[Objectives]In response to the issue of soil improvement in Yuanmou County,the effects of combined application of biochar-based organic fertilizer and reduced nitrogen fertilizer on soil nutrients,soil enzyme activity...[Objectives]In response to the issue of soil improvement in Yuanmou County,the effects of combined application of biochar-based organic fertilizer and reduced nitrogen fertilizer on soil nutrients,soil enzyme activity,and yield of purple cabbage(Brassica oleracea var.capita rubra)were investigated in the field base of Institute of Thermal Zone Ecological Agriculture,Yunnan Academy of Agricultural Sciences in Yuanmou County.[Methods]A total of 13 treatments were set up by applying biochar-based organic fertilizer at three levels of 15,30 and 45 t/hm^(2)(T_(1),T_(2),T_(3)),combined with top application of nitrogen fertilizer(urea)at four levels:375(N_1),300(N_(2)),225(N_(3))and 0 kg/hm^(2),with non-fertilizing treatment as control check(CK),in order to explore the optimal ratio for the combined application of biochar-based organic fertilizer with nitrogen fertilizer.[Results]The application of biochar-based organic fertilizer could significantly improve soil nutrients,enzyme activity,and purple cabbage yield.The improvement effect of combined application with nitrogen fertilizer was higher than that of single application of biochar-based organic fertilizer,and the improvement effect was enhanced with the application amount of biochar-based organic fertilizer increasing.The contents of organic matter and total nitrogen were the highest in treatment T_(3)N_(3),of which the values increased by 81.39%and 56.09%compared with the CK,respectively.The contents of soil hydrolyzable nitrogen,available phosphorus,and available potassium were all the highest under treatment T_(3)N_(2),with increases of 92.76%,171.01%and 235.50%,respectively.There was a significant positive correlation between the activity of soil catalase,urease,and sucrase and organic matter,total nitrogen,and available nutrients.The overall soil enzyme activity was relatively higher in treatment T_(3)N_(2).The yield of purple cabbage treated with biochar-based organic fertilizer combined with nitrogen fertilizer could reach 85750 kg/hm^(2),which was 94.78%higher than that treated with biochar-based organic fertilizer alone.Based on comprehensive analysis,the optimal combination ratio was 45 t/hm^(2)of biochar-based organic fertilizer and 300 kg/hm^(2)of urea(T_(3)N_(2)).[Conclusions]This study provides data support for the promotion of biochar-based organic fertilizers and reduced fertilizer in agricultural soil in the Dam area of Yuanmou County.展开更多
[Objectives]This study was conducted to evaluate the effects of carbon nanomaterials on soil ecosystem and explore the ecological risks of environmental exposure of carbon nanomaterials. [Methods] The effects of carbo...[Objectives]This study was conducted to evaluate the effects of carbon nanomaterials on soil ecosystem and explore the ecological risks of environmental exposure of carbon nanomaterials. [Methods] The effects of carbon nanomaterials on soil enzyme activity was studied by adding graphene, graphene oxide and carbon nanotubes to turfgrass soil. [Results] Compared with the control(CK), the activity of soil protease, sucrase, alkaline phosphatase and catalase was not significantly affected by carbon nanomaterials. Under the treatment of carbon nanotubes, urease activity was significantly lower than that of graphene and graphene oxide, and dehydrogenase activity was significantly lower than that of the CK, graphene and graphene oxide. [Conclusions] This study provides a theoretical basis for the safe application of carbon nanomaterials.展开更多
[Objectives]This study was conducted to reveal the effects of bamboo charcoal-based biochar(or bamboo charcoal for short)on soil enzyme activity and microbial community structure.[Methods]The field experiment was carr...[Objectives]This study was conducted to reveal the effects of bamboo charcoal-based biochar(or bamboo charcoal for short)on soil enzyme activity and microbial community structure.[Methods]The field experiment was carried out at the Modern Agriculture Demonstration Base of Gaoping Village,Gaoping Town,Suichang County,Zhejiang Province.Bamboo charcoal was applied at four different levels:T_(0)(no bamboo charcoal),T_(1)(1125 kg/hm^(2)bamboo charcoal),T_(2)(2250 kg/hm^(2)bamboo charcoal)and T_(3)(3375 kg/hm^(2)bamboo charcoal).Soil physicochemical properties and enzyme activities in different treatments were measured.[Results]The soil fungal,bacterial and actinomycete populations increased significantly in the soils surrounding capsicum roots.The bacterial population,fungal population and fungus/bacterium ratio peaked in Treatment T_(2),up to 7.32×10^(6)cfu/g,2.65×10^(4)cfu/g and 0.36×10^(-2),respectively.The effect of bamboo charcoal in promotingβ-glucoside,catalase,acid phosphatase and sucrase activities was T_(2)>T_(3)>T_(1)>T_(0).With bamboo charcoal increasing,the bacterium population,fungus population,fungus/bacterium ratio,β-glucoside,catalase,acid phosphatase and sucrase activities all increased at first and then decreased.T_(2)treatment showed the best effects in improving soil physicochemical properties and microbial community structure.[Conclusions]Bamboo charcoal significantly improves soil enzyme activity and increases soil microbial population,and thus has important positive effects on the soil ecosystem.展开更多
[Objectives]This study was conducted to investigate the effects of Vitis heyneana cultivation on rocky hillsides on the variation of soil fertility,so as to provide theoretical support for economic development and the...[Objectives]This study was conducted to investigate the effects of Vitis heyneana cultivation on rocky hillsides on the variation of soil fertility,so as to provide theoretical support for economic development and the control of rocky desertification in the Dashi mountainous area.[Methods]Taking V.heyneana planting base in Luocheng County,Hechi City,Guangxi Province as the research object,the methods of field investigation,regular sampling and experimental analysis were used to analyze seasonal variations of soil urease,sucrase and soil alkaline phosphatase activity of 15 different sample plots surveyed,and their correlation with soil physical and chemical properties was analyzed.[Results]①In general,sucrase,urease and alkaline phosphatase were lower in summer and autumn,and higher in spring and winter,and the performance of the activity of the three enzymes was inconsistent.Among them,the activity of sucrase was in order of spring>autumn>summer>winter,and the activity of urease and alkaline phosphatase showed an order of winter>spring>summer>autumn.②The seasonal variations of soil fertility in different sample plots were affected by various factors such as human disturbance,climate change,vegetation coverage,topography and landforms,cultivation and management measures,and although the change laws in different sample plots were different,the seasonal differences in soil fertility in the same place were extremely significant.③If the influence of artificial fertilization factors is excluded,the planting of V.heyneana on rocky hillsides will cause a significant decrease in soil enzyme activity,that is,a significant decrease in soil fertility.[Conclusions]Related issues such as the effects of planting V.heyneana on the variation of soil fertility in rocky hillsides should arouse necessary attention of management departments and producers.展开更多
The experiment was conducted to study the impact of application of microbial inoculants, compared with no microbial fertilizer, on enzyme activity, microbial biomass and available nutrient contents in paddy soil in He...The experiment was conducted to study the impact of application of microbial inoculants, compared with no microbial fertilizer, on enzyme activity, microbial biomass and available nutrient contents in paddy soil in Heilongjiang Province. The application of soil phosphorus activator was able to increase the quantity of bacteria and fungi in soil, but its effect on actinomycetes in soil was not significant. The application of microbial inoculants increased the urease and sucrase activities in soil over the growing season, but only at the maturing stage soil acid phosphatase activity was enhanced with the applying soil phosphorus activator. The application of soil phosphorus activator increased alkali-hydrolyzable nitrogen and available phosphorus contents in soil, but did not increase available potassium content in soil. The optimal microbial inoculant application rate as applied as soil phosphorus activator was 7.5 kg·hm^(-2).展开更多
Bidens pilosa is recognized as one of the major invasive plants in China.Its invasion has been associated with significant losses in agriculture,forestry,husbandry,and biodiversity.Soil ecosystems play an important ro...Bidens pilosa is recognized as one of the major invasive plants in China.Its invasion has been associated with significant losses in agriculture,forestry,husbandry,and biodiversity.Soil ecosystems play an important role in alien plant invasion.Microorganisms within the soil act as intermediaries between plants and soil ecological functions,playing a role in regulating soil enzyme activities and nutrient dynamics.Understanding the interactions between invasive plants,soil microorganisms,and soil ecological processes is vital for managing and mitigating the impacts of invasive species on the environment.In this study,we conducted a systematic analysis focusing on B.pilosa and Setaria viridis,a common native companion plant in the invaded area.To simulate the invasion process of B.pilosa,we constructed homogeneous plots consisting of B.pilosa and S.viridis grown separately as monocultures,as well as in mixtures.The rhizosphere and bulk soils were collected from the alien plant B.pilosa and the native plant S.viridis.In order to focus on the soil ecological functional mechanisms that contribute to the successful invasion of B.pilosa,we analyzed the effects of B.pilosa on the composition of soil microbial communities and soil ecological functions.The results showed that the biomass of B.pilosa increased by 27.51% and that of S.viridis was significantly reduced by 66.56%.The organic matter contents in the bulk and rhizosphere soils of B.pilosa were approximately 1.30 times those in the native plant soils.The TN and NO_(3)^(-)contents in the rhizosphere soil of B.pilosa were 1.30 to 2.71 times those in the native plant soils.The activities of acid phosphatase,alkaline phosphatase,and urease in the rhizosphere soil of B.pilosa were 1.98-2.25 times higher than in the native plant soils.Using high-throughput sequencing of the16S rRNA gene,we found that B.pilosa altered the composition of the soil microbial community.Specifically,many genera in Actinobacteria and Proteobacteria were enriched in B.pilosa soils.Further correlation analyses verified that these genera had significantly positive relationships with soil nutrients and enzyme activities.Plant biomass,soil p H,and the contents of organic matter,TN,NO_(3)^(-),TP,AP,TK,and AK were the main factors affecting soil microbial communities.This study showed that the invasion of B.pilosa led to significant alterations in the composition of the soil microbial communities.These changes were closely linked to modifications in plant traits as well as soil physical and chemical properties.Some microbial species related to C,N and P cycling were enriched in the soil invaded by B.pilosa.These findings provide additional support for the hypothesis of soil-microbe feedback in the successful invasion of alien plants.They also offer insights into the ecological mechanism by which soil microbes contribute to the successful invasion of B.pilosa.Overall,our research contributes to a better understanding of the complex interactions between invasive plants,soil microbial communities,and ecosystem dynamics.展开更多
We carried out a pool culture experiment to determine the optimal water treatment depth in loam and clay soils during the late growth stage of super rice. Three controlled water depth treatments of 0–5, 0–10 and 0–...We carried out a pool culture experiment to determine the optimal water treatment depth in loam and clay soils during the late growth stage of super rice. Three controlled water depth treatments of 0–5, 0–10 and 0–15 cm below the soil surface were established using alternate wetting and drying irrigation, and the soil water potential(0 to –25 k Pa) was measured at 5, 10 and 15 cm. A2-cm water layer was used as the control. We measured soil enzyme activities, root antioxidant enzyme activities, chlorophyll fluorescence parameters, and rice yield. The results showed that the 0–5-cm water depth treatment significantly increased root antioxidant enzyme activities in loam soil compared with the control, whereas soil enzyme activities, chlorophyll fluorescence parameters and yield did not differ from those of the control. The 0–10-and 0–15-cm water depth treatments also increased root antioxidant enzyme activities, whereas soil enzyme activities, chlorophyll fluorescence parameters and yield decreased. In clay soil, the soil enzyme activities, root antioxidant enzyme activities, chlorophyll fluorescence parameters, and yield did not change with the 0–5-cm water treatment, whereas the 0–10-and 0–15-cm water treatments improved these parameters. Therefore, the appropriate depths for soil water during the late growth period of rice with a 0 to –25 k Pa water potential were 5 cm in loam and 15 cm in clay soil.展开更多
Through the pot experiment, the effects of different cropping patterns of soybean and maize seedlings on rhizosphere soil urease, catalase, polyphenol oxidase and invertase activities and microbial biomass carbon (MBC...Through the pot experiment, the effects of different cropping patterns of soybean and maize seedlings on rhizosphere soil urease, catalase, polyphenol oxidase and invertase activities and microbial biomass carbon (MBC) and nitrogen (MBN) were studied. Six treatments of soybean-soybean, soybean-maize, soybean-mixed, maize-soybean, maize-maize and maize-mixed were conducted in pots. Results showed that catalase activity and invertase activity of maize-maize were the highest and significantly different from those of the other treatments except maize-soybean; soil polyphenol oxidase activity of soybean-maize was the highest, and reached significant level among the other treatments, but there was no significant difference of urease activity among treatment soils; MBC of maize-maize soil and MBN of maize-mixed soil reached the highest and significant levels compared with other treatments; MBC and C/N ratio had positive and very significant correlations with soil catalase activity and invertase activity, respectively. Therefore, different cropping patterns could affect rhizosphere soil enzyme activities and soil MBC and MBN, which influenced soil carbon and nitrogen mineralization.展开更多
The effects of different amounts of carbon and nitrogen sources on the soil microbial biomass carbon,dissolved organic carbon and related enzyme activities were studied by the simulation experiment of rice straw retur...The effects of different amounts of carbon and nitrogen sources on the soil microbial biomass carbon,dissolved organic carbon and related enzyme activities were studied by the simulation experiment of rice straw returning to the field,and the mechanism of the decomposition of rice straw returning to the field was discussed.Completely randomized experiment of the two factors of the three levels was designed,and a total of nine treatments of indoor soil incubation tests were conducted.Full amount of rice straw was applied to the soil in this simulation experiment and different amounts of brown sugar and urea were added in the three levels of 0(no carbon source and nitrogen source),1(low levels of carbon and nitrogen sources)and 2(high levels of carbon and nitrogen sources),respectively.The results showed that the addition of different amounts of carbon and nitrogen sources to the rice straw could increase the soil carbon content.Compared with T0N0,the microbial biomass carbon of T2N2 was increased significantly by 170.48%;the dissolved organic carbon content of T1N2 was significantly increased by 58.14%and the free humic acid carbon contents of T0N2,T1N1 and T2N0 were significantly increased by 56.16%and 45.55%and 47.80%,respectively;however,there were no significant differences among those of treatments at later incubation periods.The addition of different carbon and nitrogen sources could promote the soil enzyme activities.During the incubation period,all of the soil enzyme activities of adding sugar and urea were higher than those of T0N0 treatment.Therefore,the addition of different amounts of carbon and nitrogen sources to rice straw returning could improve soil microbial biomass carbon content,dissolved organic carbon and soil enzyme activities.展开更多
The study of the heterogeneity of soil enzyme activities at different sampling locations in canopy gaps will help understand the influence mechanism of canopy gaps on soil ecological processes.In this paper,we analyze...The study of the heterogeneity of soil enzyme activities at different sampling locations in canopy gaps will help understand the influence mechanism of canopy gaps on soil ecological processes.In this paper,we analyzed the spatiotemporal variation of soil enzyme activities and soil physicochemical properties at different sampling locations(closed canopy,expanded edge,canopy edge,gap center)in different sampling time(December,February,April,June,August,and October)on the northern slope of the Tianshan Mountains,Northwest China.The results showed that soil catalase,cellulase,sucrase,and acid phosphatase activities were relatively high from June to October and low from December to April,and most of soil enzyme activities were higher at closed canopy than at gap center.Soil urease activity was high during December-February.The soil temperature reached the highest value during June-August and was relatively high at gap center in October,December,and February.Soil water content was significantly higher in December and April than in other months.Soil bulk density was higher at gap center than at closed canopy in December.Soil pH and soil electrical conductivity in most months were higher at closed canopy than at gap center.Soil organic carbon,soil total nitrogen,and soil total phosphorus were generally higher at gap center than at closed canopy.Furthermore,sampling time played a leading role in the dynamic change of soil enzyme activity.The key factors affecting soil enzyme activity were soil temperature and soil water content,which were governed by canopy gaps.These results provide important support for further understanding the influence mechanism of forest ecosystem management and conservation on the Tianshan Mountains.展开更多
Microorganisms regulate the responses of terrestrial ecosystems to anthropogenic nutrient inputs.The escalation of anthropogenic activities has resulted in a rise in the primary terrestrial constraining elements,namel...Microorganisms regulate the responses of terrestrial ecosystems to anthropogenic nutrient inputs.The escalation of anthropogenic activities has resulted in a rise in the primary terrestrial constraining elements,namely nitrogen(N)and phosphorus(P).Nevertheless,the specific mechanisms governing the influence of soil microbial community structure and ecological processes in ecologically vulnerable and delicate semi-arid loess agroecosystems remain inadequately understood.Therefore,we explored the effects of different N and P additions on soil microbial community structure and its associated ecological processes in the farmland of Chinese Loess Plateau based on a 36-a long-term experiment.Nine fertilization treatments with complete interactions of high,medium,and low N and P gradients were set up.Soil physical and chemical properties,along with the microbial community structure were measured in this study.Additionally,relevant ecological processes such as microbial biomass,respiration,N mineralization,and enzyme activity were quantified.To elucidate the relationships between these variables,we examined correlation-mediated processes using statistical techniques,including redundancy analysis(RDA)and structural equation modeling(SEM).The results showed that the addition of N alone had a detrimental effect on soil microbial biomass,mineralized N accumulation,andβ-1,4-glucosidase activity.Conversely,the addition of P exhibited an opposing effect,leading to positive influences on these soil parameters.The interactive addition of N and P significantly changed the microbial community structure,increasing microbial activity(microbial biomass and soil respiration),but decreasing the accumulation of mineralized N.Among them,N24P12 treatment showed the greatest increase in the soil nutrient content and respiration.N12P12 treatment increased the overall enzyme activity and total phospholipid fatty acid(PLFA)content by 70.93%.N and P nutrient contents of the soil dominate the microbial community structure and the corresponding changes in hydrolytic enzymes.Soil microbial biomass,respiration,and overall enzyme activity are driven by mineralized N.Our study provides a theoretical basis for exploring energy conversion processes of soil microbial community and environmental sustainability under long-term N and P additions in semi-arid loess areas.展开更多
Long-term straw return is an important carbon source for improving soil organic carbon(SOC) stocks in croplands, and straw removal through burning is also a common practice in open fields in South China. However, the ...Long-term straw return is an important carbon source for improving soil organic carbon(SOC) stocks in croplands, and straw removal through burning is also a common practice in open fields in South China. However, the specific effects of long-term rice straw management on SOC fractions, the related enzyme activities and their relationships, and whether these effects differ between crop growing seasons remain unknown. Three treatments with equal nitrogen, phosphorus, and potassium nutrient inputs, including straw/ash and chemical nutrients, were established to compare the effects of straw removal(CK), straw return(SR), and straw burned return(SBR). Compared to CK, long-term SR tended to improve the yield of early season rice(P=0.057), and significantly increased total organic carbon(TOC) and microbial biomass carbon(MBC) in double-cropped rice paddies. While SBR had no effect on TOC, it decreased light fraction organic carbon(LFOC) in early rice and easily oxidizable organic carbon(EOC) in late rice, significantly increased dissolved organic carbon(DOC), and significantly decreased soil p H. These results showed that MBC was the most sensitive indicator for assessing changes of SOC in the double-cropped rice system due to long-term straw return. In addition, the different effects on SOC fraction sizes between SR and SBR were attributed to the divergent trends in most of the soil enzyme activities in the early and late rice that mainly altered DOC, while DOC was positively affected by β-xylosidase in both early and late rice. We concluded that straw return was superior to straw burned return for improving SOC fractions, but the negative effects on soil enzyme activities in late rice require further research.展开更多
In semi-arid areas of China,gravel and sand mulch is a farming technique with a long history.In this study,a sample survey was conducted on long term gravel sand mulch observational fields in the Northwest Loess Plate...In semi-arid areas of China,gravel and sand mulch is a farming technique with a long history.In this study,a sample survey was conducted on long term gravel sand mulch observational fields in the Northwest Loess Plateau to determine the effects of long term mulch on soil microbial and soil enzyme activities.We found that after long term gravel-sand mulch,compared with bare ground,soil organic matter,alkali nitrogen,conductivity decreased,while pH and soil moisture increased.Urease,saccharase and catalase decreased with increased mulch thickness,while alkaline phosphatase was reversed.The results of Illumina MiSeq sequencing shows that after gravel-sand mulch,the bacterial and fungal community structure was different from bare land,and the diversity was reduced.Compared with bare land,the bacteria Proteobacteria and Acidobacteria abundance increased with increased thickness,and Actinobacteria was opposite.Also,at the fungal genus level,Fusarium abundance was significantly reduced,and Remersonia was significantly increased,compared with bare land.Redundancy analysis(RDA)revealed that soil environmental factors were important drivers of bacterial community changes.Overall,this study revealed some of the reasons for soil degradation after long term gravel-sand mulch.Therefore,it is recommended that the addition of exogenous soil nutrients after long term gravel-sand can help improve soil quality.展开更多
Soil management practices affect rhizosphere microorganisms and enzyme activities, which in turn influence soil ecosystem processes. The objective of this study was to explore the effects of different nitrogen applica...Soil management practices affect rhizosphere microorganisms and enzyme activities, which in turn influence soil ecosystem processes. The objective of this study was to explore the effects of different nitrogen application rates on wheat(Triticum aestivum L.) rhizosphere soil microorganisms and enzyme activities, and their temporal variations in relation to soil fertility under supplemental irrigation conditions in a fluvo-aquic region. For this, we established a split-plot experiment for two consecutive years(2014–2015 and 2015–2016) in the field with three levels of soil moisture: water deficit to no irrigation(W1), medium irrigation to(70±5)% of soil relative moisture after jointing stage(W2), and adequate irrigation to(80±5)% of soil relative moisture after jointing stage(W3);and three levels of nitrogen: 0 kg ha^–1(N1), 195 kg ha^–1(N2) and 270 kg ha^–1(N3). Results showed that irrigation and nitrogen application significantly increased rhizosphere microorganisms and enzyme activities. Soil microbiological properties showed different trends in response to N level;the highest values of bacteria, protease, catalase and phosphatase appeared in N2, while the highest levels of actinobacteria, fungi and urease were observed in N3. In addition, these items performed best under medium irrigation(W2) relative to W1 and W3;particularly the maximum microorganism(bacteria, actinobacteria and fungi) amounts appeared at W2, 5.37×10^7 and 6.35×10^7 CFUs g^–1 higher than those at W3 in 2014–2015 and 2015–2016, respectively;and these changes were similar in both growing seasons. Microbe-related parameters fluctuated over time but their seasonality did not hamper the irrigation and fertilization-induced effects. Further, the highest grain yields of 13 309.2 and 12 885.7 kg ha^–1 were both obtained at W2 N2 in 2014–2015 and 2015–2016, respectively. The selected properties, soil microorganisms and enzymes, were significantly correlated with wheat yield and proved to be valuable indicators of soil quality. These results clearly demonstrated that the combined treatment(W2 N2) significantly improved soil microbiological properties, soil fertility and wheat yield on the Huanghuai Plain, China.展开更多
In terrestrial ecosystems,deep soils(below 30 cm)are major organic carbon(C)pools.The labile carbon input could alter soil organic carbon(SOC)mineralization,resulting in priming effect(PE),which could be modified by n...In terrestrial ecosystems,deep soils(below 30 cm)are major organic carbon(C)pools.The labile carbon input could alter soil organic carbon(SOC)mineralization,resulting in priming effect(PE),which could be modified by nitrogen(N)availability,however,the underlying mechanism is unclear for deep soils,which complicates the prediction of deep soil C cycling in response to N deposition.A series of N applications with ^(13)C labeled glucose was set to investigate the effect of labile C and N on deep SOC mineralization.Microbial biomass,functional community,metabolic efficiency and enzyme activities were examined for their effects on SOC mineralization and PE.During incubation,glucose addition promoted SOC mineralization,resulting in positive PE.The magnitude of PE decreased significantly with increasing N.The N-regulated PE was not dependent on extracellular enzyme activities but was positively correlated with carbon use efficiency and negatively with metabolic quotient.Higher N levels resulted in higher microbial biomass and SOC-derived microbial biomass than lower N levels.These results suggest that the decline in the PE under high N availability was mainly controlled by higher microbial metabolic efficiency which allocated more C for growth.Structural equation modelling also revealed that microbial metabolic efficiency rather than enzyme activities was the main factor regulating the PE.The negative effect of additional N suggests that future N deposition could promote soil C sequestration.展开更多
It is of great significance to study the effects of desert plants on soil enzyme activities and soil organic carbon(SOC)for maintaining the stability of the desert ecosystem.In this study,we studied the responses of s...It is of great significance to study the effects of desert plants on soil enzyme activities and soil organic carbon(SOC)for maintaining the stability of the desert ecosystem.In this study,we studied the responses of soil enzyme activities and SOC fractions(particulate organic carbon(POC)and mineral-associated organic carbon(MAOC))to five typical desert plant communities(Convolvulus tragacanthoides,Ephedra rhytidosperma,Stipa breviflora,Stipa tianschanica var.gobica,and Salsola laricifolia communities)in the proluvial fan in the eastern foothills of the Helan Mountain in Ningxia Hui Autonomous Region,China.We recorded the plant community information mainly including the plant coverage and herb and shrub species,and obtained the aboveground biomass and plant species diversity through sample surveys in late July 2023.Soil samples were also collected at depths of 0–10 cm(topsoil)and 10–20 cm(subsoil)to determine the soil physicochemical properties and enzyme activities.The results showed that the plant coverage and aboveground biomass of S.laricifolia community were significantly higher than those of C.tragacanthoides,S.breviflora,and S.tianschanica var.gobica communities(P<0.05).Soil enzyme activities varied among different plant communities.In the topsoil,the enzyme activities of alkaline phosphatase(ALP)andβ-1,4-glucosidas(βG)were significantly higher in E.rhytidosperma and S.tianschanica var.gobica communities than in other plant communities(P<0.05).The topsoil had higher POC and MAOC contents than the subsoil.Specifically,the content of POC in the topsoil was 18.17%–42.73%higher than that in the subsoil.The structural equation model(SEM)indicated that plant species diversity,soil pH,and soil water content(SWC)were the main factors influencing POC and MAOC.The soil pH inhibited the formation of POC and promoted the formation of MAOC.Conversely,SWC stimulated POC production and hindered MAOC formation.Our study aimed to gain insight into the effects of desert plant communities on soil enzyme activities and SOC fractions,as well as the drivers of SOC fractions in the proluvial fan in the eastern foothills of the Helan Mountain and other desert ecosystems.展开更多
Legume cultivars affect N uptake,component crop growth,and soil physical and chemical characteristics in maize-legume intercropping systems.However,how belowground interactions mediate root growth,N fixation,and nodul...Legume cultivars affect N uptake,component crop growth,and soil physical and chemical characteristics in maize-legume intercropping systems.However,how belowground interactions mediate root growth,N fixation,and nodulation of different legumes to affect N uptake is still unclear.Hence,a two-year experiment was conducted with five planting patterns,i.e.,maize-soybean strip intercropping(IMS),maize-peanut strip intercropping(IMP),and corresponding monocultures(monoculture maize(MM),monoculture soybean(MS),and monoculture peanut(MP)),and two N application rates,i.e.,no N fertilizer(N-)and conventional N fertilizer(N+),to examine relationships between N uptake and root distribution of crops,legume nodulation and soil N availability.Results showed that the averaged N uptake per unit area of intercrops was significantly lower than the corresponding monocultures.Compared with the monoculture system,the N uptake of the intercropping systems increased by 31.7-45.4%in IMS and by 7.4-12.2%in IMP,respectively.The N uptake per plant of intercropped maize and soybean significantly increased by 61.6 and 31.8%,and that of intercropped peanuts significantly decreased by 46.6%compared with the corresponding monocultures.Maize and soybean showed asymmetrical distribution of roots in strip intercropping systems.The root length density(RLD)and root surface area density(RSAD)of intercropped maize and soybean were significantly greater than that of the corresponding monocultures.The roots of intercropped peanuts were confined,which resulted in decreased RLD and RSAD compared with the monoculture.The nodule number and nodule fresh weight of soybean were significantly greater in IMS than in MS,and those of peanut were significantly lower in IMP than in MP.The soil protease,urease,and nitrate reductase activities of maize and soybean were significantly greater in IMS and IMP than in the corresponding monoculture,while the enzyme activities of peanut were significantly lower in IMP than in MP.The soil available N of maize and soybean was significantly greater increased in IMS and IMP than in the corresponding monocultures,while that of IMP was significantly lower than in MP.In summary,the IMS system was more beneficial to N uptake than the IMP system.The intercropping of maize and legumes can promote the N uptake of maize,thus reducing the need for N application and improving agricultural sustainability.展开更多
Background:There is substantial evidence that Eucalyptus for nitrogen(N)absorption and increasing the growth benefit from the introduction of N-fixing species,but the underlying mechanisms for microbially mediated soi...Background:There is substantial evidence that Eucalyptus for nitrogen(N)absorption and increasing the growth benefit from the introduction of N-fixing species,but the underlying mechanisms for microbially mediated soil N cycling remains unclear.Methods:We investigated the changes of soil pH,soil water content(SWC),soil organic carbon(SOC),total N(TN),inorganic N(NH_(4)^(+)-N and NO_(3)^(-)-N),microbial biomass and three N-degrading enzyme activities as well as the biomass and N productivity of Eucalyptus between a pure Eucalyptus urophylla×grandis plantation(PP)and a mixed Dalbergia odorifera and Eucalyptus plantation(MP)in Guangxi Zhuang Autonomous Region,China.Results:Compared with the PP site,soil pH,SWC,SOC and TN in both seasons were significantly higher at the MP site,which in turn enhanced microbial biomass and the activities of soil N-degrading enzymes.The stimulated microbial activity at the MP site likely accelerate soil N mineralization,providing more available N(NH_(4)^(+)-N in both seasons and NO_(3)^(-)-N in the wet-hot season)for Eucalyptus absorption.Overall,the N productivity of Eucalyptus at the MP site was increased by 19.7% and 21.9%,promoting the biomass increases of 15.1% and 19.2% in the drycold season and wet-hot season,respectively.Conclusion:Our results reveal the importance of microbially mediated soil N cycling in the N absorption on Eucalyptus.Introduction of D.odorifera enhances Eucalyptus biomass and N productivity,improve soil N availability and increased soil C and N concentration,which hence can be considered to be an effective sustainable management option of Eucalyptus plantations.展开更多
Soil microbial biomass carbon (MBC), β-glucosidase, acid phosphatase and fluorescein diacetate (FDA) activities and bacterial community structure were assessed in a long-term (26 years) experiment, at physiological s...Soil microbial biomass carbon (MBC), β-glucosidase, acid phosphatase and fluorescein diacetate (FDA) activities and bacterial community structure were assessed in a long-term (26 years) experiment, at physiological stages of sorghum growth, comparing different management methods for organic (manure, straw residues) and inorganic (urea) amendments at the INERA field station in Saria (Burkina Faso). Annual application of manure led to the highest soil microbial biomass and enzyme activities. Investigations indicated that only microbial biomass and β-glucosidase activities were affected during the cropping season. Phosphatase and FDA enzyme activities did not depend on the crop development stages. The application of N fertilizer modified phosphatase and FDA enzyme activities, the activities being higher in soils amended with N fertilizer. The bacterial community structure was analyzed by PCR-denaturing gradient gel electrophoresis (PCR-DGGE) targeting the eubacterial 16S rRNA gene. Cluster analysis of PCR-DGGE patterns showed two major clusters, the first containing the mineral fertilization and straw treatments and the second, the straw + urea, manure and manure + urea treatments. Sorghum grain yields were the highest for manure treatments. In this long-term experiment, applying straw did not produce a better grain yield than that obtained in the un-amended plot.展开更多
Lead(Pb)pollution is one of the most widespread and harmful environmental problems worldwide.Determination of changes in soil properties and microbial functional diversity due to land use is needed to establish a basi...Lead(Pb)pollution is one of the most widespread and harmful environmental problems worldwide.Determination of changes in soil properties and microbial functional diversity due to land use is needed to establish a basis for remediation of soil pollution.This study aimed to investigate soils contaminated by Pb from different sources and to analyze the functional diversity and metabolism of soil microbial communities using Biolog technology.Pb pollution(>300 mg kg-1)significantly influenced the diversity and metabolic functions of soil microbial communities.Specifically,Pb contamination significantly reduced soil microbial biomass carbon(C)and nitrogen(N)levels and catalase activity while increasing invertase activity.Furthermore,Biolog EcoPlate assays revealed that Pb pollution reduced the general activities of soil microorganisms,suppressing their ability to utilize C sources.In Pb-contaminated areas lacking vegetation cover,Shannon,Simpson,and McIntosh diversity indices of soil microorganisms were significantly reduced.The microbial diversity and biomass C and N levels were affected by land use and soil properties,respectively,whereas soil enzyme activity was primarily affected by the interaction between land use and soil properties.Our results provide a reference and a theoretical basis for developing soil quality evaluation and remediation strategies.展开更多
基金Supported by Key R&D Program of the Ministry of Science and Technology of China(2017YFC0505102-4)。
文摘[Objectives]In response to the issue of soil improvement in Yuanmou County,the effects of combined application of biochar-based organic fertilizer and reduced nitrogen fertilizer on soil nutrients,soil enzyme activity,and yield of purple cabbage(Brassica oleracea var.capita rubra)were investigated in the field base of Institute of Thermal Zone Ecological Agriculture,Yunnan Academy of Agricultural Sciences in Yuanmou County.[Methods]A total of 13 treatments were set up by applying biochar-based organic fertilizer at three levels of 15,30 and 45 t/hm^(2)(T_(1),T_(2),T_(3)),combined with top application of nitrogen fertilizer(urea)at four levels:375(N_1),300(N_(2)),225(N_(3))and 0 kg/hm^(2),with non-fertilizing treatment as control check(CK),in order to explore the optimal ratio for the combined application of biochar-based organic fertilizer with nitrogen fertilizer.[Results]The application of biochar-based organic fertilizer could significantly improve soil nutrients,enzyme activity,and purple cabbage yield.The improvement effect of combined application with nitrogen fertilizer was higher than that of single application of biochar-based organic fertilizer,and the improvement effect was enhanced with the application amount of biochar-based organic fertilizer increasing.The contents of organic matter and total nitrogen were the highest in treatment T_(3)N_(3),of which the values increased by 81.39%and 56.09%compared with the CK,respectively.The contents of soil hydrolyzable nitrogen,available phosphorus,and available potassium were all the highest under treatment T_(3)N_(2),with increases of 92.76%,171.01%and 235.50%,respectively.There was a significant positive correlation between the activity of soil catalase,urease,and sucrase and organic matter,total nitrogen,and available nutrients.The overall soil enzyme activity was relatively higher in treatment T_(3)N_(2).The yield of purple cabbage treated with biochar-based organic fertilizer combined with nitrogen fertilizer could reach 85750 kg/hm^(2),which was 94.78%higher than that treated with biochar-based organic fertilizer alone.Based on comprehensive analysis,the optimal combination ratio was 45 t/hm^(2)of biochar-based organic fertilizer and 300 kg/hm^(2)of urea(T_(3)N_(2)).[Conclusions]This study provides data support for the promotion of biochar-based organic fertilizers and reduced fertilizer in agricultural soil in the Dam area of Yuanmou County.
基金Supported by National Natural Science Foundation of China (31870484)。
文摘[Objectives]This study was conducted to evaluate the effects of carbon nanomaterials on soil ecosystem and explore the ecological risks of environmental exposure of carbon nanomaterials. [Methods] The effects of carbon nanomaterials on soil enzyme activity was studied by adding graphene, graphene oxide and carbon nanotubes to turfgrass soil. [Results] Compared with the control(CK), the activity of soil protease, sucrase, alkaline phosphatase and catalase was not significantly affected by carbon nanomaterials. Under the treatment of carbon nanotubes, urease activity was significantly lower than that of graphene and graphene oxide, and dehydrogenase activity was significantly lower than that of the CK, graphene and graphene oxide. [Conclusions] This study provides a theoretical basis for the safe application of carbon nanomaterials.
基金Supported by Special Fund of Lishui City for Public Interest(2021GYX11)Special Fund of Zhejiang Provincial Department of Finance for Basic Research and Development of Bamboo Charcoal-based Soil Conditioner(20180021)Key Research and Development Project of Zhejiang Province(2018C02031)。
文摘[Objectives]This study was conducted to reveal the effects of bamboo charcoal-based biochar(or bamboo charcoal for short)on soil enzyme activity and microbial community structure.[Methods]The field experiment was carried out at the Modern Agriculture Demonstration Base of Gaoping Village,Gaoping Town,Suichang County,Zhejiang Province.Bamboo charcoal was applied at four different levels:T_(0)(no bamboo charcoal),T_(1)(1125 kg/hm^(2)bamboo charcoal),T_(2)(2250 kg/hm^(2)bamboo charcoal)and T_(3)(3375 kg/hm^(2)bamboo charcoal).Soil physicochemical properties and enzyme activities in different treatments were measured.[Results]The soil fungal,bacterial and actinomycete populations increased significantly in the soils surrounding capsicum roots.The bacterial population,fungal population and fungus/bacterium ratio peaked in Treatment T_(2),up to 7.32×10^(6)cfu/g,2.65×10^(4)cfu/g and 0.36×10^(-2),respectively.The effect of bamboo charcoal in promotingβ-glucoside,catalase,acid phosphatase and sucrase activities was T_(2)>T_(3)>T_(1)>T_(0).With bamboo charcoal increasing,the bacterium population,fungus population,fungus/bacterium ratio,β-glucoside,catalase,acid phosphatase and sucrase activities all increased at first and then decreased.T_(2)treatment showed the best effects in improving soil physicochemical properties and microbial community structure.[Conclusions]Bamboo charcoal significantly improves soil enzyme activity and increases soil microbial population,and thus has important positive effects on the soil ecosystem.
基金Natural Science Foundation of Guangxi(GKZ 0832273)Laboratory of Comprehensive Prevention and Control of Rocky Desertification in Karst Areas in Northwest Guangxi(XZF[2016]91)+1 种基金High-level Talent Research Startup Fund of Hechi University(XJ2018GKQ016)Undergraduate Innovation and Enterpreneurship Training Program of Guangxi(201810605086).
文摘[Objectives]This study was conducted to investigate the effects of Vitis heyneana cultivation on rocky hillsides on the variation of soil fertility,so as to provide theoretical support for economic development and the control of rocky desertification in the Dashi mountainous area.[Methods]Taking V.heyneana planting base in Luocheng County,Hechi City,Guangxi Province as the research object,the methods of field investigation,regular sampling and experimental analysis were used to analyze seasonal variations of soil urease,sucrase and soil alkaline phosphatase activity of 15 different sample plots surveyed,and their correlation with soil physical and chemical properties was analyzed.[Results]①In general,sucrase,urease and alkaline phosphatase were lower in summer and autumn,and higher in spring and winter,and the performance of the activity of the three enzymes was inconsistent.Among them,the activity of sucrase was in order of spring>autumn>summer>winter,and the activity of urease and alkaline phosphatase showed an order of winter>spring>summer>autumn.②The seasonal variations of soil fertility in different sample plots were affected by various factors such as human disturbance,climate change,vegetation coverage,topography and landforms,cultivation and management measures,and although the change laws in different sample plots were different,the seasonal differences in soil fertility in the same place were extremely significant.③If the influence of artificial fertilization factors is excluded,the planting of V.heyneana on rocky hillsides will cause a significant decrease in soil enzyme activity,that is,a significant decrease in soil fertility.[Conclusions]Related issues such as the effects of planting V.heyneana on the variation of soil fertility in rocky hillsides should arouse necessary attention of management departments and producers.
文摘The experiment was conducted to study the impact of application of microbial inoculants, compared with no microbial fertilizer, on enzyme activity, microbial biomass and available nutrient contents in paddy soil in Heilongjiang Province. The application of soil phosphorus activator was able to increase the quantity of bacteria and fungi in soil, but its effect on actinomycetes in soil was not significant. The application of microbial inoculants increased the urease and sucrase activities in soil over the growing season, but only at the maturing stage soil acid phosphatase activity was enhanced with the applying soil phosphorus activator. The application of soil phosphorus activator increased alkali-hydrolyzable nitrogen and available phosphorus contents in soil, but did not increase available potassium content in soil. The optimal microbial inoculant application rate as applied as soil phosphorus activator was 7.5 kg·hm^(-2).
基金funded by the National Key R&D Program of China(2022YFC2601100,2021YFD1400100 and 2021YFC2600400)the National Natural Science Foundation of China(42207162)。
文摘Bidens pilosa is recognized as one of the major invasive plants in China.Its invasion has been associated with significant losses in agriculture,forestry,husbandry,and biodiversity.Soil ecosystems play an important role in alien plant invasion.Microorganisms within the soil act as intermediaries between plants and soil ecological functions,playing a role in regulating soil enzyme activities and nutrient dynamics.Understanding the interactions between invasive plants,soil microorganisms,and soil ecological processes is vital for managing and mitigating the impacts of invasive species on the environment.In this study,we conducted a systematic analysis focusing on B.pilosa and Setaria viridis,a common native companion plant in the invaded area.To simulate the invasion process of B.pilosa,we constructed homogeneous plots consisting of B.pilosa and S.viridis grown separately as monocultures,as well as in mixtures.The rhizosphere and bulk soils were collected from the alien plant B.pilosa and the native plant S.viridis.In order to focus on the soil ecological functional mechanisms that contribute to the successful invasion of B.pilosa,we analyzed the effects of B.pilosa on the composition of soil microbial communities and soil ecological functions.The results showed that the biomass of B.pilosa increased by 27.51% and that of S.viridis was significantly reduced by 66.56%.The organic matter contents in the bulk and rhizosphere soils of B.pilosa were approximately 1.30 times those in the native plant soils.The TN and NO_(3)^(-)contents in the rhizosphere soil of B.pilosa were 1.30 to 2.71 times those in the native plant soils.The activities of acid phosphatase,alkaline phosphatase,and urease in the rhizosphere soil of B.pilosa were 1.98-2.25 times higher than in the native plant soils.Using high-throughput sequencing of the16S rRNA gene,we found that B.pilosa altered the composition of the soil microbial community.Specifically,many genera in Actinobacteria and Proteobacteria were enriched in B.pilosa soils.Further correlation analyses verified that these genera had significantly positive relationships with soil nutrients and enzyme activities.Plant biomass,soil p H,and the contents of organic matter,TN,NO_(3)^(-),TP,AP,TK,and AK were the main factors affecting soil microbial communities.This study showed that the invasion of B.pilosa led to significant alterations in the composition of the soil microbial communities.These changes were closely linked to modifications in plant traits as well as soil physical and chemical properties.Some microbial species related to C,N and P cycling were enriched in the soil invaded by B.pilosa.These findings provide additional support for the hypothesis of soil-microbe feedback in the successful invasion of alien plants.They also offer insights into the ecological mechanism by which soil microbes contribute to the successful invasion of B.pilosa.Overall,our research contributes to a better understanding of the complex interactions between invasive plants,soil microbial communities,and ecosystem dynamics.
基金supported by the National Natural Science Foundation of China(31271651)the Major Science and Technology Project of Henan Province,China(141100110600)+1 种基金the Special Fund for Agro-scientific Research in the Public Interest of China(201303102)the Innovation Scientists and Technicians Troop Construction Projects of Henan Province,China(94200510003)
文摘We carried out a pool culture experiment to determine the optimal water treatment depth in loam and clay soils during the late growth stage of super rice. Three controlled water depth treatments of 0–5, 0–10 and 0–15 cm below the soil surface were established using alternate wetting and drying irrigation, and the soil water potential(0 to –25 k Pa) was measured at 5, 10 and 15 cm. A2-cm water layer was used as the control. We measured soil enzyme activities, root antioxidant enzyme activities, chlorophyll fluorescence parameters, and rice yield. The results showed that the 0–5-cm water depth treatment significantly increased root antioxidant enzyme activities in loam soil compared with the control, whereas soil enzyme activities, chlorophyll fluorescence parameters and yield did not differ from those of the control. The 0–10-and 0–15-cm water depth treatments also increased root antioxidant enzyme activities, whereas soil enzyme activities, chlorophyll fluorescence parameters and yield decreased. In clay soil, the soil enzyme activities, root antioxidant enzyme activities, chlorophyll fluorescence parameters, and yield did not change with the 0–5-cm water treatment, whereas the 0–10-and 0–15-cm water treatments improved these parameters. Therefore, the appropriate depths for soil water during the late growth period of rice with a 0 to –25 k Pa water potential were 5 cm in loam and 15 cm in clay soil.
基金Supported by the Scientific Research Foundation for Doctor of Northeast Agricultural UniversityInnovative Team Fund of Northeast Agricultural University
文摘Through the pot experiment, the effects of different cropping patterns of soybean and maize seedlings on rhizosphere soil urease, catalase, polyphenol oxidase and invertase activities and microbial biomass carbon (MBC) and nitrogen (MBN) were studied. Six treatments of soybean-soybean, soybean-maize, soybean-mixed, maize-soybean, maize-maize and maize-mixed were conducted in pots. Results showed that catalase activity and invertase activity of maize-maize were the highest and significantly different from those of the other treatments except maize-soybean; soil polyphenol oxidase activity of soybean-maize was the highest, and reached significant level among the other treatments, but there was no significant difference of urease activity among treatment soils; MBC of maize-maize soil and MBN of maize-mixed soil reached the highest and significant levels compared with other treatments; MBC and C/N ratio had positive and very significant correlations with soil catalase activity and invertase activity, respectively. Therefore, different cropping patterns could affect rhizosphere soil enzyme activities and soil MBC and MBN, which influenced soil carbon and nitrogen mineralization.
基金Supported by the National Key Research and Development Plan Project(2016YFD0300909-04)。
文摘The effects of different amounts of carbon and nitrogen sources on the soil microbial biomass carbon,dissolved organic carbon and related enzyme activities were studied by the simulation experiment of rice straw returning to the field,and the mechanism of the decomposition of rice straw returning to the field was discussed.Completely randomized experiment of the two factors of the three levels was designed,and a total of nine treatments of indoor soil incubation tests were conducted.Full amount of rice straw was applied to the soil in this simulation experiment and different amounts of brown sugar and urea were added in the three levels of 0(no carbon source and nitrogen source),1(low levels of carbon and nitrogen sources)and 2(high levels of carbon and nitrogen sources),respectively.The results showed that the addition of different amounts of carbon and nitrogen sources to the rice straw could increase the soil carbon content.Compared with T0N0,the microbial biomass carbon of T2N2 was increased significantly by 170.48%;the dissolved organic carbon content of T1N2 was significantly increased by 58.14%and the free humic acid carbon contents of T0N2,T1N1 and T2N0 were significantly increased by 56.16%and 45.55%and 47.80%,respectively;however,there were no significant differences among those of treatments at later incubation periods.The addition of different carbon and nitrogen sources could promote the soil enzyme activities.During the incubation period,all of the soil enzyme activities of adding sugar and urea were higher than those of T0N0 treatment.Therefore,the addition of different amounts of carbon and nitrogen sources to rice straw returning could improve soil microbial biomass carbon content,dissolved organic carbon and soil enzyme activities.
基金supported by the National Natural Science Foundation of China (31760142)
文摘The study of the heterogeneity of soil enzyme activities at different sampling locations in canopy gaps will help understand the influence mechanism of canopy gaps on soil ecological processes.In this paper,we analyzed the spatiotemporal variation of soil enzyme activities and soil physicochemical properties at different sampling locations(closed canopy,expanded edge,canopy edge,gap center)in different sampling time(December,February,April,June,August,and October)on the northern slope of the Tianshan Mountains,Northwest China.The results showed that soil catalase,cellulase,sucrase,and acid phosphatase activities were relatively high from June to October and low from December to April,and most of soil enzyme activities were higher at closed canopy than at gap center.Soil urease activity was high during December-February.The soil temperature reached the highest value during June-August and was relatively high at gap center in October,December,and February.Soil water content was significantly higher in December and April than in other months.Soil bulk density was higher at gap center than at closed canopy in December.Soil pH and soil electrical conductivity in most months were higher at closed canopy than at gap center.Soil organic carbon,soil total nitrogen,and soil total phosphorus were generally higher at gap center than at closed canopy.Furthermore,sampling time played a leading role in the dynamic change of soil enzyme activity.The key factors affecting soil enzyme activity were soil temperature and soil water content,which were governed by canopy gaps.These results provide important support for further understanding the influence mechanism of forest ecosystem management and conservation on the Tianshan Mountains.
基金funded by the Project of Science and Technology Department of Shaanxi Province,China(2022NY-074)the National Natural Science Foundation of China(41501255)+1 种基金the Xi'an Science and Technology Project(21NYYF0033)the Fundamental Research Funds for the Central Universities(SYJS202224,GK202206032).
文摘Microorganisms regulate the responses of terrestrial ecosystems to anthropogenic nutrient inputs.The escalation of anthropogenic activities has resulted in a rise in the primary terrestrial constraining elements,namely nitrogen(N)and phosphorus(P).Nevertheless,the specific mechanisms governing the influence of soil microbial community structure and ecological processes in ecologically vulnerable and delicate semi-arid loess agroecosystems remain inadequately understood.Therefore,we explored the effects of different N and P additions on soil microbial community structure and its associated ecological processes in the farmland of Chinese Loess Plateau based on a 36-a long-term experiment.Nine fertilization treatments with complete interactions of high,medium,and low N and P gradients were set up.Soil physical and chemical properties,along with the microbial community structure were measured in this study.Additionally,relevant ecological processes such as microbial biomass,respiration,N mineralization,and enzyme activity were quantified.To elucidate the relationships between these variables,we examined correlation-mediated processes using statistical techniques,including redundancy analysis(RDA)and structural equation modeling(SEM).The results showed that the addition of N alone had a detrimental effect on soil microbial biomass,mineralized N accumulation,andβ-1,4-glucosidase activity.Conversely,the addition of P exhibited an opposing effect,leading to positive influences on these soil parameters.The interactive addition of N and P significantly changed the microbial community structure,increasing microbial activity(microbial biomass and soil respiration),but decreasing the accumulation of mineralized N.Among them,N24P12 treatment showed the greatest increase in the soil nutrient content and respiration.N12P12 treatment increased the overall enzyme activity and total phospholipid fatty acid(PLFA)content by 70.93%.N and P nutrient contents of the soil dominate the microbial community structure and the corresponding changes in hydrolytic enzymes.Soil microbial biomass,respiration,and overall enzyme activity are driven by mineralized N.Our study provides a theoretical basis for exploring energy conversion processes of soil microbial community and environmental sustainability under long-term N and P additions in semi-arid loess areas.
基金supported by the National Key Research and Development Program of China (2017YFD0301601)the China Postdoctoral Science Foundation (2016M600512)+1 种基金the Open Project Program of State Key Laboratory of Rice Biology, Ministry of Science and Technology, China (20190401)the Jiangxi Province Postdoctoral Research Project Preferential Grant, China (2017KY16)。
文摘Long-term straw return is an important carbon source for improving soil organic carbon(SOC) stocks in croplands, and straw removal through burning is also a common practice in open fields in South China. However, the specific effects of long-term rice straw management on SOC fractions, the related enzyme activities and their relationships, and whether these effects differ between crop growing seasons remain unknown. Three treatments with equal nitrogen, phosphorus, and potassium nutrient inputs, including straw/ash and chemical nutrients, were established to compare the effects of straw removal(CK), straw return(SR), and straw burned return(SBR). Compared to CK, long-term SR tended to improve the yield of early season rice(P=0.057), and significantly increased total organic carbon(TOC) and microbial biomass carbon(MBC) in double-cropped rice paddies. While SBR had no effect on TOC, it decreased light fraction organic carbon(LFOC) in early rice and easily oxidizable organic carbon(EOC) in late rice, significantly increased dissolved organic carbon(DOC), and significantly decreased soil p H. These results showed that MBC was the most sensitive indicator for assessing changes of SOC in the double-cropped rice system due to long-term straw return. In addition, the different effects on SOC fraction sizes between SR and SBR were attributed to the divergent trends in most of the soil enzyme activities in the early and late rice that mainly altered DOC, while DOC was positively affected by β-xylosidase in both early and late rice. We concluded that straw return was superior to straw burned return for improving SOC fractions, but the negative effects on soil enzyme activities in late rice require further research.
基金This study was funded by the National Key R&D Program(Grant No.2016YFC0501403-3).
文摘In semi-arid areas of China,gravel and sand mulch is a farming technique with a long history.In this study,a sample survey was conducted on long term gravel sand mulch observational fields in the Northwest Loess Plateau to determine the effects of long term mulch on soil microbial and soil enzyme activities.We found that after long term gravel-sand mulch,compared with bare ground,soil organic matter,alkali nitrogen,conductivity decreased,while pH and soil moisture increased.Urease,saccharase and catalase decreased with increased mulch thickness,while alkaline phosphatase was reversed.The results of Illumina MiSeq sequencing shows that after gravel-sand mulch,the bacterial and fungal community structure was different from bare land,and the diversity was reduced.Compared with bare land,the bacteria Proteobacteria and Acidobacteria abundance increased with increased thickness,and Actinobacteria was opposite.Also,at the fungal genus level,Fusarium abundance was significantly reduced,and Remersonia was significantly increased,compared with bare land.Redundancy analysis(RDA)revealed that soil environmental factors were important drivers of bacterial community changes.Overall,this study revealed some of the reasons for soil degradation after long term gravel-sand mulch.Therefore,it is recommended that the addition of exogenous soil nutrients after long term gravel-sand can help improve soil quality.
基金supported by the National Technology R&D Program of China (2013BAD07B07, 2015BAD26B01 and 2018YFD0300701)
文摘Soil management practices affect rhizosphere microorganisms and enzyme activities, which in turn influence soil ecosystem processes. The objective of this study was to explore the effects of different nitrogen application rates on wheat(Triticum aestivum L.) rhizosphere soil microorganisms and enzyme activities, and their temporal variations in relation to soil fertility under supplemental irrigation conditions in a fluvo-aquic region. For this, we established a split-plot experiment for two consecutive years(2014–2015 and 2015–2016) in the field with three levels of soil moisture: water deficit to no irrigation(W1), medium irrigation to(70±5)% of soil relative moisture after jointing stage(W2), and adequate irrigation to(80±5)% of soil relative moisture after jointing stage(W3);and three levels of nitrogen: 0 kg ha^–1(N1), 195 kg ha^–1(N2) and 270 kg ha^–1(N3). Results showed that irrigation and nitrogen application significantly increased rhizosphere microorganisms and enzyme activities. Soil microbiological properties showed different trends in response to N level;the highest values of bacteria, protease, catalase and phosphatase appeared in N2, while the highest levels of actinobacteria, fungi and urease were observed in N3. In addition, these items performed best under medium irrigation(W2) relative to W1 and W3;particularly the maximum microorganism(bacteria, actinobacteria and fungi) amounts appeared at W2, 5.37×10^7 and 6.35×10^7 CFUs g^–1 higher than those at W3 in 2014–2015 and 2015–2016, respectively;and these changes were similar in both growing seasons. Microbe-related parameters fluctuated over time but their seasonality did not hamper the irrigation and fertilization-induced effects. Further, the highest grain yields of 13 309.2 and 12 885.7 kg ha^–1 were both obtained at W2 N2 in 2014–2015 and 2015–2016, respectively. The selected properties, soil microorganisms and enzymes, were significantly correlated with wheat yield and proved to be valuable indicators of soil quality. These results clearly demonstrated that the combined treatment(W2 N2) significantly improved soil microbiological properties, soil fertility and wheat yield on the Huanghuai Plain, China.
基金supported by the Natural Science Foundation of China(Grant numbers 31870465,31600377,31700462).
文摘In terrestrial ecosystems,deep soils(below 30 cm)are major organic carbon(C)pools.The labile carbon input could alter soil organic carbon(SOC)mineralization,resulting in priming effect(PE),which could be modified by nitrogen(N)availability,however,the underlying mechanism is unclear for deep soils,which complicates the prediction of deep soil C cycling in response to N deposition.A series of N applications with ^(13)C labeled glucose was set to investigate the effect of labile C and N on deep SOC mineralization.Microbial biomass,functional community,metabolic efficiency and enzyme activities were examined for their effects on SOC mineralization and PE.During incubation,glucose addition promoted SOC mineralization,resulting in positive PE.The magnitude of PE decreased significantly with increasing N.The N-regulated PE was not dependent on extracellular enzyme activities but was positively correlated with carbon use efficiency and negatively with metabolic quotient.Higher N levels resulted in higher microbial biomass and SOC-derived microbial biomass than lower N levels.These results suggest that the decline in the PE under high N availability was mainly controlled by higher microbial metabolic efficiency which allocated more C for growth.Structural equation modelling also revealed that microbial metabolic efficiency rather than enzyme activities was the main factor regulating the PE.The negative effect of additional N suggests that future N deposition could promote soil C sequestration.
基金the Key Project of the Natural Science Foundation of Ningxia Hui Autonomous Region,China(2022AAC02020)the Major Strategic Research Project of the Chinese Academy of Engineering and Local Cooperation(2021NXZD8)the Key Research and Development Plan Project of Ningxia Hui Autonomous Region,China(2022004129003).We are grateful to the editors and anonymous reviewers for their insightful comments and suggestions in improving this manuscript.
文摘It is of great significance to study the effects of desert plants on soil enzyme activities and soil organic carbon(SOC)for maintaining the stability of the desert ecosystem.In this study,we studied the responses of soil enzyme activities and SOC fractions(particulate organic carbon(POC)and mineral-associated organic carbon(MAOC))to five typical desert plant communities(Convolvulus tragacanthoides,Ephedra rhytidosperma,Stipa breviflora,Stipa tianschanica var.gobica,and Salsola laricifolia communities)in the proluvial fan in the eastern foothills of the Helan Mountain in Ningxia Hui Autonomous Region,China.We recorded the plant community information mainly including the plant coverage and herb and shrub species,and obtained the aboveground biomass and plant species diversity through sample surveys in late July 2023.Soil samples were also collected at depths of 0–10 cm(topsoil)and 10–20 cm(subsoil)to determine the soil physicochemical properties and enzyme activities.The results showed that the plant coverage and aboveground biomass of S.laricifolia community were significantly higher than those of C.tragacanthoides,S.breviflora,and S.tianschanica var.gobica communities(P<0.05).Soil enzyme activities varied among different plant communities.In the topsoil,the enzyme activities of alkaline phosphatase(ALP)andβ-1,4-glucosidas(βG)were significantly higher in E.rhytidosperma and S.tianschanica var.gobica communities than in other plant communities(P<0.05).The topsoil had higher POC and MAOC contents than the subsoil.Specifically,the content of POC in the topsoil was 18.17%–42.73%higher than that in the subsoil.The structural equation model(SEM)indicated that plant species diversity,soil pH,and soil water content(SWC)were the main factors influencing POC and MAOC.The soil pH inhibited the formation of POC and promoted the formation of MAOC.Conversely,SWC stimulated POC production and hindered MAOC formation.Our study aimed to gain insight into the effects of desert plant communities on soil enzyme activities and SOC fractions,as well as the drivers of SOC fractions in the proluvial fan in the eastern foothills of the Helan Mountain and other desert ecosystems.
基金supported by the National Natural Science Foundation of China (31872856)the National Key Research and Development Program of China (2016YFD030020205)
文摘Legume cultivars affect N uptake,component crop growth,and soil physical and chemical characteristics in maize-legume intercropping systems.However,how belowground interactions mediate root growth,N fixation,and nodulation of different legumes to affect N uptake is still unclear.Hence,a two-year experiment was conducted with five planting patterns,i.e.,maize-soybean strip intercropping(IMS),maize-peanut strip intercropping(IMP),and corresponding monocultures(monoculture maize(MM),monoculture soybean(MS),and monoculture peanut(MP)),and two N application rates,i.e.,no N fertilizer(N-)and conventional N fertilizer(N+),to examine relationships between N uptake and root distribution of crops,legume nodulation and soil N availability.Results showed that the averaged N uptake per unit area of intercrops was significantly lower than the corresponding monocultures.Compared with the monoculture system,the N uptake of the intercropping systems increased by 31.7-45.4%in IMS and by 7.4-12.2%in IMP,respectively.The N uptake per plant of intercropped maize and soybean significantly increased by 61.6 and 31.8%,and that of intercropped peanuts significantly decreased by 46.6%compared with the corresponding monocultures.Maize and soybean showed asymmetrical distribution of roots in strip intercropping systems.The root length density(RLD)and root surface area density(RSAD)of intercropped maize and soybean were significantly greater than that of the corresponding monocultures.The roots of intercropped peanuts were confined,which resulted in decreased RLD and RSAD compared with the monoculture.The nodule number and nodule fresh weight of soybean were significantly greater in IMS than in MS,and those of peanut were significantly lower in IMP than in MP.The soil protease,urease,and nitrate reductase activities of maize and soybean were significantly greater in IMS and IMP than in the corresponding monoculture,while the enzyme activities of peanut were significantly lower in IMP than in MP.The soil available N of maize and soybean was significantly greater increased in IMS and IMP than in the corresponding monocultures,while that of IMP was significantly lower than in MP.In summary,the IMS system was more beneficial to N uptake than the IMP system.The intercropping of maize and legumes can promote the N uptake of maize,thus reducing the need for N application and improving agricultural sustainability.
基金supported by the National Natural Science Foundation of China(No.31460196 and 31870461)the Innovation Project of Guangxi Graduate Education(No.YCBZ2018012),the“Hundred Talent Program”of South China Botanical Garden at the Chinese Academy of Sciences(No.Y761031001)+1 种基金the“Young Top-notch Talent”in Pearl River talent plan of Guangdong Provinceby the Science(No.2019QN01L763).
文摘Background:There is substantial evidence that Eucalyptus for nitrogen(N)absorption and increasing the growth benefit from the introduction of N-fixing species,but the underlying mechanisms for microbially mediated soil N cycling remains unclear.Methods:We investigated the changes of soil pH,soil water content(SWC),soil organic carbon(SOC),total N(TN),inorganic N(NH_(4)^(+)-N and NO_(3)^(-)-N),microbial biomass and three N-degrading enzyme activities as well as the biomass and N productivity of Eucalyptus between a pure Eucalyptus urophylla×grandis plantation(PP)and a mixed Dalbergia odorifera and Eucalyptus plantation(MP)in Guangxi Zhuang Autonomous Region,China.Results:Compared with the PP site,soil pH,SWC,SOC and TN in both seasons were significantly higher at the MP site,which in turn enhanced microbial biomass and the activities of soil N-degrading enzymes.The stimulated microbial activity at the MP site likely accelerate soil N mineralization,providing more available N(NH_(4)^(+)-N in both seasons and NO_(3)^(-)-N in the wet-hot season)for Eucalyptus absorption.Overall,the N productivity of Eucalyptus at the MP site was increased by 19.7% and 21.9%,promoting the biomass increases of 15.1% and 19.2% in the drycold season and wet-hot season,respectively.Conclusion:Our results reveal the importance of microbially mediated soil N cycling in the N absorption on Eucalyptus.Introduction of D.odorifera enhances Eucalyptus biomass and N productivity,improve soil N availability and increased soil C and N concentration,which hence can be considered to be an effective sustainable management option of Eucalyptus plantations.
文摘Soil microbial biomass carbon (MBC), β-glucosidase, acid phosphatase and fluorescein diacetate (FDA) activities and bacterial community structure were assessed in a long-term (26 years) experiment, at physiological stages of sorghum growth, comparing different management methods for organic (manure, straw residues) and inorganic (urea) amendments at the INERA field station in Saria (Burkina Faso). Annual application of manure led to the highest soil microbial biomass and enzyme activities. Investigations indicated that only microbial biomass and β-glucosidase activities were affected during the cropping season. Phosphatase and FDA enzyme activities did not depend on the crop development stages. The application of N fertilizer modified phosphatase and FDA enzyme activities, the activities being higher in soils amended with N fertilizer. The bacterial community structure was analyzed by PCR-denaturing gradient gel electrophoresis (PCR-DGGE) targeting the eubacterial 16S rRNA gene. Cluster analysis of PCR-DGGE patterns showed two major clusters, the first containing the mineral fertilization and straw treatments and the second, the straw + urea, manure and manure + urea treatments. Sorghum grain yields were the highest for manure treatments. In this long-term experiment, applying straw did not produce a better grain yield than that obtained in the un-amended plot.
基金supported by the Major Basic Research Projects of Natural Science Foundation of Shandong(Grant No.ZR2018ZC2363).
文摘Lead(Pb)pollution is one of the most widespread and harmful environmental problems worldwide.Determination of changes in soil properties and microbial functional diversity due to land use is needed to establish a basis for remediation of soil pollution.This study aimed to investigate soils contaminated by Pb from different sources and to analyze the functional diversity and metabolism of soil microbial communities using Biolog technology.Pb pollution(>300 mg kg-1)significantly influenced the diversity and metabolic functions of soil microbial communities.Specifically,Pb contamination significantly reduced soil microbial biomass carbon(C)and nitrogen(N)levels and catalase activity while increasing invertase activity.Furthermore,Biolog EcoPlate assays revealed that Pb pollution reduced the general activities of soil microorganisms,suppressing their ability to utilize C sources.In Pb-contaminated areas lacking vegetation cover,Shannon,Simpson,and McIntosh diversity indices of soil microorganisms were significantly reduced.The microbial diversity and biomass C and N levels were affected by land use and soil properties,respectively,whereas soil enzyme activity was primarily affected by the interaction between land use and soil properties.Our results provide a reference and a theoretical basis for developing soil quality evaluation and remediation strategies.
