The distribution and variations of ammonium and the ammonia neutralization effect on acid rain were examined in East Asia during the period of 2000 05 using observed wet deposition data from the Acid Deposition Monito...The distribution and variations of ammonium and the ammonia neutralization effect on acid rain were examined in East Asia during the period of 2000 05 using observed wet deposition data from the Acid Deposition Monitoring Network in East Asia (EANET).Observational trends show a high proportion of NH 4 + in the total cations,with a six-year mean proportion of over 20% for continental and inland regions.The concentrations and deposition of NH 4 + were higher in western China and Vietnam than in other regions.The annual variations in NH 4 + concentration were smooth in most of the regions,except for southern China and Vietnam,where the NH 4 + concentrations increased,and western China,where the NH 4 + concentrations decreased.The neutralization factors (NFs) of NH 4 + indicate that ammonia has a great neutralization capability toward acid rain,including for the regions with low NH 4 + concentrations,such as Japan.The NFs were high in summer,with no obvious discrepancies between the northern and southern stations.However,the correlation coefficients between NH 4 + concentrations and rain pH values imply that the ammonia neutralization effects on the pH values were distinct only at southern China and southern Japan stations.The neutralization of precipitation by ammonia was estimated by comparing the discrepancies between the observed pH values and the pH values calculated without ammonia consuming the H + in NH 4 +.The results demonstrate that ammonia may increase annual mean pH values by 0.4 0.7 in southern China and by 0.15 0.25 in southern Japan.展开更多
With the rapid development of the economy,acid rain has become one of the major environmental problems that endanger human health.Being the largest developing country,the environmental problems caused by acid rain are...With the rapid development of the economy,acid rain has become one of the major environmental problems that endanger human health.Being the largest developing country,the environmental problems caused by acid rain are of increasing concern with the rapid industrialization and urbanization in China.Recently,many researchers have focused on acid rain.To better understand the temporal and spatial dynamics of acid rain in China,the monitoring data on acid rain from 1998 to 2018 were studied using ArcGIS 10.2.The results show that the proportion of acid rain cities,the frequency,and the area of acid rain were decreasing,however,the situation still remains serious.Overall,the chemical type of acid rain was mainly sulfuric acid rain.However,the concentration ratio of SO_(4)^(2-)/NO_(3)^(-)-decreased by 81.90%in 2018 compared with 1998,and presented a decreasing trend,which indicates that the contribution of nitrate to precipitation acidity has been increasing year by year.This research will help us to understand the distribution characteristics and causes of acid rain in China,and it may provide an effective reference for the prevention and control of acid rain in China.展开更多
Strongly acidic soils （pH 〈 5.0） are detrimental to tea （Camellia sinensis） production and quality. Little information exists on the ability of surface amendments to ameliorate subsoil acidity in the tea garden s...Strongly acidic soils （pH 〈 5.0） are detrimental to tea （Camellia sinensis） production and quality. Little information exists on the ability of surface amendments to ameliorate subsoil acidity in the tea garden soils. A 120-d glasshouse column leaching experiment was conducted using commonly available soil ameliorants. Alkaline slag （AS） and organic residues, pig manure （PM） and rapeseed cake （RC） differing in ash alkalinity and C/N ratio were incorporated alone and in combination into the surface （0-15 cm） of soil columns （10 cm internal diameter x 50 cm long） packed with soil from the acidic soil layer （15-30 cm） of an Ultisol （initial pH -- 4.4）. During the 120-d experiment, the soil columns were watered （about 127 mm over 9 applications） according to the long-term mean annual rainfall （1 143 mm） and the leachates were collected and analyzed. At the end of the experiment, soil columns were partitioned into various depths and the chemical properties of soil were measured. The PM with a higher C/N ratio increased subsoil pH, whereas the RC with a lower C/N ratio decreased subsoil pH. However, combined amendments had a greater ability to reduce subsoil acidity than either of the amendments alone. The increases in pH of the subsoil were mainly ascribed to decreased base cation concentrations and the decomposition of organic anions present in dissolved organic carbon （DOC） and immobilization of nitrate that had been leached down from the amended layer. A significant （P 〈 0.05） correlation between alkalinity production （reduced exchangeable acidity - N-cycle alkalinity） and alkalinity balance （net alkalinity production - N-cycle alkalinity） was observed at the end of the experiment. Additionally, combined amendments significantly increased （P ~ 0.05） subsoil cation concentrations and decreased subsoil A1 saturation （P 〈 0.05）. Combined applications of AS with organic amendments to surface soils are effective in reducing subsoil acidity in high-rainfall areas. Further investigations under field conditions and over longer timeframes are needed to fully understand their practical effectiveness in ameliorating acidity of deeper soil layers under naturally occurring leaching regimes.展开更多
基金supported by the NationalBasic Research Program of China (Grant No. 2005CB422205)
文摘The distribution and variations of ammonium and the ammonia neutralization effect on acid rain were examined in East Asia during the period of 2000 05 using observed wet deposition data from the Acid Deposition Monitoring Network in East Asia (EANET).Observational trends show a high proportion of NH 4 + in the total cations,with a six-year mean proportion of over 20% for continental and inland regions.The concentrations and deposition of NH 4 + were higher in western China and Vietnam than in other regions.The annual variations in NH 4 + concentration were smooth in most of the regions,except for southern China and Vietnam,where the NH 4 + concentrations increased,and western China,where the NH 4 + concentrations decreased.The neutralization factors (NFs) of NH 4 + indicate that ammonia has a great neutralization capability toward acid rain,including for the regions with low NH 4 + concentrations,such as Japan.The NFs were high in summer,with no obvious discrepancies between the northern and southern stations.However,the correlation coefficients between NH 4 + concentrations and rain pH values imply that the ammonia neutralization effects on the pH values were distinct only at southern China and southern Japan stations.The neutralization of precipitation by ammonia was estimated by comparing the discrepancies between the observed pH values and the pH values calculated without ammonia consuming the H + in NH 4 +.The results demonstrate that ammonia may increase annual mean pH values by 0.4 0.7 in southern China and by 0.15 0.25 in southern Japan.
基金The National Natural Science Foundation of China(U1701236)The Science and Technology Planning Project of Guangdong Province(2019B030301007)。
文摘With the rapid development of the economy,acid rain has become one of the major environmental problems that endanger human health.Being the largest developing country,the environmental problems caused by acid rain are of increasing concern with the rapid industrialization and urbanization in China.Recently,many researchers have focused on acid rain.To better understand the temporal and spatial dynamics of acid rain in China,the monitoring data on acid rain from 1998 to 2018 were studied using ArcGIS 10.2.The results show that the proportion of acid rain cities,the frequency,and the area of acid rain were decreasing,however,the situation still remains serious.Overall,the chemical type of acid rain was mainly sulfuric acid rain.However,the concentration ratio of SO_(4)^(2-)/NO_(3)^(-)-decreased by 81.90%in 2018 compared with 1998,and presented a decreasing trend,which indicates that the contribution of nitrate to precipitation acidity has been increasing year by year.This research will help us to understand the distribution characteristics and causes of acid rain in China,and it may provide an effective reference for the prevention and control of acid rain in China.
基金This study was supported by the National Natural Science Foundation of China （No. 41401336）, the Na- tural Science Foundation of Jiangsu Province, China （No. BK20130105）, the State Key Laboratory of Soil and Sustainable Agriculture, Chinese Academy of Sci-ence （No. Y412201452）, and the Environmental Pro- tection Public Benefit Research Foundation of China （No. 201309036）. We thank the three anonymous refe- rees for their helpful comments.
文摘Strongly acidic soils （pH 〈 5.0） are detrimental to tea （Camellia sinensis） production and quality. Little information exists on the ability of surface amendments to ameliorate subsoil acidity in the tea garden soils. A 120-d glasshouse column leaching experiment was conducted using commonly available soil ameliorants. Alkaline slag （AS） and organic residues, pig manure （PM） and rapeseed cake （RC） differing in ash alkalinity and C/N ratio were incorporated alone and in combination into the surface （0-15 cm） of soil columns （10 cm internal diameter x 50 cm long） packed with soil from the acidic soil layer （15-30 cm） of an Ultisol （initial pH -- 4.4）. During the 120-d experiment, the soil columns were watered （about 127 mm over 9 applications） according to the long-term mean annual rainfall （1 143 mm） and the leachates were collected and analyzed. At the end of the experiment, soil columns were partitioned into various depths and the chemical properties of soil were measured. The PM with a higher C/N ratio increased subsoil pH, whereas the RC with a lower C/N ratio decreased subsoil pH. However, combined amendments had a greater ability to reduce subsoil acidity than either of the amendments alone. The increases in pH of the subsoil were mainly ascribed to decreased base cation concentrations and the decomposition of organic anions present in dissolved organic carbon （DOC） and immobilization of nitrate that had been leached down from the amended layer. A significant （P 〈 0.05） correlation between alkalinity production （reduced exchangeable acidity - N-cycle alkalinity） and alkalinity balance （net alkalinity production - N-cycle alkalinity） was observed at the end of the experiment. Additionally, combined amendments significantly increased （P ~ 0.05） subsoil cation concentrations and decreased subsoil A1 saturation （P 〈 0.05）. Combined applications of AS with organic amendments to surface soils are effective in reducing subsoil acidity in high-rainfall areas. Further investigations under field conditions and over longer timeframes are needed to fully understand their practical effectiveness in ameliorating acidity of deeper soil layers under naturally occurring leaching regimes.
