Estimation and Mapping of Nitrogen Uptake by Forest in South Korea

Regional air pollution in northeast Asia is an emerging environmental problem requiring long-term impact assessment of acidic deposition. In this study, the gridded distribution of nitrogen uptake led by both growing forests and harvested biomass for eight tree species: Japanese Larch, Red pine, Korean pine, Oak tree, Chestnut, Other Conifers, Other broad leaved trees, and Mixed forest was identified to estimate critical loads for nitrogen over South Korea. The gridded spatial distribution of averaged nitrogen uptake was mapped by 0.125° Latitude × 0.125° Longitude resolution. The results showed that net uptake of nitrogen led by both growth and harvested biomass was totaled at 438 mol_c ha^?1 year^?1 among which harvested biomass contribution was estimated to be 25 mol_c ha^?1 year^?1, yielding a very small fraction of total nitrogen uptake presumably due to the younger stages of forest in South Korea.     

Evalution of Acid Deposition in Korea

This study was carried out to evaluate acid depositions and to understand their effect. Wet precipitation has been collected at twenty-four sites in Korea for one year of 1999. The ion concentrations such as H⁺, Na⁺, K⁺, Mg²⁺, NH₄ ⁺, Ca²⁺, Cl^?, NO₃ ^? and SO₄ ^2? were chemically analyzed and determined. Precipitation had wide range of pH(3.5～8.5), and volume-weighted average was 5.2. The contribution amounts of Cl^?, SO₄ ^2? and NO₃ ^? in anion were shown to be 54%, 32%, and 14%, respectively and those of Na⁺ and NH₄ ⁺ in cation were 32% and 25%. The ratios of Cl^? and Mg²⁺ to Na⁺ in precipitation were similar to those of seawater, which imply that great amount of Cl^? and Mg²⁺ in precipitation could be originated from seawater. The concentration of H⁺ is little related with SO₄ ^2?, NO₃ ^? and Cl^? ions, whereas nss^?SO₄ ^2? and NO₃ ^? are highly correlated with NH₄ ⁺, which could suggest that great amount of SO₄ ^2? and NO₃ ^? exist in the form of ammonium associated salt. The annual wet deposition amounts (g m^?2year^?1) of SO₄ ^2?, NO₃ ^?, Cl^?, H⁺, NH₄ ⁺, Na⁺, K⁺, Ca²⁺ and Mg²⁺ were estimated as 0.88～4.89, 0.49～4.37, 0.30～9.80, 0.001～0.031, 0.06～2.15, 0.27～4.27, 0.10～3.81, 0.23～1.59 and 0.03～0.63.     

Modelling and Mapping Ozone Deposition in Europe

A new dry deposition module has been developed for European-scale mapping and modelling of ozone deposition fluxes (Emberson et al., 2000a,b). The module is being implemented in the photochemical long-range transport model of EMEP that is currently used to estimate exceedance of the existing critical levels for ozone within the UN ECE LRTAP programme. The deposition model evaluates the atmospheric, boundary layer and surface resistances to ozone transfer with the calculation of the dry deposition velocity performed according to a standard resistance formulation. The approach differs from other existing methods through the use of a detailed stomatal uptake model that describes stomatal conductance as a function of plant species, phenology and four environmental variables (air temperature, solar radiation, water vapour pressure deficit and soil moisture deficit). Comparison of preliminary model outputs for selected land-cover types indicate that the model is capable of predicting the seasonal and diurnal range in deposition velocities that have been reported previously in the literature. The application of this deposition scheme enables calculations of ambient ozone concentrations to be made using a biologically based method that can distinguish stomatal and non-stomatal components of total ozone deposition. The ability to estimate stomatal ozone fluxes (according to vegetation type, phenology and spatial location) that are consistent with evaluations of atmospheric ozone concentrations will be helpful in future assessments of ozone impacts to vegetation.     

Long-Term Base Cation Balances of Forest Mineral Soils in Finland

Long-term base cation balances (Ca, Mg and K) for forest mineral soils in Finland were calculated with mass balance methods. The aim of the study was to identify the areas in which weathering and base cation deposition do not support leaching and uptake of base cations by vegetation. The effect of stem harvesting and whole-tree harvesting on the base cation balances was studied and preliminary calculations were made about the amounts of ash needed for compensation of the potential base cation depletion. The effect of sulphur emission reduction till 2010 was also considered. The study demonstrated that there would be depletion of base cations in forest mineral soils in southern, central and northeastern Finland (40–50% of the grids) in the long term if whole-tree harvesting would be practised. Theoretical calculations showed that ash application would be most useful in those areas to compensate the base cation depletion. If stem harvesting is practised, only small areas (20%) in southwestern and southeastern Finland and northeastern Lapland would show depletion of base cations in the long term.     

Effects of Climate, Land Management, and Sulfur Deposition on Soil Base Cation Supply in National Forests of the Southern Appalachian Mountains

Forest soils having low exchangeable calcium (Ca) and other nutrient base cation (BC) reserves may induce nutrient deficiencies in acid-sensitive plants and impact commercially important tree species. Past and future depletion of soil BC in response to acidic sulfur (S) deposition, forest management, and climate change alter the health and productivity of forest trees. This study used a process model (Model of Acidification of Groundwater in Catchments [MAGIC]) to address a number of questions related to soil BC status for a group of 65 streams and their watersheds in the southern Blue Ridge physiographic province of the southern Appalachian Mountains. Future S deposition to the study watersheds used for the Base Scenario was specified according to proposed reductions in S emissions at the time of this study, representing a reduction of 42 % of ambient S deposition by 2020. Twenty additional simulations were considered, reflecting four alternate S deposition scenarios (6 %, 58 %, 65 %, and 78 % reduction), and various changes in timber harvest, temperature, and precipitation. Base Scenario soil exchangeable Ca and % base saturation showed decreasing trends from 1860 to 2100. Changes in tree harvesting had the largest effect on stream sum of base cations (SBC) and soil BC supply. Each of the scenario projections indicated that median year 2100 soil exchangeable Ca will be at least 20 % lower than pre-industrial values. The simulations suggested that substantial mass loss of soil BC has already occurred since pre-industrial times. Nearly the same magnitude of BC loss is expected to occur over the next 145 years, even under relatively large additional future reductions in S deposition.     

Wet Deposition of Pollutants and Precipitation Patterns Classified by Cluster Analysis of 850 hPa Geopotential Height in South Korea

Synoptic meteorological conditions for precipitating systems over South Korea are characterized into several similar types using a clustering technique based on the K-mean principles with the daily mean 850 hPa grid pointed geopotential height in the spatial resolution of 5° × 5° data obtained from NCEP in the domain of 25° ～ 50°N and 110° ～ 140°E for five years from 1994 to 1998. The consecutive three-day gridded NCEP data with the precipitation event on the last day over South Korea are used for the cluster analysis. With the use of the precipitation chemistry monitored data at 8 sites in South Korea, wet depositions of SO₄ ^2?, NO₃ ^? and NH₄ ⁺ belonging to each cluster are examined to identify the deposition levels for each cluster. The result indicates that the present methodology is found to identify the deposition levels clearly and be used more practically in the field of acid rain study without heavy computational requirement.     

Base Cation Fluxes in Mountain Landscapes of Lake Baikal Southern Shore

Abstract

Assessing base cation [calcium (Ca²⁺), magnesium (Mg²⁺), potassium (K⁺)] fluxes is necessary for determining ecosystem stability. This study was conducted in the Osinovka River catchment located on the Khamar‐Daban Ridge, South Baikal, which is characterized by high precipitation (more than 1700 mm per annum). The contributions of different ecosystem components such as atmospheric deposition, soil exchange pool, minerals, vegetation, surface water, and groundwater into the total base cations flux were evaluated, combining the strontium isotope approach and budget study. Results show the leading role of atmosphere in ecosystem supply with base cations. The atmosphere contributes 48% of total base cations flux, and its contributions to plant‐available nutrition pools of both organic and mineral horizons are equal to 50%. This makes the vitality of vegetation, to a great extent, dependent on the stability of atmospheric chemistry.     

Estimation of Ammonia Emission in South Korea

The importance of ammonia (NH₃) in the atmosphere andits role in acidification is increasingly recognized. Adetailed emission inventory of NH₃ for South Korea iscarried out for different sources using emission factors.Results indicate that the emission of ammonia has increasedby 21% over the last 11 yr from 143 000 t yr^-1 in1988 to 181 000 t yr^-1 in 1998. The major contributorsto the NH₃ emission in South Korea are livestock andfertilizer application that account for 70 and 26% oftotal NH₃ emission, respectively. The 11 × 14 km (0.125° long. × 0.125° lat.) grid distribution of emission of ammonia shows an maximum in the Yochon area due to the largest fertilizer factory and relatively wide regions of high NH₃ emission in thenorthwestern part of South Korea due to a great number of livestock. It is found that the nitrogen ratio of wet deposition of NH₄ ⁺ to emission of NH₃ in SouthKorea is averaged to be 0.45.     

Long-Term Effects of Wheat Production Management Practices on Exchangeable Base Cations and Cation Exchange Capacity of a Plinthosol in Semi-arid South Africa

Changes in soil fertility indicators are mainly the result of management practices and usually influence crop yields over the long term. This study shows the effects of long-term wheat production management practices on exchangeable base cations and cation exchange capacity (CEC). Applied field treatments included two methods of straw management (unburned, burned), three methods of tillage (no tillage, stubble mulch, plowing), and two methods of weeding (chemical, mechanical). Samples were collected at six soil depths and analyzed for potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), and CEC. Burned wheat straw resulted in greater K and lower Ca concentrations compared to unburned wheat straw. No-tillage treatment increased K, Ca, Mg, Na, and CEC compared to both stubble mulch and plowing. Chemical weeding improved Na and CEC compared to mechanical weeding. The treatment combinations had positive influences mainly on CEC. Unburned straw and moldboard plowing with respect to burned straw and no tillage enhanced grain yield with 8%.     

模拟氮沉降对红壤阳离子淋溶的影响研究

以中国科学院红壤生态实验站林草生态试验区阔叶林红壤为对象,通过土壤淋溶试验,模拟研究了不同氮输入量对南方红壤阳离子(Ca2 、Mg2 、K 、Na 、H 和A l3 )淋溶的影响。结果表明,无氮(0mgN/月.柱)、低氮(7.8 mg N/月.柱)、中氮(26 mgN/月.柱)和高氮(52 mg N/月.柱)输入处理下,土壤交换态盐基淋溶总量分别占土壤交换性盐基总量的13.6%,18.4%,27.7%,48.1%。不同的盐基离子对氮输入的反应不同,Ca2 和Mg2 淋溶量随氮输入量的增加而增加,对Na 和K 则无明显影响。土壤交换态离子中随淋洗液输出最多的为Ca2 (无氮、低氮、中氮和高氮输入处理的土壤交换态输出量占土壤交换态的比例分别为22.6%,31.4F.7%,82.5%),其次为Na (其比例分别为16.0%,10.7%,17.6%,26.3%),最少的为Mg2 (其比例分别为5.0%,6.9%,11.1%,16.9%),无土壤交换性K 输出。随氮输入的增加,土壤致酸离子H 和Al3 的淋溶量增加。大气氮沉降的增加,将加速南方红壤的养分淋失和相邻水体的酸化。     

Mapping of Concentrations in Europe Combining Measurements and Acid Deposition Models

Measurements of air and precipitation quality have been carried out within the EMEP programme under the Convention on Long Range Transboundary Air Pollution (LRTAP) since 1978. Approximately 100 rural sites are currently in operation. The Meteorological Synthesising Centre-West (MSC-W) operates two EMEP models estimating transboundary fluxes of air pollutants, a two-dimensional Lagrangian model and a three-dimensional Eulerian model. Traditionally kriging has been used to produce gridded concentration fields from observed data for comparison with modelled data. This paper describes a method for producing optimal fields based on both point measurements and. The difference between modelled and measured values in each measurement point is interpolated to give a smooth two-dimensional expression for the discrepancy between the two data sets. A combined map is derived by adjusting the modelled values with the interpolated difference weighted by the distance to the nearest measurement point. The method has been applied to sulphur and nitrogen measurements in air and precipitation from the EMEP network and modelled results in a 150×150 km grid from the EMEP Lagrangian model. The combined maps give improved regional concentration fields combining characteristics from both the measured and modelled data sets depending on the distance to the measurement points. Comparison with results from the higher resolution Eulerian model shows good agreement.     

Elemental and Base Anions Deposition in the Snow Cover of North-Eastern Estonia

Snow samples from 18 sites in Estonia were collected in February and March 1996 after 72–110 days of permanent snow cover. Three snow layers corresponding to different snow accumulation periods were separated in each sampling site. Snow water samples were analysed for sulphate (SO₄ ^2-), nitrate (NO₃ ^-), and chloride (Cl^-) ions and elemental composition. Deposition fluxes of 27 chemical species were used for factor, cluster and correlation analysis. The effects of cement dust, oil shale fly ash, sulphur dioxide and chlorine from emissions of thermal power plants were distinguished. A large number of trace metals are strongly correlated with each other (R > 0.8) and with macro-components (except NO₃ ^-), which refers to a common origin, identified as the mineral part of oil shale. Deposition fluxes of Ca, Mg, SO₄ ^2- and a number of mineral components exceed near the power plants 1–2 decimal orders the background value. The deposition fluxes in forested sites are up to 2 times higher than in open land sites. This difference may be caused by more efficient turbulent transfer over rougher surface. It is suggested, that NO₃ ^- and Zn originate mainly and Pb, Cd and Cu partially from non-local or diffuse sources (traffic, domestic heating, far transport). The results of this research could be used to evaluate the air pollution deposition models and for ecological impact estimations.     

基于图谱可视化的中国大气氮沉降研究态势分析

[目的]系统地探究近10a中国大气氮沉降研究态势,为今后的相关研究提供科学借鉴。[方法]基于科学计量学与信息可视化分析方法,借助Citespace软件,从文献中分析近10a中国大气氮沉降研究热点及趋势。[结果]近10a来,在氮沉降背景下,森林生态系统中凋落物分解与土壤微生物特征一直是研究热点;近5a草地生态系统的研究地区更加广泛,但较少涉及林下草地;碳氮循环相关研究多集中于温带及亚热带森林区,研究内容更加丰富,研究方法向大数据分析及模型建立方向发展;大气氮沉降通量观测以水域生态系统为主,近5a来较多地结合了非点源污染及示踪技术。[结论]近10a来,中国氮沉降领域各学科交叉性和系统性增强,研究内容和尺度不断扩大,研究方法和技术趋于多样化;草地生态系统及微生物群落特征、氮沉降与全球变化及人类活动耦合关系研究成为近年来关注的热点。     

Statistical Modeling of Phosphorus Dry Deposition Rates Measured in South Florida

Dry deposition may be a substantial source ofphosphorus (P) to the Florida Everglades. Drydeposition has been measured on a weekly basis in theregion since 1987, but a significant amount of thisdata is missing (about 34%) due to instrumentalfailures and sample contamination. This study developsa statistical model of the P dry depositiontime-series to estimate missing data. The model isbased on a multivariate stochastic time-series theory.Model parameters are calibrated using theexpectation-maximization algorithm which is efficientfor data sets with many gaps. The pooled mean andstandard deviation of the data before estimating themissing values was 88.4±85.7 μg P m^-2d^-1 and after estimating the missing values was87.8±82.4 μg P m^-2 d^-1. Modelverification demonstrates that the calibrated modelsprovide unbiased data estimates while preserving thestatistics of the raw data. For each sampling site themean and standard deviation before and after werequite similar. No trend with time was detected. The Pdeposition fluctuates seasonally (highest in Octoberand lowest in June), but this fluctuation does notfollow the seasonal pattern of Florida's rainfall. Random noise in the data, however, is significant andcauses long-term fluctuations of the data. The datawith gaps filled in are useful for computing theweekly P load distribution.     

Rapid Time Variations in Chemical Composition of Precipitation in South Korea

Data from a monitoring program on precipitation at four sites in South Korea during the period from 1993 to 1998 were analyzed for determining a time trend relationship in chemical composition of precipitation. The concentrations of nss-sulphate, ammonium and calcium were found to have decreased over time at a statistically significant level in Seoul (p<0.05). The concentration of nss-sulphate had declined by a rate of 12% per year for the period from 1993 to 1998. The concentrations of ammonium and calcium decreased by 11% and 12% per year respectively for the same period. The concurrent reduction of cation offsets the change in strong acid anion, thus the annual mean pH of precipitation has been approximately constant. In contrast to the rapid change of sulphate, the second most abundant anion, nitrate, showed no statistically significant decrease. As a result, the nitrate to nss-sulphate ratio (N/S ratio) has increased rapidly; the N/S ratio in precipitation has increased from less than 0.1 in 1985 to nearly 0.5 in 1998 at Seoul. In spite of the short monitoring period, a significant upward trend in the N/S ratio was also observed at all of the other sites suggesting that the nitrogen species contribute more to precipitation acidity throughout Korea.     

Acidification of Red Pine Forest Soil Due to Acidic Deposition in Chunchon, Korea

The effect of acidic deposition on the soil under red pine forest in Chunchon, Korea was investigated. Precipitation, stream water, and soil solution chemistry were monitored at the watershed from 1997 to 1998. Acidity of the open-bulk precipitation was often neutralized by large amounts of ammonia (NH₃) that might have originated from livestock farming and fertilization. Estimated elemental budget at the watershed showed a positive correlation between loss of base cations and proton (H⁺) production due to nitrogen transformation in soil (ΔH⁺ _NT: ([NH₄ ⁺]_in-[NH₄ ⁺]_out)- ([NO₃ ^?]_in-[NO₃ ^?]_out)). When ΔH⁺ _NT increased, concentrations of nitrate in soil solutions also increased. Consequently, pH values of soil solutions decreased, although ion exchange with base cations contributed to buffer reaction. Since acid buffering capacity of the red pine forest soil was small, it was concluded that the input of ammonium nitrogen enhanced nitrification in soil thus causing soil acidification represented by loss of base cations from the watershed.     

Evaluation of the Atmospheric Deposition in an Urban Region in South Brazil

The purpose of the present study is to analyse the chemical composition of bulk and wet atmospheric deposition samples in the Guaíba Hydrographic Basin (GHB), in south Brazil. Samples of bulk and wet deposition were analysed during a 1-year's period (January to December 2002) at three different stations, i.e., 8^° Distrito and CEASA stations in the city of Porto Alegre, and Charqueadas station, in Charqueadas city. Conductivity, pH, Cl^?, NO₃ ^?, F^?, SO₄ ^{2 ?}, Na⁺, K⁺, Mg^{2 +}, NH₄ ⁺ and Ca^{2 +} were determined. The pH presented an average value between 4.75 and 7.45. Enrichment factor was characterised based on groups of acid (pH < 5.65) and alkaline (pH > 5.65) samples. For most of the studied ions, EF in bulk deposition was higher in alkaline samples, while in wet deposition there was little difference between acid and alkaline samples. The Multivariate Analysis technique, i.e. the Canonical Correlation Analysis (CCA), determined relationships between the two different data set (chemical and meteorological), identified the source (anthropogenic or natural) of the studied variables.     

Segmenting Green Tea Consumers by Purchase Motivation in South Korea

Since the 1990s green tea consumption in South Korea has been gradually increasing because consumers consider green tea as beneficial to health. It is, therefore, necessary to know the factors influencing each motivational cluster according to sociodemographic characteristics. This study aims to obtain an empirical understanding of the green tea market by using a segmentation approach to provide better information for green tea marketers in Korea. A self-administered survey was obtained from 595 consumers in Seoul, Korea. Four distinct segments from cluster analysis were identified based on motivation: low motivated (18.0%), social seekers (35.7%), want-it-all (25.3%), and refreshment (21.0%). A multinomial logit regression analysis was used to identify the characteristics of consumers who are most likely to opt for a suitable motivation segment. Results indicated that the determinants of consumer motivation are age, occupation, price, company, and purchasing place.     

Estimation of the Maximum Critical Load for Sulfur in South Korea

The maximum critical load of sulfur and its exceedance by the sulfur deposition of 1994–1997 were mapped for South Korea with a spatial resolution of 11 × 14 km using the steady-state mass balance method. The Korean soil and geological maps were used as basis for the estimations of the critical alkalinity leaching and the weathering rate of base cations. The normalized difference vegetation index data obtained from the Advanced Very High Resolution Radiometer (AVHRR) together with the observed primary productivity of plants were used for the estimation of the critical uptake of base cations. Wet deposition of the non-sea-salt base cations was derived from measured base cation concentrations in precipitation, precipitation rate and air concentration of total suspended particulate while dry deposition of base cations was estimated using the inferential technique using scavenging ratios. The predominant ranges of base cation weathering, uptake and deposition were estimated to be of 200 – 600 eq ha^?1 yr^?1, 200 – 400 eq ha^?1 yr^?1 and 400 – 600 eq ha^?1 yr^?1, respectively. Critical alkalinity leaching was mainly in the range of 1000 – 2000 eq ha^?1 yr^?1 due to relatively high value of precipitation runoff. Exceedance of sulfur critical load was found at 40 % of the ecosystems considered mainly in the southeastern part of Korea, and about 60 % of Korea ecosystems were sustainable against sulfur acidity loadings.     

Mapping of Acid Deposition Effects and Calculation of Corrosion Costs on Zinc in China

Corrosion damage to materials including objects of cultural heritage due to acid deposition has been shown to cause large costs in several studies in Europe and in the United States. So far no similar extensive studies have been performed in developing countries. The World Bank has therefore initiated and financed a study of the corrosion costs in China based on available data in the literature and obtained through contacts and visits to several institutes and organisations in China. An initial assessment of the corrosion costs in China due to acidifying pollutants has been performed using a model originally developed and applied in Europe, which has been adapted to conditions in China. Here, the model is described using zinc as an example. In the calculation of corrosion costs it is assumed that the stock of materials at risk can be allocated to census data, which enables a separate calculation of the cost for each province in China. The significant differences in corrosion attack is illustrated for zinc with a corrosion map of China based on environmental data and a dose-response function adapted for Chinese conditions including the dry and wet acid deposition effects as separate terms.