广西耕地土壤铜的含量及其影响因素

对2242个采自广西不同类型的耕地表层土壤样品进行有效铜含量分析,结果表明,广西耕地土壤铜的含量比较丰富,全铜含量在1.03~101.18m g/kg之间,平均27.41m g/kg,高于全国和世界平均含量;有效铜含量在0.01~19.19m g/kg之间,平均2.48m g/kg,低于0.2m g/kg缺铜临界值的土壤只占样点的0.49%;成土母质、土壤有机质、土壤pH值和土壤的农业利用方式是影响土壤有效铜含量的主要因素。     

基于DRIS法的水果型椰子黄化枯萎症和健康苗叶片营养诊断

为给水果型椰子苗期的科学施肥管理提供指导,以海南省文椰"3号"叶片为研究对象,采用DRIS指数法,对6个月椰子苗叶片的11种养分(氮、磷、钾、钙、镁、钠、铜、锌、铁、锰、硼)进行营养诊断.结果表明,枯萎椰子苗钾、硼、钙、镁、氮相对缺乏,锌、钠、铜、磷、锰、铁相对充足,椰子苗期(6个月)树体需肥顺序从高到低依次为钾>硼>钙>镁>氮>锌>钠>铜>磷>锰>铁.利用健康椰苗叶片养分浓度制定了相应的养分诊断标准,即各养分的适宜浓度范围为氮含量16.680～20.070 g/kg,磷含量1.170～1.360 g/kg,钾含量6.670～7.780 g/kg,钙含量4.170～4.550 g/kg,钠含量2.780～3.301 g/kg,镁含量2.930～3.470 g/kg,铁含量47.958～52.297 mg/kg,锰含量96.913～119.057 mg/kg,铜含量3.048～3.410 mg/kg,锌含量10.367～12.701 mg/kg,硼含量22.724～27.610 mg/kg.从DRIS法诊断结果来看,椰苗叶片矿质营养元素含量与椰苗"枯萎现象"之间密切相关.     

利川市耕地铜、锌、铁、锰有效态含量及其空间分布

检测、统计并分析了湖北省利川市604个耕地土样的pH和有效铜、有效锌、有效铁、有效锰及有机质含量。结果表明,利川市耕地土壤pH平均为6.21±1.15,变幅为3.95～8.58,变异系数为18.49%,属中等偏弱变异;有机质含量平均为(27.17±10.84) g/kg,变幅为5.39～88.50 g/kg,变异系数为39.90%,属中等变异。有效铜、有效锌、有效铁、有效锰平均含量分别为(1.39±1.31) mg/kg、(1.07±0.92) mg/kg、(58.84±52.67) mg/kg、(39.22±32.49) mg/kg,按辽宁省DB 21/T 1437-2006地方标准评价,有效锌含量中等,其他3种含量高;变幅范围分别在未检出至8.28 mg/kg、未检出至8.41 mg/kg、2.89～311.15 mg/kg、3.29～234.38 mg/kg;变异系数分别为93.99%、86.25%、89.52%、82.83%,皆为中等偏强变异;缺锌比例达63.57%,因此要加强锌肥的应用。耕地土壤有效铜、有效锌、有效铁含量与土壤有机质含量均呈极显著正相关;有效铜、有效锌、有效铁、有效锰含量与土壤pH均呈极显著负相关。初步摸清了利川市耕地有效铜、有效锌、有效铁、有效锰含量及在不同耕作方式、土类及不同成土母质发育土壤上的分布特征。     

原平市玉米种植区土壤微量元素与有机质和pH的关系分析

研究山西省原平市玉米种植区土壤微量元素含量情况及其与有机质和pH之间的关系，为当地玉米高产优质生产提供理论依据。根据研究区域玉米种植区划，采集了0～20 cm耕层土壤样品，测定土壤pH、有机质以及微量元素铜、锌、镍、铁、锰、硒和钙的含量，利用Pearson相关分析法和一元线性回归方法对土壤微量元素全量与有机质和pH的关系进行分析。结果表明，原平市土壤有机质含量为4.10～53.98 g/kg，平均值为17.29 g/kg;pH为7.50～8.66，平均值为8.08，表明原平市土壤有机质含量处于中等偏低水平。土壤中的微量元素铜、锌、镍、铁、锰、硒和钙含量的平均值分别为20.61 mg/kg、68.47 mg/kg、33.30 mg/kg、2.92%、578.13 mg/kg、0.28 mg/kg和4.07%，其中，锌、镍、锰、硒的平均值高于山西省背景值，铜、铁、钙的平均值低于山西省对应元素土壤背景值。铜、锌、硒含量与pH呈极显著负相关关系（P<0.01），铁含量与pH呈显著负相关关系（P<0.05），钙含量与pH呈极显著正相关关系（P<0.01）；锌含量与有机质呈极显著...     

欧李钙、铁、锌、硒含量测定分析及生态适应性观察

【目的】观察大欧李引种新疆昌吉州后其生态适应性及钙、铁、锌、硒等人体有益元素含量及变化,为欧李在新疆推广与利用提供基础理论数据支持。【方法】对大欧李生态适应性常规记录观察;利用美国VARIAN公司VITSTA-PRO光谱仪对欧李果实中的钙、铁、和锌含量进行测定;利用北分瑞利的AF-640原子荧光光谱仪对样品中硒含量进行测定。【结果】学院试验田成活率100%,次年成活率高达95%,榆泉现代农业示范中心当年成活率90%;两种果形钙、铁、锌、硒含量差异极显著,两种果形钙平均含量267.28 mg/kg,铁平均含量8.63 mg/kg,锌1.13 mc/kg,硒平均含量0.01 mg/kg。【结论】大欧李适应新疆昌吉州寒、旱、盐碱、瘠薄试验田,可正常生长发育,钙、铁、锌及硒含量较一般水果高几倍甚至十几倍。     

黔东南州稻田土壤中有效铁锰铜锌的含量

为黔东南州合理施用微肥提供依据,利用火焰原子吸收光谱法测定采自贵州省黔东南州16个县市稻田土壤有效铁、锰、铜、锌的含量。结果表明:在黔东南州16个县市稻田土壤中有效铁的平均含量为202.88 mg/kg,变异范围为1.38~478.88 mg/kg;有效锰的平均含量为38.97 mg/kg,变异范围为25.60~144.31mg/kg;有效铜的平均含量为6.63mg/kg,变异范围为4.45~8.29mg/kg;有效锌的平均含量值为11.07mg/kg,变异范围为4.57~21.85mg/kg。贵州省黔东南州稻田土壤中有效铁、锰含量处于高等水平,有效铜、锌含量处于中等水平。     

海南菠萝蜜种植园土壤与叶片微量元素含量分析研究

对海南不同区域菠萝蜜种植园土壤微量元素有效态含量及叶片中微量元素含量进行分析,旨在探明土壤、叶片微量元素含量差异及其丰缺等级,为营养诊断、科学施肥提供理论依据。结果表明:菠萝蜜种植园土壤有效态锰、有效铁、有效锌、有效铜含量分别为44.90、36.77、3.96、0.94 mg/kg,其中,有效态铁、锌、锰含量极丰富,有效铜处于适中水平;不同区种植园土壤微量元素有效态含量差异显著,万宁-陵水区含量较高,海口-文昌、三亚-乐东区含量适中。叶片锰、铁、锌、铜含量均值分别为458.37、71.25、23.89、2.69 mg/kg。海南菠萝蜜种植园叶片微量元素含量参考值适宜范围为全锌17.85~29.93 mg/kg、全铜1.67~3.72 mg/kg、全铁57.30~85.20 mg/kg、全锰323.33~593.41 mg/kg。     

豫中平原褐土、潮土、砂姜黑土养分状况分析及培肥措施

通过对豫中平原许昌市主要土壤类型褐土、潮土、砂姜黑土土壤有机质、全氮、有效磷、速效钾等大量元素和有效铜、铁、锰、锌微量元素的分析测定,探明豫中平原不同土壤类型养分现状,结果表明,豫中平原不同土壤类型潮土有机质、全氮、速效钾平均含量较低,分别为15.4 g/kg、0.98 g/kg、119 mg/kg,低于褐土和砂姜黑土。有效磷平均含量10.2~10.4 mg/kg,各土类含量相当,有效铜、锰、锌平均含量均为潮土最高。     

达州白肋烟植烟土壤中、微量元素含量分析及施肥对策

对达州白肋烟主产区宣汉县30个土壤样品的中量、微量元素含量进行了分析。结果表明:交换性钙、交换性镁和有效硫的平均含量分别为278.88、27.56和37.08 mg/kg;有效铁、锰、铜、锌、硼和氯的平均含量分别为63.72、55.96、0.19、2.11、0.15和91.81 mg/kg;该区植烟土壤交换性钙、交换性镁、有效铜及有效硼含量不足,有效硫、锌、铁、锰的含量总体上较丰富,氯含量偏高。在烟草生产上,要因地制宜,科学补充缺乏元素,禁止施用含氯肥料。     

河北省红地球葡萄土壤与叶片营养诊断分析

为科学指导河北省红地球葡萄主产区果园管理和平衡施肥,以河北省昌黎县葡萄主产区为试验地,以土壤(0～30 cm)和叶片为试验材料,通过测定土壤养分和叶片营养元素含量,明确丰缺状况并分析土壤和叶片的相关性.结果表明,土壤有机质平均含量为12.8 g/kg,64％处于低量及以下水平;硝态氮、有效磷、速效钾含量处于丰富水平的果园均大于70％,其中速效钾含量可达87％;有效锰含量平均含量为11.2 mg/kg,69％处于低-缺乏水平;有效铁和有效铜含量100％的点位处于适量及以上水平;有效锌含量80％为丰富水平,平均含量为3.5 mg/kg.高产组叶片中氮(N)、钾(K)、钙(Ca)、铁(Fe)、硼(B)元素平均含量为16.1 g/kg、24.5 g/kg、38.8 g/kg、52.2 mg/kg、27.5 mg/kg,均大于低产组;磷(P)、镁(Mg)、锰(Mn)、铜(Cu)、锌(Zn)元素平均含量为3.2 g/kg、4.5 g/kg、107.2 mg/kg、18.9 mg/kg、271.9 mg/kg,均略小于低产组.DRIS诊断结果确定叶片对Fe、Mn、Ca、Zn需求强度依次降低,Mg、B过剩.综合看来,葡萄园应注重增施有机肥和锰肥,控制钾肥用量,适量施用氮肥和磷肥,合理施用微量元素肥料.     

Alternatives, traditions, and diversity in agriculture

This review essay examines several recentbooks about agriculture, including two books on thelinks between cultural and biological diversity intraditional agriculture, two books on the US farmcrisis, and a collected volume examining globalaspects of agricultural restructuring andsustainability. Finally, a history of ``alternative'agriculture provides a framework for thinking aboutthe ways the different cases shed light on the complexrelations between tradition and innovation inagriculture. A historical perspective highlights theextent to which ``alternative' is a relative term. Themonocrop, ``factory' mode that dominate US agriculturetoday certainly differs from what has characterizedfarming for most of history and in most of the world.Small-scale, more or less organic, diversified farms,which appear so ``alternative' in the present context,have until lately counted as the norm, here andelsewhere. These books also highlight both the dangersof the currently dominant industrial agriculture andthe potential for genuine alternatives.     

Gallium, germanium, indium, and iridium in lunar samples

Neutron activation analyses of gallium, germanium, indium, and iridium in eight lunar samples and in meteorites and rocks (including four calciulnrich achondrites and five terrestrial basalts) with similar bulk compositions are reported. Lunar gallium concentrations are remarkably constant at about 5 parts per million, three times higher and four times lower than those in eucritic (calcium-rich) achondrites and terrestrial basalts, respectively. Lunar germanium concentrations range from 相似文献   

Structure, dynamics, and reactivity in hemoglobin

The static structure of hemoglobin and its functional properties are very well characterized. It is still not known how energy is stored and used within the structure of the protein to promote function and functional diversity. An essential part of this question is understanding the mechanism through which the overall protein structure (quaternary structure) couples to the local environment about the oxygen binding sites. Time-resolved resonance Raman spectroscopy has been used to probe the vibrational degrees of the freedom of the binding site as a function of protein structure. Comparison of the spectra from both equilibrium and transient forms of deoxy hemoglobin from a variety of mammalian, reptilian, and fish hemoglobins reveals that for each quaternary structure there exist two tertiary states stabilized by the presence or absence of an iron-bound ligand. Pulse-probe Raman experiments show that for photodissociated, ligated hemoglobins the local tertiary structure relaxes at a solution-dependent rate extending from tens of nanoseconds to microseconds. In this local environment, the linkage between the iron and the proximal histidine proves to be the single observed structural feature that responds in a systematic and substantial manner to structural changes in the protein. The additional finding of a correlation between the frequency of the iron-proximal histidine stretching motion (nu Fe-His) and various parameters of ligand reactivity, including geminate recombination, implicates the associated localized structural element in the mechanism of protein control of ligand binding. On the basis of these and related finds, a model is presented to account for both coarse and fine control of ligand binding by the protein structure.     

重金属Pb、Cr、Cd对烟草生长的影响及其分布规律

【目的】研究重金属Pb、Cr、Cd对烟草的生理作用及其在烟草中的吸收累积规律。【方法】采用盆栽试验方法，测定烟草根、茎、叶等器官中Pb、Cr、Cd含量，分析不同重金属污染程度下烟草的株高及叶片干物质重的变化。【结果】重金属处理的土壤中烟草的株高都显著低于对照，呈现抑制作用，添加外源Pb和Cr处理下，烟草叶片干重随添加浓度的升高而降低，Cd处理则呈现出先升高后降低的趋势。Pb、Cr、Cd重金属在烟草器官中的含量均为根＞茎＞叶，根系中Pb、Cr、Cd的浓度与添加浓度具有较好的相关性，而叶片中只有Cd含量与添加浓度具有较好的相关性。【结论】烟草植株中的重金属主要来源于土壤，烟草对重金属的传输过程具有一定的滞阻作用。     

Potassium, rubidium, strontium, barium, and rare-Earth concentrations in lunar rocks and separated phases

Concentrations of potassium, rubidium, strontium, barium, and rareearth elements have been determined by mass spectrometric isotope dilution for eight Apollo 11 lunar samples and for some separated phases. Potassiumn and ritbidium are at chondritic levels, strontium at 15 times, and barium and rare earths at 30 to 100 times chondritic levels. There are trace element similarities between the lunar samples and basaltic achondrites, terrestrial dredge basalts and the bulk earth. The trace element data appear to be consistent with these lunar samples being the result of limited partial fusion of some material similar to the brecciated eucrite meteorites.