土壤有机质测定方法的分析和探讨

为提高土壤有机质含量检测的工作效率，按照标准方法《土壤检测第6部分：土壤有机质的测定》（NY/T1121.6-2006）中实验步骤增加一种电热消解仪法。将数显恒温油浴锅加热法和电热消解仪加热法的加热方式进行比对。在微沸后计时5min后的两组不同编号的土壤标准物质样品有机质含量结果，不但在标准认定值范围之内，且结果平均值的绝对差值都是0.2g/kg，小于规定的允许绝对差值。实验表明电热消解仪加热法测定出的土壤有机质含量与油浴加热法测出的有机质含量并无显著差异。而电热消解仪加热方式能适应大批量土壤样品，节约时间，更好地提高农业土壤检测水平，进一步促进农业发展。     

王水水浴消解-双道原子荧光光谱法（AFS）同时测定土壤中的汞和硒

建立王水水浴消解一双道原子荧光光谱法同时测定土壤中的汞和硒的方法,优化王水水浴消解和AFS测定条件。该法的汞检出限为0．002μg／L,硒的检出限为O．100wgL;汞的相对标准偏差为0．0020％～0．0340％,硒的相对标准偏差为0．0018％～0．0580％;汞的加标回收率为95．6％-101-4％,硒的加标回收率为96.4％～103．0％。该法操作快速、简便,结果准确、可靠,适用于大批量土壤样品中汞和硒的同时测定。     

CCT-ICP-MS测定土壤中微量元素银

将土壤样品经三酸(硝酸、氢氟酸和硫酸)分解和王水提取后,采用碰撞池技术(CCT)电感耦合等离子体质谱(ICP-MS)法对其中微量元素银进行分析。试验结果表明,元素校正曲线相关系数在0.9995以上;元素方法检出限为0.009μg/g;分析标准物质验证方法精密度和准确度符合标准值;加标回收率在98.0%～108.0%。该方法简单快速、灵敏度高,测定结果较为理想。     

ICP-AES测定磷矿石中多种元素的3种前处理方法比较

以王水分解、四酸分解和偏硼酸锂熔融这3种前处理方法,分别对国家标准物质GBW 07210、GBW 07211、GBW 07212中磷、钙、镁、铁、铝、钾、钠、硅8种元素进行测定,研究不同前处理方法对分析测定结果的影响.     

不同消解方法测定农产品中硒元素的研究

采用微波消解法和水浴消解法分别溶解农产品样品,采用冷原子荧光光谱法测定硒元素的含量。经比较,两种方法的检出限分别为1.05ng/g和0.93ng/g,精密度分别为1.98%~8.44%和1.19%~5.22%。经国家一级标准物质验证,两种消解方法均能满足农产品质量管理规范要求,可用于农产品样品的分析测定。     

岩石矿物及土壤中微量硫测定

建立一种岩石矿物及土壤中微量硫测定的方法。方法检出限为2.835×10-6;对8种国家一级标准物质中硫含量进行测定来检验方法准确度及精密度,测定结果与标准值相符,相对标准偏差小于3%;加标回收率为93.9%~109.0%。该方法可用于岩石矿物及土壤中微量硫的快速、准确检测分析。     

粉煤灰和蚯蚓粪施用对土壤蒸发的影响

为揭示粉煤灰和蚯蚓粪两种土壤改良物质对土壤蒸发影响的差异性,探寻适宜的施用方式和施用量.设计模拟试验,控制3个覆盖处理(覆盖厚度分别为1、2.5和4 cm)和4个混施处理(施用量分别为10％、20％、30％和40％),以温室土壤为对照.连续测定16 d土壤蒸发量,结合有机质含量、水分物理性质和物质本身特性分析粉煤灰和蚯蚓粪施用对土壤蒸发的影响是否有差异及产生差异的原因.结果表明:与对照相比,覆盖粉煤灰和蚯蚓粪累积蒸发量分别减小了30％～34％和17％～48％,混施粉煤灰和蚯蚓粪累积蒸发分别减小了0％～6％和4％～14％.覆盖厚度为1 cm粉煤灰对土壤蒸发的抑制效果优于蚯蚓粪,覆盖厚度为4 cm和混施对土壤蒸发的抑制效果均为蚯蚓粪优于粉煤灰.两种物质覆盖和混施均可提高有机质含量,是其抑制土壤蒸发的主要原因.两种物质抑制蒸发效果具有差异,为有机质含量、颜色和颗粒组成等不同导致.另外,两种物质覆盖、蚯蚓粪混施土壤含水量均高于对照,混施蚯蚓粪显著提高孔隙度和持水容量.综合考虑施用粉煤灰和蚯蚓粪抑制土壤蒸发和保持土壤水分的效果可知,薄层覆盖时,粉煤灰优于蚯蚓粪,中厚层覆盖和混施蚯蚓粪优于粉煤灰.     

重金属混标在土壤检测中的验证——以汞、砷为例

文章采用汞、砷两种重金属标准溶液配制成混标溶液,称取经风干、研磨并经过0.149mm孔径筛的建阳土壤0.5g进行加标,经湿法消解等预处理后,对消解后的土壤中这两种重金属含量进行检测。结果表明,该方法并没干扰汞、砷两种元素标曲的建立,检测结果重现性好,结果准确。     

密封溶样—质谱法测定银

采用密封溶样—质谱法(ICP-MS)测定岩石、矿物、水系沉积物、土壤中的银。该方法检出限为0.02×10-6;通过对7种国家一级标准物质中的银进行测定,检验该方法的准确度及精密度,测定结果与标准值相符,相对标准偏差小于5.00%。该方法简单、快速、灵敏度高,较好地满足了分析要求。     

土壤DOM研究进展

土壤DOM是未遭受侵蚀的生态系统下N和P输出的主要形式,掌握溶解性有机物质中DON的动态变化,对了解土壤肥力,土壤N素的植物有效性以及土壤N素转化、循环过程等具有重要的意义.介绍DOM的主要来源,分析DOM的组成和结构研究方法,探讨DOM含量动态变化的影响因素.     

化探样品中微量元素Ag、W、Mo、Sn、Bi、Cu、Pb、Zn、Ni、Co、Cr的水平撒料光谱定量分析

针对化探样品批量大,元素多,检出限低等特点,采用水平电极撒料法,对化探样中多种微量元素进行了光谱定量分析.将样品与缓冲剂1:1混匀,采用W-100光栅摄谱仪(光栅刻线1200条/毫米,二级光谱)进行水平撒样摄谱,谱板经暗室处理后,在东德GFE760μ测微光度计上用P标尺测光,以△P-logc绘制工作曲线,查出含量.本法采用了特制的撒样漏斗,改善了下料的均匀性,提高了分析精度;以Ge和Pd作内标消除工作条件变化对谱线强度的影响;同时还试选了SiO2:C:Na2SO4＝61:30:9的混合物作缓冲剂,提高了弧烧的稳定性,获得了较高的再现性.本文还采用了一种单元素线减光器对Ag3382.9进行减光,使Ag的测定上限由5×10-6提高到30×10-6.本法操作简便快速,成本较低,一次可测定Ag、W、Mo、Sn、Bi、Cu、Pb、Zn、Ni、Co、Cr等多种元素,检出限为Ag 0.03×10-6,W 0.5×10-6,Mo0.05×10-6,Sn 0.4×10-6,Pb 1×10-6,Zn 3×10-6,Cu 0.5×10-6,Bi 0.1×10-6,Ni 0.3×10-6,Co 0.3×10-6,Cr 1×10-6,基本上达到了化探普查找矿定量分析的要求.     

2010年世界健康食品展望

当前,中国粮油企业的生存与发展已与世界粮油经济的发展息息相关。无论是粮油企业全面亏损的2004年,还是粮油价格大起大落的2008年,世界其他各国粮油政策和价格的变化均对中国的粮油产业发展造成了很大的影响。全面了解国际粮油发展新动向、掌握世界粮油食品发展新方向,从宏观上为企业找到准确定位,是每位粮油企业家、每位粮油人都必须具备的。正所谓知己知彼,百战不殆,希望以下这些国际前沿信息能为您带来收获。     

冀、鲁、豫、苏、皖五省农机夏收跨区作业调研报告

农机跨区作业是我国农民自发进行的又一项伟大的制度创新,为促进我国农业机械化发展做出了重要的贡献.为此,采用问卷调查法、文献资料法和数理统计法,对冀、鲁、豫、苏、皖等省505户参与跨区作业的农机大户进行了问卷调查.以问卷数据为基础,分析了农机大户的自身特征和经营状况,并总结了影响跨农机大户参与跨区作业的主要因素,最后提出了相应的对策建议.     

安徽省砀山县丰产农机合作社:创新模式发展优势服务

砀山县丰产农机服务专业合作社位于安徽省宿州市砀山县朱楼镇朱楼村,成立于2015年5月13日。合作社目前占地1.33 hm^2(20余亩),拥有成员200余人,拖拉机40多台,收割机18台,灌溉机械14套,植保飞机80多架,烘干机6组,配套农具230多台(套),机械资产达到1 200余万元。     

Advection,evaporation, and surface resistance

Summary We study the effect of surface resistance r (whether of monolayers on free water or plant diffusive resistance) on evaporation rate, energy balance, and microclimate, under advective conditions. We use power-law representations of the vertical profiles of mean windspeed and eddy diffusivity, and exploit two known similarity solutions, one for a step-function change of surface concentration, and the other for a step-function change of surface flux density. To a very close approximation, these two contrasting canonical advective problems yield the same (spatially variable) boundary layer transfer coefficient expressing the ratio of the surface flux perturbation to the surface concentration perturbation. Adopting this coefficient reduces the (spatially variable) surface energy balance for the advective boundary layer with surface resistance to a quadratic equation, with the solution yielding the fetch distances x at which the surface temperature assumes a given value To. With To (x) established thus, the other significant properties of the boundary layer follow simply and directly.The results reveal the profound influence of r, especially at small x. As boundary layer atmospheric resistance increases with x, r becomes relatively less important. It can be regarded as primarily reducing advective effects. Antievaporation films thus work best on small water surfaces in arid surroundings, but are less effective the larger the water body and the moister the surrounds. If leaf temperatures are not limiting, increasing r has greatest effect for small vegetated areas in an arid environment, but may not be optimal for extensive continuous monocultures. Control of surface resistance offers means of manipulating microclimate, for example when arid landscapes are watered for this purpose. The exploratory nature of this investigation, and its many limitations, are stressed.     

一株中温厌氧纤维素降解细菌的分离、鉴定及其系统发育分析

以树中心湿木为样品,富集分离获得一株具有较强纤维素分解能力的中温厌氧纤维素降解细菌CSZM-6.分离菌株革兰氏染色阴性,直杆或稍弯曲杆状,多数单生,少数成对或成串,部分菌体产芽孢.菌体大小为0.5μm×1.7～2.6μm,严格厌氧,最适生长温度40℃,最适pH6.5,以葡萄糖为底物时倍增时间8.0h.分离菌株在纤维素粉固体培养基中培养3周后,菌落为圆形或不规则形状,产黄色素,直径为0.5～4.0mm,水解圈直径为2.0～18.0mm.分离菌株不仅能利用纤维素、纤维二糖、葡萄糖等碳水化合物,还能利用未经处理的报纸、水稻秸秆、麦秆.发酵纤维素产乙醇、乙酸、H2、CO2、甲酸、丙酸、乳酸.在菌株CSZM-6的纤维素酶系中,只存在外切-β-1,4-葡聚糖酶(C1酶)和内切-β-1,4-葡聚糖酶(Cx酶)两种组分,最适温度分别为40℃和45℃.通过16SrDNA序列分析表明,菌株CSZM-6为梭菌属Clostridium,与C. papyrosolvens具有99.6%的相似性.     

The FARMSCAPE approach to decision support: farmers', advisers', researchers' monitoring,simulation, communication and performance evaluation

FARMSCAPE (Farmers', Advisers', Researchers', Monitoring, Simulation, Communication And Performance Evaluation) is a program of participatory research with the farming community of northeast Australia. It initially involved research to explore whether farmers and their advisers could gain benefit from tools such as soil characterisation and sampling, climate forecasts and, in particular, simulation modelling. Its current focus is facilitating the implementation of commercial delivery systems for these same tools in order to meet industry demand for their access. This paper presents the story of what was done over the past decade, it provides performance indicators of impact, it reflects on what was learnt over this period and it outlines where this research is likely to head in the future.Over the past 10 years, the FARMSCAPE team employed a Participatory Action Research approach to explore whether farmers could value simulation as a decision support tool for managing their farming system and if so, could it be delivered cost-effectively. Through farmer group engagement, on-farm trials, soil characterisation, monitoring of crops, soils and climate, and sessions to apply the APSIM systems simulator, FARMSCAPE represented a research program on decision support intervention. Initial scepticism by farmers and commercial consultants about the value of APSIM was addressed by testing its performance both against measured data from on-farm trials and against farmers' experiences with past commercial crops. Once this credibility check was passed, simulation sessions usually evolved into participants interactively inquiring of the model the consequence of alternative management options. These ‘What if’ questions using APSIM were contextualised using local climate and soil data and the farmer's actual or proposed management rules.The active participation of farmers and their advisers, and working in the context of their own farming operations, were the key ingredients in the design, implementation and interpretation of the FARMSCAPE approach to decision support. The attraction of the APSIM systems simulator to farmers contemplating change was that it allowed them to explore their own system in a manner equivalent to learning from experience. To achieve this, APSIM had to be credible and flexible. While direct engagement of farmers initially enabled only a limited number of beneficiaries, this approach generated a commercial market for timely and high quality interactions based on soil monitoring and simulation amongst a significant sector of the farming community. Current efforts are therefore focused on the training, support and accreditation of commercial agronomists in the application of the FARMSCAPE approach and tools.The FARMSCAPE approach to decision support has come to represent an approach to guiding science-based engagement with farm decision making which is being tested nationally and internationally.