Acidification Effect Research Articles

Soil Acidification from Long‐Term Use of Anhydrous Ammonia and Urea

AbstractAcidity generated by N fertilizers depends on factors such as the composition of the fertilizer, climatic and soil conditions, and the crops grown. Our objective was to quantify the acidifying effects of urea and anhydrous NH3 when used as fertilizers for cereal production in Saskatchewan, Canada. The fertilizers were injected annually (at 10‐cm depth) into a medium‐textured, moderately acid (pH ≈5.5) Typic Haploboroll, at rates of 0, 45, 90, and 180 kg N ha−1 for 9 yr. Soil acidity increased as N application rate increased, with anhydrous NH3 causing greater acidification than urea. Although pH values as low as 4.3 were recorded in soil treated with anhydrous NH3, KCl‐exchangeable acidity remained low. The major effect of acidification was a depletion of exchangeable Ca and Mg. The solubility of Mn (but not Al) increased substantially as pH decreased, with solution concentrations of almost 30 mg Mn L−1 being recorded 6 d after injection of NH3. Acidity generated by anhydrous NH3 compared well with values predicted assuming that all of the applied NH3 was oxidized to NO3− (with the production of 1 mol H+ mol−1 of N) and that these protons were partly neutralized by OH− released when NO3− was taken up and assimilated by plants. Acidification due to export of bases in grain was insignificant because wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) remove only a slight excess of cations over anions. Urea failed to realize its full acidification potential because of an apparent loss of urea‐N from the soil by NH3 volatilization.

An investigation of the impact of afforestation on stream-water chemistry in the Loch Dee catchment, SW Scotland

The impact of conifer afforestation on stream-water chemistry was investigated in the acidified catchment of Loch Dee, SW Scotland. Long-term trends in stream-water chemistry were evaluated during a period of forest growth from age 6 to 17 years. A significant increase was observed for pH (0.2 units) and a significant decline for aluminium (0.05 mg litre −1), sulphate (1.2 mg litre −1) and nitrate (0.02 mg litre −1) concentrations. The long-term decrease in stream-water acidity was ascribed to the marked reductions in sulphur depositions during the 1970s and early 1980s. There was no evidence that this response had been attenuated by afforestation, the improvements in stream-water chemistry being of a similar magnitude to those recorded in nearby moorland lochs and exceeding that in an adjacent moorland-catchment stream. The lack of a clear forest acidification effect is consistent with deposition-model estimates which show the increased scavenging of occult and dry deposition by the growing forest to be small at this site (≤10%). Critical load calculations suggest that planned emission reductions will be sufficient to protect the catchment stream from further acidification by 2003. The additional deposition capture by the continued growth of the forest is predicted to delay this response by approximately 2 years.

Nutrient balance in Scots pine (Pinus sylvestris L.) forest. 2. Effects of plant growth and N-deposition on soil solution and leachate chemistry in a lysimeter experiment

Three years of N application to a Cambic arenosol (Typic Udorthent) in two lysimeter series, one with and one without young saplings of Pinus sylvestris L. have produced significant changes in soil solution and leachate chemistry. An application of 30 kg N/ha * yr -1 significantly increased NO 3 - leaching from the soil. This N load was also sufficient to significantly increase the mobility of the phyto-toxic elements Al 3+ and Mn 2+ , likewise to increase leaching of the important plant nutrients Ca 2+ , Mg 2+ and K + . At a N load of 90 kg N/ha*yr -1 significant increase in NH 4 + leaching was observed, but total leaching of NH 4 + was still very low compared to NO 3 - leaching. No significant treatment effects were found for SO 4 2- , Fe 2+ and Cl - in the leachate. Trees grown in the lysimeters buffered the acidifying effect of N application and increased the leachate pH by 0.2 pH units compared to lysimeters without trees.

Effects of alkaline buffers on cytoplasmic pH in lymphocytes

To study experimentally possible adverse effects of bicarbonate on cytoplasmic pH. Open, randomized control trial of white blood cells from human volunteers. Experimental laboratory in a large university hospital. Lymphocytes prepared from human blood. The fluorescent intracellular probe 2',7'-bis-(carboxyethyl)-5,6-carboxyfluorescein acetoxymethyl ester (BCECF-AM) was used to study the influence on cytoplasmic pH after the addition of different alkaline buffers to lymphocytes with normal as well as decreased initial intracellular pH. In normal lymphocytes, sodium bicarbonate caused a marked, dose-dependent acidification of the cytoplasm followed by a slow, often unpredictable increase. Ringer's acetate solution decreased the intracellular pH dose-dependently this acidification effect continued throughout the measurements. In contrast, trometamol (tris) and Carbicarb both caused a pronounced dose-dependent and lasting alkalinization of the cytoplasm. Tris buffer mixture (Tribonate) produced a slight initial dose-dependent acidification, followed by a slow increase in cytoplasmic pH to values above those recorded during control measurements. Lymphocytes that were preincubated in acetate showed similar results after addition of tris buffer mixture or sodium bicarbonate. Lymphocytes with intracellular acidosis due to preincubation in an acid buffer demonstrated a more pronounced and dose-dependent decrease of cytoplasmic pH immediately after addition of the bicarbonate-containing buffers (sodium bicarbonate and tris buffer mixture). The decrease was only partly compensated for over the next 10 mins. Only the buffers that were not producing CO2 could fully compensate for the severe extra- and intracellular acidosis imposed on the lymphocytes by preincubation in an acid medium. Use of bicarbonate-containing buffers often results in an initial decrease of cytoplasmic pH.

Soil acidification from use of too much fertilizer

Abstract Excess soil acidification caused by fertilizers is a major factor in world‐wide soil deterioration. Fertilizers, particularly nitrogen, acidify soil mostly when too much is used (in excess of crop needs). Acidity is otherwise caused by differential cation‐anion uptake by plants which varies with species. A crop can acidify the soil whether or not commercial fertilizers are used, like if the nitrogen came from the soil organic matter or from symbiotic nitrogen fixation. When the exact amount of nitrogen that is needed is applied to land, little acidification results unless nontillage is practiced to give soil surface acidification. In that case the acidification can equal the theoretical. For ammonium‐N, the theoretical is twice the value given in fertilizer handbooks and if there are no plant roots in the soil surface, the full acidification effect is expressed. There are plant species and cultivar differences on soil acidification caused by differential cation‐anion uptake. Legumes acidify soil considerably.

The effects of below-cloud aerosol on the acidification process of rain

Using a model of the acidification process of rain, we calculate and analyze the effects and contributions of a below-cloud aerosol in its different concentrations and acidities on the pH and ion components of rain (SO 4 2− , H+, NO 3 − , NH 4 + , etc.) under the conditions of different concentrations of pollution gases. The results show that the aerosol has an acidification or alkalization effect on the rain which changes the pHs of rain and aerosol. As acidifying pollution gas concentrations (SO2, HNO3) are low, the acid aerosol has important effects on the pH and H+ of rain, but as the gas concentrations are high, the acid aerosol has very little effect. The alkalizing aerosol makes the pH of rain increase by between 0.3 and 0.5 and neutralizes about 60% of H+ in the rain. As alkalizing pollution gas NH3 exists, the acid aerosol has important effects on the pH and H+ of rain. But the alkalizing aerosol has very little effect, especially as the NH3 concentration is high. The percentage contribution of the aerosol to SO 4 2− in rain is generally 7–15%, the contribution of the aerosol to NO 3 − is nearly the same as that of HNO3=1 ppb, and the contribution of the aerosol to NH 4 + is nearly the same as that of NH3, from 5 to 7 ppb, and is an important source of NH 4 + in rain. Finally, according to the actual conditions of typical regions in the south and north of China (Chongqing and Beijing), we analyze the effects of aerosol and pollution gases on the ion components of rain.

Acidification of weaner pig diets: A review

AbstractThe potential of diet acidification to overcome the digestive insufficiency and postweaning lag in early weaned pigs is examined in the review. A survey of published data on various types of acidifiers reveal considerable variation in response to acidification of weaner diets. Several reasons may be proposed to explain the inconsistencies in response, these include differences in diet type, age of pigs, type and level of acidifier, and existing performance levels. Reducing the gastric pH does not appear to be the primary effect of acidifiers. Acidification, however, consistently suppressed pathogenic coliforms in the gastrointestinal tract. Future developments in the use of acidifiers would be intrinsically linked to the understanding of their mode(s) of action in the animal.

Long-term N fertilization of a solonetzic soil: Effects on chemical and biological properties

A field experiment was conducted at Vegreville (east-central Alberta) to determine the residual effect of various amounts of fertilizer N on chemical and biological properties of a Solonetzic soil. The experiment was established in 1961 and soil samples were taken in 1986. Five fertilizer treatments were applied from 1961 to 1978: 0, 76, 152 and 305 kg N ha −1 as ammonium nitrate (AN) and 74 kg N ha −1 plus 139kg P ha −1 as monoammonium phosphate (MAP). Nitrogen fertilization with AN depressed the pH of the Ap horizon from 5.7 in the unfertilized N treatment to 4.2 with 305 kg N ha −1 and this acidification effect was more pronounced with MAP than at the equivalent rate of N with AN. Fertilizer N caused a significant decrease in extractable Mg in the Ap horizon. There was a trend towards decreased sodium adsorption ratio (SAR), soluble Na, and extractable Na and Ca, with applied N. Microbial biomass C and N, and the amount of mineralizable C and N decreased with N fertilization, with the lowest values at the highest rates of fertilizer application. However, total soil organic carbon and soil organic N increased with N application.

SYNTHESIS AND CH-ACIDITY OF N,N-DISUBSTITUTED AMINOTRIPHENYL-PHOSPHONIUM SALTS

Abstract A number of (substituted-methylamino)triphenylphosphonium salts (APS) with the general formula [Ph3P+N(R)CH2R'] X− has been synthesized. CH-Acidity of some of the APS obtained has been measured (pK 14.7-24.8) by an indicator method in DMSO/counterion-K+, standard-9-phenyl fluorene (pK 18.5)/. Acidification effect of the Ph3P+N(Ph) group ([sgrave]= CH2 = 0.70) and of the Ph3P+N(Bu) group ([sgrave]− CH2 = 0.68) has been estimated. The data obtained testify to the presence of an effective positive charge on the nitrogen atom in the APS under study and also to a somewhat increased multiplicity of the nitrogen-phosphorus bond as compared to a single one.

Synthesis and CH-acidity of N,N-disubstituted aminotriphenylphosphonium salts

Several substituted methylaminotriphenylphosphonium salts (APS) of general formula $$[Ph_3 \mathop P\limits^ + N(R)CH_2 R']X^ - $$ have been synthesized. The CH-acidities of some of the prepared APS have been measured by the indicator method in DMSO, with K+ counterion and 9-phenylfluorene (pK 18.5) as standard, showing a pK range of 14.7–24.8. The acidification effect of $$Ph_3 \mathop P\limits^ + N(Ph)(\sigma _{CH_2 } ^ - = 0.70)$$ and $$Ph_3 \mathop P\limits^ + N(Bu)(\sigma _{CH_2 } ^ - = 0.68)$$ groups has been evaluated. The results obtained suggest that there is an effective charge on the nitrogen atom in the APS studied and an increased multiplicity of the N-P bond.

Screening of Anionic Salts for Palatability, Effects on Acid-Base Status, and Urinary Calcium Excretion in Dairy Cows

Six anionic salts [MgCl2·6H2O, MgSO4·7H2O, CaCl2·2H2O, CaSO4·2H2O, NH4Cl, and (NH4)2SO4] were evaluated for their effects on dietary DM intake, systemic acid-base balance, and urinary excretion of Ca. Each of the six salts was fed to 12 nonlactating, nonpregnant Holstein cows for l-wk periods in two replicates of a 6×6 Latin square design. All salts were fed at the rate of two equivalents cow–1 d–1. Anionic salt treatments did not decrease DM intake compared with the control diet fed without salts. Blood pH was not affected by any of the salt treatments; however, mild, compensated metabolic acidosis was evidenced by decreased blood bicarbonate concentrations and decreased blood base excess when any of the salts was fed. Urinary pH and urinary base excess also were lowered by all of the salts. Fractional excretion of urinary Ca was increased by all salt treatments. All six anionic salts tested were of similar value in their acidifying effects and in their ability to increase urinary excretion of Ca.

The effect of source of nitrogen on the dry matter yield, nitrogen and nitrate‐N content ofLolium multiflorum

Three sources of N fertilizer (urea, limestone ammonium nitrate (LAN) and ammonium sulphate) showed no consistent significant trends in terms of the dry matter yield and nitrogen or nitrate‐N content of midmar ryegrass. Ammonium sulphate was found to acidify the soil markedly, relative to urea, with LAN showing the least acidifying effect.

Use of Lime-Stabilized Dairy-Plant Waste for Forage Production

A lime stabilized sludge (LSS) from a dairy wastewater treatment plant was evaluated in field studies on a silt loam soil as a source of lime and P for a tall fescue (Festuca arundinacea Shreb.) meadow. An initial treatment of almost 9000 gal/acre significantly increased hay yields and raised the surface soil (0–3 in.) above the pH and Bray and Kurtz no. 1 P sufficiency levels for tall fescue. Supplemental N and K were required to achieve maximum yields of the fescue treated with the lime stabilized biomass. There was sufficient reserve lime in the LSS to offset the acidifying effects of 4 yr of NH4NO3 topdressing.

Growth and biocatalytic activities of aerobic thermophilic populations in sewage sludge

Enzymatic activities of aerobic thermophilic microorganisms are described and investigated for the development and control of sewage sludge treatment processes in batch and fed-batch cultures. Proteolytic activity is the main enzymatic activity in an aerobic thermophilic sewage sludge treatment process. It has an optimum at 80°C and can be found also during growth on synthetic media. The activity is correlated with the increase in ammonium in the particle-free fraction and the values of the respiratory quotients during cultivation either in sewage sludge or in a syntheticc medium. No other extracellular activities (lipase, amylase, pectinase and cellulase) were detected in the investigated sludge samples. Carbohydrates, lipids and other polymers were either not present in significant amounts or passed with only minor modifications through the treatment. Cultivations in sewage sludge were either oxygen or carbon limited. One strain able to excrete lysozyme was isolated. It might have a synergistic effect on the heat inactivation of pathogenic microorganisms (cryptic growth) although lytic activity remained very low. Two-thirds of the entire metabolic activity is due to degradation of insoluble matter. The utilization of particulate matter also has a positive influence on the efficiency of the process by reduction in dry matter and increase in water-removal properties. Even at extremely low aeration rates, the acidification effect was small. Only small amounts of isobutyrate, isovaleriate and 2-methylbutyrate were formed at extremely low aeration rates and caused an increase in the total volatile fatty acid content after 12 and 36 h cultivation time.

Gas‐phase acidity of nitrobenzene from flowing afterglow bracketing studies

AbstractRoom temperature ion/molecule reactions in 0.30 Torr of helium, carried out in a flowing afterglow, show that the gas‐phase acidity of nitrobenzene is intermediate between those of ethanol and isopropanol, in contrast to published high‐pressure mass spectrometer data. The revised gas‐phase acidity of nitrobenzene, ΔHºacid(C6H5NO2) = 377 ± 3 kcal mol−1, is shown to be consistent with known acidifying effects when a hydrogen atom is replaced by a nitro group in a Brönsted acid. Additional reactions involving nitrobenzene or its conjugate base are noted.

Laboratory study of soil acidification and leaching of nutrients from a soil amended with various surface-incorporated acidifying agents

Granular S, finely-ground S, iron sulphate and aluminium sulphate were added at two rates to the surface (0–6 cm) of a soil and acidification and leaching of nutrients were measured over 12 months in a laboratory study. Iron and aluminium sulphate both rapidly lowered soil pH in the top 0–6 cm of the soil. There was little difference in soil pH after 3 and 12 months reaction of these two amendments. In contrast, for granular S and finely-ground S there were clear decreases in soil pH between 3 and 12 months reaction with the soil. Finely-ground S was oxidized in the soil faster than granular S and therefore had a more acidifying effect. The top 0–6 cm of the soil was acidified by all the agents used but the deeper soil was less affected. The only treatments which lowered the pH of the 12–18 cm layer below pH 6 were the high rates of iron and aluminium sulphate. Soil acidification resulted in a decrease in exchangeable Ca, Mg and K, an increase in exchangeable Al and a decrease in effective CEC in the acidified soil layers.

Temporal chemical variability in acid sensitive high elevation lakes

Chemical indicators suggest that slight, but discernable acidification occurs during smowmelt in some highly sensitive Cascade Mountain Lakes (mean alkalinity 20 ueq L−1). Although some SO4 in the lakes (mean 13 μeq L−1 ) comes from local geologic sources, several considerations suggest that some also comes from atmospheric deposition and anthropogenic sources. If sampling is stratified, the relatively low lake-to-lake and year-to-year variability in chemical constituents demonstrates that these highly sensitive lakes represent excellent indicators of acidification. The contention that precipitation pH >4.6 is needed for protection of sensitive lakes is supported. However, the slight but temporary acidification effect currently detectable during snowmelt, suggests that for adequate protection of these highly sensitive lakes, precipitation pH should be >4.7 to 4.8.

Relative acidifying effects of tricarbonylchromium(0) and p-nitro groups upon di- and triphenylmethanes

Relative acidifying effects of tricarbonylchromium(0) and p-nitro groups upon di- and triphenylmethanes

Effects of acidic desposition on forest soil and vegetation

The paper concerns the potential effects of acidic deposition on the nutrient status of soil and forest and on the possible toxic effect of increased Al solubility. The nutrient status of trees may be influenced by pollutants interacting with the foliage and also by changing availability of nutrients in the soil. N compounds are often absorbed by the canopy whereas base cations are lost to the soil by foliar leaching. Cation leaching increases with increased acidity of precipitation. Throughfall acidity varies with tree species, season and distance from the emission areas. The impact of increased foliar leaching of base cations is not well known. In soil, acid deposition may have three effects: (i) a fertilizer effect caused by the deposition of N, and possibly, under specific conditions, also of S; (ii) an acidification effect caused by increased leaching of base cations; and (iii) an Al toxicity effect in cases where soil acidity is increased. Results of fertilizer experiments indicate that the atmospheric deposition of N is likely to increase forest growth especially in the northern parts of North America and Europe. At more southerly latitudes, nutrients in addition to N are often deficient. Therefore the N deposition is less likely to stimulate forest growth. Sulphur deposition is not likely to increase forest growth in most areas of the temperate zone. On the contrary, S deposition will mostly increase leaching of base cations such as Mg 2+ and Ca 2+ , and possibly K. Experiments with artificial acidification together with observations of increased Mg-deficiency in central Europe, indicate that Mg-deficiency might become a problem on sensitive soils exposed to acid deposition. The possibility of Al toxicity caused by increased soil acidity is discussed on the basis of experiments with seedlings of Norway spruce. It is concluded that Al toxicity appears to be unlikely unless the Al concentrations in the soil solution increase to about 20 mg l -1 .

Acidification of a Solonetzic soil by nitrogenous fertilizers.

Annual applications of (NH4)2SO4, NH4NO3 and urea on a Solonetzic soil at 112 kg N/ha for 10 consecutive years reduced pH levels from 5.6 for the check to 4.4, 4.9 and 5.3, respectively for (NH4)2SO4, NH4NO3 and urea. (NH4)2SO4 generated twice as much exchange acidity as NH4NO3 and four times as much as urea. Net extractable cations leached from the Ap horizon closely approximated the amount of exchange acidity generated by (NH4)2SO4 and NH4NO3 fertilizers. The levels of soil extractable Al and Mn were greatly enhanced by (NH4)2SO4 as were plant contents. Similar acidifying effects to that produced by the (NH4)2SO4 occurred when NH4NO3 was applied at 300 kg N/ha annually for 12 consecutive years in another field experiment on the same soil. Liming samples of the field (NH4)2SO4 acidified soils in the greenhouse, significantly increased yields and lowered the Al and Mn contents of the plants to normal levels.