节能减排视角下我国农村节能灯的推广研究

通过对湖南省部分农村地区节能灯使用现状的调查研究,分析了农村地区所出现的节能灯“不经济、不节电、不环保”等问题出现的原因,探讨了制约”白炽灯淘汰难、节能灯推广难”的障碍,提出了相应的解决策略。     

Efficacy of probiotics from anaerobic microflora with prebiotics on growth performance and noxious gas emission in growing pigs

We investigated the effect of probiotics from anaerobic microflora with prebiotics (synbiotics) on growth performance, noxious gas emission and fecal pathogenic bacteria populations in growing pigs. The basal diet, which contained approximately 25% corn, 24% whey, 12% wheat and 12% soybean meal, was supplemented alternatively with 0.15% antibiotics (US diet), prebiotics and 0.2% probiotics from anaerobic bacteria (BS diet), yeast (YS diet), mold (MS diet) or compounds (CS diet). One hundred and fifty pigs were fed an experimental diet for 15 days. Although the growth performance was not affected by supplemental synbiotics, the BS group showed higher dry matter and crude protein digestibility. The BS group decreased fecal ammonia and amine gas emissions, and increased fecal acetate gas emission compared with the US group. All synbiotics groups decreased in fecal propionate gas emission. Fecal Escherichia coli population was lower in the synbiotics groups than in the US group. Therefore, the results of the present study suggest that synbiotics exert similar effects with antibiotics on the nutrient digestibility and fecal microflora composition in growing pigs. Moreover, synbiotics can also decrease the fecal noxious gas emission in growing pigs.     

STATIC AND DYNAMIC 18FDG‐PET IN NORMAL HISPANIOLAN AMAZON PARROTS (AMAZONA VENTRALIS)

Positron emission tomography (PET) is often used to stage and monitor human cancer and has recently been used in a similar fashion in veterinary medicine. The most commonly used radiopharmaceutical is 2‐Deoxy‐2‐[¹⁸F]‐Fluoro‐d ‐glucose (¹⁸F‐FDG), which is concentrated and trapped within cells that use glucose as their energy substrate. We characterized the normal distribution of ¹⁸F‐FDG in 10 healthy Hispaniolan Amazon parrots (Amazona ventralis) by performing whole body PET scans at steady state, 60 min after injection. Significant variability was found in the intestinal activity. Avian species are known to reflux fluid and electrolytes from their cloaca into their colon. To evaluate reflux as the cause of variability in intestinal distribution of ¹⁸F‐FDG, dynamic PET scans were performed on the coelomic cavity of six Hispaniolan Amazon parrots from time 0 to 60 min postinjection of radiotracer. Reflux of radioactive material from the cloaca into the colon occurred in all birds to varying degrees and occurred before 60 min. To evaluate the intestinal tract of clinical avian patients, dynamic scans must be performed starting immediately after injection so that increased radioactivity due to metabolism or hypermetabolic lesions such as cancer can be differentiated from increased radioactivity due to reflux of fluid from the cloaca.     

施肥与大气环境质量——论施肥对环境的影响(1)

无机肥和有机肥都是人类可持续发展不可或缺的资源,只要科学使用不会对环境和生态造成负面影响。不良施肥对大气环境的威胁主要来自有机肥,过量使用有机肥可促进土壤中CO2和CH4的排放;有机肥和畜禽粪肥堆放场地有大量氨气污染,有机物的焚烧可直接向大气排放大量的CO2、CH4及固体微粒,使城乡空气严重污染。有机肥和无机N肥的过量使用,都会导致土壤N素积累。土壤中N素的反硝化作用产生N2O, NOx 的排放。避免有机肥和N肥过量,禁止焚烧有机物,覆盖有机肥和畜禽粪肥堆放场,控制反硝化作用,以减少负面效应,保护大气环境质量。     

本质素对土壤N、P转化及玉米产量的影响

研究造纸黑液中提取的木质素对土壤N、P转化及其对玉米生长和产量的影响结果表明,木质素可减缓NH4+向NO3氧化,且随其施用量的增加效果更显著.木质素与磷酸二铵混合施用效果最佳,其次为硫酸铵＞尿素.在30℃温度下培养27d,施用量为2%和5%的木质素可分别减少施尿素土壤N2O释放83%和96%;而施磷酸二铵的土壤则分别减少83%和93%.施用木质素可促进难溶性P的溶解,对作物生长极为有利.玉米盆栽试验中施用木质素的根系较发达、粗壮,平均株高、地上部和地下部的鲜物质量和干物质量均高于不施木质素的处理.木质素用量为50μg/g和200μg/g时玉米籽粒产量分别提高4.2%和18.8%.     

Methane emissions from stems of Fraxinus mandshurica var. japonica trees in a floodplain forest

We measured methane (CH₄) emissions from the stem surfaces of mature Fraxinus mandshurica var. japonica trees in a floodplain forest. Flux measurements were conducted almost monthly from May to October 2005, and positive CH₄ fluxes were detected throughout the study period, including the leafless season. The mean CH₄ flux was 176 and 97 μg CH₄ m⁻² h⁻¹ at the lower (15 cm above the ground) and upper (70 cm above the ground) stem positions, respectively. The CH₄ concentration was lower in soil gas than in ambient air to a depth of at least 40 cm. One possible source of CH₄ emitted from the stems might be the dissolved CH₄ in groundwater; maximum concentrations were 10,000 times higher than atmospheric CH₄ concentrations. Our results suggest that CH₄ transport from the submerged soil layer to the atmosphere may occur through internal air spaces in tree bodies.     

妊娠猪舍氨气及氧化亚氮浓度测定与排放通量的估算

在北京选择一典型猪场，对不同季节妊娠舍的氨气及氧化亚氮浓度进行了为期1年的试验测定，并根据二氧化碳平衡原理，对猪场不同生长阶段的妊娠猪含氮气体的排放通量进行了估算。结果表明：冬季2004年11月氨气和氧化亚氮的平均浓度分别为11.64±4.36，（1.17±0.2）mg／m³，夏季7月舍内氨气和氧化亚氮的平均浓度分别为3.31±2.67，（0.6±0.02）mg／m³；妊娠猪饲养期间的氨气排放通量为每头（185.2～500.8）mg／h，氧化亚氮为（3.85～35.93）mg／h。     

改善农学管理措施减少太湖稻麦轮作NH3和NO排放

以稻麦轮作为对象,采用密闭室-通气法和静态箱-化学发光法对太湖地区空白（不施氮肥）、当地常规（农民习惯管理方式）和保产增效（与当地常规相比,改善作物种植、水分和养分管理方式）3个处理下的氨（NH3）挥发和一氧化氮（NO）排放进行田间原位观测,研究保产增效措施对稻麦轮作NH3 挥发和NO排放的综合影响。结果表明,与当地常规相比,保产增效在施氮量减少25%的情况下,总作物产量没有降低,且农学利用率提高了39%;保产增效NH3挥发量在稻季和麦季分别减少了26%和44%;保产增效在稻季NO排放量较低（0.75±0.03 kg N/hm2）,与空白和当地常规均没有显著差异（p<0.05）,在麦季NO排放量则显著降低了49%。因此,保产增效措施不仅能保障高产和提高氮利用率,还能减少NH3和NO排放,值得在太湖地区推广。     

The effect of growing soybean (Glycine max. L.) on N2O emission from soil

A pot experiment was conducted to investigate the effect of growing soybean on N₂O emission from soil. When soybean was growing in pots, the cumulative N₂O emission during the growing season was 2.26 mg N pot⁻¹, which was 5.9 times greater than that from the identical but unplanted pots (CK). However, the difference in N₂O fluxes between the two treatments was not significant until the grain-filling stage. Of the total N₂O emission, 94% took place during the period from grain-filling to ripening. Premature harvesting of the aerial parts of the plants at various growth stages substantially stimulated N₂O emission from the soil. These results implied that the process of symbiotic N fixation per se does not stimulate N₂O production or emission, but rather senescence and decomposition of the roots and nodules in the late growth stage. Therefore, additional N₂O would be emitted from the soil after harvesting of soybean with roots, litter, and residues left in situ.