Concurrent 2009 Pandemic Influenza A (H1N1) Virus Infection in Ferrets and in a Community in Pennsylvania

We report a fall 2010 cluster of pandemic influenza A/H1N1 (pH1N1) infections in pet ferrets in Lehigh Valley region of Pennsylvania. The ferrets were associated with one pet shop. The influenza cluster occurred during a period when the existing human surveillance systems had identified little to no pH1N1 in humans in the Lehigh Valley, and there were no routine influenza surveillance systems for exotic pets. The index case was a 2.5‐month‐old neutered male ferret that was presented to a veterinary clinic with severe influenza‐like illness (ILI). In response to laboratory notification of a positive influenza test result, and upon request from the Pennsylvania Department of Health (PADOH), the Pennsylvania Department of Agriculture (PDA) conducted an investigation to identify other ill ferrets and to identify the source and extent of infection. PDA notified the PADOH of the pH1N1 infection in the ferrets, leading to enhanced human surveillance and the detection of pH1N1 human infections in the surrounding community. Five additional ferrets with ILI linked to the pet shop were identified. This simultaneous outbreak of ferret and human pH1N1 demonstrates the important link between animal health and public health and highlights the potential use of veterinary clinics for sentinel surveillance of diseases shared between animals and humans.     

不同碳氮磷源改良剂对铅锌尾矿废弃地土壤微生物群落结构的影响

为分析土壤微生物群落结构对退化生态系统恢复过程的价值,开展野外田间实验,添加不同碳氮磷源改良剂对铅锌尾矿废弃地进行生态恢复,研究其对土壤微生物群落结构的影响。结果表明:与对照相比,添加碳氮磷源改良剂显著提高了土壤微生物OTU数,微生物多样性指数(Chao1、ACE、Simpson、Shannon),微生物活性和微生物生物量。与对照相比,添加碳氮磷源改良剂显著改变了土壤微生物群落组成,相对丰度增加的微生物门有Bacteroidetes、Euryarchaeota、Verrucomicrobia、Acidobacteria和Candidate_division_OD1,相对丰度增加的微生物属有Solitalea、Sphingomonas、Blastocatella、Planctomyces、Opitutus、Ohtaekwangia和Gemmata;相对丰度降低的微生物门是Cyanobacteria,相对丰度降低的微生物属是Gaiella。Pearson相关性分析表明:在门水平上,Bacteroidetes、Planctomycetes、Euryarchaeota、Verrucomicrobia与微生物活性、微生物生物量呈显著正相关,Chloroflexi、Cyanobacteria与微生物活性、微生物生物量呈显著负相关;在属水平上,Solitalea、Opitutus、Blastocatella、Ohtaekwangia与微生物活性、微生物生物量呈显著正相关;Gaiella与微生物活性、微生物生物量呈极显著负相关。聚合促进树分析表明:在门水平上,尾矿(CK)、尾矿+尿素(N)、尾矿+中药渣+尿素(MHR+N)处理聚在一起,尾矿+磷肥(P)、尾矿+中药渣(MHR)、尾矿+中药渣+磷肥(MHR+P)和尾矿+中药渣+尿素+磷肥(MHR+N+P)处理聚在一起;在属水平上,CK单列,N、P、MHR、MHR+N、MHR+P和MHR+N+P处理聚在一起。综合分析表明,添加不同碳氮磷源改良剂对土壤微生物群落组成、多样性、微生物活性和微生物生物量均有显著性影响,其中MHR+P和MHR+N+P处理效果最好。     

外源喷施FeSO4对‘黄金梨’黄化叶片氮代谢相关酶活性及基因表达量的影响

为了探寻供铁水平对梨叶片氮代谢相关酶活性及基因表达量的影响,利用不同浓度FeSO₄喷施‘黄金梨’,分析处理3、6、9 和12 d后‘黄金梨’叶片中N含量,硝酸还原酶（NR）、亚硝酸还原酶（NiR）、谷氨酰胺合成酶（GS）和谷氨酸合酶（GOGAT）的酶活性及其基因表达量差异。结果表明,通过不同浓度FeSO₄处理,‘黄金梨’叶片中N含量均显著性增加,达到正常叶片中含量水平。黄化‘黄金梨’叶片中4种酶活性显著低于正常叶片,供铁显著增强了黄化‘黄金梨’叶片中NR、NiR、GS和GOGAT酶活性。黄化‘黄金梨’叶片4种酶基因表达量显著低于正常叶片;随着喷施水平的提高,NR、Fd-GOGAT和GS基因表达量较黄化叶片有显著性上升;0.10%和0.15%的FeSO₄处理的NiR基因表达量显著高于未处理黄化叶片。该结果说明叶片施Fe增强相关酶活性,提高相关基因表达水平,有效的促进N含量的增加;叶面喷施外源FeSO₄可有效恢复黄金梨叶片黄化的症状,以0.10%~0.15%浓度处理效果最好。     

秸秆热解多联产模式环境影响评价

为定量评价秸秆热解多联产工程的环境影响,借鉴生命周期评价方法,将秸秆热解多联产系统工程建设单元的物质和能量投入及其环境排放纳入系统边界,对年秸秆处理能力1.0×10~4 t的秸秆热解多联产系统的环境影响进行分析评价。结果表明,不考虑产出品的替代减排,该系统生命周期的环境影响综合指数为175.53。其中,工程建设单元、运行单元和产物利用单元的环境影响潜值分别占18.10%、78.75%和3.15%。钢材和PVC管等物料的环境排放合计占建设单元环境排放综合潜值的93.49%,电力消耗排放占运行单元环境排放综合潜值的93.86%。从资源替代角度看,秸秆燃气替代煤炭、秸秆炭和木醋液分别减施化肥和农药情景下,该项目功能单位的环境影响综合指数为-496.86。秸秆热解多联产系统通过资源替代可有效减少环境排放,具有良好的环境减排效应。在未来秸秆热解多联产系统建设过程中,应选择低碳环保的建筑材料,降低运行电耗。     

Closing the nitrogen use efficiency gap and reducing the environmental impact of wheat-maize cropping on smallholder farms in the Guanzhong Plain,Northwest China

A high crop yield with the minimum possible cost to the environment is generally desirable. However, the complicated relationships among crop production, nitrogen (N) use efficiency and environmental impacts must be clearly assessed. We conducted a series of on-farm N application rate experiments to establish the linkage between crop yield and N₂O emissions in the Guanzhong Plain in Northwest China. We also examined crop yield, partial factor productivity of applied N (PFPN) and reactive N (Nr) losses through a survey of 1 529 and 1 497 smallholder farms that grow wheat and maize, respectively, in the region. The optimum N rates were 175 and 214 kg ha^–1 for winter wheat and summer maize, respectively, thereby achieving the yields of 6 799 and 7 518 kg ha^–1, correspondingly, with low N₂O emissions based on on-farm N rate experiments. Among the smallholder farms, the average N application rates were 215 and 294 kg ha^–1 season^–1, thus producing 6 490 and 6 220 kg ha^–1 of wheat and maize, respectively. The corresponding PFPN values for the two crops were 36.8 and 21.2 kg N kg^–1, and the total N₂O emissions were 1.50 and 3.88 kg ha^–1, respectively. High N balance, large Nr losses and elevated N₂O emissions could be explained by the overdoses of N application and low grain yields under the current farming practice. The crop yields, N application rates, PFPN and total N₂O for wheat and maize were 18 and 24% higher, 42 and 37% less, 75 and 116% higher, and 42 and 47% less, correspondingly, in the high-yield and high-PFPN group than in the average smallholder farms. In conclusion, closing the PFPN gap between the current average and the value for the high-yield and high-PFPN group would increase crop production and reduce Nr losses or the total N₂O emissions for the investigated cropping system in Northwest China.     

土壤肥力质量与施氮量对小麦氮肥利用效率的综合定量关系研究

耕地土壤肥力及施氮量对于小麦产量和氮肥利用率均具有重要影响,但它们综合影响的定量关系及相对贡献率并不清楚。在太湖流域常熟市研究区,通过设置不同土壤肥力与施氮量的小麦田间试验,研究施氮量、土壤肥力综合质量指数对小麦产量和氮肥利用率的影响,并利用多元回归方法拟合他们之间的定量关系方程,分析揭示施氮量与土壤肥力综合质量指数对小麦产量和氮肥利用率综合影响的相对贡献率。结果表明,提升施氮量和土壤肥力综合质量指数,有利于增加小麦产量,但不利于小麦氮肥利用率提升;土壤肥力综合质量指数对小麦产量和氮肥利用率的影响大于施氮量,两者对产量和氮肥利用率的相对贡献率比值分别为1.09∶1和1.32∶1。表明通过提升土壤综合肥力、削减氮肥施用量,达到粮食与生态双重安全目标,培育和提升耕地土壤质量显得更为基本和重要。     

沙地土壤C∶N∶P比对早期植物群落物种多样性的影响

为揭示土壤碳∶氮∶磷(C∶N∶P)比对植物群落物种多样性的影响,以宁夏哈巴湖国家级自然保护区内沙地植物群落(沙柳群落和油蒿群落)为研究对象,调查计算了沙地植物群落的物种多样性,测定了群落中土壤C、N、P含量,分析讨论了土壤C∶N∶P比与沙地植物群落物种多样性之间的关系。结果表明,分布于流动、半固定沙地的沙柳群落其土壤C∶N∶P比对物种多样性的影响不显著,而分布于半固定、固定沙地的油蒿群落其土壤C∶N∶P比对物种多样性的影响显著。这说明沙地植物群落生物量不断增大的同时,枯枝落叶增多,土壤C、N、P显著增多,较大的土壤C∶N比与N∶P比与不断增大的物种多样性有趋同变化,因此,土壤的C∶N∶P比能够影响沙地植物群落的物种多样性。     

长江三角洲农田地下水反硝化对硝酸盐的去除作用

长江三角洲(简称"长三角")农田氮素投入量高,但是否像其他高氮投入农田一样在土壤剖面累积了大量硝酸盐尚不清楚。通过连续两年的野外观测结合室内培养实验,发现长三角地区3种不同类型的高氮投入农田1～4 m地下水硝态氮(NO_3~--N)剖面分布特征存在明显差异,水稻田地下水NO_3~--N浓度始终很低(1mg·L~(-1)),不同深度之间无差异。蔬菜地和葡萄园1 m处地下水NO_3~--N年平均浓度分别为5.6和17.5 mg·L~(-1),但是地下水NO_3~--N浓度随着深度增加急剧下降,至4m处,NO_3~--N浓度降至小于1 mg·L~(-1),与水稻田无差异。蔬菜地和葡萄园地下水高浓度NO_3~--N仅出现在施肥期间,非施肥期地下水NO_3~--N浓度较低,这表明长三角农田不存在明显的NO_3~--N累积。原状土柱培养实验结果表明,0～4 m土壤均存在较强的反硝化活性。通过对地下水中反硝化产物N2及N2O的直接定量测定,发现反硝化对地下水NO_3~--N的去除效率随着深度而增加,至4m处,反硝化对地下水NO_3~--N的去除效率分别为86%(水稻田)、93%(蔬菜地)和89%(葡萄园)。这表明反硝化能有效去除地下水NO_3~--N,是长三角地区农田土壤剖面未产生NO_3~--N累积的重要原因。反硝化产生的溶解性气态氮主要通过地下水流入临近水域,对于蔬菜地和葡萄园而言,溶解性气态氮流失量与NO_3~--N淋溶损失量相当,是一个重要的氮素去向,值得关注。     

Optimal Management Practices for Nitrogen Application in Corn Cultivated During Summer and Fall in the Tropics

Optimal management practices for nitrogen (N) fertilization is well defined for corn (Zea mays) cultivated during summer (“summer” corn), but not for corn cultivated during the fall (“fall” corn) in the tropics. Two experiments were carried out to evaluate N rates (50, 100, 200, and 300 kg N ha^?1), N application timing (pre-planting – PP, V2–V3, and V5–V6) and N split application, once (at PP, V3, and V6), two (at V3+ V6) and three times (at PP+ V3+ V6) in corn cultivated during summer (2014/2015) and fall (2015/2016). Data on corn grain yield (CGY), weight of 1000-grains, leaf N content and values of soil-plant analyses development (SPAD) were collected and analyzed using univariate, multivariate (principal component analysis, PCA) and regression analysis. Results showed that corn growth was affected by N rates and splitting. Corn cultivated during summer presented higher CGY and weight-1000 g than corn cultivated during the fall. The highest yields were obtained with higher N rates on “summer” corn (125 kg N ha^?1) than “fall” corn (50 kg N ha^?1). Split N-application at vegetative growth stages, V3+ V6, or PP+ V2+ V6, provided higher yields for “summer” corn, while only PP application was a reliable period of N fertilization for “fall” corn. The finding is that corn cultivated during the fall presented a lower response to N and no obvious advantages to split N fertilization when compared to corn cultivated during summer. These optimal management practices for N fertilization in corn production in the tropics depend on soil water availability.