市售三七中五氯硝基苯的残留情况调查

目的：建立三七药材中分析五氯硝基苯（CBPN）残留量的毛细管气相色谱法,考察文山三七药材中的五氯硝基苯残留量情况。方法：样品用正已烷提取,用硅镁吸附剂预处理小柱净化,采用OV-17毛细管柱（30m×0．53mm,1um）及电子捕获检测器（ECD）,外标法计算含量。结果：平均加样回收率为93．6％,部分样品检出的五氯硝基苯残留量超过日本肯定列表限量。结论：建立的方法适用于三七中五氯硝基苯残留量的测定,有必要对三七药材中有机氯农药残留量制定相应的限量标准,并强令禁止销售和使用。     

Quantitative analysis of ruminal methanogenic microbial populations in beef cattle divergent in phenotypic residual feed intake（RFI）offered contrasting diets

Background：Methane（CH_4） emissions in cattle are an undesirable end product of rumen methanogenic fermentative activity as they are associated not only with negative environmental impacts but also with reduced host feed efficiency.The aim of this study was to quantify total and specific rumen microbial methanogenic populations in beef cattle divergently selected for residual feed intake（RFI） while offered（i） a low energy high forage（HF） diet followed by（ii） a high energy low forage（LF） diet.Ruminal fluid was collected from 14 high（H）and 14 low（L） RFI animals across both dietary periods.Quantitative real time PCR（qRT-PCR） analysis was conducted to quantify the abundance of total and specific rumen methanogenic microbes.Spearman correlation analysis was used to investigate the association between the relative abundance of methanogens and animal performance,rumen fermentation variables and diet digestibility.Results：Abundance of methanogens,did not differ between RFI phenotypes.However,relative abundance of total and specific methanogen species was affected（P〈 0.05） by diet type,with greater abundance observed while animals were offered the LF compared to the HF diet.Conclusions：These findings suggest that differences in abundance of specific rumen methanogen species may not contribute to variation in CH_4 emissions between efficient and inefficient animals,however dietary manipulation can influence the abundance of total and specific methanogen species.     

毛豆中丙溴磷残留量的测定及降解动态分析

在反复试验的基础上,建立了毛豆中丙溴磷残留量定量检测的气相色谱法。对分析方法的适合性测定结果表明,方法的回收率为86.5%～95.1%,其RSD为2.68%～6.79%,最小检测量0.00425ng,最小检出浓度为0.002mg/kg,该分析方法简便、准确、能满足实际样品分析。2004年、2005年对丙溴磷在毛豆的残留动态分析结果表明,丙溴磷在毛豆上有较高的原始沉积量,在毛豆上降解规律符合一级动力学方程,根据该方程测算,丙溴磷在毛豆中的半衰期(DT50)为3.2～3.5d,降解99%所需要的时间(T0.99)为21.3～23.5d。     

秸秆腐解过程中土壤热值与有机养分动态

研究玉米秸秆在3种长期试验地(葡萄园、桃园、农田)腐解过程中土壤热值和养分动态变化情况,为秸秆资源的合理利用和土壤培肥提供科学依据。于2011年10月至2012年10月在陕西杨凌进行,采用尼龙网袋法进行玉米秸秆腐解试验,定期取样测定秸秆的腐解残留率,研究紧贴尼龙网袋土壤的热值及其养分变化。结果表明:随着腐解时间的增加,秸秆在0～270d腐解迅速,残留率基本为50%左右,在270～360d腐解速度减慢,最终玉米秸秆在农田、桃园、葡萄园的腐解残留率分别为41.73%、36.11%、46.14%。3个试验地对秸秆腐解过程中土壤热值的影响差异不显著。土壤温度与秸秆腐解的残留率变化呈极显著负相关,影响秸秆在土壤中的腐解速度。整个腐解期间,除了秸秆腐解过程中土壤有机碳的变化不大,农田土壤pH基本不变,果园土壤pH下降了2.06%～2.32%;农田和桃园土壤速效磷分别增加了14.2%和67.5%,而葡萄园土壤速效磷降低了26.9%;农田、桃园和葡萄园的土壤速效钾分别增加了49.9%,43.0%和89.2%。3个试验地土壤易氧化有机碳、稳定性有机碳和碱解氮质量分数之间差异不显著。秸秆腐解在前、中期降解较快,后期趋缓。土壤温度、易氧化有机碳、稳定性有机碳、速效钾影响玉米秸秆在土壤中的腐解速度。果园土壤的有机碳和速效钾质量分数极显著高于农田土壤,说明生草可以提高果园土壤的部分养分质量分数,提高秸秆还田效果,农田土壤在秸秆还田时可调控因素比果园土壤多。可见,植物秸秆在腐解过程中会不同程度影响土壤养分质量分数的变化,提高部分有效养分质量分数,对土壤肥力和质量的提升起到一定的作用。     

Poultry litter and tillage influences on corn production and soil nutrients in a Kentucky silt loam soil

Broiler chicken (Gallus gallus) manure, a rich source of plant nutrients, is generated in large quantities in southeastern USA where many row crops, such as corn (Zea mays L.), are also extensively grown. However, the use of broiler manure as an economical alternative source of nutrients for corn production has not been extensively explored in this region. This study was conducted to examine the use of broiler litter as a source of nutrients for corn production, as influenced by tillage and litter rate, and any residual effects following application. In addition, the consequence of litter application to soil test nutrient levels, particularly P, Zn and Cu, was explored. The treatments consisted of two rates of broiler litter application, 11 and 22 Mg ha⁻¹ on a wet weight basis, and one rate of chemical fertilizer applied under no-till and conventional tillage systems. Treatments were replicated three times in a randomized complete block design. Corn was grown with broiler litter and inorganic fertilizer applied to the same plots each year from 1998 to 2001. In 2002 and 2003, corn was planted no-till, but only N fertilizer was applied in order to make use of other residual litter nutrients. Soil samples were taken yearly in the spring prior to litter application and 4 years after the cessation of litter application to evaluate the status of the residual nutrients in soil. Two years out of the 4-year experiment, broiler litter application produced significantly greater corn grain yield than equivalent chemical fertilizer application and produced similar grain yield in the other 2 years. Corn grain yield was significantly greater under no-till in 1999, but significantly greater under conventional-till in 2000, and no difference between the two tillage systems were observed in 1998 and 2001. With 4 years of litter application, Mehlich-3 P increased from an initial 18 mg kg⁻¹ to 156 mg kg⁻¹ with 11 Mg ha⁻¹ litter and to 257 mg kg⁻¹ with 22 Mg ha⁻¹ litter. For every 6 kg ha⁻¹ of P applied in poultry litter Mehlich-3 P was increased by 1 mg kg⁻¹. Modest increases in Mehlich-3 Cu and Zn did not result in phytotoxic levels. This study indicated that an optimum rate of broiler litter as a primary fertilizer at 11 Mg ha⁻¹ applied in 4 consecutive years on a silt loam soil produced corn grain yields similar to chemical fertilizer under both no-till and conventional tillage systems and kept soil test P, Cu and Zn levels below values considered to be harmful to surface water quality or the crop.     

返滴定法测定白矾散中白矾的含量

建立了白矾散中白矾含量测定的方法。样品在600℃灰化2 h,稀盐酸溶解,过量EDTA-2Na配位AL~(3+),以二甲酚橙作为指示剂,锌滴定液滴定剩余的EDTA-2Na,计算白矾的含量。经方法学考察,本方法符合含量测定要求,平均回收率为97.6%,RSD为0.8%。所建立的测定方法结果稳定可靠、重现性好,可用于白矾散的质量控制。     

稻-稻-油种植制硫肥效应及硫素平衡研究

研究了稻-稻-油种植制硫肥效应及土壤硫素平衡,结果表明:不同硫肥品种在水稻上的增产效应以硫酸钾最好,硫磺次之;在油菜上以石膏最好,硫磺次之。硫素当季利用率早稻为7 5%,晚稻为10.9%,油菜为29 6%。在不施硫条件下,土壤硫素表现亏缺;在施低量硫条件下(每季作物施硫15kg/hm2)基本上可以保持土壤硫素的平衡;在施中、高量硫条件下,土壤硫素均有不同程度盈余。施用硫肥具有明显的后效,连续两年施用硫肥后,可以隔年或隔季不施。     

孔雀石绿等染料物质残留检测过程中实验室污染的来源分析

为了分析孔雀石绿等残留检测过程中实验室污染的来源,本研究应用超高效液相-串联质谱法(UPLC-MS/MS)测定了常用实验室用品中孔雀石绿、无色孔雀石绿、结晶紫、无色结晶紫、亚甲基蓝的含量.纸样品用乙腈直接提取;笔样品采用书写痕迹后再用乙腈提取,UPLC-MS/MS定量测定.结果表明:在纸样品中,除了实验滤纸外,其它纸样品(如A4打印纸、报纸、标签纸等)均含有一定水平的目标物;笔样品中,除了铅笔2H、中性笔135012蓝、中性笔2180蓝色外,其它笔样品(如圆珠笔、记号笔、签字笔、水笔等)含有一定水平的目标物.为了降低实验室目标物污染风险,本文还对样品处理前和处理中的各个环节需要注意的问题做了较为详细的分析.本研究结果将有利于建立有效预防体系从而尽量避免样品在该类物质残留检测中的实验室本底污染和假阳性结果.     

金属板料受控激光喷丸强化的残余应力场分析

在分析受控激光喷丸强化机理的基础上,通过激光喷丸强化力学效应的物理模型和残余应力的弹塑性模型,分析了激光喷丸强化诱导残余应力的特点,研究了残余应力大小和深度与激光喷丸工艺参数的关系。通过调整激光参数及工艺条件以控制残余应力场的分布,并根据残余应力场的分布判断激光喷丸强化效果,保证了受控激光喷丸强化后工件的疲劳寿命获得较大幅度的提高。