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1.
Xianglan Li Wenping Yuan Hua Xu Zucong Cai Kazuyuki Yagi 《Nutrient Cycling in Agroecosystems》2011,91(3):293-305
Midseason aeration (MSA) of rice paddy fields functions to mitigate CH4 emission by a large margin, while simultaneously promoting N2O emission. Alternation of timing and duration of MSA would affect CH4 and N2O emissions from intermittently irrigated rice paddies. A pot trial and a field experiment were conducted to study the effect
of timing and duration of MSA on CH4 and N2O emissions from irrigated lowland rice paddy soils in China. Four different water regimes, i.e., early aeration, normal aeration
(the same as the local practice in timing and duration of aeration), delayed aeration, and prolonged aeration, were adopted
separately and compared with respect to global warming potential (GWP) of CH4 and N2O emissions and rice yields as well. Total emission of CH4 from the rice fields ranged from 28.6 to 64.1 kg CH4 ha−1, while that of N2O did from 1.71 to 6.30 kg N2O–N ha−1 during the study periods. Compared with the local practice, early aeration reduced CH4 emission by 13.3–16.2% and increased N2O emission by 19.1–68.8%, while delayed aeration reduced N2O emission by 6.8–26.0% and increased CH4 emission by 22.1–47.3%. The lowest GWP of CH4 and N2O emissions occurred in prolonged aeration treatment, however, rice grain yield was reduced by 15.3% in this condition when
compared with normal practice. It was found in the experiments that midseason aeration starting around D 30 after rice transplanting,
just like the local practice, would optimize rice yields while simultaneously limiting GWPs of CH4 and N2O emissions from irrigated lowland rice fields in China. 相似文献
2.
N2O emissions from a fertilized humid grassland near Cork, Ireland were continuously measured during 2003 using an eddy covariance
system. For most of the year emissions were close to zero and 60% of the emissions occurred in eight major events of 2–20 days’
duration. Two hundred and seven kg ha−1 of synthetic N and 130 kg ha−1 organic N were applied over the year and the total measured annual N2O emission was 11.6 kg N ha−1. The flux data were used to test the prediction of N2O emissions by the DNDC (DeNitrification – DeComposition) model. The model predicted total emissions of 15.4 kg N ha−1, 32 % more than the observed emissions. On this basis the model was further used to simulate (a) background (non-anthropogenic)
N2O emissions and (b) the effect on N2O emissions of future climate perturbations based on the Hadley Center model output of the IS92a scenario for Ireland. DNDC
predicts 1.7 kg N ha−1 year−1 of background N2O emissions, accounting for 15% of the observed emissions. Climate shifts will increase total annual modeled N2O emissions from 15.4 kg N ha−1 to 22.4 kg N ha−1 if current levels of N applications are maintained, or to 21.2 kg N ha−1 if synthetic N applications are reduced to 170 kg N ha−1 to comply with recent EU water quality legislation. Thus the projected increase in N2O emissions due to climate change is far larger than the decrease expected from reduced fertilizer applications. 相似文献
3.
Christine Kreye Klaus Dittert Xunhua Zheng Xu Zhang Shan Lin Hongbin Tao Burkhard Sattelmacher 《Nutrient Cycling in Agroecosystems》2007,77(3):293-304
Lowland rice production is currently facing serious water shortages in numerous Asian countries. In the North China Plain
water limitations are severe. Water-saving rice production techniques are therefore increasingly searched for. Here we present
the first study of trace gas emissions from a water-saving rice production system where soils are mulched and are kept close
to field capacity in order to compare their contribution to global warming with traditional paddy rice. In a two-year field
experiment close to Beijing, CH4 and N2O fluxes were monitored in two forms of the Ground Cover Rice Production System (GCRPS) and in traditional paddy fields using
closed chambers. With paddy rice the observed CH4 emissions were very low, about 0.3 g CH4 m−2 a−1 in 2001 and about 1 g CH4 m−2 a−1 in 2002. In GCRPS, the CH4 emissions were negligible. N2O fluxes in GCRPS were similar, 0.5 to 0.6 g N2O m−2 a−1 in 2001 and 2002, and emission peaks mainly followed fertilizer applications. In paddy rice, N2O fluxes were unexpectedly low throughout the year 2001 (0.03 g N2O m−2 a−1), and in 2002 larger emissions occurred during the drainage period. So with 0.4 g N2O m−2 a−1 the cumulative flux was similar to emissions in GCRPS. Total CO2 equivalent fluxes calculated according to IPCC methodology were tenfold higher in GCRPS compared to paddy in 2001. In 2002,
fluxes from both systems were similar with 175 and 141 g CO2 equivalents m−2 a−1 from GCRPS and paddy.
Burkhard Sattelmacher deceased. 相似文献
4.
According to the revised 1996 IPCC guidelines, several emission factors are needed to calculate national inventories of N2O emissions from agriculture. To estimate the direct N2O emissions from mineral soils, an emission factor of 0.0125 kg N2O-N per kg N applied is currently being used. From recent literature data it was clearly shown that real N2O emissions could differ substantially from this value. Based on the IPCC methodology an inventory of N2O emission from agriculture in Europe (EU-15) has been made. In 1996, the N2O emission was estimated at 672 Gg N2O-N. The N2O emission per country varied between 10 and 177 Gg N2O-N. The N2O emission per ha agricultural land in the various countries varied between 1.7 and 14.2 kg N2O-N ha−1. Highest N2O emissions per ha were found in countries with a high agricultural intensity, such as the Netherlands, Belgium-Luxembourg,
Denmark and Germany. Agricultural soils are a sink for atmospheric methane. An oxidation capacity of 2.5 and 1.5 kg CH4 ha−1 yr−1 was put forward for grasslands and arable land, respectively. Based on land use data of 1993, the CH4 sink of agricultural lands in EU-15 was estimated at 303.5 Gg CH4. In general, it could be concluded that N2O emissions from soils (327 Tg CO2 equivalents) are far more important than its sink function for CH4 (6.3 Tg CO2 equivalents).
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
5.
Fluxes of CH4 and N2O were measured regularly in an agricultural field treated with 280 g m−2 of sewage sludge. In a nearby beech forest N2O and CH4 fluxes were measured in a well-drained (dry) area and in a wet area adjacent to a drainage canal. We observed brief increases
of both CH4 and N2O emissions immediately following soil applications of digested sewage sludge. Cumulated values for CH4 emissions over the course of 328 days after sludge applications indicated a small net source in sludge treated plots (7.6
mg C m−2) whereas sludge-free soil constituted a small sink (-0.9 mg C m−2). The CH4 emission amounted 0.01% of the sludge-C. Extrapolated to current rates of sludge applications in Danish agriculture this
amounts to 0.1% of the total agricultural derived CH4. Sludge applications did not affect cumulated fluxes of N2O showing 312 mg N2O–N m−2 and 304 mg N m−2 with and without sludge, respectively. Four months after the sludge applications a significant effect on CO2 and NO emissions was still obvious in the field, the latter perhaps due to elevated nitrification. Nitrous oxide emission
in the beech forest was about six times smaller (45 mg N m−2) than in the field and independent of drainage status. Methane oxidation was observed all-year round in the forest cumulating
to -225 mg C m−2 and -84 mg C m−2 in dry and wet areas. In a model experiment with incubated soil cores, nitrogen amendment (NH4Cl) and perturbation significantly reduced CH4 oxidation in the forest soil, presumably as a result of increased nitrification activity. Sludge also induced net CH4 production in the otherwise strong CH4 oxidising forest soil. This emphasises the potential for CH4 emissions from sewage sludge applications onto land. The study shows, however, that emissions of N2O and CH4 induced by sewage sludge in the field is of minor importance and that factors such as land use (agriculture versus forest)
is a much stronger controller on the source/sink strengths of CH4 and N2O.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
6.
G.X. Chen G.H. Huang B. Huang K.W. Yu J. Wu H. Xu 《Nutrient Cycling in Agroecosystems》1997,49(1-3):41-45
The closed chamber method was used to measure the N2O and CH4 emissions from rice, maize, soybean and spring wheat fields in Northeast China. Rice field almost did not emit or deposit
N2O in total during flooding period, whereas N2O was substantially emitted during non-flooding period. The annual emission amount of N2O was 1.70 kg N2O ha-1, but that in flooding period was only 0.04 kg N2O ha-1. Daily average and seasonal total CH4 emission in rice field were 0.07 and 7.40 g CH4m-2, respectively. A trade-off between N2O and CH4 emissions from rice field was found. The growth of Azolla in rice field greatly stimulated both N2O and CH4 emissions. Total N2O emissions (270 days) from maize and soybean fields were 7.10 and 3.12 kg N2O ha-1, respectively. The sink function of the uplands monitored as the atmospheric CH4 was not significant.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
7.
Emissions of nitrous oxide (N2O) from managed and grazed grasslands on peat soils are amongst the highest emissions in the world per unit of surface of
agriculturally managed soil. According to the IPCC methodology, the direct N2O emissions from managed organic soils is the sum of N2O emissions derived from N input, including fertilizers, urine and dung of grazing cattle, and a constant ‘background’ N2O emission from decomposition of organic matter that depends on agro-climatic zone. In this paper we questioned the constant
nature of this background emission from peat soils by monitoring N2O emissions, groundwater levels, N inputs and soil NO3
−–N contents from 4 grazed and fertilized grassland fields on managed organic peat soil. Two fields had a relatively low groundwater
level (‘dry’ fields) and two fields had a relatively high groundwater level (‘wet’ fields). To measure the background N2O emission, unfertilized sub-plots were installed in each field. Measurements were performed monthly and after selected management
events for 2 years (2008–2009). On the managed fields average cumulative emission equaled 21 ± 2 kg N ha−1y−1 for the ‘dry’ fields and 14 ± 3 kg N ha−1y−1 for the ‘wet’ fields. On the unfertilized sub-plots emissions equaled 4 ± 0.6 kg N ha−1y−1 for the ‘dry’ fields and 1 ± 0.7 kg N ha−1y−1 for the ‘wet’ fields, which is below the currently used estimates. Background emissions were closely correlated with groundwater
level (R
2 = 0.73) and accounted for approximately 22% of the cumulative N2O emission for the dry fields and for approximately 10% of the cumulative N2O emissions from the wet fields. The results of this study demonstrate that the accuracy of estimating direct N2O emissions from peat soils can be improved by approximately 20% by applying a background emission of N2O that depends on annual average groundwater level rather than applying a constant value. 相似文献
8.
Changsheng Li Yahui Zhuang Meiqio Cao Patrick Crill Zhaohua Dai Steve Frolking Berrien Moore III William Salas Wenzhi Song Xiaoke Wang 《Nutrient Cycling in Agroecosystems》2001,60(1-3):159-175
Nations are now obligated to assess their greenhouse gas emissions under the protocols of Article 4 of the United Nations
Framework Convention on Climate Change. The IPCC has developed `spreadsheet-format' methodologies for countries to estimate
national greenhouse gas emissions by economic sector. Each activity has a magnitude and emission rate and their product is
summed over all included activities to generate a national total (IPCC, 1997). For N2O emissions from cropland soils, field studies have shown that there are important factors that influence N2O emissions at specific field sites that are not considered in the IPCC methodology. We used DNDC, a process-oriented agroecosystem
model, to develop an unofficial national inventory of direct N2O emissions from cropland in China. We assembled county-scale data on soil properties, daily weather, crop areas, N-fertilizer
use, livestock populations (for manure inputs to cropland), and agricultural management for the 2500 counties in mainland
China. Total 1990 cropland area was 0.95 million km2. Total N-fertilizer use in China in 1990 was 16.6 Tg N. The average fertilization rate was 175 kg N ha−1 cropland. One-year simulations with DNDC were run for each crop type in each county to generate estimates of direct N2O emissions from soils. National totals were the sum of results for all crop simulations across all counties. Baseline simulations
estimated that total N2O emission from arable land in China in 1990 was 0.31 Tg N2O-N yr−1. We also ran simulations with zero N-fertilizer input; the difference between the zero-fertilizer and the baseline run is
an estimate of fertilizer-induced N2O emissions. The fertilizer-induced emission was 0.13 Tg N2O-N yr−1, about 0.8% of total N-fertilizer use (lower than the mean but within the IPCC range of 1.25±1.0%). We compared these results
to our estimates of county-scale IPCC methodology emissions. Total emissions were similar but geographical patterns were quite
different.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
Quantifying the Reduction of Greenhouse Gas Emissions as a Resultof Composting Dairy and Beef Cattle Manure 总被引:1,自引:0,他引:1
Greenhouse gas emissions from the agricultural sector can be reduced through implementation of improved management practices.
For example, the choice of manure storage method should be based on environmental decision criteria, as well as production
capacity. In this study, greenhouse gas emissions from three methods of storing dairy and beef cattle manure were compared
during the summer period. The emissions of CH4, N2O and CO2 from manure stored as slurry, stockpile, and compost were measured using a flow-through closed chamber. The largest combined
N2O–CH4 emissions in CO2 equivalent were observed from the slurry storage, followed by the stockpile and lastly the passively aerated compost. This
ranking was governed by CH4 emissions in relation to the degree of aerobic conditions within the manure. The radiative forcing in CO2 equivalent from the stockpiled manure was 1.46 times higher than from the compost for both types of cattle manure. It was
almost twice as high from the dairy cattle manure slurry and four to seven times higher from the beef cattle manure slurry
than from the compost. The potential reduction of GHG was estimated, by extrapolating the results of the study to all of Canada.
By composting all the cattle manure stored as slurry and stockpile, a reduction of 0.70 Tg CO2-eq year−1 would be achieved. Similarly, by collecting and burning CH4 emissions from existing slurry facilities, a reduction of 0.76 Tg CO2-eq year−1 would be achieved. New CH4 emission factors were estimated based on these results and incorporated into the IPCC methodology. For North-America under
cool conditions, the CH4 emission factors would be 45 kg CH4 hd−1 year−1 for dairy cattle manure rather than 36 kg CH4 hd−1 year−1, and 3 kg CH4 hd−1 year−1 for beef cattle manure rather than 1 kg CH4 hd−1 year−1. 相似文献
10.
C. L. van Beek M. Pleijter C. M. J. Jacobs G. L. Velthof J. W. van Groenigen P. J. Kuikman 《Nutrient Cycling in Agroecosystems》2010,86(3):331-340
Intensively managed grasslands on organic soils are a major source of nitrous oxide (N2O) emissions. The Intergovernmental Panel on Climate Change (IPCC) therefore has set the default emission factor at 8 kg N–N2O ha−1 year−1 for cultivation and management of organic soils. Also, the Dutch national reporting methodology for greenhouse gases uses
a relatively high calculated emission factor of 4.7 kg N–N2O ha−1 year−1. In addition to cultivation, the IPCC methodology and the Dutch national methodology account for N2O emissions from N inputs through fertilizer applications and animal urine and faeces deposition to estimate annual N2O emissions from cultivated and managed organic soils. However, neither approach accounts for other soil parameters that might
control N2O emissions such as groundwater level. In this paper we report on the relations between N2O emissions, N inputs and groundwater level dynamics for a fertilized and grazed grassland on drained peat soil. We measured
N2O emissions from fields with different target groundwater levels of 40 cm (‘wet’) and 55 cm (‘dry’) below soil surface in
the years 1992, 1993, 2002, 2006 and 2007. Average emissions equalled 29.5 kg N2O–N ha−1 year−1 and 11.6 kg N–N2O ha−1 year−1 for the dry and wet conditions, respectively. Especially under dry conditions, measured N2O emissions exceeded current official estimates using the IPCC methodology and the Dutch national reporting methodology. The
N2O–N emissions equalled 8.2 and 3.2% of the total N inputs through fertilizers, manure and cattle droppings for the dry and
wet field, respectively and were strongly related to average groundwater level (R
2 = 0.74). We argue that this relation should be explored for other sites and could be used to derive accurate emission data
for fertilized and grazed grasslands on organic soils. 相似文献
11.
Greenhouse gas emissions were measured from tropical peatlands of Kalimantan, Indonesia. The effect of hydrological zone and land-use on the emission of N2O, CH4 and CO2 were examined. Temporal and annual N2O, CH4 and CO2 were then measured. The results showed that the emissions of these gases were strongly affected by land-use and hydrological zone. The emissions exhibited seasonal changes. Annual emission of N2O was the highest (nearly 1.4 g N m–2y–1) from site A-1 (secondary forest), while there was no signi.cant difference in annual N2O emission from site A-2 (paddy field) and site A-3 (rice-soybean rotation field). Multiplying the areas of forest and non-forest in Kalimantan with the emission of N2O from corresponding land-uses, the annual N2O emissions from peat forest and peat non-forest of Kalimantan were estimated as 0.046 and 0.004 Tg N y–1, respectively. The emissions of CH4 from paddy field and non-paddy field were estimated similarly as 0.14 and 0.21 Tg C y–1, respectively. Total annual CO2 emission was estimated to be 182 Tg C y–1. Peatlands of Kalimantan, Indonesia, contributed less than 0.3 of the total global N2O, CO2 or CH4 emission, indicating that the gaseous losses of soil N and C from the study area to the atmosphere were small. 相似文献
12.
Emissions of NH3, N2O and CH4 from dairy cows housed in a farmyard manure tying stall (housing, manure storage, manure spreading) 总被引:2,自引:0,他引:2
Emission measurements from dairy cows housed in a tying stall were carried out with the aim of finding factors that influence
the amount of emissions and means to reduce emissions. All sectors of animal husbandry were investigated. This enabled calculations
of emissions for the whole management system including housing, storage and spreading of manure. Emissions during aerobic
composting and anaerobic stacking of farmyard manure were compared. NH3 and N2O emissions from tying stalls for dairy cows are low (5.8 g NH3 LU−1 d−1, 619.2 mg N2O LU−1 d−1). Methane emissions from the animal housing are mainly caused by enteric fermentation. During storage and after spreading
of farmyard manure substantial differences concerning NH3, N2O and CH4 emissions were observed with composted and anaerobically stacked farmyard manure. The compost emitted more NH3 than the anaerobically stacked farmyard manure. About one third of the NH3 emissions from the anaerobically stacked farmyard manure occurred after spreading. Total N losses were at a low level with
both storage systems. Greenhouse gas emissions (N2O and CH4) were much higher from the anaerobically stacked farmyard manure than from the composted one. As these are ecologically harmful
gases, they have to be considered when judging the form of manure treatment.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
13.
Pascal Boeckx Eline Van Moortel Oswald Van Cleemput 《Nutrient Cycling in Agroecosystems》2001,60(1-3):197-208
In this study N2O emissions from agriculture in Belgium have been split up per agro-pedological region and calculated per farm type. The N2O emissions were calculated according to the `Revised 1996 IPCC guidelines for national greenhouse gas inventories'. Input
data were weighed averages of the N balance of a large number of farms per agro-pedological region and per farm type. As such,
the input data represent a theoretical farm in each agro-pedological region and for each distinguished farm type. In a first
part, N2O emissions were calculated for 10 agro-pedological regions in Belgium. The yearly N2O emissions varied between 225 and 462 kg N2O-N. The highest N2O emissions (around 400 kg N2O-N yr−1) were found in regions with fertile soils, dominated by crop production or a combination of crop production and cattle breeding.
The lowest emissions (around 250 kg N2O-N yr−1) were found in regions with extensive cattle breeding. N2O emissions of 300 ± 15 kg N2O-N yr−1 were found in regions with less extensive cattle breeding or in regions with combinations of cattle, pig and poultry breeding.
The N2O emission per ha varied between 6 and 14 kg N2O-N yr−1. In a second part, N2O emissions were calculated for 12 different farm types. The yearly N2O emissions varied between 273 and 512 kg N2O-N. The highest emissions were found on farms with crop production or a combination of crop production and cattle breeding.
The lowest emissions were found on farms specialised in only one activity of animal breeding. Specialised pig farms and farms
with combinations of cattle caused the greatest threat with respect to N2O releases from agriculture. Their N2O emission per ha was 18–40 kg N2O-N yr−1, which was significantly higher than the average N2O release (10 kg N2O-N yr−1 ha−1) for the other farm types.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
14.
Emission of ammonia (NH3), nitrous oxide (N2O) and methane (CH4) from a dairy hardstanding in the UK
S. Ellis J. Webb T. Misselbrook D. Chadwick 《Nutrient Cycling in Agroecosystems》2001,60(1-3):115-122
Emissions of ammonia (NH3), nitrous oxide (N2O) and methane (CH4) from uncovered yard areas (hardstandings) of a UK dairy farm were measured between October 1997 and August 1999. Measurements
were concentrated after morning milking when the yard had been scraped, and at positions accounting for differences in slurry
coverage and manure type. Over two seasons, the mean NH3 emission from a number of season and position categories on the hardstanding were 0.27 g N m−2 h−1 in winter and spring, 0.45 g N m−2 h−1 in summer when the feeding/loafing area was not included, increasing to 1.51 g N m−2 h−1 when this area was included, and 5.0 g N m−2 h−1 for the feeding/loafing area alone. The feeding/loafing area was close to the slurry lagoon where excreta were continuously
deposited and not scraped to the slurry lagoon, as was the rest of the hardstanding. A diurnal study of emissions in the summer
showed a marked decrease with time after the yard was scraped following the first milking, with emissions increasing again
after evening milking when fresh excreta were deposited. Nitrous oxide emissions were more variable than NH3, with an order of magnitude difference between lowest and highest emissions measured at the same time. Mean N2O emission rates were 3.3 μg N m−2 h−1 in winter and spring, 6.5 μg N m−2 h−1 in summer when the feeding/loafing area was not included, increasing to 7.8 μg N m−2 h−1 when this area was included, and 17.9 μg N m−2 h−1 for the feeding/loafing area alone. Large mean methane emissions were measured, 185 mg C m−2 h−1 in winter and spring, decreasing to 57.3 mg C m−2 h−1 in summer when the feeding/loafing area was not included, increasing to 72.9 mg C m−2 h−1 when this area was included, and 151.2 mg C m−2 h−1 for the feeding/loafing area alone. Therefore in summer, emissions measured directly from a dung pat [0–5 cm] that had not
been scraped from the loafing area were much greater than from scraped hardstanding areas, but in winter there were still
significant emissions from the remaining slurry post-scraping. The experimental design was not sufficient to elucidate the
physico-chemical variables controlling the measured emissions, but the data were put into context by estimating the annual
emission of these pollutant gases from this one dairy farm. These were estimated at 0.43 t NH3-N y−1, 0.3 kg N2O-N y−1 and 1.0 kg CH4-C y−1. Therefore, uncovered farmyard areas that regularly have excreta deposited on them are significant but previously unaccounted
for sources of NH3 loss, less so for N2O and CH4, and require further study to assess the significance of these emission sources within the UK and worldwide.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
15.
Urease and nitrification inhibitors to reduce emissions of CH4 and N2O in rice production 总被引:2,自引:0,他引:2
Xingkai Xu Pascal Boeckx Oswald Van Cleemput Likai Zhou 《Nutrient Cycling in Agroecosystems》2002,64(1-2):203-211
Strategies used to reduce emissions of N2O and CH4 in rice production normally include irrigation management and fertilization. To date, little information has been published on the measures that can simultaneously reduce both emissions. Effects of application of a urease inhibitor, hydroquinone (HQ), and a nitrification inhibitor, dicyandiamide (DCD) together with urea (U) on N2O and CH4 emission from rice growing were studied in pot experiments. These fertilization treatments were carried out in the presence and absence of wheat straw, applied to the soil surface. Without wheat straw addition, in all treatments with inhibitor(s) the emission of N2O and CH4 was significantly reduced, as compared with the treatment whereby only urea was applied (control). Especially for the U+HQ+DCD treatment, the total emission of N2O and CH4 was about 1/3 and 1/2 of that in the control, respectively. In the presence of wheat straw, the total N2O emission from the U+HQ+DCD treatment was about 1/2 of that from the control. The total CH4 emission was less influenced. Wheat straw addition, however, induced a substantial increase in emissions of N2O and CH4. Hence, simultaneous application of organic materials with a high C/N ratio and N-fertilizer (e.g. urea) is not a suitable method to reduce the N2O and CH4 emission. Application of HQ+DCD together with urea seemed to improve the rice growth and to reduce both emissions. The NO3
–-N content of the rice plants and denitrification of (NO3
–+NO2
–)-N might contribute to the N2O emission from flooded rice fields. 相似文献
16.
Annick Goossens Alex De Visscher Pascal Boeckx Oswald Van Cleemput 《Nutrient Cycling in Agroecosystems》2001,60(1-3):23-34
In the following study N2O emissions from 3 different grasslands and from 3 different arable lands, representing major agriculture areas with different
soil textures and normal agricultural practices in Belgium, have been monitored for 1 to 2 years. One undisturbed soil under
deciduous forest was also included in the study. Nitrous oxide emission was measured directly in the field from vented closed
chambers through photo-acoustic infrared detection. Annual N2O emissions from the arable lands ranged from 0.3 to 1.5 kg N ha−1 y−1 and represent 0.3 to 1.0% of the fertilizer N applied. Annual N2O emissions from the intensively managed grasslands and an arable land sown with grass were significantly larger than those
from the cropped arable lands. Emissions ranged from 14 to 32 kg N ha−1 y−1, representing fertilizer N losses between 3 and 11%. At the forest soil a net N2O uptake of 1.3 kg N2O-N ha−1 was recorded over a 2-year period. It seems that the N2O-N loss per unit of fertilizer N applied is larger for intensively managed and heavily fertilized (up to 500 kg N ha−1) grasslands than for arable lands and is substantially larger than the 1.25% figure used for the global emission inventory.
Comparison of the annual emission fluxes from the different soils also indicated that land use rather than soil properties
influenced the N2O emission. Our results also show once again the importance of year-round measurements for a correct estimate of N2O losses from agricultural soils: 7 to 76% of the total annual N2O was emitted during the winter period (October–February). Disregarding the emission during the off-season period can lead
to serious underestimation of the actual annual N2O flux.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
17.
Effect of crop-specific field management and N fertilization on N2O emissions from a fine-loamy soil 总被引:1,自引:0,他引:1
R. Ruser H. Flessa R. Schilling F. Beese J.C. Munch 《Nutrient Cycling in Agroecosystems》2001,59(2):177-191
Agricultural soils are a major source of atmospheric N2O. This study was conducted to determine the effect of different crop-specific field management and N fertilization rates
on N2O emissions from a fine-loamy Dystric Eutrochrept. Fluxes of N2O were measured for two years at least once a week on plots cropped with potatoes (Solanum tuberosum) fertilized with 50 or 150 kg N ha−1 a−1, winterwheat (Triticum aestivum) fertilized with 90 or 180 kg N ha−1 a−1, corn (Zea mays) fertilized with 65 or 130 kg N ha−1 a−1, and on an unfertilized, set-aside soil planted with grass (mainly Lolium perenne and Festuca rubra). The mean N2O emission rate from the differently managed plots was closely correlated to the mean soil nitrate content in the Ap horizon
for the cropping period (April to October, r
2 = 0.74), the winter period (November to March, r
2 = 0.93, one outlier excluded), and the whole year (r
2 = 0.81). N2O emissions outside the cropping period accounted for up to 58% of the annual emissions and were strongly affected by frost-thaw
cycles. There was only a slight relationship between the amount of fertilizer N applied and the annual N2O emission (r
2 = 0.20). The mean annual N2O-N emission from the unfertilized set-aside soil was 0.29 kg ha−1. The annual N2O-N emission from the fertilized crops for the low and the recommended rates of N fertilization were 1.34 and 2.41 kg ha−1 for corn, 2.70 and 3.64 kg ha−1 for wheat, and 5.74 and 6.93 kg ha−1 for potatoes. The high N2O emissions from potato plots were due to (i) high N2O losses from the interrow area during the cropping season and (ii) high soil nitrate contents after the potato harvest. The
reduction of N fertilization (fertilizer was applied in spring and early summer) resulted in decreased N2O emissions during the cropping period. However, the emissions during the winter were not affected by the rate of N fertilization.
The results show that the crop-specific field management had a great influence on the annual N2O emissions. It also affected the emissions per unit N fertilizer applied. The main reasons for this crop effect were crop-specific
differences in soil nitrate and soil moisture content.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
18.
Methane and Nitrous Oxide Emissions from Rice Field and Related Microorganism in Black Soil, Northeastern China 总被引:5,自引:0,他引:5
Jin Yue Yi Shi Wei Liang Jie Wu Chenrui Wang Guohong Huang 《Nutrient Cycling in Agroecosystems》2005,73(2-3):293-301
Methane (CH4) and nitrous oxide (N2O) emissions from rice field in black soil were measured in situ by using static chamber techniques during crop growth season in 2001. The experiment fields were divided into three plots
for three different treatments, one with continuous flooded and applying urea (CU), one with continuous flooded and applying
slow-releasing urea (CS), and one with intermittent irrigation and applying urea (IU). Under the same fertilization application,
compared with continuous flooded, intermittent irrigation can significantly reduce CH4 emission and increase N2O emission. But, integrated global warming potentials (GWPS) of CH4 and N2O emission were reduced greatly, while rice yield was not affected. So, the intermittent irrigation is an effective measure
to reduce greenhouse gas emissions from paddy fields. The amount of CH4 emission during rice-growing season for the three treatments was all much lower than that from any other region in China.
There was a trade-off relationship between CH4 and N2O emissions. We also measured the numbers of methanogens, methanotrophs, nitrifiers and denitrifers from rice field at various
growth stages in 2001. Bacteria populations were estimated by the most probable number (MPN) method. Regression analyses show
CH4 emissions were closely related to methanogens population for all the three treatments. There was a positive correlation between
denitrifiers population level and N2O emission in the treatment of IU. 相似文献
19.
To better understand the effects of increased N input and dry periods on soil nitrous oxide (N2O) emission, we examined a unique data-set of weather, soil microclimate, N input, and N2O emissions (using the eddy covariance method), measured at a fertilized grassland over the period 2003–2008. We found that
the N2O emission (11.5 kg N ha−1 year−1), the ratio of N2O emission to N input (3.4), and the duration of elevated N2O flux (57 days) in 2003 were about two times greater than those of the following years. 2003 had the highest annual N input
(343 kg N ha−1 year−1) which exceeded the agronomical requirements for Irish grasslands (up to 306 kg ha−1 year−1). In the summer of 2003, the site had a significantly higher soil temperature, lower WFPS and lowest rainfall of all years.
Large N2O emission events followed rainfall after a long dry period in the summer of 2003, attributed to dominant nitrification processes.
Furthermore, in the non summer periods, when temperature was lower and WFPS was higher and when there were prior N applications,
lower N2O emissions occurred and were attributed to dominant denitrification processes. Throughout the study period, the N input and
soil dryness related factors (duration of WFPS under 50%, summer average WFPS, and low rainfall) showed exponential relationships
with N2O emission and the ratio of N2O emission to N input. Based on these findings, we infer that the observed anomalously high N2O emission in 2003 may have been caused by the combined effects of excess N input above the plant uptake rate, elevated soil
temperature, and N2O flux bursts that followed the rewetting of dry soil after an unusually long dry summer period. These results suggest that
high N input above plant uptake rate and extended dry periods may cause abnormal increases in N2O emissions. 相似文献
20.
Rice fields are either continuously flooded or drained in China in the winter (non-rice growth season). Due to great spatial variation of precipitation and temperature, there is a spatial variation of soil moisture in the fields under drained conditions during the winter season. The effect of water regime in winter on CH4 emissions during the following rice growing period and their regional variation were investigated. Soil moisture in the winter was simulated by DNDC model with daily precipitation and temperature as model inputs. Under the same management during the rice growing period, CH4 emissions was higher from rice fields flooded, compared to those from fields drained during winter. CH4 emission from rice fields correlated significantly with simulated soil moisture and with mean precipitation of the preceding winter season. Spatial variation of precipitation in winter and corresponding variations of soil moisture regimes control the regional and annual variation of CH4 emissions from rice fields in China. Keeping soils drained as much as possible during winter seems to be a feasible option to reduce CH4 emissions during the following rice growing seasons. 相似文献