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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Soil use and management 14 (1998), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Emissions of ammonia (NH3) and nitrous oxide (N2O), and nitrate (NO-3) leaching were measured in two field experiments following application of pig slurry at rates corresponding to 83–96 kg NH4-N ha-1 before sowing. In spring and in autumn 1994, slurry was applied by four methods: trenching (T), shallow injection (S), band spreading immediately followed by harrowing (B/H) and band spreading (B). NH3 emission measurements were made during the first week after application in both experiments. In the spring experiment N2O emissions and NO-3 leaching were measured during 6 and 52 weeks after spreading respectively, and during 11 and 33 weeks after spreading in the autumn experiment. In spring, the increased N2O emissions (i.e. control subtracted) ranged from 0.27% (T) to 0.45% (B/H), and in the autumn study from 0.92% (T) to 1.14% (B/H), of applied NH4-N, although showing no statistically significant differences. In order to validate the chamber measurements, a ‘megachamber’(21 m2) was used together with an infrared spectrometer. The emissions agreed well for (B/H), while (B) resulted in lower emissions compared with the smaller chambers. Emissions of NH3 were about one order of magnitude higher. In spring, (B) gave the highest emission, reaching 19.5% of applied NH4-N, whereas (S), and (B/H) gave the lowest emissions, reaching 1.2 and 3.5% of applied NH4-N, respectively. NH3 emissions in autumn were 15–20% lower compared with spring. In spring the increased nitrate leaching ranged from 10.1 (T) to 24.9 kg ha-1 (B/H) and from 29.5 (B) to 37.8 kg ha-1 (T) in the autumn experiment, showing no statistically significant differences. Estimations of indirect N2O emissions due to ammonia deposition and nitrate leaching, suggested that the N2O contribution from NH3 deposition was relatively small, while the indirect N2O emissions from NO-3 leaching were of the same order of magnitude or higher than the direct N2O emissions.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Soil use and management 15 (1999), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. The recommended method of reducing the emission of NH3 while spreading manure is to plough or harrow the manure into the soil. This in turn increases the possibility of N2O emission. At two sites in southern Sweden emissions of NH3 and N2O were measured after spreading pig slurry by broadcasting and band spreading. The band spreading technique can be used in growing crops i.e. when nitrogen is most needed, and it is thought that the NH3 emission is smaller with this technique compared to broadcasting. The average NH3 loss was 50% of applied NH4+ during warm/dry conditions and 10% during cold/wet conditions. The N2O emission was always less than 1% of applied NH4+. When the NH3 emission decreased, the direct N2O emission increased. However, when taking into account the indirect N2O emission due to deposition of NH3 outside the field, the spreading techniques all produced similar total N2O emissions. The ammonia emission was not much lower for the band spreading technique compared to broadcasting, when compared on seven occasions.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Soil use and management 13 (1997), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. The large boreal peatland ecosystems sequester carbon and nitrogen from the atmosphere due to a low oxygen pressure in waterlogged peat. Consequently they are sinks for CO2 and strong emitters of CH4. Drainage and cultivation of peatlands allows oxygen to enter the soil, which initiates decomposition of the stored organic material, and in turn CO2 and N2O emissions increase while CH4 emissions decrease. Compared to undrained peat, draining of organic soils for agricultural purposes increases the emissions of greenhouse gases (CO2, CH4, and N2O) by roughly 1t CO2 equivalents/ha per year. Although farmed organic soils in most European countries represent a minor part of the total agricultural area, these soils contribute significantly to national greenhouse gas budgets. Consequently, farmed organic soils are potential targets for policy makers in search of socially acceptable and economically cost-efficient measures to mitigate climate gas emissions from agriculture. Despite a scarcity of knowledge about greenhouse gas emissions from these soils, this paper addresses the emissions and possible control of the three greenhouse gases by different managements of organic soils. More precise information is needed regarding the present trace gas fluxes from these soils, as well as predictions of future emissions under alternative management regimes, before any definite policies can be devised.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1365-2486
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography
    Notes: This paper reports the range and statistical distribution of oxidation rates of atmospheric CH4 in soils found in Northern Europe in an international study, and compares them with published data for various other ecosystems. It reassesses the size, and the uncertainty in, the global terrestrial CH4 sink, and examines the effect of land-use change and other factors on the oxidation rate.Only soils with a very high water table were sources of CH4; all others were sinks. Oxidation rates varied from 1 to nearly 200 μg CH4 m−2 h−1; annual rates for sites measured for ≥1 y were 0.1–9.1 kg CH4 ha−1 y−1, with a log-normal distribution (log-mean ≈ 1.6 kg CH4 ha−1 y−1). Conversion of natural soils to agriculture reduced oxidation rates by two-thirds –- closely similar to results reported for other regions. N inputs also decreased oxidation rates. Full recovery of rates after these disturbances takes 〉 100 y. Soil bulk density, water content and gas diffusivity had major impacts on oxidation rates. Trends were similar to those derived from other published work. Increasing acidity reduced oxidation, partially but not wholly explained by poor diffusion through litter layers which did not themselves contribute to the oxidation. The effect of temperature was small, attributed to substrate limitation and low atmospheric concentration.Analysis of all available data for CH4 oxidation rates in situ showed similar log-normal distributions to those obtained for our results, with generally little difference between different natural ecosystems, or between short-and longer-term studies. The overall global terrestrial sink was estimated at 29 Tg CH4 y−1, close to the current IPCC assessment, but with a much wider uncertainty range (7 to 〉 100 Tg CH4 y−1). Little or no information is available for many major ecosystems; these should receive high priority in future research.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Forest Ecology and Management 66 (1994), S. 69-86 
    ISSN: 0378-1127
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Chromatography A 361 (1986), S. 107-116 
    ISSN: 0021-9673
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 25 (1997), S. 296-301 
    ISSN: 1432-0789
    Keywords: Key words Methane ; Forest soil ; pH ; Liming ; Nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Methane uptake to soil was examined in individual chambers at three small forest catchments with different treatments, Control, Limed and Nitrex sites, where N-deposition was experimentally increased. The catchments consisted of both well-drained forest and wet sphagnum areas, and showed uptake of CH4 from the ambient air. The lowest CH4 uptakes were observed in the wet areas, where the different treatments did not influence the uptake rate. In the well-drained areas the CH4 uptakes were 1.6, 1.4 and 0.6 kg ha–1 year–1 for the Limed, Control and Nitrex sites, respectively. The uptake of methane at the well-drained Nitrex site was statistically smaller than at the other well-drained catchments. Both acidification and increase in nitrogen in the soil, caused by the air-borne deposition, are the probable cause for the reduction in the methane uptake potential. Uptake of methane was correlated to soil water content or temperature for individual chambers at the well-drained sites. The uptake rate of methane in soil cores was largest in the 0- to 10-cm upper soil layer. The concentration of CH4 in the soil was lower than the atmospheric concentration up to 30 cm depth, where methane production occurred. Besides acting as a sink for atmospheric methane, the oxidizing process in soil prevents the release of produced methane from deeper soil layers reaching the atmosphere.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 6 (1988), S. 106-111 
    ISSN: 1432-0789
    Keywords: Nitrification ; Denitrification ; Soil water content ; N2O production ; Acetylene ; Ammonium fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effect of soil water content [60%–100% water-holding capacity (WHC)] on N2O production during autotrophic nitrification and denitrification in a loam soil was studied in a laboratory experiment by selectively inhibiting nitrification with a low C2H2 concentration (2.1 Pa). Nitrifiers usually produced more N2O than denitrifiers. During an initial experimental period of 0–6 days the nitrifiers produced more N2O than the denitrifiers by a factor ranging from 1.4 to 16.5, depending on the water content and length of incubation. The highest N2O production rate by nitrifiers was observed at 90% WHC, when the soil had become partly anaerobic, as indicated by the high denitrification rate. At 100% WHC there were large gaseous losses from denitrification, while nitrification losses were smaller except for the first period of measurement, when there was still some O2 remaining in the soil. The use of 10 kPa C2H2 to inhibit reduction of N2O to N2 stimulated the denitrification process during prolonged incubation over several days; thus the method is unsuitable for long-term studies.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0789
    Keywords: Denitrification ; Nitrification ; Selective inhibitors ; Nitrapyrin ; Acetylene ; Nitrous oxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Nitrapyrin and C2H2 were evaluated as nitrification inhibitors in soil to determine the relative contributions of denitrification and nitrification to total N2O production. In laboratory experiments nitrapyrin, or its solvent xylene, stimulated denitrification directly or indirectly and was therefore considered unsuitable. Low partial pressures of C2H2 (2.5–5.0 Pa) inhibited nitrification and had only a small effect on denitrification, which made it possible to estimate the contribution of denitrification. The contribution of nitrification was estimated by subtracting the denitrification value from total N2O production (samples without C2H2). The critical C2H2 concentrations needed to achieve inhibition of nitrification, without affecting the N2O reductase in denitrifiers, must be individually determined for each set of experimental conditions.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-0789
    Keywords: Key words N2O emission ; Spruce forest ; Catchments ; Lime ; N-addition ; Water content ; Temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Fluxes of N2O were studied in a Norway spruce forest in the southwest of Sweden. Three differently treated catchments were compared: Limed (6 t dolomite ha–1), Nitrex (additional N-deposition corresponding to 35 kg ha–1 year–1, in small doses) and Control (used as control site). The N-retention was still high (95%) after 2years of N-addition at the Nitrex site when the flux measurements were performed. Each catchment contained both well-drained and poorly drained soils (covered with Sphagnum sp.). The emissions of N2O were in general low with both a high spatial and temporal variation for all three sites. The measured emissions were 25, 71 and 96 (gN2O-N ha–1 year–1) for the well-drained Limed, Control and Nitrex sites, respectively. The average emissions of N2O from the wet areas were significantly higher than the well-drained areas within the catchments. For the wet areas the measured emissions were larger: 90, 118 and 254 (g N2O-N ha–1 year–1) for the Limed, Control and Nitrex sites, respectively. Comparison between treatments showed the wet Nitrex site to have a significantly higher emission than all other sites. The increased N-deposition at the Nitrex site increased the N2O emissions by 0.2% of the added N for the well-drained soils and about 1% for the wet areas, compared with the control site. Since the wet areas represented only a small part of the forest, their larger emissions did not contribute significantly to the overall emission of the forest. Neither temperature nor water content of the soil was well correlated with the N2O emissions. Soil gas samples showed that most of the N2O was produced below a 0.3-m depth in the soil.
    Type of Medium: Electronic Resource
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