Based on the assay of the total content and available content of the trace nutrient elements and the soil pH and organic matter of the soil samples,the characteristic of the available content of the trace nutrient ele...Based on the assay of the total content and available content of the trace nutrient elements and the soil pH and organic matter of the soil samples,the characteristic of the available content of the trace nutrient elements and their affecting factors are studied. The results show that the available B in western Jilin is in a middle level,the content in Nong'an is higher than that in the others; the available Mn is extremely abundant; the available Cu in Nong'an is obviously higher than other areas,and the content in Da'an differs greatly; the available Zn is in a middle level; the severe shortage of available Mo differs between different areas; and the available Fe is extremely abundant. The available Mn,Cu and Fe have significantly positive correlation with their total content; the available B has significantly positive correlation with pH,and Zn has obviously negative correlation with pH; the available Mn and Fe had significantly positive correlation with soil organic matter.展开更多
The comprehensive three-dimensional structures of an anti-cyclonic mesoscale eddy(AE)in the subtropical northwestern Pacific Ocean were investigated by combining the Argo floats profiles with enhanced vertical and tem...The comprehensive three-dimensional structures of an anti-cyclonic mesoscale eddy(AE)in the subtropical northwestern Pacific Ocean were investigated by combining the Argo floats profiles with enhanced vertical and temporal sampling and satellite altimetry data.The AE originated near the Kuroshio Extension and then propagated westward with mean velocity of 8.9 cm/s.Significant changes and evolutions during the AE’s growing stage(T1)and further growing stage(T2)were revealed through composite analysis.In the composite eddy core,maximum temperature(T)and salinity(S)anomalies were of 1.7(1.9)℃ and 0.04(0.07)psu in T1(T2)period,respectively.The composite T anomalies showed positive in almost whole depth,but the S anomalies exhibited a sandwich-like pattern.The eddy’s intensification and its influence on the intermediate ocean became more significant during its growth.The trapping depth increased from 400×10^4 Pa to 580×10^4 Pa while it was growing up,which means more water volume,heat and salt content in deeper layers can be transported.The AE was strongly nonlinear in upper oceans and can yield a typical mean volume transport of 0.17×10^6 m^3/s and a mean heat and salt transport anomaly of 3.6×10^11 W and–2.1×10^3 kg/s during the observation period.The Energy analysis showed that eddy potential and kinetic energy increased notably as it propagated westward and the baroclinic instability is the major energy source of the eddy growth.The variation of the remained Argo float trapped within the eddy indicated significant water advection during the eddy’s propagation.展开更多
Soil water deficit is increasingly threatening the sustainable vegetation restoration and ecological construction on the Loess Plateau of China due to the climate warming and human activities.To determine the response...Soil water deficit is increasingly threatening the sustainable vegetation restoration and ecological construction on the Loess Plateau of China due to the climate warming and human activities.To determine the response thresholds of Amygdalus pedunculata(AP)and Salix psammophila(SP)to soil water availability under different textural soils,we measured the changes in net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO2 concentration(Ci),leaf water potential(ψw),water use efficiency(WUE)and daily transpiration rate(Td)of the two plant species during soil water content(SWC)decreased from 100%field capacity(FC)to 20%FC in the sandy and loamy soils on the Loess Plateau in the growing season from June to August in 2018.Results showed that Pn,Gs,WUE and Td of AP and SP remained relatively constant at the beginning of soil water deficit but decreased rapidly as plant available soil water content(PASWC)fell below the threshold values in both the sandy and loamy soils.The PASWC thresholds corresponding to Pn,Gs and Ci of AP in the loamy soil(0.61,0.62 and 0.70,respectively)were lower than those in the sandy soil(0.70,0.63 and 0.75,respectively),whereas the PASWC thresholds corresponding to Pn,Gs and Ci of SP in the loamy soil(0.63,0.68 and 0.78,respectively)were higher than those in the sandy soil(0.58,0.62 and 0.66,respectively).In addition,the PASWC thresholds in relation to Td and WUE of AP(0.60 and 0.58,respectively)and SP(0.62 and 0.60,respectively)in the loamy soil were higher than the corresponding PASWC thresholds of AP(0.58 and 0.52,respectively)and SP(0.55 and 0.56,respectively)in the sandy soil.Furthermore,the PASWC thresholds for the instantaneous gas exchange parameters(e.g.,Pn and Gs)at the transient scale were higher than the thresholds for the parameters(e.g.,Td)at the daily scale.Our study demonstrates that different plant species and/or different physiological parameters exhibit different thresholds of PASWC and that the thresholds are affected by soil texture.The result can provide guidance for the rational allocation and sustainable management of reforestation species under different soil conditions in the loess regions.展开更多
Water yield calculation and mapping are of great importance to water resource planning and management and hydropower station construction. A water yield model based on InVEST was employed to estimate water runoff in t...Water yield calculation and mapping are of great importance to water resource planning and management and hydropower station construction. A water yield model based on InVEST was employed to estimate water runoff in the Xitiaoxi River basin. The data included land use and land cover, average annual precipitation and potential evapotranspiration, soil depth, and plant available water content. In order to test model accuracy the natural runoff of Xitiaoxi River was estimated based on linear regression relation of rainfall-runoff in a ‘reference period’. After repeated validation, when the Z value was 6.5 the water yield was 8.30 E＋8 m3 and this was a smaller difference with natural runoff. From the distribution of water yield, south and southwestern areas of the watershed had higher water yield volumes per hectare.展开更多
Every year about 1,500 ha of land is reclaimed from the sea along the coastline of Jiangsu Province,China.It is important to characterize the hydraulic properties of this reclaimed land to be able to predict and manag...Every year about 1,500 ha of land is reclaimed from the sea along the coastline of Jiangsu Province,China.It is important to characterize the hydraulic properties of this reclaimed land to be able to predict and manage salt and water movement for amelioration of these saline soils.In this paper,we report hydraulic properties of these salt-affected soils.The pressure-plate method,constant head method,the crust method and Klute’s method were used in this study.The satu-rated hydraulic conductivities of the soils ranged from 128.66 to 141.26 cm/day and decreased with increasing soil depth.The unsaturated hydraulic conductivities followed an expo-nential function of pressure head.The soil water retention curves were similar for three soil layers in the soil.The satu-rated water content,field capacity and wilting point decreased with increasing soil depth.Plant available water contents of the three layers in the soil profile were 0.21,0.20 and 0.19 cm3/cm3,respectively.The unsaturated soil water diffu-sivity of the studied soils ranged from 0.07 to 10.46 cm^(2)/min,and was related to the water content via an exponential relationship.展开更多
基金Supported by a Sub-project "Ecological Geochemical Survey of Oil Crop (sunflower) Producing Area in Western Jilin" of the Project of China Geological Survey and Jilin Provincial Government " Agricul-tural Geological Survey of Jilin Province"~~
文摘Based on the assay of the total content and available content of the trace nutrient elements and the soil pH and organic matter of the soil samples,the characteristic of the available content of the trace nutrient elements and their affecting factors are studied. The results show that the available B in western Jilin is in a middle level,the content in Nong'an is higher than that in the others; the available Mn is extremely abundant; the available Cu in Nong'an is obviously higher than other areas,and the content in Da'an differs greatly; the available Zn is in a middle level; the severe shortage of available Mo differs between different areas; and the available Fe is extremely abundant. The available Mn,Cu and Fe have significantly positive correlation with their total content; the available B has significantly positive correlation with pH,and Zn has obviously negative correlation with pH; the available Mn and Fe had significantly positive correlation with soil organic matter.
基金The National Program on Global Change and Air-Sea Interaction under contract No.GASI-IPOVAI-01-02the program for scientific research start-up funds of Guangdong Ocean University under contract No.R19011the fund of Southern Marine Science and Engineering Guangdong Laboratory(Zhanjiang)under contract No.ZJW-2019-08。
文摘The comprehensive three-dimensional structures of an anti-cyclonic mesoscale eddy(AE)in the subtropical northwestern Pacific Ocean were investigated by combining the Argo floats profiles with enhanced vertical and temporal sampling and satellite altimetry data.The AE originated near the Kuroshio Extension and then propagated westward with mean velocity of 8.9 cm/s.Significant changes and evolutions during the AE’s growing stage(T1)and further growing stage(T2)were revealed through composite analysis.In the composite eddy core,maximum temperature(T)and salinity(S)anomalies were of 1.7(1.9)℃ and 0.04(0.07)psu in T1(T2)period,respectively.The composite T anomalies showed positive in almost whole depth,but the S anomalies exhibited a sandwich-like pattern.The eddy’s intensification and its influence on the intermediate ocean became more significant during its growth.The trapping depth increased from 400×10^4 Pa to 580×10^4 Pa while it was growing up,which means more water volume,heat and salt content in deeper layers can be transported.The AE was strongly nonlinear in upper oceans and can yield a typical mean volume transport of 0.17×10^6 m^3/s and a mean heat and salt transport anomaly of 3.6×10^11 W and–2.1×10^3 kg/s during the observation period.The Energy analysis showed that eddy potential and kinetic energy increased notably as it propagated westward and the baroclinic instability is the major energy source of the eddy growth.The variation of the remained Argo float trapped within the eddy indicated significant water advection during the eddy’s propagation.
基金This study was financially supported by the National Natural Science Foundation of China(41601221)the Ministry of Science and Technology of China(2016YFC0501605)+2 种基金the Youth Innovation Promotion Association of Chinese Academy of Sciences(2019052)the Bingwei Outstanding Young Talent Project from the Institute of Geographical Sciences and Natural Resources Research,Chinese Academy of Sciences(2017RC203)the Scientific Research Program from the State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resources(A314021402-2010)。
文摘Soil water deficit is increasingly threatening the sustainable vegetation restoration and ecological construction on the Loess Plateau of China due to the climate warming and human activities.To determine the response thresholds of Amygdalus pedunculata(AP)and Salix psammophila(SP)to soil water availability under different textural soils,we measured the changes in net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO2 concentration(Ci),leaf water potential(ψw),water use efficiency(WUE)and daily transpiration rate(Td)of the two plant species during soil water content(SWC)decreased from 100%field capacity(FC)to 20%FC in the sandy and loamy soils on the Loess Plateau in the growing season from June to August in 2018.Results showed that Pn,Gs,WUE and Td of AP and SP remained relatively constant at the beginning of soil water deficit but decreased rapidly as plant available soil water content(PASWC)fell below the threshold values in both the sandy and loamy soils.The PASWC thresholds corresponding to Pn,Gs and Ci of AP in the loamy soil(0.61,0.62 and 0.70,respectively)were lower than those in the sandy soil(0.70,0.63 and 0.75,respectively),whereas the PASWC thresholds corresponding to Pn,Gs and Ci of SP in the loamy soil(0.63,0.68 and 0.78,respectively)were higher than those in the sandy soil(0.58,0.62 and 0.66,respectively).In addition,the PASWC thresholds in relation to Td and WUE of AP(0.60 and 0.58,respectively)and SP(0.62 and 0.60,respectively)in the loamy soil were higher than the corresponding PASWC thresholds of AP(0.58 and 0.52,respectively)and SP(0.55 and 0.56,respectively)in the sandy soil.Furthermore,the PASWC thresholds for the instantaneous gas exchange parameters(e.g.,Pn and Gs)at the transient scale were higher than the thresholds for the parameters(e.g.,Td)at the daily scale.Our study demonstrates that different plant species and/or different physiological parameters exhibit different thresholds of PASWC and that the thresholds are affected by soil texture.The result can provide guidance for the rational allocation and sustainable management of reforestation species under different soil conditions in the loess regions.
基金National Major Water Pollution Control Project(No.2008ZX07526-007)
文摘Water yield calculation and mapping are of great importance to water resource planning and management and hydropower station construction. A water yield model based on InVEST was employed to estimate water runoff in the Xitiaoxi River basin. The data included land use and land cover, average annual precipitation and potential evapotranspiration, soil depth, and plant available water content. In order to test model accuracy the natural runoff of Xitiaoxi River was estimated based on linear regression relation of rainfall-runoff in a ‘reference period’. After repeated validation, when the Z value was 6.5 the water yield was 8.30 E＋8 m3 and this was a smaller difference with natural runoff. From the distribution of water yield, south and southwestern areas of the watershed had higher water yield volumes per hectare.
文摘Every year about 1,500 ha of land is reclaimed from the sea along the coastline of Jiangsu Province,China.It is important to characterize the hydraulic properties of this reclaimed land to be able to predict and manage salt and water movement for amelioration of these saline soils.In this paper,we report hydraulic properties of these salt-affected soils.The pressure-plate method,constant head method,the crust method and Klute’s method were used in this study.The satu-rated hydraulic conductivities of the soils ranged from 128.66 to 141.26 cm/day and decreased with increasing soil depth.The unsaturated hydraulic conductivities followed an expo-nential function of pressure head.The soil water retention curves were similar for three soil layers in the soil.The satu-rated water content,field capacity and wilting point decreased with increasing soil depth.Plant available water contents of the three layers in the soil profile were 0.21,0.20 and 0.19 cm3/cm3,respectively.The unsaturated soil water diffu-sivity of the studied soils ranged from 0.07 to 10.46 cm^(2)/min,and was related to the water content via an exponential relationship.
