[Effects of the Veterinary Antibiotic Sulfamethazine on NO Emissions and the Associated Microbiological Mechanism in a Rice Field].

Veterinary antibiotics can enter into croplands with animal excrement and can have effects on nitrification and denitrification processes in the agricultural soils. A field experiment was conducted to evaluate the effect of sulfamethazine (SMZ) on NO emissions, nitrification, denitrification, and related functional gene abundances within a paddy field. Five treatments were used in the experiment, namely, no fertilizer and no antibiotics applied (CK), and pig manure used as basal fertilizer plus urea applied as topdressing with the addition of 0, 5, 15, and 30 mg·kg SMZ (SMZ0, SMZ5, SMZ15, and SMZ30, respectively).

[Assessment of Gaseous Nitrogen (NH and NO) Mitigation After the Application of a Range of New Nitrogen Fertilizers in Summer Maize Cultivation].

In order to evaluate the potential of a range of new nitrogen fertilizers in comparison with the conventional fertilization to mitigate ammonia (NH) and nitrous oxide (NO) emissions, a field experiment was conducted to investigate NH volatilization and NO emissions from the summer maize field and the relevant driving factors under the different nitrogen fertilizer treatments. Five new varieties of nitrogen fertilizers including the urea ammonium (UA), stability urea with dicyandiamide and hydroquinone (UHD), sulfur coated urea (SCU), urea formaldehyde compound fertilizer (UF) and organic fertilizer (OF) were applied in this experiment, and conventional fertilization (compound fertilizer + urea, CK) was used as the control. The nitrogen amount of 300 kg·hm was applied in all treatments.

[Nitrogen Loss Through Different Ways in Cropland Under Conventional Fertilization: An In-situ Study of Summer Maize Season in the Middle and Lower Reaches of the Yangtze River].

In order to better understand the characteristics of nitrogen loss through different pathways under conventional fertilization conditions, a field experiment was conducted to investigate the variations of N2O emission, NH3 volatilization, N losses through surface runoff and leaching caused by the application of nitrogen fertilizers during summer maize growing season in the Middle and Lower reaches of the Yangtze River, China. Our results showed that when compound fertilizer was used as basal fertilizer at the nitrogen rate of 150 kg.hm-2, and urea with the same level of fertilizing as topdressing, the N2O emission coefficient in the entire growing season was 3.

[Soil biochemical characteristics in different ecological systems and their relationships with soil respiration and N2O emission].

The biochemical characteristics of soil in different ecological system and their effects on soil respiration (CO2) and nitrous oxide (N2O) emission were investigated by an indoor incubation method. The results showed that the biochemical characteristics of soils in the different ecosystems and CO2 and N2O emissions from different soils greatly varied with each other. In general, the highest abundance of bacteria was found in the orchard soil, the highest abundance of actinomycetes occurred in the meadows and the highest abundance of fungi appeared in the woodlands.

[Effects of typical herbicides on soil respiration and N2O emissions from soil added with different nitrogen fertilizers].

To investigate the effects of typical herbicides on soil respiration and N2O emissions from soil added with different nitrogen fertilizers, a laboratory incubation experiment was carried out using a modified gas chromatograph (Agilent 4890D) method. The results showed that with (NH4)2SO4 amendment, soil respiration and N2O emissions from the Atrazine and Paraquat treatments had no significant difference in comparison to the control (P > 0.05).

[Impacts of enhanced UV-B radiation on respiration rate, CH4 and N2O emission fluxes from rice paddy].

To investigate the impacts of enhanced UV-B radiation on respiration rate, CH4 and N2O emission fluxes from soil-rice system, outdoor pot experiment was carried out during the rice growing season in 2004. The enhanced UV-B radiation treatments were simulated by a 20% increase in its intensity. The gas emission fluxes were measured by static chamber-gas chromatograph method.

[Emission inventory of greenhouse gases from agricultural residues combustion: a case study of Jiangsu Province].

Burning of agricultural crop residues was a major source greenhouse gases. In this study, the proportion of crop straws (rice, wheat, maize, oil rape, cotton and soja) in Jiangsu used as household fuel and direct open burning in different periods (1990-1995, 1996-2000, 2001-2005 and 2006-2008) was estimated through questionnaire. The emission factors of CO2, CO, CH4 and NO20 from the above six types of crop straws were calculated by the simulated burning experiment.

[Effects of elevated ultraviolet-B radiation on the chemical composition of wheat straw and the N2O emission from soil amended with the straw].

An outdoor experiment was carried out to investigate the effects of elevated ultraviolet-B radiation on the chemical composition of wheat straw, and an indoor incubation test was conducted to study the effects of the amendment of the straw on soil N2O emission. Outdoor experiment showed that the enhanced UV-B decreased the aboveground biomass of wheat, increased the lignin and total N contents of wheat straw by 94.2% and 12.

[Isolation of heterotrophic nitrifiers/aerobic denitrifiers and their roles in N2O production for different incubations].

Soil microorganisms are important sources of N2O for the atmosphere. Peak emissions of N2O are often observed after wetting of soil. The simultaneous heterotrophic nitrifying and aerobic denitrifying bacteria with respect to N2O emission were studied to obtain more information about the microbiologcal aspects of peak emissions.

[Influence of enhanced UV-B radiation on respiration rate and N2O emission from soil-winter wheat system].

To investigate the impact of enhanced UV-B radiation on respiration rate and N2O emission from soil-winter wheat system, outdoor pot experiments with simulating 20% supplemental of UV-B were conducted, and static dark chamber-gas chromatograph method were used. Results indicated that the enhanced UV-B radiation did not change the seasonal pattern of respiration rate and N2O emission. Enhanced UV-B radiation declined the rate of soil-winter wheat system's respiration but had no significant impact on N2O emission in turning-green stage.

[Study on mechanism of enhanced UV-B radiation influencing on N2O emission from soil-winter wheat system].

To study the influencing mechanisms of enhanced UV-B radiation on the emission of N20 from soil-wheat system, outdoor pot experiments with simulating 20% supplemental level of UV-B were conducted. Results indicate that the enhanced UV-B had no significant impact on the emission of N20 from soil-wheat system in turning- green stage, but declined the N2O flux and the rate of the system's respiration in elongation stage. The impact mechanisms of enhanced UV-B radiation on the N2O flux were to directly change the nitrogen metabolism process of wheat plant, such as significantly increasing soluble protein, total nitrogen and total phosphorus in wheat leaves.