A pot experiment was conducted to investigate the effects of nitrogen content [Nl （no fertilizer）, N2 （0.15 g.kg-l）, and N3 （0.3 g.kg 1）] on the growth and the hydraulic characteristics of peach seedlings under ...A pot experiment was conducted to investigate the effects of nitrogen content [Nl （no fertilizer）, N2 （0.15 g.kg-l）, and N3 （0.3 g.kg 1）] on the growth and the hydraulic characteristics of peach seedlings under different soil moisture conditions （Wl, W2 and W3, in which the soil water content was 45% to 55%, 60% to 70%, and 75% to 80% of the field water capacity, respectively） by using a specialized high pressure flow meter with a root chamber and a coupling, which was connected to plant organs. Leaf area and leaf hydraulic conductivity （KL） increased significantly in the seedlings because of increased soil moisture and N content. KL increased with leaf area. A linear correlation was documented between KL and leaf area. KL was higher in the morning and began to decline sharply after 16：00, at which KL declined after an initial increase. Soil moisture and N content enhanced shoot （Ks） and root （Kr） hydraulic conductivities, thereby improving the low soil moisture condition to a large extent. Ks and Kr of the seedlings were reduced by 32% and 27% respectively in N~, and by 14.7% and 9.4%, respectively in N2, and both in Wb compared with the control treatment. N3 had no significant effect on Ks and Kr under similar conditions. Linear negative correlations were observed between Kr and the excised root diameter as well as between Ks and the shoot stem diameter. The shoot-to-root ratio increased with in- crease in N content. The shoot-to-root ratio in N3 was increased by 14.37%, compared with N1 in W1 as well as by 12% and 4.39% in Wz and W3, respectively. Knowledge of the effects of soil moisture and N fertilizer on hydraulic characteristics and growth is important. Our results provide basic guidelines for the implementation of water-saving irrigation and fertilization management of nursery stock.展开更多
Rural drinking water safety is a growing concern in China. This study investigated the health risk of pollution of groundwater for the drinking water supply in Mingshan County, Ya＇an City, in Sichuan Province, China,...Rural drinking water safety is a growing concern in China. This study investigated the health risk of pollution of groundwater for the drinking water supply in Mingshan County, Ya＇an City, in Sichuan Province, China, using 46 samples from the years 1991 to 2010. Carcinogenic, non-carcinogenic, and total risks were assessed by the model recommended by the United States Environmental Protection Agency （U.S. EPA）. Thematic maps of the risks caused by single and multiple factors were generated from inverse distance weighting interpolation （IDW） and the geostatistical analysis functions of ArcGIS. The results show that the carcinogenic risks caused by chemicals in groundwater for drinking water supply are low, within the acceptable interval for risk management. However, non-carcinogenic risks are high and the number of sampling sites with risk values exceeding the standards amounted to 29. Non-carcinogenic risks of Cr6＋, nitrate, fluoride, and Fe at sites 43, 46, 50, 64, 67, and 74 were the sources that caused high total health risk. This study reveals the risk level of groundwater quality and orders of treatment of pollutants, and provides a scientific basis for groundwater management in this area.展开更多
In this study, based on the analysis of the catastrophic risk of rural drinking water, with the representative villages in Ya’an as study objects and setting the four evaluation standards: water quality, water quanti...In this study, based on the analysis of the catastrophic risk of rural drinking water, with the representative villages in Ya’an as study objects and setting the four evaluation standards: water quality, water quantity, the Guarantee Probability for water Supply and the Convenience Level of the Access to Water Supply as the ba- sic framework, a Rural Drinking Water Safety Assessment was developed (RDWSA). Research showed that Catastrophe Theory was applicable in the RDWSA. Adding RDWSA based on Catastrophe Theory to the supportive system for decision-making in Ecological Hydrographic Management Decision Support System of Ya’an helped obtain the rank and results of RDWSE by the automatic calculation of programs, which could assist the risk assessment and risk management associated with rural drinking water in Ya’an.展开更多
基金supported by the Chinese National Natural Science Fund(Grant No.50579066,50879073)Provincial Education Department Projects(11ZA072)
文摘A pot experiment was conducted to investigate the effects of nitrogen content [Nl （no fertilizer）, N2 （0.15 g.kg-l）, and N3 （0.3 g.kg 1）] on the growth and the hydraulic characteristics of peach seedlings under different soil moisture conditions （Wl, W2 and W3, in which the soil water content was 45% to 55%, 60% to 70%, and 75% to 80% of the field water capacity, respectively） by using a specialized high pressure flow meter with a root chamber and a coupling, which was connected to plant organs. Leaf area and leaf hydraulic conductivity （KL） increased significantly in the seedlings because of increased soil moisture and N content. KL increased with leaf area. A linear correlation was documented between KL and leaf area. KL was higher in the morning and began to decline sharply after 16：00, at which KL declined after an initial increase. Soil moisture and N content enhanced shoot （Ks） and root （Kr） hydraulic conductivities, thereby improving the low soil moisture condition to a large extent. Ks and Kr of the seedlings were reduced by 32% and 27% respectively in N~, and by 14.7% and 9.4%, respectively in N2, and both in Wb compared with the control treatment. N3 had no significant effect on Ks and Kr under similar conditions. Linear negative correlations were observed between Kr and the excised root diameter as well as between Ks and the shoot stem diameter. The shoot-to-root ratio increased with in- crease in N content. The shoot-to-root ratio in N3 was increased by 14.37%, compared with N1 in W1 as well as by 12% and 4.39% in Wz and W3, respectively. Knowledge of the effects of soil moisture and N fertilizer on hydraulic characteristics and growth is important. Our results provide basic guidelines for the implementation of water-saving irrigation and fertilization management of nursery stock.
基金supported by the Key Project Fund of the Sichuan Education Department (Grant No. 09ZA063),the Education Reform Project Fund of the Sichuan Education Department (Grant No. P09150)the National Innovative Project for College Students (Grant No. 00509204)the Youth Science and Technology Innovation Fund of Sichuan Agricultural University (Grant No. 00530300),the Talent Introduction Fund of Sichuan Agricultural University (Grant No. 00530301),and the Double-Support Plan of Sichuan Agricultural University (Grant No. 00570103)
文摘Rural drinking water safety is a growing concern in China. This study investigated the health risk of pollution of groundwater for the drinking water supply in Mingshan County, Ya＇an City, in Sichuan Province, China, using 46 samples from the years 1991 to 2010. Carcinogenic, non-carcinogenic, and total risks were assessed by the model recommended by the United States Environmental Protection Agency （U.S. EPA）. Thematic maps of the risks caused by single and multiple factors were generated from inverse distance weighting interpolation （IDW） and the geostatistical analysis functions of ArcGIS. The results show that the carcinogenic risks caused by chemicals in groundwater for drinking water supply are low, within the acceptable interval for risk management. However, non-carcinogenic risks are high and the number of sampling sites with risk values exceeding the standards amounted to 29. Non-carcinogenic risks of Cr6＋, nitrate, fluoride, and Fe at sites 43, 46, 50, 64, 67, and 74 were the sources that caused high total health risk. This study reveals the risk level of groundwater quality and orders of treatment of pollutants, and provides a scientific basis for groundwater management in this area.
文摘In this study, based on the analysis of the catastrophic risk of rural drinking water, with the representative villages in Ya’an as study objects and setting the four evaluation standards: water quality, water quantity, the Guarantee Probability for water Supply and the Convenience Level of the Access to Water Supply as the ba- sic framework, a Rural Drinking Water Safety Assessment was developed (RDWSA). Research showed that Catastrophe Theory was applicable in the RDWSA. Adding RDWSA based on Catastrophe Theory to the supportive system for decision-making in Ecological Hydrographic Management Decision Support System of Ya’an helped obtain the rank and results of RDWSE by the automatic calculation of programs, which could assist the risk assessment and risk management associated with rural drinking water in Ya’an.
