名山河流域黄壤组分对微团聚体吸附解吸镉的影响

选取名山河流域4种土地利用方式（林地、水田、茶园、旱地）的黄壤为研究对象,采用平衡液等温吸附法和NH4OAC、EDTA溶液解吸法,研究土壤组分（有机质、游离氧化铁）对微团聚体吸附解吸Cd2＋的影响。结果表明：去除土壤组分前后,原土及各粒径微团聚体对Cd2＋的吸附量均随Cd2＋初始浓度增大而增大,吸附量均按以下次序递减：（〈0.002mm）〉2～0.25mm〉原土〉0.053～0.002mm〉0.25～0.053mm,与有机质、游离氧化铁、CEC呈极显著正相关。吸附减少量大小关系为：去除有机质〉去除游离氧化铁,有机质的贡献率大于游离氧化铁。Freundlich方程拟合效果最佳,达到极显著水平,分布系数Kd值与Cd2＋初始浓度呈曲线负相关。NH4OAC解吸率随原吸附Cd2＋初始浓度增大而增大,以最大解吸率计,递减规律为：0.25～0.053mm〉0.053～0.002mm〉原土〉2～0.25mm〉（〈0.002mm）;EDTA解吸率随原吸附Cd2＋初始浓度增大而减小,递减规律与NH4OAC解吸率相反。去除土壤组分后,NH4OAC解吸率上升,EDTA解吸率下降,茶园与旱地黄壤非解吸率减小,林地与水田黄壤非解吸率增大。去除土壤组分后,非专性吸附与吸附总量呈极显著正相关,专性吸附与吸附总量呈极显著负相关。     

景观植物管理信息系统的初步构建

景观植物管理查询系统(LandscapePlantManagementInformationSystem,LPMIS)是一种管理信息系统(MIS[1,2])。LPMIS采用面向对象的开发语言VisualBasic6.0和桌面数据库管理系统Access,在Windows操作系统环境下开发而成。LPMIS具有可视化、人性化的界面,能提供多媒体信息,数据的维护和更新具有继承性,后台数据库可方便的移植于网络;LPMIS具有较好的可移植性和通用性,通过更换后台数据库,LPMIS可方便的应用于其他领域并开发出不同的数据库。LPMIS可促进景观植物数据的查询和管理,加快从手工向自动化的变革,从而大大提高工作效率。     

采用VB6.0构建农药信息专家系统

农药信息专家系统主要由五大模块组成:病虫草识别、农药品种、农药处方、合理用药、供求信息。采用Microsoft Access 2002关系型数据库管理数据,以Visual Basic 6.0为开发语言进行程序设计。系统根据用户输入的查询要求,向用户提供病虫草害防治处方、农药理化性质、毒性、作用特点和注意事项等信息。系统智能性强,模糊查询性能优越,收集的资料较全面,可供在生产实践中直接应用。     

基于VB.NET的农业害虫专家系统软件开发

针对农业生产中害虫防治的需要，建立昆虫信息数据库，为农业害虫的鉴定和防治提供帮助与支持。介绍了“农业害虫专家系统”的概念和基本结构，着重描述了农业害虫专家系统开发过程中的关键技术。     

Urban greenspace access,uses, and values: A case study of user perceptions in metropolitan ravine parks

Urban greenspaces provide critical ecosystem services to urban area residents. While urban greenspaces provide a range of ecosystem services, cultural ecosystem services may be the most prominent to residents. Cultural ecosystem services provide benefits through educational, recreational, social, and spiritual opportunities. More knowledge is required about greenspace users’ perspectives of their local greenspaces, which will enrich park planners’ knowledge of the preferences, concerns, and potential points of conflict that greenspace users experience. To help increase this knowledge, we conducted a survey with closed and open-ended questions and supported it with a park audit and photographic evidence. As a case study, data were collected in six ravine parks in the City of Toronto, Canada. Ravine parks were of particular interest as they are a unique form of socio-ecological greenspace that have varied management goals which on occasion may differ from some user preferences and values. Quantitative data were analyzed with analysis of variance and chi-square tests of independence, and qualitative data were analyzed with conventional qualitative content analysis. Our results highlight that current ravine park users vary widely in their characteristics and the values they pursue through their park access. While the range of ravine park types accommodates some of this variability, there is also conflict between ravine park users with different values and expectations. We are offering a series of recommendations addressing these findings and hope that insights from this deep and rich case study will be of use to other forested, urban greenspaces under similar conditions.     

甘肃啮齿动物Web信息系统设计与实现

通过查询、整理和分析文献资料,结合实地调汇、参与式农牧民调查以及请教有关专家等方式,系统收集了甘肃啮齿动物的区系组成、形态特征、分类地位、种群动态、地理分布、测报模型及防控措施等大量信息资料,并以此支撑建立甘肃啮齿动物数据库。采用ASP技术,以SQL Server 2000为数据库平台,设计开发了甘肃啮齿动物Web信息系统。本系统是由后台甘肃啮齿动物信息数据库、前台用户查询系统及管理员信息管理系统共同组成的综合系统,采用Browser/Server 模式,实现了甘肃啮齿动物信息的管理科学化和共享化。     

乡(镇)级农业生资电子商务平台的设计

文章针对黑龙江省当前农业生产资料流通体系中存在的问题,提出乡(镇)级农业生资电子商务平台的设计。电子商务平台采用B/S/D三层体系结构开发,利用微软的Web开发技术ASP.NET调用后台数据库中的数据,实现网上交易农业生产资料。     

涉农企业网络信息化技术集成与应用研究

本文主要介绍了采用ASP与ACCESS数据库技术设计的涉农企业网站及后台管理系统开发工具,可为涉农企业建立网站并进行管理维护,重点介绍了实现技术和应用功能。     

通用在线考试系统的开发

介绍了一种基于．NET的通用在线考试系统,采用三层B／S体系结构,融合了ASP．NET、C#和SQLSERVER2000技术来实现,分析了考试系统的几个关键技术,并充分考虑了系统的安全性设计。     

Snag density varies with intensity of timber harvest and human access

Many species of vertebrates depend on snags (standing dead trees) for persistence, and limited research suggests that snag density is lower in areas of intensive timber harvest and increased human access. While intensive timber harvest is one source of potential snag loss, ease of human access to forest stands may also facilitate loss via firewood cutting of snags. Accordingly, we hypothesized that density of snags (number of snags/ha) would decline in forest stands with increasing intensity of timber harvest and increasing ease of human access. We tested our hypothesis by sampling stands under varying levels of timber harvest and access on National Forest land in the northwestern United States. Stands with no history of timber harvest had 3 times the density of snags as stands selectively harvested, and 19 times the density as stands having undergone complete harvest. Stands not adjacent to roads had almost 3 times the density of snags as stands adjacent to roads. Unharvested stands adjacent to non-federal lands and closer to towns had lower snag density, as did stands with flat terrain in relation to nearest road. Our findings demonstrate that timber harvest and human access can have substantial effects on snag density. Meeting snag objectives for wildlife will require careful planning and effective mitigations as part of management of timber harvest and human access.