酒泉市耕地土壤养分状况评价

为了解酒泉市土壤养分状况。对酒泉市各县市的土样进行了养分测定。结果表明，酒泉市的农田土壤养分状况总体表现为有机质偏低，全氮和碱解氮中等偏低，速效磷和速效钾处于适宜和高水平。土壤pH总体为适宜和高水平。另外，各县（区、市）的土壤养分状况差异较大，均有一定比例的全氮、速效磷、速效钾等指标同时存在偏低或过高的现象。各县（区、市）应因地制宜，通过测土配方、合理施肥来提高土壤养分均衡供应能力，减少肥料施用量。     

庆城县耕地土壤养分含量现状及培肥改良对策

通过对2008年以来在庆城县耕地范围内采集的4000个耕层土样主要养分和主要微量元素含量状况的化验分析，并与全国第二次土壤普查数据进行比较，用养分分级的方法，判断庆城县耕地土壤机质贫乏、全氮极缺、有效磷偏低、钾较丰、微量元素普遍不足的养分现状。并提出了以增大土壤有机肥投入为前提，增氮稳磷调钾、补微加麯活土的配方施肥技术路线和土壤养分调控策略，为开展科学施肥指导和进一步培肥地力提供依据。     

海南省万宁市水稻土壤养分状况研究

为探明万宁市水稻土养分状况，采集3061个水稻土耕作层土样进行养分测定，并与第2次土壤普查数据进行比较分析。结果表明：土壤有机质和全氮含量属中等水平，并呈下降趋势；有效磷有较大幅度提高，速效钾也有所提高。但是有效磷钾含量不高，全市耕地土壤少磷缺钾状况依然存在。     

永春县水稻土肥力状况及其若干指标演变特点

根据2435个稻田耕层土样的常规5项,以及其中的400个代表性土样的土壤全量氮磷钾、有效钙镁硫和硼锌等养分肥力指标的测定结果,探讨永春县水稻土肥力状况,评价近30年来水稻土 p H、有机质、全氮和有效磷等肥力指标的动态变化特点。参照福建省稻田耕地养分肥力等级划分标准,结果表明,稻田土壤普遍出现偏酸现象,有机质含量总体处于中等水平;土壤供氮和供钾强度处于中等偏低水平,但土壤Olsen-P含量总体处于丰富状态;土壤供镁和供硫强度处于中低水平,有效硼含量处于严重缺乏状态,但土壤交换性钙和有效锌则为丰富。与第二次土壤普查结果相比,近30年来,全县土壤有机质和全氮平均含量分别提高了27.9％和32.1％,有效磷含量则平均提高了4.1倍,但全县水稻土呈现不同程度酸化现象,土壤p H平均从5.4下降到5.0。研究结果为永春县稻田因土施肥和具有针对性的土壤培肥技术提供了科学依据。     

测土配方快速检测技术在水稻生产上的应用研究

土壤养分测定，特别是土壤速效养分的测定是测土配方的前提，只有快速、准确地分析出土壤中的养分含量，才能做出正确的施肥决策。测土配方施肥是一项时效性很强的工作，必须在作物播种前做出施肥技术方案，所以高效快速地测定出土壤养分是测土配方施肥的关键。     

慧尔BB肥施用技术

测土配方是农作物施肥技术的重大改革。作为测土配方施肥最好的物质载体,慧尔牌 BB肥因土壤、气候、作物的需要随时调整氮、磷、钾比例。高效生态 BB 肥养分含量高、颗粒大,养分释放慢,利用率高、肥效稳长,因而损失少。慧尔牌 BB 肥加之配有"健康"营养元素,能增强作物抗病、抗虫能力,又减少了农药的用量和化肥施用不当造成氮、磷     

北京市测土配方项目实施区县土壤养分状况分析与评价

依据北京土壤养分分等定级标准,对2006年北京市密云、平谷和顺义3个区县测土配方施肥测定土壤数据进行了肥力分等,初步掌握了3个区县土壤养分状况,即平谷和顺义的土壤养分水平高于密云,平谷略高于顺义;3区县的土壤有机质水平基本处在中低水平上;土壤全氮养分均处于中等水平;土壤有效磷含量处于极低水平。另外,土壤种植类型和不同区域的种植结构和种植管理的规模化产业化程度对土壤养分的变异性有很大的影响,土壤磷钾养分的变异系数明显高于有机质和全氮指标。     

玉米生产中的测土配方施肥技术

测土施肥技术综合运用目标产量法、养分丰缺指标法和作物营养诊断法的优点。对于大田作物,在综合考虑有机肥、作物秸秆应用和管理措施的基础上,根据氮、磷、钾和中微量元素养分的不同特征,采取不同的养分优化调控与管理策略。其中,氮素用量推荐根据土壤供氮状况和作物需氮量,进行实时动态监测和精确调控,包括基肥和追肥的调控;磷钾肥用量推荐通过土壤测试和养分平衡进行监控;中微量元素使用应采用因缺补缺的矫正施肥策略。     

防城区耕地土壤养分变化动态研究

通过对防城港市防城区1980年第二次全国土壤普查、1998年配方施肥养分测定和2007年国家立项测土配方施肥项目耕地土壤养分测定结果分析,及对20多年来施肥量的比较,研究肥料施用和耕地土壤养分变化情况。结果表明,防城区耕地土壤养分变化较大,有机质、全氮、速效磷含量总体上呈上升趋势,但土壤养分含量极不平衡,必须重视用地养地,平衡施肥。     

东莞林科园土壤养分状况分析

依据对东莞林科园20个土壤剖面的调查取样，用电位法、碱解扩散法、氟化氨一盐酸浸提法、乙酸铵浸提-原子吸收法、重铬酸钾氧化-远红外加热法分别测定了土壤pH、速效N、速效P、速效K和有机质．在分析土壤养分总体特征的基础上，运用系统聚类的方法将东莞林科园土壤划分为6种养分类型：类Ⅰ为低肥力土壤；类Ⅱ为中氮土壤；类Ⅲ为高氮低磷土壤；类Ⅳ为富有机质的缺氮缺磷土壤；类Ⅴ属富磷高氮土壤；类Ⅵ属富氮土壤．其中，前3类是林科园的主要土壤养分类型．所划分的养分类型能反映各网格单元的地形特征及土地利用方式．     

改革求生存 创新谋发展——浅析地市级农业科学院(所)发展之路

地市级农业科学院(所)近年来,进行了一系列的科技体制改革,文章在论述以往改革的做法和成效的基础上,找出了改革中存在的几个影响发展的瓶颈问题,并进一步提出解决问题的对策。     

Hemagglutination by fava bean extract inhibited by simple sugars

Hemagglutination by extract of fava bean was inhibited by 5-percent d-glucose, d-fructose, or maltose, but not by 5-percent d-galactose or lactose. Failure to inhibit seems to reflect the presence of a hydroxyl group at the carbon No. 4 position. Hemagglutination was enhanced by dextran of high molecular weight, but not by dextran of low molecular weight. The finding supports the hypothesis that large molecular size explains the enhancement by gum acacia of hemagglutination by fava bean.     

Transformation by v-sis occurs by an internal autoactivation mechanism

Transformation by the v-sis oncogene appears to require an interaction of its protein product, p28v-sis, with the receptor for the platelet-derived growth factor (PDGF). However, this interaction may not occur at the cell surface as predicted by the autocrine hypothesis because phenotypic transformation was not reversed by incubation of SSV-NRK cells with antisera to PDGF and because morphological transformation did not occur when nontransformed NRK cells were cultured continuously with p28v-sis. A mutant of the wild-type v-sis gene was constructed that encodes a v-sis protein targeted for retention within the endoplasmic reticulum and Golgi. NRK cells expressing the mutant v-sis gene did not secrete any detectable v-sis protein but were as fully transformed as wild-type v-sis transfectants. The results support a mechanism of transformation by v-sis in which internal activation of the PDGF receptor occurs before expression of either p28v-sis or the PDGF receptor at the cell surface.     

Interferon: production by chick erythrocytes activated by cell fusion

In the presence of Sendai virus inactivated with ultraviolet light, nucleated chick erythrocytes can be fused with several types of human cells to form heterokaryons. Although chick erythrocytes alone cannot be stimulated by Sendai virus to produce interferon, fusion with a human cell (AH-1) which itself may produce human interferon results in heterokaryons in which the erythrocyte genome is activated and chick interferon is produced. When nucleated chick erythrocytes are fused with another type of human cell (HeLa clone S-3) which does not produce human interferon when stimulated, no chick interferon is detectable, despite morphologic changes suggestive of activation of the erythrocyte nuclei.     

Language discrimination by human newborns and by cotton-top tamarin monkeys

Humans, but no other animal, make meaningful use of spoken language. What is unclear, however, is whether this capacity depends on a unique constellation of perceptual and neurobiological mechanisms or whether a subset of such mechanisms is shared with other organisms. To explore this problem, parallel experiments were conducted on human newborns and cotton-top tamarin monkeys to assess their ability to discriminate unfamiliar languages. A habituation-dishabituation procedure was used to show that human newborns and tamarins can discriminate sentences from Dutch and Japanese but not if the sentences are played backward. Moreover, the cues for discrimination are not present in backward speech. This suggests that the human newborns' tuning to certain properties of speech relies on general processes of the primate auditory system.     

Hardening by annealing and softening by deformation in nanostructured metals

We observe that a nanostructured metal can be hardened by annealing and softened when subsequently deformed, which is in contrast to the typical behavior of a metal. Microstructural investigation points to an effect of the structural scale on fundamental mechanisms of dislocation-dislocation and dislocation-interface reactions, such that heat treatment reduces the generation and interaction of dislocations, leading to an increase in strength and a reduction in ductility. A subsequent deformation step may restore the dislocation structure and facilitate the yielding process when the metal is stressed. As a consequence, the strength decreases and the ductility increases. These observations suggest that for materials such as the nanostructured aluminum studied here, deformation should be used as an optimizing procedure instead of annealing.     

Ionization of liquids by radiation: measurement by charge scavenging

Pulse radiolysis of dilute solutions of triphenylcarbinol in saturated hydrocarbon gives spectra of the triphenylmethyl free radical, (C(6)H(5))(3)C., and cation, (C(6)H(5))(5)C(+). The yield of the ion is independent of the carbinol concentration, and is thought to measure the yield of free ions generated in the solvent. The relative yields of ions thus found in cyclohexane and 2,2,4-trimethylpentane agree with measurements made by the clearing-field method.     

依法治校与以德治校的思考

依法治校与以德治校是学校管理科学化、规范化的必须和标志。文章以实际工作中存在的一些问题为背景，就如何坚持依法治校与以德治校提出处理好若干关系的建议，指出依法治校是学校管理的保障和前提，以德治校是学校发展的灵魂和动力。