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1.
C. Alejandra Villamar Teresa Cañuta Marisol Belmonte Gladys Vidal 《Water, air, and soil pollution》2012,223(1):363-369
Since swine wastewater is used by farmers for soil fertilization, evaluation of toxic compounds or micro-contaminants of separate
streams is required. This paper uses the toxicity identification evaluation (TIE) procedure for the physicochemical and ecotoxicological
characterization of swine wastewater. To distinguish the most important toxic compounds, a physicochemical characterization
and phase I-TIE procedure were performed. The acute toxic effect of swine wastewater and treated fractions (phase II-TIE)
were evaluated using Daphnia magna determining 48-h LC50. Results show a high level of conductivity (23.5 μS cm−1), which is explained as due to the concentration of ions, such as ammonium (NH4+–N 1.6 g L−1), sulfate (SO42− 397.3 mg L−1), and chlorine (Cl− 1,230.0 mg L−1). The acute toxicity of the swine wastewater was evaluated on D. magna (48-h LC50 = 3.4%). Results of the different water treatments indicate that anionic exchange treatments could reduce 22.5% of swine
wastewater’s acute toxicity by reducing chlorine (to around 51%) and conductivity (8.5%). On the other hand, cationic exchange
treatment increased acute toxicity on D. magna (% RT = −624.4%), by reducing NH4+–N (around 100%) and total nitrogen (95.5%). This finding suggests that part of the toxicity comes from anionic compounds,
such as chlorine. 相似文献
2.
Balaji Anandha Rao Cameron P. Wake Todd Anderson William Andrew Jackson 《Water, air, and soil pollution》2012,223(1):181-188
Temporal depositional rates are important in order to understand the production and occurrence of perchlorate (ClO4−) as limited information exists regarding the impact of anthropogenic production or atmospheric pollution on ClO4− deposition. Perchlorate concentrations in discrete ice core samples from the Eclipse Icefield (Yukon Territory, Canada) and
Upper Fremont Glacier (Wyoming, USA) were analyzed using ion chromatography tandem mass spectrometry to evaluate temporal
changes in the deposition of ClO4
− in North America. The ice core samples cover a time period from 1726 to 1993 and 1970 to 2002 for the Upper Fremont Glacier
(UFG) and Eclipse ice cores, respectively. The average ClO4
− concentration in the Eclipse ice core for the time period from 1970 to 1973 was 0.6 ± 0.3 ng L−1, with higher values of 2.3 ± 1.7 and 2.2 ± 2.0 ng L−1 for the periods 1982–1986 and 1999–2002, respectively. All pre-1980 ice core samples from the UFG had ClO4
− concentrations <0.2 ng L−1, and the post-1980 samples ranged from <0.2 ng L−1 to a maximum of 2.6 ng L−1 for the year 1992. A significant positive correlation (R = 0.75, N = 15, p < 0.001) of ClO4− with SO42− was found for the annual UFG ice core layers and of ClO4
− with SO42− and NO3− in sub-annual Eclipse ice samples (R > 0.3, N = 121, p < 0.002). The estimated yearly ClO4− depositional flux for the Eclipse ice core ranged from 0.6 (1970) to 4.7 μg m−2 year−1 (1982) and the UFG from <0.1 (pre-1980) to 1.4 μg m−2 year−1 (1992). There was no consistent seasonal variation in the ClO4− depositional flux for the Eclipse ice core, in contrast to a previous study on the Arctic region. The presence of ClO4− in these ice cores might correspond to an intermittent source such as volcanic eruptions and/or any anthropogenic forcing
that may directly or indirectly aid in atmospheric ClO4− formation. 相似文献
3.
The photochemical degradation of two widely used organophosphorothioate insecticides, fenitrothion and diazinon, was investigated
in aqueous solutions containing three separate dissolved constituents commonly found in natural waters (NO3−, CO32− and dissolved organic matter (DOC)). The effect of these constituents on pesticide photodegradation was compared to degradation
in “constituent-free” pure water. Solutions were irradiated in an Atlas solar simulator fitted with a UV-filtered Xenon arc
lamp with light irradiances (500 W m−2) measured using a spectral radiometer to allow derivation of quantum yields of degradation. Fenitrothion absorbs light within
the solar UV range (λ, 295–400 nm) and underwent direct photolysis in pure water whereas diazinon (λ
max ∼250 nm) showed no observable loss over the experimental period. However, photodegradation conforming to pseudo-first-order
kinetics was observed for both chemicals in the presence of the dissolved constituents (at concentrations typically observed
in natural waters), with the rates of photodecay observed in the order of NO3− > CO32− ≅ DOC, with the highest rates observed in the 3 mM NO3− solutions (k
Fen = 0.155 ± 0.041 h−1; k
Dia = 0.084 ± 0.0007 h−1). For diazinon this rate was comparable to fenitrothion photolysis in pure water (k
fen 0.072 ± 0.0078 h−1), highlighting the importance of NO3− on a non-photolabile pesticide, with indirect photodegradation probably attributable to the light-induced release of aqueous
hydroxyl radicals (·OH) from NO3−. Suwannee river fulvic acid (serving as DOC) did not statistically affect the rate of photodecay for fenitrothion relative
to its photolysis in MilliQ water, although measured rates in DOC solutions were slightly lower. However, measurable rates
of photodecay were apparent for diazinon in the DOC solutions, indicating that fulvic acid, possibly in the form of “excited”
triplet-state-DOC plays a role in diazinon transformation. Hydrolysis was not apparent for fenitrothion (in buffered solutions
of pH 5–9) but was notable for diazinon at the lower pHs of 5 and 3 (k
Dia-hyd 0.3414 h−1 at pH 3 and 0.228 h−1 at pH 5), resulting in the formation of the degradate, 2-isopropyl–6-methyl–4-pyrimidinol. This work highlights the importance
of dissolved constituents on abiotic photodegradation of pesticides and it is recommended that these constituents be incorporated
into laboratory-based fate-testing regimes. 相似文献
4.
Crop residues and fertilizer nitrogen influence residue decomposition and nitrous oxide emission from a Vertisol 总被引:2,自引:0,他引:2
Wisal Muhammad Sarah M. Vaughan Ram C. Dalal Neal W. Menzies 《Biology and Fertility of Soils》2011,47(1):15-23
Crop residues with high C/N ratio immobilize N released during decomposition in soil, thus reducing N losses through leaching,
denitrification, and nitrous oxide (N2O) emission. A laboratory incubation experiment was conducted for 84 days under controlled conditions (24°C and moisture content
55% of water-holding capacity) to study the influence of sugarcane, maize, sorghum, cotton and lucerne residues, and mineral
N addition, on N mineralization–immobilization and N2O emission. Residues were added at the rate of 3 t C ha−1 to soil with, and without, 150 kg urea N ha−1. The addition of sugarcane, maize, and sorghum residues without N fertilizer resulted in a significant immobilization of
soil N. Amended soil had significantly (P < 0.05) lower NO3−–N, which reached minimum values of 2.8 mg N kg−1 for sugarcane (at day 28), 10.3 mg N kg−1 for maize (day 7), and 5.9 mg N kg−1 for sorghum (day 7), compared to 22.7 mg N kg−1 for the unamended soil (day 7). During 84 days of incubation, the total mineral N in the residues + N treatments were decreased
by 45 mg N kg−1 in sugarcane, 34 mg kg−1 in maize, 29 mg kg−1 in sorghum, and 16 mg kg−1 in cotton amended soil compared to soil + N fertilizer, although soil NO3−–N increased by 7 mg kg−1 in lucerne amended soil. The addition of residues also significantly increased amended soil microbial biomass C and N. Maximum
emissions of N2O from crop residue amended soils occurred in the first 4–5 days of incubation. Overall, after 84 days of incubation, the
cumulative N2O emission was 25% lower with cotton + N fertilizer, compared to soil + N fertilizer. The cumulative N2O emission was significantly and positively correlated with NO3−–N (r = 0.92, P < 0.01) and total mineral N (r = 0.93, P < 0.01) after 84 days of incubation, and had a weak but significant positive correlation with cumulative CO2 in the first 3 and 5 days of incubation (r = 0.59, P < 0.05). 相似文献
5.
Balaji Rao Suhas Mohan Andreas Neuber William Andrew Jackson 《Water, air, and soil pollution》2012,223(1):275-287
Perchlorate (ClO4−), a thyroid hormone disruptor, is both naturally occurring and a man-made contaminant increasingly found in a variety of
terrestrial environments. The environmental presence of ClO4− is considered to be the result of atmospheric formation and deposition processes. The ultimate processes, particularly heterogeneous-based
reactions, leading to natural ClO4− formation are not well understood. Oxidation of chlorine species by an energetic source such as lightning is considered to
be one of the potential heterogeneous sources of natural ClO4−. Currently, there is very little information available on lightning-induced ClO4−. We designed a laboratory electrical discharge reactor capable of evaluating ClO4− formation by the oxidation of “dry” sodium chloride (NaCl) aerosols (relative humidity (RH) <70%) in electrical discharge
plasma at voltages and energies up to 24 kV and 21 kJ, respectively. Similar to other non-electrochemical ClO4− production processes, the amount of ClO4− produced (0.5–4.8 μg) was 3 orders of magnitude lower than the input Cl− (7.1–60.1 mg). The amount of ClO4− generated increased with peak voltage (V) and theoretical maximum discharge energy with ΔClO4−/ΔV = 0.28 × 10−3 μg V−1 (R
2 = 0.94) and ΔClO4−/ΔE = 0.44 × 10−3 μg J−1 (R
2 = 0.83). The total ClO4− generated decreased with an increase in relative humidity from 2.8 ± 0.1 μg (RH ∼46%) to 0.9 ± 0.1 μg (RH ∼62%) indicating
that the presence of moisture inhibits the formation of ClO4−. Additional modifications to the reactor support the hypothesis of ClO4− formation due to the action of plasma on Cl− aerosols as opposed to direct oxidation on the surface of the electrodes. Finally, the contribution of lightning-induced
ClO4− in North America is calculated to have a wide range from 0.006 × 105 to 5 × 105 kg/year and is within the range of the measured ClO4− depositional flux in precipitation samples obtained across the USA (0.09 × 105–1.2 × 105 kg/y). 相似文献
6.
In this study, the effects of 1 h aeration, nitrogen gas N2(g) sparging (15 and 30 min) and increasing ferric ions (Fe+3) as FeSO4 (10, 20 and 50 mg L−1) and Fe3O4 nanoparticles (1, 2 and 4 g L−1) concentrations on three less hydrophobic and three more hydrophobic polycyclic aromatic hydrocarbons (PAHs) and toxicity
removals from a petrochemical industry in Izmir (Turkey) were investigated in a sonicator with a power of 650 W and an ultrasound
frequency of 35 kHz; 1 h aeration increased the yields in benzo[b]fluoranthene, benzo[k]fluoranthene and benzo[a]pyrene PAHs (less hydrophobic) from 62% to 67% to around 95–97% after 150 min sonication at 60°C. However, 1 h aeration did
not contribute to the yields of more hydrophobic PAHs (indeno[1,2,3-cd]pyrene, dibenz[a,h]anthracene, benzo[g,h,i]perylene). The maximum yields were obtained at acidic and alkaline pH for more and less hydrophobic PAHs, respectively, after
60 and 120 min sonication at 30°C; 30 min N2(g) sparging, 50 mg L−1 Fe+3 increased the yields of less hydropobic PAHs after 150 min sonication at 60°C. Two milligrams per liter of Fe3O4 nanoparticles increased both less (87–88%) and more (96–98%) hydrophobic PAH yields. The Daphnia magna acute toxicity test showed that the toxicity decreased significantly with an hour aeration, 30 min N2(g) sparging, 50 mg L−1 Fe+3 and 2 g L−1 Fe3O4 nanoparticles at 60°C after 120 and 150 min sonications. Vibrio fischeri was found to be more resistant to the sonicated samples than D. magna. Significant correlations were found between the physicochemical properties of sonicated PAHs and acute toxicities both organisms. 相似文献
7.
Robert John Wilcock Karin Müller Gareth B. van Assema Margaret A. Bellingham Ron Ovenden 《Water, air, and soil pollution》2012,223(2):499-509
Water quantity and quality were monitored for 3 years in a 360-m-long wetland with riparian fences and plants in a pastoral
dairy farming catchment. Concentrations of total nitrogen (TN), total phosphorus (TP) and Escherichia coli were 210–75,200 g N m−3, 12–58,200 g P m−3 and 2–20,000 most probable number (MPN)/100 ml, respectively. Average retentions (±standard error) for the wetland over 3 years
were 5 ± 1%, 93 ± 13% and 65 ± 9% for TN, TP and E. coli, respectively. Retentions for nitrate–N, ammonium–N, filterable reactive P and particulate C were respectively −29 ± 5%,
32 ± 10%, −53 ± 24% and 96 ± 19%. Aerobic conditions within the wetland supported nitrification but not denitrification and
it is likely that there was a high conversion rate from dissolved inputs of N and P in groundwater, to particulate N and P
and refractory dissolved forms in the wetland. The wetland was notable for its capacity to promote the formation of particulate
forms and retain them or to provide conditions suitable for retention (e.g. binding of phosphate to cations). Nitrogen retention
was generally low because about 60% was in dissolved forms (DON and NOX–N) that were not readily trapped or removed. Specific yields for N, P and E. coli were c. 10–11 kg N ha−1 year−1, 0.2 kg P ha−1 year−1 and ≤109 MPN ha−1 year−1, respectively, and generally much less than ranges for typical dairy pasture catchments in New Zealand. Further mitigation
of catchment runoff losses might be achieved if the upland wetland was coupled with a downslope wetland in which anoxic conditions
would promote denitrification. 相似文献
8.
Simple and rapid chemical indices of soil nitrogen (N)-supplying capacity are necessary for fertilizer recommendations. In
this study, pot experiment involving rice, anaerobic incubation, and chemical analysis were conducted for paddy soils collected
from nine locations in the Taihu Lake region of China. The paddy soils showed large variability in N-supplying capacity as
indicated by the total N uptake (TNU) by rice plants in a pot experiment, which ranged from 639.7 to 1,046.2 mg N pot−1 at maturity stage, representing 5.8% of the total soil N on average. Anaerobic incubation for 3, 14, 28, and 112 days all
resulted in a significant (P < 0.01) correlation between cumulative mineral NH4+-N and TNU, but generally better correlations were obtained with increasing incubation time. Soil organic C, total soil N,
microbial C, and ultraviolet absorbance of NaHCO3 extract at 205 and 260 nm revealed no clear relationship with TNU or cumulative mineral NH4+-N. Soil C/N ratio, acid KMnO4-NH4+-N, alkaline KMnO4-NH4+-N, phosphate–borate buffer extractable NH4+-N (PB-NH4+-N), phosphate–borate buffer hydrolyzable NH4+-N (PBHYDR-NH4+-N) and hot KCl extractable NH4+-N (HKCl−NH4+-N) were all significantly (P < 0.05) related to TNU and cumulative mineral NH4+-N of long-term incubation (>28 days). However, the best chemical index of soil N-supplying capacity was the soil C/N ratio,
which showed the highest correlation with TNU at maturity stage (R = −0.929, P < 0.001) and cumulative mineral NH4+-N (R = −0.971, P < 0.001). Acid KMnO4-NH4+-N plus native soil NH4+-N produced similar, but slightly worse predictions of soil N-supplying capacity than the soil C/N ratio. 相似文献
9.
The abandonment of cultivated wetland soil increased the contents of light fraction organic matter (LFOM), heavy fraction
organic matter (HFOM) and soil organic matter (SOM). The LFOM and HFOM content increased to 13.3 g kg−1 and 62.4 g kg−1 after 5 years whereas they were 8.4 and 47.9 g kg−1 after 9 years of cropping, respectively. Fourteen years after abandonment, HFOM content increased to 104.3 g kg−1. LFOM was positively correlated with HFOM (p < 0.001). A Langmuir equation was used to calculate the highest HFOM value. The value for the natural wetland soil was closed
to this theoretical value (140.8 g kg−1). After 14 years of abandonment, the HFOM maximum (HFOMMax) value was lower than the equilibrium value suggesting that a further increase in HFOM can occur after abandonment. Assuming
a linear accumulation (3.87 Mg C ha−1yr−1), it would take approximately 24 years after the abandonment to reach the HFOMMax value. 相似文献
10.
Secondary salinity effects on soil microbial biomass 总被引:2,自引:0,他引:2
Dilfuza Egamberdieva Giancarlo Renella Stephan Wirth Rafiq Islam 《Biology and Fertility of Soils》2010,46(5):445-449
Secondary soil salinilization is a big problem in irrigated agriculture. We have studied the effects of irrigation-induced
salinity on microbial biomass of soil under traditional cotton (Gossypium hirsutum L.) monoculture in Sayhunobod district of the Syr-Darya province of northwest Uzbekistan. Composite samples were randomly
collected at 0–30 cm depth from weakly saline (2.3 ± 0.3 dS m−1), moderately saline (5.6 ± 0.6 dS m−1), and strongly saline (7.1 ± 0.6 dS m−1) replicated fields, 2-mm sieved, and analyzed for pH, electrical conductivity, total C, organic C (COrg), and extractable C, total N and P, and exchangeable ions (Ca2+, Mg2+, K+, Na+, Cl−, and CO32−), microbial biomass (Cmic). The Na+ and Cl− concentrations were 36-80% higher in strongly saline compared to weakly saline soil. The COrg concentration was decreased by 10% and CExt by 40% by increasing soil salinity, whereas decrease in Cmic ranged from 18-42% and the percentage of COrg present as Cmic from 8% to 26%. We conclude that irrigation-induced secondary salinity significantly affects soil chemical properties and
the size of soil microflora. 相似文献
11.
This study was conducted to investigate the effect of inorganic nitrogen (N) and root carbon (C) addition on decomposition
of organic matter (OM). Soil was incubated for 200 days with nine treatments (three levels of N (no addition (N0) = 0, low
N (NL) = 0.021, high N (NH) = 0.083 mg N g−1 soil) × three levels of C (no addition (C0) = 0, low C (CL) = 5, high C (CH) = 10 mg root g−1 soil)). The carbon dioxide (CO2) efflux rates, inorganic N concentration, pH, and potential activities of β-glucosidase and oxidative enzyme were measured
during incubation. At the beginning and the end of incubation, the native soil organic carbon (SOC) and root-derived SOC were
quantified by using a natural labeling technique based on the differences in δ
13C between C3 and C4 plants. Overall, the interaction between C and N was not significant. The decomposition of OM in the NH
treatment decreased. This could be attributed to the formation of recalcitrant OM by N because the potentially mineralizable
C pool was significantly lower in the NH treatment (3.1 mg C g−1) than in the N0 treatment (3.6 mg C g−1). In root C addition treatments, the CO2 efflux rate was generally in order of CH > CL > C0 over the incubation period. Despite no differences in the total SOC concentration
among C treatments, the native SOC in the CH treatment (18.29 mg C g−1) was significantly lower than that in the C0 treatment (19.16 mg C g−1). 相似文献
12.
Mohammad Mofizur Rahman Jahangir Dries Roobroeck Oswald Van Cleemput Pascal Boeckx 《Biology and Fertility of Soils》2011,47(7):753-766
Nitrous oxide (N2O) emissions, soil microbial community structure, bulk density, total pore volume, total C and N, aggregate mean weight diameter
and stability index were determined in arable soils under three different types of tillage: reduced tillage (RT), no tillage
(NT) and conventional tillage (CT). Thirty intact soil cores, each in a 25 × 25-m2 grid, were collected to a depth of 10 cm at the seedling stage of winter wheat in February 2008 from Maulde (50°3′ N, 3°43′ W),
Belgium. Two additional soil samples adjacent to each soil core were taken to measure the spatial variance in biotic and physicochemical
conditions. The microbial community structure was evaluated by means of phospholipid fatty acids analysis. Soil cores were
amended with 15 kg NO3−-N ha−1, 15 kg NH4+-N ha−1 and 30 kg ha−1 urea-N ha−1 and then brought to 65% water-filled pore space and incubated for 21 days at 15°C, with regular monitoring of N2O emissions. The N2O fluxes showed a log-normal distribution with mean coefficients of variance (CV) of 122%, 78% and 90% in RT, NT and CT, respectively,
indicating a high spatial variation. However, this variability of N2O emissions did not show plot scale spatial dependence. The N2O emissions from RT were higher (p < 0.01) than from CT and NT. Multivariate analysis of soil properties showed that PC1 of principal component analysis had
highest loadings for aggregate mean weight diameter, total C and fungi/bacteria ratio. Stepwise multiple regression based
on soil properties explained 72% (p < 0.01) of the variance of N2O emissions. Spatial distributions of soil properties controlling N2O emissions were different in three different tillages with CV ranked as RT > CT > NT. 相似文献
13.
Hadibarata Tony Yusoff Abdull Rahim Mohd Kristanti Risky Ayu 《Water, air, and soil pollution》2012,223(2):933-941
Utilization of microbes including white-rot fungi and bacterial strains for decolorization of synthetic dyes is one promising
strategy of an environmentally friendly and cost-competitive alternative to physico-chemical decomposition processes for treating
industrial effluents. In this study, the biodegradation ability of the white-rot fungi Polyporus sp. S133 that produce high laccase was investigated in order to decolorize anthraquinone-type dye. Parameter including pH,
temperature, and non-ionic surfactant were used to comparatively study the decolorizing effects on Remazol Brilliant Blue
R (RBBR). The purified laccase totally decolorized 200 mg L−1 initial concentration of RBBR dye when only 1.5 U L−1 of laccase was used in the reaction mixture. The optimal decolorization rates were achieved at pH 5 and at a temperature
of 50°C. N-hydroxybenzotriazole, a small molecular weight redox mediator, was found to accelerate the decolorization. Tween 20 inhibited
the decolorization while Tween 80 and Brij 35 showed no inhibition effect. Two compounds were identified as the intermediates
(m/z 304.3 and m/z 342.2). These results suggest that laccase from Polyporus sp. S133 is a powerful tool for the decolorization of anthraquinone dyes. A pathway for the metabolism of the RBBR by laccase
of Polyporus sp S133 was proposed. These proposed pathways could contribute to a better comprehension of the mechanisms used by oxidative
enzymes to transform organic compounds. 相似文献
14.
Joseph C. Fetter Rebecca N. Brown Josef H. Görres Chong Lee José A. Amador 《Water, air, and soil pollution》2012,223(4):1531-1541
Consumer demand for cleaned squid generates a substantial amount of waste that must be properly disposed of, creating an economic
burden on processors. A potential solution to this problem involves converting squid by-products into an organic fertilizer,
for which there is growing demand. Because fertilizer application to lawns can increase the risk of nutrient contamination
of groundwater, we quantified leaching of NO3–N and PO4–P from perennial ryegrass turf (Lolium perenne L.) amended with two types of fertilizer: squid-based (SQ) and synthetic (SY). Field plots were established on an Enfield
silt loam, and liquid (L) and granular (G) fertilizer formulations of squid and synthetic fertilizers were applied at 0, 48,
146, and 292 kg N ha−1 year−1. Levels of NO3–N and PO4–P in soil pore water from a depth of 60 cm were determined periodically during the growing season in 2008 and 2009. Pore
water NO3–N levels were not significantly different among fertilizer type or formulation within an application rate throughout the
course of the study. The concentration of NO3–N remained below the maximum contaminant level (MCL) of 10 mg L−1 until midSeptember 2009, when values above the MCL were observed for SQG at all application rates, and for SYL at the high
application rate. Annual mass losses of NO3–N were below the estimated inputs (10 kg N ha−1 year−1) from atmospheric deposition except for the SQG and SYL treatments applied at 292 kg N ha−1 year−1, which had losses of 13.2 and 14.9 kg N ha−1 year−1, respectively. Pore water PO4–P levels ranged from 0 to 1.5 mg P L−1 and were not significantly different among fertilizer type or formulation within an application rate. Our results indicate
that N and P losses from turf amended with squid-based fertilizer do not differ from those amended with synthetic fertilizers
or unfertilized turf. Although organic in nature, squid-based fertilizer does not appear to be more—or less—environmentally
benign than synthetic fertilizers. 相似文献
15.
Denitrification plays an important role in N-cycling. However, information on the rates of denitrification from horticultural
growing media is rare in literature. In this study, the effects of pH, N, C, and moisture contents on denitrification were
investigated using four moderately decomposed peat types (oligotrophic, mesotrophic, eutrophic, and transitional). Basal and potential denitrification rates (20°C, 18 h) from the unlimed peat samples varied widely from 2.0 to 21.8 and
from 118.9 to 306.6 μg (N2O + N2)–N L−1 dry peat h−1, respectively, with the highest rates from the eutrophic peat and the lowest from the transitional one. Both basal and potential
denitrification rates were substantially increased by 3.6–14- and 1.4–2.3-fold, respectively, when the initial pH (4.3–4.8)
was raised to 5.9–6.5 units. Emissions of (N2O + N2)–N from oligotrophic, mesotrophic, and transitional peats were markedly increased by the addition of 0.15 g NO3–N L−1 dry peat but further additions had no effect. Denitrification rates were increased by increasing glucose concentration suggesting
that the activity of denitrifiers in all peat types was limited by the low availability of easily decomposable C source. Increasing
moisture contents of all peats from 40 to 50% water-filled pore space (WFPS) did not significantly (p > 0.05) increase (N2O + N2)–N emissions. However, a positive effect was observed when the moisture contents were increased from 60% to 70% WFPS in the
eutrophic peat, from 70% to 80% in the transitional, from 80% to 90% in the oligotrophic and from 70% to 90% in the mesotrophic
peat. It can be concluded that liming, N-fertilization, availability of easily decomposable C, and moist condition above 60%
WFPS could encourage denitrification from peats although the rates are greatly influenced by the peat-forming environments
(eutrophic > mesotrophic > oligotrophic > transitional types). 相似文献
16.
Effects of moisture and temperature on greenhouse gas emissions and C and N leaching losses in soil treated with biogas slurry 总被引:1,自引:0,他引:1
The objective of this study was to examine the effects of soil moisture, irrigation pattern, and temperature on gaseous and
leaching losses of carbon (C) and nitrogen (N) from soils amended with biogas slurry (BS). Undisturbed soil cores were amended
with BS (33 kg N ha−1) and incubated at 13.5°C and 23.5°C under continuous irrigation (2 mm day−1) or cycles of strong irrigation and partial drying (every 6 weeks, 1 week with 12 mm day−1). During the 6 weeks after BS application, on average, 30% and 3.8% of the C and N applied with BS were emitted as carbon
dioxide (CO2) and nitrous oxide (N2O), respectively. Across all treatments, a temperature increase of 10°C increased N2O and CO2 emissions by a factor of 3.7 and 1.7, respectively. The irrigation pattern strongly affected the temporal production of CO2 and N2O but had no significant effect on the cumulative production. Nitrogen was predominantly lost in the form of nitrate (NO3−). On average, 16% of the N applied was lost as NO3−. Nitrate leaching was significantly increased at the higher temperature (P < 0.01), while the irrigation pattern had no effect (P = 0.63). Our results show that the C and N turnovers were strongly affected by BS application and soil temperature whereas
irrigation pattern had only minor effects. A considerable proportion of the C and N in BS were readily available for soil
microorganisms. 相似文献
17.
We compared, from 2004 through 2006, rates of soil–atmosphere CH4 exchange at permanently established sampling sites in a temperate forest exposed to ambient (control plots; ∼380 μL L−1) or elevated (ambient + 200 μL L−1) CO2 since August 1996. A total of 880 observations showed net atmospheric CH4 consumption (flux from the atmosphere to the soil) from all static chambers most of the time at rates varying from 0.02 mg m−2 day−1 to 4.5 mg m−2 day−1. However, we infrequently found net CH4 production (flux from the soil to the atmosphere) at lower rates, 0.01 mg m−2 day−1 to 0.08 mg m−2 day−1. For the entire study, the mean (±SEM) rate of net CH4 consumption in control plots was higher than the mean for CO2-enriched plots, 0.55 (0.03) versus 0.51 (0.03) mg m−2 day−1. Annual rates of 184, 196, and 197 mg m−2 for net CH4 consumption at control plots during the three calendar years of this study were 19, 10, and 8% higher than comparable values
for CO2 enriched plots. Differences between treatments were significant in 2004 and 2005 and nearly significant in 2006. Volumetric
soil water content was consistently higher at CO2-enriched sites and a mixed-effects model identified a significant soil moisture x CO2 interaction on net atmospheric CH4 consumption. Increased soil moisture at CO2-enriched sites likely increases diffusional resistance of surface soils and the frequency of anaerobic microsites supporting
methanogenesis, resulting in reduced rates of net atmospheric CH4 consumption. Our study extends our observations of reduced net atmospheric CH4 consumption at CO2-enriched plots to nearly five continuous years, suggesting that this is likely a sustained negative feedback to increasing
atmospheric CO2 at this site. 相似文献
18.
Shaharah Mohd Idris Paul L. Jones Scott A Salzman Graeme Allinson 《Water, air, and soil pollution》2012,223(2):549-557
Two emergent macrophytes, Arundo donax and Phragmites australis, were established in experimental subsurface flow, gravel-based constructed wetlands (CWs) and challenged by untreated stormwater
collected from the hard-pan and other surfaces of a dairy processing factory in south-west Victoria, Australia. The hydraulic
loading rate was tested at two levels, sequentially, 3.75 and 7.5 cm day−1. Some of the monitored variables were removed more efficiently by the planted beds in comparison to unplanted CWs (biochemical
oxygen demand (BOD), total nitrogen (TN) and total phosphorus (TP); p < 0.007) but there was no significant difference between the A. donax and P. australis CWs in removal of BOD, suspended solids (SS) and TN (p > 0.007) at 3.75 cm day−1 or SS and TN at 7.5 cm day−1. At 3.75 cm day−1, BOD, SS, TN and TP removal in the A. donax and P. australis CWs was 71%, 61%, 78% and 75% and 65%, 60%, 73% and 41%, respectively. Nutrient removal at 7.5 cm day−1 in the A. donax and P. australis beds was 87%, 91%, 84% and 71% and 96%, 94%, 87% and 55%, respectively. As expected, the A. donax CWs produced considerably more biomass (10 ± 1.2 kg wet weight) than the P. australis CWs (2.7 ± 1.2 kg wet weight). This equates to approximately 107 and 36 tonnes ha−1 year−1 biomass (dry weight) for A. donax and P. australis, respectively (assuming 250 days of growing season and single-cut harvest). The performance similarity of the A. donax- and P. australis-planted CWs indicates that either may be used in HSSF wetlands treating dairy factory stormwater, although the planting of
A. donax provides additional opportunities for secondary income streams through utilisation of the biomass produced. 相似文献
19.
The response of faba bean to the application of four rates of gypsum (0, 2.5, 5.0, 10.0 t ha−1) to a non-saline, alkaline sodic soil was measured in terms of grain yield, dry matter (DM) production, N accumulation and
the proportional dependence of the legume on symbiotic N2 fixation (P
atm). A yield-independent, time-integrated 15N-dilution model was used to estimate symbiotic dependence. A significant decrease in the exchangeable sodium percentage and
significant increases in exchangeable Ca++ and the Ca++:Mg++ ratio in the 0–10-cm soil layer were measured 30 months after application of 10 t ha−1 gypsum. Despite low and erratic rainfall during crop growth, faba bean DM and N uptake responded positively to gypsum application.
The symbiotic dependence of the legume at physiological maturity was little affected by sodicity (P
atm = 0.74 at zero gypsum and 0.81–0.82 at 2.5–10 t ha−1 gypsum). The increase in fixed N due to gypsum application was mainly due to increases in legume DM and total N uptake. At
10 t ha−1 of gypsum, faba bean fixed more than 200 kg N ha−1 in above-ground biomass. 相似文献
20.
Karoline D’Haene Annemie Van den Bossche Jeroen Vandenbruwane Stefaan De Neve Donald Gabriels Georges Hofman 《Biology and Fertility of Soils》2008,45(2):213-217
The effect of reduced tillage (RT) on nitrous oxide (N2O) emissions of soils from fields with root crops under a temperate climate was studied. Three silt loam fields under RT agriculture
were compared with their respective conventional tillage (CT) field with comparable crop rotation and manure application.
Undisturbed soil samples taken in September 2005 and February 2006 were incubated under laboratory conditions for 10 days.
The N2O emission of soils taken in September 2005 varied from 50 to 1,095 μg N kg−1 dry soil. The N2O emissions of soils from the RT fields taken in September 2005 were statistically (P < 0.05) higher or comparable than the N2O emissions from their respective CT soil. The N2O emission of soils taken in February 2006 varied from 0 to 233 μg N kg−1 dry soil. The N2O emissions of soils from the RT fields taken in February 2006 tended to be higher than the N2O emissions from their respective CT soil. A positive and significant Pearson correlation of the N2O–N emissions with nitrate nitrogen (NO3
−–N) content in the soil was found (P < 0.01). Leaving the straw on the field, a typical feature of RT, decreased NO3
−–N content of the soil and reduced N2O emissions from RT soils. 相似文献