The study of Nitrogen fixation, uptake, and leaching at different soil depths in the co-cultivation of maize and soybean under phosphorus fertilization is important for sustainable agriculture. This study was conducte...The study of Nitrogen fixation, uptake, and leaching at different soil depths in the co-cultivation of maize and soybean under phosphorus fertilization is important for sustainable agriculture. This study was conducted in Quzhou, Hebei Province, China, with MC812 maize and Jidou12 soybean varieties. Soil samples were taken from each plot to create a composite sample. The results show that nitrogen concentration varies at different depths and is higher in all treatments between 40 and 100 cm. Incorporating intercropping of maize and soybeans into farming practices can lead to more sustainable and environmentally friendly agriculture in China.展开更多
Intercropping, particularly the combination of maize and soybeans, has been widely recognized for its potential to improve nitrogen uptake and promote sustainable agriculture. This study examines the patterns of nitro...Intercropping, particularly the combination of maize and soybeans, has been widely recognized for its potential to improve nitrogen uptake and promote sustainable agriculture. This study examines the patterns of nitrogen uptake in maize and soybean intercropping systems under different growth stages and phosphorus fertilization levels and investigates the influence of nitrogen uptake on growth parameters such as plant height, leaf area, and biomass accumulation in the maize/soybean intercrop under different phosphorus fertilization regimes. The study also collected chlorophyll samples at different growth stages of maize in monoculture and intercropping with maize or soybean. The results showed that plant height was greater in V10 in both fertilized and unfertilized treatments for intercropped maize and soybean, and chlorophyll concentration was higher in VT intercropped maize. The results also showed a higher accumulation of biomass. Understanding the growth dynamics of these plants in monoculture and intercropping systems and the impact of fertilization practices is crucial for optimizing crop productivity and sustainability in agricultural systems.展开更多
Three-River Headwaters （TRH） region involved in this paper refers to the source region of the Changjiang （Yangtze） River, the Huanghe （Yellow） River and the Lancang River in China. Taking the TRH region of the Q...Three-River Headwaters （TRH） region involved in this paper refers to the source region of the Changjiang （Yangtze） River, the Huanghe （Yellow） River and the Lancang River in China. Taking the TRH region of the Qing- hai-Tibet Plateau as a case, the annual evapotranspiration （ET） model developed by Zhang et al. （2001） was applied to evaluate mean annual ET in the alpine area, and the response of annual ET to land use change was analyzed. The plant-available water coefficient （w） of Zhang＇s model was revised by using vegetation-temperature condition index （VTCI） before annual ET was calculated in alpine area. The future land use scenario, an input of ET model, was spa- tially simulated by using the conversion of land use and its effects at small regional extent （CLUE-S） to study the re- sponse of ET to land use change. Results show that the relative errors between the simulated ET and that calculated by using water balance equation were 3.81% and the index of agreement was 0.69. This indicates that Zhang＇s ET model based on revised plant-available water coefficient is a scientific and practical tool to estimate the annual ET in the al- pine area. The annual ET in 2000 in the study area was 221.2 ram, 11.6 mm more than that in 1980. Average annual ET decreased from southeast to northwest, but the change of annual ET between 1980 and 2000 increased from southeast to northwest. As a vast and sparsely populated area, the population in the TRH region was extremely unbalanced and land use change was concentrated in very small regions. Thus, land use change had little effect on total annual ET in the study area but a great impact on its spatial distribution, and the effect of land use change on ET decreased with in- creasing precipitation. ET was most sensitive to the interconversion between forest and unused land, and was least sen- sitive to the interconversion between cropland and low-covered grassland.展开更多
The effect of sodium dodecylbenzenesulfonate (SDBS), an anionic surfactant used widely in household products and industrial processes, on saturated hydraulic conductivities (Ksat) of an Anthrosol saturated with sodium...The effect of sodium dodecylbenzenesulfonate (SDBS), an anionic surfactant used widely in household products and industrial processes, on saturated hydraulic conductivities (Ksat) of an Anthrosol saturated with sodium (Na-soil) or calcium (Ca-soil) was analyzed in a laboratory experiment using the constant head method, and adsorption and dispersion experiments were also conducted to infer the possible mechanisms of Ksat fluctuations. The results showed that SDBS was more intensely adsorbed in the Ca-soil than in the Na-soil. With an increase in the SDBS concentration, the stability of the Na-soil suspensions decreased when the SDBS concentration was less than 1.2 mmol L-1 and then above this concentration, increased markedly, while the stability of the Ca-soil suspensions increased gradually at all SDBS concentrations studied. With an increase in the SDBS concentration, the Ksat of the Na-soil increased, which resulted mainly from the increase of water channels in the soil because of the coagulation of the soil particles, while the Ksat of Ca-soil decreased mainly on account of the clogging of partial water channels by precipitated Ca(DBS)2 and the fine soil particles generated.展开更多
In semiarid areas, cereal crops often alocate more biomass to root at the expense of aboveground yield. A pot experiment was conducted to investigate carbon consumption of roots and its impact on grain yield of spring...In semiarid areas, cereal crops often alocate more biomass to root at the expense of aboveground yield. A pot experiment was conducted to investigate carbon consumption of roots and its impact on grain yield of spring wheat （Triticum aestivum L.） as affected by water and phosphorus （P） supply. A factorial design was used with six treatments namely two water regimes （at 80–75% and 50–45% ifeld capacity （FC）） and three P supply rates （P1=0, P2=44 and P3=109 μg P g–1 soil）. At shooting and lfowering stages, root respiration and carbon consumption increased with the elevate of P supply rates, regardless of water conditions, which achieved the minimum and maximum at P1 under 50–45% FC and P3 under 80–75% FC, respectively. However, total aboveground biomass and grain yield were higher at P2 under 80–75% FC; and decreased with high P application （P3）. The results indicated that rational or low P supply （80–75% of ifeld water capacity and 44 mg P kg–1 soil） should be recommended to improve grain yield by decreasing root carbon consumption in semiarid areas.展开更多
The properties and microscopic structure of tailings solidification bodies, the hardening mechanism of the fluorgypsum-based binder material （FBBM） and tailings solidification mechanism were investigated. FBBM consi...The properties and microscopic structure of tailings solidification bodies, the hardening mechanism of the fluorgypsum-based binder material （FBBM） and tailings solidification mechanism were investigated. FBBM consisted of 40% fluorgypsum,25%-50% blast furnace slag,10%-35% ordinary Portland cement clinker（OPCC） and 1% activator, which was good material in binding iron ore tailings.XRD analysis showed that the properties of tailings solidification bodies was related to its ettringite content.SEM and XRD analyses of tailings solidification bodies showed that the chemical reaction was produced between FBBM and tailings in the whole hydration process. The hydration of the resulting gel material covered the surface of the tailings particles and formed a gel structure. A large number of ettringite crystals and the remaining board-like gypsum crystals took each end and constituted the structural skeleton. The filamentous network-like calcium-silicate-hydrate（C-S-H） gel bonded firmly together with ettringite crystals, dehydrated gypsum crystals and granular tailings, and formed an extremely dense whole.展开更多
In addition to bacteria,the contribution of fungi to nitrous oxide(N_(2)O)production has been recognized but the responses of these two broad and unrelated groups of microorganisms to global environmental changes,atmo...In addition to bacteria,the contribution of fungi to nitrous oxide(N_(2)O)production has been recognized but the responses of these two broad and unrelated groups of microorganisms to global environmental changes,atmospheric nitrogen(N)deposition,and precipitation in terms of N_(2)O production are unclear.We studied how these two microbial-mediated N_(2)O production pathways responded to soil moisture conditions and to N addition in an N-limited temperate forest.Soils from a long-term N addition experiment in Changbai Mountain,northeastern China were incubated.Varied concentrations of cycloheximide and streptomycin,both inhibitors of fungal and bacterial activity,were used to determine the contributions of both to N_(2)O production in 66%,98%and 130%water-filled pore spaces(WFPS).The results showed that N_(2)O production decreased significantly with increasing cycloheximide concentration whereas streptomycin was only inhibiting N_(2)O emissions at 98%and 130%WFPS.The bacterial pathway of N_(2)O production in N-addition(Nadd)soil was significantly more dominant than that in untreated(Namb)soil.The difference in the fungal pathway of N_(2)O production between the soil with nitrogen addition and the untreated soil was not significant.Net N_(2)O emissions increased with increasing soil moisture,especially at 130%WFPS,a completely flooded condition.Bacteria dominated carbon dioxide(CO_(2))and N_(2)O emissions in Nadd soil and at 130%WFPS regardless of N status,while fungi dominated CO_(2)and N_(2)O emissions in soil without N addition at 66%and 98%WFPS.The results suggest that flooded soil is an important source of N_(2)O emissions and that bacteria might be better adapted to compete in fertile soils under anoxic conditions.展开更多
The composition and existing species of the reaction production of Hg2+ and X- (X= Cl, Br and l) under different conditions, and their absorption, Rayleigh scattering (RS) and resonance Rayleigh scattering (RRS) spect...The composition and existing species of the reaction production of Hg2+ and X- (X= Cl, Br and l) under different conditions, and their absorption, Rayleigh scattering (RS) and resonance Rayleigh scattering (RRS) spectra have been studied. The results show that the products exist in the form of nanoparticles as [HgX2]n aggregates under suitable conditions, and their average diameters increase with the increase of X- diameters. The diameters of [HgCl2]n [HgBr2]n and [Hgl2]n are less than 4 nm, equal to 9 nm and 70 nm respectively. There are bathchromic shifts gradually with the increase of X- diameters in their absorption spectra. The absorption bands of [HgCl2]n and [HgBr2]n locate at ultraviolet region. However, the absorption band of [Hgl2]n is obvious in visible light region. Among three particles, only [Hgl2]n exhibits a strong RRS and its scattering peak is at 580 nm. The main reasons leading to the enhancement of resonance scattering are the large size of nanoparticle, the formation of the interface and the location of light scattering in the absorption band. There are three important factors affecting resonance scattering spectrum: the quanta colored effect and molecular absorption spectrum of [Hgl2]n nanoparticle as well as instrumental factors which mainly include the light source's emission spectral characteristics and the signal response curve of detector.展开更多
The global financial crisis is striking the international financial market severely.Since July 2007,foreign banks and brokers have been suffering an enormous loss caused by the financial crisis.More than 160 thousand ...The global financial crisis is striking the international financial market severely.Since July 2007,foreign banks and brokers have been suffering an enormous loss caused by the financial crisis.More than 160 thousand jobs have been cut this year by financial institutions like Citibank,HSBC and Morgan Stanly,etc.However,what shows a strong contrast with展开更多
文摘The study of Nitrogen fixation, uptake, and leaching at different soil depths in the co-cultivation of maize and soybean under phosphorus fertilization is important for sustainable agriculture. This study was conducted in Quzhou, Hebei Province, China, with MC812 maize and Jidou12 soybean varieties. Soil samples were taken from each plot to create a composite sample. The results show that nitrogen concentration varies at different depths and is higher in all treatments between 40 and 100 cm. Incorporating intercropping of maize and soybeans into farming practices can lead to more sustainable and environmentally friendly agriculture in China.
文摘Intercropping, particularly the combination of maize and soybeans, has been widely recognized for its potential to improve nitrogen uptake and promote sustainable agriculture. This study examines the patterns of nitrogen uptake in maize and soybean intercropping systems under different growth stages and phosphorus fertilization levels and investigates the influence of nitrogen uptake on growth parameters such as plant height, leaf area, and biomass accumulation in the maize/soybean intercrop under different phosphorus fertilization regimes. The study also collected chlorophyll samples at different growth stages of maize in monoculture and intercropping with maize or soybean. The results showed that plant height was greater in V10 in both fertilized and unfertilized treatments for intercropped maize and soybean, and chlorophyll concentration was higher in VT intercropped maize. The results also showed a higher accumulation of biomass. Understanding the growth dynamics of these plants in monoculture and intercropping systems and the impact of fertilization practices is crucial for optimizing crop productivity and sustainability in agricultural systems.
基金Under the auspices of Supporting Program of the 'Eleventh Five-year Plan' for Science and Technology Research of China (No. 2009BAC61B02)China Postdoctoral Science Foundation Funded Project (No. 20100470561)
文摘Three-River Headwaters （TRH） region involved in this paper refers to the source region of the Changjiang （Yangtze） River, the Huanghe （Yellow） River and the Lancang River in China. Taking the TRH region of the Qing- hai-Tibet Plateau as a case, the annual evapotranspiration （ET） model developed by Zhang et al. （2001） was applied to evaluate mean annual ET in the alpine area, and the response of annual ET to land use change was analyzed. The plant-available water coefficient （w） of Zhang＇s model was revised by using vegetation-temperature condition index （VTCI） before annual ET was calculated in alpine area. The future land use scenario, an input of ET model, was spa- tially simulated by using the conversion of land use and its effects at small regional extent （CLUE-S） to study the re- sponse of ET to land use change. Results show that the relative errors between the simulated ET and that calculated by using water balance equation were 3.81% and the index of agreement was 0.69. This indicates that Zhang＇s ET model based on revised plant-available water coefficient is a scientific and practical tool to estimate the annual ET in the al- pine area. The annual ET in 2000 in the study area was 221.2 ram, 11.6 mm more than that in 1980. Average annual ET decreased from southeast to northwest, but the change of annual ET between 1980 and 2000 increased from southeast to northwest. As a vast and sparsely populated area, the population in the TRH region was extremely unbalanced and land use change was concentrated in very small regions. Thus, land use change had little effect on total annual ET in the study area but a great impact on its spatial distribution, and the effect of land use change on ET decreased with in- creasing precipitation. ET was most sensitive to the interconversion between forest and unused land, and was least sen- sitive to the interconversion between cropland and low-covered grassland.
基金Project supported by the Science and Technology Committee, Shanghai Municipality (No.02DJ14046).
文摘The effect of sodium dodecylbenzenesulfonate (SDBS), an anionic surfactant used widely in household products and industrial processes, on saturated hydraulic conductivities (Ksat) of an Anthrosol saturated with sodium (Na-soil) or calcium (Ca-soil) was analyzed in a laboratory experiment using the constant head method, and adsorption and dispersion experiments were also conducted to infer the possible mechanisms of Ksat fluctuations. The results showed that SDBS was more intensely adsorbed in the Ca-soil than in the Na-soil. With an increase in the SDBS concentration, the stability of the Na-soil suspensions decreased when the SDBS concentration was less than 1.2 mmol L-1 and then above this concentration, increased markedly, while the stability of the Ca-soil suspensions increased gradually at all SDBS concentrations studied. With an increase in the SDBS concentration, the Ksat of the Na-soil increased, which resulted mainly from the increase of water channels in the soil because of the coagulation of the soil particles, while the Ksat of Ca-soil decreased mainly on account of the clogging of partial water channels by precipitated Ca(DBS)2 and the fine soil particles generated.
基金supported by the National Nature Science Foundation of China (31300328, 31200335, 31470496)the "111" Program from State Administration of Foreign Experts Affairs (SAFEA) & Ministry of Education (MOE), China (2007B051)+1 种基金the Fundamental Research Funds for the Central Universities, China (lzujbky-2012-97, lzujbky-2015-ct02, lzujbky-2016-86)the funding from the State Key Laboratory of Grassland Agro-ecosystem in Lanzhou University, China
文摘In semiarid areas, cereal crops often alocate more biomass to root at the expense of aboveground yield. A pot experiment was conducted to investigate carbon consumption of roots and its impact on grain yield of spring wheat （Triticum aestivum L.） as affected by water and phosphorus （P） supply. A factorial design was used with six treatments namely two water regimes （at 80–75% and 50–45% ifeld capacity （FC）） and three P supply rates （P1=0, P2=44 and P3=109 μg P g–1 soil）. At shooting and lfowering stages, root respiration and carbon consumption increased with the elevate of P supply rates, regardless of water conditions, which achieved the minimum and maximum at P1 under 50–45% FC and P3 under 80–75% FC, respectively. However, total aboveground biomass and grain yield were higher at P2 under 80–75% FC; and decreased with high P application （P3）. The results indicated that rational or low P supply （80–75% of ifeld water capacity and 44 mg P kg–1 soil） should be recommended to improve grain yield by decreasing root carbon consumption in semiarid areas.
基金Funded by the National High Technology Research and Development Program (863 Project) (No.2009AA064004)the Fundamental Research Funds for the Central Universities (No.5082011 and No.1104003)
文摘The properties and microscopic structure of tailings solidification bodies, the hardening mechanism of the fluorgypsum-based binder material （FBBM） and tailings solidification mechanism were investigated. FBBM consisted of 40% fluorgypsum,25%-50% blast furnace slag,10%-35% ordinary Portland cement clinker（OPCC） and 1% activator, which was good material in binding iron ore tailings.XRD analysis showed that the properties of tailings solidification bodies was related to its ettringite content.SEM and XRD analyses of tailings solidification bodies showed that the chemical reaction was produced between FBBM and tailings in the whole hydration process. The hydration of the resulting gel material covered the surface of the tailings particles and formed a gel structure. A large number of ettringite crystals and the remaining board-like gypsum crystals took each end and constituted the structural skeleton. The filamentous network-like calcium-silicate-hydrate（C-S-H） gel bonded firmly together with ettringite crystals, dehydrated gypsum crystals and granular tailings, and formed an extremely dense whole.
基金the Key Research and Development Project from China’s Ministry of Science and Technology(2016YFA0600804)the National Natural Science Foundation of China[grant number 41575153,41430639,41673077,41675150 and 31800413]。
文摘In addition to bacteria,the contribution of fungi to nitrous oxide(N_(2)O)production has been recognized but the responses of these two broad and unrelated groups of microorganisms to global environmental changes,atmospheric nitrogen(N)deposition,and precipitation in terms of N_(2)O production are unclear.We studied how these two microbial-mediated N_(2)O production pathways responded to soil moisture conditions and to N addition in an N-limited temperate forest.Soils from a long-term N addition experiment in Changbai Mountain,northeastern China were incubated.Varied concentrations of cycloheximide and streptomycin,both inhibitors of fungal and bacterial activity,were used to determine the contributions of both to N_(2)O production in 66%,98%and 130%water-filled pore spaces(WFPS).The results showed that N_(2)O production decreased significantly with increasing cycloheximide concentration whereas streptomycin was only inhibiting N_(2)O emissions at 98%and 130%WFPS.The bacterial pathway of N_(2)O production in N-addition(Nadd)soil was significantly more dominant than that in untreated(Namb)soil.The difference in the fungal pathway of N_(2)O production between the soil with nitrogen addition and the untreated soil was not significant.Net N_(2)O emissions increased with increasing soil moisture,especially at 130%WFPS,a completely flooded condition.Bacteria dominated carbon dioxide(CO_(2))and N_(2)O emissions in Nadd soil and at 130%WFPS regardless of N status,while fungi dominated CO_(2)and N_(2)O emissions in soil without N addition at 66%and 98%WFPS.The results suggest that flooded soil is an important source of N_(2)O emissions and that bacteria might be better adapted to compete in fertile soils under anoxic conditions.
基金This work was supported by the National Natural Science Foundation of China(Grant No. 20175018),Natural Science Foundation of Chongqing and Natural Science Foundation of Guangxi Zhuang Autonomous Region(Grant No.0112016).
文摘The composition and existing species of the reaction production of Hg2+ and X- (X= Cl, Br and l) under different conditions, and their absorption, Rayleigh scattering (RS) and resonance Rayleigh scattering (RRS) spectra have been studied. The results show that the products exist in the form of nanoparticles as [HgX2]n aggregates under suitable conditions, and their average diameters increase with the increase of X- diameters. The diameters of [HgCl2]n [HgBr2]n and [Hgl2]n are less than 4 nm, equal to 9 nm and 70 nm respectively. There are bathchromic shifts gradually with the increase of X- diameters in their absorption spectra. The absorption bands of [HgCl2]n and [HgBr2]n locate at ultraviolet region. However, the absorption band of [Hgl2]n is obvious in visible light region. Among three particles, only [Hgl2]n exhibits a strong RRS and its scattering peak is at 580 nm. The main reasons leading to the enhancement of resonance scattering are the large size of nanoparticle, the formation of the interface and the location of light scattering in the absorption band. There are three important factors affecting resonance scattering spectrum: the quanta colored effect and molecular absorption spectrum of [Hgl2]n nanoparticle as well as instrumental factors which mainly include the light source's emission spectral characteristics and the signal response curve of detector.
文摘The global financial crisis is striking the international financial market severely.Since July 2007,foreign banks and brokers have been suffering an enormous loss caused by the financial crisis.More than 160 thousand jobs have been cut this year by financial institutions like Citibank,HSBC and Morgan Stanly,etc.However,what shows a strong contrast with
