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161.
茶叶品种、叶龄不同,其钙、镁、铁、锌等含量差异显著,并呈一定的分布规律;钙、镁比接近于1。  相似文献   
162.
中微量元素对番茄产量和品质影响的整合分析   总被引:3,自引:0,他引:3  
基于已有文献数据讨论了施用中微量元素对番茄单果质量、产量和品质影响的程度,以期为科学施用中微量元素肥料提供依据.研究数据来源于中国知网、万方数据和Web of science,以不施用中微量元素为对照,选择反应比作为效应值,通过Meta分析方法综合分析施用中微量元素对番茄产量和品质的作用效果,并分亚组进行讨论分析.整合...  相似文献   
163.
构建我国森林旅游生态补偿机制初探   总被引:4,自引:0,他引:4  
森林旅游业的发展可以保护森林景观和环境,同时也会对森林生态环境造成破坏。因此有必要建立森林旅游生态补偿机制,让旅游业更多参与生态保护和社区利益保障,实现旅游发展和森林生态环境保护、社区发展的动态平衡。从森林旅游生态补偿概念出发,阐述了构建我国森林旅游生态补偿机制的重要意义,重点分析了构建的核心要素,并提出了实施机制的有效保障体系。  相似文献   
164.
糙米是一种天然保健食品,由其制备的糙米茶和发芽糙米茶营养丰富,具有促进血液通畅、大便通畅、小便通畅、美容、减肥和防癌的作用。文章简述了糙米茶与发芽糙米茶的功效与制作方法,以期为今后开展糙米茶相关研究提供参考。  相似文献   
165.
砖红壤施用中量、微量元素对甘蔗产量与糖分的效应   总被引:10,自引:1,他引:10  
郭荣发  陈爱珠 《土壤》2004,36(3):323-326,330
在雷州半岛玄武岩发育的种植甘蔗砖红壤上施用Ca、Mg、B、Mo、Fe、Cu、Zn肥料,探究这些中量与微量元素对甘蔗的产量与糖分的效应。结果表明:Ca、Mg、B、Mo肥对甘蔗有显著增产效应,而Fe肥具有显著减产效应。B、Mo、Fe、Cu肥能显著提高甘蔗含糖量,而Mg肥具有降低甘蔗糖分的效应。Ca、B、Mo3种肥料相互配施的增产或增糖效果均不优于单施的效果。从对甘蔗产量和含糖量综合效果看,甘蔗施用B、Mo、Ca肥分别能产生显著经济效益。因此,在玄武岩发育砖红壤上种植甘蔗,建议施用Mo、B、Ca肥。  相似文献   
166.
With increasing agricultural and industrial use of rare earth elements (REEs), input of REEs into the pedosphere has risen in parallel. Since total REE budgets for soils in Germany are mainly unknown, this pilot study investigates the concentrations of REEs in three loess soil profiles under agricultural land use in the Wetterau region, Germany. There were no significant REE applications in the past, so the presented data can be considered as background concentrations of REEs in soils. In addition to the total REE contents (aqua regia digestion), potentially plant‐available (EDTA) and at actual conditions available, mobile (NH4NO3) REEs have been determined for each horizon. Interactions between REE availability and properties of soils are explained after assessing several chemical and physical properties. The results reveal a wide range of total REE contents, ranging from 222 to 423 mg kg–1. With 10.1% of total REE amounts, the potentially plant‐available proportions of REEs are generally low. In contrast, yttrium, which showed high available proportion of 24.8%, was found to be comparable with Cd. Cerium is the most abundant REE in aqua regia digests, whereas only small amounts in the potentially plant‐available fraction were found. Thus negative cerium anomalies could be concluded concerning its potential availability. Generally, bioavailability of REE had significant correlations between clay contents and Fe and Mn oxides for the majority of REEs. Due to moderately high pH (CaCl2) in soils (average 6.6) the mobile fraction for most of the elements was not detectible.  相似文献   
167.

Goal, Scope and Background

In the nineteen nineties most European countries issued legislation on soil protection, including soil contamination. In the case of a presumed contamination, soil investigation mostly follows a stepwise approach starting with a preliminary investigation, then an in-depth investigation and, finally, remediation. Soil clean-up standards are often foreseen as trigger criteria to determine the need for an in-depth soil investigation or for remediation. There are however large differences in soil clean-up standards. This is partly because of the different roles of soil clean-up standards in each legislative framework and partly because of differences in the soil clean-up standard (SCS) derivation procedures. Despites these differences there are large similarities in the concepts of the derivation procedures for clean-up standards. A better understanding of the differences in clean-up standards is needed. In order to clarify the variation, the background of the clean-up standards for a selected number of countries was investigated. The objective of this paper is to investigate the underlying reason why country-wide generic soil and groundwater clean-up standards of eight trace elements (cadmium, chromium (III), copper, mercury, lead, nickel, zinc and arsenic) differ between the selected countries.

Main Features

To avoid misinterpretation of the differences in application of the clean-up standards, a short overview of the legislative role of clean-up standards is given first. Differences in model concepts and parameter values are discussed, followed by a comparison of the generic soil and groundwater clean-up standards for trace elements and a discussion on the sources of variation. The influence of the use of ecotoxicological criteria and data for the derivation of soil clean-up standards will be discussed in more detail. Selected countries were Canada, the Flemish Region (Belgium), France, Germany, Great-Britain, the Netherlands, Norway, Sweden, Switzerland and United States of America (USA).

Results and Discussion

When soil clean-up standards for eight trace elements (cadmium, chromium (III), copper, mercury, lead, nickel, zinc and arsenic) were compared between the selected countries differences of more than a factor 1000 arose. Notwithstanding the use of similar derivation procedures, differences were caused by the use of different software models with their specific input data, boundary conditions and applied protection criteria for humans and the ecology. Ecotoxicological criteria tend to lower the soil clean-up standard for the selected trace elements.

Conclusions

In the countries that are included in this study, clean-up standards are used is different ways, this is for the determination of the necessity for remediation or for the need for further soil investigation. This paper shows a wide variation in the clean-up standards, which has further implication on the decision for remediation or further investigation and, hence, the financial costs of soil management. All the clean-up standards have as primary goal the protection of human health. A number of countries also include the protection of the ecological function of the soil. Differences in selected software model, (standard) parameters values, selected human toxicological and ecotoxicological criteria, are reason for a substantial variation in the clean-up standards for trace elements.

Recommendations and Perspective

. Is this variation justified? The derivation of soil clean-up standards involves - besides scientific elements - political elements, like differentiation in landuse types (agricultural, residential, recreational, industrial), receptor at risk or protection level. It is obvious that harmonization of these elements will be complicated. However, a European action programme, like the thematic strategy for soil protection, could initiate this process of harmonization. Nevertheless, soil-clean-up standards could never be uniform over the whole of Europe because they include country specific elements (geographical, ethnological) and political decisions.  相似文献   
168.
施亚琴 《林业研究》1994,5(4):49-51
INTRoDUCTIoNAnthasbeenusedasmedicineandhealthprotectionproductsfora1ongtime-Theant(PolyrhachisvicinaRoger)ismostincommon.TheyaremainlylivinginGuangxiProvince.Theyareablack,irri-tateacidityanddelicatefragranceinsects.ThereisakindofantinWandaMountain,Daxing'anMountain,andXiaoxing'anMountain.Itisabig(aboutmorethanl-ocmlong),strongandnonpollutioninsect.alotofbigandblackantswerecollectedfromWandaMountain.Itwasappraisedbyantexpertstobeantfami1yandantcategory.ItwasnamedFormicacuniculariaLa…  相似文献   
169.
以诸暨市体育公园为研究对象,通过测试夏、冬两个季节诸暨城市公园绿地不同样地的小气候要素数值,结合游人行为观测,探究了风、湿、热等小气候要素与人群行为间的复杂关系.结果发现:①高郁闭度对T HI有一定调节作用;②乔木、草本植物和水体蒸腾作用强,具有一定保湿作用;③灌木比高大乔木对风的阻碍更明显;④坐憩行为对小气候舒适度较...  相似文献   
170.
[目的]研究液面喷施硒对宁夏枸杞中微量元素积累的影响,促进富硒枸杞安全生产。[方法]以宁杞1号为供试材料,在枸杞叶面喷施亚硒酸钠,对枸杞中微量元素含量进行相关检测,研究喷硒对枸杞微量元素积累的影响。[结果]设定的0~500 mg/kg喷硒浓度范围,枸杞含硒量均有显著提高,喷施浓度及次数是影响枸杞硒含量的关键因素;铁、锌、锰、铜在硒不同施用量作用下,含量均呈现曲线变化。[结论]在一定浓度范围内,随着喷施浓度的增加,枸杞各微量元素含量在逐渐增加,超过耐受限量时呈下降趋势。  相似文献   
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