Cash cropping and food crop productivity: synergies or trade‐offs?

The case for promoting export‐oriented cash crops in Africa has generally been based on their direct potential contribution to agricultural productivity and small farmer incomes. A relatively neglected avenue of research concerns the synergistic effects that cash cropping can have on other household activities, including food production. The conventional view that cash crops compete with food crops for land and labour neglects the potential for cash crop schemes to make available inputs on credit, management training, and other resources that can contribute to food crop productivity, which might otherwise not be accessible to farmers if they did not participate in cash crop programs. This article builds on previous research by hypothesising key pathways by which cash crops may affect food crop activities and empirically measuring these effects using the case of cotton in Gokwe North District in Zimbabwe. Analysis is based on instrumental variable analysis of survey data on 430 rural households in 1996. Results indicate that—after controlling for household assets, education and locational differences—households engaging intensively in cotton production obtain higher grain yields than non‐cotton and marginal cotton producers. We also find evidence of regional spill‐over effects whereby commercialisation schemes induce second round investments in a particular area that provide benefits to all farmers in that region, regardless of whether they engage in that commercialisation scheme. The study suggests that the potential spill‐over benefits for food crops through participation in cash crop programs are important to consider in the development of strategies designed to intensify African food crop production.     

水利投入对国民经济增长拉动的数学模型

采用一般的Solow生产函数建立了计算水利投入对国民经济拉动作用的数学模型，应用灰色系统理论估算了资金和劳动投入的产出弹性，并通过某省一个实例进行计算，得出某省水利投入对国民经济增长拉动作用的量化数据。     

再论耕地总量动态平衡

研究目的:分析中国耕地保护政策和未来发展的极限状态,提出中国耕地保护新的思维框架,为国家制定相关政策提供参考.研究方法:反演思维法.研究结果:当中国人口达到16亿时,全国用于建设占用耕地的极限值大约在3.39×106ha～3.73×106ha左右.耕地总量到2020年将达到极限水平.到2030年人口高峰来临,尚有一定的耕地缺口.研究结论:变"耕地总量动态平衡"为"农用地总量动态平衡",变"粮食安全"为"食物安全",建立农用地总量动态平衡与食物安全监测与预警制度,从提高复种指数、增加草食养殖等途经保证食物安全.做到:总体控制,动态监测,提前预警,分区管理,统筹兼顾,逐步实施,整体发展.     

辽宁省县域经济发展的地域差异及成因

运用主成分分析及聚类分析的数理统计方法,选择10项指标,对辽宁省44个县市经济发展水平的地域差异进行了综合评价和聚类划分。主成分分析结果表明:辽宁省44个县市经济发展水平存在明显的地域差异,其影响因素可概括为工业发展及综合经济实力因素、人均经济水平因素、社会稳定因素3个层面,累积贡献率达84.8%。聚类分析的结果表明:辽宁省44个县市可划分为发达地区、较发达地区、中等发达区、初等发达区和欠发达区5种地域类型;在此基础上,分析了44个县市经济发展的地域差异原因,同时提出了协调区域经济平衡发展的相应对策。     

我国自然保护区建设刍议

作为发展中国家,建立保护区应该以改善一国、一地区的生态环境为目的,为该国、该地区经济、社会的平稳运行发展服务。保护区建设要量力而行,在保护区建设中必须强调和维护保护区的事业性质。保护区没有发展当地经济的义务。自然资源利用不管合理与否,都与保护区的事业性质相悖。保护区应实行半军事化管理。     

中国水利的现实分析与发展选择

为使人们认识到水利在国民经济中的地位与作用,文章系统的分析了建国50年来中国水利事业在艰难的条件下所取得的重大成绩,针对我国水利面临的挑战,从实际出发,探讨了水利事业发展的方略。     

建设抚—哈合作开发区的设想

抚远县和一江之隔的哈巴罗夫斯克市及其周围地区,以其优越的地缘优势、资源优势和互补性,具有发展双边(多边)经济技术合作的广阔前景。建设抚哈合作开发区,不仅有利于振兴当地经济,而且可作为参与东北亚国际分工与合作的窗口,通过外参内联,实现由边疆到内地,由双边到多边的多种形式的经贸合作,带动和促进两国内地经济的发展。     

区域矿产资源综合经济评价指标的优选途径

本文运用灰色关联分析的 3 种方法-灰色绝对关联度分析、灰色相对关联度分析和灰色综合关联分析方法,对区域矿产资源综合经济评价指标进行了优选研究,取得了满意的效果。     

Localizing Land Governance,Strengthening the State: Decentralization and Land Tenure Security in Uganda

Decentralization of land governance is expected to significantly improve land tenure security of small‐scale farmers in Africa, through ensuring better protection of their assets and reducing land‐related conflicts. This paper, however, cautions not to have too high expectations of transferring responsibilities for land administration and dispute resolution to local government bodies. Field research in Mbarara District in south‐western Uganda brings out how decentralization has limited impacts in terms of localizing land services provision. Nonetheless, local land governance has transformed in important ways, as decentralization adds to institutional multiplicity, and fuels competition among state and non‐state authorities, and about the rules they apply. Rather than strengthening local mechanisms for securing tenure, the reforms introduce new forms of tenure insecurity, fail to transform local conventions of dealing with land disputes and delegitimize local mechanisms for securing tenure. In practice, decentralization has had limited effects in securing tenure for the rural poor, yet reinforces the presence of the state at the local level in diverse ways.     

反映价格变化趋势的建设项目经济评价方法探讨──兼论对水利水电项目经济评价及其方案比较的影响

提出一种反映价格变化趋势的建设项目经济评价方法,导出在全程平均价格年变化率和分期平均价格年变化率条件下的价格与基准年固定价格的换算系数,进一步推导了各种经济评价指标的计算公式。用典型算例说明:在正常的价格变化范围内,价格变化对建设项目经济可行性评价结果和方案比较结果可能产生颠覆性的影响,因此反映价格变化趋势是必要的。该方法为在建设项目经济评价中反映价格趋势的变化提供了一种可行技术,使评价结果更符合实际。