This study aimed to explore the effect of different proportions of organic fertilizer replacing chemical fertilizer on the bacterial community and metabolic function in paddy fields.The 16S rRNA absolute quantitative ...This study aimed to explore the effect of different proportions of organic fertilizer replacing chemical fertilizer on the bacterial community and metabolic function in paddy fields.The 16S rRNA absolute quantitative sequencing method was employed to study the response characteristics of soil bacterial community composition and species absolute abundance to environmental factors under three fertilization treatments[chemical fertilizer(NPK),organic fertilizer replacing 30%of chemical fertilizer(30M,estimated in terms of pure nitrogen,same below),and organic fertilizer replacing 60%of chemical fertilizer(60M)]for two consecutive years.Furthermore,the changes of bacterial metabolic functions of different fertilization treatments were predicted by PICRUSt2.The results showed that replacing chemical fertilizer with organic fertilizer at different proportions significantly increased the total nitrogen(TN),total potassium(TK),hydrolyzable nitrogen(HN),soil organic carbon(SOC),and significantly decreased the soil bulk density(SBD).Moreover,60M demonstrated better performance than 30M.Different fertilization treatments did not cause significant difference in soil bacterial richness index(Chao1)or diversity index(Shannon)but significantly affected bacterial community composition and species abundance.Particularly,60M significantly increased the abundance of 227 species,and it increased the total bacterial abundance by 25.30%and 56.58%compared with NPK and 30M,respectively.Redundancy analysis and Spearman correlation analysis revealed that SOC,TN,and AK were the key factors for shaping specific bacterial community structures under different fertilization treatments.The 60M treatment significantly increased the abundance of bacterial species involved in xenobiotic biodegradation and metabolism,amino acid metabolism,and lipid metabolism,thus improving the metabolic functions of soil microorganisms.展开更多
In agricultural systems, maintenance of soil organic matter has long been recognized as a strategy to reduce soil degradation. Manure amendments and green manures are management practices that can increase some nutrie...In agricultural systems, maintenance of soil organic matter has long been recognized as a strategy to reduce soil degradation. Manure amendments and green manures are management practices that can increase some nutrient contents and improve soil aggregation. We investigated the effects of 28 yr of winter planted green manure on soil aggregate-size distribution and aggregateassociated carbon（C） and nitrogen（N）. The study was a randomized completed block design with three replicates. The treatments included rice-rice-fallow, rice-rice-rape, rice-rice-Chinese milk vetch and rice-rice-ryegrass. The experiment was established in 1982 on a silty light clayey paddy soil derived from Quaternary red clay（classified as Fe-Accumuli-Stagnic Anthrosols） with continuous early and late rice. In 2009, soil samples were collected（0-15 cm depth） from the field treatment plots and separated into water-stable aggregates of different sizes（i.e., 〉5, 2-5, 1-2, 0.5-1, 0.25-0.5 and 〈0.25 mm） by wet sieving. The long-term winter planted green manure significantly increased total C and N, and the formation of the 2-5-mm water-stable aggregate fraction. Compared with rice-rice-rape, rice-rice-Chinese milk vetch and rice-rice-ryegrass, the rice-rice-fallow significantly reduced 2-5-mm water-stable aggregates, with a significant redistribution of aggregates into micro-aggregates. Long-term winter planted green manure obviously improved C/N ratio and macro-aggregate-associated C and N. The highest contribution to soil fertility was from macro-aggregates of 2-5 mm in most cases.展开更多
Soil physical properties are important indicators of the potential for agricultural production.Our objective was to evaluate the effects of long-term inputs of green manures on physical properties of a reddish paddy s...Soil physical properties are important indicators of the potential for agricultural production.Our objective was to evaluate the effects of long-term inputs of green manures on physical properties of a reddish paddy soil（Fe-Typic Hapli-Stagnic Anthrosols） under a double cropping system.The common cropping pattern before the study was early-late rice-fallow（winter）.The field treatments included rice-rice-fallow（R-R-WF）,rice-rice-rape（R-R-RP）,rice-rice-Chinese milk vetch（RR-MV）,and rice-rice-ryegrass（R-R-RG）.The rape,Chinese milk vetch and ryegrass were all incorporated as green manures 15 d before early rice transplanting during the following year.The soil bulk density in all green manure treatments was significantly reduced compared with the winter fallow treatment.Soil porosity with green manure applications was significantly higher than that under the winter fallow.The green manure treatments had higher 0.25-5 mm water stable aggregates and aggregates stabilities in the plow layer（0-15 cm depth） compared with the fallow treatment.The mean weight diameter（MWD） and normalized mean weight diameter（NMWD） of aggregates in the green manure treatment were larger than that with the winter fallow.Soil given green manure retained both a higher water holding capacity in the plow layer soil,and a larger volume of moisture at all matric potentials（-10,-33 and-100 kPa）.We conclude that the management of double-rice fields in southern central China should be encouraged to use green manures along with chemical fertilizers to increase SOC content,improve soil physical properties and soil fertility.展开更多
Increasing K＋ adsorption can be an effective alternative in building an available K pool in soils to optimize crop recovery and minimize losses into the environment. We hypothesized that long-term fertilization might...Increasing K＋ adsorption can be an effective alternative in building an available K pool in soils to optimize crop recovery and minimize losses into the environment. We hypothesized that long-term fertilization might change K＋ adsorption because of changes in the chemical and mineralogical properties of a rice （Oryza sativa L.）. The aims of this study were （i） to determine clay minerals in paddy soil clay size fractions using X-ray diffraction methods and a numerical diagramdecomposition method; （ii） to measure K＋ adsorption isotherms before and after H202 oxidation of organic matter, and （iii） to investigate whether K＋ adsorption is correlated with changes in soil chemical and mineral properties. The 30-yr longterm fertilization treatments caused little change in soil organic C （SOC） but a large variation in soil mineral composition. The whole-clay fraction （〈5 Jam） corresponded more to the fertilization treatment than the fine-clay fraction （〈1 gin） in terms of percentage of illite peak area. The total percentage of vermiculite-chlorite peak area was significantly negatively correlated with the total percentage ofillite peak area in the 〈5 lam soil particles （R=-0.946, P〈0.0006）. Different fertilization treatments gave significantly different results in K＋ adsorption. The SOC oxidation test showed positive effects of SOC on K＋ adsorption at lower K＋ concentration （≤120 mg L-0 and negative effects at higher K＋ concentration （240 mg L-l）. The K＋ adsorption by soil clay minerals after SOC oxidization accounted for 60-158% of that by unoxidized soils, suggesting a more important role of soil minerals than SOC on K＋ adsorption. The K＋ adsorption potential was significantly correlated to the amount of poorly crystallized illite present （R--0.879, P=0.012）. The availability of adsorbed K＋ for plant growth needs further study.展开更多
Turbot(Scophthalmus maximus L.) reddish body iridovirus(TRBIV) was propagated in turbot fin cells(TF cells) and inactivated as the TRBIV vaccine with its protection efficiency evaluated in this study.TF cells were cul...Turbot(Scophthalmus maximus L.) reddish body iridovirus(TRBIV) was propagated in turbot fin cells(TF cells) and inactivated as the TRBIV vaccine with its protection efficiency evaluated in this study.TF cells were cultured in 10% bovine calf serum(BCS)-containing MEM medium(pH7.0) at 22℃,in which TRBIV propagated to a titer as high as 105.6 TCID50 mL-1.The TRBIV was inactivated with 0.1% formalin and formulated with 0.5% aluminum hydroxide.The inactivated vaccine caused neither cytopathogenic effect(CPE) on TF cells nor pathogenic effect on turbots.After being administered with the vaccine twice via muscle injection,the turbot developed high-tittered TRBIV neutralizing antibodies in a dose-dependent manner.The vaccine protected the turbot from dying with an immunoprotection rate of 83.3% as was determined via subcutaneous vaccination in the laboratory and 90.5% via bath vaccination in turbot farms,respectively.The inactivated vaccine was very immunogenic,efficiently preventing tur-bot from death.It holds the potential of being applied in aquaculture.展开更多
Environmental magnetic research on beaches and shoreline processes is limited.Therefore,we carried out environmental magnetic studies on the heavy mineral-enriched,dark-reddish sands on Cedar Beach of western Lake Eri...Environmental magnetic research on beaches and shoreline processes is limited.Therefore,we carried out environmental magnetic studies on the heavy mineral-enriched,dark-reddish sands on Cedar Beach of western Lake Erie(41.68°N,82.40°W).Magnetite has been identified as the dominant magnetic mineral of these sands.This study reveals a spatial variation in concentration of magnetite particles,distribution of展开更多
Environment-friendly pigments based on AFeO_(3)(A=La,Pr,Nd,Sm,Gd,Tb,Y or Yb)with high nearinfrared(NIR)reflectance were synthesised by a coprecipitation method at 1200℃.The Rietveld refinement analysis showed single-...Environment-friendly pigments based on AFeO_(3)(A=La,Pr,Nd,Sm,Gd,Tb,Y or Yb)with high nearinfrared(NIR)reflectance were synthesised by a coprecipitation method at 1200℃.The Rietveld refinement analysis showed single-phase orthorhombic perovskite for all compositions.All pigments,which showed reddish hues,offered good colour stability after mixing these pigments in powder form with siloxane transparent paint and two different glazes.The powderepaint mixtures produced with GdFeO_(3),TbFeO_(3) and YFeO_(3) pigments have the highest NIR solar reflectance,reaching values of R=50%.The temperature shielding studies conducted using TbFeO_(3) pigmentepaint mixture for a roof coating yielded a reduction of 3.2℃ in comparison to a commercial pigment.Moreover,the glazes that were pigmented using GdFeO_(3),TbFeO_(3) and YFeO_(3) compositions also presented the most intense reddish colours.A study of the thermal and chemical stability of the pigment with the highest NIR solar reflectance showed good stability in both cases.The reddish pigments that were prepared can therefore be good candidates for use in different applications such as cool pigments or pigments for ceramic glazes at high temperatures.展开更多
研究双季稻种植制度下长期不同施肥红壤性水稻土磷素含量及磷素有效性演变特征及其对土壤磷盈亏(磷平衡)的响应,为南方双季稻区红壤性水稻土科学施磷提供依据。以35年长期肥料定位试验为平台,研究不同施肥处理土壤全磷、有效磷及磷活化...研究双季稻种植制度下长期不同施肥红壤性水稻土磷素含量及磷素有效性演变特征及其对土壤磷盈亏(磷平衡)的响应,为南方双季稻区红壤性水稻土科学施磷提供依据。以35年长期肥料定位试验为平台,研究不同施肥处理土壤全磷、有效磷及磷活化系数(PAC)的演变规律,计算不同处理土壤-作物系统每年磷素盈亏量及累积磷素盈亏量,探讨土壤全磷、有效磷及PAC与累积磷盈亏量的响应关系。结果表明,不施磷肥的CK和NK处理土壤全磷、有效磷和PAC随试验年限呈持平或下降趋势;不施磷肥仅施猪粪的NK+PM处理土壤全磷呈缓慢上升趋势,有效磷和PAC呈下降趋势;施化学磷肥或化学磷肥配施稻草的NP、NPK、NP+RS和NPK+RS处理土壤全磷在试验前10年上升速率较快,之后25年上升速率变缓或随时间变化不显著,土壤有效磷在试验前5年急剧升高,之后随时间变化速率减缓或基本持平。CK、NK和NK+PM处理35年土壤PAC平均值较试验初始值分别下降33.2%、29.7%和16.6%,NP、NPK、NP+RS和NPK+RS土壤PAC较初始值分别提高66.2%、60.6%、65.6%和52.9%。不施磷肥导致红壤性水稻土磷素亏缺,不施化学磷肥仅施猪粪土壤磷素基本持平,施用化肥磷及化肥磷配施稻草土壤磷素盈余。土壤全磷、有效磷及PAC与土壤磷累积盈亏量均呈极显著正相关关系,土壤每盈余磷100 kg hm-2,全磷含量提高0.03 g kg-1,有效磷提高1.20 mg kg-1,土壤PAC上升0.09%。外源磷投入是影响土壤磷素及磷有效性的重要因素,在本试验条件下,长期不施磷或磷投入不足导致土壤磷亏缺,进而导致土壤磷及磷有效性降低,而化肥磷及有机无机磷配施促进了土壤磷盈余及土壤磷素肥力的提高。展开更多
文摘This study aimed to explore the effect of different proportions of organic fertilizer replacing chemical fertilizer on the bacterial community and metabolic function in paddy fields.The 16S rRNA absolute quantitative sequencing method was employed to study the response characteristics of soil bacterial community composition and species absolute abundance to environmental factors under three fertilization treatments[chemical fertilizer(NPK),organic fertilizer replacing 30%of chemical fertilizer(30M,estimated in terms of pure nitrogen,same below),and organic fertilizer replacing 60%of chemical fertilizer(60M)]for two consecutive years.Furthermore,the changes of bacterial metabolic functions of different fertilization treatments were predicted by PICRUSt2.The results showed that replacing chemical fertilizer with organic fertilizer at different proportions significantly increased the total nitrogen(TN),total potassium(TK),hydrolyzable nitrogen(HN),soil organic carbon(SOC),and significantly decreased the soil bulk density(SBD).Moreover,60M demonstrated better performance than 30M.Different fertilization treatments did not cause significant difference in soil bacterial richness index(Chao1)or diversity index(Shannon)but significantly affected bacterial community composition and species abundance.Particularly,60M significantly increased the abundance of 227 species,and it increased the total bacterial abundance by 25.30%and 56.58%compared with NPK and 30M,respectively.Redundancy analysis and Spearman correlation analysis revealed that SOC,TN,and AK were the key factors for shaping specific bacterial community structures under different fertilization treatments.The 60M treatment significantly increased the abundance of bacterial species involved in xenobiotic biodegradation and metabolism,amino acid metabolism,and lipid metabolism,thus improving the metabolic functions of soil microorganisms.
基金funded by the Special Fund for AgroScientific Research in the Public Interest of China (20110300508, 201203030)supported in partial by the Key Technologies R&D Program of China during the 12th Five-Year Plan period (2012BAD05B05-3, 2013BAD07B11)the International Plant Nutrition Institute, Canada (IPNI China Program: Hunan-17)
文摘In agricultural systems, maintenance of soil organic matter has long been recognized as a strategy to reduce soil degradation. Manure amendments and green manures are management practices that can increase some nutrient contents and improve soil aggregation. We investigated the effects of 28 yr of winter planted green manure on soil aggregate-size distribution and aggregateassociated carbon（C） and nitrogen（N）. The study was a randomized completed block design with three replicates. The treatments included rice-rice-fallow, rice-rice-rape, rice-rice-Chinese milk vetch and rice-rice-ryegrass. The experiment was established in 1982 on a silty light clayey paddy soil derived from Quaternary red clay（classified as Fe-Accumuli-Stagnic Anthrosols） with continuous early and late rice. In 2009, soil samples were collected（0-15 cm depth） from the field treatment plots and separated into water-stable aggregates of different sizes（i.e., 〉5, 2-5, 1-2, 0.5-1, 0.25-0.5 and 〈0.25 mm） by wet sieving. The long-term winter planted green manure significantly increased total C and N, and the formation of the 2-5-mm water-stable aggregate fraction. Compared with rice-rice-rape, rice-rice-Chinese milk vetch and rice-rice-ryegrass, the rice-rice-fallow significantly reduced 2-5-mm water-stable aggregates, with a significant redistribution of aggregates into micro-aggregates. Long-term winter planted green manure obviously improved C/N ratio and macro-aggregate-associated C and N. The highest contribution to soil fertility was from macro-aggregates of 2-5 mm in most cases.
基金supported by Special Fund for Agro-scientific Research in the Public Interest(201103005)Ministry of Agriculture,China and the International Plant Nutrition Institute(IPNI,Hunan-14)
文摘Soil physical properties are important indicators of the potential for agricultural production.Our objective was to evaluate the effects of long-term inputs of green manures on physical properties of a reddish paddy soil（Fe-Typic Hapli-Stagnic Anthrosols） under a double cropping system.The common cropping pattern before the study was early-late rice-fallow（winter）.The field treatments included rice-rice-fallow（R-R-WF）,rice-rice-rape（R-R-RP）,rice-rice-Chinese milk vetch（RR-MV）,and rice-rice-ryegrass（R-R-RG）.The rape,Chinese milk vetch and ryegrass were all incorporated as green manures 15 d before early rice transplanting during the following year.The soil bulk density in all green manure treatments was significantly reduced compared with the winter fallow treatment.Soil porosity with green manure applications was significantly higher than that under the winter fallow.The green manure treatments had higher 0.25-5 mm water stable aggregates and aggregates stabilities in the plow layer（0-15 cm depth） compared with the fallow treatment.The mean weight diameter（MWD） and normalized mean weight diameter（NMWD） of aggregates in the green manure treatment were larger than that with the winter fallow.Soil given green manure retained both a higher water holding capacity in the plow layer soil,and a larger volume of moisture at all matric potentials（-10,-33 and-100 kPa）.We conclude that the management of double-rice fields in southern central China should be encouraged to use green manures along with chemical fertilizers to increase SOC content,improve soil physical properties and soil fertility.
基金funded by the the Public Service Sectors (Agriculture) Research Special Funds, China(201203013-06)supported in partial by the International Plant Nutrition Institute (IPNI ChinaProgram: Hunan-16)the Key Technologies R&D Program of China during the 12th Five-Year-Plan period(2012BAD05B05-3)
文摘Increasing K＋ adsorption can be an effective alternative in building an available K pool in soils to optimize crop recovery and minimize losses into the environment. We hypothesized that long-term fertilization might change K＋ adsorption because of changes in the chemical and mineralogical properties of a rice （Oryza sativa L.）. The aims of this study were （i） to determine clay minerals in paddy soil clay size fractions using X-ray diffraction methods and a numerical diagramdecomposition method; （ii） to measure K＋ adsorption isotherms before and after H202 oxidation of organic matter, and （iii） to investigate whether K＋ adsorption is correlated with changes in soil chemical and mineral properties. The 30-yr longterm fertilization treatments caused little change in soil organic C （SOC） but a large variation in soil mineral composition. The whole-clay fraction （〈5 Jam） corresponded more to the fertilization treatment than the fine-clay fraction （〈1 gin） in terms of percentage of illite peak area. The total percentage of vermiculite-chlorite peak area was significantly negatively correlated with the total percentage ofillite peak area in the 〈5 lam soil particles （R=-0.946, P〈0.0006）. Different fertilization treatments gave significantly different results in K＋ adsorption. The SOC oxidation test showed positive effects of SOC on K＋ adsorption at lower K＋ concentration （≤120 mg L-0 and negative effects at higher K＋ concentration （240 mg L-l）. The K＋ adsorption by soil clay minerals after SOC oxidization accounted for 60-158% of that by unoxidized soils, suggesting a more important role of soil minerals than SOC on K＋ adsorption. The K＋ adsorption potential was significantly correlated to the amount of poorly crystallized illite present （R--0.879, P=0.012）. The availability of adsorbed K＋ for plant growth needs further study.
基金supported by the National High Technology Research and Development Program of China(863 Program)(2006AA10A401)
文摘Turbot(Scophthalmus maximus L.) reddish body iridovirus(TRBIV) was propagated in turbot fin cells(TF cells) and inactivated as the TRBIV vaccine with its protection efficiency evaluated in this study.TF cells were cultured in 10% bovine calf serum(BCS)-containing MEM medium(pH7.0) at 22℃,in which TRBIV propagated to a titer as high as 105.6 TCID50 mL-1.The TRBIV was inactivated with 0.1% formalin and formulated with 0.5% aluminum hydroxide.The inactivated vaccine caused neither cytopathogenic effect(CPE) on TF cells nor pathogenic effect on turbots.After being administered with the vaccine twice via muscle injection,the turbot developed high-tittered TRBIV neutralizing antibodies in a dose-dependent manner.The vaccine protected the turbot from dying with an immunoprotection rate of 83.3% as was determined via subcutaneous vaccination in the laboratory and 90.5% via bath vaccination in turbot farms,respectively.The inactivated vaccine was very immunogenic,efficiently preventing tur-bot from death.It holds the potential of being applied in aquaculture.
文摘Environmental magnetic research on beaches and shoreline processes is limited.Therefore,we carried out environmental magnetic studies on the heavy mineral-enriched,dark-reddish sands on Cedar Beach of western Lake Erie(41.68°N,82.40°W).Magnetite has been identified as the dominant magnetic mineral of these sands.This study reveals a spatial variation in concentration of magnetite particles,distribution of
基金Authors thanks the Universitat Jaume I[UJI-B2019-41]the Ministerio de Economía,Industria y Competitividad[MAT2016-80410-P]for financial support.
文摘Environment-friendly pigments based on AFeO_(3)(A=La,Pr,Nd,Sm,Gd,Tb,Y or Yb)with high nearinfrared(NIR)reflectance were synthesised by a coprecipitation method at 1200℃.The Rietveld refinement analysis showed single-phase orthorhombic perovskite for all compositions.All pigments,which showed reddish hues,offered good colour stability after mixing these pigments in powder form with siloxane transparent paint and two different glazes.The powderepaint mixtures produced with GdFeO_(3),TbFeO_(3) and YFeO_(3) pigments have the highest NIR solar reflectance,reaching values of R=50%.The temperature shielding studies conducted using TbFeO_(3) pigmentepaint mixture for a roof coating yielded a reduction of 3.2℃ in comparison to a commercial pigment.Moreover,the glazes that were pigmented using GdFeO_(3),TbFeO_(3) and YFeO_(3) compositions also presented the most intense reddish colours.A study of the thermal and chemical stability of the pigment with the highest NIR solar reflectance showed good stability in both cases.The reddish pigments that were prepared can therefore be good candidates for use in different applications such as cool pigments or pigments for ceramic glazes at high temperatures.
文摘研究双季稻种植制度下长期不同施肥红壤性水稻土磷素含量及磷素有效性演变特征及其对土壤磷盈亏(磷平衡)的响应,为南方双季稻区红壤性水稻土科学施磷提供依据。以35年长期肥料定位试验为平台,研究不同施肥处理土壤全磷、有效磷及磷活化系数(PAC)的演变规律,计算不同处理土壤-作物系统每年磷素盈亏量及累积磷素盈亏量,探讨土壤全磷、有效磷及PAC与累积磷盈亏量的响应关系。结果表明,不施磷肥的CK和NK处理土壤全磷、有效磷和PAC随试验年限呈持平或下降趋势;不施磷肥仅施猪粪的NK+PM处理土壤全磷呈缓慢上升趋势,有效磷和PAC呈下降趋势;施化学磷肥或化学磷肥配施稻草的NP、NPK、NP+RS和NPK+RS处理土壤全磷在试验前10年上升速率较快,之后25年上升速率变缓或随时间变化不显著,土壤有效磷在试验前5年急剧升高,之后随时间变化速率减缓或基本持平。CK、NK和NK+PM处理35年土壤PAC平均值较试验初始值分别下降33.2%、29.7%和16.6%,NP、NPK、NP+RS和NPK+RS土壤PAC较初始值分别提高66.2%、60.6%、65.6%和52.9%。不施磷肥导致红壤性水稻土磷素亏缺,不施化学磷肥仅施猪粪土壤磷素基本持平,施用化肥磷及化肥磷配施稻草土壤磷素盈余。土壤全磷、有效磷及PAC与土壤磷累积盈亏量均呈极显著正相关关系,土壤每盈余磷100 kg hm-2,全磷含量提高0.03 g kg-1,有效磷提高1.20 mg kg-1,土壤PAC上升0.09%。外源磷投入是影响土壤磷素及磷有效性的重要因素,在本试验条件下,长期不施磷或磷投入不足导致土壤磷亏缺,进而导致土壤磷及磷有效性降低,而化肥磷及有机无机磷配施促进了土壤磷盈余及土壤磷素肥力的提高。
