[Objective] The aim was to reveal the effects of different land use types on soil composition. [Method] GPRS,soil organic carbon content and soil texture in 3 depths (0-10,10-20,20-50 cm) of 5 main kind of selected la...[Objective] The aim was to reveal the effects of different land use types on soil composition. [Method] GPRS,soil organic carbon content and soil texture in 3 depths (0-10,10-20,20-50 cm) of 5 main kind of selected land use type were examined in Hainan. [Result] The results showed that GRSP and SOC content of four artificial land use types decreased compared with the natural secondary forest land,the GRSP content of all samples ranged from 0.53-4.80 mg/g,accounting for 7.9%-23.4% of the SOC,which means that GRSP was one important component of SOC pool in soil. The ratio of GRSP to SOC was significantly different among land use types but the depths. GRSP and SOC exhibited obvious vertical distribution pattern. GRSP was significantly positively related to SOC and sand content but negatively related to silt and clay content. [Conclusion] The sand content determined the GRSP content significantly and loam was better matrix for GRSP accumulation than clay.展开更多
A long-term experiment was conducted to investigate how long-term fertilization and rice straw incorporation into soil affect soil glomalin, C and N. The combined application of chemical fertilizer and straw resulted ...A long-term experiment was conducted to investigate how long-term fertilization and rice straw incorporation into soil affect soil glomalin, C and N. The combined application of chemical fertilizer and straw resulted in a significant increase in both soil easily extractable glomalin (EEG) and total glomalin (TG) concentrations, as compared with application of only chemical fertilizer or no fertilizer application. The EEG and TG concentrations of the NPKS (nitrogen, phosphorus, and potassium fertilizer application + rice straw return) plot were 4.68% and 5.67% higher than those of the CK (unfertilized control) plot, and 9.87% and 6.23% higher than those of the NPK (nitrogen, phosphorus, and potassium fertilizer applied annually) plot, respectively. Application of only chemical fertilizer did not cause a statistically significant change of soil glomalin compared with no fertilizer application. The changes of soil organic C (SOC) and total N (TN) contents demonstrated a similar trend to soil glomalin in these plots. The SOC and TN contents of NPKS plot were 15.01% and 9.18% higher than those of the CK plot, and 8.85% and 14.76% higher than those of the NPK plot, respectively. Rice straw return also enhanced the contents of microbial biomass C (MBC) and microbial biomass N (MBN) in the NPKS plot by 7.76% for MBC and 31.42% for MBN compared with the CK plot, and 12.66% for MBC and 15.07% for MBN compared with the NPK plots, respectively. Application of only chemical fertilizer, however, increased MBN concentration, but decreased MBC concentration in soil.展开更多
We present results on the effect of modified clay on cyst formation of Scrippsiella trochoidea in harmful algal bloom （HAB）. Modified clay （in concentration of 0, 0.1, 0.5, and 1.0 g/L） were added to cultures, and...We present results on the effect of modified clay on cyst formation of Scrippsiella trochoidea in harmful algal bloom （HAB）. Modified clay （in concentration of 0, 0.1, 0.5, and 1.0 g/L） were added to cultures, and observations were made on cysts of S. trochoidea under controlled laboratory conditions. Results indicate that the removal rate of algal cells reached 97.7% at the clay concentration of 1.0 g/L. The cyst formation rate increased from 4.6% to 24.6% when the concentration of clay was increased from 0 to 1.0 g/L. Two cyst metamorphs were observed： spinal calcareous cysts and smooth noncalcareous ones. The proportion of the spinal cysts decreased from 76.9% to 24.1% when clay concentration increased from 0 to 1.0 g/L. In addition, modified clay affected cyst germination. The germination rate decreased with the increases in the clay concentrations. Non-calcareous cysts had a lower germination rate with a longer germination time. We conclude that modified clay could depress algal cell multiplication and promote formation of temporal cysts of S. trochoidea, which may help in controlling HAB outbreaks.展开更多
In this study, the microbial quality of treated wastewater used for irrigation of three public parks in Dubai was evaluated. A total of 23 samples of TWW （treated wastewater） and 12 samples of irrigated soils from t...In this study, the microbial quality of treated wastewater used for irrigation of three public parks in Dubai was evaluated. A total of 23 samples of TWW （treated wastewater） and 12 samples of irrigated soils from three public parks were collected and tested for Legionella, Salmonella, traditional bacterial indicators, Cryptosporidium oocyst and Giardia cysts using membrane filtration and direct immune-fluorescence assay. The majority of the tested water samples were found contaminated with LLO （Legionella like organisms）, Salmonella and traditional bacterial indicators. Both Cryptosporidium oocysts and Giardia cysts were detected in these samples with a higher occurrence ofCryptosporidium oocysts （96%） than Giardia cysts （35%）. The fecal coliform bacteria were detected in 60.8% of water samples and 58% of soil samples. Total coliform bacteria were detected in most of the water and soil samples with a higher occurrence than the fecal coliform bacteria. The results of this study indicate that microorganisms are surviving the chlorination method used for disinfecting wastewater, and are further multiplying in the public parks irrigation network system. Therefore, monitoring the treated wastewater for bacterial pathogens, protozoan parasites and controlling their growth at the point of end use are vital to reducing the risk of environmental contamination with microbial pathogens.展开更多
A pot experiment was performed to determine the effects of arbuscular mycorrhizM fungi （AMF） communities on soil properties and the growth of cucumber seedlings in a degraded soil that had been used for continuous c...A pot experiment was performed to determine the effects of arbuscular mycorrhizM fungi （AMF） communities on soil properties and the growth of cucumber seedlings in a degraded soil that had been used for continuous cucumber monoculture in a greenhouse for 15 years. In the experiment, AMF communities （created by combining various AMF species that were found to be dominant in natural farm soil） were inoculated into the degraded soil, and then the soil was planted with cucumber. Inoculation with AMF communities did not affect soil pH but increased soil aggregate stability and decreased the concentrations of salt ions and electrical conductivity （EC） in the soil. Inoculation with AMF communities increased the numbers of culturable bacteria and actinomycetes but reduced the number of fungi. AMF communities increased plant growth, soluble sugar content, chlorophyll content, and root activity compared to non-mycorrhizal or a single AMF species treatments. Improvements of soil quality and plant growth were greatest with the following two communities： Glomus etunicatum ＋ G. mosseae ＋ Gigaspora margarita ＋ Acaulospora lacunosa and G. aggregatum ＋ G. etunicatum ＋ G. mosseae ＋ G. versiforme ＋ G. margarita ＋ A. lacunosa. The results suggested that certain AMF communities could substantially improve the quality of degraded soil.展开更多
基金Supported by National Natural Science Foundation of China(40761024)~~
文摘[Objective] The aim was to reveal the effects of different land use types on soil composition. [Method] GPRS,soil organic carbon content and soil texture in 3 depths (0-10,10-20,20-50 cm) of 5 main kind of selected land use type were examined in Hainan. [Result] The results showed that GRSP and SOC content of four artificial land use types decreased compared with the natural secondary forest land,the GRSP content of all samples ranged from 0.53-4.80 mg/g,accounting for 7.9%-23.4% of the SOC,which means that GRSP was one important component of SOC pool in soil. The ratio of GRSP to SOC was significantly different among land use types but the depths. GRSP and SOC exhibited obvious vertical distribution pattern. GRSP was significantly positively related to SOC and sand content but negatively related to silt and clay content. [Conclusion] The sand content determined the GRSP content significantly and loam was better matrix for GRSP accumulation than clay.
基金Project supported by the National Key Basic Research Support Foundation of China (No.2002CB410810).
文摘A long-term experiment was conducted to investigate how long-term fertilization and rice straw incorporation into soil affect soil glomalin, C and N. The combined application of chemical fertilizer and straw resulted in a significant increase in both soil easily extractable glomalin (EEG) and total glomalin (TG) concentrations, as compared with application of only chemical fertilizer or no fertilizer application. The EEG and TG concentrations of the NPKS (nitrogen, phosphorus, and potassium fertilizer application + rice straw return) plot were 4.68% and 5.67% higher than those of the CK (unfertilized control) plot, and 9.87% and 6.23% higher than those of the NPK (nitrogen, phosphorus, and potassium fertilizer applied annually) plot, respectively. Application of only chemical fertilizer did not cause a statistically significant change of soil glomalin compared with no fertilizer application. The changes of soil organic C (SOC) and total N (TN) contents demonstrated a similar trend to soil glomalin in these plots. The SOC and TN contents of NPKS plot were 15.01% and 9.18% higher than those of the CK plot, and 8.85% and 14.76% higher than those of the NPK plot, respectively. Rice straw return also enhanced the contents of microbial biomass C (MBC) and microbial biomass N (MBN) in the NPKS plot by 7.76% for MBC and 31.42% for MBN compared with the CK plot, and 12.66% for MBC and 15.07% for MBN compared with the NPK plots, respectively. Application of only chemical fertilizer, however, increased MBN concentration, but decreased MBC concentration in soil.
基金Supported by the National Natural Science Foundation of China(No.41276115)the Fund for Creative Research Groups by NSFC(No.41121064)the National Basic Research Program of China(973 Program)(No.2010CB428706)
文摘We present results on the effect of modified clay on cyst formation of Scrippsiella trochoidea in harmful algal bloom （HAB）. Modified clay （in concentration of 0, 0.1, 0.5, and 1.0 g/L） were added to cultures, and observations were made on cysts of S. trochoidea under controlled laboratory conditions. Results indicate that the removal rate of algal cells reached 97.7% at the clay concentration of 1.0 g/L. The cyst formation rate increased from 4.6% to 24.6% when the concentration of clay was increased from 0 to 1.0 g/L. Two cyst metamorphs were observed： spinal calcareous cysts and smooth noncalcareous ones. The proportion of the spinal cysts decreased from 76.9% to 24.1% when clay concentration increased from 0 to 1.0 g/L. In addition, modified clay affected cyst germination. The germination rate decreased with the increases in the clay concentrations. Non-calcareous cysts had a lower germination rate with a longer germination time. We conclude that modified clay could depress algal cell multiplication and promote formation of temporal cysts of S. trochoidea, which may help in controlling HAB outbreaks.
文摘In this study, the microbial quality of treated wastewater used for irrigation of three public parks in Dubai was evaluated. A total of 23 samples of TWW （treated wastewater） and 12 samples of irrigated soils from three public parks were collected and tested for Legionella, Salmonella, traditional bacterial indicators, Cryptosporidium oocyst and Giardia cysts using membrane filtration and direct immune-fluorescence assay. The majority of the tested water samples were found contaminated with LLO （Legionella like organisms）, Salmonella and traditional bacterial indicators. Both Cryptosporidium oocysts and Giardia cysts were detected in these samples with a higher occurrence ofCryptosporidium oocysts （96%） than Giardia cysts （35%）. The fecal coliform bacteria were detected in 60.8% of water samples and 58% of soil samples. Total coliform bacteria were detected in most of the water and soil samples with a higher occurrence than the fecal coliform bacteria. The results of this study indicate that microorganisms are surviving the chlorination method used for disinfecting wastewater, and are further multiplying in the public parks irrigation network system. Therefore, monitoring the treated wastewater for bacterial pathogens, protozoan parasites and controlling their growth at the point of end use are vital to reducing the risk of environmental contamination with microbial pathogens.
基金Supported by the National Natural Science Foundation of China (No. 30871737)the 2010 Open Foundation of State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences(No. Y052010038)
文摘A pot experiment was performed to determine the effects of arbuscular mycorrhizM fungi （AMF） communities on soil properties and the growth of cucumber seedlings in a degraded soil that had been used for continuous cucumber monoculture in a greenhouse for 15 years. In the experiment, AMF communities （created by combining various AMF species that were found to be dominant in natural farm soil） were inoculated into the degraded soil, and then the soil was planted with cucumber. Inoculation with AMF communities did not affect soil pH but increased soil aggregate stability and decreased the concentrations of salt ions and electrical conductivity （EC） in the soil. Inoculation with AMF communities increased the numbers of culturable bacteria and actinomycetes but reduced the number of fungi. AMF communities increased plant growth, soluble sugar content, chlorophyll content, and root activity compared to non-mycorrhizal or a single AMF species treatments. Improvements of soil quality and plant growth were greatest with the following two communities： Glomus etunicatum ＋ G. mosseae ＋ Gigaspora margarita ＋ Acaulospora lacunosa and G. aggregatum ＋ G. etunicatum ＋ G. mosseae ＋ G. versiforme ＋ G. margarita ＋ A. lacunosa. The results suggested that certain AMF communities could substantially improve the quality of degraded soil.
