Estimating Bird Damage to Rice in Africa: Evidence from the Senegal River Valley

Granivorous birds, mainly the Red‐billed Quelea, have subsisted on cereal crops in Africa for centuries and have caused substantial damage. There is, however, limited recent evidence on their impact. We propose an indirect method to estimate bird‐inflicted crop losses by fitting a production function with a damage abatement component and pest intensity slope dummies on a panel database of rice farmers in the Senegal River Valley. This allows us to estimate both bird damage and marginal productivity of bird control at different levels of bird pressure. Annual bird damage is found to average around 13.2% of the potential rice production during the wet seasons of 2003–2007, which translates into an average annual economic loss of 4.7 billion FCFA (€7.1 million). Our results are consistent with farmers’ perceived bird‐inflicted crop losses, averaging 15.2%. More alarmingly, we observe declining marginal productivities of bird control under increasing bird pressure. Farmers indicate that at high bird pressure, the efficacy of traditional bird scaring methods is inadequate, which suggests that predictive (monitoring), preventive (population control) and protective (insurance) measures against massive invasions are more urgent than improving the average efficacy of curative measures (pest control). These findings are especially relevant to farmers and policy‐makers who are currently struggling to implement an ambitious food self‐sufficiency programme in Senegal.     

PLANT PESTICIDE ECONOMICS WITH SPECIAL REFERENCE TO COTTON INSECTICIDES

The energy crisis and the current world food situation have both drawn attention to the importance of off-farm inputs in high-technology agricultural systems. Plant pesticides are one of the most important of these off-farm inputs. The correct use of chemical pesticides requires a high level of managerial competence since the issues involved are extremely complex. The development of an integrated approach to the management of plant pests offers an alternative to the increasingly expensive chemical control techniques. Cotton production illustrates both the complexities of the management involved in plant pest control and the feasibility of developing integrated control strategies. Plant pesticides, especially insecticides, also create externalities. The policy issues surrounding the use of cotton insecticides demonstrates the need for careful analysis before political action is taken. A feasible package of policy measures for the control of the use of insecticides in Australian cotton-growing areas is suggested.     

The Dynamics of Pest Resistance Management: The Case of Refuge Fields for Bt Crops

We examine the optimal time‐variant refuge policy to manage pest resistance to Bacillus thuringiensis (Bt) crops in a finite, discrete‐time horizon model. We identify analytically the intertemporal effects of refuge fields on the pest population and its susceptibility. The shape of the optimal refuge policy and whether or not pest susceptibility should be exhausted completely at the end of the time horizon depend crucially on the values of a cost premium of Bt seeds and the fitness cost of resistance (over mortality of resistant pests) and are addressed via numerical simulations. We demonstrate the importance of modeling the dynamics of the biological system accurately, of defining a diploid (and not haploid) biological model, and of using a discrete‐time (rather than continuous‐time) framework.     

Biosecurity in agriculture: an economic analysis of coexistence of professional and hobby production*

One component of biosecurity is protection against invasive alien species, which are one of the most important threats worldwide to native biodiversity and economic profitability in various sectors, including agriculture. However, agricultural producers are not homogeneous. They may have different objectives and priorities, use different technologies, and occupy heterogeneous parcels of land. If the producers differ in terms of their attitude towards invasive pests and the damages they cause, there are probably external effects in the form of pest spread impacts and subsequent damages caused. We study such impacts in the case of two producer types: profit‐seeking professional producers and utility‐seeking hobby producers. We show that the hobby producer, having first set a breeding ground for the pest, under‐invests in pest control. We also discuss potential policy instruments to correct this market failure and highlight the importance of considering different stakeholders and their heterogeneous incentives when designing policies to control invasive alien species.     

Primary and secondary pest management in agriculture: balancing pesticides and natural enemies in potato production

Natural enemies (NEs) provide an important ecosystem service by preying on variety of pests in agricultural crop production systems. Current management practices of both primary and secondary pests in agricultural production principally rely on the use of pesticides with associated negative social and environmental consequences/externalities. Excessive use of pesticides against primary pets can remove NEs from the agro‐ecosystem and amplify susceptibility of the system to outbreaks of secondary pests. The combined effect of NEs on primary and secondary pests has received limited attention. This study uses an intraseasonal bioeconomic model to explicitly take into account biological interactions among primary pests, secondary pests, and NEs assuming decision makers’ profit maximizing behavior. The model explicitly captures the opportunity cost of injury to NE in terms of both primary and secondary pest suppression by NE. The results show that in the context of the green peach aphid (primary pest) and two‐spotted spider mite (secondary pest) in potato production, inclusion of NE into pest mitigation strategy can increase returns by 2%.     

Specification and Estimation of Production Functions Involving Damage Control Inputs: A Two-Stage, Semiparametric Approach

Productivity assessment of damage control inputs (such as pesticides) is complicated because their effect depends on the exposure to damage agents (such as pests). We discuss some open specification and estimation issues. The contribution is threefold. First, we elaborate the separability conditions for the damage control function and production function. Second, we employ a two-stage semiparametric technique to combine attractive features of both nonparametric and parametric approaches. Third, we model the interaction between pest exposure and damage control inputs by using slope dummies. An application to productivity analysis of small scale Bt cotton production in China illustrates the approach.     

南水北调工程丹江口水库消落区保护与利用管理研究

阐述了南水北调工程丹江口水库消落区保护与利用管理的目的和意义,分析了丹江口水库初期工程消落区保护与利用管理的现状,并在此基础上对大坝加高后水库消落区保护与利用管理的体制机制、模式途径等进行了研究,提出了尽快制定消落区保护与利用管理的政策法规,开展消落区保护与利用规划,以及开展消落区治理和保护、植物培育、水环境保护、资源配置等科学研究的对策建议。     

Context sensitive policy instruments: A multi-criteria decision analysis for safeguarding forest habitats in Southwestern Finland

Environmental and conservation decisions are often complex, which results in complexity also in policy assessments. Conservation decisions have implications for different stakeholders and typically draw on multidisciplinary knowledge bases, incorporating natural, physical and social sciences, politics and ethics. Multi-Criteria Decision Analysis (MCDA) is a potentially important tool for supporting conservation policy decisions. This article reports a spatially referenced MCDA of policy instrument scenarios for conserving forest biodiversity in Southwestern Finland. The effects of the realistic policy instruments designed in dialogue with stakeholders included voluntary permanent conservation, enforced spatially concentrated permanent conservation, voluntary permanent conservation with active nature management, and voluntary temporary conservation. These instruments were compared by combining forest-owner survey, MCDA and ex ante impact evaluation. The main objective was to find the forest biodiversity conservation instrument that would produce the highest total benefit. The effects of the different instruments were evaluated with ecological, economic, social, and institutional criteria after a 20-year time period. The results showed minor differences between the instruments, with voluntary permanent and voluntary temporary conservation producing the largest total benefit. Despite the small differences, the analysis was robust in showing that voluntary instruments were more favourable than enforced permanent conservation.     

发展权受限角度下永久基本农田划定中补偿价格的测算 ——以重庆市为例

国家对永久基本农田建立了严格的保护制度,各地也尝试构建耕地保护的补偿机制,但补偿价格的测算目前还没有比较科学的方法,多是结合当地财政状况和经验值进行估算.本文从土地发展权损失的角度,通过量化发展权受限的损失对永久基本农田保护补偿价格进行测算,为建立基本农田保护激励机制提供依据和支撑.     

新冠肺炎疫情对我国粮食安全的影响分析及稳定产量的建议

稳定粮食安全根基是应对各类黑天鹅、灰犀牛事件的有力保障。疫情期间,充足的粮食供给再次发挥了安天下、稳民心的作用。从目前调查的情况来看,疫情对粮食生产经营的影响是暂时的、局部的、有限的,疫情持续也带来农资价格上涨、物资到位迟缓等问题。但种粮效益低、农业气象偏差、传统病虫害与输入性虫害叠加、国际经贸形势日趋复杂等挑战交织,是确保全年粮食产量、供应稳定的主要挑战。要高度重视抗疫战线拉长带来的负面影响,积极疏通农资供应渠道、有序组织返田返工,更要稳住政策支持,完善设施装备配套,强化技术支撑,做好防灾减灾。     

储粮害虫新型熏蒸技术应用与研究

本文通过不同熏蒸方式对储粮害虫的抑杀效果的研究分析,为选取合适的熏蒸方式抑杀储粮害虫提供参考,从而达到粮食储藏过程中的虫害控制,减少因虫害侵蚀造成的粮食损失.     

Sequester or substitute—Consequences of increased production of wood based energy on the carbon balance in Finland

Forests play an important role in mitigating climate change. Forests can sequester carbon from the atmosphere and provide biomass, which can be used to substitute for fossil fuels or energy-intensive materials. International climate policies favor the use of wood to substitute for fossil fuels rather than using forests as carbon sink. We examine the trade off between sequestering carbon in forests and substituting wood for fossil fuels in Finland. For Finland to meet its EU targets for the use of renewable energy by 2020, a considerable increase in the use of wood for energy is necessary. We compare scenarios in which the wood energy targets are fully or partially met to a reference case where policies favoring wood based energy production are removed. Three models are used to project fossil fuel substitution and changes in forest carbon sinks in the scenarios through 2035.Finnish forests are a growing carbon sink in all scenarios. However, net greenhouse gas (GHG) emissions will be higher in the medium term if Finland achieves its current wood energy targets than if the use of energy wood stagnates or decreases. The volume of GHG emissions avoided by replacing coal, peat and fossil diesel with wood is outweighed by the loss in carbon sequestered in forests due to increased biomass removals. Therefore, the current wood energy targets seem excessive and harmful to the climate. In particular, biodiesel production has a significant, negative impact on net emissions in the period considered. However, we did not consider risks such as forest fires, wind damage and diseases, which might weaken the sequestration policy. The potential albedo impacts of harvesting the forests were not considered either.     

基于河南生态旅游现状调查分析的农村生态旅游法律保护研究

[目的]通过分析河南生态旅游现状并在农村生态旅游法律保护方面提出建议,以期为河南生态旅游产业可持续发展提供借鉴。[方法]文章通过文献查阅法对农村生态旅游相关概念进行总结和梳理,分析河南生态旅游发展现状、游发展中存在的问题,由此立足法律保护提出建议。[结果]发现河南省许多农村生态旅游景区存在生态旅游开发规划尚缺乏科学性、管理水平低下、农村生态旅游意识较为薄弱等问题,从法律保护角度提出着力推进农村生态旅游法律体系建设、强化当地居民及游客生态保护法制观念、建立生态旅游法律保护的监督机制等建议。[结论]着力推进农村生态旅游法律保护体系建设,是河南农村生态旅游发展的重要途径。     

To populate or preserve? Evolving political-demographic and environmental paradigms in Israeli land-use policy

There has been a recent proliferation of national land-use policies that emphasize protecting open space and ecosystem integrity. However, countries grappling with internal political conflict, or that are engaged in military conflicts with neighboring countries, have priorities that focus on control of land in areas where state sovereignty is perceived to be threatened. These two concerns, political-demographic control and environmental protection, create very different paradigms for how to think about open space policy. The objective of this paper is to consider the impact of competing paradigms in land-use policy formulation and implementation—one that encourages sprawl and the other that encourages compact development and the preservation of open space. We use Israel as a case study where both political demography and environmental land-use paradigms are currently influencing policy and planning. We explore the historical evolution of both land-use paradigms and consider how they are currently competing in the formulation and execution of land-use policy decisions. We consider how these distinct priorities are playing out in current discourse and policy implementation, and characterize the past, current and prospective future physical outcomes of policies on the landscape. Our goal is to alert policy makers and land-use scholars of the subtle and contradictory influence of political-demographic land-use priorities with regard to their potential impact on the successful implementation of environmental policies. The Israeli case study is indicative of a diversity of countries that have a history of political-demographic land-use policies, but have also begun to adopt environmentally motivated policies.     

精益管理在大米加工厂虫害防治中的应用实践

为探讨精益管理方法在控制大米加工厂害虫滋生中的应用价值.采用精益管理的方法与工具分析某大米加工厂原有的害虫防控工作流程中存在的问题,针对性地进行优化和持续改进.比较实施精益管理前后大米加工厂因生虫导致的退货和滞销生虫数量的变化.结果表明:实施精益管理后,大米加工厂生虫退货数量由原来的411.9 t/a,显著降低到145...     

大连与东北经济区共同发展对策探讨

区域经济共同发展是我国的基本国策,也是加快构建和谐社会的必然要求;从分析区域经济一体化发展趋势入手,在分析东北经济区经济发展现状及存在问题的基础上,明确了大连在东北经济区中发挥经济领长、产业引领、体制示范、区域联结、综合服务的地位和作用;明确了东北经济区共同发展的战略思想、基本原则,提出了市场一体化、产业一体化、信息一体化、交通一体化等4个方面的战略任务,从解放思想、建立协调互动机制、摘好区域分工、建立健全政策法规体系、推进国际化等方面提出东北经济区共同发展的相关政策措施.     

基于物-场模型的基本农田划定合理性评价

[目的]永久性基本农田划定是稳定耕地面积,控制建设用地无限制扩张的重要手段。[方法]文章以物-场模型为基础,将基本农田划定产生的影响理解为基本农田保护区划定、基本农田功能要素以及基本农田保护区影响场三要素有机组合所形成的系统效应或功能。并借鉴空间相互作用的引力模型,构建了包含基本农田划定适宜性、基本农田功能要素协调性以及距离系数的基本农田划定合理性评价模型。[结果]选取泽州县新一轮基本农田保护区为研究区域,对其保护区划定合理性进行评价,并依据评价结果划分为高度合理区、中度合理区、一般合理区、较不合理区和不合理区,并提出相应管理措施。通过定量化分析,泽州县基本农田划定合理区域占总面积的82%,保护区划定较为合理。[结论]该研究结果可为管理决策部门进行基本农田保护区空间布局合理性评价、为合理安排基本农田生产、生态等功能、基本农田布局调整提供依据。     

3s技术在基本农田调查清理中的应用——以重庆市巫山县为例

划定永久基本农田是实现耕地保护目标的重要手段,为做好永久基本农田调整完善工作需要对基本农田现状进行调查清理,以重庆市巫山县为例,提供基于3S技术支撑的技术方法和工作思路。结果表明,以3S技术手段进行基本农田现状调查清理,能快速、准确查清基本农田现状数据中不符合基本农田划定要求的地类,能满足基本农田动态监测的需要,将更好地在基本农田划定与保护中得以应用。     

Protectionism, Trade, and Measures of Damage from Exotic Species Introductions

Unintentional introductions of nonindigenous plants, animals, and microbes cause significant ecological and agricultural crop damage worldwide. Trade in both manufactured and agricultural goods is a primary vector for such introductions. Fusing simple models of trade and biological introductions, we explore the links between trade, protectionism, and damage arising from exotic species introductions. We show that it is possible for freer trade to reduce damage arising from exotic species invasions. We also show how current measures of damage—heavily weighted toward agricultural damage—serve as misleading indicators of how restrictions to trade affect total losses arising from exotic species introductions.     

粮食生产、生态保护与宏观调控政策

[目的]长期以来,粮食生产与生态保护一直是一对矛盾综合体,为了实现粮食安全目标,人们往往忽略对于生态的保护,通过对二者之间的相互影响机理的分析,提出更好的宏观调控政策。[方法]采用因果分析法对粮食安全框架下的粮食生产和生态保护的演进关系、影响形式和内容进行了研究,最终给出了二者协调发展的粮食宏观调控政策设计对策。[结果]首先,不合理粮食生产活动对生态环境造成的严重破坏,主要体现在水土流失、水资源浪费、化学物质的残留和生态环境的污染;其次,被破坏的生态环境反过来影响了粮食生产的数量和质量,进而对粮食安全产生了威胁。[结论]为了保证粮食安全的目标,长期牺牲生态环境的做法已经带来了严重的后果,这种后果不仅仅表现为当前的生态失衡,更严重威胁了未来的粮食安全。因此,要充分发挥粮食宏观调控政策的作用,加强生态功能设计,具体可从建立农业自然资源保护和有效利用的制度机制、加强政府生态农业的主导型地位及投入水平、以技术进步支撑保护农业生态和粮食安全和以法律手段规范保证相应措施的顺利实施4个方面进行设计和完善。