Soil organic carbon(SOC)and nitrogen(N)are two of the most important indicators for agricultural productivity.The primary objective of this study was to investigate the changes in SOC and N in the deep soil profile(up...Soil organic carbon(SOC)and nitrogen(N)are two of the most important indicators for agricultural productivity.The primary objective of this study was to investigate the changes in SOC and N in the deep soil profile(up to 100 cm)and their relationships with crop productivity under the influence of long-term(since 1990)fertilization in the wheat-maize cropping system.Treatments included CK(control),NP(inorganic N and phosphorus(P)fertilizers),NPK(inorganic N,P and potassium fertilizers),NPKM(NPK plus manure),and M(manure).Crop yield and the properties of topsoil were measured yearly from 2001 to 2009.C and N contents were measured at five different depths in 2001 and 2009.The results showed that wheat and maize yields decreased between 2001 and 2009 under the inorganic fertilizer(NP and NPK)treatments.The average yield between 2001 and 2009 under the NP,NPK,NPKM,and M treatments(compared with the CK treatment)increased by 38,115,383,and 381%,respectively,for wheat and 348,891,2738,and 1845%,respectively,for maize.Different long-term fertilization treatments significantly changed coarse free particulate(cf POC),fine free particulate(ff POC),intramicroaggregate particulate(i POC),and mineral-associated(m SOC)organic carbon fractions.In the experimental years of 2001 and 2009,soil fractions occurred in the following order for all treatments:m SOC>cf POC>i POC>ff POC.All fractions were higher under the manure application treatments than under the inorganic fertilization treatments.Compared to the inorganic fertilization treatments,manure input enhanced the stocks of SOC and total N in the surface layer(0–20 cm)but decreased SOC and N in the deep soil layer(80–100 cm).This reveals the efficiency of manure in increasing yield productivity and decreasing risk of vertical loss of nutrients,especially N,compared to inorganic fertilization treatments.The findings provide opportunities for understanding deep soil C and N dynamics,which could help mitigate climate change impact on agricultural production and maintain soil health.展开更多
The soil microorganisms at different depths play an important role in soil formation,ecosystem biogeochemistry,recycling of nutrients,and degradation of waste products.The aims of this study were to observe the microb...The soil microorganisms at different depths play an important role in soil formation,ecosystem biogeochemistry,recycling of nutrients,and degradation of waste products.The aims of this study were to observe the microbial diversity in the profile of an agricultural soil in northern China,and to research the correlation between soil microbes and geochemistry.First,the soil geochemistry of the profile was investigated through 25 chemical elements.Secondly,the various physiological groups of microorganisms w...展开更多
Aims Lignin is generally considered as an important indicator of soil organic carbon(SOC)storage and dynamics.to evaluate the effects of plant communities and soil depth on soil lignin is critical to better understand...Aims Lignin is generally considered as an important indicator of soil organic carbon(SOC)storage and dynamics.to evaluate the effects of plant communities and soil depth on soil lignin is critical to better understand forest carbon cycling.Methods We compared lignin content and chemical signature in three soil depths of four major plant communities in a subtropical forest,which located in the north part of Wuling Mountains,China.Lignin was measured using CuO oxidation method.Important Findings Both lignin content and its biochemical signature in plant litter varied among communities.However,these differences were mostly no longer exist in the upper soil layers.Lignin chemistry in soils inherited some of the biochemical signature of lignin in litter,but in a diminished magnitude.these results suggest that different plant communities had similar decomposition process with vary-ing rates,caused diminished differences in lignin content and its biochemical signature.Lignin content decreased with soil depth,but the biochemical signature of lignin was not significantly dif-ferent among soil layers for all communities,which suggests that vertical movement of lignin within the soil profile is very likely a key process causing this similar biochemical signature.these results emphasized the important roles of lignin inputs and soil eluviation in shaping lignin characteristics and distribution in forest soils,which pinpoint the urgent need to consider hydrological processes in studying forest soil carbon cycling.展开更多
Different aggregates vary in their ability to retain or adsorb metals in soil.Five soil profiles were sampled from different soil horizons and grouped,and the concentrations of Al,Mg,Ca,Fe,Mn,Cd,Cu and Pb were determi...Different aggregates vary in their ability to retain or adsorb metals in soil.Five soil profiles were sampled from different soil horizons and grouped,and the concentrations of Al,Mg,Ca,Fe,Mn,Cd,Cu and Pb were determined in six sizes of aggregates(>2,2-1,1-0.6,0.6-0.25,0.25-0.053,<0.053 mm).Significantly high(p<0.05)structural stability indexes(SSI)and ag-gregate stability indexes(ASI)were recorded in the topsoil horizon,which may be attributed to the high soil organic matter(SOM)content in aggregates from topsoil.In addition,ASI and SSI were positively correlated(r=0.569,p<0.05)with each other,which indicated that the stability of soil aggregates could contribute to the structural stability of bulk soil.Moreover,accumulation factors(AF),principal component analysis(PCA)and Pearson's correlation co-efficients were used for metal element assessment.The results indicated that SOM was not a key factor affecting the accumulation of Ca,Mg,Al,Fe,Mn,Pb,Cd and Cu in soil aggre-gates.In general,AF values for metal elements in microaggregates(<0.25 mm)were high,which showed that metals preferred to accumulate in fine soil aggregates.The PCA and Pearson's correlation coefficients indicated that soil parent materials primarily controlled the distribution of Al,Ca,Fe,Mg and Mn,while materials derived from technogenic sources have important impacts on the distribution of Cd,Cu and Pb in soil aggregates along the soil profile.展开更多
Optimization of water and fertilizer coupling management approaches could not only increase apple yield and quality,but also reduce the potential negative impacts of such management activities on the environment.The a...Optimization of water and fertilizer coupling management approaches could not only increase apple yield and quality,but also reduce the potential negative impacts of such management activities on the environment.The aim of the present study was to determine the optimal water-nitrogen(WN)coupling management strategy in an apple orchard in the Weibei Dryland,Shaanxi Province,China,under limited irrigation.A randomized complete block design was adopted to test the effects of three drip irrigation levels(W1,300 m^(3)/hm^(2);W2,600 m^(3)/hm^(2);W3,900 m^(3)/hm^(2))and four N application levels(N0,0 kg/hm^(2);N1,200 kg/hm^(2);N2,400 kg/hm^(2);and N3,600 kg/hm^(2))on N distribution in the 0-100 cm soil profile.Apple yield and economic benefits under different treatments were also evaluated over a three-year period(2012-2014).Compared with the N0W1 treatment,soil N contents were higher and exhibited distinct trends in the soil profile under other treatments.Overall,total N contents exhibited a downward trend from the surface to the subsurface layers(0.11-2.34 g/kg);however,the total N contents of the lower soil layer increased with an increase in irrigation amount.NO_(3)-N contents were the lowest in the 40-60 cm soil layer and then increased with an increase in soil depth.The highest NO_(3)-N contents of different soil layers were observed under the N3W3 treatment,ranging from 124.7 mg/kg(0-20 cm)to 90.9 mg/kg(80-100 cm).NH_(4)^(+)-N contents were low(<10 mg/kg),mainly accumulating in the surface layer and decreasing toward the deeper layers>20 cm.Different water-N coupling treatments also increased apple yield by 7.30%-41.62%when compared with the N0W1 treatment.The highest apple yield(three-year mean:41.01 t/hm^(2))was observed under the N2W2 treatment,with an output value of 237900 RMB yuan/hm^(2) and a net income of 232000 RMB yuan/hm^(2).Considering fruit yield,partial productivity of N fertilizer,and economic and environmental benefits,the N2W2 treatment is the optimal water-N fertilizer coupling drip irrigation scheme for apple production in the study area and other similar dryland areas.展开更多
Soil microorganisms play a key role in the function of soil ecosystem,yet our knowledge about how microbial communities respond to the typically sandy soil environmental properties along the soil profile is still insu...Soil microorganisms play a key role in the function of soil ecosystem,yet our knowledge about how microbial communities respond to the typically sandy soil environmental properties along the soil profile is still insufficient.We investigated the soil microbial community patterns from top(0–20 cm)to clay-layer(>80 cm)of the typical sandy soils in three regions in China with different levels of precipitation,including Lishu County in Jilin Province(LS),Langfang City in Hebei Province(LF)and Zhengzhou City in Henan Province(ZZ).Our findings showed that small-size aggregates(<0.5 mm)rather than large ones(³0.5 mm)dominated the soil profile.The relative abundances of Actinobacteria,Crenarchaeota and Firmicutes were highly related to aggregate proportions of the deep clay-layer soil.The network analysis revealed the distinct community patterns among modules,evidencing niche differentiation along the soil profile.The keystone species OTU_11292 was observed having migrated clearly into the other module of the clay-layer soil.Different roles of the OTU_30(belonging to Gemmatimonadetes)in soil processes might partly explain the different microbial distribution between top-and clay-layer soils.These findings provided new insights into the candidate mechanisms of microbial diversity maintenance and community patterning of sandy soils,which were necessary for better understanding of ecological rules guiding long-term agricultural practice.展开更多
Investigating the dynamics and distribution of soil phosphorus(P) fractions can provide a basis for enhancing P utilization by crops. Four treatments from a 29-year long-term experiment in black soil with maize croppi...Investigating the dynamics and distribution of soil phosphorus(P) fractions can provide a basis for enhancing P utilization by crops. Four treatments from a 29-year long-term experiment in black soil with maize cropping were involved in this study: no fertilizer(CK), inorganic nitrogen and potassium(NK), inorganic nitrogen, phosphorus, and potassium(NPK), and NPK plus manure(NPKM). We analyzed soil P fractions in different soil layers using a modified Hedley sequential method. The long-term NPKM treatment significantly increased total P by 0.6–1.6 times in the different soil layers. The Olsen-P concentration far exceeded the environmental threshold for soil Olsen-P(50.6 mg kg) in the NPKM treatment in the 0–60 cm soil profile. Moreover, the concentrations and proportion of labile and partially labile inorganic P(Pi) fractions(i.e., Na HCO-extracted Pi, Na OH-extracted Pi, and dilute HClextracted Pi) to the sum of all P fractions(Pt) in the 0–60 cm soil profile were higher in the NPKM treatment than in the NPK treatment, indicating that manure could promote the transformation of non-labile into more labile forms of P in soil, possibly by manure reducing P fixation by soil particles. Soil organic matter, Mehlich-3 extractable iron(Fe), and organic-bound aluminum were increased by fertilization, and were the main factors influencing the differences in the P fractions in the 0–20 cm soil layer. Soil mineral components, i.e., free Fe oxide and Ca CO, were the main factors influencing the P fractions in the subsoil. The soil P transformation process varied with soil layer and fertilization. Application of manure fertilizer can increase the labile(Olsen) P concentrations of the various soil layers, and thus should reduce the mineral P fertilizer requirement for crop growth and reduce potential environmental damage.展开更多
Seven soil profiles developed on calcium carbonate–rich slope deposits in the Polish Carpathians were studied in order to:i)determine the micromorphological features of heterogeneous soils formed in a carbonate depos...Seven soil profiles developed on calcium carbonate–rich slope deposits in the Polish Carpathians were studied in order to:i)determine the micromorphological features of heterogeneous soils formed in a carbonate depositional environment,and ii)track primary and secondary calcium carbonate forms and their distribution in such stratified soils.Three cases of soils with different arrangements of calcium carbonate were distinguished,controlled mostly by slope processes.For instance,the increasing content and random distribution of angular and subangular rock fragments found in the overall soil matrix and the irregular coarse:fine size limit suggested different intensities of accumulation and mixing of soil material transported along the slope.Slope processes,together with the calcium carbonate content,mineralogical characteristics and texture influenced the type and arrangement of the bfabric pattern.The calcium carbonate distribution within the soils,besides the obvious inheritance from parent material,was governed by the translocation and mixing of deposits on slopes.The climatic conditions prevailing in the area favour the development of secondary forms of calcium carbonate.However,only three of the seven studied profiles contained pedogenic forms of calcium carbonate,yet they were distributed randomly.The occurrence,distribution and preservation of secondary carbonates depended on the content of primary calcium carbonate and soil features such as texture.The transported material down the slope may indicate a very low content of primary calcium or lack thereof,hence its pedogenic forms could not be created.展开更多
The regulatory functions of soil are getting attention among the scientists and Soil Organic Carbon (SOC) is an important indicator of soil health. The impact of differential use of land on SOC and other edaphic prope...The regulatory functions of soil are getting attention among the scientists and Soil Organic Carbon (SOC) is an important indicator of soil health. The impact of differential use of land on SOC and other edaphic properties were analysed in three important Land use land cover (LULC) system of Tripura, northeast India. Soil cores were divided into four depth profiles (0 - 10, 10 - 30, 30 - 50 and 50 - 100 cm) to observe the changes of edaphic properties into the soil depth gradient. Our results suggest that SOC in the top profile of Managed Plantation (MP) and Jhum Fellow (JF) was 51.68% and 48.55%, less than Natural Forest (NF). From 0 - 10 to 10 - 30 cm soil depth, 43.3%, 8.4% and 39.4% decrease in NF MP and JF found. Total stock of SOC (Mg C·ha<sup>﹣</sup><sup>1</sup>) was found highest in JF (121.87), followed by NF (117.12) and MP (85.34). In top profile, conversion of NF into MP and NF into JF led to 39% and 11% decrease in SOC. The significant variation in SOC stock was found among different LULC under this study (F<sub>2,12</sub> = 16.94, P ≤ 0.001). In 0 - 10 cm soil depth, maximum value of bulk density (gm·cm<sup>﹣</sup><sup>3</sup>) was found in MP (1.39) followed by JF (1.27) and NF (1.23). In top profile, significant variation was found among LULC (p < 0.001). Soil pH and moisture content significantly varied (p < 0.05) in 0 - 10, 10 - 30 and 50 - 100 cm soil depth. In contrast to that significant change in soil temperature was found at 30 - 50 cm (p < 0.001) and 50 - 100 cm (p < 0.001). It was observed that JF had highest overall SOC stock than NF and MP. Conversion of NF into MP and JF results significant loss of SOC at 0 - 10 and 10 - 30 cm depth profile. We also found that NF conversion had significant impact on the change in the soil C pool.展开更多
More than half of the carbon pools in peatlands are stored in the soil layers below 30 cm,yet little is known about the carbon stabilizing factors at these depths.Although iron oxide minerals are considered to be impo...More than half of the carbon pools in peatlands are stored in the soil layers below 30 cm,yet little is known about the carbon stabilizing factors at these depths.Although iron oxide minerals are considered to be important for stabilizing organic carbon(OC),their role in the preservation of OC in peatlands,especially in the deep layers,is poorly understood.Here,we collected 1 m soil profiles from six peatlands in Central and West China to quantitatively study the vertical distribution characteristics of iron-bound OC(Fe-bound OC),and the influencing physicochemical properties of the soil.The results showed that the content of reactive iron(FeR)was enriched in the top layer and decreased gradually with depth.While Fe-bound OC was positively correlated with FeR,its concentration did not decrease with depth in the peat profile.There were no obvious trends in the distributions of FeR and Fe-bound OC with water level fluctuations in the peat profile.In addition,the proportion of Fe-bound OC to soil organic carbon in the deep peat(31 to 100 cm)was equivalent to that in the surface peat(0 to 30 cm),indicating that iron oxide mineral provides comparable protection of OC in both layers.According to upper estimates of global peatland carbon storage(612 Pg),it could be predicted that 23.81±11.75 Pg of OC is protected by association with FeR.These results indicated that iron oxide minerals are the effective"rusty sink"of OC sequestration in peatland,and a key factor for its long-term preservation.The results from this study make a valuable contribution to the carbon dynamics knowledgebase for peatlands,and provide a basis for improved predictive simulations.展开更多
Soil microbial carbon metabolism is critical in wetland soil carbon cycling,and is also a research hotspot at present.However,most studies focus on the surface soil layer in the wetlands and the microorganisms associa...Soil microbial carbon metabolism is critical in wetland soil carbon cycling,and is also a research hotspot at present.However,most studies focus on the surface soil layer in the wetlands and the microorganisms associated with this layer.In this study,0-75 cm soil profiles were collected from five widely separated reed wetlands in the Songnen Plain,which has a large number of middle-high latitude inland saline-sodic wetlands.The Biolog-ECO method was used to determine the carbon metabolic activity and functional diversity of soil microorganisms.The results showed that soil carbon metabolic activity decreased with increasing soil depth.The carbon metabolic activity of soil microorganisms in the 60-75 cm layer was approximately 57.41%-74.60%of that in the 0-15 cm layer.The soil microbial Shannon index and utilization rate of amines decreased with an increase in soil depth,while the Evenness index and utilization rate of polymers tended to increase with soil depth.Dissolved organic carbon(DOC)is the most important factor affecting microbial carbon source utilization preference,because microorganisms mainly obtain the carbon source from DOC.The result of the correlation analysis showed that the soil microbial carbon metabolic activity,Shannon index,and Evenness index significantly correlated with soil total carbon(TC),microbial biomass carbon(MBC),DOC,total nitrogen(TN),ammonium nitrogen(NH_(4)^(+)-N),nitrate nitrogen(NO_(3)_(−)-N)contents,and electrical conductivity(EC).This study emphasized the important role of microbial carbon metabolic function in deep soil.展开更多
This paper briefly assesses the conclusions from the long-term research of soil properties of the banks and shore of Lake Most. This paper mainly deals with the long-term development of the soil parameters of the anth...This paper briefly assesses the conclusions from the long-term research of soil properties of the banks and shore of Lake Most. This paper mainly deals with the long-term development of the soil parameters of the anthropogenic soil profile and, to a lesser extent, the assessment of soil habitats with a typical flora. The experience gained will aid in the planning of further hydrological reclamation.展开更多
The Burdur Lake is located in the southwest of Turkey,and its area has decreased by 40% from 211 km^(2) in 1975 to 126 km^(2) in 2019.In this study,we investigated how the soil has changed in the lacustrine material.T...The Burdur Lake is located in the southwest of Turkey,and its area has decreased by 40% from 211 km^(2) in 1975 to 126 km^(2) in 2019.In this study,we investigated how the soil has changed in the lacustrine material.Three soil profiles were sampled from the former lakebed(chronosequence profiles:P1,2007;P2,1994;and P3,1975),and three soil profiles under different land use types(biosequence profiles:P4,native forest vegetation;P5,agriculture;and P6,lakebed)were sampled.The chronosequence and biosequence soil profiles represented various distances from the Burdur Lake and showed different stages of lacustrine evolution.Soil electrical conductivity(EC;18.1 to 0.4 dS m^(-1)),exchangeable Na^(+)(34.7 to 1.4 cmol kg^(-1))and K^(+)(0.61 to 0.56 cmol kg^(-1)),and water-soluble Cl^(-)(70.3 to 2.1 cmol L^(-1))and SO_(4)^(2-)(275.9 to 25.0 cmol L^(-1))decreased with increasing distance from the Burdur Lake,whereas the A horizon thickness(10 to 48 cm),structure formation(0 to 48 cm),gleization-oxidation depth(0 to 79 cm),and montmorillonite and organic matter(OM;25.9 to 46.0 g kg^(-1))contents increased in the chronosequence soil profiles.The formation of P3 in the chronosequence and P5 in the biosequence soil profiles increased due to longer exposure to pedogenic processes(time,land use,vegetation,etc.).Changes in EC,exchangeable cation(Na^(+) and K^(+))and water-soluble anion(Cl^(-) and SO_(4)^(2-))concentrations of the salt-enriched horizon,OM,gleization-oxidation depth,A horizon thickness,and structure formation of the chronosequence and biosequence soil profiles(especially the topsoil horizon)were highly related to the distance from the Burdur Lake,time,and land use.展开更多
Uncovering the mechanisms underlying the diversity patterns of abundant and rare species is crucial for terrestrial biodiversity maintenance.However,the response of abundant and rare community assembly to ecological s...Uncovering the mechanisms underlying the diversity patterns of abundant and rare species is crucial for terrestrial biodiversity maintenance.However,the response of abundant and rare community assembly to ecological succession has not been explored,particularly considering soil profiles.Here 300 soil samples were collected from reforestation ecosystems from depths of up to 300 cm and horizontal distances of 30–90 cm from a tree.We revealed that soil phosphorus not only affected alpha diversity and community structure,but also mediated the balance of stochastic and deterministic processes for abundant and rare sub-communities,which exhibited contrasting assembly strategies.The abundant sub-community changed from variable selection to stochasticity with the increase of phosphorus,while the rare sub-community shifted from homogeneous selection to stochasticity.Dispersal limitation was the main assembly process in the abundant sub-community,while the rare sub-community was governed primarily by homogeneous selection.Moreover,the relative influence of deterministic processes increased with succession for both sub-communities.At the scale of a single tree,stochastic processes increased with soil depth in rare sub-community,while deterministic processes increased with the radius from a single tree in the abundant subcommunity.Overall,our results highlight the importance of the soil phosphorus-driven assembly process in understanding the re-assembly and maintenance of soil bacterial diversity.展开更多
As one of the most widely distributed bacterial predators in the soil, the role of bacterivorous nematodes on the enhanced bioremediation of polycyclic aromatic hydrocarbon-contaminated soils is crucial, but remains t...As one of the most widely distributed bacterial predators in the soil, the role of bacterivorous nematodes on the enhanced bioremediation of polycyclic aromatic hydrocarbon-contaminated soils is crucial, but remains to be investigated.A microcosm-level study was conducted to examine the effects of bacterial-feeding nematode grazing and tea saponin(TS) addition on bioremediation of a pyrene-contaminated soil enhanced by the polycyclic aromatic hydrocarbon(PAH)-degrading bacterial strain Sphingobium sp.PHE9.After 180 d of incubation, the highest pyrene dissipation(71.3%) was achieved through a combination of Sphingobium sp.PHE9 inoculation with nematode and TS addition.Meanwhile, high counts of culturable PAH-degrading bacteria, soil enzyme activity, and biodiversity indices were observed under the combined treatment, implying that the microbiological function of the contaminated soil was significantly restored.Additionally, the results of Tenax~ extraction with the first-order three-compartment model indicated that rate-limiting factors varied among treatments.The lack of degrading microorganisms was the main rate-limiting factor for the treatments involving TS/nematode addition, and inadequate bioaccessible pyrene was the vital rate-limiting factor in the treatments involving Sphingobium sp.PHE9 inoculation.The proposed combined clean-up strategy proved to be a promising bioremediation technology for aged pyrene-contaminated soils.展开更多
The comprehensive and reliable perception of moisture in a soil profile is essential to irrigation.To establish an efficient method for sensing soil moisture,field trials were conducted to analyze the spatial and temp...The comprehensive and reliable perception of moisture in a soil profile is essential to irrigation.To establish an efficient method for sensing soil moisture,field trials were conducted to analyze the spatial and temporal variations of moisture in a paddy soil profile by using coefficients of variation.The results showed that soil layers at shallow depths undergo more extensive changes in the coefficients of variation.Moisture perception is most sensitive within a depth range of 0-60 cm in the vertical soil profile of a paddy field.By using the clustering algorithm of Euclidean distance,the paddy soil profile was divided into three categories based on soil depth.The first category includes depths ranging from 10-20 cm,the second is from 30-40 cm,and the third is from 50-100 cm.Path analysis indicated that the most sensitive depths for moisture sensing in a paddy soil profile were 20 cm,30 cm,and 50 cm,whereas the most sensitive depths for moisture sensing by time stability analysis were 20 cm,40 cm,and 60 cm.Based on the multiple regression of sensitive depths,the results of quantitative inversion indicated that the time stability analysis results were 0.962 when the(y,y)Coryy of path analysis was 0.980,and the time stability analysis was 0.61 when the root mean square error(RMSE)of path analysis was 0.40.The relative error range between the measured and predicted values of path analysis was less than that of time stability analysis.These findings suggest that it is feasible to effectively sense the moisture of the entire vertical soil profile based on the sensitive depth.The present study has also determined that path analysis is superior to time stability analysis.展开更多
基金financially supported by the National Key Research and Development Program of China(2016YFD0300901 and 2017YFD0800101)the Fundamental Research Funds for Central Non-profit Scientific Institution,China(161032019035,1610132020022 and 1610132020023)。
文摘Soil organic carbon(SOC)and nitrogen(N)are two of the most important indicators for agricultural productivity.The primary objective of this study was to investigate the changes in SOC and N in the deep soil profile(up to 100 cm)and their relationships with crop productivity under the influence of long-term(since 1990)fertilization in the wheat-maize cropping system.Treatments included CK(control),NP(inorganic N and phosphorus(P)fertilizers),NPK(inorganic N,P and potassium fertilizers),NPKM(NPK plus manure),and M(manure).Crop yield and the properties of topsoil were measured yearly from 2001 to 2009.C and N contents were measured at five different depths in 2001 and 2009.The results showed that wheat and maize yields decreased between 2001 and 2009 under the inorganic fertilizer(NP and NPK)treatments.The average yield between 2001 and 2009 under the NP,NPK,NPKM,and M treatments(compared with the CK treatment)increased by 38,115,383,and 381%,respectively,for wheat and 348,891,2738,and 1845%,respectively,for maize.Different long-term fertilization treatments significantly changed coarse free particulate(cf POC),fine free particulate(ff POC),intramicroaggregate particulate(i POC),and mineral-associated(m SOC)organic carbon fractions.In the experimental years of 2001 and 2009,soil fractions occurred in the following order for all treatments:m SOC>cf POC>i POC>ff POC.All fractions were higher under the manure application treatments than under the inorganic fertilization treatments.Compared to the inorganic fertilization treatments,manure input enhanced the stocks of SOC and total N in the surface layer(0–20 cm)but decreased SOC and N in the deep soil layer(80–100 cm).This reveals the efficiency of manure in increasing yield productivity and decreasing risk of vertical loss of nutrients,especially N,compared to inorganic fertilization treatments.The findings provide opportunities for understanding deep soil C and N dynamics,which could help mitigate climate change impact on agricultural production and maintain soil health.
文摘The soil microorganisms at different depths play an important role in soil formation,ecosystem biogeochemistry,recycling of nutrients,and degradation of waste products.The aims of this study were to observe the microbial diversity in the profile of an agricultural soil in northern China,and to research the correlation between soil microbes and geochemistry.First,the soil geochemistry of the profile was investigated through 25 chemical elements.Secondly,the various physiological groups of microorganisms w...
基金This study was supported by the National Natural Science Foundation of China(31270515,31400463)the Chinese National Key Development Program for Basic Research(2014CB954004).
文摘Aims Lignin is generally considered as an important indicator of soil organic carbon(SOC)storage and dynamics.to evaluate the effects of plant communities and soil depth on soil lignin is critical to better understand forest carbon cycling.Methods We compared lignin content and chemical signature in three soil depths of four major plant communities in a subtropical forest,which located in the north part of Wuling Mountains,China.Lignin was measured using CuO oxidation method.Important Findings Both lignin content and its biochemical signature in plant litter varied among communities.However,these differences were mostly no longer exist in the upper soil layers.Lignin chemistry in soils inherited some of the biochemical signature of lignin in litter,but in a diminished magnitude.these results suggest that different plant communities had similar decomposition process with vary-ing rates,caused diminished differences in lignin content and its biochemical signature.Lignin content decreased with soil depth,but the biochemical signature of lignin was not significantly dif-ferent among soil layers for all communities,which suggests that vertical movement of lignin within the soil profile is very likely a key process causing this similar biochemical signature.these results emphasized the important roles of lignin inputs and soil eluviation in shaping lignin characteristics and distribution in forest soils,which pinpoint the urgent need to consider hydrological processes in studying forest soil carbon cycling.
基金This work was supported by the National Key Research and Development Project of China(No.2017YFD0800305).
文摘Different aggregates vary in their ability to retain or adsorb metals in soil.Five soil profiles were sampled from different soil horizons and grouped,and the concentrations of Al,Mg,Ca,Fe,Mn,Cd,Cu and Pb were determined in six sizes of aggregates(>2,2-1,1-0.6,0.6-0.25,0.25-0.053,<0.053 mm).Significantly high(p<0.05)structural stability indexes(SSI)and ag-gregate stability indexes(ASI)were recorded in the topsoil horizon,which may be attributed to the high soil organic matter(SOM)content in aggregates from topsoil.In addition,ASI and SSI were positively correlated(r=0.569,p<0.05)with each other,which indicated that the stability of soil aggregates could contribute to the structural stability of bulk soil.Moreover,accumulation factors(AF),principal component analysis(PCA)and Pearson's correlation co-efficients were used for metal element assessment.The results indicated that SOM was not a key factor affecting the accumulation of Ca,Mg,Al,Fe,Mn,Pb,Cd and Cu in soil aggre-gates.In general,AF values for metal elements in microaggregates(<0.25 mm)were high,which showed that metals preferred to accumulate in fine soil aggregates.The PCA and Pearson's correlation coefficients indicated that soil parent materials primarily controlled the distribution of Al,Ca,Fe,Mg and Mn,while materials derived from technogenic sources have important impacts on the distribution of Cd,Cu and Pb in soil aggregates along the soil profile.
基金financially supported by the Key Research and Development Program of Shaanxi Province,China(Grant No.2019NY-202)the Research Foundation of Education Bureau of Shaanxi Province,China(Grant No.19JS012)the Scientific Research Project of City-University Co-construction of Shaanxi Province for State Key Laboratory of Qinba Bio-Resource and Ecological Environment(SXC-2108).
文摘Optimization of water and fertilizer coupling management approaches could not only increase apple yield and quality,but also reduce the potential negative impacts of such management activities on the environment.The aim of the present study was to determine the optimal water-nitrogen(WN)coupling management strategy in an apple orchard in the Weibei Dryland,Shaanxi Province,China,under limited irrigation.A randomized complete block design was adopted to test the effects of three drip irrigation levels(W1,300 m^(3)/hm^(2);W2,600 m^(3)/hm^(2);W3,900 m^(3)/hm^(2))and four N application levels(N0,0 kg/hm^(2);N1,200 kg/hm^(2);N2,400 kg/hm^(2);and N3,600 kg/hm^(2))on N distribution in the 0-100 cm soil profile.Apple yield and economic benefits under different treatments were also evaluated over a three-year period(2012-2014).Compared with the N0W1 treatment,soil N contents were higher and exhibited distinct trends in the soil profile under other treatments.Overall,total N contents exhibited a downward trend from the surface to the subsurface layers(0.11-2.34 g/kg);however,the total N contents of the lower soil layer increased with an increase in irrigation amount.NO_(3)-N contents were the lowest in the 40-60 cm soil layer and then increased with an increase in soil depth.The highest NO_(3)-N contents of different soil layers were observed under the N3W3 treatment,ranging from 124.7 mg/kg(0-20 cm)to 90.9 mg/kg(80-100 cm).NH_(4)^(+)-N contents were low(<10 mg/kg),mainly accumulating in the surface layer and decreasing toward the deeper layers>20 cm.Different water-N coupling treatments also increased apple yield by 7.30%-41.62%when compared with the N0W1 treatment.The highest apple yield(three-year mean:41.01 t/hm^(2))was observed under the N2W2 treatment,with an output value of 237900 RMB yuan/hm^(2) and a net income of 232000 RMB yuan/hm^(2).Considering fruit yield,partial productivity of N fertilizer,and economic and environmental benefits,the N2W2 treatment is the optimal water-N fertilizer coupling drip irrigation scheme for apple production in the study area and other similar dryland areas.
基金the financial supports of the National Basic Research Program of China(Grant no.2016YFD0200306)the National Natural Science Foundation of China(Grant no.41877412)the Scholarship of the‘National 1000(Young)Talents Program’of China.
文摘Soil microorganisms play a key role in the function of soil ecosystem,yet our knowledge about how microbial communities respond to the typically sandy soil environmental properties along the soil profile is still insufficient.We investigated the soil microbial community patterns from top(0–20 cm)to clay-layer(>80 cm)of the typical sandy soils in three regions in China with different levels of precipitation,including Lishu County in Jilin Province(LS),Langfang City in Hebei Province(LF)and Zhengzhou City in Henan Province(ZZ).Our findings showed that small-size aggregates(<0.5 mm)rather than large ones(³0.5 mm)dominated the soil profile.The relative abundances of Actinobacteria,Crenarchaeota and Firmicutes were highly related to aggregate proportions of the deep clay-layer soil.The network analysis revealed the distinct community patterns among modules,evidencing niche differentiation along the soil profile.The keystone species OTU_11292 was observed having migrated clearly into the other module of the clay-layer soil.Different roles of the OTU_30(belonging to Gemmatimonadetes)in soil processes might partly explain the different microbial distribution between top-and clay-layer soils.These findings provided new insights into the candidate mechanisms of microbial diversity maintenance and community patterning of sandy soils,which were necessary for better understanding of ecological rules guiding long-term agricultural practice.
基金supported by the National Natural Science Foundation of China(41977103 and 41471249)the Reform and Development Fund of Beijing Academy of Agriculture and Forestry Sciences,China(YZS201905)。
文摘Investigating the dynamics and distribution of soil phosphorus(P) fractions can provide a basis for enhancing P utilization by crops. Four treatments from a 29-year long-term experiment in black soil with maize cropping were involved in this study: no fertilizer(CK), inorganic nitrogen and potassium(NK), inorganic nitrogen, phosphorus, and potassium(NPK), and NPK plus manure(NPKM). We analyzed soil P fractions in different soil layers using a modified Hedley sequential method. The long-term NPKM treatment significantly increased total P by 0.6–1.6 times in the different soil layers. The Olsen-P concentration far exceeded the environmental threshold for soil Olsen-P(50.6 mg kg) in the NPKM treatment in the 0–60 cm soil profile. Moreover, the concentrations and proportion of labile and partially labile inorganic P(Pi) fractions(i.e., Na HCO-extracted Pi, Na OH-extracted Pi, and dilute HClextracted Pi) to the sum of all P fractions(Pt) in the 0–60 cm soil profile were higher in the NPKM treatment than in the NPK treatment, indicating that manure could promote the transformation of non-labile into more labile forms of P in soil, possibly by manure reducing P fixation by soil particles. Soil organic matter, Mehlich-3 extractable iron(Fe), and organic-bound aluminum were increased by fertilization, and were the main factors influencing the differences in the P fractions in the 0–20 cm soil layer. Soil mineral components, i.e., free Fe oxide and Ca CO, were the main factors influencing the P fractions in the subsoil. The soil P transformation process varied with soil layer and fertilization. Application of manure fertilizer can increase the labile(Olsen) P concentrations of the various soil layers, and thus should reduce the mineral P fertilizer requirement for crop growth and reduce potential environmental damage.
基金financed by the National Science Centre(Poland)(PRELUDIUM 14 project no.2017/27/N/ST10/00342)the Ministry of Science and Higher Education of the Republic of Poland,No.BM–4112/17 and BM–2120/18。
文摘Seven soil profiles developed on calcium carbonate–rich slope deposits in the Polish Carpathians were studied in order to:i)determine the micromorphological features of heterogeneous soils formed in a carbonate depositional environment,and ii)track primary and secondary calcium carbonate forms and their distribution in such stratified soils.Three cases of soils with different arrangements of calcium carbonate were distinguished,controlled mostly by slope processes.For instance,the increasing content and random distribution of angular and subangular rock fragments found in the overall soil matrix and the irregular coarse:fine size limit suggested different intensities of accumulation and mixing of soil material transported along the slope.Slope processes,together with the calcium carbonate content,mineralogical characteristics and texture influenced the type and arrangement of the bfabric pattern.The calcium carbonate distribution within the soils,besides the obvious inheritance from parent material,was governed by the translocation and mixing of deposits on slopes.The climatic conditions prevailing in the area favour the development of secondary forms of calcium carbonate.However,only three of the seven studied profiles contained pedogenic forms of calcium carbonate,yet they were distributed randomly.The occurrence,distribution and preservation of secondary carbonates depended on the content of primary calcium carbonate and soil features such as texture.The transported material down the slope may indicate a very low content of primary calcium or lack thereof,hence its pedogenic forms could not be created.
文摘The regulatory functions of soil are getting attention among the scientists and Soil Organic Carbon (SOC) is an important indicator of soil health. The impact of differential use of land on SOC and other edaphic properties were analysed in three important Land use land cover (LULC) system of Tripura, northeast India. Soil cores were divided into four depth profiles (0 - 10, 10 - 30, 30 - 50 and 50 - 100 cm) to observe the changes of edaphic properties into the soil depth gradient. Our results suggest that SOC in the top profile of Managed Plantation (MP) and Jhum Fellow (JF) was 51.68% and 48.55%, less than Natural Forest (NF). From 0 - 10 to 10 - 30 cm soil depth, 43.3%, 8.4% and 39.4% decrease in NF MP and JF found. Total stock of SOC (Mg C·ha<sup>﹣</sup><sup>1</sup>) was found highest in JF (121.87), followed by NF (117.12) and MP (85.34). In top profile, conversion of NF into MP and NF into JF led to 39% and 11% decrease in SOC. The significant variation in SOC stock was found among different LULC under this study (F<sub>2,12</sub> = 16.94, P ≤ 0.001). In 0 - 10 cm soil depth, maximum value of bulk density (gm·cm<sup>﹣</sup><sup>3</sup>) was found in MP (1.39) followed by JF (1.27) and NF (1.23). In top profile, significant variation was found among LULC (p < 0.001). Soil pH and moisture content significantly varied (p < 0.05) in 0 - 10, 10 - 30 and 50 - 100 cm soil depth. In contrast to that significant change in soil temperature was found at 30 - 50 cm (p < 0.001) and 50 - 100 cm (p < 0.001). It was observed that JF had highest overall SOC stock than NF and MP. Conversion of NF into MP and JF results significant loss of SOC at 0 - 10 and 10 - 30 cm depth profile. We also found that NF conversion had significant impact on the change in the soil C pool.
基金the Second Tibetan Plateau Scientific Expedition(2019QZKK0304)the Strategic Priority Research Program of Chinese Academy of Sciences(XDA2005010404)the Youth Science and Technology Innovation Team Program of Sichuan Province of China(2021JDTD011).
文摘More than half of the carbon pools in peatlands are stored in the soil layers below 30 cm,yet little is known about the carbon stabilizing factors at these depths.Although iron oxide minerals are considered to be important for stabilizing organic carbon(OC),their role in the preservation of OC in peatlands,especially in the deep layers,is poorly understood.Here,we collected 1 m soil profiles from six peatlands in Central and West China to quantitatively study the vertical distribution characteristics of iron-bound OC(Fe-bound OC),and the influencing physicochemical properties of the soil.The results showed that the content of reactive iron(FeR)was enriched in the top layer and decreased gradually with depth.While Fe-bound OC was positively correlated with FeR,its concentration did not decrease with depth in the peat profile.There were no obvious trends in the distributions of FeR and Fe-bound OC with water level fluctuations in the peat profile.In addition,the proportion of Fe-bound OC to soil organic carbon in the deep peat(31 to 100 cm)was equivalent to that in the surface peat(0 to 30 cm),indicating that iron oxide mineral provides comparable protection of OC in both layers.According to upper estimates of global peatland carbon storage(612 Pg),it could be predicted that 23.81±11.75 Pg of OC is protected by association with FeR.These results indicated that iron oxide minerals are the effective"rusty sink"of OC sequestration in peatland,and a key factor for its long-term preservation.The results from this study make a valuable contribution to the carbon dynamics knowledgebase for peatlands,and provide a basis for improved predictive simulations.
基金the Jilin Scientific and Technological Development Program(20210101091JC)the National Natural Science Foundation of China(41730643,41871090)the Innovation Team Project of Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences(2022CXTD02).
文摘Soil microbial carbon metabolism is critical in wetland soil carbon cycling,and is also a research hotspot at present.However,most studies focus on the surface soil layer in the wetlands and the microorganisms associated with this layer.In this study,0-75 cm soil profiles were collected from five widely separated reed wetlands in the Songnen Plain,which has a large number of middle-high latitude inland saline-sodic wetlands.The Biolog-ECO method was used to determine the carbon metabolic activity and functional diversity of soil microorganisms.The results showed that soil carbon metabolic activity decreased with increasing soil depth.The carbon metabolic activity of soil microorganisms in the 60-75 cm layer was approximately 57.41%-74.60%of that in the 0-15 cm layer.The soil microbial Shannon index and utilization rate of amines decreased with an increase in soil depth,while the Evenness index and utilization rate of polymers tended to increase with soil depth.Dissolved organic carbon(DOC)is the most important factor affecting microbial carbon source utilization preference,because microorganisms mainly obtain the carbon source from DOC.The result of the correlation analysis showed that the soil microbial carbon metabolic activity,Shannon index,and Evenness index significantly correlated with soil total carbon(TC),microbial biomass carbon(MBC),DOC,total nitrogen(TN),ammonium nitrogen(NH_(4)^(+)-N),nitrate nitrogen(NO_(3)_(−)-N)contents,and electrical conductivity(EC).This study emphasized the important role of microbial carbon metabolic function in deep soil.
基金supported by project QJ1520307 entitled“Sustainable Forms of Management in an Anthropogenically Burdened Region”financial support from state budget resources through the KUS program,Ministry of Agriculture of the Czech Republic.
文摘This paper briefly assesses the conclusions from the long-term research of soil properties of the banks and shore of Lake Most. This paper mainly deals with the long-term development of the soil parameters of the anthropogenic soil profile and, to a lesser extent, the assessment of soil habitats with a typical flora. The experience gained will aid in the planning of further hydrological reclamation.
基金supported by the Scientific Research Projects(BAP)(No.2017-2800)of Akdeniz University,Turkeysupported by the Scientific Research Projects(BAP)(No.2019-2757)of Eskisehir Osmangazi University,Turkey for postdoc researchers at the Department of Soil Science,University of Wisconsin-Madison,USA。
文摘The Burdur Lake is located in the southwest of Turkey,and its area has decreased by 40% from 211 km^(2) in 1975 to 126 km^(2) in 2019.In this study,we investigated how the soil has changed in the lacustrine material.Three soil profiles were sampled from the former lakebed(chronosequence profiles:P1,2007;P2,1994;and P3,1975),and three soil profiles under different land use types(biosequence profiles:P4,native forest vegetation;P5,agriculture;and P6,lakebed)were sampled.The chronosequence and biosequence soil profiles represented various distances from the Burdur Lake and showed different stages of lacustrine evolution.Soil electrical conductivity(EC;18.1 to 0.4 dS m^(-1)),exchangeable Na^(+)(34.7 to 1.4 cmol kg^(-1))and K^(+)(0.61 to 0.56 cmol kg^(-1)),and water-soluble Cl^(-)(70.3 to 2.1 cmol L^(-1))and SO_(4)^(2-)(275.9 to 25.0 cmol L^(-1))decreased with increasing distance from the Burdur Lake,whereas the A horizon thickness(10 to 48 cm),structure formation(0 to 48 cm),gleization-oxidation depth(0 to 79 cm),and montmorillonite and organic matter(OM;25.9 to 46.0 g kg^(-1))contents increased in the chronosequence soil profiles.The formation of P3 in the chronosequence and P5 in the biosequence soil profiles increased due to longer exposure to pedogenic processes(time,land use,vegetation,etc.).Changes in EC,exchangeable cation(Na^(+) and K^(+))and water-soluble anion(Cl^(-) and SO_(4)^(2-))concentrations of the salt-enriched horizon,OM,gleization-oxidation depth,A horizon thickness,and structure formation of the chronosequence and biosequence soil profiles(especially the topsoil horizon)were highly related to the distance from the Burdur Lake,time,and land use.
基金the National Science Foundation of China(Grant Nos.:42077222,41807030 and 41830755)。
文摘Uncovering the mechanisms underlying the diversity patterns of abundant and rare species is crucial for terrestrial biodiversity maintenance.However,the response of abundant and rare community assembly to ecological succession has not been explored,particularly considering soil profiles.Here 300 soil samples were collected from reforestation ecosystems from depths of up to 300 cm and horizontal distances of 30–90 cm from a tree.We revealed that soil phosphorus not only affected alpha diversity and community structure,but also mediated the balance of stochastic and deterministic processes for abundant and rare sub-communities,which exhibited contrasting assembly strategies.The abundant sub-community changed from variable selection to stochasticity with the increase of phosphorus,while the rare sub-community shifted from homogeneous selection to stochasticity.Dispersal limitation was the main assembly process in the abundant sub-community,while the rare sub-community was governed primarily by homogeneous selection.Moreover,the relative influence of deterministic processes increased with succession for both sub-communities.At the scale of a single tree,stochastic processes increased with soil depth in rare sub-community,while deterministic processes increased with the radius from a single tree in the abundant subcommunity.Overall,our results highlight the importance of the soil phosphorus-driven assembly process in understanding the re-assembly and maintenance of soil bacterial diversity.
基金financially supported by the National Natural Science Foundation of China(Nos.41371263 and 41771350)the Fundamental Research Funds for the Central Universities of China(Nos.KYTZ201404 and Y0201700160)+3 种基金the Agricultural Science and Technology Innovation Fund of Jiangsu Province,China(No.CX(17)3047)the Agro-scientific Research in the Public Interest of China(No.201503121)the Environmental Protection Research Project in Jiangsu Province,China(No.2017005)the National Key Research and Development Program of China(Nos.2016YFD0200106 and 2016YFD0300908)
文摘As one of the most widely distributed bacterial predators in the soil, the role of bacterivorous nematodes on the enhanced bioremediation of polycyclic aromatic hydrocarbon-contaminated soils is crucial, but remains to be investigated.A microcosm-level study was conducted to examine the effects of bacterial-feeding nematode grazing and tea saponin(TS) addition on bioremediation of a pyrene-contaminated soil enhanced by the polycyclic aromatic hydrocarbon(PAH)-degrading bacterial strain Sphingobium sp.PHE9.After 180 d of incubation, the highest pyrene dissipation(71.3%) was achieved through a combination of Sphingobium sp.PHE9 inoculation with nematode and TS addition.Meanwhile, high counts of culturable PAH-degrading bacteria, soil enzyme activity, and biodiversity indices were observed under the combined treatment, implying that the microbiological function of the contaminated soil was significantly restored.Additionally, the results of Tenax~ extraction with the first-order three-compartment model indicated that rate-limiting factors varied among treatments.The lack of degrading microorganisms was the main rate-limiting factor for the treatments involving TS/nematode addition, and inadequate bioaccessible pyrene was the vital rate-limiting factor in the treatments involving Sphingobium sp.PHE9 inoculation.The proposed combined clean-up strategy proved to be a promising bioremediation technology for aged pyrene-contaminated soils.
基金This work was financially supported by the National Key Research and Development Program of China(2016YFD0300607)the Three New Project of Agricultural Machinery in Jiangsu Province(NJ2017-23)+1 种基金the Independent Innovation of Agricultural Science and Technology in Jiangsu Province(SCX(16)1006)The Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘The comprehensive and reliable perception of moisture in a soil profile is essential to irrigation.To establish an efficient method for sensing soil moisture,field trials were conducted to analyze the spatial and temporal variations of moisture in a paddy soil profile by using coefficients of variation.The results showed that soil layers at shallow depths undergo more extensive changes in the coefficients of variation.Moisture perception is most sensitive within a depth range of 0-60 cm in the vertical soil profile of a paddy field.By using the clustering algorithm of Euclidean distance,the paddy soil profile was divided into three categories based on soil depth.The first category includes depths ranging from 10-20 cm,the second is from 30-40 cm,and the third is from 50-100 cm.Path analysis indicated that the most sensitive depths for moisture sensing in a paddy soil profile were 20 cm,30 cm,and 50 cm,whereas the most sensitive depths for moisture sensing by time stability analysis were 20 cm,40 cm,and 60 cm.Based on the multiple regression of sensitive depths,the results of quantitative inversion indicated that the time stability analysis results were 0.962 when the(y,y)Coryy of path analysis was 0.980,and the time stability analysis was 0.61 when the root mean square error(RMSE)of path analysis was 0.40.The relative error range between the measured and predicted values of path analysis was less than that of time stability analysis.These findings suggest that it is feasible to effectively sense the moisture of the entire vertical soil profile based on the sensitive depth.The present study has also determined that path analysis is superior to time stability analysis.
