Excessive application of nitrogen and phosphorus fertilizers induces soil acidification and phosphorus enrichment during vegetable production in Yangtze River Delta,China

Intensive vegetable cultivation has developed very rapidly in China, and investigation of current soil nutrient problems in vegetable fields and their potential environmental risk is important for local soil nutrient management strategies. Three hundred and sixty‐six soil samples were collected from greenhouse vegetable fields, open vegetable fields and rice/wheat rotation fields in southern Jiangsu Province, the most intensive vegetable‐producing areas in Yangtze River Delta, China, for the analysis of their soil fertility status. Soil acidification and P enrichment were the main problems identified in this area of vegetable production, with about 20 and 17% of the open and greenhouse vegetable field soils, respectively, being extremely acid with soil pH values below 5.0. In contrast, no soils under rice/wheat rotation fields were as acidic. Percentages of sites with Olsen‐P concentrations < 90 mg/kg were 61, 85 and 0% for soils growing greenhouse vegetable, field vegetable and rice/wheat, respectively. The nitrogen (N) surplus for vegetable fields exceeded 170 kg/ha/crop, and the phosphorus (P) surplus exceeded 40 kg/ha/crop. Thus, current vegetable production leads to potential environmental risks of N and P pollution of nearby aquatic bodies. Insufficient supplementation with potassium fertilizers was found in some vegetable fields. Several ameliorative measures are proposed.     

立体栽培生产线系统开发

日光温室占我国设施园艺总面积逐年提升,但如今日光温室土地利用效率却相当低下。目前设计用来提高土地利用率的机器还相对较少。本设计通过在三维仿真软件Solid Works仿真后,主要提供了一种新的立体栽培生产线系统,该种植机械采用钢架结构,简单的链条传动,能满足栽培植物的需光量,并且能提高土地利用率至原来的2.1倍左右。     

广州公园绿地使用率研究--以广州烈士陵园和番禺新造镇公园为例

公园绿地是城市典型的开敞空间,对维护城市生态和人居环境健康、绿化和美化城市环境、加强市民间交往、营造平等和谐的社会气氛有着重要意义。公园绿地使用率体现了城市对居民的服务水平。文章运用实地考察、抽样调查、访问分析等手段,分析广州市公园绿地的使用率,并以广州起义烈士陵园和番禺新造镇公园为例进行说明。结果表明：可达性和安全性分别是影响中心城区和郊区公园绿地使用率的最主要因素。     

Economic potential of agroforestry for public recreational parks

The availability of public recreational facilities is being threatened by growing demands, limited supplies, and declining government funding. In response to these pressures, the economic potential of agroforestry for supplementing operating budgets of public recreational parks is examined in a case study park consisting of 324 hectares. Agroforestry enterprises native to the area were selected for development on 70 hectares of the site. Linear programming was used to determine the optimum combinations of 23 agroforestry regimes composed of the following activities: 1) conventional forestry planting, tree density of 1682 trees/hectare, 2) the selected agroforestry planting with hay, tree density of 1495 trees/hectare, 3) the selected agroforestry planting with grazing, 4) hay production, and 5) rental of pasture for grazing. The objective function of the study was to maximize the net present value of the study site subject to land, labor, capital, and minimum annual income constraints. The preferred optimal regime generated $1782 per hectare from an agroforestry planting configuration of 1495 trees/hectare with 75 percent hay, 25 percent grazing, and no annual income requirements. Minimum annual income requirements of $2400 and $4800 were feasible but suboptimal from a net present value criteria. The study found that agroforestry could be used to privatize selective activities of public recreational parks and thus enable public agencies to provide these facilities more effectively.     

Balancing Conservation and Economics

Summary

Ecotourism has been used successfully in many countries to promote economic well-being, conserve natural resources, and promote community development. A thorough examination of the factors that make a successful and unsuccessful ecotourism program was conducted in this paper. This analysis was performed in order to formulate recommendations for the development of an ecotourism program in the Panama Canal Watershed that will meet these objectives. A careful look at the conservation of natural areas, community development, and the economics of ecotourism fleshed out the good and the bad of existing programs. Case studies from other developing countries were used in order to set up criteria that should be used in Panama's blossoming ecotourism industry. Panama has a vast array of natural and cultural resources that can benefit from a carefully planned ecotourism program. When planning this initiative it is very important to take the politics of the country and communities into consideration, make sure the project is scaled to the carrying capacity of the natural resources and community involved, use existing infrastructure, train a skilled local work force, and maintain monitoring programs that ensure that an unsuccessful program be either improved or terminated.     

广州市越秀区街旁游园的景观设计探析

调查广州市越秀区街旁游园的建设情况,对各种类型街旁游园的设计原则、空间特征、小品、植物等景观要素进行分析。老城区街旁游园的设计规划应注意不同空间的营造与布局,创造动静结合、多功能、多层次的休闲空间,实现空间营造类型的多样化;园林小品与设施应布局合理和注重人性化;在植物设计上要体现岭南或者亚热带的植物风格特色。     

耐荫、半耐荫地被植物在广州公园中的应用

耐荫、半耐荫地被植物是营建复层植物景观的重要元素。在对广州公园进行调查研究基础上,文章归纳总结了耐荫、半耐荫地被植物的种类,并根据园林用途对其进行归类。共有34种,隶属25科33属。经分析,这些植物与其他园林要素之间常见的配置方式有路缘配置、与山石相配置等7种。     

海口主要公园香花植物资源调查与分析

香花植物在园林景观中满足了人们视觉感官与嗅觉感官的双重要求,有着独特的应用价值。本文对海口市5所大型综合性公园的香花植物进行调查,为推动其在海口市园林景观中的应用提供参考。研究发现,所调查的公园有香花植物45种（含1变种,2栽培品种）,隶属于29科39属,以乡土植物为主,木本植物居多;多集中于夏季开花,花色以白色为主;花香从微香型到浓香型,以芳香型为主;主要有闻香主景式、点缀配景式两种配置形式。另外,香花植物种类偏少、种植面积小、花色单调等问题突出,针对以上问题提出相应对策。     

营造生态园林 注重群落景观——上海市公园绿地植物群落探析

文章运用生态园林景观分类方法对公园绿地植物群落进行分类,详细介绍典型的植物群落,并指出当前存在的问题。本文从上海市100多个公园绿地中,选取具有代表性的上海植物园、延中绿地等14个公园绿地进行群落探析。