The purpose of this paper is to apply ＂Soil and Water Assessment Tool （SWAT）＂ model to assess the impacts of climate change and deforestation on stream discharge and sediment yield from Phu Luong watershed in Nort...The purpose of this paper is to apply ＂Soil and Water Assessment Tool （SWAT）＂ model to assess the impacts of climate change and deforestation on stream discharge and sediment yield from Phu Luong watershed in Northern Viet Nam. Among the three climate change scenarios B 1, B2, and A2, representing low, medium, and high levels of greenhouse gas emission, respectively were set up for Viet Nam, the B2 scenario was selected for this study. Two land use scenarios （S1-2030 and $2-2050） were formulated combination with climate change in WSAT simulation. In B2 climate change scenario, mean temperature increases 0.7℃（2030） and 1.3 ℃ （2050）; annual rainfall increases 2.1% （2030） and 3.80% （2050） respect to baseline scenario. The results show that the stream discharge is likely to increase in the future during the wet season with increasing threats of sedimentation.展开更多
A pot experiment was conducted to investigate the action mechanisms phorus （P） uptake of Capsicum annuum L. in a sterilized fossil Oxisol of arbuscular mycorrhizal （AM） fungi in phos- Three P levels of 0, 10 and 2...A pot experiment was conducted to investigate the action mechanisms phorus （P） uptake of Capsicum annuum L. in a sterilized fossil Oxisol of arbuscular mycorrhizal （AM） fungi in phos- Three P levels of 0, 10 and 200 mg kg-1 soil （P0, P10 and P200, respectively） without and with AM fungal inoculation were applied as Ca（H2PO4）2-H20. Shoot dry matter yields and shoot P uptake increased significantly （P 〉 0.05） by the inoculation of AM fungi at P0 and P10. Root length and P concentration in soil solution increased with the inoculation of AM fungi but the root：shoot ratio decreased or remained constant. Around 50% roots of inoculated plants were infected by AM and the external hyphae amounted to 20 m g^-1 soil at P10 and P200. The hyphae surface area of the infected root cylinder amounted to 11 and 2 cm^2 cm^-2 root at P0 and P10, respectively. The increased P uptake of inoculated plants was mainly because of an up to 5 times higher P influx of the infected root. Model calculations showed that the root alone could not have achieved the measured P influx in both infected and non-infected roots. But the P influx for hyphae calculated by the model was even much higher than the measured one. The P uptake capacity of hyphae introduced in the model was too high. Model calculations further showed that the depletion zone around roots or hyphae was very narrow. In the case of the root only 7% of the soil volume would contribute P to the plant, while in the case of hyphae it would be 100%. The results together with the model calculations showed that the increased P uptake of AM inoculated plants could be explained partly by the increased P concentration in the soil solution and by the increased P absorbing surface area coming from the external hyphae.展开更多
文摘The purpose of this paper is to apply ＂Soil and Water Assessment Tool （SWAT）＂ model to assess the impacts of climate change and deforestation on stream discharge and sediment yield from Phu Luong watershed in Northern Viet Nam. Among the three climate change scenarios B 1, B2, and A2, representing low, medium, and high levels of greenhouse gas emission, respectively were set up for Viet Nam, the B2 scenario was selected for this study. Two land use scenarios （S1-2030 and $2-2050） were formulated combination with climate change in WSAT simulation. In B2 climate change scenario, mean temperature increases 0.7℃（2030） and 1.3 ℃ （2050）; annual rainfall increases 2.1% （2030） and 3.80% （2050） respect to baseline scenario. The results show that the stream discharge is likely to increase in the future during the wet season with increasing threats of sedimentation.
基金Supported by the Higher Education Commission of Pakistan
文摘A pot experiment was conducted to investigate the action mechanisms phorus （P） uptake of Capsicum annuum L. in a sterilized fossil Oxisol of arbuscular mycorrhizal （AM） fungi in phos- Three P levels of 0, 10 and 200 mg kg-1 soil （P0, P10 and P200, respectively） without and with AM fungal inoculation were applied as Ca（H2PO4）2-H20. Shoot dry matter yields and shoot P uptake increased significantly （P 〉 0.05） by the inoculation of AM fungi at P0 and P10. Root length and P concentration in soil solution increased with the inoculation of AM fungi but the root：shoot ratio decreased or remained constant. Around 50% roots of inoculated plants were infected by AM and the external hyphae amounted to 20 m g^-1 soil at P10 and P200. The hyphae surface area of the infected root cylinder amounted to 11 and 2 cm^2 cm^-2 root at P0 and P10, respectively. The increased P uptake of inoculated plants was mainly because of an up to 5 times higher P influx of the infected root. Model calculations showed that the root alone could not have achieved the measured P influx in both infected and non-infected roots. But the P influx for hyphae calculated by the model was even much higher than the measured one. The P uptake capacity of hyphae introduced in the model was too high. Model calculations further showed that the depletion zone around roots or hyphae was very narrow. In the case of the root only 7% of the soil volume would contribute P to the plant, while in the case of hyphae it would be 100%. The results together with the model calculations showed that the increased P uptake of AM inoculated plants could be explained partly by the increased P concentration in the soil solution and by the increased P absorbing surface area coming from the external hyphae.
