查看更多>>摘要：·Response of growth rate and antioxidative system of ten Bacillus strains to acid stresses was assayed.·Strong acid treatment significantly decreased the growth rate of the strains.·Acid stresses increased the GPX activity and GSSG content of the tested strains.·Divergent changes occurred in ROS and antioxidative system(SOD,CAT,GR,MDA and GSH).Environmental changes including soil acidification exert obvi-ous stresses on soil ecosystems and influence soil microor-ganisms.In this study,ten microbial strains were incubated under different acid treatments to investigate responses of microbial growth and antioxidative system to acid stress.All the strains belong to Bacillus genus,but exhibit distinct ecological functions.We observed that these microbial strains had obviously different pH tolerance threshold,in spite of the close phylogenetic classification among strains.Acid stresses exerted significant effects on microbial antiox-idative system,including superoxide dismutase(SOD),cata-lase(CAT)and glutathione transferring enzymes(GPX and GR)and reactants(GSH and GSSH),but the effects were strain specific.Furthermore,we found acid stress effects on total variances of the investigated microbial antioxidative system along the first two principal components(PCs).Activities of CAT and SOD contributed substantially to PC1 that reflected obvious acid effects on NC7 and ZC4,and closely related to intracellular malondialdehyde content.The GSSG activities and GSH/GSSG contributed greatly to PC2 that unveiled acid stress effects on most of the microbial strains.Our results highlight substantially heterogeneous responses of microbial strains to acid stress and support that phylogenetic closeness does not imply functional similarity of soil microorganisms under environmental changes.
查看更多>>摘要：·Integrated grain cropping systems promote soil health(SH)and sustainability.·Microbial biomass and activity(MBA)and community structure(MCS)are key to SH.·Integration of maize with Urochloa pastures strongly impacts MBA and MCS.·MBA is more sensitive than MCS to shifts in grain cropping systems.·Systems under continuous Urochloa increased microbial activity and AMF abundance.Tropical soils are prone to degradation.Adoption of conservation agricultural practices is essential to improve soil health,which is influenced by soil microbes.In this study we analyzed shifts in microbial biomass and activity(MBA)and microbial community structure(MCS)based on fatty acid methyl esthers(FAMEs)between five no-till agricultural practices:maize monoculture(MM);maize annualy intercropped with Urochloa decumbens(M/Ud);M/Ud with soybean rotation every other year(M/Ud-S);M/Ud keeping the pasture for the next two years(M/Ud-Ud-Ud);and maize intercropped with U.ruziziensis keeping the pasture for the next two years(M/Ur-Ur-Ur).Results indicated that MBA was affected by the inclusion of Urochloa intercropping and by rotation with soybean.Systems under a longer residence time with Urochloa in the field had higher β-glucosidase activity and soil basal respiration,indicating a greater microbial activity.MCS was less affected than MBA by the investigated cropping systems.MCS changed only in the continuous pasture systems,which were enriched in arbuscular mycorrhyzal fungi(AMF).Additionally,the continuous pasture systems had lower microbial stress ratios than the other agricultural practices.In sum,our study showed that utilization of Urochloa spp.under longer periods in no-till agricultural practices contributes to increase microbial activity,AMF abundance and decrease microbial stress ratio.These changes are primarily beneficial for soil health.
Khoa Phuc NguyenTan Trong TranHuy Dinh LePhuong Thuy Nguyen...
131-140页
查看更多>>摘要：·Land use type affects the physicochemical properties of soil.·The value of OM and TN is high in acacia soils.·Strong acidity of soil is considered a serious constraint for agriculture.·Suitable cash crops are acacia,cassava,banana,rice and maize.Soil fertility is affected by land-use types and land management,which exacerbates soil erosion and various other forms of soil degradation in the mountainous regions of Viet-nam.This study was conducted in A Luoi District,Thua Thien Hue,Vietnam to identify the effects of land-use types on specific soil physicochemical characteristics related to soil fertility.Soil physicochemical properties,such as organic matter(OM),total nitrogen(TN),total phosphorous(TP),and K+were significantly affected by land-use type.The results showed that the soils were sandy in rice but clay loam for acacia and cassava.The mean bulk density value of acacia soil was significantly greater than that of other soils.TN were higher in the acacia soils than those in the rice,maize,and banana soils.The OM content was significantly higher in the acacia,cassava,and banana soils than those in the rice and maize soils.The mean of exchangeable K+in the rice soil was higher compared to those in other soils and was affected by land-use type.The high exchangeable acidity content in the soils was probably due to intensive precipitation.However,both land use type and management did not affect the CEC value.Overall,the inappropriate land use caused the disturbance of soil physicochemical properties,indicating that the conditions of rice and maize soils are becoming worse than acacia soils.Therefore,lowering the intensity of cultivation,adopting incorporated soil fertility management,and applying organic fertilizer should preserve the existing conditions and enhance soil properties.
查看更多>>摘要：·Flue gas desulfurization gypsum and clover planting alleviated the soil salinization stress.·Soil pH and total phosphorus affected the bacterial communi-ties.·Total phosphorus affected the fungal communities.·Flue gas desulfurization gypsum and clover planting improved jujube quality.The coastal area of Shandong Province,characterized by coastal saline tidal soil,is one of the main production areas of winter jujube in China.However,the low soil fertility and poor soil structure in jujube orchard restricted the development of the jujube industry.The objectives of this study were to 1)evaluate the effect of application of flue gas desulfurization(FGD)gypsum and clover planting on soil quality improvement and soil microbial community structure of jujube orchard;2)investigate the effects of two measures on the nutrition and quality of winter jujube.The results showed that FGD gypsum reduced the soil total salt content by 65.6％,and clover planting increased the soil organic matter content by 30.7％,which effectively alleviated the soil salinization stress and improved the soil structure.Soil pH and total phosphorus(TP)were the main determinants influencing bacterial community composition,and TP was the dominant factor of the fungal community composition in the saline-alkali soils.Meanwhile,FGD gypsum addition and clover planting significantly increased the sugar degree and Vc content of winter jujube,thus improved jujube quality,and further contributed to the ecological sustainable development of winter jujube industry.
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