Performances of belite-rich Portland cement, or HBC (high belite cement), and the resultant concrete are introduced by comparing with that of alite based PC (Portland cement) and concrete. The comparison study of ...Performances of belite-rich Portland cement, or HBC (high belite cement), and the resultant concrete are introduced by comparing with that of alite based PC (Portland cement) and concrete. The comparison study of cement properties indicates that HBC possesses the properties of less water demand for normal consistency, better compatibility with water reducer, higher later age strength after 28-day under standard curing temperature of 20 ℃, unique strength gain under elevated curing temperatures of 38-70 ℃, lower hydration heat evolution and temperature rise, lower drying shrinkage and excellent resistance to sulphate attack. These results have been demonstrated by the comparison performance evaluation of concretes prepared by HBC and PC in terms of workability, physical mechanical properties and durability when making high performance high strength concrete and massive concrete.展开更多
Monthly changes in sedimentation and sediment properties were studied for three different culture treatments: sea cucumber monoculture (Mc), sea cucumber and scallop polyculture (Ps-c) and scallop monoculture (M...Monthly changes in sedimentation and sediment properties were studied for three different culture treatments: sea cucumber monoculture (Mc), sea cucumber and scallop polyculture (Ps-c) and scallop monoculture (Ms). Results indicated that the survival rate of sea cucumber was significantly higher in Ps-c cultures than in Mc cultures. Sea cucumber yield was 69.6% higher in Ps-c culture than in Mc culture. No significant differences in body weight and scallop shell length were found between Ps-c and Ms cultures. The mean sedimentation rate of total particulate matter (TPM) was 72.2 g/(m^2.d) in Ps-c cultures, with a maximum of 119.7 g/(mE.d), which was markedly higher than that of Mc (mean value). Sedimentation rates of organic matter (OM), total organic carbon (TOC), total nitrogen (TN) and total phosphorus (TP) in Ps-c cultures were also significantly higher than those in Mc cultures. TOC and TN contents of sediment increased rapidly in the first 5 months in Ms cultures and remained at a high level. TOC and TN contents in Mc and Ps-c cultures decreased during sea cucumber feeding seasons and increased during sea cucumber dormancy periods (summer and winter). The study demonstrates that co-culture of sea cucumber and scallop in earthen ponds is an alternative way to alleviate nutrient loads and improve water quality in coastal aquaculture systems. Moreover, it provides the additional benefit of an increased sea cucumber yield.展开更多
Marsupenaeusjaponicus Bate is one of the most valuable cultured shrimp species in China and outdoor earthen pond farming is the most common method of culturing this organism. The need to increase soil usage efficiency...Marsupenaeusjaponicus Bate is one of the most valuable cultured shrimp species in China and outdoor earthen pond farming is the most common method of culturing this organism. The need to increase soil usage efficiency in aquaculture has been recognized and a great deal of research effort has been directed toward development of super-intensive farming systems. However, current research and development in this field is largely devoted to Litopenaeus vannamei Boone, while to M.japonicus Bate it has been neglected. In this study, a layered fanning system was designed and a 66-day study was conducted in M.japonicus Bate culture. The system comprised bracket and sand layers that divided a shrimp tank filled to a depth of 1.2 m into four water layers. Conventional tank culture (unlayered) was used as a control. The results show that survival rate, feed conversion efficiency and production of M.japonicus Bate in the layered farming system were 68%, 18%, and 0.59 kg/m^2, respectively, all of which are significantly higher than in the unlayered fanning system (P〈0.01). These findings confirmed the possibility of using a layered system to culture M. japonicus Bate.展开更多
This article presents two approaches for automated building of knowledge bases of soil resources mapping. These methods used decision tree and Bayesian predictive modeling, respectively to generate knowledge from tra...This article presents two approaches for automated building of knowledge bases of soil resources mapping. These methods used decision tree and Bayesian predictive modeling, respectively to generate knowledge from training data. With these methods, building a knowledge base for automated soil mapping is easier than using the conventional knowledge acquisition approach. The knowledge bases built by these two methods were used by the knowledge classifier for soil type classification of the Longyou area, Zhejiang Province, China using TM bi-temporal imageries and GIS data. To evaluate the performance of the resultant knowledge bases, the classification results were compared to existing soil map based on field survey. The accuracy assessment and analysis of the resultant soil maps suggested that the knowledge bases built by these two methods were of good quality for mapping distribution model of soil classes over the study area.展开更多
Numerous studies have focused on vegetation traits and soil properties in grassland, few of which concerned about effects of human utilization patterns on grassland yet. Thus, this study hypothesized that human distur...Numerous studies have focused on vegetation traits and soil properties in grassland, few of which concerned about effects of human utilization patterns on grassland yet. Thus, this study hypothesized that human disturbance(e.g., grazing, mowing and fencing) triggered significant variation of biomass partitioning and carbon reallocation. Besides, there existed some differences of species diversity and soil fertility. To address these hypotheses of grassland with diverse utilization patterns in Hulun Buir City, Inner Mongolia, China, we sampled in situ about aboveground biomass(AGB) and belowground biomass(BGB) to evaluate their biomass allocation. Species diversity and soil properties were also investigated. Subsequently, we discussed the relationship of species diversity with environmental conditions, using data collected from 23 sites during the ecological project period of Returning Grazing Lands to Grasslands(RGLG) program. The results were as follows: 1) both AGB and BGB were lower on grazing regime than those on fencing and mowing, but the ratio of root-to-shoot(R/S) was higher on grazing regime than the other two utilization patterns; 2) neither of evenness and Simpson Index was different significantly among all grassland utilization patterns in desert, typical, and meadow grassland at 0.05. In meadow grassland, species richness of fencing pattern was significantly higher than that of grazing pattern(p < 0.05); 3) both of soil organic carbon content and soil available phosphorous content were increased significantly on fencing pattern than grazing pattern(p < 0.05) in desert grassland, and mowing patterns increased the soil nutrients(soil organic carbon, soil total phosphorous, soil available phosphorous, and soil total nitrogen) significantly compared with grazing patterns(p < 0.05) in typical grassland. However, there were no significant differences among utilization patterns in meadow grassland. In conclusion, both of AGB and BGB were increased significantly by fencing. Moreover, species diversity and soil nutrients can be promoted via mowing and fencing. This study suggested that implementation of Ecological Project played a positive role in sustainable grassland utilization of Hulun Buir City and a strong positive influence on the entire temperate grassland.展开更多
In this study, the authors were interested to the evaluation of biodiversity in the Jebel Tessala. Ten stations were selected based on altitudinal gradient, inside each station, identified flora has been conducted and...In this study, the authors were interested to the evaluation of biodiversity in the Jebel Tessala. Ten stations were selected based on altitudinal gradient, inside each station, identified flora has been conducted and a soil sample was taken from. A floristic inventory was carried out from all stations characterizing habitat of our studied taxon which is Rhamnus alaternus L. The authors established a list of plants represented by 94 species, distributed in 46 botanical families that are dominated by Asteraceae. The biological spectrum of these species reveals the dominance of hemicryptophytes and therophytes. The biogeographical element which predominates the vegetation is the Mediterranean-type. Statistical processing PCA (principal component analysis) from the pedological analysis of the examined stations reveals the formation of three groups defining a set of station that are marked by the presence of some components of the soil. Data processing obtained by FCA (factorial correspondence analysis) and the ascending hierarchical classification had underscored the existence of two groups of strata according to the soil substrate.展开更多
Setting out from the categories of totality and histori(ci)sm in Kosik's Dialectics of the Concrete, we look at the relationship between theory and praxis: empty, abstract totality versus concrete, reified and ali...Setting out from the categories of totality and histori(ci)sm in Kosik's Dialectics of the Concrete, we look at the relationship between theory and praxis: empty, abstract totality versus concrete, reified and alienated practice (Lukacs, Habermas, Honneth); a bad totality, in which the real polydimensional subject is replaced by the one-dimensional, mythologized, fetishized, and economistically reduced "subject" of consummation (Marcuse, Baudrillard). The dialectics of concrete totality implies a marxistic critique of the ethical and juristic universalism, in the context of the "positive" side of globalization and political unilateralism, as a concrete, militant, hegemonistic, post-colonial, and neo-imperial practice (Apel, Habermas, Chomsky, Zinoviev); globalization as totali(tari)zation, the "last man," the "end of history," and the "end" of dialectics in its neo-liberal, eschatological, empty ideological "realization" (Hegel, Marx, Fukuyama, Arendt); the totality of the (invariable) being as a pseudo-concrete and pseudo-dialectical ontologistic speculation (Heidegger): A "return" to a concrete history and a return of the "positive" dialectics as a critical awareness, mind, and method in the discourse "game" of human's cognitive, creative, and practical powers. The assumption of Kosik's humanism is a synchrony of nature and history in the "absolute" totality of human's concrete existence (Lukacs, Goldmann, Adorno, Sartre, Kosik).展开更多
OBJECTIVE: To test the synergistic effects of the aqueous extract of Tubeimu (Rhizoma Bolbosternmatis) and Fuzi (Radix Aconiti Lateralis Preparata) on MDA-MB-231 and SKBR3 breast cancer cells.METHODS: A combined...OBJECTIVE: To test the synergistic effects of the aqueous extract of Tubeimu (Rhizoma Bolbosternmatis) and Fuzi (Radix Aconiti Lateralis Preparata) on MDA-MB-231 and SKBR3 breast cancer cells.METHODS: A combined index was created for the effects of Tubeimu (Rhizoma Bolbostemmatis) and Fuzi (Radix Aconiti Lateralis Preparata) extracts. Cell proliferation was performed by trypan blue exclusion and 3-(4,5-dimethylthiazol-2-yl)-5-(3- carboxy- methoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assays. Flow cytometry was used to assess cell cycle distribution and apoptosis. Cell migration was determined by wound-healing and transwell assays. Confocal microscopy was used to detect E-cadherin and actin filaments. RESULTS: The aqueous extract from Tubeimu (Rhizoma Bolbostemmatis)and Fuzi (Radix Aconiti lateralis Preparata) exerted synergetic effects on the growth of MDA-MB-231 cells and G1 phase arrest. When exposed to extracts at concentrations of 62.5 :62.5 and 62.5:31.3 μg/mL, the combination index was 0.83 and 0.74, respectively. Interestingly, 62.5: 31.3 μg/mL of combined drugs enhanced the inhibitory effect of Tubeimu (Rhizoma Bolbostemmatis) on the migration of SKBR3 cells and reduced the stimulative effect of Fuzi (Radix Aconiti Lateralis Preparata) (P 〈 0.01), in which cells showed an increased expression of E-cadherin and reorganization of actin filaments (P 〈 0.001). 62.5:62.5 μg/mL extract also synergistically induced apoptosis of MDA-MB-231 cells (P 〈 0.05 and P 〈 0.001). Acting as the main active ingredients in the extract, tubeimoside I and acetylbenzoylaconine at 10:10μg/ mL and 5:2.5 μg/mL also produced inhibitory effects on the proliferation and migration of cells (P 〈 0.01). CONCLUSION: Tubeimu (Rhizoma Bolbostemmatis) and Fuzi (Radix Aconiti Lateralis Preparata) extracts had synergic effects on MDA-MB-231 and SKBR3 cells.展开更多
Large quantities of mussel shells (66000-94000 t year^-1), an alkaline material that can be used as a soil amendment, are generated as waste in Galicia, NW Spain. A field trial was carried out by planting different ...Large quantities of mussel shells (66000-94000 t year^-1), an alkaline material that can be used as a soil amendment, are generated as waste in Galicia, NW Spain. A field trial was carried out by planting different pasture species in a Haplic Umbrisol using a randomized block design with four blocks and six treatments (not amended control or soil amended with lime, finely ground shell, coarsely ground shell, finely ground calcined shell or coarsely ground calcined shell) to compare the effects of lime and mussel shells additions on a soil with a low cation exchange capacity and high AI saturation. The trial was established in March 2007, and samples of plants and soil were collected when plots were harvested in summer 2008 (separating the bulk and rhizosphere soil). The soils were analyzed for pH, total C, total N, available P, exchangeable cations, effective cation exchange capacity and available micronutrients. Dry matter yield was measured in all plots and plants were analyzed for nutrients. Application of mussel shells and the commercial lime resulted in an increase in pH and exchangeable Ca and a decrease in exchangeable Al and Al were most noticeable in the rhizosphere. The amendment of Ca in the plant. saturation. The stability of pH over time was high. These effects also had a positive effect on dry matter yield and concentration展开更多
Cropping activities may affect soil microbial activities and biomass,which would affect C and N cycling in soil and thus the crop yields and quality.In the present study,a combination of microcalorimetric,enzyme activ...Cropping activities may affect soil microbial activities and biomass,which would affect C and N cycling in soil and thus the crop yields and quality.In the present study,a combination of microcalorimetric,enzyme activity(sucrase,urease,catalase,and fluorescein diacetate hydrolysis),and real-time polymerase chain reaction(RT-PCR) analyses was used to investigate microbial status of farmland soils,collected from 5 different sites in Huazhong Agriculture University,China.Our results showed that among the 5sites,both positive and negative impacts of cropping activities on soil microbial activity were observed.Enzyme activity analysis showed that cropping activities reduced soil sucrase and urease activities,which would influence the C and N cycles in soil.Much more attentions should be given to microbial status affected by cropping activities in future.According to the correlation analysis,fluorescein diacetate hydrolysis showed a significantly(P < 0.05) negative correlation with the time to reach the maximum power output(R ——0.898),but a significantly(P < 0.05) positive correlation with bacterial gene copy number(R = 0.817).Soil catalase activity also showed a significantly(P < 0.05) positive correlation with bacterial gene copy number(R = 0.965).Using combined methods would provide virtual information of soil microbial status.展开更多
文摘Performances of belite-rich Portland cement, or HBC (high belite cement), and the resultant concrete are introduced by comparing with that of alite based PC (Portland cement) and concrete. The comparison study of cement properties indicates that HBC possesses the properties of less water demand for normal consistency, better compatibility with water reducer, higher later age strength after 28-day under standard curing temperature of 20 ℃, unique strength gain under elevated curing temperatures of 38-70 ℃, lower hydration heat evolution and temperature rise, lower drying shrinkage and excellent resistance to sulphate attack. These results have been demonstrated by the comparison performance evaluation of concretes prepared by HBC and PC in terms of workability, physical mechanical properties and durability when making high performance high strength concrete and massive concrete.
基金Supported by the National Key Technology Research and Development Program of China (Nos. 2006BAD09A01, 200905020)the National Natural Science Foundation of China (No. 30871931)the Program for New Century Excellent Talents in University (No. NCET-08-0503)
文摘Monthly changes in sedimentation and sediment properties were studied for three different culture treatments: sea cucumber monoculture (Mc), sea cucumber and scallop polyculture (Ps-c) and scallop monoculture (Ms). Results indicated that the survival rate of sea cucumber was significantly higher in Ps-c cultures than in Mc cultures. Sea cucumber yield was 69.6% higher in Ps-c culture than in Mc culture. No significant differences in body weight and scallop shell length were found between Ps-c and Ms cultures. The mean sedimentation rate of total particulate matter (TPM) was 72.2 g/(m^2.d) in Ps-c cultures, with a maximum of 119.7 g/(mE.d), which was markedly higher than that of Mc (mean value). Sedimentation rates of organic matter (OM), total organic carbon (TOC), total nitrogen (TN) and total phosphorus (TP) in Ps-c cultures were also significantly higher than those in Mc cultures. TOC and TN contents of sediment increased rapidly in the first 5 months in Ms cultures and remained at a high level. TOC and TN contents in Mc and Ps-c cultures decreased during sea cucumber feeding seasons and increased during sea cucumber dormancy periods (summer and winter). The study demonstrates that co-culture of sea cucumber and scallop in earthen ponds is an alternative way to alleviate nutrient loads and improve water quality in coastal aquaculture systems. Moreover, it provides the additional benefit of an increased sea cucumber yield.
基金Supported by the Science and Technology Plan of Qingdao(No.103-4-5-6-jch)the National Natural Science Foundation of China(No.31101916)+1 种基金the Natural Science Foundation of Shandong Province,China(No.ZR2010CM060)the University Student Innovation Plan of Qingdao Agricultural University(No.201030)
文摘Marsupenaeusjaponicus Bate is one of the most valuable cultured shrimp species in China and outdoor earthen pond farming is the most common method of culturing this organism. The need to increase soil usage efficiency in aquaculture has been recognized and a great deal of research effort has been directed toward development of super-intensive farming systems. However, current research and development in this field is largely devoted to Litopenaeus vannamei Boone, while to M.japonicus Bate it has been neglected. In this study, a layered fanning system was designed and a 66-day study was conducted in M.japonicus Bate culture. The system comprised bracket and sand layers that divided a shrimp tank filled to a depth of 1.2 m into four water layers. Conventional tank culture (unlayered) was used as a control. The results show that survival rate, feed conversion efficiency and production of M.japonicus Bate in the layered farming system were 68%, 18%, and 0.59 kg/m^2, respectively, all of which are significantly higher than in the unlayered fanning system (P〈0.01). These findings confirmed the possibility of using a layered system to culture M. japonicus Bate.
基金Project supported by the National Natural Science Foundation ofChina (No. 40101014) and by the Science and technology Committee of Zhejiang Province (No. 001110445) China
文摘This article presents two approaches for automated building of knowledge bases of soil resources mapping. These methods used decision tree and Bayesian predictive modeling, respectively to generate knowledge from training data. With these methods, building a knowledge base for automated soil mapping is easier than using the conventional knowledge acquisition approach. The knowledge bases built by these two methods were used by the knowledge classifier for soil type classification of the Longyou area, Zhejiang Province, China using TM bi-temporal imageries and GIS data. To evaluate the performance of the resultant knowledge bases, the classification results were compared to existing soil map based on field survey. The accuracy assessment and analysis of the resultant soil maps suggested that the knowledge bases built by these two methods were of good quality for mapping distribution model of soil classes over the study area.
基金Under the auspices of Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA05060100)National Natural Science Foundation of China(No.41105117)
文摘Numerous studies have focused on vegetation traits and soil properties in grassland, few of which concerned about effects of human utilization patterns on grassland yet. Thus, this study hypothesized that human disturbance(e.g., grazing, mowing and fencing) triggered significant variation of biomass partitioning and carbon reallocation. Besides, there existed some differences of species diversity and soil fertility. To address these hypotheses of grassland with diverse utilization patterns in Hulun Buir City, Inner Mongolia, China, we sampled in situ about aboveground biomass(AGB) and belowground biomass(BGB) to evaluate their biomass allocation. Species diversity and soil properties were also investigated. Subsequently, we discussed the relationship of species diversity with environmental conditions, using data collected from 23 sites during the ecological project period of Returning Grazing Lands to Grasslands(RGLG) program. The results were as follows: 1) both AGB and BGB were lower on grazing regime than those on fencing and mowing, but the ratio of root-to-shoot(R/S) was higher on grazing regime than the other two utilization patterns; 2) neither of evenness and Simpson Index was different significantly among all grassland utilization patterns in desert, typical, and meadow grassland at 0.05. In meadow grassland, species richness of fencing pattern was significantly higher than that of grazing pattern(p < 0.05); 3) both of soil organic carbon content and soil available phosphorous content were increased significantly on fencing pattern than grazing pattern(p < 0.05) in desert grassland, and mowing patterns increased the soil nutrients(soil organic carbon, soil total phosphorous, soil available phosphorous, and soil total nitrogen) significantly compared with grazing patterns(p < 0.05) in typical grassland. However, there were no significant differences among utilization patterns in meadow grassland. In conclusion, both of AGB and BGB were increased significantly by fencing. Moreover, species diversity and soil nutrients can be promoted via mowing and fencing. This study suggested that implementation of Ecological Project played a positive role in sustainable grassland utilization of Hulun Buir City and a strong positive influence on the entire temperate grassland.
文摘In this study, the authors were interested to the evaluation of biodiversity in the Jebel Tessala. Ten stations were selected based on altitudinal gradient, inside each station, identified flora has been conducted and a soil sample was taken from. A floristic inventory was carried out from all stations characterizing habitat of our studied taxon which is Rhamnus alaternus L. The authors established a list of plants represented by 94 species, distributed in 46 botanical families that are dominated by Asteraceae. The biological spectrum of these species reveals the dominance of hemicryptophytes and therophytes. The biogeographical element which predominates the vegetation is the Mediterranean-type. Statistical processing PCA (principal component analysis) from the pedological analysis of the examined stations reveals the formation of three groups defining a set of station that are marked by the presence of some components of the soil. Data processing obtained by FCA (factorial correspondence analysis) and the ascending hierarchical classification had underscored the existence of two groups of strata according to the soil substrate.
文摘Setting out from the categories of totality and histori(ci)sm in Kosik's Dialectics of the Concrete, we look at the relationship between theory and praxis: empty, abstract totality versus concrete, reified and alienated practice (Lukacs, Habermas, Honneth); a bad totality, in which the real polydimensional subject is replaced by the one-dimensional, mythologized, fetishized, and economistically reduced "subject" of consummation (Marcuse, Baudrillard). The dialectics of concrete totality implies a marxistic critique of the ethical and juristic universalism, in the context of the "positive" side of globalization and political unilateralism, as a concrete, militant, hegemonistic, post-colonial, and neo-imperial practice (Apel, Habermas, Chomsky, Zinoviev); globalization as totali(tari)zation, the "last man," the "end of history," and the "end" of dialectics in its neo-liberal, eschatological, empty ideological "realization" (Hegel, Marx, Fukuyama, Arendt); the totality of the (invariable) being as a pseudo-concrete and pseudo-dialectical ontologistic speculation (Heidegger): A "return" to a concrete history and a return of the "positive" dialectics as a critical awareness, mind, and method in the discourse "game" of human's cognitive, creative, and practical powers. The assumption of Kosik's humanism is a synchrony of nature and history in the "absolute" totality of human's concrete existence (Lukacs, Goldmann, Adorno, Sartre, Kosik).
基金Supported by Funding Program of(National Science Foundation of China(Mechanism of Warming and Relieving Cold Phlegm Therapy Inhibiting Tumor Metastasis from the Field of Biomechanical,No.81503383)Science and Technology Development of Tianjin Municipal Higher Education(Compatibility Principle of Warming and Relieving Cold Phlegm Formula for the Treatment of Human Hepatocellular Carcinoma,No.20110105)Tianjin city application basis and cutting-edge technology research program(Effect of Herbs Formula Radix Aconiti Praeparata-Rhizoma Bolbostemmatis on Breast Cancer,No.13JCQNJC13800)
文摘OBJECTIVE: To test the synergistic effects of the aqueous extract of Tubeimu (Rhizoma Bolbosternmatis) and Fuzi (Radix Aconiti Lateralis Preparata) on MDA-MB-231 and SKBR3 breast cancer cells.METHODS: A combined index was created for the effects of Tubeimu (Rhizoma Bolbostemmatis) and Fuzi (Radix Aconiti Lateralis Preparata) extracts. Cell proliferation was performed by trypan blue exclusion and 3-(4,5-dimethylthiazol-2-yl)-5-(3- carboxy- methoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assays. Flow cytometry was used to assess cell cycle distribution and apoptosis. Cell migration was determined by wound-healing and transwell assays. Confocal microscopy was used to detect E-cadherin and actin filaments. RESULTS: The aqueous extract from Tubeimu (Rhizoma Bolbostemmatis)and Fuzi (Radix Aconiti lateralis Preparata) exerted synergetic effects on the growth of MDA-MB-231 cells and G1 phase arrest. When exposed to extracts at concentrations of 62.5 :62.5 and 62.5:31.3 μg/mL, the combination index was 0.83 and 0.74, respectively. Interestingly, 62.5: 31.3 μg/mL of combined drugs enhanced the inhibitory effect of Tubeimu (Rhizoma Bolbostemmatis) on the migration of SKBR3 cells and reduced the stimulative effect of Fuzi (Radix Aconiti Lateralis Preparata) (P 〈 0.01), in which cells showed an increased expression of E-cadherin and reorganization of actin filaments (P 〈 0.001). 62.5:62.5 μg/mL extract also synergistically induced apoptosis of MDA-MB-231 cells (P 〈 0.05 and P 〈 0.001). Acting as the main active ingredients in the extract, tubeimoside I and acetylbenzoylaconine at 10:10μg/ mL and 5:2.5 μg/mL also produced inhibitory effects on the proliferation and migration of cells (P 〈 0.01). CONCLUSION: Tubeimu (Rhizoma Bolbostemmatis) and Fuzi (Radix Aconiti Lateralis Preparata) extracts had synergic effects on MDA-MB-231 and SKBR3 cells.
基金Supported by the Government of Spain(No.CTM2005-05922)
文摘Large quantities of mussel shells (66000-94000 t year^-1), an alkaline material that can be used as a soil amendment, are generated as waste in Galicia, NW Spain. A field trial was carried out by planting different pasture species in a Haplic Umbrisol using a randomized block design with four blocks and six treatments (not amended control or soil amended with lime, finely ground shell, coarsely ground shell, finely ground calcined shell or coarsely ground calcined shell) to compare the effects of lime and mussel shells additions on a soil with a low cation exchange capacity and high AI saturation. The trial was established in March 2007, and samples of plants and soil were collected when plots were harvested in summer 2008 (separating the bulk and rhizosphere soil). The soils were analyzed for pH, total C, total N, available P, exchangeable cations, effective cation exchange capacity and available micronutrients. Dry matter yield was measured in all plots and plants were analyzed for nutrients. Application of mussel shells and the commercial lime resulted in an increase in pH and exchangeable Ca and a decrease in exchangeable Al and Al were most noticeable in the rhizosphere. The amendment of Ca in the plant. saturation. The stability of pH over time was high. These effects also had a positive effect on dry matter yield and concentration
基金supported by the Public Welfare Project of Ministry of Environmental Protection of China(Nos.201409042 and 201509049)the National Natural Science Foundation of China(Nos. 41430106,41273092,U1402234,and 41603083)
文摘Cropping activities may affect soil microbial activities and biomass,which would affect C and N cycling in soil and thus the crop yields and quality.In the present study,a combination of microcalorimetric,enzyme activity(sucrase,urease,catalase,and fluorescein diacetate hydrolysis),and real-time polymerase chain reaction(RT-PCR) analyses was used to investigate microbial status of farmland soils,collected from 5 different sites in Huazhong Agriculture University,China.Our results showed that among the 5sites,both positive and negative impacts of cropping activities on soil microbial activity were observed.Enzyme activity analysis showed that cropping activities reduced soil sucrase and urease activities,which would influence the C and N cycles in soil.Much more attentions should be given to microbial status affected by cropping activities in future.According to the correlation analysis,fluorescein diacetate hydrolysis showed a significantly(P < 0.05) negative correlation with the time to reach the maximum power output(R ——0.898),but a significantly(P < 0.05) positive correlation with bacterial gene copy number(R = 0.817).Soil catalase activity also showed a significantly(P < 0.05) positive correlation with bacterial gene copy number(R = 0.965).Using combined methods would provide virtual information of soil microbial status.