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《Communications in Soil Science and Plant Analysis》2012,43(19-20):3181-3193
A laboratory incubation was conducted to evaluate nitrous oxide (N2O) production during nitrification and the effect of a nitrification inhibitor on N2O production from different profiles in a Japanese orchard Andosol. Soils were collected from five profiles: A1, A2, Bw1, Bw2, and BC. The soils were treated with ammonium sulfate at the rate of 200 mg N kg?1 with or without dicyandiamide (DCD) and incubated under aerobic conditions for 32 days. The net nitrification rate without DCD during the first 8 days was greater in the surface soils than in the subsurface soils. Accordingly, the surface soils showed a greater cumulative N2O production than the subsurface soils. Application of DCD significantly reduced the nitrification rate and thus N2O production from any depths of soils by 33.8 to 62.9%. Our study showed that substantial N2O was produced from the subsurface soil, although the amount was less than from the surface soils. 相似文献
54.
不同氮肥处理春玉米温室气体的排放 总被引:6,自引:1,他引:5
春玉米种植过程中会造成直接和间接的温室气体排放。该文采用生命周期的方法综合评估了不同施肥处理下的温室气体排放,目的是筛选出既能保证产量和经济效益,又能有效减排的措施。4种不同的施肥处理包括:当地传统施肥方式、尿素处理、硫包衣尿素、尿素添加双氰胺处理。采用静态箱-气相色谱法连续监测土壤 N2O排放,并计算了不同肥料处理的N2O排放总量;计算了肥料生产、运输、农田耕作管理能源消耗、种子生产等的温室气体排放,计算了春玉米全生命周期中温室气体排放总量、单位产量、万元产出的温室气体排放量。结果表明,不同处理施肥造成的N2O排放量、全生命周期中温室气体排放总量、单位产量排放强度和净收益排放强度的排序均为传统施肥处理>尿素处理>尿素添加双氰胺处理>硫包衣尿素处理。传统施肥处理的N2O排放总量极显著高于其他3个处理(P<0.01);硫包衣尿素处理的N2O排放总量显著低于尿素处理(P<0.05),与尿素添加双氰胺处理无显著差异(P>0.05)。不同处理的全生命周期排放总量、单位玉米产量排放量和万元净产值排放量变化范围分别是2.56~4.11 t/(hm2·a)、216.6~364.1 kg/t和1.15~2.19 t/万元。和传统施肥处理相比,硫包衣尿素处理可分别降低温室气体(greenhouse Gas,GHG)排放总量、单位玉米产量排放和万元净产值碳排放37.8%、40.5%和47.3%,尿素添加双氰胺处理可降低36.5%、38.6%和45.9%。化肥尤其是氮肥的生产在春玉米种植过程中对碳足迹的贡献最大,占42.4%~55.0%;玉米生产过程中的N2O排放次之,占20.8%~26.1%。在保证粮食产量和经济效益的前提下,硫包衣尿素处理和尿素添加双氰胺处理2种施肥方式具有较低的碳排放强度,可作为当地较为合理的施肥方式进行推广。 相似文献
55.
内皮素对肺动脉高压综合征肉鸡的影响 总被引:9,自引:1,他引:9
利用高能日粮常规饲养大群艾维因肉鸡的方法,获得自然肺动脉高压综合征(PHS)肉鸡病例。应用放 射免疫分析方法,分别测定了2~6 周龄正常组和肺动脉高压(PH)组肉鸡血浆及心、肝、肺、肾等组织中内皮素(endothelin-1,ET-1)的含量,并测定了腹水心脏指数(AHI)和平均肺动脉压(mPAP),同时还应用硝酸还原酶法 测定了血浆中一氧化氮(NO)、一氧化氮合酶(NOS)水平。结果显示:PH组AHI、mPAP极显著高于正常组(P<0.01); 从 3周龄开始,PH组ET-1水平开始显著或极显著高于正常组 相似文献
56.
Jining Zhang Huifeng Sun Jia Ma Xianxian Zhang Cong Wang Sheng Zhou 《Soil Use and Management》2023,39(2):729-741
Intensive vegetable crop systems are rapidly developing, with consequences for greenhouse gas (GHGs) emissions, nitrogen leaching and soil carbon. We undertook a field trial to explore the effect of biochar application (0, 10, 20 and 40 t ha−1) on these factors in lettuce, water spinach and ice plant rotation. Our results show that the 20 and 40 t ha−1 soil treatments resulted in the SOC content being 26.3% and 29.8% higher than the control (0 t ha−1), respectively, with significant differences among all treatments (p < .05). Biochar application caused N2O emissions to decrease during the lettuce and water spinach seasons, by 1.5%–33.6% and 12.4%–40.5%, respectively, compared the control, with the 20 t ha−1 application rate resulting in the lowest N2O emissions. Biochar also decreased the dissolved nitrogen (DN) concentration in leachate by 9.8%–36.2%, following a 7.3%–19.9% reduction in dissolved nitrogen in the soil. Similarly, biochar decreased the nitrate (NO3−) concentrations in leachate by 3.9%–30.2%, following a 3.8%–16.7% reduction in the soil nitrate level. Overall, straw biochar applied at rate of 20 t ha−1 produced the lowest N2O emissions and N leaching, while, increasing soil carbon. 相似文献
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Climate change associated with greenhouse gas (GHG) emissions may have important implications for Europe's grasslands. Projected scenarios indicate that increased temperatures and CO2 concentrations have the potential to increase herbage growth and to favour legumes more than grasses, but changes in seasonal precipitation would reduce these benefits particularly in areas with low summer rainfall. Further implications for grasslands may arise from increased frequency of droughts, storms and other extreme events. Potential farm-scale adaptive responses to climate change are identified. Grassland agriculture also contributes to GHG emissions, particularly methane and nitrous oxide, and management of grassland affects net carbon balances and carbon sequestration. Management options are identified for mitigating grassland's contribution to GHG emissions which need to be developed in a holistic way that also considers other pressures. 相似文献
59.
Poly(1-oxo-2-phenyltrimethylene) was successfully synthesized in the presence of palladium acetate and rare earth acetate
RE(OAc)3 (RE=Pr, Nd, Eu, Dy, Ho) multiplex catalyst system. The final products were characterized by elemental analysis, nuclear magnetic
resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). The effects of various reaction parameters including molar
ratio of rare earth/Pd2+, methanol usage, 2,2-bipyridyl,p-toluensulfonic acid, andp-benzoquinone were studied in detail, and the influence of different rare earths on the copolymerization was also discussed.
It is found that the rare earths have favorable co-catalytic properties and palladium-rare earth multiplex catalyst showed
higher catalytic activity than palladium catalyst in the copolymerization of carbon monoxide (CO) and styrene (ST). 相似文献