A Dendrochemical Survey of Sugar Maple (Acer saccharum Marsh) in South-Central Ontario,Canada

A dendrochemical survey of sugar maple (Acer saccharum Marsh) was conducted insouth-central Ontario, which encompassed twenty-two sites in areas that both exceeded orwere below the published Critical Loads with respect to acid deposition. Areas thatexceeded the Critical Load were located remote from point emission sources, but were alsocharacterized by thin, nutrient-poor soils overlying the Precambrian Shield. ThepH_aq of surface soils (A-horizon) was lower at sites on the Precambrian Shield andwater-extractable concentrations of Ca decreased exponentially with decreasing soil pH. Significant polynomial relationships between soil pH and soil Ca and sugar maple growth,assessed as cumulative tree-ring growth between 1949 and 1998, explained 40% and 37% ofthe variation in sugar maple growth respectively, with lowest growth associated with lowsoil pH and low soil Ca. Furthermore, there was a significant linearrelationship between wood Ca concentrations (averaged between 1949 and 1998) and soil pHand concentrations of several trace elements in wood (Mn, Pb, Zn, Cd, Sr and Rb) were greater atlow soil pH. Poor sugar maple growth was associated with low wood Ca concentrations andhigh wood Al levels, which together accounted for 43% of the variation in sugar maplegrowth in a multiple regression model. None of the other wood chemistry variablescontributed significantly to the model. These data suggest that sugar maple grows poorlyon acidic soils with low Ca and high Al levels. Although such acidic podzols occurnaturally in some areas overlying the Precambrian Shield, if Ca losses due to aciddeposition and/or harvesting exceed inputs through weathering and deposition(i.e. exceed Critical Load), sugar maple growth may be adversely affected and ultimately lead toincreased incidence of sugar maple decline.     

The Impact of Simulated Acid Rain on Soil Leachate and Xylem Chemistry in a Jack Pine (Pinus Banksiana Lamb.) Stand in Northern Ontario,Canada

The impact of simulated acid rain on soil leachate and xylem chemistry in a young Jack pine (Pinus banksiana Lamb.) stand in the boreal forest of northern Ontario was evaluated. Permanent plots (5 × 2 m) were established in 1981 which were sprayed twice monthly with simulated acid rain, adjusted to pH 5.6, 4.0, 3.5, 3.0 or 2.5 with a 2:1 molar ratio of sulphuric (H2SO4) to nitric acid (HNO3) in addition to ambient rainfall. Sprays were applied between June and September for 5 yr. Unsprayed plots were also monitored. The pH of soil leachate collected between 1981–1985 was reduced significantly by the acid sprays and concentrations of sulphate (SO42-), nitrate (NO3-), calcium (Ca), magnesium (Mg), aluminium (Al), manganese (Mn), and zinc (Zn) increased in the A, B and C horizons. The soil recovered rapidly from the spray treatments, although residual effects were found in soil leachate samples collected during 1986–1987, particularly in the C horizon. Trees receiving spray acidified to pH 2.5 had higher concentrations of Ca, Mn, Cd and Rb in tree-rings formed between 1981–1985 compared to trees receiving spray acidified to pH 4.0 or to trees receiving ambient rainfall alone. Some of the changes in soil chemistry resulting from the application of acidic sprays are reflected in the chemistry of Jack pine tree rings and these chemical signals in tree rings may be used as indicators of soil acidification.     

Impact of Simulated Acid Rain on Growth and Yield of Two Cultivars of Wheat

The present study reports the results of a field-basedexperiment conducted to assess the effect of simulated acid rain(SAR) of different pH i.e. 5.6 (control), 5.0, 4.5, 4.0 and 3.0on two cultivars of wheat (Triticum aestivum, Malviya 213(M213) and Sonalika). Shoot and root lengths significantlydeclined at pH 3.0 in both varieties. Leaf area declined at pH4.0 and 3.0 in M213 at both ages and at 75 days in Sonalika.Total biomass of 75 days plants declined significantly at pH range4.5–3.0 in M213 and at pH 4.0 and 3.0 in Sonalika. Netassimilation rate (NAR) declined significantly at pH 3.0 inboth varieties. Compared to control, yield of M213 showedsignificant reductions at pH 4.0 and 3.0, whereas Sonalikaresponded negatively at pH 3.0. The study showed that acid rainhas a significant negative effect on wheat plant performance.     

模拟酸雨对施肥条件下赤红壤氮磷淋失特征的影响

通过土柱模拟淋洗试验,研究了施用等量有机复合肥条件下,不同酸度模拟酸雨对赤红壤氮磷淋失特征的影响。结果表明,铵态氮、硝态氮、无机氮和总氮淋失量均随酸雨pH值增大而下降;pH 2.0模拟酸雨和对照(pH 6.5)的无机氮和总氮淋失量差异不显著,但均显著高于pH 3.0、pH 4.0和pH 5.0酸雨;pH 5.0模拟酸雨无机氮和总氮淋失量均最低,表明强酸性酸雨和中性淋洗液均促进氮淋失,而酸度与土壤接近的酸雨减少氮淋失。与对照相比,模拟酸雨对DP淋失无显著影响,但显著降低PP和TP淋失;不同模拟酸雨各形态磷淋失量均无显著差异,表明酸雨对赤红壤磷淋失影响有限。酸雨对淋滤液氮磷浓度动态变化和氮磷累计淋失量动态变化等均无显著影响。     

Effects of Simulated Acid Rain on the Antioxidative System in Cinnamomum philippinense Seedlings

This study examined the importance of the antioxidative defense mechanism during the application of simulated acid rain (SAR) pH 4, pH 3, pH 2, and pH 6 as control treatment in Cinnamomum philippinense seedlings. Analysis was carried out on 1, 10, and 15 days of spraying SAR. In our results, catalase (CAT), ascorbate peroxidase (APx), guaiacol peroxidase (GPOD), and glutathione reductase (GR) activity significantly were induced on 1 day of spraying SAR pH 3 and pH 2, suggesting that C. philippinense seedlings exposed to pH 3 and pH 2 acid rain for only 1 day were under oxidative stress, and antioxidant enzyme were apparently increased until 10 days of spraying SAR pH 4. However, on 10 days of spraying SAR pH 2, the accumulated intensity of acidity significantly inhibited the activities of CAT and APx accompanying with increased concentrations of malonydialdehyde (MDA). On the contrary, GPOD activity and the ascorbic acid ratio were remarkably increased when spraying SAR pH 2 for 15 days. Therefore, GPOD and ascorbate contribute to the scavenging of ROS at stronger acidity stresses. However, they were not enough to avoid cellular damage, since membrane lipids were injured, and necrosis appeared.     

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。     

模拟酸雨对荔枝果园土壤磷素等温吸附与解吸特性的影响

采用等温吸附试验方法研究了模拟酸雨对荔枝果园土壤磷的吸附与解吸特性的影响。试验结果表明,不同处理间土壤对磷的最大吸附量(Xm)为pH2.5>pH4.5>CK=pH6.5,其中pH2.5的酸雨淋溶处理对磷的最大吸附量(Xm)与其它处理间差异显著;土壤吸附磷的解吸量(Xd)分别与相应的吸附量(X)和原平衡溶液浓度(C)呈显著的指数相关和线性相关,随着土壤对吸附量的增加,土壤磷的解吸量呈指数增长。     

模拟酸雨条件下海泡石对污染红壤镉、铅淋溶的影响

采用填充土柱淋溶试验研究不同pH值模拟酸雨和海泡石添加量对重金属污染红壤Cd、Pb淋溶的影响.结果表明,Cd在酸雨pH值较低时累积淋溶量较大,Pb的累积淋溶量随酸雨pH值的降低逐渐增加,pH值为3.5处理的Pb总累积淋溶量显著高于其他pH值处理(高出54.9％).与对照相比,模拟酸雨pH值为3.5时,添加5 g/kg和10 g/kg海泡石处理Cd的总累积淋溶量明显增加(分别增加24.6％和26.3％),而Pb的总累积淋溶量分别显著降低34.7％和25.7％;酸雨pH值为4.5时,添加5 g/kg和10g/kg海泡石处理降低了Cd的累积淋溶量(分别降低13.0％和1.4％),而Pb的淋溶量随海泡石添加量的增加而降低,10 g/kg海泡石处理的Pb总累积淋溶量显著下降17.6％;pH值为5.5和6.5时,海泡石处理Cd累积淋溶量均有所下降,而对Pb的淋溶无显著降低效果.酸雨酸性强度的增大增加了Cd、Pb的淋溶风险,且Pb比Cd敏感.添加海泡石可有效减少酸雨对土壤中Pb的淋溶,但其对Cd淋溶的影响受酸雨酸性强度的影响.     

模拟酸雨对不同园林植物叶片生理生态特性的影响

采用盆栽方法,以自来水（pH值6.5）作为对照,研究了pH值为1.7,3.0,4.3,5.6模拟酸雨条件下新梢增长量、叶片损伤程度和叶片生理生态特性,并分析了园林植物对酸雨污染的敏感性反应。结果表明:不同pH值的酸雨对园林植物新叶片有不同程度的抑制,酸雨的酸度越大,对园林植物叶片的伤害越大,以pH值1.7的模拟酸雨对园林植物叶片的伤害最为严重,pH值5.6伤害较为轻微,但不同种类之间对酸雨的抗性有明显差异;pH值4.3~5.6处理对园林植物新梢生长率没有显著的影响和抑制作用,而pH值小于3.0处理则严重抑制了园林植物新梢生长;随模拟酸雨强度的增强,园林植物叶片的细胞质膜透性和丙二醛（MDA）含量逐渐升高,当pH值小于3.0时,细胞质膜透性和丙二醛（MDA）含量则急剧增加,当pH值为1.7时,不同园林植物叶片则严重受损;园林植物叶片叶绿素含量、叶片N和P含量随酸雨强度的增加逐渐降低,当pH值小于3.0时,园林植物叶片叶绿素含量、叶片N和P含量则急剧降低,当pH值为1.7时,不同园林植物叶片则严重受损;相关分析表明,酸雨增加了园林植物对环境的敏感性。园林植物对酸雨具有较强的抵抗能力,对园林植物生理活动影响的阈值pH值大致介于3.0~4.3,因此,本研究的6种园林植物可以作为酸雨灾害严重地区园林绿化及植被构建的物种。     

酸雨对紫色土中镉、锌形态及植物有效性的影响

研究了在锅、锌单一污染及镉、锌复合污染的紫色土中,酸雨对镉、锌的形态及植物有效性的影响.结果表明,酸雨胁迫下复合镉、锌对作物的危害明显加重.酸雨胁迫不但改变了紫色土中可交换态镉、锌含量,而且使紫色土中镉、锌各形态(可交换态、碳酸盐结合态和氧化锰结合态)发生相互转化.采用通径分析也表明,酸雨使各形态对植株镉、锌累积量的贡献系数发生改变,直接影响其植物有效性.镉、锌复合处理与镉单一处理相比较,低浓度锌可促进莴笋对镉的吸收,提高了镉的植物有效性,而高浓度锌时则相反.     

The Impact of Acid Rain on Potassium and Sodium Status in Typical Soils of the Wielkopolski National Park (Poland)

A previous investigation of thechemical characteristics of precipitation in theWielkopolski National Park has shown its high acidity,which sometimes drops below pH 3.0. This paper dealswith the leaching of potassium and sodium ions by acidrain from typical soils of the study area. Laboratoryexperiments were conducted on undisturbed soil cores(15 cm in diameter, 50 cm high) with acid solutions of pH 3.0, pH 2.0 and with water of pH 5.6 (control). The sprinkling lasted 30 days simulating a rainfall of 400 mm. The eluates were analysed daily. Soil propertiesand forms of potassium and sodium were determinedbefore and after treatment. The investigations showthat quite significant amounts of K⁺ andNa⁺ can be leached from the soil: in the very acidtreatment (pH 2.0) about 4 mg K⁺ and 3 mgNa⁺ per kg of soil. The leaching of these elementswas smaller in the pH 3.0 and 5.6 treatments.Differences in the dynamics of the process are shownin the leaching curves. In the case of potassium theirshapes are smooth when pH is 5.6 and 3.0, while at pH2.0 the curves rise sharply. The leaching curves inthe case of sodium do not show sharp peaks, whichmeans that the leaching is slow and equalised.     

模拟条件下生物腐殖酸肥对土壤磷素淋失及流失的影响

通过模拟淋溶和径流实验,考察单施生物腐殖酸肥(BHA)后磷在竖直及水平方向的迁移能力,并通过室外小白菜种植实验进一步开展淋溶和径流中磷的行为研究,考察单施BHA对小白菜长势、产量的影响及对受纳水体水质的污染风险。实验以施化肥(CF)和不施肥(NOP)为对照。结果表明,(1)在模拟淋溶及径流实验中,经过8次浇水,BHA处理组的淋溶液及径流液中TP含量的最高值及平均值均高于CF及NOP处理组,在磷淋失量及淋失率上,3个处理间均无显著差异;在磷流失量及流失率上,BHA与CF无显著差异,二者均显著高于NOP处理组,其磷流失量分别比NOP高208.96%、147.01%,流失率分别比NOP高1.98%、1.39%。(2)室外小白菜种植的淋溶及径流实验中,在对小白菜长势的影响方面,BHA与CF无显著差异,二者均显著高于NOP处理组;在对小白菜产量及植株吸磷量的影响方面,CF处理组显著高于BHA及NOP。在磷淋失量上,BHA与CF无显著差异,二者均显著高于NOP处理组;在磷流失量上,BHA处理组显著高于CF及NOP,分别高78.52%、82.48%。研究表明,尽管BHA中的磷不如CF易被小白菜吸收利用,但是二者对小白菜长势的影响无显著差异;BHA施用后磷更易随径流液流失,而不易随淋溶液淋失,因此,施用BHA后应避免立即灌溉,尤其是大水漫灌。     

Impact of the Textile Dye Acid Blue 40 on the Periphyton of a Simulated Microecosystem

Textile industry is responsible for a large amount of wastewater inappropriate for both human consumption and aquatic species. Aquatic ecosystems are way more sensitive to the release of textile wastewater, and the usage of Winogradsky columns is interesting, once they are a simulated aquatic ecosystem in which the growth of algae and other microorganisms can be observed. In this research, simulated textile effluents with the dye Acid Blue 40 were treated with an electrolytic reactor, for a later ecotoxicological evaluation using Winogradsky columns. The algal and microbial population and primary production were measured. The results have shown that the electrolytic treatment was satisfactory when it comes to color removal, but the presence of the treated effluent in the Winogradsky columns changed the microecosystem. The number of algae identified decreased when exposed to certain effluents, and some algae groups even disappeared, while others such as Cyanophyceae were benefited.     

模拟酸雨条件下改性沸石对污染土Pb、Zn的淋溶效应

通过室内模拟土柱淋溶实验,研究了不同pH值(3.1,4.1,6.5)的酸雨下,改性沸石用于控制污染土重金属Pb、Zn的淋溶效果。结果表明,淋溶过程中,酸雨pH值越小,改性沸石剂量越高,淋滤液的pH值相对越大,且酸雨pH值的降低并没有引起Pb、Zn淋溶总量的显著增加;不同pH和不同剂量改性沸石下,Pb的淋溶总量要明显大于Zn的淋溶总量;相比于空白剂量(0g/kg)沸石,高剂量(100g/kg)改性沸石和低剂量(20g/kg)改性沸石均能显著降低Pb和Zn的淋溶总量,且两者所起效果相差不大,其中,酸雨pH值为3.1,4.1和6.5时,对添加低剂量沸石,Pb的淋溶总量分别降低28.7%,34.8%和40%,而Zn的淋溶总量分别降低48.5%,53.9%和45.5%。研究结果表明,天然沸石经过一定方法改性后,可以有效防止酸雨条件下污染土壤重金属Pb和Zn的淋溶流失。     

Impact of Tillage and Fertilizer Application Method on Gas Emissions in a Corn Cropping System

Tillage and fertilization practices used in row crop production are thought to alter greenhouse gas emissions from soil.This study was conducted to determine the impact of fertilizer sources,land management practices,and fertilizer placement methods on greenhouse gas(CO₂,CH₄,and N₂O)emissions.A new prototype implement developed for applying poultry litter in subsurface bands in the soil was used in this study.The field site was located at the Sand Mountain Research and Extension Center in the Appalachian Plateau region of northeast Alabama,USA,on a Hartsells fine sandy loam(fine-loamy,siliceous,subactive,thermic Typic Hapludults).Measurements of carbon dioxide(CO₂),methane(CH₄),and nitrous oxide(N₂O)emissions followed GRACEnet (greenhouse gas reduction through agricultural carbon enhancement network)protocols to assess the effects of different tillage(conventional vs.no-tillage)and fertilizer placement(subsurface banding vs.surface application)practices in a corn(Zea mays L.)cropping system.Fertilizer sources were urea-ammonium nitrate(UAN),ammonium nitrate(AN)and poultry litter(M)applied at a rate of 170 kg ha^-1 of available N.Banding of fertilizer resulted in the greatest concentration of gaseous loss(CO₂ and N₂O)compared to surface applications of fertilizer.Fertilizer banding increased CO₂ and N₂O loss on various sampling days throughout the season with poultry litter banding emitting more gas than UAN banding.Conventional tillage practices also resulted in a higher concentration of CO₂ and N₂O loss when evaluating tillage by sampling day.Throughout the course of this study,CH4 flux was not affected by tillage,fertilizer source,or fertilizer placement method.These results suggest that poultry litter use and banding practices have the potential to increase greenhouse gas emissions.     

模拟酸雨对水稻、玉米和绿豆萌发及生长影响

通过模拟试验研究酸雨对水稻,玉米和绿豆的萌发及生长的影响,结果表明,ｐＨ２．０的模拟本雨明显降低作物的发芽率,伤害植物叶片,造成叶片细胞膜透性增加,使叶绿素含量,通过氧化氢酶和脱氢酶活性降低,ｐＨ３．０以上模拟酸雨短期内对作物无明显影响。     

BP神经网络模型在广西原料蔗产量预报中的应用

将广西甘蔗种植区气象台站的光温水资料采用膨化处理后按旬依次组合成不同时段值,通过相关分析方法普查选出与广西原料蔗产量相关系数通过0．01水平显著性检验的因子作为预报因子,分别用逐步回归方法和误差反传前向网络（BP神经网络）建立广西原料蔗产量预报模型,模拟结果对比分析显示,BP神经网络预报模型的拟合精度和预报精度均高于逐步回归模型。     

Ammonium Nitrogen Deposition as a Dominant Source of Nitrogen in a Forested Watershed Experiencing Acid Rain in Central Japan

To clarify nitrogen (N) sources, the overall N budget in a forested watershed in Kanagawa Prefecture, Central Japan was estimated by measuring dissolved inorganic N (DIN; NH₄ ⁺ + NO₃ ^– + NO₂ ^–) from Nov 2004 through Oct 2005. The estimated N budget (–1.43 kg N ha^–1 year^–1) showed that the N output rate (stream water N) was higher than the N input rate (bulk deposition N) in the watershed. The annual NO₂ ^– and NO₃ ^– input rates were 0.02 and 1.99 kg N ha^–1 year^–1, respectively. NH₄ ⁺ was the predominant source in this forested watershed, accounting for 71% (4.99 kg N ha^–1 year^–1) of DIN input rate. In addition, this study estimated rainfall pH, air temperature, and wind direction, which were considered as controlling factors related to the atmospheric deposition rate of NH₄ ⁺. This study showed that the rainfall NH₄ ⁺ was inversely proportional to the initial pH of the rainfall, which was calculated by adding the amount of H⁺ consumed by the dissociation process of NH_3(aq) to the measured rainfall pH. This result implies that acid rain can elevate the solubility of NH_3(g) and the dissociation capacity of NH₄ ⁺ throughout the process of precipitation. Also, this study provides strong evidence that the high NH₄ ⁺ deposition rate is mainly derived from NH_3(g) emitted from livestock wastes under the NH₃ transport condition of warm summer and favorable wind direction.