Certain agricultural management practices are known to affect the soil microbial community structure;however,knowledge of the response of the fungal community structure to the long-term continuous cropping and rotatio...Certain agricultural management practices are known to affect the soil microbial community structure;however,knowledge of the response of the fungal community structure to the long-term continuous cropping and rotation of soybean,maize and wheat in the same agroecosystem is limited.We assessed the fungal abundance,composition and diversity among soybean rotation,maize rotation and wheat rotation systems and among long-term continuous cropping systems of soybean,maize and wheat as the effect of crop types on fungal community structure.We compared these fungal parameters of same crop between long-term crop rotation and continuous cropping systems as the effect of cropping systems on fungal community structure.The fungal abundance and composition were measured by quantitative real-time PCR and Illumina MiSeq sequencing.The results revealed that long-term continuous soybean cropping increased the soil fungal abundance compared with soybean rotation,and the fungal abundance was decreased in long-term continuous maize cropping compared with maize rotation.The long-term continuous soybean cropping also exhibited increased soil fungal diversity.The variation in the fungal community structure among the three crops was greater than that between long-term continuous cropping and rotation cropping.Mortierella,Guehomyces and Alternaria were the most important contributors to the dissimilarity of the fungal communities between the continuous cropping and rotation cropping of soybean,maize and wheat.There were 11 potential pathogen and 11 potential biocontrol fungi identified,and the relative abundance of most of the potential pathogenic fungi increased during the long-term continuous cropping of all three crops.The relative abundance of most biocontrol fungi increased in long-term continuous soybean cropping but decreased in long-term continuous maize and wheat cropping.Our results indicate that the response of the soil fungal community structure to long-term continuous cropping varies based upon crop types.展开更多
Four soils, phaeozem (PM), saline-alkali soil (SA), meadow albic bleached soil (MA) and dark brown forest soil (DB) from Northeast China were used to examine the sorption and desorption characteristics of Cd and pH in...Four soils, phaeozem (PM), saline-alkali soil (SA), meadow albic bleached soil (MA) and dark brown forest soil (DB) from Northeast China were used to examine the sorption and desorption characteristics of Cd and pH influence on it. According to sorption experiment without pH control, the order of amount of absorbed Cd by soils was: SA>PM>DB>MA. The results from non-linear fitting method showed that Langmuir and Freundrich models were more adaptable than Temkin model in describing the sorption data. The maximum sorption amounts from Langmuir model were: PM>SA>MA>DB. Exponential equation for PM and SA and quadratic equation for MA and DB were suitable to fit the desorption data. The order of average desorption percentage was: MA>DB>PM>SA. The amounts of sorption by PM, DB and MA reached the maximum in pH 9.0, while sorption by SA was linearly increased in the experimental range of pH 3.3-11.4. In uniform pH, however, Cd sorption by SA was the minimum among four soils, which indicated that the more amounts of Cd absorbed by SA in isotherm sorption were ascribed to the higher soil pH. The higher sorption of Cd in PM resulted from the higher percentage of organic matter and clay components.展开更多
We study the electromagnetic coupling mechanism of a T1_(2)Ba_(2)CaCu_(2)O_(8)(TI-2212)thin film intrinsic Josephson junction to a hemispherical Fabry-Perot resonator.An effective model to analyze coupling mechanism i...We study the electromagnetic coupling mechanism of a T1_(2)Ba_(2)CaCu_(2)O_(8)(TI-2212)thin film intrinsic Josephson junction to a hemispherical Fabry-Perot resonator.An effective model to analyze coupling mechanism is put forward.The dielectric substrate is used as a dielectric resonator antenna and the Josephson junction,and a superconducting film is used as the feed line to excite a resonance mode inside the dielectric resonator antenna.To confirm this method,two Josephson junction samples with different dimensions of substrate and shapes of superconducting film are fabricated and tested under microwave irradiations.At the same time,numerical simulations of the antenna characteristics and the field distribution of these samples are performed by numerical simulation.The different coupling intensities of the two samples with the Fabry Perot resonator fit well with the numerical simulation results.The proposed model is important for Josephson junctions used in the microwave field.展开更多
基金funded by the National Key Research and Development Program of China(2016YFD02003009-6 and 2016YFD0300806)the National Natural Science Foundation of China(41771327 and 41571219)the earmarked fund for China Agriculture Research System(CARS04)
文摘Certain agricultural management practices are known to affect the soil microbial community structure;however,knowledge of the response of the fungal community structure to the long-term continuous cropping and rotation of soybean,maize and wheat in the same agroecosystem is limited.We assessed the fungal abundance,composition and diversity among soybean rotation,maize rotation and wheat rotation systems and among long-term continuous cropping systems of soybean,maize and wheat as the effect of crop types on fungal community structure.We compared these fungal parameters of same crop between long-term crop rotation and continuous cropping systems as the effect of cropping systems on fungal community structure.The fungal abundance and composition were measured by quantitative real-time PCR and Illumina MiSeq sequencing.The results revealed that long-term continuous soybean cropping increased the soil fungal abundance compared with soybean rotation,and the fungal abundance was decreased in long-term continuous maize cropping compared with maize rotation.The long-term continuous soybean cropping also exhibited increased soil fungal diversity.The variation in the fungal community structure among the three crops was greater than that between long-term continuous cropping and rotation cropping.Mortierella,Guehomyces and Alternaria were the most important contributors to the dissimilarity of the fungal communities between the continuous cropping and rotation cropping of soybean,maize and wheat.There were 11 potential pathogen and 11 potential biocontrol fungi identified,and the relative abundance of most of the potential pathogenic fungi increased during the long-term continuous cropping of all three crops.The relative abundance of most biocontrol fungi increased in long-term continuous soybean cropping but decreased in long-term continuous maize and wheat cropping.Our results indicate that the response of the soil fungal community structure to long-term continuous cropping varies based upon crop types.
基金Under the auspices of the K ey Projectof K now ledge Innovation Program of C hinese A cadem y of Sciences (N o.K ZC X 1-SW -19)
文摘Four soils, phaeozem (PM), saline-alkali soil (SA), meadow albic bleached soil (MA) and dark brown forest soil (DB) from Northeast China were used to examine the sorption and desorption characteristics of Cd and pH influence on it. According to sorption experiment without pH control, the order of amount of absorbed Cd by soils was: SA>PM>DB>MA. The results from non-linear fitting method showed that Langmuir and Freundrich models were more adaptable than Temkin model in describing the sorption data. The maximum sorption amounts from Langmuir model were: PM>SA>MA>DB. Exponential equation for PM and SA and quadratic equation for MA and DB were suitable to fit the desorption data. The order of average desorption percentage was: MA>DB>PM>SA. The amounts of sorption by PM, DB and MA reached the maximum in pH 9.0, while sorption by SA was linearly increased in the experimental range of pH 3.3-11.4. In uniform pH, however, Cd sorption by SA was the minimum among four soils, which indicated that the more amounts of Cd absorbed by SA in isotherm sorption were ascribed to the higher soil pH. The higher sorption of Cd in PM resulted from the higher percentage of organic matter and clay components.
基金Supported in part by the National High Technology Research and Development Program of China under Grant No 2009AA03Z208and the National Natural Science Foundation of China under Grant No 51002081.
文摘We study the electromagnetic coupling mechanism of a T1_(2)Ba_(2)CaCu_(2)O_(8)(TI-2212)thin film intrinsic Josephson junction to a hemispherical Fabry-Perot resonator.An effective model to analyze coupling mechanism is put forward.The dielectric substrate is used as a dielectric resonator antenna and the Josephson junction,and a superconducting film is used as the feed line to excite a resonance mode inside the dielectric resonator antenna.To confirm this method,two Josephson junction samples with different dimensions of substrate and shapes of superconducting film are fabricated and tested under microwave irradiations.At the same time,numerical simulations of the antenna characteristics and the field distribution of these samples are performed by numerical simulation.The different coupling intensities of the two samples with the Fabry Perot resonator fit well with the numerical simulation results.The proposed model is important for Josephson junctions used in the microwave field.