Concentrations of atmospheric nitrous oxide (N2O), a potent greenhouse gas, have been continuously increasing, and cropland soils are one of the largest sources of N2O. Variations in environmental and anthropogenic ...Concentrations of atmospheric nitrous oxide (N2O), a potent greenhouse gas, have been continuously increasing, and cropland soils are one of the largest sources of N2O. Variations in environmental and anthropogenic factors have substantial impacts on both the frequency and magnitude of N2O emissions. Based on measurements from a wheat-maize system in the North China Plain, the authors parameterized the Agricultural Production Systems Simulator (APSIM) model, which was initially developed in Australia, for simulating N2O emissions under different agricultural management practices. After calibrating one of the key parameters -- the fraction of N2O lost in nitrification (k2) -- the results showed that the model successfully captured the daily N2O fluxes under different nitrogen fertilization treatments, but underestimated some large peak fluxes. By pooling all data together, the calibrated APSIM model also performed well in representing cumulative N2O emissions under various treatments at annual and finer (monthly and daily) time scales.展开更多
Measurements of nitrous oxide emission from agricultural lands were conducted. The results show that nitrous oxide fluxes on several soils are at the range of 2-60 μg . N / m2 h. Factors influencing the production ra...Measurements of nitrous oxide emission from agricultural lands were conducted. The results show that nitrous oxide fluxes on several soils are at the range of 2-60 μg . N / m2 h. Factors influencing the production rates of nitrous oxide from the soils, such as soil temperature, soil moisture and fertilization, are discussed. The calculated amount of nitrous oxide emission from China farmlands is 9.8 × 107 Kg . N per year, which accounts for about 10% of the total source strength in China areas.展开更多
Significance of nitrous oxide in atmospheric chemistry is reviewed briefly. Background concentration of N2O at Wudaoliang in Qinghai Province of Western China has been measured by collecting gas samples and analysing ...Significance of nitrous oxide in atmospheric chemistry is reviewed briefly. Background concentration of N2O at Wudaoliang in Qinghai Province of Western China has been measured by collecting gas samples and analysing them with electron capture-gas chromatography. The atmospheric concentration fluctuates in the range of 303-315 ppb with the mean value of 308 ppb. The emission rate of N2O in agriculture region of Northern China has been studied primarily. Fertilization, rain and temperature of soil appear conductible to N2O emission. The interactions between greenhouse effect and N2O emission have been discussed. The catalytic action of N2O in stratospheric ozone depletion processes and the effect of high N2O concentration on ozone depletion in stratosphere have been considered and discussed.展开更多
Maize ( Zea mays L.), a staple crop in the North China Plain, contributing substantially to agricultural nitrous oxide (N 2 O) emissions in this region. Many studies have focused on various agricultural management mea...Maize ( Zea mays L.), a staple crop in the North China Plain, contributing substantially to agricultural nitrous oxide (N 2 O) emissions in this region. Many studies have focused on various agricultural management measures to reduce N 2 O emissions. However, few have investigated soil N 2 O emissions in intercropping systems. In the current study, we investigate whether maize-soybean intercropping treatments could reduce N 2 O emission rates. Two differently configured maize-soybean intercropping treatments, 2:2 intercropping (two rows of maize and two rows of soybean, 2M2S) and 2:1 intercropping (two rows of maize and one row of soybean, 2M1S), and monocultured maize (M) and soybean (S) treatments were performed using a static chamber method. The results showed no distinct yield advantage for the intercropping systems. The total N 2 O production from the various treatments was 0.15 ± 0.04–113.85 ± 12.75 µg m −2 min −1 . The cumulative N 2 O emission from the M treatment was 16.9 ± 2.3 kg ha −1 over the entire growing season (three and a half months), which was significantly higher ( P < 0.05) than that of the 2M2S and 2M1S treatments by 36.6% and 32.2%, respectively. Two applications of nitrogen (N) fertilizer (as urea) at 240 kg N ha −1 each induced considerable soil N 2 O fluxes. Short-term N 2 O emissions (within one week after each of the two N applications) accounted for 74.4%–83.3% of the total emissions. Soil moisture, temperature, and inorganic N were significantly correlated with soil N 2 O emissions ( R 2 = 0.246–0.365, n = 192, P < 0.001). Soil nitrate (NO − )3 and moisture decreased in the intercropping treatments during the growing season. These results indicate that maize-soybean intercropping can reduce soil N 2 O emissions relative to monocultured maize.展开更多
A regional nitrogen cycle model, named IAP-N, was designed for simulating regional nitrogen (N) cycling and calculating N fluxes flowing among cultivated soils, crops, and livestock, as well as human, atmospheric an...A regional nitrogen cycle model, named IAP-N, was designed for simulating regional nitrogen (N) cycling and calculating N fluxes flowing among cultivated soils, crops, and livestock, as well as human, atmospheric and other systems. The conceptual structure and calculation methods and procedures of this model are described in detail. All equations of the model are presented. In addition, definitions of all the involved variables and parameters are given. An application of the model in China at the national scale is presented. In this example, annual surpluses of consumed synthetic N fertilizer; emissions of nitrous oxide (N2O), ammonia (NH3) and nitrogen oxide (NOx); N loss from agricultural lands due to leaching and runoff; and sources and sinks of anthropogenic reactive N (Nr) were estimated for the period 1961-2004. The model estimates show that surpluses of N fertilizer started to occur in the mid 1990s and amounted to 5.7 Tg N yr^-1 in the early 2000s. N20 emissions related to agriculture were estimated as 0.69 Tg N yr^-1 in 2004, of which 58% was released directly from N added to agricultural soils. Total NH3 and NOx emissions in 2004 amounted to 4.7 and 4.9 Tg N yr^-1, respectively. About 3.9 Tg N yr^-1 of N was estimated to have flowed out of the cultivated soil layer in 2004, which accounted for 33% of applied synthetic N fertilizer. Anthropogenic Nr sources changed from 2.8 (1961) to 28.1 Tg N yr^-1 (2004), while removal (sinks) changed from to 2.1 to 8.4 Tg N yr^-1. The ratio of anthropogenic Nr sources to sinks was only 1.4 in 1961 but 3.3 in 2004. Further development of the IAP-N model is suggested to focus upon: Ca) inter-comparison with other regional N models; (b) overcoming the limitations of the current model version, such as adaptation to other regions, high-resolution database, and so on; and (c) developing the capacity to estimate the safe threshold of anthropogenic Nr source to sink ratios.展开更多
Within a LIFE+ project IPNOA (improved flux prototype for n2o emission from agriculture), LIFE11 ENV/IT/302 is a mobile prototype was developed to evaluate at field scale N20 emissions using a fast chamber techniqu...Within a LIFE+ project IPNOA (improved flux prototype for n2o emission from agriculture), LIFE11 ENV/IT/302 is a mobile prototype was developed to evaluate at field scale N20 emissions using a fast chamber technique. Main challenge was to develop a mobile system capable of moving on various field surfaces, equipped with very reliable N20 gas analyser (Los Gatos Research Inc.), electrically autonomous (with batteries) and enough robust to face up to field conditions. In this paper, we report the major features of this prototype studied during two field campaigns. The N20 flux IPNOA prototype was compared with other methodological implementations: first, during an INGOS (integrated non-CO2 greenhouse gas observing systems) campaign on a grazed grassland at Easter Bush (Scotland) by Eddy correlation method, and then after on an arable crop at Grignon (France) using automatic and manual chambers fitted with QC-TILDAS (Quantum Cascade Tunable Infrared Laser Differential Absorption Spectrometer, Aerodyne Research Inc.), with the 46C model of thermo-instrument analyser or with a GC (gas chromatography) analysis.展开更多
基金supported by the National Natural Science Foundation of China[grant number 41590875]
文摘Concentrations of atmospheric nitrous oxide (N2O), a potent greenhouse gas, have been continuously increasing, and cropland soils are one of the largest sources of N2O. Variations in environmental and anthropogenic factors have substantial impacts on both the frequency and magnitude of N2O emissions. Based on measurements from a wheat-maize system in the North China Plain, the authors parameterized the Agricultural Production Systems Simulator (APSIM) model, which was initially developed in Australia, for simulating N2O emissions under different agricultural management practices. After calibrating one of the key parameters -- the fraction of N2O lost in nitrification (k2) -- the results showed that the model successfully captured the daily N2O fluxes under different nitrogen fertilization treatments, but underestimated some large peak fluxes. By pooling all data together, the calibrated APSIM model also performed well in representing cumulative N2O emissions under various treatments at annual and finer (monthly and daily) time scales.
文摘Measurements of nitrous oxide emission from agricultural lands were conducted. The results show that nitrous oxide fluxes on several soils are at the range of 2-60 μg . N / m2 h. Factors influencing the production rates of nitrous oxide from the soils, such as soil temperature, soil moisture and fertilization, are discussed. The calculated amount of nitrous oxide emission from China farmlands is 9.8 × 107 Kg . N per year, which accounts for about 10% of the total source strength in China areas.
文摘Significance of nitrous oxide in atmospheric chemistry is reviewed briefly. Background concentration of N2O at Wudaoliang in Qinghai Province of Western China has been measured by collecting gas samples and analysing them with electron capture-gas chromatography. The atmospheric concentration fluctuates in the range of 303-315 ppb with the mean value of 308 ppb. The emission rate of N2O in agriculture region of Northern China has been studied primarily. Fertilization, rain and temperature of soil appear conductible to N2O emission. The interactions between greenhouse effect and N2O emission have been discussed. The catalytic action of N2O in stratospheric ozone depletion processes and the effect of high N2O concentration on ozone depletion in stratosphere have been considered and discussed.
基金supported by the National Key Technology R&D Program of China(Nos.2011BAD-16B15 and 2012BAD14B03)the Fundamental Research Funds for Rubber Research Institute,Chinese Academy of Tropical Agricultural Sciences(No.1630022014019)
文摘Maize ( Zea mays L.), a staple crop in the North China Plain, contributing substantially to agricultural nitrous oxide (N 2 O) emissions in this region. Many studies have focused on various agricultural management measures to reduce N 2 O emissions. However, few have investigated soil N 2 O emissions in intercropping systems. In the current study, we investigate whether maize-soybean intercropping treatments could reduce N 2 O emission rates. Two differently configured maize-soybean intercropping treatments, 2:2 intercropping (two rows of maize and two rows of soybean, 2M2S) and 2:1 intercropping (two rows of maize and one row of soybean, 2M1S), and monocultured maize (M) and soybean (S) treatments were performed using a static chamber method. The results showed no distinct yield advantage for the intercropping systems. The total N 2 O production from the various treatments was 0.15 ± 0.04–113.85 ± 12.75 µg m −2 min −1 . The cumulative N 2 O emission from the M treatment was 16.9 ± 2.3 kg ha −1 over the entire growing season (three and a half months), which was significantly higher ( P < 0.05) than that of the 2M2S and 2M1S treatments by 36.6% and 32.2%, respectively. Two applications of nitrogen (N) fertilizer (as urea) at 240 kg N ha −1 each induced considerable soil N 2 O fluxes. Short-term N 2 O emissions (within one week after each of the two N applications) accounted for 74.4%–83.3% of the total emissions. Soil moisture, temperature, and inorganic N were significantly correlated with soil N 2 O emissions ( R 2 = 0.246–0.365, n = 192, P < 0.001). Soil nitrate (NO − )3 and moisture decreased in the intercropping treatments during the growing season. These results indicate that maize-soybean intercropping can reduce soil N 2 O emissions relative to monocultured maize.
文摘A regional nitrogen cycle model, named IAP-N, was designed for simulating regional nitrogen (N) cycling and calculating N fluxes flowing among cultivated soils, crops, and livestock, as well as human, atmospheric and other systems. The conceptual structure and calculation methods and procedures of this model are described in detail. All equations of the model are presented. In addition, definitions of all the involved variables and parameters are given. An application of the model in China at the national scale is presented. In this example, annual surpluses of consumed synthetic N fertilizer; emissions of nitrous oxide (N2O), ammonia (NH3) and nitrogen oxide (NOx); N loss from agricultural lands due to leaching and runoff; and sources and sinks of anthropogenic reactive N (Nr) were estimated for the period 1961-2004. The model estimates show that surpluses of N fertilizer started to occur in the mid 1990s and amounted to 5.7 Tg N yr^-1 in the early 2000s. N20 emissions related to agriculture were estimated as 0.69 Tg N yr^-1 in 2004, of which 58% was released directly from N added to agricultural soils. Total NH3 and NOx emissions in 2004 amounted to 4.7 and 4.9 Tg N yr^-1, respectively. About 3.9 Tg N yr^-1 of N was estimated to have flowed out of the cultivated soil layer in 2004, which accounted for 33% of applied synthetic N fertilizer. Anthropogenic Nr sources changed from 2.8 (1961) to 28.1 Tg N yr^-1 (2004), while removal (sinks) changed from to 2.1 to 8.4 Tg N yr^-1. The ratio of anthropogenic Nr sources to sinks was only 1.4 in 1961 but 3.3 in 2004. Further development of the IAP-N model is suggested to focus upon: Ca) inter-comparison with other regional N models; (b) overcoming the limitations of the current model version, such as adaptation to other regions, high-resolution database, and so on; and (c) developing the capacity to estimate the safe threshold of anthropogenic Nr source to sink ratios.
文摘Within a LIFE+ project IPNOA (improved flux prototype for n2o emission from agriculture), LIFE11 ENV/IT/302 is a mobile prototype was developed to evaluate at field scale N20 emissions using a fast chamber technique. Main challenge was to develop a mobile system capable of moving on various field surfaces, equipped with very reliable N20 gas analyser (Los Gatos Research Inc.), electrically autonomous (with batteries) and enough robust to face up to field conditions. In this paper, we report the major features of this prototype studied during two field campaigns. The N20 flux IPNOA prototype was compared with other methodological implementations: first, during an INGOS (integrated non-CO2 greenhouse gas observing systems) campaign on a grazed grassland at Easter Bush (Scotland) by Eddy correlation method, and then after on an arable crop at Grignon (France) using automatic and manual chambers fitted with QC-TILDAS (Quantum Cascade Tunable Infrared Laser Differential Absorption Spectrometer, Aerodyne Research Inc.), with the 46C model of thermo-instrument analyser or with a GC (gas chromatography) analysis.