共查询到20条相似文献,搜索用时 343 毫秒
1.
甘肃是中国最贫困的省份之一。本文从生态环境恶劣,贫困人口压力大,耕地少.劳动生产率低,科技含量低,市场化低,产业结构严重失衡,劳动力增长快,人力资本积累少,富余劳动力转化率低,物质存量少,农产品商品化率低,农业生产仍停滞在自给自足的生存性消费阶段的“焦点”进行了分析。用持续发展的观点,以治本为主的途径等方面,对甘肃农民摆脱贫困的途径作了一些探讨。 相似文献
2.
没有证件的人不曾活过 一来到这个世界上,我们就与证件紧密地联系在一起了,也就是与一些数字组合和年月日捆绑在了一起.每过一年,我们的证件年龄就要改写一次,直到隆重地或无声无息地死去.而死去那一天,一切证件都要注销.贾平凹先生曾用一串数字介绍自己:"贾平凹,男,陕西省丹凤县棣花乡人,生于1952年2月21日,属龙相,身高1.65米,体重62公斤,1975年毕业于西北大学,分配于陕西人民出版社任文学编辑,1980年至今在西安市文联供职.单位邮政编码710069,地址莲湖巷2号,……犹如商店里出售的那些饮料,包装盒上就写满了种种成分的数字." 相似文献
3.
4.
5.
6.
不同土地利用方式下球囊霉素相关土壤蛋白与有机碳及土壤质地的关系 总被引:4,自引:0,他引:4
[目的]揭示土地利用方式对球囊霉素相关土壤蛋白(GRSP)的影响.[方法]测定了海南岛5种主要土地利用方式下GRSP、土壤有机碳(Soil oaganic carbon)与土壤质地(Soil texture)在0~10、10~20、20~50cm3个土壤层次中的分布情况.[结果]相对于保持较好的次生林,4种不同耕作土壤的GRSP与有机碳含量均有所下降.GRSP在海南岛5种主要土地利用方式土壤中的含量为0.53~4.80 mg/g,占有机碳的百分比为7.9%~23.4%,是碳库的重要组成部分.GRSP占有机碳的比例在不同土地利用方式下差异显著,在土层之间差异不显著,GRSP和有机碳含量在土壤剖面上垂直分布较明显.GRSP与有机碳、砂粒含量呈显著正相关,与粉粒和粘粒呈显著负相关.[结论]砂粒含量在很大程度上决定了CRSP的含量,壤土相对粘土更有利于GRSP的累积.
Abstract:
[Objective] The aim was to reveal the effects of different land use types on soil composition.[Method]GPRS,Soil organic carbon content and soil texture in 3 depths(0-10,10-20,20-50 cm)of 5 main kind of selected land use type were examined in Hainan. [Result] The results showed that GRSP and SOC content of four artificial land use types decreased compared with the natural sacondary foreSt land,the GRSP content of all samples ranged from 0.53-4.80 mg/g,accounting for 7.9%-23.4% of the SOC,which means that GRSP was one important component of SOC pool in soil.The ratio of GRSP to SOC was signiflcantly different among land use types but the depths.GRSP and SOC exhibited obvious vertical distribution pattern.GRSP was significantly positively related to SOC and sand content but negatively related to silt and clay content. [Conclusion] The sand content determined the GRSP content significantly and Joarn was better matrix for GRSP accumulation than clay. 相似文献
7.
以黔江区为研究对象,通过对生态环境影响因子的分析,发现制约黔江区土地利用环境发展的因素主要有区域气候变化、土壤要素、水文环境以及水土流失和土地退化等.并任以上分析的基础上,进一步分析了土地利用变化对生态环境的影响和制约黔江生态环境及区域发展的因素,最后提出了适应山区土地利用与生态环境协凋的对策,对黔江社会经济发展和生态建设具有重要意义.
Abstract:
Accompanying the development of social economy,the land use model of mountainous area,typically eco-weak area,is changing gradually.Here the establishment of eco-friendly land use model in mountainous area,will pioneer the model of sustainable development in that area.Concerning Qianjiang District of Chongqing Municipality,huge change of land use model,mainly embodied in the unceasing increase of construction land and gradual decrease of agricultural use land,has taken place in recent years.To explore the eco-friendly land use model in mountainous area,Qianjiang District was chosen as the study object in the present study.Via analyzing the changes in land use model,we found that related eco-environment restrictive factors mainly regional,climatic change,soil texture,hydrological environment as well as soil erosion and land degradation,etc.And based on these results,we further analyzed the effect of land use change on eco-environment and the factors restricting the maintenance of eco-environment and regional development,finally put forward the counter measures for balancing land use and co-environment in mountainous area.The results will be important for the development of social economy and eco-system construction in Qianjiang District. 相似文献
8.
前不久,康多莉扎·赖斯被小布什总统提名接替辞职的国务卿鲍威尔.如今50岁的赖斯成了美国第一位女黑人国务卿,同时也被世界公认是"美国最有权力的女人",甚至专栏作家在权威媒体<纽约时报>上预测,赖斯有可能"飞得更高",她或许将在2008年成为美国第一任女黑人总统.最近有消息也说,布什总统已决定让其弟与赖斯搭档参加2008年大选. 相似文献
9.
The vadety "Aifeng" was used as experimental matedal,and the stem diameter,plant height,the number of leaves and yield of P.vulgaris under three ways of ridge culture (bedding,high ridge and M ridge) were observed and detected to study the effects of different ridge cultures on the growth and yield.The results showed that the stem diameter,plant height,the number of leaves and yield under M ridge culture were higher than that of bedding and high ridge. 相似文献
10.
11.
室内测定了丙草胺分别与磺酰脲类除草剂甲磺隆、苄嘧磺隆、醚磺隆和吡嘧磺隆混用后,一叶一心期稻苗抑制50%株高的使用浓度(IC50)和抑制10%株高的使用浓度(IC50),并用共害系数(CHC)对混用组合安全性的联合作用进行了评价.结果表明:所有混配处理的CHC10均小于12.0,表现出强烈的解毒效应;不同混用处理的CHC50值差异很大,丙草胺与甲磺隆混用的CHC50均小于25.0,解毒效应显著.丙草胺与苄嘧磺隆混配的CHC50为26.1—167.8,丙草胺与苄嘧磺隆混用的CHC50为52.2—115.5,丙草胺与醚磺隆混用的CHC50为80.0—110.2. 相似文献
12.
试验研究了0~8周龄肉仔鸡胴体与羽毛蛋白、脂肪的生长曲线及0~3、4~6和7~8周龄3个阶段每日摄入不同水平的能量及蛋白对其体蛋白、体脂肪沉积的影响,旨在确定胴体与羽毛蛋白、脂肪动态的沉积规律及日粮能量沉积为体蛋白及体脂肪的效率。试验1,包括3个饲养试验分别选取体重相近的0、21和42日龄爱拔益加(AA)肉仔鸡324只,按性别及日粮随机分为18个处理,每处理3个重复,每重复6只鸡。肉仔鸡每日限量饲喂,饲喂水平分别为正常采食量的90%、70%和50%,每日定量供给肉仔鸡高、中、低3个水平的高蛋白质基础日粮及由饲喂水平决定的定量淀粉,进而使肉仔鸡每日采食能蛋质量比(代谢能/粗蛋白)不同的9种日粮;试验2,选取体重相近的0日龄AA肉仔鸡144只,按性别不同随机分为2个处理,每处理4个重复,每重复18只鸡。试验初和试验末分别进行屠宰,以测定肉仔鸡胴体和羽毛蛋白、脂肪和干物质含量。结果显示:1)Gompertz方程能很好的拟合不同性别肉仔鸡蛋白和脂肪的生长,不同性别间蛋白和脂肪极限重量、羽毛蛋白和脂肪的生长速率差异显著(P<0.05),而胴体蛋白和脂肪的生长速率差异不显著(P>0.05)。2)在0~3、4~6和7~8周... 相似文献
13.
ICP-OES法同时测定果蔬中铅、砷、镉、铬、铜、锡含量 总被引:2,自引:0,他引:2
果蔬样品经混酸消化后,控制一定的酸度,定容后应用等离子体发射光谱法(ICP-OES)对果蔬中铅、砷、镉、铬、铜、锡六种有害重金属进行测定,研究了分析测定条件,方法简单快速。测定结果表明,五种元素的加标平均回收率在91.0%~107%之间。其RSD均小于3.5%。按该方法进行处理及测定铅、砷、镉、铬、铜、锡,在选择的测定条件下最低检出限分别为0.0006 mg/kg、0.0003 mg/kg、0.00003 mg/kg、0.00005 mg/kg、0.00003 mg/kg、0.0006 mg/kg。 相似文献
14.
Characterisation of Neonicotinoid and Pymetrozine Resistance in Strains of Bemisia tabaci (Hemiptera: Aleyrodidae) from China
下载免费PDF全文
![点击此处可从《农业科学学报》网站下载免费的PDF全文](/ch/ext_images/free.gif)
RAO Qiong XU Yong-hua LUO Chen ZHANG Hong-yu Christopher M Jones Greg J Devine KevinGorman Ian Denholm 《农业科学学报》2012,11(2):321-326
Four strains of the Q biotype and one of the B biotype of the whitefly Bemisia tabaci collected from China were characterised for resistance to four neonicotinoid insecticides and pymetrozine. Q biotype strains showed moderate to strong resistance to imidacloprid, thiamethoxam and acetamiprid, but little or no cross-resistance to dinotefuron. Resistance to neonicotinoids was consistently associated with resistance to pymetrozine, despite the latter having a distinct (though unresolved) mode of action. The single B biotype strain proved largely susceptible to all the insecticides investigated. Resistance in the Q biotype strains was associated with over-expression of a cytochrome P450 monooxygenase gene, CYP6CM1, whose substrate specificity presumably accounts for the observed cross-resistance profiles. 相似文献
15.
16.
据作者近年来实地调查,采集标本,归纳了新疆地区的野生观赏植物,观赏价值较高者共有54科117属392种。 相似文献
17.
[目的]研究烘烤对不同部位烟叶微生物种群的影响。[方法]采用不同的培养基分离鉴定烘烤过程中烟叶上的微生物,调查在烟叶烘烤过程中微生物种群的变化。[结果]在新鲜烟叶上,微生物种类是下部叶比中部叶多,上部叶上的微生物种类相对最少。烟叶经过烘烤后,不同叶位烟叶上的微生物种类明显少于新鲜烟叶。烟叶在烘烤进程中,细菌种类一直在减少;放线菌在定色期有所增加;中、下部烟叶的霉菌在烘烤过程中减少,而在上部烟叶霉菌在变黄、定色期增加,然后在干筋期减少。[结论]该研究可为预防烟叶在烘烤过程中腐烂和提高烟叶品质提供科学依据。 相似文献
18.
19.