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71.
Siwei Shi Qingzhong Zhang Yilai Lou Zhangliu Du Qian Wang Ning Hu Yidong Wang Anna Gunina Jiqing Song 《Soil Use and Management》2021,37(1):95-103
Biochar addition can expand soil organic carbon (SOC) stock and has potential ability in mitigating climate change. Also, some incubation experiments have shown that biochar can increase soil inorganic carbon (SIC) contents. However, there is no direct evidence for this from the field experiment. In order to make up the sparseness of available data resulting from the long‐term effect of biochar amendment on soil carbon fractions, here we detected the contents and stocks of the bulk SIC and SOC fractions based on a 10‐year field experiment of consecutive biochar application in Shandong Province, China. There are three biochar treatments as no‐biochar (control), and biochar application at 4.5 Mg ha?1 year?1 (B4.5) and 9.0 Mg ha?1 year?1 (B9.0), respectively. The results showed that biochar application significantly enhanced SIC content (3.2%–24.3%), >53 μm particulate organic carbon content (POC, 38.2%–166.2%) and total soil organic carbon content (15.8%–82.2%), compared with the no‐biochar control. However, <53 μm silt–clay‐associated organic carbon (SCOC) content was significantly decreased (14%–27%) under the B9.0 treatment. Our study provides the direct field evidence that SIC contributed to carbon sequestration after the biochar application, and indicates that the applied biochar was allocated mainly in POC fraction. Further, the decreased SCOC and increased microbial biomass carbon contents observed in field suggest that the biochar application might exert a positive priming effect on native soil organic carbon. 相似文献
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73.
Surveys were conducted in the five southern rice-producing states of Arkansas, Louisiana, Mississippi, Missouri and Texas in the United States during the 2018 and 2019 cropping seasons to determine the distribution and pathogenicity of fungal pathogens associated with seedling blight in rice. A total of 349 pathogenic fungal isolates were collected and identified as belonging to four genera: Rhizoctonia solani, Fusarium spp., Sclerotium rolfsii and Marasmius graminum based on morphological characteristics, molecular analysis and Koch's postulates. R. solani (252 out of 349 pathogenic isolates) was the most prevalent fungus isolated from diseased samples. Of the 252 pathogenic R. solani isolates, 245 were further classified as anastomosis group 11 (AG-11) and 7 as AG-4. Isolates of R. solani AG-4 and M. graminum were the most aggressive, with the highest stand loss (63% to 100%) and median disease rating (DR; 5.0), followed by isolates of R. solani AG-11 (stand loss = 4% to 100% and DR = 0.6 to 5.0), Fusarium spp. (stand loss = 26% to 48% and DR = 2.0 to 5.0) and S. rolfsii (stand loss = 33% to 48% and DR = 2.0 to 3.0) in causing seedling blight in rice. R. solani (62% to 83% of total pathogenic isolates) and Fusarium spp. (10% to 24% of total pathogenic isolates) were predominant in all the five states surveyed. S. rolfsii and M. graminum were present only in Louisiana and Texas. The results of this first systematic survey of rice seedling diseases in the southern United States will help develop effective fungicide seed treatment strategies for control of stand loss caused by seedling blight, one of the major factors limiting rice production. 相似文献
74.
为探究梨火疫病菌解淀粉欧文氏菌Erwinia amylovora在全球的潜在地理分布,基于其全球分布数据和筛选得到的环境变量,利用MaxEnt模型对其在当前气候和未来气候条件下的潜在地理分布进行预测,并利用刀切法和皮尔逊相关性分析法筛选对梨火疫病菌分布有重要影响的环境变量。结果显示,对梨火疫病菌分布有重要影响的环境变量包括2月平均最高温度、1月平均降水量、7月平均最低温度、温度变化方差、昼夜温差月均值和7月平均降水量,表明春季和夏季的温度和降水对梨火疫病菌的分布有较大影响。在当前气候条件下,梨火疫病菌在全球的适生区分布较广,适生区总面积达到5.58×107 km2,且高适生区主要分布在北美洲沿海地区、地中海沿岸和亚洲中部及东部的部分地区;梨火疫病菌在我国的适生区总面积为7.36×106 km2,占全国陆地总面积的76.70%;在未来气候SSP126和SSP585情景下,梨火疫病菌在全球的适生区总面积分别为5.52×107 km2和5.24×107 km2。表明梨火疫病菌对我国大部分地区有潜在威胁,应加强监测与防控。 相似文献
75.
76.
针对J亚群禽白血病病毒(ALV-J)基因序列保守区域设计一对特异性引物和一条特异性探针,通过构建重组阳性标准质粒作为阳性标准品,建立了检测ALV-J核酸的荧光定量PCR方法。优化反应体系和条件后进行特异性、敏感性、重复性试验。结果显示,该检测方法特异性强,与其它禽源病毒如A亚群禽白血病病毒(ALV-A)、B亚群禽白血病病毒(ALV-B)、新城疫病毒( NDV)、禽流感病毒(AIV)、鸡传染性贫血病毒(CIAV)和马立克病病毒(MDV)均不发生交叉反应;该方法可检测到3.2×102拷贝/μL的病毒核酸,与常规RT-PCR相比,敏感性高100倍;重复性试验的变异系数小于2%。研究结果表明,建立的Real-time RT-PCR 检测方法特异性强、灵敏度高、可重复性好,可用于ALV-J的定量检测。 相似文献
77.
为了快速检测鱼类神经坏死病毒,本研究设计了病毒特异性的发夹型探针,经硫醇修饰后与纳米银溶胶结合,制备了鱼类神经坏死病毒纳米探针(Ag-NNV),并使用透射电镜、多功能酶标仪、表面增强拉曼光谱仪等对纳米探针Ag-NNV的表征及发夹型探针在纳米银粒子表面的覆盖率进行了测定和分析。结果表明,裸露的纳米银粒子为球形,平均直径50 nm;制备的纳米探针颗粒为球形,平均直径90 nm。纳米银粒子和纳米探针在溶液中均具有良好的分散性。平均每个纳米银粒子表面结合发夹型探针约100条,单位表面积的探针覆盖量为0.56 pmol/cm2。该纳米探针制备简便,适合用于表面增强拉曼散射法对鱼类神经坏死病毒进行快速检测。 相似文献
78.
为给水貂阿留申病疫苗的研制奠定基础,对疑似感染阿留申病死亡的水貂内脏处理后,接种猫肾传代细胞(CRFK)分离病毒,并对分离的毒株进行PCR鉴定及动物回归试验。与此同时,首次应用免疫过氧化物酶单层细胞实验(IPMA)对所分离的水貂阿留申病毒进行TCID50的测定。结果成功分离并鉴定出5株水貂阿留申病毒株,分别命名为ADV-DL124、ADV-DL125、ADV-ZJ3、ADV-QD2、ADV-QD3,各分离株的TCID50分别为105.7TCID50/ml、105.0TCID50/ml、104.6 TCID50/mL、105.2 TCID50/mL、104.1 TCID50/mL。动物回归实验显示,所分离的病毒对水貂具有致病性,为水貂阿留申病毒强毒株。 相似文献
79.
80.
The Effect of Season on Spermatozoa Motility,Plasma Membrane and Acrosome Integrity in Fresh and Frozen–Thawed Semen from Xinong Saanen Bucks 下载免费PDF全文
W Wang J Luo S Sun L Xi Q Gao AB Haile H Shi W Zhang H Shi 《Reproduction in domestic animals》2015,50(1):23-28
The aim of this study was to evaluate whether the season of ejaculate collection influences seminal quality parameters of pre‐ and post‐freeze–thawing in Xinong Saanen bucks. Ejaculates were collected from eight bucks throughout the four seasons (spring, summer, autumn and winter) in a 12 months’ time period, identified in the Northern Hemisphere. Semen samples were evaluated by the combinations of conventional and Computer‐Assisted Sperm Analysis (CASA) when fresh and after frozen–thawed, respectively. The results clearly demonstrated that season of ejaculate collection influenced (p < 0.05) fresh semen quality. Highest semen quality was observed during autumn. On the contrary, undesirable indices (significantly lower, p < 0.05) were observed in winter as compared with the other remaining seasons. CASA has clearly shown the influences of seasonal variations on semen motility parameters. Furthermore, season of ejaculate collection was also found to influence sperm freezability. Semen characteristics after frozen–thawed followed a similar pattern with that of fresh ejaculate except in spring. The results revealed that sperm quality was higher (p < 0.01) in summer and autumn than in spring and winter. In conclusion, seasonal variation influences semen quality in Xinong Saanen bucks. In addition to summer and autumn, fresh ejaculates in spring can also be successfully used for AI. Sperm from ejaculates collected during summer and autumn are more suitable for cryopreservation. Hence, it is possible to increase the efficiency of goat breeding by manipulating the seasonal variations of semen quality for immediate AI and/or cryopreservation. 相似文献