Essential Factors and Sustainable Development of Green Agriculture

This paper discussed the definition and essential factors of green agriculture, including green ecological environment, green material energy input, application and the popularization of green agricultural technology, the green behavior of worker, green policy regulations guarantee, fund support, supply and the production of green agriculture products, as well as the concept of green agriculture, structural mechanism and function. And finally existing problems in present green agriculture and five suggestions of green agricultural sustainable develonment were proposed.     

国外绿色农业科技信息资源建设与启示

分别从绿色农业科技信息网站、数据库、多媒体服务平台、科技咨询、研究机构和专业协会合作组织等几个方面深入研究了国外绿色农业科技信息资源建设情况及成功经验,提出了对北京市相关工作的对策建议。     

浅议我国绿色旅游

文章探讨了我国绿色旅游的兴起、内涵、特点和功能等,讨论了绿色旅游、生态旅游、自然旅游的区别与联系,分析了我国绿色旅游的发展现状和对策。     

一类空间分解问题

讨论了一类与区域分解算法有关的空间分解问题，将二阶问题的已有的空间分解结果推广到四阶问题的相应空间中。还证明了一致重迭性条件与Ｂａｄｅａ条件的等价性。     

Effect of Integration of Fertilizer and Green Manure Nitrogen on Yield Attributes, Nitrogen Uptake and Yield of Lowland Rice (Oryza sativa L.)

Field experiments were conducted at Tamil Nadu Rice Research Institute, Aduthurai, India, during the wet seasons of 1992 and 1993 to study the effect of full and partial substitution of fertiliser N with green manure N (Sesbania rostrata) on nitrogen uptake, yield attributes and yield of rice. The experiment consisted of eight treatments with two levels of N (100 and 200 kg ha⁻¹) and three sources of N application viz., fertilizer, integrated (1:1 fertilizer and green manure N) and green manure N compared to the recommended practice (150 kg fertilizer plus 6.25 t ha⁻¹ (72 kg N) green manure) and a no N control. Nitrogen application markedly increased the N uptake. Combined use of the two N sources at 200 and 222 kg N ha⁻¹ and of single fertilizer N at 200 kg N ha⁻¹ recorded the maximum N uptake, increased the yield attributes such as number of panicles per unit area, weight per panicle, number of total and filled grains per panicle and test weight. At 200 kg N ha⁻¹ full substitution of N by green manure reduced the grain yield but only partial substitution of N by green manure resulted in almost similar yield as single fertilizer N. Thus 200 kg N ha⁻¹ applied in equal proportions of fertilizer and green manure N can be recommended for medium duration rice cultivars.     

开发城市地下空间前景广阔

本文介绍了开发城市地下空间的必然趋势及前景，阐明开发利用城市地下空间，对节省城市用地、节约能源、改善城市交通、减轻城市污染等都有着重要作用。     

黄河下游影响带地下水系统动力学特征

以黄河下游影响带地下水系统为例,介绍了地下水系统的动力学特征分析方法,计算了其动力学特征指标:Hurst指数为0.91~0.97、Kolmogorov熵为0.054~0.081、最大Lyapunov指数均大于零、分维数为2.50~3.36。分析结果表明:黄河下游影响带地下水系统的各子系统都具有混沌性;Hurst指数刻划了系统的开放程度和受外界干扰程度;分形维描述了非线性系统的复杂程度。     

城市公园绿地边缘效应及其影响研究

城市公园绿地与城市其他景观系统的交界处存在着边缘区,边缘区特殊的位置形成了不同于绿地内部的小环境,产生了边缘效应。边缘效应不仅影响公共绿地园林植物群落的稳定性,同时破坏了公共绿地景观的美观,边缘效应对城市公共绿地的作用还没有引起足够重视。通过对成都市东湖公园绿地边缘的植物调查,初步探讨了城市公园绿地的边缘效应及其产生的影响,并对抑制城市公园绿地边缘效应的影响提出了建议。     

城市慢行空间美景度评价 ——以贵阳市小车河沿河河谷慢行空间为例

以贵阳市小车河沿河河谷慢行空间为研究对象,通过实地调查选取能够较好地反映慢行空间景观特征与景观效果的20处景观样点作为评价对象,运用基于心理物理模式的美景度评价法计算景观样点的美景度值,再通过景观要素分解量化得到景观要素评值,运用回归分析建立慢行空间美景度评价模型,进而对慢行空间美景度进行评价.结果表明,形态优美、具有...     

小西葫芦绿斑驳花叶病毒生物学特性及传播方式

小西葫芦绿斑驳花叶病毒(Zucchini green mottle mosaic virus,ZGMMV)是我国新报道的侵染葫芦科作物的烟草花叶病毒属病毒.从感染病毒的葫芦叶片中分离出ZGMMV,摩擦接种西瓜(Citrullus lanatus)、葫芦(Lagenaria siceraria)、西葫芦(Cucurbit...