The effect of “acid rain” and mineral fertilizers on the biometrical features of larix decidua mill. Seedlings

The purpose of the present experiment was to describe the influence of various mineral fertilizers on the development of Larix decidua Mill. seedlings subject to the influence of simulated acid rain of pH 2.5, 3.0, 3.5, 4.0, 4.5. The seedlings were fertilized every month (from April up to October), in order to counteract acid rain. The composition of the fertilizers was diversified in order to select an optimum variant. Fertilizer with NK applied to the needles (Florovit) and NPK applied to the soil (Fruktus 2) as well as dolomite lime applied to the soil. One row per set was left without fertilization as a control for each pH step of acid rain treatment. The analysis of biometric characteristics showed that a two-year period of investigations was too short to estimate effects on Larix decidua Mill. seedlings. It, however, indicated important trends. High correlations were found between particular growth parameters i.e. diameter of root neck, root mass, total mass of: seedlings, needles, main shoots, lateral shoots, ligneous parts, total overground parts. No strong correlations were observed between the above mentioned parameters and the total height of the seedlings. Among the different treatments the best development was achieved at pH 4.0, whereas the weakest development was observed at pH 2.5. The analysis showed a decrease in biometrical features along with an increase in acidity of acid rain solution. The first year of the experiment had the greatest influence upon the growth of Larix decidua Mill. seedlings. Significant improvement in growth, in relation to control plots, was achieved by using NK-fertilizers onto needles — the best results, and NPK onto soil. The best increment of the height of seedling was noticed at pH 3.5. In the second year of the experiment the effects of pH of acid rain and fertilization decreased — no significant effect on biometrical features was observed. Applaying NPK fertilizer onto soil showed a positive effect in relation to dolomite treatment. The best increment was noticed at pH 4.0.     

Acidification in the Rhizosphere of Rape Seedlings and in Bulk Soil by Nitrification and Ammonium Uptake

Ammonium salts used as fertilizers may cause soil acidification by two different processes: nitrification in soil and net release of protons from roots. Their influence on soil pH may vary depending on the distance from root surface. The aim of this study was to distinguish between these two processes. For this purpose rape seedlings were grown 10 d in a system which separated roots from soil by a fine-meshed screen. As a function of distance from the plane root layer formed on the screen, pH, titratable and exchangeable acidity and NO₃- and NH₄-nitrogen were determined. The soil, a luvisol from loess, was supplied with no N or (NH₄)₂SO₄ either with or without a nitrification inhibitor (DCD). The bulk soil pH remained unaffected when no N or 400 mg NH₄? N kg^?1 soil plus DCD was applied but it decreased from 6.6 to 5.8 without DCD. In contrast, rhizosphere pH decreased in all cases, mainly within a distance of 1 mm from the root plane only, but with gradients extending to between 2 and 4 mm into the soil. The strongest pH decrease, from 6.6 to 4.9, occurred at the root surface of plants treated with both NH₄-N and DCD where most of the mineral N remained as ammonium. In this case Al was solubilized in the rhizosphere as indicated by exchangeable acidity. Total soil acidity produced in the NH₄ treatment without DCD was mainly derived from nitrification compared to root released protons. However, acidification of the rhizosphere was diminished by nitrification because nitrate ions taken up by the roots counteracted net proton release. It is concluded that nitrification inhibitors may reduce proton input from ammonium fertilizers but enhance acidification at the soil-root interface which may cause Al toxicity to plants.     

Impacts of acid precipitation on coniferous forest ecosystems

This paper summarizes the results from current studies in Norway. One main approach is the application of artificial acid ‘rain’ and of lime to field plots and lysimeters. Application during two growth seasons of 50 mm mo^?1 of ‘rain water’ of pH 3 to a podzol soil increased the acidity of the humus and decreased the base saturation. The reduction in base saturation was mainly due to leaching of Ca and Mg. Laboratory experiments revealed that decomposition of pine needles was not affected by any acid ‘rain’ treatment of the field plots. Liming slightly retarded the decomposition. No nitrification occurred in unlimed soils (pH 4.4-4.1). Liming increased nitrification. The soil enchytraeid (Ohgochaeta) fauna was not much affected by the acidification. Germination of spruce seeds in acidified mineral soil was negatively affected when soil pH was 4.0 or lower. Seedling establishment was even more sensitive to increasing soil acidity. Analysis of throughfall and stemflow water in southernmost Norway reveals that the total deposition of H₂SO₄ beneath spruce and pine is approximately two times the deposition in open terrain. A large part of this increase is probably due to dry deposition. Increased acidity of the rain seems to increase the leaching of cations from the tree crowns. Tree-ring analysis of spruce (Picea abies (L.) Karst.) and pine (Pinus sylvestris L.) has been based on comparisons between regions differently stressed by acid precipitation and also between sites presumed to differ in sensitivity to acidification. No effect that can be related to acid precipitation has yet been detected on diameter growth.     

森林生态景观土壤酸化及修复技术研究

2010年在鼎湖山自然保护区,通过野外原位模拟酸雨控制实验和施用石灰、污水污泥和联合施用石灰＋污水污泥3种土壤酸化改良剂,研究了保护区内三种森林土壤在受到酸沉降影响后,土壤pH值和交换性Al3＋、H＋浓度的动态变化以及投加修复剂后混交林土壤酸度的变化情况。结果表明：三种森林土壤酸化严重（pH〈4.5）,pH值随处理酸度降低而下降;土壤交换性酸（H＋、Al3＋）含量随处理酸度降低而增加。酸沉降中H＋的输入,导致土壤铝被活化。三种改良剂的施用均可以缓解土壤酸化,降低土壤交换性酸（H＋、Al3＋）含量,从而降低植被铝中毒风险。三种修复技术中,联合施用石灰＋污水污泥修复技术效果最好。     

Soil acidification during more than 100 years under permanent grassland and woodland at Rothamsted

Abstract Soil samples have been taken periodically from unlimed plots of the 130-year-old Park Grass Experiment and from the 100-year-old Geescroft Wilderness at Rothamsted. Changes in the pH of the samples show how acidification has progressed. The soils are now at, or are approaching, equilibrium pH values which depend on the acidifying inputs and on the buffering capacities of the soils. We have calculated the contributions to soil acidification of natural sources of acidity in the soil, atmospheric deposition, crop growth and nutrient removal, and, where applicable, additions of fertilizers. The relative importance of each source of acidification has changed as the soils have become more acid. Acid rain (wet deposited acidity) is a negligible source, but total atmospheric deposition may comprise up to 30% of acidifying inputs at near neutral soil pH values and more as soil pH decreases. Excepting fertilizers, the greatest causes of soil acidification at or near neutral pH values are the natural inputs of H⁺ from the dissolution of CO₂ and subsequent dissociation of carbonic acid, and the mineralization of organic matter. Under grassland, single superphosphate and small amounts of sodium and magnesium sulphates have had no effect on soil pH, whilst potassium sulphate increased soil acidity slightly. All of these effects are greatly outweighed under grassland, however, by those of nitrogen fertilizers. Against a background of acidification from atmospheric, crop and natural inputs, nitrogen applied as ammonium sulphate decreased soil pH up to a maximum of 1.2 units at a rate in direct proportion to the amount added, and nitrogen applied as sodium nitrate increased soil pH by between 0.5 and 1 unit.     

Three-year growth responses of Pinus taeda L. to simulated rain chemistry,soil magnesium status,and ozone

Height, diameter, and biomass were measured for loblolly pine (Pinus taeda L) seedlings grown in soil containing 15 or 35 Μg Mg g^?1 and exposed from May to October in 1987, 1988, and 1989 to three O₃ concentrations (sub-ambient, ambient, or twice-ambient) and to rain pH levels of 3.8 or 5.2. Reduction in biomass accumulation in seedlings exposed to twice-ambient O₃ vs sub-ambient O₃ was 14% (P = 0.03) in 1987, 11.4% (P = 0.002) by 1988, and 8% (P = 0.15) by 1989. The greatest height growth occurred in seedlings exposed to twice-ambient O₃, and the greatest stem diameter growth occurred in seedlings exposed to sub-ambient O₃. A comparison of stem volume (d²h) with stem biomass suggested that tissue density was reduced by elevated O₃. Biomass accumulation response to rainfall chemistry was small (5.5% reduction in the low pH treatment in 1989) and not statistically significant for most plant tissues. Growth response to soil Mg status was not significant. Hoewever, in 1989 treatment interactions between rainfall chemistry and soil Mg status were observed. Height was 5% greater (P = 0.02) and biomass was 6% greater (P = 0.10) in seedlings grown in higher-Mg soil and receiving higher-pH rainfall than seedlings grown in any of the other pH-Mg treatment combinations. The data suggest direct adverse effects of near ambient O₃ and indirect, slower acting and interacting adverse effects of rainfall chemistry and soil nutrient status on growth of loblolly pine.     

模拟酸雨对茶园土壤中铅的溶出及形态转化的影响

采用模拟酸雨连续淋洗的方法,研究了茶园土壤的酸化以及不同铅污染程度土壤中铅的溶出和形态转化规律。结果表明,土壤的酸化程度受酸雨酸性强度的控制,酸雨pH越低,土壤酸化程度越强;土壤中铅的溶出总量随模拟酸雨的酸度和土壤本身含铅量的增加而增加,但是土壤滤液中铅含量随时间变化的规律只受模拟酸雨的pH影响;土壤铅污染程度越严重,其中的活性态铅含量越高,同时pH<4.5的酸雨会使土壤中的非活性态铅大量向活性态转化,这将导致土壤中铅的活化而增加其生态风险。     

Lysimeter Study on the Effects of Different Rain Qualities on Element Fluxes from Shallow Mountain Soils in Southern Norway

This study focuses on fluxes of elements from, and changes in the soil properties of shallow organic material rich soil as a result of changes in precipitation acidity. Intact soil columns including natural vegetation from two areas (one exposed to acidic precipitation and one unpolluted) were used in a lysimeter experiment. The lysimeters were watered with simulated normal rain (pH 5.3) or simulated acidic rain (pH 4.3) for four years. Sulphuric acid and ammonium nitrate were used to regulate the quality of the simulated rain. Significantly more SO₄ ^2? was leached from lysimeters receiving acid rain. Rain acidity had no significant effect on NO₃ ^? leaching. Significantly more Mg²⁺ was leached from lysimeters receiving acid rain, but this only applied for the soils from the unpolluted area. Four years of treatment did not cause any significant effect on the soil acidity and the amounts of base cations in the soil. The more acidic rain did, however, cause a significant lower cation exchange capacity. For the soils from the polluted area the acid precipitation did cause a lowering of the exchangeable K⁺ in the upper 5 cm of the soil. Different quality of the soil organic material indicated by different vegetation types appeared to cause significant differences in the amount of components leached from the soil, but did not cause any difference in response to the different rain qualities.     

Effects of Ozone and/or Soil Water Stress on Growth and Photosynthesis of Fagaus Crenata Seedlings

The effects of ozone (O₃) and soil water stress, singly and in combination, on the growth and photosynthesis of Fagus crenata seedlings were investigated. Four-year-old seedlings were exposed to charcoal-filtered air (< 5 nmol mol^?1 O₃) or 60 nmol mol^?1 O₃, 7 hours per day (11:00–18:00), for 156 days from 10 May to 11 October 1999 in naturally-lit growth chambers at 20/15 °C (6:00–18:00/18:00–6:00). During the same period, half of the seedlings in each gas treatment received 250 mL of water at the 3-day intervals (well-watered treatment), while the rest received 175 mL of water at the 3-day intervals (water-stressed treatment). The exposure of the seedlings to O₃ caused reductions in the leaf, stem, root and whole-plant dry weights. The net photosynthetic rate at 350 µmol mol^?1 CO₂, the maximum net photosynthetic rate at saturated CO₂-concentration, carboxylation efficiency of photosynthesis and Rubisco content were significantly reduced by the exposure to O₃. The soil water stress induced reductions in the stem, bud and whole-plant dry weights, transpiration rate and leaf water potential during the midday. The additive effects of O₃ and soil water stress were observed on the dry matter production, leaf gas exchange rates and leaf water potential. As a result, the whole-plant dry weight of the seedlings exposed to both stresses was markedly reduced compared with that of the seedlings exposed to charcoal-filtered air and grown in the well-watered treatment.     

Growth and gas exchange of loblolly pine seedlings as influenced by drought and air pollutants

One-year-old loblolly pine seedlings were exposed to 0₃(≤0.025 or 0.10 μ L L^?1, 4 hr d^?1, 3 d wk^?1) in combination with simulated rain (pH 5.6 or 3.0, 1 hr d^?1, 2 d wk^?1, 0.75 cm hr^?1) for 10 wk. After the 10-wk treatment, the seedlings were submitted to two drought cycles, and water potential, net photosynthesis (Pn), and transpiration (Tr) were measured. Whole-plant fresh weight increment and relative growth rate were significantly increased in seedlings exposed to simulated rain at pH 3.0 compared to pH 5.6. An interaction between 0₃ and simulated rain occurred in height growth. Shoot height elongation was significantly less in seedlings exposed to 0.10 μL L^?1 0₃ + pH 5.6 than in any other pollutant combination after the 10-wk treatment period. There were no significant effects of 0₃ on Pn and Tr prior to the drought cycles; however, after the first drought cycle, Pn was significantly higher in seedlings pre-exposed to 0.10 μL L^?1 0₃ compared to the low 0₃ concentration. The 10-wk treatment with simulated rain at pH 3.0 significantly increased Pn and Tr. The relationship between gas exchange rates and needle water potential during the moisture stress period was affected by preexposure to pollutants. In general, Pn and Tr were more sensitive to decreasing needle water potential in seedlings exposed to pH 3.0 during the first drought cycle and to 0.10 μL L^?1 0₃ during second drought cycle.     

Effects of acidification and liming on carbon and nitrogen mineralization and soil organisms in mor humus

The aim was to determine if changes in C and N mineralization after acidification and liming could be explained by changes in the soil organism biomass. Intact soil cores from F/H layers in a Norway spruce (C:N=31) and a Scots pine (C:N=44) stand in central Sweden were treated in the laboratory for 55 days with deionized water (control), weak H₂SO₄ (successively applied as 72 mm of acid rain of pH 3.1), strong H₂SO₄ (applied as a single high dose of pH 1), and lime CaCO₃. Strong acidification reduced C mineralization and increased net N mineralization in both soils. Weak acidification resulted in similar but less pronounced effects. Liming initially stimulated C mineralization rate, but the rates declined, indicating that an easily available C source was successively used up by the microorganisms. Liming also increased net N mineralization in the C:N=31 humus, but not significantly in the C:N--44 humus. Strong acidification generally affected the amounts of FDA-active fungal hyphae, nematodes and enchytraeids more than the other treatments did. The increases in net N mineralization after acidification and liming could only partly be explained by the decreases in biomass N in soil organisms. Mineralization of biomass N from killed soil organisms could at the most explain up to about 30% of the increase in net N mineralization after strong acidification. Most of the effects on N mineralization seemed to depend on the fact that acidification reduced and liming increased the availability of C and N to the microorganisms. Furthermore, acidification seemed to reduce the incorporation of N from dead organisms into the soil organic matter and, thereby, make the N compounds more readily available to microbial decomposition and mineralization.     

Short-term effects of a simulated acid rain upon the growth and nutrient relations of Pinus strobus,L.

Acidified precipitation may affect the productivity of forests by altering the availability of plant nutrients or by affecting the ability of trees to absorb and assimilate those nutrients. In this study, the short-term effects of simulated acid rain (pH range 5.6 to 2.3) upon the growth and nutrient relations of Eastern White Pine seedlings (Pinus strobus, L.) grown in a sandy loam soil were examined. Soil chemistry, soil leachate chemistry, seedling tissue chemistry, and seedling productivity were monitored. Inspite increased leaching of cations from the soil, resulting in near depletion of available K⁺¹, Mg⁺², and Ca⁺¹ at pH 2.3, seedling productivity increased with acidity through the 20-week experimental period. Foliar nitrogen concentrations indicate that fertilization with NO ₃ ^?1, added to the rain as HNO₃, may have caused the growth increase. Implications of cation losses and NO₃ ^?1 fertilization are discussed.     

Effects of simulated acid rain on the growth,nutrition, foliar pigments and photosynthetic rates of sugar maple and white spruce seedlings

Sugar maple (Acer saccharum Marsh.) and white spruce (Picea glauca (Moench) Voss) seedlings were exposed to simulated acid rain (SAR) of pH 3.2, 4.3 and 5.6 for two and one-half growing seasons. Ambient rain was excluded from the treatment plots by mobile rain exclusion canopies. Sugar maple seedlings treated with pH 3.2 SAR had significantly higher foliar concentrations of nitrogen, sulphur and manganese, compared to either the pH 4.3 or 5.6 treated seedlings. The pH 3.2 treated seedlings also tended to have greater growth and photosynthetic rates compared to the pH 4.3 and 5.6 treated seedlings. In contrast, the pH 3.2 treated white spruce seedlings tended to have decreased growth and lower foliar potassium concentrations relative to the pH 4.3 and 5.6 treated seedlings. Statistically there were no significant treatment differences in seedling height, seedling diameter, foliar pigments, or photosynthetic rates in either the sugar maple or white spruce seedlings.     

A two-year experience on 15N-urea fertilization of a corn field amended with fly ash

Soybean seedlings (Glycine max) were exposed to simulated acid rain containing sulfate ion only or a mixture of sulfate, nitrate and chloride anions, using a continuous rain generating system in a side opened glasshouse. Plants were subjected to acid rain treatment twice a week, for a 1 or 3 hr period at a rate of 2.2 or 5.0 mm hr^?1, respectively. Dry seed yield in plants treated with simulated acid rain at pH 2.0, in the three of 4 experiments conducted over a 3 yr period, was significantly less than that at pH 3.0 or higher. Simulated acid rain treatment at pH 3.0 or higher did not significantly affect yield compared to pH 5.6; however, plants exposed to simulated acid rain at pH 4.0 tended to yield more than those treated with pH 5.6 rain. Based on the current 3 years of research in which results from 4 experiments were combined, rain acidity at current levels in Japan would not directly affect seed production of selected cultivars of soybean.     

电渗析与酸淋洗模拟紫色土酸化的效果比较

为了比较电渗析与酸淋洗试验模拟紫色土酸化的效果,在重庆地区采集了不同pH(5.00和7.06)的2个紫色土,分别进行不同天数(1,2,5,7,10天)的电渗析和酸淋洗试验处理,并分析了试验处理前后土壤的酸度特征和交换性盐基成分含量变化。结果表明,在整个10天的淋溶处理过程中,2种紫色土的pH均无显著变化,说明紫色土具有一定的酸缓冲能力,短期的酸雨淋溶不能实现紫色土的严重酸化。而采用电渗析处理10天后,中性紫色土和酸性紫色土的pH分别降低3.4和1.1个单位。在整个电渗析处理过程中,土壤的交换性酸含量显著升高,盐基离子大量淋失。电渗析可以实现对紫色土的快速酸化处理。2种紫色土中,电渗析处理后中性紫色土的酸化程度大于酸性紫色土。这是由于中性紫色土的表面负电荷量更高,导致更多致酸离子吸附在土壤胶体表面,最终造成中性紫色土的酸化程度更加严重。因此,电渗析处理比酸雨淋溶处理对紫色土酸化效果更好,且可用于紫色土的酸化机理研究。进一步结合2种方法的技术可操作性,认为电渗析法是研究紫色土酸化问题的一种有效技术手段。     

Project rain: Changing acid deposition to whole catchments. The first year of treatment

Project Rain (Reversing Acidification In Norway) is a 5-yr international research project aimed at investigating the effect on water and soil chemistry of changing acid deposition to whole catchments. The project comprises 2 parallel large-scale experimental manipulations -- artificial acidification at Sogndal and exclusion of acid rain at Risdalsheia. Treatment at Sogndal commenced April 1984 with the acidification of the snowpack by addition of H₂SO₄ (SOG2) and a 1:1 mixture of H₂SO₄ and HNO₃ (SOG4). Preliminary results indicate rapid and significant response in runoff chemistry to the acid treatment; pH decreased (to as low as 4.1 during snowmelt in 1984); SO₄, NO₃, and labile Al increased. Response during snowmelt 1985 was modest relative to 1984. At Risdalsheia treatment began in June 1984 with the mounting of the transparent panels on the roofs at KIM catchment (treatment by deacidified rain) and EGIL catchment (control with ambient acid rain). Preliminary data for the first year indicate that most runoff samples from KIM contain much lower NO₃ concentrations, about 20 to 30% lower SO₄ levels and pH 0.1 to 0.3 units higher than runoff from EGIL catchment. The treatments continue in 1985–87. Project RAIN provides experimental evidence bearing on target loading, reversibility of acidification, and the processes linking acid deposition, soil acidification and freshwater acidification.     

The individual and combined effects of ozone and simulated acid rain on chlorophyll contents,carbon allocation and biomass accumulation of armand pine seedlings

The seedlings of armand pine (Pinus armand Franch.) were applied to exposure, alone or in combination, to charcoal filtered air (CF) or ozone (O₃) at 300±15 nl/l(ppb) for 8 h a day, 6 days a week, and simulated rain of pH 6.8, 3.0 or 2.3, six times a week, alone and in combination, for 14 weeks from June 15 to September 20, 1993. No significant interactive effects of O₃ and simulated acid rain were observed on chlorophyll contents, carbon allocation and biomass accumulation of the seedlings in the present study. The O₃ caused reductions in biomass accumulation of whole-plant and below-ground parts, but not that of above-ground parts without an acute visible foliar injury. At the same time, the O₃ reduced R/S ratio, but raised F/C ratio. Therefore, O₃ also altered carbon allocation pattern. On the other hand, chlorophyll contents were increased by simulated acid rain, but other determined parameters were not altered.     

Effect of simulated acid rain on the growth of soybean

Soybean seedlings (Glycine max) grown in a glasshouse were exposed to simulated acid rain using a solution of deionized water containing sulfate, nitrate and chloride in concentrations and proportions equivalent to those in ambient rain water. Plants were subjected to acid rain treatment twice a week during the growing season, for a 1 hr period at a rate of 5 mm hr^?1. When the acid rain was below pH 3.0, visible symptoms developed in the young trifoliate leaves. However, at a pH above 3.0 there was no evidence of visible leaf injury; also tissue dry weights and leaf areas were not affected even after 7 weeks of exposure. The number of root nodules in plants exposed to acid rain at pH 4.0 tended to be higher than those of control plants maintained at pH 5.6, but decreased subsequently with decreasing pH. Based on our results current ambient levels of rain acidity in Japan should not have an adverse impact on seedling growth in soybean.     

Effects of artificial acidification and liming on the activity of digestive enzymes in Cognettia sphagnetorum (Vejdovsky´, 1878) (Annelida, Enchytraeidae)

The effects of simulated acid rain and acidification, combined with liming, on amylolytic, laminarinolytic and xylanolytic activity in whole body homogenates of enchytraeids Cognettia sphagnetorum were studied under field conditions. Simulated acid rain (pH 2.5) and simulated acid rain with subsequent liming (CaCO₃) were applied to experimental plots in a mixed forest soil. The pH of the soil was lowered by acid treatment (4.3), while the pH increased after liming (6.3) in comparison with the control (4.5). Acidification of soil caused a decrease in enchytraeid body mass and amylolytic activity. In acidified plots after liming, amylolytic activity and laminarinolytic activity increased, while live body mass decreased. The enzymatic activity of enchytraeids depended on season and also indirectly on individual mean mass. Received: 12 February 1996     

Lysimeter study with a cambic arenosol exposed to artificial acid rain: II. Input-output budgets and soil chemical properties

The effects of artificial precipitation with different pH levels on soil chemical properties and element flux were studied in a lysimeter experiment. Cambic Arenosol (Typic Udipsamment) in monolith lysimeters was treated for 6 1/2 yr with 125 mm yr^?1 artificial rain in addition to natural precipitation. Artificial acid rain was produced from groundwater with H₂SO₄ added. pH levels of 6.1, 4 and 3 were used. ‘Rain’ acidity was buffered, mainly due to cation exchange with Ca²⁺ and Mg²⁺, which were increasingly leached due to the acid input. The H⁺ retention was not accompanied by a similar increase in the output of Al ions, but a slight increase in the leaching of Al ions was observed in the most acidic treatment. The net flux of SO₄ ^2? from the lysimeters increased with increasing input of H₂SO₄, but in the most acidified lysimeters significant sorption of SO₄ ^2? was observed. The sorption was, however, most likely a concentration effect. The ‘long-term’ acidification effects on soil were mainly seen in the upper O and Ah-horizons, where an impoverishment of exchangeable Ca²⁺ and Mg²⁺ was observed. An increased proportion of Al ions on exchange sites in the organic layer was observed in the pH 3-treated soil. By means of budget calculations the annual release of base cations due to weathering was estimated to be between 33 and 77 mmol_c m^?2.