Adopters,testers or pseudo-adopters? Dynamics of the use of improved tree fallows by farmers in western Kenya

Although there has been increasing research on the adoption of agroforestry technologies over the last decade, few such studies have assessed uptake over a long period and many are based on a single snapshot in time. Furthermore, most of these studies have mainly looked at non-adopters and adopters: only recently have social scientists considered testers. A further category of users neglected in adoption studies has been re-adopters of technologies. Studying this group provides an interesting and more nuanced understanding of adoption and re-adoption. Methodologically, most adoption studies use quantitative methods and fail to link their findings to wider socio-economic, political and institutional settings. This paper presents a study of the dynamics of improved tree fallow use by farmers in Siaya and Vihiga districts of western Kenya over a period of eight years. It uses both qualitative and quantitative data to critically discuss the motivations of adopters, testers/rejecters and re-adopters. The results show that the process of adoption is highly dynamic and variable with farmers planting improved fallows and discontinuing or re-adopting them due to a whole range of factors, of which soil fertility improvement is just one. These factors included incentives from projects, the tying of adoption to credit programmes, prestige, participation in seminars/tours and the availability of a seed market from projects promoting improved fallows. Farmers planting improved fallows for such reasons may be termed ‘pseudo-adopters’. There were significant differences in adoption between the two districts, with more farmers in Siaya planting improved fallows than in Vihiga. A majority of farmers in Vihiga (53%) who were given seed never planted improved fallows, even though they had been exposed to the technology. Some 40% of farmers in Siaya and 38% in Vihiga planted improved fallows but later rejected them. This has some important implications for research and development. For improved fallow technologies to be attractive to farmers, they must provide other tangible economic benefits besides soil fertility improvement. This presents a challenge to researchers who must better attune themselves to the needs and demands of farmers if they wish to see their research findings widely adopted.     

自压式树状管网的两级优化设计模型与神经优化设计

建立了自压式树状管网两级优化设计模型，并用人工神经网络法实现树状管网非线性规划模型的快速求解。采用的人工神经网络技术的两级优化设计模型在适用范围、求解速度和获得最优解能力上，均优于单一的非线性规划模型和线性规划模型，是实现树状管网全局优化设计的一条新途径。     

大坝安全风险评估初探

根据风险理论在其它领域的应用实践，以及大坝安全风险管理在国外的应用经验，将大坝安全风险评估的原理、实施步骤等进行了阐述，探讨了大坝风险因素、失事树分析法及事件概率计算方法等诸多关键问题，并通过算例对文中所探讨的问题进行了较为明确的应用与说明。     

联合收割机液压系统故障树分析

故障树分析法(FTA)是一种将系统故障形成的原因由总体到部分按倒立树形状逐级细化的分析方法,是一种对系统设计、故障分析和排除非常有效的方法。为此,应用故障树分析方法对联合收割机液压系统进行了分析,根据液压系统结构以及组件与系统之间的逻辑关系,绘制了系统的故障树,并通过结构函数表示了各种因素对系统状态的影响。     

大数据时代山东农业病虫害监测预警体系建设

在大数据时代,海量的数据资源是推动经济发展和社会进步的基石,丰富、透明、完善的农业大数据资源是加快农业信息化建设步伐的前提,先进、有序、完备的农业病虫害监测预警体系是服务绿色农业发展的支撑。该研究试图在研究国内外农业病虫害监测预警体系的基础上,在农业专家的指导下,进行大数据时代农业病虫害监测预警体系构建。山东农业病虫害监测预警体系的建设应主动适应大数据时代的发展需求,分步构建病虫害监测预警体系,分层划分病虫害数据中心工作,合理布局病虫害数据采集站点,科学制定病虫害监测预警任务,共建共享病虫害监测数据信息,有效加强病虫害联合监测预警,努力研发病虫害智能识别终端,为发展现代高效农业提供坚实的保障。     

勐满分公司气刺微割试验总结

4年的气刺微割试验结果表明，气刺微割能明显提高产量和割胶劳动生产率，降低干胶含量，而死皮等副作用不明显。采用气刺微割后，必须控制增产幅度，以保持胶树的长期高产稳产。     

Can incidental sighting data be used to elucidate habitat preferences and areas of suitable habitat for a cryptic species?

The involvement of communities in ecological studies has been shown to augment conservation efforts, especially for cryptic species. However, there is a lack of studies addressing the utility of incidental sighting records from community members in gaining knowledge on habitat preferences and distribution of suitable habitat for these organisms. This study compares preferences of the Lumholtz's tree kangaroo (Dendrolagus lumholtzi ; LTK), a cryptic rainforest folivore in northeastern Australia, for various habitat and climatic variables derived from data collected during scientific projects to those derived from incidental sighting records using ArcGIS and Maxent. Incidental sighting records suggest that the species uses a wider range of altitudes, annual rainfalls, annual mean temperatures and vegetation types than predicted by scientific studies. Incidental records also show that the species can persist in areas of lower rainfall during the wettest month and lower minimum temperature during the coldest month. Both data place the species within a comparable range of rainfalls during the driest month, maximum temperatures of the warmest month and soil types. When using identified preferences to assess the extent and distribution of suitable habitat, incidental records predicted more areas of suitable habitat than scientific records with an overlap of up to 91% between them. The present study proves that incidental sighting records can be a valuable part of the study of cryptic species and should be considered complementarily alongside scientific studies to obtain comprehensive ecological information of a species that can assist in its conservation.     

长春市主要绿化树种适应低温冻害能力的调查与分析

以长春市部分绿地的主要园林绿化树种为对象,对其适应低温冻害的能力进行了调查与分析,结果表明:在2009～2010年冬春季节持续低温作用下,12种外来树种中未遭受冻害的有青杄等7种,占58.3%;油松、丹东桧柏、大径级垂榆、京桃、刺槐普遍遭受冻害,都有死亡植株发生,其中大径级垂榆冻死率高达63.6%。低温累积效应是导致树木遭受冻害的主要因素,种间的遗传差异亦是因素之一。乡土野生树种无冻害相发生。     

中国渔业“大国效应”特征、战略选择及其政策建议

中国是渔业大国,但与其他渔业大国相比,存在显著不同的发展环境、条件和特点。本文在以往讨论我国渔业大国的基础上,综合学者的研究成果,以"大国效应"为视点,讨论我国渔业大国现象特征、研究其规律;归纳分析了秘鲁、日本和前苏联等渔业大国的"优势陷阱";对我国渔业战略发展提出积极运用渔业大国效应、保持领先发展战略的政策建议。