Analyses of microbial properties in soil and manure had always included the problem that there was no available standard method to evaluate microbial property. The one of the major problems was the vast diversity and ...Analyses of microbial properties in soil and manure had always included the problem that there was no available standard method to evaluate microbial property. The one of the major problems was the vast diversity and the enormous population of soil microorganisms [1], the other was an existence of numerically dominant unculturable microorganisms which comprise 99% of soil habitat [2]. We evaluated whether our newly developed method, by which taxonomies and their number of each bacterial groups were estimated, could be used as evaluation method of microbial properties of soils and manures. In the forest soil, β-Proteobacteria, which included Burkholderia sp., Ralstonia sp., and Alcaligenes sp., was numerically dominant bacteria (3.64 × 10<sup>6</sup> MPN g<sup>-1</sup> dry soil), followed by γ-Proteobacteria (1.32 × 10<sup>6</sup> MPN), δ-Proteobacteria (0.006 × 10<sup>6</sup> MPN), and the other gram negative bacteria (0.006 × 10<sup>6</sup> MPN). In the commercial manure, Actinobacteria, which included Streptoverticillium salmonis, Mycrococcus sp., Streptomyces bikiniensis, and Microbacterium ulmi, was numerically dominant bacterial group (30.8 × 10<sup>6</sup> MPN), followed by α-Proteobacteria (26.0 × 10<sup>6</sup> MPN), β-Proteobacteria (17.1 × 10<sup>6</sup> MPN), δ-Proteobacteria (11.2 × 10<sup>6</sup> MPN), the other Firmicutes (1.71 × 10<sup>6</sup> MPN), γ-Proteobacteria (0.5 × 10<sup>6</sup> MPN), and the other gram negative bacteria (0.05 × 10<sup>6</sup> MPN). In the upland field, the other Firmicutes, which included Paenibacillus sp., was numerically dominant bacteria (4.41 × 10<sup>6</sup> MPN), followed by Actinobacteria (2.14 × 10<sup>6</sup> MPN), Bacillus sp. (2.14 × 10<sup>6</sup> MPN), and γ-Proteobacteria (0.35 × 10<sup>6</sup> MPN). Although the precision of the affiliations became lower because of higher diversity of samples and the number of some Antinobacteria and Firmicutes might be underestimated by the used PCR condition, the method was found suitable as a candidate of a new evaluation system of soil and manure.展开更多
A field experiment with rice-rice rotation was conducted since 2002 in southeast China for investigating the response of soil microbial properties to intensive nitrogen fertilizer application. The tested soil was a su...A field experiment with rice-rice rotation was conducted since 2002 in southeast China for investigating the response of soil microbial properties to intensive nitrogen fertilizer application. The tested soil was a subtropical paddy soil derived from Quaternary red clay. Differences between treatments existed in different application rates of urea when the experiment was designed. Urea was applied in five rates, i.e., 0, 0.5, 1, 1.5, and 2 U, equivalent to 0, 0.5, 1, 1.5, and 2 times the local average amount of urea application （900 kg urea ha-~ yr-~, equivalent to 414 kg N ha-1 yr-~）. In 2007, soil total nitrogen, available nitrogen, and soil organic carbon contents were increased by 10.2-27.9, 8.0-16.0, and 10.2-30.6%, respectively, in treatments with urea application rates of 0.5 to 2 U compared to control （0 U）. Microbial biomass carbon and nitrogen were also increased by 3.1-30.8 and 1.3-13.9%, respectively, in treatments with urea application. Basal respiration in treatments with urea input were 9.4-29.1% higher than that in control. However, changes of bacterial functional diversity had different trends. Urea fertilization enhanced bacterial functional diversity until treatment of 1 U, but re-decreased it from treatment of 1.5 U. Principal components analysis indicated that there were intimate relationships among soil organic matter, nitrogen nutrient, microbial biomass, and respiration. Nevertheless, microbial diversity was related to soil moisture contents after urea application. We conclude here that the application of N fertilizer improved soil microbial biomass and respiratory activity. But, microbial diversity was reduced when excessive urea was applied in the tested paddy soil.展开更多
In this study, we selected yttrium as the representative of REEs to investigate the impacts of exogenous yttrium on soil physicochemical properties and microbiota. The results showed that exogenous yttrium has no sign...In this study, we selected yttrium as the representative of REEs to investigate the impacts of exogenous yttrium on soil physicochemical properties and microbiota. The results showed that exogenous yttrium has no significant effect on soil physical properties but a significantly negative impact on soil chemical properties. The results of high-throughput sequencing demonstrate that exogenous yttrium significantly decreases the number of OTUs, ACE, Chao 1, and Shannon indices while increases the Simpson index（P 〈 0.05）, indicating the low soil microbial diversity. The relative abundances of soil microbes are significantly changed at phylum and genus level. Principal component analysis（PCA） showed the significant difference of microbial community between yttrium treatments（YCl_3-250 and YCl_3-500） and non-yttrium treatment（CK） and the similarity of that between YCl_3-250 and YCI_3-500. Proteobacteria and Bacteroidetes are found to be the most tolerant phyla to exogenous yttrium while Verrucomicrobia the most sensitive phylum. Redundancy analysis（RDA） results suggest that exogenous yttrium affects soil microbiota only through changing the soil chemical properties but not soil physical properties, and C/N ratio is the key environmental factor.展开更多
Brazilian industry produces huge amounts of tannery sludge as residues,which is often disposed by landfilling or land application.However,consecutive amendment of such composted industrial wastes may cause shifts in s...Brazilian industry produces huge amounts of tannery sludge as residues,which is often disposed by landfilling or land application.However,consecutive amendment of such composted industrial wastes may cause shifts in soil microbial biomass(SMB) and enzyme activity.This study aimed to evaluate SMB and enzyme activity after 3-year consecutive composted tannery sludge(CTS) amendment in tropical sandy soils.Different amounts of CTS(0.0,2.5,5.0,10.0,and 20.0 t ha^(-1)) were applied to a sandy soil.The C and N contents of SMB,basal and substrate-induced respiration,respiratory quotient(qCO_2),and enzyme activities were determined in the soil samples collected after CTS amendment for 60 d at the third year.After 3 years,significant changes were found in soil microbial properties in response to different CTS amounts applied.The organic matter and Cr contents significantly increased with increasing CTS amounts.SMB and soil respiration peaked following amendment with 10.0 and 20.0 t ha-1 of CTS,respectively,while qCO_2was not significantly affected by CTS amendment.However,soil enzyme activity decreased significantly with increasing CTS amounts.Consecutive CTS amendment for 3 years showed inconsistent and contrasting effects on SMB and enzyme activities.The decrease in soil enzyme activities was proportional to a substantial increase in soil Cr concentration,with the latter exceeding the permitted concentrations by more than twofold.Thus,our results suggest that a maximum CTS quantity of 5.0 t ha^(-1) can be applied annually to tropical sandy soil,without causing potential risks to SMB and enzyme activity.展开更多
The importance of soil organic carbon （SOC） under forests in the global carbon cycle depends on the stability of the soil carbon and its availability to soil microbial biomass. We investigated the effects of success...The importance of soil organic carbon （SOC） under forests in the global carbon cycle depends on the stability of the soil carbon and its availability to soil microbial biomass. We investigated the effects of successive rotations of Chinese fir （Cunninghamia lanceolata （Lamb.） Hook） plantations on the stability of SOC and its availability to microbes by adopting the two-step hydrolysis with H2SO4 and density fractionation. The results showed that successive rotations of Chinese fir decreased the quantity of total SOC, recalcitrant fraction, and carbohydrates in Labile Pool I （LPI）, and microbial properties evidently, especially at 0-10 cm horizon. However, cellulose included in Labile Pool Ⅱ （LP Ⅱ） and the cellulose/total carbohydrates ratio increased in successive rotations of Chinese fir. The noncellulose of carbohydrates included in LPI maybe highly available to soil microbial biomass. Hence the availability of SOC to microbial biomass declined over the successive rotations. Although there was no significant change in recalcitrance of SOC over the successive rotations of Chinese fir, the percentage of heavy fraction to total SOC increased, suggesting that the degree of physical protection for SOC increased and SOC became more stable over the successive rotations. The degradation of SOC quality in successive rotation soils may be attributed to worse environmental conditions resulted from disturbance that related to ＂slash and burn＂ site preparation. Being highly correlated with soil microbial properties, the cellulose/total carbohydrates ratio as an effective indicator of changes in availability of SOC to microbial biomass brought by management practices in forest soils.展开更多
Understanding the age effect on soil carbon balance in forest ecosystems is important for other material cycles and forest man-agement. In this research we investigated soil organic carbon density, litter production, ...Understanding the age effect on soil carbon balance in forest ecosystems is important for other material cycles and forest man-agement. In this research we investigated soil organic carbon density, litter production, litter decomposition rate, soil respiration, and soil mi-crobial properties in a chronosequence of four Chinese fir plantations of 7, 16, 23 and 29 years at Dagangshan mountain range, Jiangxi Province, south China. There was a significant increasing trend in litter production with increasing plantation age. Litter decomposition rate and soil respira-tion, however, declined from the 7-year to the 16-year plantation, and then increased after 16 years. This was largely dependent on soil micro-organisms. Soil carbon output was higher than carbon input before 16 years, and total soil carbon stock declined from 35.98 t＆#183;ha-1 in the 7-year plantation to 30.12 t＆#183;ha-1 in the 16-year plantation. Greater litter produc-tion could not explain the greater soil carbon stock, suggesting that forest growth impacted this microbial process that controlled rates of soil car-bon balance together with litter and soil respiration. The results highlight＆amp;nbsp;the importance of the development stage in assessing soil carbon budget and its significance to future management of Chinese fir plantations.展开更多
The decay rate of standing Korean pine(Pinus koraiensis)in natural forests can be as high as 50%and is likely infl uenced by the soil properties and nutrient and water status of the site.To clarify the relationship be...The decay rate of standing Korean pine(Pinus koraiensis)in natural forests can be as high as 50%and is likely infl uenced by the soil properties and nutrient and water status of the site.To clarify the relationship between the severity of tree decay and soil properties in order to prevent decay in a natural mixed forest in the Xiaoxing'an Mountains,wood strength of standing trees was nondestructively assessed,and the severity of decay of extracted wood cores was quantified based on differences in mass between two decayed increment cores extracted at breast height and an intact increment core near the decayed ones.Soil samples from the critical root zone(non-rhizosphere)of each tree were analyzed for chemical properties and microbial composition.The abundance of chemical elements(especially total N and K)and the species richness of soil microbes increased as decay severity increased.Fungal number(FN)and actinomycetes number(AN)were related to decay severity(R^(2)=0.504).Bacterial number(BN)was higher than FN or AN,but had a minor effect on tree decay.Path analysis showed BN might indirectly inhibit decay by affecting FN.Decay severity was not significantly correlated with either soil fungal or bacterial diversity.These results suggest that forest managers need to monitor levels of fungi and total N and total K levels to reduce the decay of Korean pine.展开更多
In spite of the relevance of current studies on the importance of organic fertilizers such as animal manure in improving the health of ecosystems, little is known about the biochemical mechanisms affecting the availab...In spite of the relevance of current studies on the importance of organic fertilizers such as animal manure in improving the health of ecosystems, little is known about the biochemical mechanisms affecting the availability of nutrients released from the organic fertilizer in water. A litter bag study during 6 weeks was carried out in pots containing 25 liters of water with 15 g of pig dejections as organic fertilizers. The experimental design was a completely randomized block design with three replications. The treatments consisted of dejections of pigs nourished with: recommended diet composition T1, partially improved diet with Azolla filiculoides T2, improved diet with Azolla filiculoides T3, improved diet with cereal bran T4. A control treatment without dejection (T0) was considered in the study for comparison purpose. Four pigs per type of diet were considered leading to 16 white landrace pigs of six months age followed for dejection collections. Strong release of nutrients for better yield for agro-fish system was obtained in the manure T1 with ??(10.85 ± 0.00) mg/L;?( 0.011 ± 0.00) mg/L;?(2.13 ± 0.07) mg/L and K+ (10.76 ± 0.57) mg/L;Ca2+ (2.92 ± 0.11) mg/L and Mg2+ (2.53 ± 0.00) mg/L followed by manure T3 and T4 with high N content. The relatively low ratio C/N (14.25) for T1 and (15.84) for T3 induced more nutrients releasing. This study showed an important N loss probably due to microorganism activities which fluctuate nutrient availability. Also significant correlations were noted between the nutrient dynamics in water and physicochemical parameters showing the effect of abiotic factors on organic matter decomposition and mineralization which depend on microbial activities in water and pig manure composition.展开更多
Subsoils hold a substantial reservoir of organic carbon(C),and its dynamics can be greatly influenced by fresh C inputs through priming effect,potentially altering the magnitude of soil C-climate feedback.Despite the ...Subsoils hold a substantial reservoir of organic carbon(C),and its dynamics can be greatly influenced by fresh C inputs through priming effect,potentially altering the magnitude of soil C-climate feedback.Despite the importance of soil C dynamics in regulating this feedback,our understanding of how soil C release and the priming effect vary along the soil profile remains limited,especially in alpine grasslands on the Tibetan Plateau.In particular,the relative importance of abiotic and biotic factors,such as soil physicochemical properties,aggregate and mineral protection,substrate quantity and quality,and plant and microbial properties(e.g.,microbial biomass and diversity),in mediating vertical variations in soil C release and the priming effect is still unclear.Using 1-meter-deep soil profiles from five sites on the plateau,our~(13)C isotope labeling incubation experiments revealed a significant decline in both C release and the priming effect with increasing soil depth.We found that variations in soil C release along the profile were primarily influenced by soil properties(soil moisture and p H),mineral protection(the molar ratios of amorphous Fe/Al oxides to soil organic C(SOC)and soil mineral specific surface area),and hydrolase activity.In addition,vertical variations in the priming effect were dominantly affected by soil properties(soil moisture and p H),mineral and aggregate protection(the molar ratio of exchangeable Ca to SOC and the proportion of C occluded in clay+silt fractions),and microbial properties(oxidase activity and the copy number of bacterial ribosomal RNA gene operons).These findings provide valuable insights into the complex soil C cycling across profiles and its feedback to climate change.展开更多
Agriculture uses a large proportion of global and regional water resources.Due to the rapid increase of population in the world,the increasing competition for water resources has led to an urgent need in increasing cr...Agriculture uses a large proportion of global and regional water resources.Due to the rapid increase of population in the world,the increasing competition for water resources has led to an urgent need in increasing crop water productivity for agricultural sustainability.As the medium for crop growth,soils and their properties are important in affecting crop water productivity.This review examines the effects of soil physical,chemical,and microbial properties on crop water productivity and the quantitative relationships between them.A comprehensive view of these relationships may provide important insights for soil and water management in arable land for agriculture in the future.展开更多
文摘Analyses of microbial properties in soil and manure had always included the problem that there was no available standard method to evaluate microbial property. The one of the major problems was the vast diversity and the enormous population of soil microorganisms [1], the other was an existence of numerically dominant unculturable microorganisms which comprise 99% of soil habitat [2]. We evaluated whether our newly developed method, by which taxonomies and their number of each bacterial groups were estimated, could be used as evaluation method of microbial properties of soils and manures. In the forest soil, β-Proteobacteria, which included Burkholderia sp., Ralstonia sp., and Alcaligenes sp., was numerically dominant bacteria (3.64 × 10<sup>6</sup> MPN g<sup>-1</sup> dry soil), followed by γ-Proteobacteria (1.32 × 10<sup>6</sup> MPN), δ-Proteobacteria (0.006 × 10<sup>6</sup> MPN), and the other gram negative bacteria (0.006 × 10<sup>6</sup> MPN). In the commercial manure, Actinobacteria, which included Streptoverticillium salmonis, Mycrococcus sp., Streptomyces bikiniensis, and Microbacterium ulmi, was numerically dominant bacterial group (30.8 × 10<sup>6</sup> MPN), followed by α-Proteobacteria (26.0 × 10<sup>6</sup> MPN), β-Proteobacteria (17.1 × 10<sup>6</sup> MPN), δ-Proteobacteria (11.2 × 10<sup>6</sup> MPN), the other Firmicutes (1.71 × 10<sup>6</sup> MPN), γ-Proteobacteria (0.5 × 10<sup>6</sup> MPN), and the other gram negative bacteria (0.05 × 10<sup>6</sup> MPN). In the upland field, the other Firmicutes, which included Paenibacillus sp., was numerically dominant bacteria (4.41 × 10<sup>6</sup> MPN), followed by Actinobacteria (2.14 × 10<sup>6</sup> MPN), Bacillus sp. (2.14 × 10<sup>6</sup> MPN), and γ-Proteobacteria (0.35 × 10<sup>6</sup> MPN). Although the precision of the affiliations became lower because of higher diversity of samples and the number of some Antinobacteria and Firmicutes might be underestimated by the used PCR condition, the method was found suitable as a candidate of a new evaluation system of soil and manure.
基金supported by the National Basic Research Program of China (973 Program,2007CB109301)the National Key Technology R & D Program of China (2009BADC6B03)Asia-Europe Link Project (CN-Asia-Link-001,81468)
文摘A field experiment with rice-rice rotation was conducted since 2002 in southeast China for investigating the response of soil microbial properties to intensive nitrogen fertilizer application. The tested soil was a subtropical paddy soil derived from Quaternary red clay. Differences between treatments existed in different application rates of urea when the experiment was designed. Urea was applied in five rates, i.e., 0, 0.5, 1, 1.5, and 2 U, equivalent to 0, 0.5, 1, 1.5, and 2 times the local average amount of urea application （900 kg urea ha-~ yr-~, equivalent to 414 kg N ha-1 yr-~）. In 2007, soil total nitrogen, available nitrogen, and soil organic carbon contents were increased by 10.2-27.9, 8.0-16.0, and 10.2-30.6%, respectively, in treatments with urea application rates of 0.5 to 2 U compared to control （0 U）. Microbial biomass carbon and nitrogen were also increased by 3.1-30.8 and 1.3-13.9%, respectively, in treatments with urea application. Basal respiration in treatments with urea input were 9.4-29.1% higher than that in control. However, changes of bacterial functional diversity had different trends. Urea fertilization enhanced bacterial functional diversity until treatment of 1 U, but re-decreased it from treatment of 1.5 U. Principal components analysis indicated that there were intimate relationships among soil organic matter, nitrogen nutrient, microbial biomass, and respiration. Nevertheless, microbial diversity was related to soil moisture contents after urea application. We conclude here that the application of N fertilizer improved soil microbial biomass and respiratory activity. But, microbial diversity was reduced when excessive urea was applied in the tested paddy soil.
基金Project supported by the National Science&Technology Pilslar Program of China during the Twelfth Five-year Plan Period(2012BAC11B07)National Science&Technology Benefiting Program of China(2013GS360203)+5 种基金"Gan Po 555 Project"Leading Talents Training Program,Outstanding Doctoral Dissertation Project Fund of JXUST(YB2016005)Innovation Special Fund for Graduate of Jiangxi Province(YC2014-B059)the Sciences&Technologies Landing Plan of Jiangxi Province for Universities(KJLD14042)the Technology Support Plan of Jiangxi Province(20151BBG70005)the National Natural Science Foundation of China(51564023,21407070)High-end Foreign Experts Project(GDW20177200147)
文摘In this study, we selected yttrium as the representative of REEs to investigate the impacts of exogenous yttrium on soil physicochemical properties and microbiota. The results showed that exogenous yttrium has no significant effect on soil physical properties but a significantly negative impact on soil chemical properties. The results of high-throughput sequencing demonstrate that exogenous yttrium significantly decreases the number of OTUs, ACE, Chao 1, and Shannon indices while increases the Simpson index（P 〈 0.05）, indicating the low soil microbial diversity. The relative abundances of soil microbes are significantly changed at phylum and genus level. Principal component analysis（PCA） showed the significant difference of microbial community between yttrium treatments（YCl_3-250 and YCl_3-500） and non-yttrium treatment（CK） and the similarity of that between YCl_3-250 and YCI_3-500. Proteobacteria and Bacteroidetes are found to be the most tolerant phyla to exogenous yttrium while Verrucomicrobia the most sensitive phylum. Redundancy analysis（RDA） results suggest that exogenous yttrium affects soil microbiota only through changing the soil chemical properties but not soil physical properties, and C/N ratio is the key environmental factor.
基金Supported by the Conselho Nacional de Desenvolvimento Cientifico e Tecnológico,Brazil(No.302999/2011-6)the Fundacao de Amparo a Pesquisa do Estado do Piaui,Brazil(No.032/2011)
文摘Brazilian industry produces huge amounts of tannery sludge as residues,which is often disposed by landfilling or land application.However,consecutive amendment of such composted industrial wastes may cause shifts in soil microbial biomass(SMB) and enzyme activity.This study aimed to evaluate SMB and enzyme activity after 3-year consecutive composted tannery sludge(CTS) amendment in tropical sandy soils.Different amounts of CTS(0.0,2.5,5.0,10.0,and 20.0 t ha^(-1)) were applied to a sandy soil.The C and N contents of SMB,basal and substrate-induced respiration,respiratory quotient(qCO_2),and enzyme activities were determined in the soil samples collected after CTS amendment for 60 d at the third year.After 3 years,significant changes were found in soil microbial properties in response to different CTS amounts applied.The organic matter and Cr contents significantly increased with increasing CTS amounts.SMB and soil respiration peaked following amendment with 10.0 and 20.0 t ha-1 of CTS,respectively,while qCO_2was not significantly affected by CTS amendment.However,soil enzyme activity decreased significantly with increasing CTS amounts.Consecutive CTS amendment for 3 years showed inconsistent and contrasting effects on SMB and enzyme activities.The decrease in soil enzyme activities was proportional to a substantial increase in soil Cr concentration,with the latter exceeding the permitted concentrations by more than twofold.Thus,our results suggest that a maximum CTS quantity of 5.0 t ha^(-1) can be applied annually to tropical sandy soil,without causing potential risks to SMB and enzyme activity.
基金supported by the National Natural Sci-ence Foundation of China (No. 30470303)the Key Project of the Knowledge Innovation Program of the Chinese Academy of Sciences (No. KZCX2-YW-405)
文摘The importance of soil organic carbon （SOC） under forests in the global carbon cycle depends on the stability of the soil carbon and its availability to soil microbial biomass. We investigated the effects of successive rotations of Chinese fir （Cunninghamia lanceolata （Lamb.） Hook） plantations on the stability of SOC and its availability to microbes by adopting the two-step hydrolysis with H2SO4 and density fractionation. The results showed that successive rotations of Chinese fir decreased the quantity of total SOC, recalcitrant fraction, and carbohydrates in Labile Pool I （LPI）, and microbial properties evidently, especially at 0-10 cm horizon. However, cellulose included in Labile Pool Ⅱ （LP Ⅱ） and the cellulose/total carbohydrates ratio increased in successive rotations of Chinese fir. The noncellulose of carbohydrates included in LPI maybe highly available to soil microbial biomass. Hence the availability of SOC to microbial biomass declined over the successive rotations. Although there was no significant change in recalcitrance of SOC over the successive rotations of Chinese fir, the percentage of heavy fraction to total SOC increased, suggesting that the degree of physical protection for SOC increased and SOC became more stable over the successive rotations. The degradation of SOC quality in successive rotation soils may be attributed to worse environmental conditions resulted from disturbance that related to ＂slash and burn＂ site preparation. Being highly correlated with soil microbial properties, the cellulose/total carbohydrates ratio as an effective indicator of changes in availability of SOC to microbial biomass brought by management practices in forest soils.
基金funded by the Special Fund for Forestry Scientific Research in the Public Interest(No.201104009-02)
文摘Understanding the age effect on soil carbon balance in forest ecosystems is important for other material cycles and forest man-agement. In this research we investigated soil organic carbon density, litter production, litter decomposition rate, soil respiration, and soil mi-crobial properties in a chronosequence of four Chinese fir plantations of 7, 16, 23 and 29 years at Dagangshan mountain range, Jiangxi Province, south China. There was a significant increasing trend in litter production with increasing plantation age. Litter decomposition rate and soil respira-tion, however, declined from the 7-year to the 16-year plantation, and then increased after 16 years. This was largely dependent on soil micro-organisms. Soil carbon output was higher than carbon input before 16 years, and total soil carbon stock declined from 35.98 t＆#183;ha-1 in the 7-year plantation to 30.12 t＆#183;ha-1 in the 16-year plantation. Greater litter produc-tion could not explain the greater soil carbon stock, suggesting that forest growth impacted this microbial process that controlled rates of soil car-bon balance together with litter and soil respiration. The results highlight＆amp;nbsp;the importance of the development stage in assessing soil carbon budget and its significance to future management of Chinese fir plantations.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.31870537 and 31570547)the Fundamental Research Funds for the Central Universities of China(Grant No.2572018BL08)the Research and Development Project of Application Technology in Harbin(Grant No.2017RAQXJ078)。
文摘The decay rate of standing Korean pine(Pinus koraiensis)in natural forests can be as high as 50%and is likely infl uenced by the soil properties and nutrient and water status of the site.To clarify the relationship between the severity of tree decay and soil properties in order to prevent decay in a natural mixed forest in the Xiaoxing'an Mountains,wood strength of standing trees was nondestructively assessed,and the severity of decay of extracted wood cores was quantified based on differences in mass between two decayed increment cores extracted at breast height and an intact increment core near the decayed ones.Soil samples from the critical root zone(non-rhizosphere)of each tree were analyzed for chemical properties and microbial composition.The abundance of chemical elements(especially total N and K)and the species richness of soil microbes increased as decay severity increased.Fungal number(FN)and actinomycetes number(AN)were related to decay severity(R^(2)=0.504).Bacterial number(BN)was higher than FN or AN,but had a minor effect on tree decay.Path analysis showed BN might indirectly inhibit decay by affecting FN.Decay severity was not significantly correlated with either soil fungal or bacterial diversity.These results suggest that forest managers need to monitor levels of fungi and total N and total K levels to reduce the decay of Korean pine.
基金the Scientific Council of the University of Abomey-Calavi,which funded the project untitled“Optimization of Agricultural Production Integrated System without Inputs(OPASISI)”in which this research work has been undertaken.
文摘In spite of the relevance of current studies on the importance of organic fertilizers such as animal manure in improving the health of ecosystems, little is known about the biochemical mechanisms affecting the availability of nutrients released from the organic fertilizer in water. A litter bag study during 6 weeks was carried out in pots containing 25 liters of water with 15 g of pig dejections as organic fertilizers. The experimental design was a completely randomized block design with three replications. The treatments consisted of dejections of pigs nourished with: recommended diet composition T1, partially improved diet with Azolla filiculoides T2, improved diet with Azolla filiculoides T3, improved diet with cereal bran T4. A control treatment without dejection (T0) was considered in the study for comparison purpose. Four pigs per type of diet were considered leading to 16 white landrace pigs of six months age followed for dejection collections. Strong release of nutrients for better yield for agro-fish system was obtained in the manure T1 with ??(10.85 ± 0.00) mg/L;?( 0.011 ± 0.00) mg/L;?(2.13 ± 0.07) mg/L and K+ (10.76 ± 0.57) mg/L;Ca2+ (2.92 ± 0.11) mg/L and Mg2+ (2.53 ± 0.00) mg/L followed by manure T3 and T4 with high N content. The relatively low ratio C/N (14.25) for T1 and (15.84) for T3 induced more nutrients releasing. This study showed an important N loss probably due to microorganism activities which fluctuate nutrient availability. Also significant correlations were noted between the nutrient dynamics in water and physicochemical parameters showing the effect of abiotic factors on organic matter decomposition and mineralization which depend on microbial activities in water and pig manure composition.
基金supported by the National Key Research and Development Program of China(2022YFF0801901)the National Natural Science Foundation of China(32425004)the New Cornerstone Science Foundation through the XPLORER PRIZE。
文摘Subsoils hold a substantial reservoir of organic carbon(C),and its dynamics can be greatly influenced by fresh C inputs through priming effect,potentially altering the magnitude of soil C-climate feedback.Despite the importance of soil C dynamics in regulating this feedback,our understanding of how soil C release and the priming effect vary along the soil profile remains limited,especially in alpine grasslands on the Tibetan Plateau.In particular,the relative importance of abiotic and biotic factors,such as soil physicochemical properties,aggregate and mineral protection,substrate quantity and quality,and plant and microbial properties(e.g.,microbial biomass and diversity),in mediating vertical variations in soil C release and the priming effect is still unclear.Using 1-meter-deep soil profiles from five sites on the plateau,our~(13)C isotope labeling incubation experiments revealed a significant decline in both C release and the priming effect with increasing soil depth.We found that variations in soil C release along the profile were primarily influenced by soil properties(soil moisture and p H),mineral protection(the molar ratios of amorphous Fe/Al oxides to soil organic C(SOC)and soil mineral specific surface area),and hydrolase activity.In addition,vertical variations in the priming effect were dominantly affected by soil properties(soil moisture and p H),mineral and aggregate protection(the molar ratio of exchangeable Ca to SOC and the proportion of C occluded in clay+silt fractions),and microbial properties(oxidase activity and the copy number of bacterial ribosomal RNA gene operons).These findings provide valuable insights into the complex soil C cycling across profiles and its feedback to climate change.
基金partially supported by the National Natural Science Foundation of China(51725904,51861125103)the Research Projects of Agricultural Public Welfare Industry in China(201503125)the Discipline Innovative Engineering Plan(111 Program,B14002)。
文摘Agriculture uses a large proportion of global and regional water resources.Due to the rapid increase of population in the world,the increasing competition for water resources has led to an urgent need in increasing crop water productivity for agricultural sustainability.As the medium for crop growth,soils and their properties are important in affecting crop water productivity.This review examines the effects of soil physical,chemical,and microbial properties on crop water productivity and the quantitative relationships between them.A comprehensive view of these relationships may provide important insights for soil and water management in arable land for agriculture in the future.
