Land resources potential and sustainable land management: an overview

Land degradation continues to be a major threat to local and national food security. With limited potential to develop new land, any increase in agricultural production must be sought largely through the better use of land already under cultivation. Concerns for the global environment associated with agriculture worldwide have also increased in recent years and require more coordinated efforts at global and national levels with decentralisation of activities at the local level.
This article presents an overview of land resources potential for food production, the processes and extent of land degradation and its economic and environmental costs and impacts, and highlights some macro-economic policies and institutional measures for the prevention of land degradation and rehabilitation of degraded lands. A people-centred programme is presented as a basis for decentralising activities for sustainable land use and land management. Finally, the need for better coordinated efforts of concerned UN, multinational agencies and NGOs for the implementation of Agenda 21 and related conventions is stressed.     

四川省海桐花属药用植物的种类与分布

本文介绍了四川省海桐花属药用植物13种1变种的民间疗效和生境分布;首次报道密脉海桐为四川省分布新记录,并列有四川海桐花属药用植物的分种检索表。     

区域优势自然资源的评价——以河南省黄河两岸地区为例

本文试图从区域、自然资源本身和资源的外部条件出发,通过分析区域优势自然资源的概念,选择建立了衡量区域优势自然资源的6项标准体系,并以河南省黄河两岸地区为例,借助与高层次区域的比较研究,确定了该区域的优势自然资源是:铝土矿为第一优势资源,天然气为第二优势资源,以下资源次序为石油、煤、金矿、水泥灰岩、耐火粘土和水资源等。这为合理开发区域优势自然资源提供了重要科学依据.     

川西北两栖爬行动物资源及其利用与保护

川西北地区位于青藏高原东南部,现有两栖爬行动物67种(亚种),其中两栖类28种,爬行类39种;珍稀、濒危种约占22.4%,经济意义大、有利用价值的种占29.8%,经济意义一般的种占47.8%。这些动物在科研、工艺、药用、维护生态平衡等方面均有一定意义。本文对这些动物的利用现状作了评价,并对资源保护提出5点建议。     

EFFECTS OF LOMA PRIETA EARTHQUAKE ON SURFACE WATERS IN WADDELL VALLEY1

ABSTRACT: Waddell Creek is a perennial stream near Santa Cruz, California, which discharges into the Pacific Ocean about 38 km from the epicenter of the Loma Prieta earthquake (October 17, 1989, M 7.1). The earthquake caused no significant changes or damage to structures or surface features in the area, but was followed by an order of magnitude transient increase in discharge of Waddell Creek and nearby springs. The transients approximate a step rise followed by an exponential recession with time constants of from 37 to 59 days. The flow recession pattern of Waddell Creek was obscured by heavy rains after about 50 days; however, the springs maintained an exponential recession with minimal rain interference for periods of several time constants, then abruptly ceased flowing. A comparison of the pre-quake and post-quake chemical signature of one of the springs shows only minor changes in water chemistry indicating a common source for pre- and post-quake waters. Increased permeability of the subsurface ground material appears to be the most probable cause of the hydrologic changes. Post-seismic reduction of permeability has not been observed or inferred.     

四川省中药资源特征与开发利用研究

四川省中药资源具有种类多,蕴藏量大,水平分布和垂直分布明显,地道药材质量好,民族药物丰富和栽培药材产值高等特点。1986年统计,全省有中草药4550种。其中,植物药3962种,动物药344种,矿物药44种,产量和产值均约占全国的1/10。四川省在开发利用中药中,存在着资源蕴藏量不清、常用中药减少、产销失调、加工能力低等问题。建议在中药开发利用机构、决策系统、资源政策、生产经营和保护方面采取措施,合理利用中药资源。     

营口-海城地震活动特征总结

本文利用营口市地震台记录到的地震资料,对1975年海城7.3级地震和1999年海城岫岩5.4级地震的活动特征及地震地质背景进行分析.认为这两次地震同属一种类型在不同地段上的地壳应力在不同时间的释放.从中找到它们之间共同的活动特征以及不同之处,这对于本地区地震分析能够起到一定作用.     

川西草原十字花科油料植物资源的研究和利用

首次对四川西部草原的野生十字花科油料植物资源作了比较系统的调查研究,收集植株和种子标本约12属20种。经过种子油分分析和引种观察,筛选出几种有特种用途且适应力较强的植物资源。这些植物资源是蕴藏量大的食用油料播娘蒿(Descurainia sophia)、菥蓂(Thlaspi arvense),高亚油酸的优质食用油料植物高蔊菜(Rorippa elata),高亚麻酸的工业用油料植物涩荠(Malcolmia africana)、独行菜(Lepidiumapetalum)等。可供进一步的开发利用。     

采煤塌陷区重金属污染水体修复技术探讨及展望——以唐山市南湖公园为例

以唐山南湖公园为例综述了采煤塌陷区水体重金属污染的来源、危害及修复技术,详细介绍植物修复技术,总结了采煤塌陷区重金属污染水体修复技术的发展趋势和方向.     

沿海农田林网建设关键技术的经济学择优

对江苏沿海地区农田林网的经营类型、造林树种、林带配置进行了技术经济学分析和多目标灰色局势决策择优。结果表明：农田林网经营类型宜选择复合经营的果材兼用型林网。造林树种可选择速生丰产的杨树等用材树种和经济效益高的桃树等果树。林网配置在海堤河岸上选择用材树种，营造基干林带，筑起大网格框架；在道路沟渠上立体配置林果树种，营造主林带和副林带，构建中网格；在脱盐排水沟上添加果树辅助林带，建立小网格，形成多树种多林种合作、大中小网格配套、多道防线联防、多效益多产品产出的复合配置模式。