Straw return is a promising strategy for managing soil organic carbon(SOC)and improving yield stability.However,the optimal straw return strategy for sustainable crop production in the wheat(Triticum aestivum L.)-cott...Straw return is a promising strategy for managing soil organic carbon(SOC)and improving yield stability.However,the optimal straw return strategy for sustainable crop production in the wheat(Triticum aestivum L.)-cotton(Gossypium hirsutum L.)cropping system remains uncertain.The objective of this study was to quantify the long-term(10 years)impact of carbon(C)input on SOC sequestration,soil aggregation and crop yields in a wheat-cotton cropping system in the Yangtze River Valley,China.Five treatments were arranged with a single-factor randomized design as follows:no straw return(Control),return of wheat straw only(Wt),return of cotton straw only(Ct),return of 50%wheat and 50%cotton straw(Wh-Ch)and return of 100%wheat and 100%cotton straw(Wt-Ct).In comparison to the Control,the SOC content increased by 8.4 to 20.2%under straw return.A significant linear positive correlation between SOC sequestration and C input(1.42-7.19 Mg ha^(−1)yr^(−1))(P<0.05)was detected.The percentages of aggregates of sizes>2 and 1-2 mm at the 0-20 cm soil depth were also significantly elevated under straw return,with the greatest increase of the aggregate stability in the Wt-Ct treatment(28.1%).The average wheat yields increased by 12.4-36.0%and cotton yields increased by 29.4-73.7%,and significantly linear positive correlations were also detected between C input and the yields of wheat and cotton.The average sustainable yield index(SYI)reached a maximum value of 0.69 when the C input was 7.08 Mg ha^(−1)yr^(−1),which was close to the maximum value(SYI of 0.69,C input of 7.19 Mg ha^(−1)yr^(-1))in the Wt-Ct treatment.Overall,the return of both wheat and cotton straw was the best strategy for improving SOC sequestration,soil aggregation,yields and their sustainability in the wheat-cotton rotation system.展开更多
Structural properties of forest soils have important hydro-ecological function and can influence the soil water-physical characters and soil erosion. The experimental soil samples were obtained in surface horizon (0-1...Structural properties of forest soils have important hydro-ecological function and can influence the soil water-physical characters and soil erosion. The experimental soil samples were obtained in surface horizon (0-10 cm) from different subalpine forest types on east slope of Gongga Mountain in the upriver area of Yangtze River China in May 2002. The soil bulk density, porosity, stable infiltration rate, aggregate distribution and particle-size distribution were analyzed by the routine methods in room, and the features and effects on eco-environment of soil aggregation were studied. The results showed that the structure of soil under mixed mature forest is in the best condition and can clearly enhance the eco-environmental function of soil, and the soil structure under the clear-cutting forest is the worst, the others are ranked between them. The study results can offer a basic guidance for the eco-environmental construction in the upper reaches of Yangtze River.展开更多
Soil aggregation plays an important role in agricultural production activities.However,the structure of soil aggregation is destroyed by the natural environment and unreasonable farming management,resulting in the los...Soil aggregation plays an important role in agricultural production activities.However,the structure of soil aggregation is destroyed by the natural environment and unreasonable farming management,resulting in the loss of water,fertilizers and pesticides in soil.At present,hydrogels have been widely reported to promote the formation of soil aggregation.In this paper,amphiphilic calcium alginate(ASA/Ca^(2+))was applied to promote the formation of soil aggregation and enhance pesticide retention.Initially,an ASA was obtained through the one-pot Ugi condensation(a four-component green chemical reaction).Then,ASA/Ca^(2+) hydrogel is prepared by Ca^(2+) cross-linking.The formation of soil aggregation was determined through the Turbiscan Lab Expert stability analyzer,Confocal Laser Scanning Microscope(CLSM),and Transmission Electron Microscope(TEM).And the effect of soil aggregation on acetamiprid environmental behavior was investigated by adsorption kinetics,adsorption isotherms,and leaching.The results shown that the three-dimensional network structure of ASA/Ca^(2+) hydrogel can promote the formation of soil aggregation.Aggregate durability index(ADI)was 0.55 in the presence of ASA/Ca^(2+) hydrogel,indicating that amphiphilic hydrogel can enhance the stability of soil aggregation.The adsorbing capacity of acetamiprid was 1.58 times higher than pure soil,and the release of acetamiprid only about 20%in the presence of ASA/Ca^(2+) hydrogel.These results would be helpful for the formation of soil aggregation and pesticides adsorption on soil aggregation.Thus,ASA/Ca^(2+) hydrogel is likely to improve soil quality,simultaneously it can minimize the mobility of pesticides in the agricultural system.展开更多
Organic amendment is considered as an effective way to increase soil organic carbon （SOC） stock in croplands. To better understand its potential for SOC sequestration, whether SOC saturation could be observed in an ...Organic amendment is considered as an effective way to increase soil organic carbon （SOC） stock in croplands. To better understand its potential for SOC sequestration, whether SOC saturation could be observed in an intensive agricultural ecosystem receiving long-term composted manure were examined. Different SOC pools were isolated by physical fractionation techniques ofa Cambisol soil under a long-term manure experiment with wheat-maize cropping in North China Plain. A field experiment was initiated in 1993, with 6 treatments including control （i.e., without fertilization）, chemical fertilizer only, low rate of traditional composted manure （7.5 t ha-h）, high rate of traditional composted manure （15 t ha-~）, low rate ofbio-composted manure （7.5 t ha-h） and high rate of bio-composted manure （15 t ha-h）. The results showed that consecutive （for up to 20 years） composted manure amendments significantly improved soil macro-aggregation, aggregate associated SOC concentration, and soil structure stability. In detail, SOC concentration in the sand-sized fraction （〉53 ~tm） continued to increase with manure application rate, while the silt （2-53 I.tm） and clay （〈2 ~tm） particles showed no further increase with greater C inputs, exhibiting the C saturation. Further physical separation of small macro-aggregates （250-2 000 tam） into subpools showed that the non-protected coarse particulate organic matter （cPOM, 〉250 pro） was the fraction in which SOC continued to increase with increasing manure application rate. In contrast, the chemical and physical protected C pools （i.e., micro-aggregates and silt-clay occluded in the small macro- aggregates） exhibited no additional C sequestration when the manure application rate was increased. It can be concluded that repeated manure amendments can increase soil macro-aggregation and lead to the increase in relatively stable C pools, showing hierarchical saturation behavior in the intensive cropping system of North China Plain.展开更多
The interaction of soil aggregate dynamics with soil organic carbon is complex with varied spatio-temporal processes in macro-and micro-aggregates. This paper is to determine the aggregation of soil aggregates in purp...The interaction of soil aggregate dynamics with soil organic carbon is complex with varied spatio-temporal processes in macro-and micro-aggregates. This paper is to determine the aggregation of soil aggregates in purple soils （Regosols in FAO Taxonomy or Entisols in USDA Taxonomy） for four types of land use, cropland [corn （Zea mays L.）], orchard （citrus）, forestland （bamboo or cypress）, and barren land （wild grass）, and to explore their relationship with soil organic carbon in the Sichuan basin of southwestern China. Procedures and methods, including manual dry sieving procedure, Yoder＇s wet sieving procedure, pyrophosphates solution method, and Kachisky method, are used to acquire dry, wet, and chemically stable aggregates, and microaggregates. Light and heavy fractions of soil organic carbon were separated using 2.0 g·mL^-1 HgI2-KI mixed solution. The loosely, stably, and tightly combined organic carbon in heavy fraction were separated by extraction with 0.1 M NaOH and 0.1 M NaOH-0.1M Na4P2O7 mixed solution （pH 13）. The results show that the contents of dry and wet macroaggregates 〉0.25 mm in diameter were 974.1 and 900.0 g·kg^-1 highest in red brown purple soils under forestland, while 889.6 and 350.6 g·kg^-1 lowest in dark purple soil and lowest in grey brown purple soils under cropland, respectively. The chemical stability of macroaggregates was lowest in grey brown purple soil with 8.47% under cropland, and highest in red brown purple soil with 69.34% under barren land. The content of microaggregates in dark purple soils was 587g·kg^-1 higher than brown purple soils, while 655g·kg^-1 in red brown purple soils was similar to grey brown purple soils （651g·kg^-1）. Cropland conditions, only 38.4% of organic carbon was of the combined form, and 61.6% of that existed in light fraction. Forestland conditions, 90.7% of organic carbon in red brown purple soil was complexed with minerals as a form of humic substances. The contents and stability of wet aggregates 〉 0.25 mm, contents and stability of chemically stable aggregates 〉0.25 mm, contents of microaggregates 〉 0.01 mm, contents of aggregated primary particle （d〈0.01 mm） and degree of primary particles （d 〈0.01 mm） aggregation were closely related to the concentrations of total soil organic carbon, and loosely and tightly combined organic carbon in heavy fraction. Soil microaggregation could be associated with organic carbon concentration and its combined forms in heavy fraction. There was a direct relationship between microaggregation and macroaggregation of soil primary particles, because the contents of wet aggregates 〉 0.25 mm and its water stability of aggregates were highly correlated with the contents of aggregated primary particle （d 〈 0.01 mm） and the degree of primary particles （d 〈 0.01 mm） aggregation.展开更多
Well-aggregated soil has been shown to improve soil infiltration and reduce runoff and soil erosion, making well-aggregated soil important for productive, sustainable agriculture. One factor that may influence near-su...Well-aggregated soil has been shown to improve soil infiltration and reduce runoff and soil erosion, making well-aggregated soil important for productive, sustainable agriculture. One factor that may influence near-surface soil aggregate stability is fertilizer application. Rapid dissolution of fertilizers, which are mostly salts, can potentially disperse clays and destabilize aggregates. The objective of this study was to evaluate the potential effect of various fertilizer-phosphorus (P) and -nitrogen (N) sources [i.e., triple superphosphate (TSP), monoammonium phosphate (MAP), chemically precipitated struvite (CPST), electrochemically precipitated struvite (ECST), environmentally smart nitrogen (ESN)] and soil depth on water-stable aggregates (WSA) in furrow-irrigated rice on a silt-loam soil (Typic Albaqualf). Total WSA (TWSA) concentration was unaffected (P > 0.05) by fertilizer treatment or soil depth, while WSA concentration was numerically largest (P ∙g<sup>-1</sup>), which did not differ from CPST, ECST, and ESN in the 0 - 5 cm depth or the unamended control in the 0 - 5 and 5 - 10 cm depths, and was at least 1.7 times larger than ESN in the 5 - 10 cm depth (0.03 g∙g<sup>-1</sup>). Results indicated that WSA concentration among non-struvite fertilizer-P sources was generally similar to that from the struvite fertilizer materials. Principal component analysis determined that 32% of the variation of TWSA was mainly explained by changes in soil bulk density, pH, and electrical conductivity. Long-term, continual annual application of fertilizer-P and N could negatively impact soil aggregate stability, soil structure, and potentially erosion.展开更多
Nitrogen(N)loss is a major limiting factor affecting agricultural productivity in saline-alkali soils,with ammonia(NH_(3))volatilization and N leaching being the main sources of N loss.In this study,the dynamics of NH...Nitrogen(N)loss is a major limiting factor affecting agricultural productivity in saline-alkali soils,with ammonia(NH_(3))volatilization and N leaching being the main sources of N loss.In this study,the dynamics of NH_(3)volatilization were measured using the open static chamber method(sponge sampling),alongside the distribution of^(15)N and NO_(3)^(-)-N concentrations in layers,in a 30-cm soil column experiment with vermicompost addition after incorporation of^(15)N-labeled urea in the upper layer(0-10 cm)of a saline-alkali soil.Destructive sampling was conducted on days 20 and 60 of the column experiment to investigate the influencing factors of NH_(3)volatilization and^(15)N/NO_(3)^(-)retention,respectively.The results showed that the addition of vermicompost to saline-alkali soil decreased cumulative NH_(3)volatilization by 45.1%,decreased the^(15)N concentration in the bottom layer(20-30 cm)by 17.1%,and increased the^(15)N concentration in the upper soil by 48.7%.Vermicompost regulated the abundances of amoA,amoC,and nxrA genes,which can decrease NH_(3)volatilization by converting substrate NH_(4)^(+)to NO_(3)^(-).Additionally,Ca^(2+)adsorption is enhanced(increased by 6.2%)by increasing soil cation exchange capacity(increased by 20.6%),thus replacing the adsorption of Na^(+)(decreased by 13.8%)and decreasing the desorption of NH_(4)^(+).Vermicompost enhanced the adsorption of NO_(3)^(-)by increasing Ca^(2+)and Mg^(2+)and decreasing Cl-by 30.4%in the upper soil.This study concluded that vermicompost addition can inhibit N loss by reducing NH_(3)volatilization and improving^(15)N/NO_(3)^(-)retention in saline-alkali soils.展开更多
Both soil organic carbon (SOC) and iron (Fe) oxide content, among other factors, drive the formation and stability of soil aggregates.However, the mechanism of these drivers in greenhouse soil fertilized with organic ...Both soil organic carbon (SOC) and iron (Fe) oxide content, among other factors, drive the formation and stability of soil aggregates.However, the mechanism of these drivers in greenhouse soil fertilized with organic fertilizer is not well understood.In a 3-year field experiment, we aimed to investigate the factors which drive the stability of soil aggregates in greenhouse soil.To explore the impact of organic fertilizer on soil aggregates, we established four treatments:no fertilization (CK);inorganic fertilizer (CF);organic fertilizer (OF);and combined application of inorganic and organic fertilizers(COF).The application of organic fertilizer significantly enhanced the stability of aggregates, that is it enhanced the mean weight diameter, geometric mean diameter and aggregate content (%) of>0.25 mm aggregate fractions.OF and COF treatments increased the concentration of SOC, especially the aliphatic-C, aromatic-C and polysaccharide-C components of SOC, particularly in>0.25 mm aggregates.Organic fertilizer application significantly increased the content of free Fe(Fed), reactive Fe (Feo), and non-crystalline Fe in both bulk soil and aggregates.Furthermore, non-crystalline Fe showed a positive correlation with SOC content in both bulk soil and aggregates.Both non-crystalline Fe and SOC were significantly positively correlated with>2 mm mean weight diameter.Overall, we believe that the increase of SOC, aromatic-C, and non-crystal ine Fe concentrations in soil after the application of organic fertilizer is the reason for improving soil aggregate stability.展开更多
Nitrogen and phosphorus (NP) deposition can change the nutrient input of forest ecosystems. The effects of NP deposition on soil aggregate need to be analyzed to propose effective environmental management strategies. ...Nitrogen and phosphorus (NP) deposition can change the nutrient input of forest ecosystems. The effects of NP deposition on soil aggregate need to be analyzed to propose effective environmental management strategies. In this study, representative Korean pine mixed forests and Korean pine plantations in northeastern China were selected. Soil samples were sieved to obtain four different particle sizes of soil aggregates (> 2, 2–0.25, 0.25–0.053, and < 0.053 mm). Four NP treatments were applied to simulate N and P deposition, and an indoor incubation experiment was conducted over a period of 360 d. Total nitrogen, microbial nitrogen, dissolved organic nitrogen, hydrolyzed nitrogen, NH_(4)^(+)–N, NO_(3)^(−)–N content, and extracellular enzyme activities of NAG, LAP, and AP were determined. Different fractions of N responded differently to NP addition. Lower NP addition had a greater promoting effect on aggregate N compared to higher NP addition. NAG was the main extracellular enzyme affecting N in both forest types. NP addition had a greater effect on the extracellular enzyme activities of the soil aggregates from the Korean pine plantations. These results enhance our understanding of the effects of NP addition on soil nitrogen within temperate forest ecosystems.展开更多
Soil aggregate plays a critical role in the sequestration of soil organic carbon(SOC)on the Qinghai-Tibetan Plateau(QTP).However,the impact of plateau pika(Ochotona curzoniae)on these processes remains uncertain.In th...Soil aggregate plays a critical role in the sequestration of soil organic carbon(SOC)on the Qinghai-Tibetan Plateau(QTP).However,the impact of plateau pika(Ochotona curzoniae)on these processes remains uncertain.In this study,we examined both control and pika disturbed alpine grasslands across various degradation levels,including undegraded(UDM),lightly(LDM),moderately(MDM)and severely(SDM)degraded sites.Through analyzing variations in aggregate size distribution,stability,aggregate associated SOC(ASOC)and bulk SOC(BSOC)concentration,we investigated the influence of plateau pika disturbance on SOC,and compared these effects across varying degradation levels.The results indicate that:(i)pika disturbance decreases soil water content(SWC)by 26.3%and 22.2%in LDM and SDM at the surface soil layer,while increasing SWC by 34.1%and 30.4%in LDM and MDM at the subsurface soil layer.It significantly reduces bulk density(BD)across all soil depths and grassland types,with most significant effect in LDM;(ii)Plateau pika disturbance increases the macroaggregate proportion in both drysieved aggregate(DSA)and water-stable aggregate(WSA),particularly in LDM.It enhances mean weight diameter(MWD)and geometric mean diameter(GMD)for both DSA and WSA,especially in MDM;(iii)Pika disturbance mitigates the negative effect of soil properties on aggregate stability,particularly in LDM and MDM,thereby enhancing the positive effect of aggregate stability on ASOC and improving BSOC content,especially in LDM.These findings provide novel insights into the effects of plateau pika disturbance on SOC dynamics in alpine grasslands.展开更多
Integrated agronomic optimization(IAO)adopts suitable crop varieties,sowing dates,planting density,and advanced nutrient management to redesign the entire production system according to the local environment,and it ca...Integrated agronomic optimization(IAO)adopts suitable crop varieties,sowing dates,planting density,and advanced nutrient management to redesign the entire production system according to the local environment,and it can achieve synergistic improvements in crop yields and resource utilization.However,the intensity and magnitude of the impacts of IAO on soil quality under long-term intensive production and high nitrogen use efficiency(NUE)require further clarification.Based on a 13-year field experiment conducted in Dawenkou,Tai'an,Shadong Province,China,we investigated the effects of four cultivation modes on the grain yield,NUE,and soil aggregate structure,as well as the fraction of organic matter(SOM)and soil quality,reflected by the integrated fertility index(IFI),during the winter wheat maturation periods in 2020–2022.The four cultivation modes were traditional local farming(T1),farmer-based improvement(T2),increased yield regardless of production cost(T3),and integrated soil–crop system management(T4).As the IAO modes,T2 and T4 were characterized by denser planting,reduced nitrogen(N)fertilizer application rates,and delayed sowing compared to T1 and T3,respectively.In this long-term experiment,IAO was found to maintain aggregate stability,increase SOM content(by increasing organic carbon and total nitrogen of the light fraction(LF)and the particulate organic matter fraction(POM)),and improve SOM quality(by increasing the proportions of LF and POM and the ratio of organic carbon to total nitrogen in SOM).Compared to T1,the IFI values of T2,T3,and T4 increased by 10.91,23.38,and 25.55%,and by 17.78,6.41,and 28.94%in the 0–20 and 20–40 cm soil layers,respectively.The grain yield of T4 was 22.52%higher than that of T1,and reached 95.98%of that in T3.Furthermore,the NUE of T4 was 35.61%higher than those of T1 and T3.In conclusion,our results suggest that the IAO mode T4 synergistically increases grain yield and NUE in winter wheat,while maximizing soil quality.展开更多
Crop straw incorporation is widely recommended to maintain crop yields and improve soil organic carbon(SOC)stocks as well as soil quality.However,the long-term effects of different straw incorporation practices on the...Crop straw incorporation is widely recommended to maintain crop yields and improve soil organic carbon(SOC)stocks as well as soil quality.However,the long-term effects of different straw incorporation practices on the SOC stock remain uncertain.In this study,a long-term experiment(2007 to 2018)with four treatments(MW_0:maize–wheat rotation with no straw incorporation,MW_(50):maize–wheat rotation with 50%chopped straw incorporation,MW_(b50):maize–wheat rotation with 50%in situ burned harvested straw,and MF_(50):maize–fallow rotation with 50%harvested maize straw incorporation)was set up to evaluate the response of the SOC stock to different straw incorporation methods.The results showed that the SOC stock significantly increased by 32.4,12.2 and 17.4%under the MW_(50),MW_(b50)and MF_(50)treatments,respectively,after continuous straw incorporation over a decade,while the SOC stock under MW0 was significantly reduced by 22.9%after the 11 year long-term experiment.Compared to MW_0,straw incorporation significantly increased organic carbon input,and improved the soil aggregate structure and the ratio of dissolved organic carbon(DOC)to particulate organic carbon(POC),but it did not significantly stimulate soil heterotrophic respiration,resulting in the increased SOC accumulation rate and SOC stocks of bulk soil.The increased ratio of DOC to microbial biomass carbon(MBC)enhanced the relative abundances of Acidobacteria and Proteobacteria but inhibited Bacteroidetes and Chloroflexi,and the bacterial relative abundances were the main reasons for the non-significant increase or even decrease in soil heterotrophic respiration with straw incorporation.The SOC stock would reach an equilibrium based on the results of Rothamsted carbon(RothC)model simulations,with a long-term equilibrium value of 18.85 Mg ha^(–1)under MW_(50).Overall,the results of the long-term field experiment(2007–2018)and RothC model simulation suggested that maize–wheat rotation with 50%chopped straw incorporation delivered the largest benefits for the SOC stock in calcareous soils of subtropical mountain landscapes over the long term.展开更多
In response to the effectiveness of reforestation in controlling soil erosion,there has been a dramatic increase in forest coverage in the hilly red soil region of southern China.Aggregate stability and soil shear str...In response to the effectiveness of reforestation in controlling soil erosion,there has been a dramatic increase in forest coverage in the hilly red soil region of southern China.Aggregate stability and soil shear strength are indicators that reflect soil resistance to erosion and its ability to prevent shallow landslides,respectively.However,limited research has focused on the response of soil aggregate stability and shear strength to reforestation.We selected three types of reforestations(Phyllostachys edulis forest,Cunninghamia lanceolata(Lamb.)Hook.forest,Citrus sinensis(L.)Osbeck.orchard),a natural forest(mixed coniferous and broadleaf forests),and a fallow land as study plots,and measured root traits,and soil physicochemical traits,i.e.,pH,soil organic matter(SOC),Soil water content(SWC),soil bulk density(BD),soil cohesion(c),soil internal friction angle(φ)and analyzed their multiple interactions.The soil aggregate stability traits,refer to the mean weight diameter(MWD)and geometric mean diameter(GMD),exhibited a significant increase in reforested plots,approximately 200%compared to fallow land and 50%compared to natural forests.For soil shear strength the values were approximately 20%higher than in fallow land and approximately 10%lower than in natural forests.Soil aggregate stability and soil shear strength did not exhibit a significant positive correlation across all plots,and the underlying drivers of these traits were variable.For instance,in natural forest and timber stands,soil aggregate stability was mainly influenced by soil organic carbon,while soil shear strength was primarily affected by root length density.In economic forest,aggregate stability and shear strength are mainly affected by organic carbon.Overall,we found that vegetation restoration enhances soil erosion resistance,however,the primary drivers for the improvement of aggregate stability(soil organic carbon)and shear strength(root length density)are different.Therefore,in future benefit assessments of vegetation restoration projects aimed at soil erosion control,different indicators should be considered based on specific conditions.展开更多
Soil aggregation is one of the crucial processes that facilitate carbon sequestration and maintain soil fertility.So far,the effect of biochar amendment on soil aggregation remains inconclusive.Here,we tested the hypo...Soil aggregation is one of the crucial processes that facilitate carbon sequestration and maintain soil fertility.So far,the effect of biochar amendment on soil aggregation remains inconclusive.Here,we tested the hypothesis that the response of soil aggregation to biochar addition varied with incubation duration and biochar chemistry.A one year microcosm experiment of soil with biochar was conducted that included biochar produced at three different temperatures(300,450,and 600°C),and three biochar application rates,i.e.,0,1,and 3 wt%.It was observed that after one and three months,biochar mainly(>90%)distributed in the micro-aggregates,and slightly reduced aggregate stability and increased proportion of micro-aggregates,which was demonstrated to result from the mechanical mixture of amended biochar with soil.Contrastingly,when the duration was prolonged to six months and one year,a significant increase in macro-aggregates(6.6-38.5%)and aggregate stability(7.3-29.4%)was detected,with the increasing extent being apparently higher for low-temperature biochar.This was related to the comparatively strong interaction of biochar particles with soil minerals or microbes after long-time incubation.The strong interaction was directly supported by the significant increase in H/C,O/C ratios of isolated biochar from treated soils,the detection of typical soil mineral elements on the surface of isolated biochar,and the increase in microbial biomass carbon of treated soils.The findings of this study highlighted the role of biochar type and amendment duration in mediating the effect of biochar application on soil aggregation.展开更多
Soil health is an important component of“One Health”.Soils provide habitat to diverse and abundant organisms.Understanding microbial diversity and functions is essential for building healthy soils towards sustainabl...Soil health is an important component of“One Health”.Soils provide habitat to diverse and abundant organisms.Understanding microbial diversity and functions is essential for building healthy soils towards sustainable agriculture.Arbuscular mycorrhizal fungi(AMF)form potentially symbiotic associations with approximately 80%of land plant species that are well recognized for carbon flux and nutrient cycling.In addition to disentangling the signaling pathways and regulatory mechanisms between the two partners,recent advances in hyphosphere research highlight some emerging roles of AMF and associated microbes in the delivery of soil functions.This paper reviews the contribution of AMF to soil health in agroecosystems,with a major focus on recent progress in the contribution of hyphosphere microbiome to nutrient cycling,carbon sequestration,and soil aggregation.The hyphosphere microbiome and fungal stimulants open avenues for developing new fertilizer formulas to promote AMF benefits.In practice,developing AMF-friendly management strategies will have long-term positive effects on sustainable agriculture aiming at simultaneously providing food security,increasing resource use efficiency,and maintaining environment integrity.展开更多
Soil aggregate fractions can regulate microbial community composition and structure after vegetation restoration.However,there has been less focus on the effects of soil aggregate fractions on the distributions of mic...Soil aggregate fractions can regulate microbial community composition and structure after vegetation restoration.However,there has been less focus on the effects of soil aggregate fractions on the distributions of microbial communities.Here,we used phospholipid fatty acid(PLFA)analysis to explore the effects of different years of vegetation restoration(a 35-year-old Thymus mongolicus community(Re-35yrs)and a 2-year-old nongrazing grassland(Ug-2yrs))on microbial communities within different soil aggregate sizes(<0.25 mm,0.25–1 mm,1–2 mm,2–3 mm,3–5 mm and>5 mm).The results indicated that the amount of total PLFA in Re-35yrs was 10 times greater than that in Ug-2yrs.The soil aggregate stability increased with increasing duration of vegetation restoration.In Re-35yrs,the total PLFA shown an increase as the soil aggregate size increased,and the highest values were observed in 3–5 mm.Ug-2yrs differed from Re-35yrs,the soil microbial diversity was higher in medium particle sizes(1–2 mm and 2–3 mm)and lower in microaggregates(<0.25 mm and 0.25–1 mm)and macroaggregates(3–5 mm and>5 mm).Soil microbial diversity was highest in large particle size aggregates,which resulted in low environmental stress and strong stability.The same tendency was observed in the high values of cyc/prec,S/M and soil organic matter,which indicated a lower turnover speed(F/B)of fungal energy utilization and a higher fixation rate.After years of natural restoration,the soil microbial community generally transformed from nutrient-rich to heterotrophdominant,especially in microaggregates(reflected in the G^(+)/G^(–)ratio).展开更多
Tillage practices during the fallow period benefit water storage and yield in dryland wheat crops.However,there is currently no clarity on the responses of soil organic carbon(SOC),total nitrogen(TN),and available nut...Tillage practices during the fallow period benefit water storage and yield in dryland wheat crops.However,there is currently no clarity on the responses of soil organic carbon(SOC),total nitrogen(TN),and available nutrients to tillage practices within the growing season.This study evaluated the effects of three tillage practices(NT,no tillage;SS,subsoil tillage;DT,deep tillage)over five years on soil physicochemical properties.Soil samples at harvest stage from the fifth year were analyzed to determine the soil aggregate and aggregate-associated C and N fractions.The results indicated that SS and DT improved grain yield,straw biomass and straw carbon return of wheat compared with NT.In contrast to DT and NT,SS favored SOC and TN concentrations and stocks by increasing the soil organic carbon sequestration rate(SOCSR)and soil nitrogen sequestration rate(TNSR)in the 0-40 cm layer.Higher SOC levels under SS and NT were associated with greater aggregate-associated C fractions,while TN was positively associated with soluble organic nitrogen(SON).Compared with DT,the NT and SS treatments improved soil available nutrients in the 0-20 cm layer.These findings suggest that SS is an excellent practice for increasing soil carbon,nitrogen and nutrient availability in dryland wheat fields in North China.展开更多
The conversion of natural forests in subtropical regions to plantations or secondary forests has resulted in alterations in soil variables,microbial communities,and microbially mediated processes,including nitrous oxi...The conversion of natural forests in subtropical regions to plantations or secondary forests has resulted in alterations in soil variables,microbial communities,and microbially mediated processes,including nitrous oxide(N_(2)O)emissions.However,how forest conversion influences soil N_(2)O reduction and the abundance and community structure of N_(2)O-reducing microorganisms remains unclear.Here,we investigated the impact of converting natural forests to a secondary forest and Cunninghamia lanceolata and Pinus massoniana plantations on the abundance and community structure of N_(2)O-reducing microorganisms in both bulk soils and soil aggregates.Compared with the secondary forest,plantations had higher soil pH and available phosphorus and moisture contents,lower soil NH_(4)^(+)content,but similar aggregate sizes.Compared with the secondary forest,the conversion of natural forest to plantations resulted in significantly higher soil N_(2)O reduction rate and increased abundances of nosZⅠand nosZⅡgenes in bulk soils and soil aggregates.The abundance of nosZⅠwas higher than that of nosZⅡin all tested soils and had a stronger association with N_(2)O reduction rate,suggesting the greater role of nosZⅠ-carrying microorganisms in N_(2)O consumption.Forest conversion had a greater impact on the community composition of nosZ I than nosZⅡ,mainly by increasing the relative abundances of alpha-and beta-Proteobacteria,while decreasing gamma-Proteobacteria.However,nosZⅡ-carrying microorganisms were exclusively dominated by Gemmatimonadetes and less affected by forest conversion.Taken together,our findings significantly contribute to our understanding of the eco-physiological characteristics of N_(2)O-reducing microorganisms and highlight the importance of nosZⅠ-carrying microorganisms in N_(2)O consumption in subtropical forest soils.展开更多
Soil aggregate is the basic structural unit of soil,which is the foundation for supporting ecosystem functions,while its composition and stability is significantly affected by the external environment.This study was c...Soil aggregate is the basic structural unit of soil,which is the foundation for supporting ecosystem functions,while its composition and stability is significantly affected by the external environment.This study was conducted to explore the effect of external environment(wetting-drying cycles and acidic conditions)on the soil aggregate distribution and stability and identify the key soil physicochemical factors that affect the soil aggregate stability.The yellow‒brown soil from the Three Gorges Reservoir area(TGRA)was used,and 8 wetting-drying conditions(0,1,2,3,4,5,10 and 15 cycles)were simulated under 4 acidic conditions(pH=3,4,5 and 7).The particle size distribution and soil aggregate stability were determined by wet sieving method,the contribution of environmental factors(acid condition,wetting-drying cycle and their combined action)to the soil aggregate stability was clarified and the key soil physicochemical factors that affect the soil aggregate stability under wetting-drying cycles and acidic conditions were determined by using the Pearson’s correlation analysis,Partial least squares path modeling(PLS‒PM)and multiple linear regression analysis.The results indicate that wetting-drying cycles and acidic conditions have significant effects on the stability of soil aggregates,the soil aggregate stability gradually decreases with increasing number of wetting-drying cycles and it obviously decreases with the increase of acidity.Moreover,the combination of wetting-drying cycles and acidic conditions aggravate the reduction in the soil aggregate stability.The wetting-drying cycles,acidic conditions and their combined effect imposes significant impact on the soil aggregate stability,and the wetting-drying cycles exert the greatest influence.The soil aggregate stability is significantly correlated with the pH,Ca^(2+),Mg^(2+),maximum disintegration index(MDI)and soil bulk density(SBD).The PLS‒PM and multiple linear regression analysis further reveal that the soil aggregate stability is primarily influenced by SBD,Ca^(2+),and MDI.These results offer a scientific basis for understanding the soil aggregate breakdown mechanism and are helpful for clarifying the coupled effect of wetting-drying cycles and acid rain on terrestrial ecosystems in the TGRA.展开更多
We studied changes in the concentrations of aggregate-cementing agents after different reclamation times and with different fertilization regimes,as well as the formation mechanism of aggregates in reclaimed soil,to p...We studied changes in the concentrations of aggregate-cementing agents after different reclamation times and with different fertilization regimes,as well as the formation mechanism of aggregates in reclaimed soil,to provide a theoretical basis for rapid reclamation of soil fertility in the subsidence area of coal mines in Shanxi Province,China.In this study,soil samples of 0–20 cm depth were collected from four fertilization treatments of a longterm experiment started in 2008:no fertilizer (CK),inorganic fertilizer (NPK),chicken manure compost (M),and50%inorganic fertilizer plus 50%chicken manure compost (MNPK).The concentrations of cementing agents and changes in soil aggregate size distribution and stability were analysed.The results showed that the formation of>2 mm aggregates,the aggregate mean weight diameter (MWD),and the proportion of>0.25 mm water-stable aggregates (WR_(0.25)) increased significantly after 6 and 11 years of reclamation.The concentration of organic cementing agents tended to increase with reclamation time,whereas free iron oxide (Fed) and free aluminium oxide(Ald) concentrations initially increased but then decreased.In general,the MNPK treatment signi?cantly increased the concentrations of organic cementing agents and CaCO_(3),and CaCO_(3) increased by 60.4%at 11 years after reclamation.Additionally,CaCO_(3) had the greatest effect on the stability of aggregates,promoting the formation of>0.25 mm aggregates and accounting for 54.4%of the variance in the proportion and stability of the aggregates.It was concluded that long-term reclamation is bene?cial for improving soil structure.The MNPK treatment was the most effective measure for increasing maize grain yield and concentration of organic cementing agents and CaCO_(3).展开更多
基金supported by the National Natural Science Foundation of China(32071968)the Jiangsu Agricultural Science and Technology Innovation Fund,China(CX(22)2015))the Jiangsu Collaborative Innovation Center for Modern Crop Production,China。
文摘Straw return is a promising strategy for managing soil organic carbon(SOC)and improving yield stability.However,the optimal straw return strategy for sustainable crop production in the wheat(Triticum aestivum L.)-cotton(Gossypium hirsutum L.)cropping system remains uncertain.The objective of this study was to quantify the long-term(10 years)impact of carbon(C)input on SOC sequestration,soil aggregation and crop yields in a wheat-cotton cropping system in the Yangtze River Valley,China.Five treatments were arranged with a single-factor randomized design as follows:no straw return(Control),return of wheat straw only(Wt),return of cotton straw only(Ct),return of 50%wheat and 50%cotton straw(Wh-Ch)and return of 100%wheat and 100%cotton straw(Wt-Ct).In comparison to the Control,the SOC content increased by 8.4 to 20.2%under straw return.A significant linear positive correlation between SOC sequestration and C input(1.42-7.19 Mg ha^(−1)yr^(−1))(P<0.05)was detected.The percentages of aggregates of sizes>2 and 1-2 mm at the 0-20 cm soil depth were also significantly elevated under straw return,with the greatest increase of the aggregate stability in the Wt-Ct treatment(28.1%).The average wheat yields increased by 12.4-36.0%and cotton yields increased by 29.4-73.7%,and significantly linear positive correlations were also detected between C input and the yields of wheat and cotton.The average sustainable yield index(SYI)reached a maximum value of 0.69 when the C input was 7.08 Mg ha^(−1)yr^(−1),which was close to the maximum value(SYI of 0.69,C input of 7.19 Mg ha^(−1)yr^(-1))in the Wt-Ct treatment.Overall,the return of both wheat and cotton straw was the best strategy for improving SOC sequestration,soil aggregation,yields and their sustainability in the wheat-cotton rotation system.
基金This study was supported by the Knowledge innovation project of Chinese Academy of Sciences (KZCX2-Sw-319)
文摘Structural properties of forest soils have important hydro-ecological function and can influence the soil water-physical characters and soil erosion. The experimental soil samples were obtained in surface horizon (0-10 cm) from different subalpine forest types on east slope of Gongga Mountain in the upriver area of Yangtze River China in May 2002. The soil bulk density, porosity, stable infiltration rate, aggregate distribution and particle-size distribution were analyzed by the routine methods in room, and the features and effects on eco-environment of soil aggregation were studied. The results showed that the structure of soil under mixed mature forest is in the best condition and can clearly enhance the eco-environmental function of soil, and the soil structure under the clear-cutting forest is the worst, the others are ranked between them. The study results can offer a basic guidance for the eco-environmental construction in the upper reaches of Yangtze River.
基金suppoted by the Key Projects in the Hainan provincial Science&Technology Program(No.ZDYF2020191)the National Natural Science Foundation of China(Nos.22068011,22007025)+1 种基金the Natural Science Foundation of Hainan Province(Nos.220MS006,220QN182)the Start-up Grants from Hainan University(Nos.KYQD(ZR)20041,KYQD(ZR)20040).
文摘Soil aggregation plays an important role in agricultural production activities.However,the structure of soil aggregation is destroyed by the natural environment and unreasonable farming management,resulting in the loss of water,fertilizers and pesticides in soil.At present,hydrogels have been widely reported to promote the formation of soil aggregation.In this paper,amphiphilic calcium alginate(ASA/Ca^(2+))was applied to promote the formation of soil aggregation and enhance pesticide retention.Initially,an ASA was obtained through the one-pot Ugi condensation(a four-component green chemical reaction).Then,ASA/Ca^(2+) hydrogel is prepared by Ca^(2+) cross-linking.The formation of soil aggregation was determined through the Turbiscan Lab Expert stability analyzer,Confocal Laser Scanning Microscope(CLSM),and Transmission Electron Microscope(TEM).And the effect of soil aggregation on acetamiprid environmental behavior was investigated by adsorption kinetics,adsorption isotherms,and leaching.The results shown that the three-dimensional network structure of ASA/Ca^(2+) hydrogel can promote the formation of soil aggregation.Aggregate durability index(ADI)was 0.55 in the presence of ASA/Ca^(2+) hydrogel,indicating that amphiphilic hydrogel can enhance the stability of soil aggregation.The adsorbing capacity of acetamiprid was 1.58 times higher than pure soil,and the release of acetamiprid only about 20%in the presence of ASA/Ca^(2+) hydrogel.These results would be helpful for the formation of soil aggregation and pesticides adsorption on soil aggregation.Thus,ASA/Ca^(2+) hydrogel is likely to improve soil quality,simultaneously it can minimize the mobility of pesticides in the agricultural system.
基金funded by the National Natural Science Foundation of China(31261140367,31170489 and 30870414)the China Postdoctoral Science Foundation(201104164 and 20100470408)the S&T Innovation Program of Chinese Academy of Agricultural Sciences
文摘Organic amendment is considered as an effective way to increase soil organic carbon （SOC） stock in croplands. To better understand its potential for SOC sequestration, whether SOC saturation could be observed in an intensive agricultural ecosystem receiving long-term composted manure were examined. Different SOC pools were isolated by physical fractionation techniques ofa Cambisol soil under a long-term manure experiment with wheat-maize cropping in North China Plain. A field experiment was initiated in 1993, with 6 treatments including control （i.e., without fertilization）, chemical fertilizer only, low rate of traditional composted manure （7.5 t ha-h）, high rate of traditional composted manure （15 t ha-~）, low rate ofbio-composted manure （7.5 t ha-h） and high rate of bio-composted manure （15 t ha-h）. The results showed that consecutive （for up to 20 years） composted manure amendments significantly improved soil macro-aggregation, aggregate associated SOC concentration, and soil structure stability. In detail, SOC concentration in the sand-sized fraction （〉53 ~tm） continued to increase with manure application rate, while the silt （2-53 I.tm） and clay （〈2 ~tm） particles showed no further increase with greater C inputs, exhibiting the C saturation. Further physical separation of small macro-aggregates （250-2 000 tam） into subpools showed that the non-protected coarse particulate organic matter （cPOM, 〉250 pro） was the fraction in which SOC continued to increase with increasing manure application rate. In contrast, the chemical and physical protected C pools （i.e., micro-aggregates and silt-clay occluded in the small macro- aggregates） exhibited no additional C sequestration when the manure application rate was increased. It can be concluded that repeated manure amendments can increase soil macro-aggregation and lead to the increase in relatively stable C pools, showing hierarchical saturation behavior in the intensive cropping system of North China Plain.
基金the National Natural Science Foundation of China(40231016)the National Key Technologies R&D Program of China(2006BAD05B01-02)
文摘The interaction of soil aggregate dynamics with soil organic carbon is complex with varied spatio-temporal processes in macro-and micro-aggregates. This paper is to determine the aggregation of soil aggregates in purple soils （Regosols in FAO Taxonomy or Entisols in USDA Taxonomy） for four types of land use, cropland [corn （Zea mays L.）], orchard （citrus）, forestland （bamboo or cypress）, and barren land （wild grass）, and to explore their relationship with soil organic carbon in the Sichuan basin of southwestern China. Procedures and methods, including manual dry sieving procedure, Yoder＇s wet sieving procedure, pyrophosphates solution method, and Kachisky method, are used to acquire dry, wet, and chemically stable aggregates, and microaggregates. Light and heavy fractions of soil organic carbon were separated using 2.0 g·mL^-1 HgI2-KI mixed solution. The loosely, stably, and tightly combined organic carbon in heavy fraction were separated by extraction with 0.1 M NaOH and 0.1 M NaOH-0.1M Na4P2O7 mixed solution （pH 13）. The results show that the contents of dry and wet macroaggregates 〉0.25 mm in diameter were 974.1 and 900.0 g·kg^-1 highest in red brown purple soils under forestland, while 889.6 and 350.6 g·kg^-1 lowest in dark purple soil and lowest in grey brown purple soils under cropland, respectively. The chemical stability of macroaggregates was lowest in grey brown purple soil with 8.47% under cropland, and highest in red brown purple soil with 69.34% under barren land. The content of microaggregates in dark purple soils was 587g·kg^-1 higher than brown purple soils, while 655g·kg^-1 in red brown purple soils was similar to grey brown purple soils （651g·kg^-1）. Cropland conditions, only 38.4% of organic carbon was of the combined form, and 61.6% of that existed in light fraction. Forestland conditions, 90.7% of organic carbon in red brown purple soil was complexed with minerals as a form of humic substances. The contents and stability of wet aggregates 〉 0.25 mm, contents and stability of chemically stable aggregates 〉0.25 mm, contents of microaggregates 〉 0.01 mm, contents of aggregated primary particle （d〈0.01 mm） and degree of primary particles （d 〈0.01 mm） aggregation were closely related to the concentrations of total soil organic carbon, and loosely and tightly combined organic carbon in heavy fraction. Soil microaggregation could be associated with organic carbon concentration and its combined forms in heavy fraction. There was a direct relationship between microaggregation and macroaggregation of soil primary particles, because the contents of wet aggregates 〉 0.25 mm and its water stability of aggregates were highly correlated with the contents of aggregated primary particle （d 〈 0.01 mm） and the degree of primary particles （d 〈 0.01 mm） aggregation.
文摘Well-aggregated soil has been shown to improve soil infiltration and reduce runoff and soil erosion, making well-aggregated soil important for productive, sustainable agriculture. One factor that may influence near-surface soil aggregate stability is fertilizer application. Rapid dissolution of fertilizers, which are mostly salts, can potentially disperse clays and destabilize aggregates. The objective of this study was to evaluate the potential effect of various fertilizer-phosphorus (P) and -nitrogen (N) sources [i.e., triple superphosphate (TSP), monoammonium phosphate (MAP), chemically precipitated struvite (CPST), electrochemically precipitated struvite (ECST), environmentally smart nitrogen (ESN)] and soil depth on water-stable aggregates (WSA) in furrow-irrigated rice on a silt-loam soil (Typic Albaqualf). Total WSA (TWSA) concentration was unaffected (P > 0.05) by fertilizer treatment or soil depth, while WSA concentration was numerically largest (P ∙g<sup>-1</sup>), which did not differ from CPST, ECST, and ESN in the 0 - 5 cm depth or the unamended control in the 0 - 5 and 5 - 10 cm depths, and was at least 1.7 times larger than ESN in the 5 - 10 cm depth (0.03 g∙g<sup>-1</sup>). Results indicated that WSA concentration among non-struvite fertilizer-P sources was generally similar to that from the struvite fertilizer materials. Principal component analysis determined that 32% of the variation of TWSA was mainly explained by changes in soil bulk density, pH, and electrical conductivity. Long-term, continual annual application of fertilizer-P and N could negatively impact soil aggregate stability, soil structure, and potentially erosion.
基金supported by the National Key R&D Program of China(No.2021YFD1900901)the National Natural Science Foundation of China(No.32271711).
文摘Nitrogen(N)loss is a major limiting factor affecting agricultural productivity in saline-alkali soils,with ammonia(NH_(3))volatilization and N leaching being the main sources of N loss.In this study,the dynamics of NH_(3)volatilization were measured using the open static chamber method(sponge sampling),alongside the distribution of^(15)N and NO_(3)^(-)-N concentrations in layers,in a 30-cm soil column experiment with vermicompost addition after incorporation of^(15)N-labeled urea in the upper layer(0-10 cm)of a saline-alkali soil.Destructive sampling was conducted on days 20 and 60 of the column experiment to investigate the influencing factors of NH_(3)volatilization and^(15)N/NO_(3)^(-)retention,respectively.The results showed that the addition of vermicompost to saline-alkali soil decreased cumulative NH_(3)volatilization by 45.1%,decreased the^(15)N concentration in the bottom layer(20-30 cm)by 17.1%,and increased the^(15)N concentration in the upper soil by 48.7%.Vermicompost regulated the abundances of amoA,amoC,and nxrA genes,which can decrease NH_(3)volatilization by converting substrate NH_(4)^(+)to NO_(3)^(-).Additionally,Ca^(2+)adsorption is enhanced(increased by 6.2%)by increasing soil cation exchange capacity(increased by 20.6%),thus replacing the adsorption of Na^(+)(decreased by 13.8%)and decreasing the desorption of NH_(4)^(+).Vermicompost enhanced the adsorption of NO_(3)^(-)by increasing Ca^(2+)and Mg^(2+)and decreasing Cl-by 30.4%in the upper soil.This study concluded that vermicompost addition can inhibit N loss by reducing NH_(3)volatilization and improving^(15)N/NO_(3)^(-)retention in saline-alkali soils.
基金supported by the Shenyang Municipal Science and Technology Project,China(23-409-2-03)the Liaoning Provincial Department of Science and Technology Project,China(Z20230183)the Liaoning Provincial Applied Basic Research Program,China(2022JH2/101300173).
文摘Both soil organic carbon (SOC) and iron (Fe) oxide content, among other factors, drive the formation and stability of soil aggregates.However, the mechanism of these drivers in greenhouse soil fertilized with organic fertilizer is not well understood.In a 3-year field experiment, we aimed to investigate the factors which drive the stability of soil aggregates in greenhouse soil.To explore the impact of organic fertilizer on soil aggregates, we established four treatments:no fertilization (CK);inorganic fertilizer (CF);organic fertilizer (OF);and combined application of inorganic and organic fertilizers(COF).The application of organic fertilizer significantly enhanced the stability of aggregates, that is it enhanced the mean weight diameter, geometric mean diameter and aggregate content (%) of>0.25 mm aggregate fractions.OF and COF treatments increased the concentration of SOC, especially the aliphatic-C, aromatic-C and polysaccharide-C components of SOC, particularly in>0.25 mm aggregates.Organic fertilizer application significantly increased the content of free Fe(Fed), reactive Fe (Feo), and non-crystalline Fe in both bulk soil and aggregates.Furthermore, non-crystalline Fe showed a positive correlation with SOC content in both bulk soil and aggregates.Both non-crystalline Fe and SOC were significantly positively correlated with>2 mm mean weight diameter.Overall, we believe that the increase of SOC, aromatic-C, and non-crystal ine Fe concentrations in soil after the application of organic fertilizer is the reason for improving soil aggregate stability.
基金the Fundamental Research Funds for the Central Universities(Grant No.2572021DT04)the National Natural Science Foundation of China(Grant No.31770656).
文摘Nitrogen and phosphorus (NP) deposition can change the nutrient input of forest ecosystems. The effects of NP deposition on soil aggregate need to be analyzed to propose effective environmental management strategies. In this study, representative Korean pine mixed forests and Korean pine plantations in northeastern China were selected. Soil samples were sieved to obtain four different particle sizes of soil aggregates (> 2, 2–0.25, 0.25–0.053, and < 0.053 mm). Four NP treatments were applied to simulate N and P deposition, and an indoor incubation experiment was conducted over a period of 360 d. Total nitrogen, microbial nitrogen, dissolved organic nitrogen, hydrolyzed nitrogen, NH_(4)^(+)–N, NO_(3)^(−)–N content, and extracellular enzyme activities of NAG, LAP, and AP were determined. Different fractions of N responded differently to NP addition. Lower NP addition had a greater promoting effect on aggregate N compared to higher NP addition. NAG was the main extracellular enzyme affecting N in both forest types. NP addition had a greater effect on the extracellular enzyme activities of the soil aggregates from the Korean pine plantations. These results enhance our understanding of the effects of NP addition on soil nitrogen within temperate forest ecosystems.
基金supported by the National Natural Science Foundation of China(41672342)Natural Science Foundation of Sichuan Province(2024NSFSC0101).
文摘Soil aggregate plays a critical role in the sequestration of soil organic carbon(SOC)on the Qinghai-Tibetan Plateau(QTP).However,the impact of plateau pika(Ochotona curzoniae)on these processes remains uncertain.In this study,we examined both control and pika disturbed alpine grasslands across various degradation levels,including undegraded(UDM),lightly(LDM),moderately(MDM)and severely(SDM)degraded sites.Through analyzing variations in aggregate size distribution,stability,aggregate associated SOC(ASOC)and bulk SOC(BSOC)concentration,we investigated the influence of plateau pika disturbance on SOC,and compared these effects across varying degradation levels.The results indicate that:(i)pika disturbance decreases soil water content(SWC)by 26.3%and 22.2%in LDM and SDM at the surface soil layer,while increasing SWC by 34.1%and 30.4%in LDM and MDM at the subsurface soil layer.It significantly reduces bulk density(BD)across all soil depths and grassland types,with most significant effect in LDM;(ii)Plateau pika disturbance increases the macroaggregate proportion in both drysieved aggregate(DSA)and water-stable aggregate(WSA),particularly in LDM.It enhances mean weight diameter(MWD)and geometric mean diameter(GMD)for both DSA and WSA,especially in MDM;(iii)Pika disturbance mitigates the negative effect of soil properties on aggregate stability,particularly in LDM and MDM,thereby enhancing the positive effect of aggregate stability on ASOC and improving BSOC content,especially in LDM.These findings provide novel insights into the effects of plateau pika disturbance on SOC dynamics in alpine grasslands.
基金jointly supported by the Key Research and Development Program of Shandong Province,China(LJNY202103 and 2023TZXD086)the National Major Agricultural Science and Technology Project,China(NK202218080315)+1 种基金the Project of Central Government Guiding Local Science and Technology Development,China(YDZX2022130)the Cooperative Promotion Plan of Major Agricultural Technologies of Shandong Province,China(SDNYXTTG-2023-10)。
文摘Integrated agronomic optimization(IAO)adopts suitable crop varieties,sowing dates,planting density,and advanced nutrient management to redesign the entire production system according to the local environment,and it can achieve synergistic improvements in crop yields and resource utilization.However,the intensity and magnitude of the impacts of IAO on soil quality under long-term intensive production and high nitrogen use efficiency(NUE)require further clarification.Based on a 13-year field experiment conducted in Dawenkou,Tai'an,Shadong Province,China,we investigated the effects of four cultivation modes on the grain yield,NUE,and soil aggregate structure,as well as the fraction of organic matter(SOM)and soil quality,reflected by the integrated fertility index(IFI),during the winter wheat maturation periods in 2020–2022.The four cultivation modes were traditional local farming(T1),farmer-based improvement(T2),increased yield regardless of production cost(T3),and integrated soil–crop system management(T4).As the IAO modes,T2 and T4 were characterized by denser planting,reduced nitrogen(N)fertilizer application rates,and delayed sowing compared to T1 and T3,respectively.In this long-term experiment,IAO was found to maintain aggregate stability,increase SOM content(by increasing organic carbon and total nitrogen of the light fraction(LF)and the particulate organic matter fraction(POM)),and improve SOM quality(by increasing the proportions of LF and POM and the ratio of organic carbon to total nitrogen in SOM).Compared to T1,the IFI values of T2,T3,and T4 increased by 10.91,23.38,and 25.55%,and by 17.78,6.41,and 28.94%in the 0–20 and 20–40 cm soil layers,respectively.The grain yield of T4 was 22.52%higher than that of T1,and reached 95.98%of that in T3.Furthermore,the NUE of T4 was 35.61%higher than those of T1 and T3.In conclusion,our results suggest that the IAO mode T4 synergistically increases grain yield and NUE in winter wheat,while maximizing soil quality.
基金financially supported by the National Key Research and Development Program of China(2023YFD1901200)the National Natural Science Foundation of China(U22A20562)+4 种基金the Sichuan Science and Technology Program,China(2022YFS0500)the Project of Special Research Assistant of the Chinese Academy of Sciences(Jing Zheng)the China Postdoctoral Science Foundation(2022M723079)the Sichuan Provincial Postdoctoral Research Foundation,China(TB2022042)the Science and Technology Research Program of Institute of Mountain Hazards and Environment,Chinese Academy of Sciences(IMHEZYTS-08)。
文摘Crop straw incorporation is widely recommended to maintain crop yields and improve soil organic carbon(SOC)stocks as well as soil quality.However,the long-term effects of different straw incorporation practices on the SOC stock remain uncertain.In this study,a long-term experiment(2007 to 2018)with four treatments(MW_0:maize–wheat rotation with no straw incorporation,MW_(50):maize–wheat rotation with 50%chopped straw incorporation,MW_(b50):maize–wheat rotation with 50%in situ burned harvested straw,and MF_(50):maize–fallow rotation with 50%harvested maize straw incorporation)was set up to evaluate the response of the SOC stock to different straw incorporation methods.The results showed that the SOC stock significantly increased by 32.4,12.2 and 17.4%under the MW_(50),MW_(b50)and MF_(50)treatments,respectively,after continuous straw incorporation over a decade,while the SOC stock under MW0 was significantly reduced by 22.9%after the 11 year long-term experiment.Compared to MW_0,straw incorporation significantly increased organic carbon input,and improved the soil aggregate structure and the ratio of dissolved organic carbon(DOC)to particulate organic carbon(POC),but it did not significantly stimulate soil heterotrophic respiration,resulting in the increased SOC accumulation rate and SOC stocks of bulk soil.The increased ratio of DOC to microbial biomass carbon(MBC)enhanced the relative abundances of Acidobacteria and Proteobacteria but inhibited Bacteroidetes and Chloroflexi,and the bacterial relative abundances were the main reasons for the non-significant increase or even decrease in soil heterotrophic respiration with straw incorporation.The SOC stock would reach an equilibrium based on the results of Rothamsted carbon(RothC)model simulations,with a long-term equilibrium value of 18.85 Mg ha^(–1)under MW_(50).Overall,the results of the long-term field experiment(2007–2018)and RothC model simulation suggested that maize–wheat rotation with 50%chopped straw incorporation delivered the largest benefits for the SOC stock in calcareous soils of subtropical mountain landscapes over the long term.
基金supported by the National Natural Science Foundation of China(NO.32201626)the Key Research and Development Program of Jiangxi Province(20223BBG74S01,20223BBG71013).
文摘In response to the effectiveness of reforestation in controlling soil erosion,there has been a dramatic increase in forest coverage in the hilly red soil region of southern China.Aggregate stability and soil shear strength are indicators that reflect soil resistance to erosion and its ability to prevent shallow landslides,respectively.However,limited research has focused on the response of soil aggregate stability and shear strength to reforestation.We selected three types of reforestations(Phyllostachys edulis forest,Cunninghamia lanceolata(Lamb.)Hook.forest,Citrus sinensis(L.)Osbeck.orchard),a natural forest(mixed coniferous and broadleaf forests),and a fallow land as study plots,and measured root traits,and soil physicochemical traits,i.e.,pH,soil organic matter(SOC),Soil water content(SWC),soil bulk density(BD),soil cohesion(c),soil internal friction angle(φ)and analyzed their multiple interactions.The soil aggregate stability traits,refer to the mean weight diameter(MWD)and geometric mean diameter(GMD),exhibited a significant increase in reforested plots,approximately 200%compared to fallow land and 50%compared to natural forests.For soil shear strength the values were approximately 20%higher than in fallow land and approximately 10%lower than in natural forests.Soil aggregate stability and soil shear strength did not exhibit a significant positive correlation across all plots,and the underlying drivers of these traits were variable.For instance,in natural forest and timber stands,soil aggregate stability was mainly influenced by soil organic carbon,while soil shear strength was primarily affected by root length density.In economic forest,aggregate stability and shear strength are mainly affected by organic carbon.Overall,we found that vegetation restoration enhances soil erosion resistance,however,the primary drivers for the improvement of aggregate stability(soil organic carbon)and shear strength(root length density)are different.Therefore,in future benefit assessments of vegetation restoration projects aimed at soil erosion control,different indicators should be considered based on specific conditions.
基金This research was supported by the Program for Guangdong Introducing Innovative and Enterpreneurial Teams(2019ZT08L213)Youth Program of National Natural Science Foundation of China(42007013)Guangdong Basic and Applied Basic Research Foundation(2019A1515110777).
文摘Soil aggregation is one of the crucial processes that facilitate carbon sequestration and maintain soil fertility.So far,the effect of biochar amendment on soil aggregation remains inconclusive.Here,we tested the hypothesis that the response of soil aggregation to biochar addition varied with incubation duration and biochar chemistry.A one year microcosm experiment of soil with biochar was conducted that included biochar produced at three different temperatures(300,450,and 600°C),and three biochar application rates,i.e.,0,1,and 3 wt%.It was observed that after one and three months,biochar mainly(>90%)distributed in the micro-aggregates,and slightly reduced aggregate stability and increased proportion of micro-aggregates,which was demonstrated to result from the mechanical mixture of amended biochar with soil.Contrastingly,when the duration was prolonged to six months and one year,a significant increase in macro-aggregates(6.6-38.5%)and aggregate stability(7.3-29.4%)was detected,with the increasing extent being apparently higher for low-temperature biochar.This was related to the comparatively strong interaction of biochar particles with soil minerals or microbes after long-time incubation.The strong interaction was directly supported by the significant increase in H/C,O/C ratios of isolated biochar from treated soils,the detection of typical soil mineral elements on the surface of isolated biochar,and the increase in microbial biomass carbon of treated soils.The findings of this study highlighted the role of biochar type and amendment duration in mediating the effect of biochar application on soil aggregation.
基金financially funded by the National Natural Science Foundation of China(Nos.U23A2054 and 42377128)the National Key R&D Program of China(No.2022YFD1901300)。
文摘Soil health is an important component of“One Health”.Soils provide habitat to diverse and abundant organisms.Understanding microbial diversity and functions is essential for building healthy soils towards sustainable agriculture.Arbuscular mycorrhizal fungi(AMF)form potentially symbiotic associations with approximately 80%of land plant species that are well recognized for carbon flux and nutrient cycling.In addition to disentangling the signaling pathways and regulatory mechanisms between the two partners,recent advances in hyphosphere research highlight some emerging roles of AMF and associated microbes in the delivery of soil functions.This paper reviews the contribution of AMF to soil health in agroecosystems,with a major focus on recent progress in the contribution of hyphosphere microbiome to nutrient cycling,carbon sequestration,and soil aggregation.The hyphosphere microbiome and fungal stimulants open avenues for developing new fertilizer formulas to promote AMF benefits.In practice,developing AMF-friendly management strategies will have long-term positive effects on sustainable agriculture aiming at simultaneously providing food security,increasing resource use efficiency,and maintaining environment integrity.
基金the National Natural Sciences Foundation of China(41807060,41977061)National Special Research and Development Project during the Thirty Five-year Plan Period(2017YFC0504702).
文摘Soil aggregate fractions can regulate microbial community composition and structure after vegetation restoration.However,there has been less focus on the effects of soil aggregate fractions on the distributions of microbial communities.Here,we used phospholipid fatty acid(PLFA)analysis to explore the effects of different years of vegetation restoration(a 35-year-old Thymus mongolicus community(Re-35yrs)and a 2-year-old nongrazing grassland(Ug-2yrs))on microbial communities within different soil aggregate sizes(<0.25 mm,0.25–1 mm,1–2 mm,2–3 mm,3–5 mm and>5 mm).The results indicated that the amount of total PLFA in Re-35yrs was 10 times greater than that in Ug-2yrs.The soil aggregate stability increased with increasing duration of vegetation restoration.In Re-35yrs,the total PLFA shown an increase as the soil aggregate size increased,and the highest values were observed in 3–5 mm.Ug-2yrs differed from Re-35yrs,the soil microbial diversity was higher in medium particle sizes(1–2 mm and 2–3 mm)and lower in microaggregates(<0.25 mm and 0.25–1 mm)and macroaggregates(3–5 mm and>5 mm).Soil microbial diversity was highest in large particle size aggregates,which resulted in low environmental stress and strong stability.The same tendency was observed in the high values of cyc/prec,S/M and soil organic matter,which indicated a lower turnover speed(F/B)of fungal energy utilization and a higher fixation rate.After years of natural restoration,the soil microbial community generally transformed from nutrient-rich to heterotrophdominant,especially in microaggregates(reflected in the G^(+)/G^(–)ratio).
基金financially supported by the Joint Funds of the National Natural Science Foundation of China(U22A20609)the National Key Research and Development Program of China(2021YFD1901102-4)+2 种基金the State Key Laboratory of Integrative Sustainable Dryland Agriculture(in preparation)the Shanxi Agricultural University,China(202003-3)the Open Fund from the State Key Laboratory of Soil Environment and Nutrient Resources of Shanxi Province,China(2020002)。
文摘Tillage practices during the fallow period benefit water storage and yield in dryland wheat crops.However,there is currently no clarity on the responses of soil organic carbon(SOC),total nitrogen(TN),and available nutrients to tillage practices within the growing season.This study evaluated the effects of three tillage practices(NT,no tillage;SS,subsoil tillage;DT,deep tillage)over five years on soil physicochemical properties.Soil samples at harvest stage from the fifth year were analyzed to determine the soil aggregate and aggregate-associated C and N fractions.The results indicated that SS and DT improved grain yield,straw biomass and straw carbon return of wheat compared with NT.In contrast to DT and NT,SS favored SOC and TN concentrations and stocks by increasing the soil organic carbon sequestration rate(SOCSR)and soil nitrogen sequestration rate(TNSR)in the 0-40 cm layer.Higher SOC levels under SS and NT were associated with greater aggregate-associated C fractions,while TN was positively associated with soluble organic nitrogen(SON).Compared with DT,the NT and SS treatments improved soil available nutrients in the 0-20 cm layer.These findings suggest that SS is an excellent practice for increasing soil carbon,nitrogen and nutrient availability in dryland wheat fields in North China.
基金supported by the National Natural Science Foundation of China(Nos.41930756 and 42077041)Fujian Provincial Natural Science Foundation of China(No.2020J01187)。
文摘The conversion of natural forests in subtropical regions to plantations or secondary forests has resulted in alterations in soil variables,microbial communities,and microbially mediated processes,including nitrous oxide(N_(2)O)emissions.However,how forest conversion influences soil N_(2)O reduction and the abundance and community structure of N_(2)O-reducing microorganisms remains unclear.Here,we investigated the impact of converting natural forests to a secondary forest and Cunninghamia lanceolata and Pinus massoniana plantations on the abundance and community structure of N_(2)O-reducing microorganisms in both bulk soils and soil aggregates.Compared with the secondary forest,plantations had higher soil pH and available phosphorus and moisture contents,lower soil NH_(4)^(+)content,but similar aggregate sizes.Compared with the secondary forest,the conversion of natural forest to plantations resulted in significantly higher soil N_(2)O reduction rate and increased abundances of nosZⅠand nosZⅡgenes in bulk soils and soil aggregates.The abundance of nosZⅠwas higher than that of nosZⅡin all tested soils and had a stronger association with N_(2)O reduction rate,suggesting the greater role of nosZⅠ-carrying microorganisms in N_(2)O consumption.Forest conversion had a greater impact on the community composition of nosZ I than nosZⅡ,mainly by increasing the relative abundances of alpha-and beta-Proteobacteria,while decreasing gamma-Proteobacteria.However,nosZⅡ-carrying microorganisms were exclusively dominated by Gemmatimonadetes and less affected by forest conversion.Taken together,our findings significantly contribute to our understanding of the eco-physiological characteristics of N_(2)O-reducing microorganisms and highlight the importance of nosZⅠ-carrying microorganisms in N_(2)O consumption in subtropical forest soils.
基金co-funded by the National Natural Science Foundation of China(U204020742277323)+2 种基金the 111 Project of Hubei Province(2021EJD026)the open fund of Key Laboratory of Geological Hazards on Three Gorges Reservoir Area(China Three Gorges University)Ministry of Education(2022KDZ24).
文摘Soil aggregate is the basic structural unit of soil,which is the foundation for supporting ecosystem functions,while its composition and stability is significantly affected by the external environment.This study was conducted to explore the effect of external environment(wetting-drying cycles and acidic conditions)on the soil aggregate distribution and stability and identify the key soil physicochemical factors that affect the soil aggregate stability.The yellow‒brown soil from the Three Gorges Reservoir area(TGRA)was used,and 8 wetting-drying conditions(0,1,2,3,4,5,10 and 15 cycles)were simulated under 4 acidic conditions(pH=3,4,5 and 7).The particle size distribution and soil aggregate stability were determined by wet sieving method,the contribution of environmental factors(acid condition,wetting-drying cycle and their combined action)to the soil aggregate stability was clarified and the key soil physicochemical factors that affect the soil aggregate stability under wetting-drying cycles and acidic conditions were determined by using the Pearson’s correlation analysis,Partial least squares path modeling(PLS‒PM)and multiple linear regression analysis.The results indicate that wetting-drying cycles and acidic conditions have significant effects on the stability of soil aggregates,the soil aggregate stability gradually decreases with increasing number of wetting-drying cycles and it obviously decreases with the increase of acidity.Moreover,the combination of wetting-drying cycles and acidic conditions aggravate the reduction in the soil aggregate stability.The wetting-drying cycles,acidic conditions and their combined effect imposes significant impact on the soil aggregate stability,and the wetting-drying cycles exert the greatest influence.The soil aggregate stability is significantly correlated with the pH,Ca^(2+),Mg^(2+),maximum disintegration index(MDI)and soil bulk density(SBD).The PLS‒PM and multiple linear regression analysis further reveal that the soil aggregate stability is primarily influenced by SBD,Ca^(2+),and MDI.These results offer a scientific basis for understanding the soil aggregate breakdown mechanism and are helpful for clarifying the coupled effect of wetting-drying cycles and acid rain on terrestrial ecosystems in the TGRA.
基金supported financially by the National Natural Science Foundation of China(41807102,U1710255-3 and 41907215)the Special Fund for Science and Technology Innovation Teams of Shanxi Province,China(202304051001042)the Distinguished and Excellent Young Scholar Cultivation Project of Shanxi Agricultural University,China(2022YQPYGC05)。
文摘We studied changes in the concentrations of aggregate-cementing agents after different reclamation times and with different fertilization regimes,as well as the formation mechanism of aggregates in reclaimed soil,to provide a theoretical basis for rapid reclamation of soil fertility in the subsidence area of coal mines in Shanxi Province,China.In this study,soil samples of 0–20 cm depth were collected from four fertilization treatments of a longterm experiment started in 2008:no fertilizer (CK),inorganic fertilizer (NPK),chicken manure compost (M),and50%inorganic fertilizer plus 50%chicken manure compost (MNPK).The concentrations of cementing agents and changes in soil aggregate size distribution and stability were analysed.The results showed that the formation of>2 mm aggregates,the aggregate mean weight diameter (MWD),and the proportion of>0.25 mm water-stable aggregates (WR_(0.25)) increased significantly after 6 and 11 years of reclamation.The concentration of organic cementing agents tended to increase with reclamation time,whereas free iron oxide (Fed) and free aluminium oxide(Ald) concentrations initially increased but then decreased.In general,the MNPK treatment signi?cantly increased the concentrations of organic cementing agents and CaCO_(3),and CaCO_(3) increased by 60.4%at 11 years after reclamation.Additionally,CaCO_(3) had the greatest effect on the stability of aggregates,promoting the formation of>0.25 mm aggregates and accounting for 54.4%of the variance in the proportion and stability of the aggregates.It was concluded that long-term reclamation is bene?cial for improving soil structure.The MNPK treatment was the most effective measure for increasing maize grain yield and concentration of organic cementing agents and CaCO_(3).
