoenix-pedestals,which may be revealed as a bi-(or tri)modal distribution when using a smaller bin size.This concept was applied to a case study where soil loss had been monitored for control plots and mulched plots during a 5-year period following wildfire in a eucalypt plantation.We measured pedestal heights and used methods to quantitatively assess soil loss from soil pedestal data in the available literature.Soil pedestal data at the end of the 5-year period under or overestimated soil loss in the control treatment,with results ranging from 60 to 115%of measured soil loss,depending on the method.It is postulated that phoenix-and endo-pedestals may be a driving factor behind the observed discrepancies.We discuss how future research may provide more insight into dominant processes,and how frequency distributions may be used to select the best methods for estimating soil loss from pedestals.展开更多
Methanotrophs,organisms that obtain oxygen by oxidizing methane,are recognized as the only known biological sink for atmospheric CH_4,and forest soil methanotrophs play crucial roles in mitigating global warming.The s...Methanotrophs,organisms that obtain oxygen by oxidizing methane,are recognized as the only known biological sink for atmospheric CH_4,and forest soil methanotrophs play crucial roles in mitigating global warming.The succession patterns of methanotrophic communities and functions in Wudalianchi volcano forest soils could provide a basis for the study of evolutionary mechanisms between soil microorganisms,the environment,and carbon cycling of temperate forest ecosystems under climate change.In this study,the characteristics and drivers of methanotrophic community structure and function of two volcanic soils at different stages of development are analyzed,including an old volcano and a new volcano,which most recently erupted 300 years and 17-19×10^(5)years ago,respectively,and a non-volcano hills as control,based on space for time substitution and Miseq sequencing and bioinformation technology.The results showed that CH_(4) fluxes were significantly higher in old-stage volcano forest soils than new-stage forest soils and non-volcano forest soils.There were significant differences in the community composition and diversity of soil methanotrophs from different volcano forest soils.Methylococcus was the dominant genus in all soil samples.Additionally,the relative abundance of Methylococcus,along with Clonothrix,Methyloglobulus,Methylomagum,Methylomonas and Methylosarcina,were the important genera responsible for the differences in methanotrophic community structure in different volcano forest soils.The relative abundance of methanotroph belonging toγ-proteobacteria was significantly higher than that belonging toα-proteobacteria(P<0.05).Chao1,Shannon and Simpson indices of soil methanotrophic community were significantly lower in new-stage volcanos and were significantly affected by bulk density,total porosity,p H,nitrate,dissolved organic carbon and dissolved organic nitrogen.There were significant differences in community structure between new-stage and old-stage volcanoes.Bulk density and p H are important soil properties contributing to the divergence of methanotrophs community structure,and changes in soil properties due to soil development time are important factors driving differences in methanotrophs communities in Wudalianchi volcanic soils.展开更多
There is considerable interest devoted to oldgrowth forests and their capacity to store carbon(C)in biomass and soil.Inventories of C stocks in old-growth forests are carried out worldwide,although there is a lack of ...There is considerable interest devoted to oldgrowth forests and their capacity to store carbon(C)in biomass and soil.Inventories of C stocks in old-growth forests are carried out worldwide,although there is a lack of information on their actual potential for C sequestration.To further understand this,soil organic carbon(SOC)was measured in one of Italy's best-preserved old-growth forests,the Sasso Fratino Integral Nature Reserve.This reserve is on the World Heritage List along with other ancient beech forests of Europe,and it is virtually untouched due to the steepness of the terrain,even before legal constraints were imposed.Although the sandstone-derived soils are often shallow,they are rich in organic matter.However,no quantification had been carried out.By systematically sampling the topsoil across the forest,we accurately determined the average amount of SOC(62.0±16.9 Mg ha^(–1))and nitrogen(4.0±1.2 Mg ha^(–1))in the top 20 cm.Using the CENTURY model,future dynamics of SOC stocks were predicted to 2050 according to two climate scenarios,A1F1 and B2,the first of high concern and the second more optimistic.The model projected an increase of 0.2 and 0.3 Mg ha^(–1)a^(–1)by 2030 under the A1F1 and B2 scenarios,respectively,suggesting that the topsoil in old-growth forests does not reach equilibrium but continues accumulating SOC.However,from 2030 to 2050,a decline in SOC accumulation is predicted,indicating SOC net loss at high altitudes under the worst-case scenario.This study confirms that soils in oldgrowth forests play a significant role in carbon sequestration.It also suggests that climate change may affect the potential of these forests to store SOC not only in the long term but also in the coming years.展开更多
Stand age is an important indicator of tree growth and life cycle,and has implications for ecological and biological processes.This study examined changes in soil microbial biomass(SMB)as well as enzyme activities of ...Stand age is an important indicator of tree growth and life cycle,and has implications for ecological and biological processes.This study examined changes in soil microbial biomass(SMB)as well as enzyme activities of different aged plantations and revealed their relationship to soil properties.SMB,microbial biomass carbon(MBC),microbial biomass nitrogen(MBN),microbial biomass phos-phorous(MBP)and enzyme activities(β-1,4-glucosidase(β-G),β-1,4-xylosidase(β-X),cellobiohydrolase(CBH),leucine aminopeptidase(LAP),β-1,4-n-acetylglucosamine(NAG)and acid phosphatase(ACP))were measured in Oro-mosia hosiei plantations of different ages.The soil qual-ity index(SQI)model assessed soil quality.SMB contents significantly decreased in young(7-year-old)and mature plantations(45-year-old)compared to middle-aged(20-year-old)plantations.Activity of soilβ-G,β-X,CBH and NAG in the 20-year-old plantations was markedly higher than in the other plantations except forβ-G,CBH and NAG in the 45-year-old plantations.Soil organic carbon(SOC),total potassium(TK),total porosity,dissolved organic carbon,nitrate nitrogen(NO_(3)--N)and non-capillary porosity were key factors affecting SMB,while soil bulk density,pH,SOC,NO_(3)--N,TK and forest litter(FL)were the main factors affecting soil enzyme activities.SQI decreased in the order:middle-aged>mature>young.The efficiency of soil organic matter conversion,the effect of nitrogen min-eralization and fixation by microorganisms,and the better efficiency of phosphorus utilization in mid-age plantations,which improves soil physical properties,better facilitates tree growth,and further improves the buffering of the soil against acidity and alkalinity.FL quality was the only soil biological factor affecting soil enzyme activity.Our findings demonstrate that different aged plantations affect soil micro-bial biomass,enzyme activity,and soil quality.展开更多
Different chemical compositions of soil organic carbon(SOC)affect its persistence and whether it signifi-cantly differs between natural forests and plantations remains unclear.By synthesizing 234 observations of SOC c...Different chemical compositions of soil organic carbon(SOC)affect its persistence and whether it signifi-cantly differs between natural forests and plantations remains unclear.By synthesizing 234 observations of SOC chemical compositions,we evaluated global patterns of concentra-tion,individual chemical composition(alkyl C,O-alkyl C,aromatic C,and carbonyl C),and their distribution even-ness.Our results indicate a notably higher SOC,a markedly larger proportion of recalcitrant alkyl C,and lower easily decomposed carbonyl C proportion in natural forests.How-ever,SOC chemical compositions were appreciably more evenly distributed in plantations.Based on the assumed con-ceptual index of SOC chemical composition evenness,we deduced that,compared to natural forests,plantations may have higher possible resistance to SOC decomposition under disturbances.In tropical regions,SOC levels,recalcitrant SOC chemical composition,and their distributed evenness were significantly higher in natural forests,indicating that SOC has higher chemical stability and possible resistance to decomposition.Climate factors had minor effects on alkyl C in forests globally,while they notably affected SOC chemi-cal composition in tropical forests.This could contribute to the differences in chemical compositions and their distrib-uted evenness between plantations and natural stands.展开更多
Soil organic carbon(SOC)affects the function of terrestrial ecosystem and plays a vital role in global carbon cycle.Yet,large uncertainty still existed regarding the changes in SOC stock and quality with forest succes...Soil organic carbon(SOC)affects the function of terrestrial ecosystem and plays a vital role in global carbon cycle.Yet,large uncertainty still existed regarding the changes in SOC stock and quality with forest succession.Here,the stock and quality of SOC at 1-m soil profile were investigated across a subalpine forest series,including shrub,deciduous broad-leaved forest,broadleaf-conifer mixed forest,middle-age coniferous forest and mature coniferous forest,which located at southeast of Tibetan Plateau.The results showed that SOC stock ranged from 9.8 to29.9 kg·m^(-2),and exhibited a hump-shaped response pattern across the forest successional series.The highest and lowest SOC stock was observed in the mixed forest and shrub forest,respectively.The SOC stock had no significant relationships with soil temperature and litter stock,but was positively correlated with wood debris stock.Meanwhile,the average percentages of polysaccharides,lignins,aromatics and aliphatics based on FTIR spectroscopy were 79.89%,0.94%,18.87%and 0.29%,respectively.Furthermore,the percentage of polysaccharides exhibited an increasing pattern across the forest successional series except for the sudden decreasing in the mixed forest,while the proportions of lignins,aromatics and aliphatics exhibited a decreasing pattern across the forest successional series except for the sudden increasing in the mixed forest.Consequently,the humification indices(HIs)were highest in the mixed forest compared to the other four successional stages,which means that the SOC quality in mixed forest was worse than other successional stages.In addition,the SOC stock,recalcitrant fractions and HIs decreased with increasing soil depth,while the polysaccharides exhibited an increasing pattern.These findings demonstrate that the mixed forest had higher SOC stock and worse SOC quality than other successional stages.The high proportion of SOC stock(66%at depth of 20-100 cm)and better SOC quality(lower HIs)indicate that deep soil have tremendous potential to store SOC and needs more attention under global chan ge.展开更多
Afforestation has an important role in biodiversity conservation and ecosystem function improvement.A meta-analysis was carried out in China,which has the largest plantation area globally,to quantify the effects of pl...Afforestation has an important role in biodiversity conservation and ecosystem function improvement.A meta-analysis was carried out in China,which has the largest plantation area globally,to quantify the effects of plantings on soil microbial diversity.The results showed that the overall effect of afforestation on soil microbial diversity was positive across the country.Random forest algorithm suggested that soil carbon was the most important factor regulating microbial diversity and the positive response was only found with new plantings on low-carbon bare lands but not on high-carbon farmlands and grasslands.In addition,afforestation with broadleaved species increased microbial diversity,whereas planting with conifers had no effect on microbial diversity.This study clarified the effects of plantings on soil microbial diversity,which has an important implication for establishing appropriate policies and practices to improve the multiple functionalities(e.g.,biodiversity conservation and climate change mitigation)during plantation establishment.展开更多
To obtain more stable spectral data for accurate quantitative analysis of multi-element,especially for the large-area in-situ elements detection of soils, we propose a method for a multielement quantitative analysis o...To obtain more stable spectral data for accurate quantitative analysis of multi-element,especially for the large-area in-situ elements detection of soils, we propose a method for a multielement quantitative analysis of soils using calibration-free laser-induced breakdown spectroscopy(CF-LIBS) based on data filtering. In this study, we analyze a standard soil sample doped with two heavy metal elements, Cu and Cd, with a specific focus on the line of Cu I324.75 nm for filtering the experimental data of multiple sample sets. Pre-and post-data filtering,the relative standard deviation for Cu decreased from 30% to 10%, The limits of detection(LOD)values for Cu and Cd decreased by 5% and 4%, respectively. Through CF-LIBS, a quantitative analysis was conducted to determine the relative content of elements in soils. Using Cu as a reference, the concentration of Cd was accurately calculated. The results show that post-data filtering, the average relative error of the Cd decreases from 11% to 5%, indicating the effectiveness of data filtering in improving the accuracy of quantitative analysis. Moreover, the content of Si, Fe and other elements can be accurately calculated using this method. To further correct the calculation, the results for Cd was used to provide a more precise calculation. This approach is of great importance for the large-area in-situ heavy metals and trace elements detection in soil, as well as for rapid and accurate quantitative analysis.展开更多
Background:Forest soils in tropical and subtropical areas store a significant amount of carbon.Recent framework to assess soil organic matter(SOM)dynamics under evolving global conditions suggest that dividing bulk SO...Background:Forest soils in tropical and subtropical areas store a significant amount of carbon.Recent framework to assess soil organic matter(SOM)dynamics under evolving global conditions suggest that dividing bulk SOM into particulate and mineral-associated organic matter(POM vs.MAOM)is a promising method for identifying how SOM contributes to reducing global warming.Soil macrofauna,earthworms,and millipedes have been found to play an important role in facilitating SOM processes.However,how these two co-existing macrofaunae impac the litter decomposition process and directly impact the formation of POM and MAOM remains unclear.Methods:Here,we set up a microcosm experiment,which consisted of 20 microcosms with four treatments earthworm and litter addition(E),millipedes and litter addition(M),earthworm,millipedes,and litter addition(E+M),and control(only litter addition)in five replicates.The soil and litter were sterilized prior to beginning the incubation experiment to remove any existing microbes.After incubating the samples for 42 days,the litte properties(mass,C,and N contents),soil physicochemical properties,as well as the C and N contents,and POM and MAOM^(13)C abundance in the 0–5 and 5–10 cm soil layers were measured.Finally,the relative influences o soil physicochemical and microbial properties on the distribution of C and N in the soil fractions were analyzed Results:The litter mass,C,and N associated with all four treatments significantly decreased after incubation especially under treatment E+M(litter mass:-58.8%,litter C:-57.0%,litter N:-75.1%,respectively),while earthworm biomass significantly decreased under treatment E.Earthworm or millipede addition alone showed no significant effects on the organic carbon(OC)and total nitrogen(TN)content in the POM fraction,but join addition of both significantly increased OC and TN regardless of soil depth.Importantly,all three macrofauna treatments increased the OC and TN content and decreased the^(13)C abundance in the MAOM fraction.More than65%of the total variations in the distribution of OC and TN throughout the two fractions can be explained by a combination of soil physicochemical and microbial properties.Changes in the OC distribution in the 0–5 cm soi layer are likely due to a decrease in soil pH and an increase in arbuscular mycorrhizal fungi(AMF),while those in the 5–10 cm layer are probably caused by increases in soil exchangeable Ca and Mg,in addition to fungi and gram-negative(GN)bacteria.The observed TN distribution changes in the 0–5 cm soil likely resulted from a decrease in soil pH and increases in AMF,GN,and gram-negative(GP)bacteria,while TN distribution changes in the 5–10 cm soil could be explained by increases in exchangeable Mg and GN bacteria.Conclusions:The results indicate that the coexistence of earthworms and millipedes can accelerate the litte decomposition process and store more C in the MAOM fractions.This novel finding helps to unlock the processe by which complex SOM systems serve as C sinks in tropical forests and addresses the importance of soil mac rofauna in maintaining C-neutral atmospheric conditions under global climate change.展开更多
This study assessed the effect of patch scarification and mounding on the physical properties of the root layer and the success of tree planting in various types of forests.This study was conducted on 12 forest sites ...This study assessed the effect of patch scarification and mounding on the physical properties of the root layer and the success of tree planting in various types of forests.This study was conducted on 12 forest sites in taiga forests of the European part of Russia.A total of 54 plots were set up to assess seedling survival;root collar diameter,height,and heigh increment were measured for 240 seedlings to assess growth.In the rooting layer,240 soil samples were taken to determine physical properties.The study showed that soil treatment methods had no effect on bulk density and total porosity in Cladina sites.However,reduced soil moisture was noted,particularly in mounds,resulting in increased aeration.In Myrtillus sites,there were increased bulk density,reduced soil moisture,and total porosity in the mounds.Mounding treatment in Polytrichum sites resulted in reduced soil moisture and increased aeration porosity.In the Myrtillus and Polytrichum sites,patch scarification had no effects on physical properties.In Polytrichum sites,survival rates,heights,and heigh increments of bareroot Norway spruce seedlings in mounds were higher than in patches;however,the same did not apply to diameter.In Cladina and Myrtillus sites,there was no difference in growth for bareroot and containerised seedlings with different soil treatments.Growing conditions and soil types should be considered when applying different soil treatment methods to ensure high survival rates and successful seedling growth.展开更多
With the advancement of agricultural mechanization,soil compaction has become a serious environmental problem.Soil compaction can increase soil bulk density and firmness,reduce porosity and permeability,and deteriorat...With the advancement of agricultural mechanization,soil compaction has become a serious environmental problem.Soil compaction can increase soil bulk density and firmness,reduce porosity and permeability,and deteriorate soil structure,ultimately inhibit sugar beet growth and reduce both root yield and sugar content.However,few farmers recognize the link between soil compaction and these adverse effects.Soil compaction has a cumulative effect,with significant differences observed in the vertical range of compaction accumulation.The most significant soil compaction occurs in the topsoil of 0-10 cm,and the influence depth can reach 70 cm,but it is small in deep soil,and the inflection point is at a soil depth of 10 cm.The degree of soil compaction is related to soil type,water content,tractor shaft load,tyre type,tyre pressure and operation speed,etc.Therefore,in the production process of sugar beet,it is advisable to avoid high-humidity operations,use low pressure tyres,reduce the number of tractor-units passes over the farmland,and implement agricultural and agronomic measures to minimize soil compaction.These practices will help protect the soil environment and ensure sustainable production of sugar beets.展开更多
Biodiversity experiments have shown that soil organic carbon(SOC)is not only a function of plant diversity,but is also closely related to the nitrogen(N)-fixing plants.However,the effect of N-fixing trees on SOC chemi...Biodiversity experiments have shown that soil organic carbon(SOC)is not only a function of plant diversity,but is also closely related to the nitrogen(N)-fixing plants.However,the effect of N-fixing trees on SOC chemical stability is still little known,especially with the compounding effects of tree species diversity.An experimental field manipulation was established in subtropical plantations of southern China to explore the impacts of tree species richness(i.e.,one,two,four and six tree species)and with/without N-fixing trees on SOC chemical stability,as indicated by the ratio of easily oxidized organic carbon to SOC(EOC/SOC).Plant-derived C components in terms of hydrolysable plant lipids and lignin phenols were isolated from soils for evaluating their relative contributions to SOC chemical stability.The results showed that N-fixing tree species rather than tree species richness had a significant effect on EOC/SOC.Hydrolysable plant lipids and lignin phenols were negatively correlated with EOC/SOC,while hydrolysable plant lipids contributed more to EOC/SOC than lignin phenols,especially in the occurrence of N-fixing trees.The presence of N-fixing tree species led to an increase in soil N availability and a decrease in fungal abundance,promoting the selective retention of certain key components of hydrolysable plant lipids,thus enhancing SOC chemical stability.These findings underpin the crucial role of N-fixing trees in shaping SOC chemical stability,and therefore,preferential selection of N-fixing tree species in mixed plantations is an appropriate silvicultural strategy to improve SOC chemical stability in subtropical plantations.展开更多
Background:Soil acidifcationn caused by anthropogenic activities may aft soil biochemical cydling,bidiversity,productivity,and multiple eosystem-related functions in drylands.However,to date,such information is lackin...Background:Soil acidifcationn caused by anthropogenic activities may aft soil biochemical cydling,bidiversity,productivity,and multiple eosystem-related functions in drylands.However,to date,such information is lacking to support this hypothesis.Methods Based on a transect survey of 78 naturally assembled shrub communities,we caloulated acid deposition flux in Northwest China and evaluated its likely ecological ffets by testing three altemnative hypotheses,namely:.nidche complementarity,mass ratio,and vegetation quantity hypotheses Rao's quadratic entopy and community-weighted mean traits were employed to represent the complementary aspect of niche complementarity and mass ratio effects,respectively.Resulbs:We observed that in the past four decades,the concentrations of exchangeable base cations in soil in Northwest China have decreased significantly to the extent of having faced the risk of depletion,whereas changes in the calium carbonate content and pH of soil were not significant.Adid deposition primani ly increased the aboweground biomass and shrub density in shrublands but had no sigmificant effect on shrub richness and ecasystem multifunctionality(EMF),indicating that acid deposition had positive but weak ecological effects on dryland ecosystems.Community wd ghted mean of functional traits(representing the mass ratio hypothesis)correlated negatively with EMF,whereas both Rao's quadratic entropy(representing the niche complementarity hypothesis)and aboveground biomass(representing the vegetation quantity hypothesis)correlated positively but insignifcantly with EMF.These biodiversity-EMF relationships highlight the fragility and instability of drylands relative to forest ecasystems.Concuions:The findings from this study serve as important reference points to understand the ris of soil acidification in arid regions and its impacts on biodiversity-EMF relationships.展开更多
Background As commonly used harvest residue management practices in subtropical plantations,stem only harvesting(SOH)and whole tree harvesting(WTH)are expected to affect soil organic carbon(SOC)content.However,knowled...Background As commonly used harvest residue management practices in subtropical plantations,stem only harvesting(SOH)and whole tree harvesting(WTH)are expected to affect soil organic carbon(SOC)content.However,knowledge on how SOC and its fractions(POC:particulate organic carbon;MAOC:mineral-associated organic carbon)respond to different harvest residue managements is limited.Methods In this study,a randomized block experiment containing SOH and WTH was conducted in a Chinese fir(Cunninghamia lanceolata)plantation.The effect of harvest residue management on SOC and its fractions in topsoil(0–10cm)and subsoil(20–40cm)was determined.Plant inputs(harvest residue retaining mass and fine root biomass)and microbial and mineral properties were also measured.Results The responses of SOC and its fractions to different harvest residue managements varied with soil depth.Specifically,SOH enhanced the content of SOC and POC in topsoil with increases of 15.9%and 29.8%,respectively,compared with WTH.However,SOH had no significant effects on MAOC in topsoil and SOC and its fractions in subsoil.These results indicated that the increase in POC induced by the retention of harvest residue was the primary contributor to SOC accumulation,especially in topsoil.The harvest residue managements affected SOC and its fractions through different pathways in topsoil and subsoil.The plant inputs(the increase in fine root biomass induced by SOH)exerted a principal role in the SOC accumulation in topsoil,whereas mineral and microbial properties played a more important role in regulating SOC dynamics than plants inputs in subsoil.Conclusion The retention of harvest residues can promote SOC accumulation by increasing POC,and is thus suggested as an effective technology to enhance the soil carbon sink for mitigating climate change in plantation management.展开更多
基金This study was financially supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA28020300)the National Natural Science Foundation of China(Grant No.42250410332)+2 种基金the Key Foreign Cooperation Program of the Bureau of International Cooperation of the Chinese Academy of Sciences(Grant No.177GJHZ2022020BS)the‘Double-First Class’Initiative Program for Foreign Talents of Southwest University(Grant No.cstc2021ycjh-bgzxm0002)the‘Prominent Scientist Program’of Chongqing Talents(Grant No.cstc2021ycjh-bgzxm0020)。
文摘Deforestation is one of the most serious environmental problems facing humankind.It continues to escalate rapidly across many regions of the world,thereby deteriorating the forest soil quality.This has prompted a large number of field-based studies aimed at understanding the impacts of deforestation on soil properties.However,the lack of comprehensive meta-analyses that utilized these studies has limited our deeper understanding of how different soil properties,including the soil organic carbon(SOC)pool,respond to deforestation.To address this critical knowledge gap,we conducted a meta-analysis of 144 studies to explore the impacts of deforestation on soil chemical,physical,and biological properties,with special emphasis on the long-term changes in SOC,such as concentrations,stocks,and sequestration.The results revealed that deforestation significantly decreased soil organic matter,electrical conductivity,and base saturation by 52%,50%,and 98%,respectively.While deforestation increased soil total nitrogen content and decreased available phosphorus content by 51%and 99%,respectively,it resulted in slight decreases in some chemical properties,including soil pH(1%)and base cations(1%–13%).Deforestation significantly increased bulk density by 27%and soil erosion by 47%,but significantly decreased soil aggregate stability by 39%and saturated hydraulic conductivity by 63%.Soil microbial biomass C and N concentrations and enzyme activities were significantly decreased as a consequence of deforestation.Soil biological properties were much more affected by deforestation than soil physical and chemical properties.Regarding the SOC,the land use conversion from forest to pasture significantly increased SOC concentrations,stocks,and sequestration rates(11%–13%),whereas the land use conversions from forest to both plantation and cropland significantly decreased SOC concentrations,stocks,and sequestration rates(10%–43%).This observed decline in SOC accumulations decreased with increasing years after deforestation.The SOC dynamics following deforestation were predominantly regulated by microbial biomass concentrations,dehydrogenase activity,soil erosion,saturated hydraulic conductivity,aggregate stability,as well as concentrations of total organic carbon,total nitrogen,total phosphorus and organic matter.The present meta-analytical study provides compelling evidence that deforestation can induce profound changes in soil characteristics,including soil C contents,and has significant implications for soil health sustainability and climate change mitigation.
基金funded by the National Key Research and Development Plan of China(No.2022YFE0127900)the National Natural Science Foundation of China(Nos.32071558,32171559)+2 种基金the Natural Science Foundation Key Project of Inner Mongolia Autonomous Region,China(No.2023ZD23)the Hulunbuir Science and Technology Plan Project(No.SF2022001)the Fundamental Research Funds of CAF(CAFYBB2023ZA002).
文摘Increasing temperatures and severe droughts threaten forest vitality globally.Prediction of forest response to climate change requires knowledge of the spatiotemporal patterns of monthly or seasonal climatic impacts on the growth of tree species,likely driven by local climatic aridity,climate trends,edaphic conditions,and the climatic adaption of tree species.The ability of tree species to cope with changing climate and the effects of environmental variables on growth trends and growth-climate relationships across diverse bioclimatic regions are still poorly understood for many species.This study investigated radial growth trends,interannual growth variability,and growth-climate sensitivity of two dominant tree species,Pinus tabulaeformis(PT)and Pinus sylvestris var.mongolica(PS),across a broad climatic gradient with a variety of soil properties in temperate Northern China.Using a network of 83 tree ring chronologies(54 for PT and 29 for PS)from 1971 to 2010,we documented that both species maintained constant growth trends at wet sites,while both displayed rapid declines at dry sites.We reported the species-specific drivers of spatial heterogeneity in growth trends,interannual growth variability,and growth-climate relationships.Calculated climatic variables and soil properties were identified as the most critical factors affecting the growth trends and growth-climate relationships.However,climatic variables play more essential roles than soil properties in determining the spatial heterogeneity of the growth-climate relationship.Lower clay content and higher soil nutrient regimes can exacerbate the moisture-related susceptibility of tree growth.Our findings highlight that soil properties emerged as important modulating factors to predict the drought vulnerability of forests in addition to climatic variables.Considering the continued climate warmingdrying trend in the future,both pines will face a more severe growth decline and increase in drought vulnerability at drier sites with lower clayed soil or higher nutrient regimes.
基金supported by the Key Research Program of the Institute of Geology and Geophysics,CAS(Nos.IGGCAS-202102 and IGGCAS-201904)the National Natural Science Foundation of China(No.42230111)the CAS Key Technology Talent Program。
文摘After landing in the Utopia Planitia,Tianwen-1 formed the deepest landing crater on Mars,approximately 40 cm deep,exposing precious information about the mechanical properties of Martian soil.We established numerical models for the plume-surface interaction(PSI)and the crater formation based on Computational Fluid Dynamics(CFD)methods and the erosion model modified from Roberts’Theory.Comparative studies of cases were conducted with different nozzle heights and soil mechanical properties.The increase in cohesion and internal friction angle leads to a decrease in erosion rate and maximum crater depth,with the cohesion having a greater impact.The influence of the nozzle height is not clear,as it interacts with the position of the Shock Diamond to jointly control the erosion process.Furthermore,we categorized the evolution of landing craters into the dispersive and the concentrated erosion modes based on the morphological characteristics.Finally,we estimated the upper limits of the Martian soil’s mechanical properties near Tianwen-1 landing site,with the cohesion ranging from 2612 to 2042 Pa and internal friction angle from 25°to 41°.
基金supported by CESAM by FCT/MCTES (UIDP/50017/2020+UIDB/50017/2020+LA/P/0094/2020)and MED (UIDB/05183/2020)to FCT/MEC through national fundsthe co-funding by the FEDER,within the PT2020 Partnership Agreement and Compete 2020,and projects FIRECNUTS (PTDC/AGRCFL/104559/2008)+2 种基金CASCADE (ENV.2011.2.1.4-2/283068),which is funded by the European Unionthe FCT CEEC funding of Frank G.A.Verheijen (CEECIND/02509/2018),Sergio A.Prats (CEECIND/01473/2020),funded by national funds (OE)the SOILCOMBAT project (PTDC/EAM-AMB/0474/2020)through the Portuguese Foundation for Science and Technology (FCT/MCTES).
文摘Soil pedestals have long been used as qualitative indicators of soil splash erosion.In rangelands,plant-capped pedestals,generally grass tussocks,have also been used to quantitatively estimate soil loss since the first half of the twentieth century.In agricultural lands,forests,and bad-lands,stone-capped pedestals have been used as qualitative and semi-quantitative indicators of active,'extreme'erosion.Little work has been reported on using capstone pedestal data for quantifying soil loss.We postulate that three distinct capstone pedestal types may be present in any given location and that a detailed analysis of a pedestal height histogram may be used to recognize their populations.This analysis can subsequently inform if soil loss can be reliably estimated and if so,which of the existing methods using pedestal height data will provide more accurate results.The three proposed capstone pedestal types are:(1)neo-pedestals formed underneath surface stones exposed by(partial)removal of the soil surface cover;(2)endo-pedestals formed underneath stones that were buried in the soil but have been exposed by erosion;and(3)phoenix-pedestals formed underneath stones from collapsed pedestals.In the pedestal height histogram of any given location,a skew to smaller heights may indicate the existence of endo-and/or phoenix-pedestals,which may be revealed as a bi-(or tri)modal distribution when using a smaller bin size.This concept was applied to a case study where soil loss had been monitored for control plots and mulched plots during a 5-year period following wildfire in a eucalypt plantation.We measured pedestal heights and used methods to quantitatively assess soil loss from soil pedestal data in the available literature.Soil pedestal data at the end of the 5-year period under or overestimated soil loss in the control treatment,with results ranging from 60 to 115%of measured soil loss,depending on the method.It is postulated that phoenix-and endo-pedestals may be a driving factor behind the observed discrepancies.We discuss how future research may provide more insight into dominant processes,and how frequency distributions may be used to select the best methods for estimating soil loss from pedestals.
基金the Special Projects for the Central Government to guide the development of local science and technology(ZY20B15)the Key Research&Development Program funding project of Heilongjiang Province(GA21C030)the Research Funds of Provincial Research Institutes of Heilongjiang Province(ZNBZ2022ZR07)。
文摘Methanotrophs,organisms that obtain oxygen by oxidizing methane,are recognized as the only known biological sink for atmospheric CH_4,and forest soil methanotrophs play crucial roles in mitigating global warming.The succession patterns of methanotrophic communities and functions in Wudalianchi volcano forest soils could provide a basis for the study of evolutionary mechanisms between soil microorganisms,the environment,and carbon cycling of temperate forest ecosystems under climate change.In this study,the characteristics and drivers of methanotrophic community structure and function of two volcanic soils at different stages of development are analyzed,including an old volcano and a new volcano,which most recently erupted 300 years and 17-19×10^(5)years ago,respectively,and a non-volcano hills as control,based on space for time substitution and Miseq sequencing and bioinformation technology.The results showed that CH_(4) fluxes were significantly higher in old-stage volcano forest soils than new-stage forest soils and non-volcano forest soils.There were significant differences in the community composition and diversity of soil methanotrophs from different volcano forest soils.Methylococcus was the dominant genus in all soil samples.Additionally,the relative abundance of Methylococcus,along with Clonothrix,Methyloglobulus,Methylomagum,Methylomonas and Methylosarcina,were the important genera responsible for the differences in methanotrophic community structure in different volcano forest soils.The relative abundance of methanotroph belonging toγ-proteobacteria was significantly higher than that belonging toα-proteobacteria(P<0.05).Chao1,Shannon and Simpson indices of soil methanotrophic community were significantly lower in new-stage volcanos and were significantly affected by bulk density,total porosity,p H,nitrate,dissolved organic carbon and dissolved organic nitrogen.There were significant differences in community structure between new-stage and old-stage volcanoes.Bulk density and p H are important soil properties contributing to the divergence of methanotrophs community structure,and changes in soil properties due to soil development time are important factors driving differences in methanotrophs communities in Wudalianchi volcanic soils.
基金Open access funding provided by Universitàdegli Studi di Firenze within the CRUI-CARE Agreement。
文摘There is considerable interest devoted to oldgrowth forests and their capacity to store carbon(C)in biomass and soil.Inventories of C stocks in old-growth forests are carried out worldwide,although there is a lack of information on their actual potential for C sequestration.To further understand this,soil organic carbon(SOC)was measured in one of Italy's best-preserved old-growth forests,the Sasso Fratino Integral Nature Reserve.This reserve is on the World Heritage List along with other ancient beech forests of Europe,and it is virtually untouched due to the steepness of the terrain,even before legal constraints were imposed.Although the sandstone-derived soils are often shallow,they are rich in organic matter.However,no quantification had been carried out.By systematically sampling the topsoil across the forest,we accurately determined the average amount of SOC(62.0±16.9 Mg ha^(–1))and nitrogen(4.0±1.2 Mg ha^(–1))in the top 20 cm.Using the CENTURY model,future dynamics of SOC stocks were predicted to 2050 according to two climate scenarios,A1F1 and B2,the first of high concern and the second more optimistic.The model projected an increase of 0.2 and 0.3 Mg ha^(–1)a^(–1)by 2030 under the A1F1 and B2 scenarios,respectively,suggesting that the topsoil in old-growth forests does not reach equilibrium but continues accumulating SOC.However,from 2030 to 2050,a decline in SOC accumulation is predicted,indicating SOC net loss at high altitudes under the worst-case scenario.This study confirms that soils in oldgrowth forests play a significant role in carbon sequestration.It also suggests that climate change may affect the potential of these forests to store SOC not only in the long term but also in the coming years.
基金supported with the financial support of the National Natural Science Foundation of China(32001311)the Fundamental Research Funds for the Central Universities(2452021017).
文摘Stand age is an important indicator of tree growth and life cycle,and has implications for ecological and biological processes.This study examined changes in soil microbial biomass(SMB)as well as enzyme activities of different aged plantations and revealed their relationship to soil properties.SMB,microbial biomass carbon(MBC),microbial biomass nitrogen(MBN),microbial biomass phos-phorous(MBP)and enzyme activities(β-1,4-glucosidase(β-G),β-1,4-xylosidase(β-X),cellobiohydrolase(CBH),leucine aminopeptidase(LAP),β-1,4-n-acetylglucosamine(NAG)and acid phosphatase(ACP))were measured in Oro-mosia hosiei plantations of different ages.The soil qual-ity index(SQI)model assessed soil quality.SMB contents significantly decreased in young(7-year-old)and mature plantations(45-year-old)compared to middle-aged(20-year-old)plantations.Activity of soilβ-G,β-X,CBH and NAG in the 20-year-old plantations was markedly higher than in the other plantations except forβ-G,CBH and NAG in the 45-year-old plantations.Soil organic carbon(SOC),total potassium(TK),total porosity,dissolved organic carbon,nitrate nitrogen(NO_(3)--N)and non-capillary porosity were key factors affecting SMB,while soil bulk density,pH,SOC,NO_(3)--N,TK and forest litter(FL)were the main factors affecting soil enzyme activities.SQI decreased in the order:middle-aged>mature>young.The efficiency of soil organic matter conversion,the effect of nitrogen min-eralization and fixation by microorganisms,and the better efficiency of phosphorus utilization in mid-age plantations,which improves soil physical properties,better facilitates tree growth,and further improves the buffering of the soil against acidity and alkalinity.FL quality was the only soil biological factor affecting soil enzyme activity.Our findings demonstrate that different aged plantations affect soil micro-bial biomass,enzyme activity,and soil quality.
基金supported by the National Natural Science Foundation of China(Grants 31971463,31930078)the National Key R&D Program of China(Grant 2021YFD2200402)the Chinese Academy of Forestry(Grant CAFYBB2020ZA001).
文摘Different chemical compositions of soil organic carbon(SOC)affect its persistence and whether it signifi-cantly differs between natural forests and plantations remains unclear.By synthesizing 234 observations of SOC chemical compositions,we evaluated global patterns of concentra-tion,individual chemical composition(alkyl C,O-alkyl C,aromatic C,and carbonyl C),and their distribution even-ness.Our results indicate a notably higher SOC,a markedly larger proportion of recalcitrant alkyl C,and lower easily decomposed carbonyl C proportion in natural forests.How-ever,SOC chemical compositions were appreciably more evenly distributed in plantations.Based on the assumed con-ceptual index of SOC chemical composition evenness,we deduced that,compared to natural forests,plantations may have higher possible resistance to SOC decomposition under disturbances.In tropical regions,SOC levels,recalcitrant SOC chemical composition,and their distributed evenness were significantly higher in natural forests,indicating that SOC has higher chemical stability and possible resistance to decomposition.Climate factors had minor effects on alkyl C in forests globally,while they notably affected SOC chemi-cal composition in tropical forests.This could contribute to the differences in chemical compositions and their distrib-uted evenness between plantations and natural stands.
基金the financial support from the National Natural Science Foundation of China(Nos.32001139,32071554)。
文摘Soil organic carbon(SOC)affects the function of terrestrial ecosystem and plays a vital role in global carbon cycle.Yet,large uncertainty still existed regarding the changes in SOC stock and quality with forest succession.Here,the stock and quality of SOC at 1-m soil profile were investigated across a subalpine forest series,including shrub,deciduous broad-leaved forest,broadleaf-conifer mixed forest,middle-age coniferous forest and mature coniferous forest,which located at southeast of Tibetan Plateau.The results showed that SOC stock ranged from 9.8 to29.9 kg·m^(-2),and exhibited a hump-shaped response pattern across the forest successional series.The highest and lowest SOC stock was observed in the mixed forest and shrub forest,respectively.The SOC stock had no significant relationships with soil temperature and litter stock,but was positively correlated with wood debris stock.Meanwhile,the average percentages of polysaccharides,lignins,aromatics and aliphatics based on FTIR spectroscopy were 79.89%,0.94%,18.87%and 0.29%,respectively.Furthermore,the percentage of polysaccharides exhibited an increasing pattern across the forest successional series except for the sudden decreasing in the mixed forest,while the proportions of lignins,aromatics and aliphatics exhibited a decreasing pattern across the forest successional series except for the sudden increasing in the mixed forest.Consequently,the humification indices(HIs)were highest in the mixed forest compared to the other four successional stages,which means that the SOC quality in mixed forest was worse than other successional stages.In addition,the SOC stock,recalcitrant fractions and HIs decreased with increasing soil depth,while the polysaccharides exhibited an increasing pattern.These findings demonstrate that the mixed forest had higher SOC stock and worse SOC quality than other successional stages.The high proportion of SOC stock(66%at depth of 20-100 cm)and better SOC quality(lower HIs)indicate that deep soil have tremendous potential to store SOC and needs more attention under global chan ge.
基金supported by the National Key Research and Development Program of China(2021YFD2200401)the National Natural Science Foundation of China(31901293)。
文摘Afforestation has an important role in biodiversity conservation and ecosystem function improvement.A meta-analysis was carried out in China,which has the largest plantation area globally,to quantify the effects of plantings on soil microbial diversity.The results showed that the overall effect of afforestation on soil microbial diversity was positive across the country.Random forest algorithm suggested that soil carbon was the most important factor regulating microbial diversity and the positive response was only found with new plantings on low-carbon bare lands but not on high-carbon farmlands and grasslands.In addition,afforestation with broadleaved species increased microbial diversity,whereas planting with conifers had no effect on microbial diversity.This study clarified the effects of plantings on soil microbial diversity,which has an important implication for establishing appropriate policies and practices to improve the multiple functionalities(e.g.,biodiversity conservation and climate change mitigation)during plantation establishment.
基金supported by the Major Science and Technology Project of Gansu Province(No.22ZD6FA021-5)the Industrial Support Project of Gansu Province(Nos.2023CYZC-19 and 2021CYZC-22)the Science and Technology Project of Gansu Province(Nos.23YFFA0074,22JR5RA137 and 22JR5RA151).
文摘To obtain more stable spectral data for accurate quantitative analysis of multi-element,especially for the large-area in-situ elements detection of soils, we propose a method for a multielement quantitative analysis of soils using calibration-free laser-induced breakdown spectroscopy(CF-LIBS) based on data filtering. In this study, we analyze a standard soil sample doped with two heavy metal elements, Cu and Cd, with a specific focus on the line of Cu I324.75 nm for filtering the experimental data of multiple sample sets. Pre-and post-data filtering,the relative standard deviation for Cu decreased from 30% to 10%, The limits of detection(LOD)values for Cu and Cd decreased by 5% and 4%, respectively. Through CF-LIBS, a quantitative analysis was conducted to determine the relative content of elements in soils. Using Cu as a reference, the concentration of Cd was accurately calculated. The results show that post-data filtering, the average relative error of the Cd decreases from 11% to 5%, indicating the effectiveness of data filtering in improving the accuracy of quantitative analysis. Moreover, the content of Si, Fe and other elements can be accurately calculated using this method. To further correct the calculation, the results for Cd was used to provide a more precise calculation. This approach is of great importance for the large-area in-situ heavy metals and trace elements detection in soil, as well as for rapid and accurate quantitative analysis.
基金supported by the GuangDong Basic and Applied Basic Research Foundation(2022A1515110439)the National Natural Science Foundation of China(32101393)+1 种基金China Postdoctoral Science Foundation(2023M7339832023M743547)。
文摘Background:Forest soils in tropical and subtropical areas store a significant amount of carbon.Recent framework to assess soil organic matter(SOM)dynamics under evolving global conditions suggest that dividing bulk SOM into particulate and mineral-associated organic matter(POM vs.MAOM)is a promising method for identifying how SOM contributes to reducing global warming.Soil macrofauna,earthworms,and millipedes have been found to play an important role in facilitating SOM processes.However,how these two co-existing macrofaunae impac the litter decomposition process and directly impact the formation of POM and MAOM remains unclear.Methods:Here,we set up a microcosm experiment,which consisted of 20 microcosms with four treatments earthworm and litter addition(E),millipedes and litter addition(M),earthworm,millipedes,and litter addition(E+M),and control(only litter addition)in five replicates.The soil and litter were sterilized prior to beginning the incubation experiment to remove any existing microbes.After incubating the samples for 42 days,the litte properties(mass,C,and N contents),soil physicochemical properties,as well as the C and N contents,and POM and MAOM^(13)C abundance in the 0–5 and 5–10 cm soil layers were measured.Finally,the relative influences o soil physicochemical and microbial properties on the distribution of C and N in the soil fractions were analyzed Results:The litter mass,C,and N associated with all four treatments significantly decreased after incubation especially under treatment E+M(litter mass:-58.8%,litter C:-57.0%,litter N:-75.1%,respectively),while earthworm biomass significantly decreased under treatment E.Earthworm or millipede addition alone showed no significant effects on the organic carbon(OC)and total nitrogen(TN)content in the POM fraction,but join addition of both significantly increased OC and TN regardless of soil depth.Importantly,all three macrofauna treatments increased the OC and TN content and decreased the^(13)C abundance in the MAOM fraction.More than65%of the total variations in the distribution of OC and TN throughout the two fractions can be explained by a combination of soil physicochemical and microbial properties.Changes in the OC distribution in the 0–5 cm soi layer are likely due to a decrease in soil pH and an increase in arbuscular mycorrhizal fungi(AMF),while those in the 5–10 cm layer are probably caused by increases in soil exchangeable Ca and Mg,in addition to fungi and gram-negative(GN)bacteria.The observed TN distribution changes in the 0–5 cm soil likely resulted from a decrease in soil pH and increases in AMF,GN,and gram-negative(GP)bacteria,while TN distribution changes in the 5–10 cm soil could be explained by increases in exchangeable Mg and GN bacteria.Conclusions:The results indicate that the coexistence of earthworms and millipedes can accelerate the litte decomposition process and store more C in the MAOM fractions.This novel finding helps to unlock the processe by which complex SOM systems serve as C sinks in tropical forests and addresses the importance of soil mac rofauna in maintaining C-neutral atmospheric conditions under global climate change.
基金based on studies conducted under a governmental request to“Northern Research Institute of Forestry”for performance of applied research within the remit of the Federal Forestry Agency.Project registration No.122020100319-9。
文摘This study assessed the effect of patch scarification and mounding on the physical properties of the root layer and the success of tree planting in various types of forests.This study was conducted on 12 forest sites in taiga forests of the European part of Russia.A total of 54 plots were set up to assess seedling survival;root collar diameter,height,and heigh increment were measured for 240 seedlings to assess growth.In the rooting layer,240 soil samples were taken to determine physical properties.The study showed that soil treatment methods had no effect on bulk density and total porosity in Cladina sites.However,reduced soil moisture was noted,particularly in mounds,resulting in increased aeration.In Myrtillus sites,there were increased bulk density,reduced soil moisture,and total porosity in the mounds.Mounding treatment in Polytrichum sites resulted in reduced soil moisture and increased aeration porosity.In the Myrtillus and Polytrichum sites,patch scarification had no effects on physical properties.In Polytrichum sites,survival rates,heights,and heigh increments of bareroot Norway spruce seedlings in mounds were higher than in patches;however,the same did not apply to diameter.In Cladina and Myrtillus sites,there was no difference in growth for bareroot and containerised seedlings with different soil treatments.Growing conditions and soil types should be considered when applying different soil treatment methods to ensure high survival rates and successful seedling growth.
基金Supported by China Agriculture Research System(Sugar Crops)of Ministry of Agriculture and Rural Affairs and Ministry of Finance(CARS-170601)Natural Science Foundation of Heilongjiang Province(C201239).
文摘With the advancement of agricultural mechanization,soil compaction has become a serious environmental problem.Soil compaction can increase soil bulk density and firmness,reduce porosity and permeability,and deteriorate soil structure,ultimately inhibit sugar beet growth and reduce both root yield and sugar content.However,few farmers recognize the link between soil compaction and these adverse effects.Soil compaction has a cumulative effect,with significant differences observed in the vertical range of compaction accumulation.The most significant soil compaction occurs in the topsoil of 0-10 cm,and the influence depth can reach 70 cm,but it is small in deep soil,and the inflection point is at a soil depth of 10 cm.The degree of soil compaction is related to soil type,water content,tractor shaft load,tyre type,tyre pressure and operation speed,etc.Therefore,in the production process of sugar beet,it is advisable to avoid high-humidity operations,use low pressure tyres,reduce the number of tractor-units passes over the farmland,and implement agricultural and agronomic measures to minimize soil compaction.These practices will help protect the soil environment and ensure sustainable production of sugar beets.
基金supported by the National Natural Science Foundation of China(31930078,32301559)the Ministry of Science and Technology of China(2021YFD2200405,2021YFD2200402)+1 种基金Fundamental Research Funds of CAF(CAFYBB2021ZW001)the program for scientific research start-up funds of Guangdong Ocean University。
文摘Biodiversity experiments have shown that soil organic carbon(SOC)is not only a function of plant diversity,but is also closely related to the nitrogen(N)-fixing plants.However,the effect of N-fixing trees on SOC chemical stability is still little known,especially with the compounding effects of tree species diversity.An experimental field manipulation was established in subtropical plantations of southern China to explore the impacts of tree species richness(i.e.,one,two,four and six tree species)and with/without N-fixing trees on SOC chemical stability,as indicated by the ratio of easily oxidized organic carbon to SOC(EOC/SOC).Plant-derived C components in terms of hydrolysable plant lipids and lignin phenols were isolated from soils for evaluating their relative contributions to SOC chemical stability.The results showed that N-fixing tree species rather than tree species richness had a significant effect on EOC/SOC.Hydrolysable plant lipids and lignin phenols were negatively correlated with EOC/SOC,while hydrolysable plant lipids contributed more to EOC/SOC than lignin phenols,especially in the occurrence of N-fixing trees.The presence of N-fixing tree species led to an increase in soil N availability and a decrease in fungal abundance,promoting the selective retention of certain key components of hydrolysable plant lipids,thus enhancing SOC chemical stability.These findings underpin the crucial role of N-fixing trees in shaping SOC chemical stability,and therefore,preferential selection of N-fixing tree species in mixed plantations is an appropriate silvicultural strategy to improve SOC chemical stability in subtropical plantations.
基金financially supported by the third xinjiang scientific expedition program (grant no.2022xjkk0901)the Strategic Priority Research Program of Chinese Academy of Sciences (No.XDA2006030102)the National Natural Sciences Foundation of China(No.42171068 and No.42330503)。
文摘Background:Soil acidifcationn caused by anthropogenic activities may aft soil biochemical cydling,bidiversity,productivity,and multiple eosystem-related functions in drylands.However,to date,such information is lacking to support this hypothesis.Methods Based on a transect survey of 78 naturally assembled shrub communities,we caloulated acid deposition flux in Northwest China and evaluated its likely ecological ffets by testing three altemnative hypotheses,namely:.nidche complementarity,mass ratio,and vegetation quantity hypotheses Rao's quadratic entopy and community-weighted mean traits were employed to represent the complementary aspect of niche complementarity and mass ratio effects,respectively.Resulbs:We observed that in the past four decades,the concentrations of exchangeable base cations in soil in Northwest China have decreased significantly to the extent of having faced the risk of depletion,whereas changes in the calium carbonate content and pH of soil were not significant.Adid deposition primani ly increased the aboweground biomass and shrub density in shrublands but had no sigmificant effect on shrub richness and ecasystem multifunctionality(EMF),indicating that acid deposition had positive but weak ecological effects on dryland ecosystems.Community wd ghted mean of functional traits(representing the mass ratio hypothesis)correlated negatively with EMF,whereas both Rao's quadratic entropy(representing the niche complementarity hypothesis)and aboveground biomass(representing the vegetation quantity hypothesis)correlated positively but insignifcantly with EMF.These biodiversity-EMF relationships highlight the fragility and instability of drylands relative to forest ecasystems.Concuions:The findings from this study serve as important reference points to understand the ris of soil acidification in arid regions and its impacts on biodiversity-EMF relationships.
基金supported by the National Natural Science Foundation of China(No.32192434)the National Key Research and Development Program of China(No.2022YFF1303003).
文摘Background As commonly used harvest residue management practices in subtropical plantations,stem only harvesting(SOH)and whole tree harvesting(WTH)are expected to affect soil organic carbon(SOC)content.However,knowledge on how SOC and its fractions(POC:particulate organic carbon;MAOC:mineral-associated organic carbon)respond to different harvest residue managements is limited.Methods In this study,a randomized block experiment containing SOH and WTH was conducted in a Chinese fir(Cunninghamia lanceolata)plantation.The effect of harvest residue management on SOC and its fractions in topsoil(0–10cm)and subsoil(20–40cm)was determined.Plant inputs(harvest residue retaining mass and fine root biomass)and microbial and mineral properties were also measured.Results The responses of SOC and its fractions to different harvest residue managements varied with soil depth.Specifically,SOH enhanced the content of SOC and POC in topsoil with increases of 15.9%and 29.8%,respectively,compared with WTH.However,SOH had no significant effects on MAOC in topsoil and SOC and its fractions in subsoil.These results indicated that the increase in POC induced by the retention of harvest residue was the primary contributor to SOC accumulation,especially in topsoil.The harvest residue managements affected SOC and its fractions through different pathways in topsoil and subsoil.The plant inputs(the increase in fine root biomass induced by SOH)exerted a principal role in the SOC accumulation in topsoil,whereas mineral and microbial properties played a more important role in regulating SOC dynamics than plants inputs in subsoil.Conclusion The retention of harvest residues can promote SOC accumulation by increasing POC,and is thus suggested as an effective technology to enhance the soil carbon sink for mitigating climate change in plantation management.
