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1.
Rain event samples have been collected in Haifa, Israel, for nine hydrological years 1981 to 1990. Precipitation amount, pH, SO4 =, NO3 ?, Cl?, NH4 +, Na+, K+, Ca++, Mg++ and alkalinity of rainwater samples were recorded. The sampling and analysis program was based on WMO recommendations for background networks. The sampling was performed manually, and the analysis was based on wet chemistry for ions and atomic absorptions for metals. Data of 187 rain samples showed that the average pH was 5.3±1.1∶ 26% of the rain events were below pH of 5.6 and 23% above pH of 7.0. Some simple chemical mass-balance considerations indicate that natural sources, sea salt and soil carbonates are the main contributors to rain chemistry. However, the presence of low pH events observed over the years suggests that the impact of anthropogenic emissions may overwhelm the buffering capacity of the alkaline aerosol.  相似文献   

2.
The condition around coniferous trees in the soil is becoming gradually acidic when acid rain falls continuously. Nutrient uptake by the roots of coniferous trees could be affected in such environmental change of root zone. The experiments of water culture of coniferous seedlings in modified systems were carried out using (2-and, 3-year-old) of Japanese cedar(Cryptomeria japonica) and, Japanese cypress(Chamaecyparis obtusa) that are the typical Japanese forest trees. Nine major nutrients such as Na+, NH4 +, K+, Ca2+, Mg2+, Cl?, NO3 ?, PO4 3?, and SO4 2?, were given in the water culture solution and growth of trees was observed for two years. The aspects of nutrient uptake by these seedlings and the effects of acidity in culture solution were observed. The following results were obtained. 1) Japanese cedar of 50% and Japanese cypress of 30 % in tested seedlings could live for two years. 2) All Japanese cedar and cypress that started in the strong acidic condition ( pH=3.0) were dead within three months. 3) The minimum pH value in the acidic condition is estimated as 3.2 for these coniferous seedlings, and it means that they can live at least for two years in this condition. 4) The seasonal pattern of the uptake of nitrogen nutrient by Japanese cedar was determined.  相似文献   

3.
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 NO3 ? leaching from the soil. This N load was also sufficient to significantly increase the mobility of the phyto-toxic elements Al3+ and Mn2+, likewise to increase leaching of the important plant nutrients Ca2+, Mg2+ and K+. At a N load of 90 kg N/ha*yr?1 significant increase in NH4 + leaching was observed, but total leaching of NH4 + was still very low compared to NO3 ? leaching. No significant treatment effects were found for SO4 2?, Fe2+ 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.  相似文献   

4.
Chemical and Statistical Analysis of Precipitation in Singapore   总被引：1，自引：0，他引：1  
The results of chemical analyses of precipitation samples collected in Singapore between August 1997 and July 1998 are presented. Major inorganic and organic ions were determined in 169 rain samples collected using an automated wet-only sampler. The daily sample pH values ranged from 3.49 to 6.54 with a volume-weighted mean of 4.50, and about 88% of the samples had pH values less than 5.0 Nss-SO4 2? accounted for about 53 % of the sum of anions in rain, whereas chloride, nitrate, formate, and acetate accounted for the remainder. Rain chemistry data were analyzed using principal component analysis to find possible sources of the measured chemical species. Three components that accounted for 83.5% of the total variance were extracted: sea-spray (Na+, Cl? and and Mg2+) and soil particles (Ca2+ and K+), acid factor (nss-SO4 2?, NO3 ?, NH4 +, and H+), and biomass burning (HCOO? and CH3COOO?).  相似文献   

5.
Rain water at two forested sites in Guangzhou (south China) show high concentrations of SO4 2?, NO3 ? and Ca2+ and display a remarkable seasonal variation, with acid rain being more important during the spring and summer than during the autumn and winter. The amount of acid rain represents about 95% of total precipitation. The sources of pollutants from which acid rain developed includes both locally derived and long-middle distance transferred atmosphere pollutants. The seasonal variation in precipitation chemistry was largely related to the increasing neutralizing capacity of base cations in rainwater in winter. Soil acidification is highlighted by high H+ and Al3+ concentrations in soil solutions. The variation in elemental concentration in soil solution was related to nitrification (H+, NH4 + and NO3 ?) and cation exchange reaction (H+, Al3+) in soil. The negative effect of soil acidification is partly dampened by substantial deposition of base cations (Ca2+, Mg2+ and K+) in this area.  相似文献   

6.
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.  相似文献   

7.
A model deciduous forest soil (Schaffenaker loamy sand) was treated for 8 mo in the greenhouse in 25 cm reconstructed columns with simulated throughfall at pH 6.0 or 4.0, and SO4 2? levels of 12.8 or 24.8 mg L?1. Red oak seedlings grown in the microcosms showed no growth or foliar element response to the treatments. Sulfate loading had a greater impact on soil and leachate chemistry than pH. Higher available soil P in the A, horizon was associated with the pH 6.0 and high SO4 2?2 treatment combination. High SO4 2? loading also reduced exchangeable K+ in the A1?. Other soil horizons were unaffected by either treatment. Leachate chemistry was not significantly altered by througfall pH, but significantly greater export of Na+, Ca2+, Mg2+, Al3+, and NO3 ?, and lower SO4 2? loss, occurred with low SO4 ? input. Comparatively half as much NO3 ? loss was associated with high SO4 2? deposition. The high rate of NO3 ? leaching appeared responsible for greater equivalent mass loss of cations from the low SO4 2? treatment. Leachate removal of SO4 2? approximated input after 8 mo. The capacity of this soil to adsorb SO4 2? appeared relatively limited in the absence of normal element cycling. The sulfate component of simulated deciduous forest throughfall was shown to have a potentially greater impact than pH on ion leaching from forest soil. Additional consideration of the role of SO2? 4 deposition, in the context of throughfall rather than incident precipitation, is warranted in studies of acidic deposition effects on internal forest soil processes.  相似文献   

8.
Summer solarization of six wet field soils of four different textures raised soil temperatures by 10–12°C at 15cm depth. Soil solarization increased concentrations of NO?3N and NH+4N up to six times those in nontreated soils. Concentrations of P, Ca2+, Mg2+ and electrical conductivity (EC) increased in some of the solarized soils. Solarization did not consistently affect available K+, Fe3+, Mn2+, Zn2+, Cu2+, Cl? concentrations, soil pH or total organic matter. Concentrations of mineral nutrients in wet soil covered by transparent polyethylene film, but insulated against solar heating, were the same as those in nontreated soil. Increases in NO?3N plus NH+4N were no longer detected in fallowed soils 9 months after solarization. No significant correlation between mineral-nutrient concentration in plant tissue and plant growth was found. Fresh and dry weights of radish, pepper and Chinese cabbage plants usually were greater when grown in solarized soils than in nontreated soils. Fertilization of solarized soils sometimes resulted in greater plant growth responses than observed in solarized but nonfertilized soils.  相似文献   

9.

Purpose

Long-term manure applications can prevent or reverse soil acidification by chemical nitrogen (N) fertilizer. However, the resistance to re-acidification from further chemical fertilization is unknown. The aim of this study was to examine the effect of urea application on nitrification and acidification processes in an acid red soil (Ferralic Cambisol) after long-term different field fertilization treatments.

Materials and methods

Soils were collected from six treatments of a 19-year field trial: (1) non-fertilization control, (2) chemical phosphorus and potassium (PK), (3) chemical N only (N), (4) chemical N, P, and K (NPK), (5) pig manure only (M), and (6) NPK plus M (NPKM; 70 % N from M). In a 35-day laboratory incubation experiment, the soils were incubated and examined for changes in pH, NH4 +, and NO3 ?, and their correlations from urea application at 80 mg N kg?1(?80) compared to 0 rate (?0).

Results and discussion

From urea addition, manure-treated soils exhibited the highest acidification and nitrification rates due to high soil pH (5.75–6.38) and the lowest in the chemical N treated soils due to low soil pH (3.83–3.90) with no N-treated soils (pH 4.98–5.12) fell between. By day 35, soil pH decreased to 5.21 and 5.81 (0.54 and 0.57 unit decrease) in the NPKM-80 and M-80 treatments, respectively, and to 4.69 and 4.53 (0.43 and 0.45 unit decrease) in the control-80 and PK-80 treatments, respectively, with no changes in the N-80 and NPK-80 treatments. The soil pH decrease was highly correlated with nitrification potential, and the estimated net proton released. The maximum nitrification rates (K max) of NPKM and M soils (14.7 and 21.6 mg N kg?1 day?1, respectively) were significantly higher than other treatments (2.86–3.48 mg N kg?1 day?1). The priming effect on mineralization of organic N was high in manure treated soils.

Conclusions

Field data have shown clearly that manure amendment can prevent or reverse the acidification of the red soil. When a chemical fertilizer such as urea is applied to the soil again, however, soil acidification will occur at possibly high rates. Thus, the strategy in soil N management is continuous incorporation of manure to prevent acidification to maintain soil productivity. Further studies under field conditions are needed to provide more accurate assessments on acidification rate from chemical N fertilizer applications.  相似文献   

10.
Effects of simulated acid rain, comprised of HNO3 and H2SO4 in the mole ratio of 3:1, at pH 5.6, 4.5, 4.0 and 3.0, were tested on the grass, soft chess (Bromus mollis L.) and on clover (Trifolium subterraneum L. var. Woogenellup) in a sandy soil of granodiorite parent material. Soft chess was grown in unfertilized soil, whereas clover was grown in both unfertilized soil and soil fertilized with NH4NO3 and CaSO4·2H2O at the rates of 224 kg ha?1 N and 78 kg ha?1 S. Two acid-spray irrigation periods of 31 and 26 weeks duration, each delivering 400 mm and separated by a dry period of 23 weeks, simulated typical rainfall of northern California rangeland. Plants were harvested after each of the two spray periods. There were very few deleterious effects of acid rain on plant growth or soil and microbial processes. No significant (p<0.05) effects were shown by soil microbial biomass, CO2 production, nodules per unit weight of clover root, acetylene reduction, denitrification and nitrification potentials, or for soft chess plant weights, and N and P uptake. Mineralizable-N was unaffected also, except in one case. However, pH of soil to 10 mm depths was significantly lower in the pH 3.0 treatment after the first spray period, with a corresponding decrease in exchangeable soil Ca; these effects became significant at greater soil depth only after the second spray period. There were significant effects of acid treatments shown by clover, some of which may be advantageous. Treatments of intermediate acidity generally provided added N and S, which acted as fertilizers, and compensated for possible decreases in plant productivity attributable to acidity per se. There was also evidence of decreased P uptake in unfertilized soil at pH 3. In conclusion, effects of simulated acid rain were minimal, and in some cases were advantageous because of the added N and S having a fertilizer effect on plant nutrition and growth.  相似文献   

11.
A field study was carried out to analyze the short-term impacts of replacing mineral by organic fertilizers on the microbial and biochemical parameters relevant for soil fertility and crop yield. Three types of fertilization regimes were compared: (1) conventional fertilizer regime with inorganic fertilizer, and combined integrated fertilizer regimes in which 25 % of the nutrients were supplied by either (2) rabbit manure or (3) vermicompost. The effects on microbial community structure and function (phospholipid fatty acid [PLFA] profiles, bacterial growth, fungal growth, basal respiration, β-glucosidase, protease and phosphomonoesterase activities), soil biochemical properties (total C, dissolved organic carbon [DOC], N-NH4 +, N-NO3 ?, PO4, total K) and crop yield were investigated in the samples collected from the experimental soil at harvest, 3 months after addition of fertilizer. The integrated fertilizer regimes stimulated microbial growth, altered the structure of soil microbial community and increased enzyme activity relative to inorganic fertilization. Bacterial growth was particularly influenced by the type of fertilizer regime supplied, while fungal growth only responded to the amount of fertilizer provided. The use of manure produced a fast increase in the abundance of PLFA biomarkers for Gram-negative bacteria as compared to inorganic fertilizer. Nutrient supply and crop yield with organic fertilizers were maintained at similar levels to those obtained with inorganic fertilizer. The effects of the organic amendments were observed even when they involved a small portion of the total amount of nutrients supplied; thereby confirming that some of the beneficial effects of integrated fertilizer strategies may occur in the short term.  相似文献   

12.
Abstract

Rice variety IR 36, grown under flooding, was studied in 1998 to determine the effects of fly ash, organic, and inorganic fertilizers on changes in pH and organic carbon, release of nutrients (NH4 +-N, Bray's P, and NH4OAc K), and dehydrogenase activity in an acid lateritic soil at 15-day intervals. Application of fly ash at 10?t?ha?1 alone did not improve the availability of NH4 +-N, or P, as well as the rice grain yield. Availability of NH4 +-N (35.3–36.9?mg?kg?1), and P (12.3–14.6?mg?kg?1) at 15 days after transplanting, and rice grain yields (48.0–51.7?g per pot) were similar under the various fertilization sources such as inorganic fertilizer alone, inorganic fertilizer?+?fly ash or inorganic fertilizer?+?green manure?+?fly ash. Mean dehydrogenase activity was the highest (8.47?µg triphenyl formazon g?1 24?h?1) under the mixed fertilization treatments with green manure. At the end of the cropping season (75 days after transplanting), pH, organic carbon, and dehydrogenase activity were higher under the mixed fertilization treatments involving green manure by 3, 15 and 154%, respectively, compared with the inorganic fertilizer alone.  相似文献   

13.
A long-term hydrological and water chemistry research was conducted in three experimental microbasins differing in land cover: (1) a purely agricultural fertilized microbasin, (2) a forested microbasin dominated by Carpinus betulus (European hornbeam), and (3) a forested microbasin dominated by Picea abies (L.) (Norway spruce). The dissolved inorganic nitrogen (DIN: NH 4 + , NO 2 ? , NO 3 ? ) budget was examined for a period of 3 years (1991–1993). Mean annual loads of DIN along with sulfate SO 4 2? and base cations Ca2+, Mg2+, Na+, K+, and HCO 3 ? were calculated from ion concentrations measured in stream water, open-area rainfall, throughfall (under tree canopy), and streamwater at the outlets from the microbasins. Comparison of the net imported/exported loads showed that the amount of NO 3 ? leached from the agricultural microbasin is ～3.7 times higher (43.57 kg ha?1?a?1) than that from the spruce dominated microbasin (11.86 kg ha?1?a?1), which is a markedly higher export of NO 3 ? compared to the hornbeam dominated site. Our analyses showed that land cover (tree species) and land use practices (fertilization in agriculture) may actively affect the retention and export of nutrients from the microbasins, and have a pronounce impact on the quality of streamwater. Sulfate export exceeded atmospheric rainfall inputs (measured as wet deposition) in all three microbasins, suggesting an additional dry depositions of SO 4 2? and geologic weathering.  相似文献   

14.
Zhou  Meng  Liu  Xiaobing  Meng  Qingfeng  Zeng  Xiannan  Zhang  Jizhou  Li  Dawei  Wang  Jie  Du  Weiling  Ma  Xianfa 《Journal of Soils and Sediments》2019,19(10):3521-3533
Purpose

Serious soil salinization, including excessive exchangeable sodium and high pH, significantly decreases land productivity. Reducing salinity and preventing alkalization in saline-sodic soils by comprehensive improvement practices are urgently required. The combinations of aluminum sulfate with different types of fertilizer at different rates were applied on rice paddy with saline-sodic soils of the Songnen Plain in Northeast China to improve soil quality and its future utilization.

Materials and methods

Experiments were carried out in a completely randomized block design. Twelve treatments with aluminum sulfate at the rates of 0, 250, 500, and 750 kg hm?2 with inorganic, bio-organic, and organic-inorganic compound fertilizers were performed. Soil pH, electronic conductivity (EC), cation exchangeable capacity (CEC), exchangeable sodium percentage (ESP), total alkalinity, sodium adsorption ratio (SAR), soil organic carbon (SOC), available nutrients, soluble ions, rice growth, and yield in the saline-sodic soils were measured across all treatments. The relationships among the measured soil attributes were determined using one-way analysis of variance, correlation analysis, and systematic cluster analysis.

Results and discussion

The pH, EC, ESP, total alkalinity, SAR, Na+, CO32?, and HCO3? in saline-sodic soil were significantly decreased, while CEC, SOC, available nitrogen (AN), available phosphorus (AP), available potassium (AK), K+, and SO42? were significantly increased due to the combined application of aluminum sulfate with fertilizer compared with the fertilizer alone. The most effective treatment in reducing salinity and preventing alkalization was aluminum sulfate at a rate of 500 kg hm?2 with organic-inorganic compound fertilizer. This treatment significantly decreased the soil pH, EC, ESP, total alkalinity, SAR, Na+, and HCO3? by 5.3%, 28.9%, 41.1%, 39.3%, 22.4%, 23.5%, and 35.9%, but increased CEC, SOC, AN, AP, AK, K+, SO42?, rice height, seed setting rate, 1000-grain weight, and yield by 77.5%, 115.5%, 106.3%, 47.1%, 43.3%, 200%, 40%, 6.2%, 43.9%, 20.3%, and 42.2%, respectively, compared with CK treatment in the leaching layer.

Conclusions

The combined application by aluminum sulfate at a rate of 500 kg hm?2 with organic-inorganic compound fertilizer is an effective amendment of saline-sodic soils in Songnen Plain, Northeast China. These results are likely related to the leaching of Na+ from the soil leaching layer to the salt accumulation layer and desalination in the surface soil, and the increase of SOC improved the colloidal properties and increased fertilizer retention in soil. In addition, the environmental impact of aluminum sulfate applied to soil needs to be further studied.

  相似文献   

15.
Precipitation chemistry and atmospheric element-deposition in an agroecosystem at the North-Sea Coast of Schleswig-Holstein The objective of this study was to examine the chemistry of bulk precipitation and atmospheric element inputs in an arable soil near the North Sea coast of Schleswig-Holstein, North Germany. Bulk precipitation was collected at weekly intervals from November 1989 to October 1991. Precipitation amount, pH, electrical conductivity, and concentrations of Na+, K+, NH4+, Mg2+, Ca2+, Cl?, NO3?, and SO42? were recorded. The average volume-weighted pH was 5.5 and the average EC was 92 μS cm?1. Sodium and Cl? were with 64% and 76% the dominant ions (equivalent concentration) in bulk precipitation indicating the influence of the North Sea. The contribution of marine alkalinity to neutralization reactions of bulk precipitation was negligible (1%). The neutralizing substances NH3 (63%) and Carbonate (36%) were more important. Deposition rates were in 1990 and 1991 97.0 and 51.7 kg Na+ ha?1, 6.2 and 4.0 kg K+ ha?1, 15.0 and 8.4 kg Mg2+ ha?1, 13.2 and 10.4 kg Ca2+ ha?1, 12.3 and 9.5 kg NH4+-N ha?1, 8.0 and 5.9 kg NO3?-N ha?1, 168 and 83.1 kg Cl? ha?1 and 19.1 and 12.7 kg SO42?-S ha?1. In 1990 both more westerly winds and stronger wind-forces occurred than in 1991 and resulted in higher inputs of marine origin. Calculated on Cl? basis 93% of Na+, 55% of K+, 74% of Mg2+, 24% of Ca2+, and 36% of SO42? were of marine origin. Atmospheric input of marine origin supplied 39–72% of Mg and 21–37% of S requirement for crop production. The North Sea is an important source providing significant amounts of these elements to agricultural crops.  相似文献   

16.
ABSTRACT

Soil degradation due to salinization and sodication is the paramount threat in Indo-Gangetic plains. The studies on reclamation and management of such soils can provide a pragmatic solution for improving fertility and productivity of these soils. Lack of organic matter and poor availability of nutrients are the major factors for low productivity of sodic soils. Rice-wheat is a major cropping system in Indo-Gangetic alluvial plain region even in reclaimed sodic soils and farmers used inorganic fertilizers only to get higher yields. In this study, we used different organic sources of amendments in conjunction with different nitrogen (N) doses supplied through inorganic fertilizers to investigate the combined effect of organic and inorganic amendments on soil fertility and the productivity of rice- wheat system in sodic soils. Salt tolerant varieties of rice and wheat were grown in sodic soil (pH: 9.30, EC: 1.12 dSm?1 and exchangeable sodium percentage, ESP: 52) during 2014–15 to 2016–17 in a field experiment with 13 treatment combinations of organic and inorganic amendments (T1- (control) 100% of recommended dose of N (RDN), T2-municipal solid waste compost (MSWC) @10 t ha?1 + 50%RDN, T3- MSWC @10 t ha?1 + 75% RDN,T4- MSWC @10 t ha?1 + 100%RDN, T5-Vermicompost (VC) @10 t ha?1 + 50% RDN, T6- VC @10 t ha?1 + 75% RDN, T7-VC@10 t ha?1 + 100% RDN, T8- Farm yard manure (FYM) @ 10 t ha?1 + 50% RDN,T9- FYM@10 t ha?1 + 75%RDN, T10- FYM@10 t ha?1 + 100% RDN, T11-Pressmud (PM) @10 t ha?1 + 50% RDN, T12-PM@10 t ha?1 + 75%RDN, and T13- PM @ 10 t ha?1 + 100% RDN). Use of organic amendments supplemented with reduced dose of N through inorganic fertilizer has significantly improved soil bio-physical and chemical properties. Application of VC@10 t ha?1 + 100% RDN (T7) decreased soil bulk density, pH, EC, ESP and Na content to 2.0, 4.2, 26.5, 42.8, and 56.6% respectively and increased soil organic carbon by 34.6% over control (T1). Soil fertility in terms of available N, P, K, Ca, and Mg increased by 20.5, 33.0, 36.4, and 44%, respectively, over control (T1). Soil microbial biomass carbon, nitrogen, and phosphorus also improved significantly due to combined use of organic amendments and inorganic fertilizers over the only use of inorganic fertilizers. Decreasing in soil sodicity and increasing soil fertility showed significant increase (P < 0.05) in crop growth, growth indices, and grain yields of rice and wheat. The study revealed that combined use of VC or MSW compost @10 t ha?1 in conjunction with 75% RDN through inorganic fertilizers in sodic soils proved sustainable technology for restoration of degraded sodic soils and improving crop productivity.  相似文献   

17.
The influence of tree species and soil properties on throughfall fluxes were studied for 5 tree species, growing on initially identical soil. In three mixed deciduous forests with different soil properties, throughfall fluxes of 11 elements were measured during 2 yr for 100 to 150 yr old individuals of Fagus sylvatica L., Quercus robur L., Carpinus betulus L., Tilia cordata Mill. and Acer platanoides L.. Throughfall : precipitation flux ratios were: PO4 3? (11 to 37), K+ (7 to 22), Mn2+ (5 to 14), Mg2+ (3 to 9), Ca2+ (3 to 5), Cl? (1.9 to 2.6), Na+ (1.1 to 2.2), NH4 + (1.5 to 2), SO4 2? (1.5 to 2.1), NO3 ? (0.7 to 1.3) and H+ (0.1 to 0.5). The annual input of S to the soil by throughfall was for Fagus 22 to 29, Quercus 25 to 37, Carpinus 20 to 25, Tilia 24 and Acer 29 kg ha?1. The annual input of N to the soil by throughfall was for Fagus 20 to 29, Quercus 14 to 22, Carpinus 15 to 22, Tilia 22 and Acer 20 kg ha?1. Throughfall fluxes of Na+ and Cl? differed between species, depending on different canopy filtering capacity of sea aerosol, and were greatest for Fagus and Quercus. Throughfall of Ca2+, Mg2+ and K+ were characterized by increased flux from poor to rich sites, with the greatest soil effect on Carpinus, and by a high leaching part, which increased in the same manner. Manganese throughfall showed especially soil effects, characterized of decreased flux from poor to rich sites, but also species effects, of which Carpinus had the greatest flux. pH in throughfall showed a pronounced seasonal variation with pH 6 to 6.5 for Fagus in the foliated season and pH 4.0 to 4.3 in the defoliated season. Carpinus and especially Quercus had lower pH at the poor site, but the differences decreased at the richer sites. The calculated annual acid input to the trees was 4 to 12 times greater than the H+ flux measured as pH in throughfall. An inorganic anion deficit in throughfall, probably due to the presence of organic anions, was proportional to K+, Ca2+ and Mg2+.  相似文献   

18.
Acid rain impacts on the small forested watershed in northern Tama Hills in the western Tokyo metropolitan area Japan were investigated by surveying the trends of major inorganic species in rain and spring water during the years from 1991 to 1997. The ecosystem had been stressed by the annual H+-deposition of around 0.43 kmol/ha. The spring water outflow corresponded to ca. 27% of the precipitation. Budgets for the precipitation input and spring water output gave good balance for Cl?,?0.01 ±0.09 kmol/ha, net gains for H+, NO3 ? and SO4 2?, and to the contrary, relatively large net losses for Na+, Mg2+, Ca2+, Si(as H4SiO4) and HCO3 ?, thus suggesting the dissolution of chemical weathered products of silicate minerals. Further, in spring water, some concentration relationships were found: CNa+ = 376.5?2.05CCl? (R2=0.748), CNa+=12.69+0.5556CHCO3 ? (R2=0.872) and CH4SiO4=130.0 + 1.108CHCO3 ? (R2=0.816). Evidently, the spring water chemistry reflected probable geochemical changes in the soil layer of the watershed. Mass balance in the ecosystem and estimation of the spring water output of chemical weathered products were investigated  相似文献   

19.
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.  相似文献   

20.
Fogwater, fog drip and rainwater chemistry were examined at a tropical seasonal rain forest in Xishuangbanna, southwest China between November 2001 and October 2002. During the period of observation, 204 days with the occurrence of radiation fog were observed and the total duration of fog was 1949 h, of which 1618 h occurred in the dry season (November to April), accounting for 37.0% of the time during the season. The mean pH of fogwater, fog drip and rainwater were 6.78, 7.30, and 6.13, respectively. The ion with the highest concentration for fog- and rainwater was HCO3 ?, which amounted to 85.2 and 37.3 μeq l?1, followed by Ca2+, Mg2+ and NH4 +. Concentrations of NO3 ?, HCO3 ?, NH4 +, Ca2+, and K+ in fogwater samples collected in the dry season were significantly greater when compared to those collected in the rainy season. It was found that the ionic concentrations in fog drip were higher than those in fogwater, except for NH4 + and H+, which was attributed to the washout of the soil- and ash-oriented ions deposited on the leaves and the alkaline ionic emissions by the leaves, since biomass burns are very common in the region and nearby road was widening.  相似文献   

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