Growing Oca, Ulluco, and Mashua in the Andes: Socioeconomic differences in cropping practices

Farmers in Andean communities depend on complex farming systems that combine native and introduced crops, production for subsistence, and production for the market. Home to the well-known potato, the Andean region is also the native place of hundreds of lesser known varieties of tubers such as oca, ulluco, and mashua. Using data from interviews and field observation in the Peruvian community of Picol, we describe the economic and social relevance of these tuber crops in the context of the local farming system. A cross-case comparison of households is used to examine the relationship between socioeconomic status and the allocation of family resources. We also explore how different agricultural practices relate to the biodiversity of indigenous tuber crops.     

Effect of the management of seed flows and mode of propagation on the genetic diversity in an Andean farming system: the case of oca (<Emphasis Type="Italic">Oxalis tuberosa</Emphasis> Mol.)

The seed system is a major component of traditional management of crop genetic diversity in developing countries. Seed flows are an important part of this system. They have been poorly studied for minor Andean crops, especially those that are propagated vegetatively. We examine the seed exchanges of Oxalis tuberosa Mol. (oca), a vegetatively propagated crop capable of sexual reproduction. We studied the seed exchanges of four rural communities in Candelaria district (Cochabamba department, Bolivia) at the international and local levels, emphasizing the spread of new sexually-produced genotypes through these exchanges. Interviews with 44 farmers generated socioeconomic, agronomic, crop diversity and seed exchange information, and data on the potential incorporation of new sexually-produced genotypes in the crop germplasm. We interviewed merchants to evaluate the input and output of genetic diversity in the communities studied. Results showed a positive effect of the farmers’ wealth on the diversity cultivated and on seed exchanges. Most seed exchanges occurred at market, creating a distinction between cash and self-consumption landraces. Cash landraces were intensively exchanged; self-consumption landraces were isolated at the farmer level and prone to genetic drift and complete loss. Merchants exported seeds of cash landraces across Bolivia and into Peru and Argentina. New sexually produced genotypes are less incorporated into cash landraces than in self-consumed landraces. However, new genotypes incorporated into cash landraces are diffused faster and better, being more intensively exchanged. We propose conservation strategies that can be applied to other vegetatively propagated and minor Andean crops.     

Tropical soils and food security: the next 50 years

An appreciation of the dynamism of the links between soil resources and society provides a platform for examining food security over the next 50 years. Interventions to reverse declining trends in food security must recognize the variable resilience and sensitivity of major tropical soil types. In most agro-ecosystems, declining crop yield is exponentially related to loss of soil quality. For the majority smallholder (subsistence) farmers, investments to reverse degradation are primarily driven by private benefit, socially or financially. "Tragedy of the commons" scenarios can be averted by pragmatic local solutions that help farmers to help themselves.     

我国彝族传统农业的生物多样性特点及其可持续发展

彝族传统农业具有环境利用、作物种植以及畜牧养殖的多样性。根据环境条件安排农作生产,利用混作、间作、套作、混牧以及农牧结合等生产技术模拟自然的生物多样性,彝族传统农业获得了良好的收益,维护了环境的生物多样性。现代农业以单一化规模生产取代传统农业的多样性,不论是“以粮为纲”还是“以钱为纲”的发展方式,带来的是生物多样性减少、水土流失加剧、灾害性气候频发以及农业生产成本增加等问题。发展适应环境特点的、适度规模化的生物多样性农业生产,利用森林植被发展林下种养殖,应用现代生物多样性技术,进一步提高农业产出和效益,将是彝族地区农业可持续发展的选择。     

Crop diversity and pest management in sustainable agriculture

Large-scale crop monocultures facilitate the proliferation and increasing prevalence of diseases and pest insects. Many studies highlight the impacts of plant diversification upon pathogens, and the population dynamics of insects and beneficial organism in agricultural ecosystems. These studies provide evidence that habitat manipulation techniques such as intercropping, relay, and rotation can significantly improve disease and pest management. This review introduces the concept of crop diversity, considers recent insights and mechanisms underlying crop diversity, and discusses its potential for improving sustainable agricultural practices. Recently, the phytobiomes resulting from increased crop diversity are increasingly recognized for their contribution to disease and pest control. Further, understanding the interactions between pathogens or pests with their host phytobiome may lead to novel options for the prevention of pests. Recent advances in the agricultural systems include:(i) a better understanding of the mechanisms of interactions between crop species and genotypes;(ii) ecological progress including a better understanding of the context-dependency of those interactions; and(iii) the role of microtopographic variation in agricultural systems for priming basal resistance to multiple pests and pathogens by intercropped crops. We also highlight recent progress in China and the potential options for habitat management and design that enhance the ecological role of biodiversity in agroecosystems.     

中国政策性农业保险参保、退保以及排斥分析--来自华中三省的证据

以往有关农业保险决策的研究较多从静态视角展开。本文在传统静态的农业保险参保决策模型之上,结合中国农业保险产品的特征,构建动态视角下的农业保险决策分析框架,阐释了农户的参保、在有参保经历之后选择退保以及对农业保险呈现需求排斥的动机。实证部分基于华中三省1051名从事农作物生产农户的调研数据,证实了获取政府补贴提高预期收益和转移农业风险的参保动机,风险赔付水平较低是农户退保的原因,以及务农风险较低或对农业保险认识不足是农业保险排斥的原因。而私人风险信息并未影响农户的参保选择,不存在明显逆向选择的参保动机。除此之外,结果还显示同群效应会显著正向增加农户的参保概率,并降低退保的概率。本文从动态视角理解农户的农业保险决策,为中国农业保险项目更好地发挥风险保障作用提供实践参考。     

Development of a web tool for action threshold evaluation in table grape pest management

Pest control is a major issue in agricultural management due to crop yield losses caused by pests. In this context, integrated pest management aims to suppress pest populations below an action threshold to minimize their impact. This paper presents the development of a web tool based on the Spanish regulations for the integrated pest management of table grapes; this provides decision support for evaluating when a particular pest action threshold has been crossed thus affecting table grape crops. The tool was built using a model-driven software development approach that enables software system generation from the problem’s knowledge model. The design of the knowledge bases which contain the system’s decision rules is also described. It is divided into knowledge bases that contain general knowledge related to the table grape crop as well as several specific knowledge bases (one per pest) containing the reasoning model that deduces the risk associated with a particular pest. The software has been designed by applying the model-driven development method thus making the system flexible, easy to evolve and adaptable whenever a new pest has to be incorporated into the software.     

钾肥对农作物品质的影响

 钾是影响作物品质的“品质因子”。在氮、磷充足的基础上施用钾肥,能提高农作物品质。钾能促进光合作用、碳水化合物的代谢及运输、蛋白质的合成。根据前人的资料和研究,对钾如何影响谷类作物,块根、块茎作物、蔬菜及烤烟品质的问题作了简要评述。     

耕作方式对主要粮食作物影响的研究综述

笔者通过对相关资料的整理与分析,阐述了常见不同耕作方式对主要粮食作物根系特性、光合效应、品质指标及产量的影响,分析了未来农业生产中进一步加强对耕作方式研究的必要性和重要性,并指出今后农业生产中应在结合中国国情的基础上注重根据区域生态环境、土壤属性、作物种类及茬口类型选择适宜的耕作方式,试图为中国农业生产中耕作方式更加合理的选择与运用及作物产量的提高和耕地的可持续利用提供科学依据和理论帮助。     

农户兼业、生产环节外包与农业种植结构“趋粮化”

粮食安全是国家安全的重要基础。随着农户兼业化趋势的加强,农村务农劳动力不断流失,生产外包服务市场不断发展,在这个大背景下,农户兼业和生产环节外包对农业种植结构"趋粮化"的影响引发社会各界关注。本文基于全国9省调查数据,通过构建中介效应检验模型分析三者之间的作用逻辑及因果关系。研究结果表明:农户兼业在总体上促进种植结构"趋粮化",生产环节外包特征变量在农户兼业影响种植结构调整的过程中发挥部分中介效应,此外,被访者性别、年龄、家庭总收入、村庄地形和交通设施对农户粮食种植结构调整也存在显著影响。据此,本文认为,为引导农户种植结构"趋粮化",保障国家粮食安全,要合理引导农村劳动力外流,统筹城乡发展;推动农业生产环节外包市场的发育与完善,提高农业生产过程中的外包服务率;同时,制定合理的价格支持政策,保障农户种粮积极性。     

Interpretation of Climate Change and Agricultural Adaptations by Local Household Farmers: a Case Study at Bin County,Northeast China

Although climate change impacts and agricultural adaptations have been studied extensively, how smallholder farmers perceive climate change and adapt their agricultural activities is poorly understood. Survey-based data (presents farmers' personal perceptions and adaptations to climate change) associated with external biophysical-socioeconomic data (presents real-world climate change) were used to develop a farmer-centered framework to explore climate change impacts and agricultural adaptations at a local level. A case study at Bin County (1980s–2010s), Northeast China, suggested that increased annual average temperature (0.6°C per decade) and decreased annual precipitation (46 mm per decade, both from meteorological datasets) were correctly perceived by 76 and 66.9%, respectively, of farmers from the survey, and that a longer growing season was confirmed by 70% of them. These reasonably correct perceptions enabled local farmers to make appropriate adaptations to cope with climate change: Longer season alternative varieties were found for maize and rice, which led to a significant yield increase for both crops. The longer season also affected crop choice: More farmers selected maize instead of soybean, as implicated from survey results by a large increase in the maize growing area. Comparing warming-related factors, we found that precipitation and agricultural disasters were the least likely causes for farmers' agricultural decisions. As a result, crop and variety selection, rather than disaster prevention and infrastructure improvement, was the most common ways for farmers to adapt to the notable warming trend in the study region.     

Transitions to agroecological farming systems in the Mississippi River Basin: toward an integrated socioecological analysis

Industrial agriculture has extensive environmental and social costs, and efforts to create alternative farming systems are widespread if not yet widely successful. This study explored how a set of grain farmers and rotational graziers in Iowa transitioned to agroecological management practices. Our focus on the resources and strategies that farmers mobilized to develop opportunities for, and overcome barriers to, transitioning to alternative practices allows us to go beyond the existing literature focused on why farmers transition. We attend to both the ecological and socioeconomic context of innovation by comparing processes of technical change in two contrasting regions of Iowa. Farmers cultivated farm-level biodiversity and enterprise diversity, developed new cognitive and psychological competencies, and overcame barriers to innovation by developing external network linkages with peers, knowledge organizations, and federal policies. Our research provides insights into how biophysical, cognitive, structural and market considerations can be integrated into research efforts that aim to make sense of innovation toward sustainable agriculture.     

生物多样性及其在农田作物生产中的意义和作用

从生物多样性这一现代研究课题了出发，论述了作物在多样性。作物与杂草关系的意义。     

茎瘤芥(榨菜)种质资源研究进展

茎瘤芥(榨菜)作为我国特有的农业资源,仅分布于中国长江流域,其加工产品"涪陵榨菜"蜚声海内外,与欧洲甜酸甘蓝、日本腌菜并称世界三大名腌菜。文章从起源、分类及分布、核型与花粉形态、生理特性、蛋白质水平及遗传与育种研究等方面综述了茎瘤芥种质资源的研究进展,并展望其研究前景。     

The Effect of Crop Rotation on Soil Nematode Community Composition in a Greenhouse

[Objective] The aim was to identify changes in a nematode community in response to crop rotation and to determine the appropriate catch crop for a greenhouse. [Method] The experiment was carried out in a typical 6-year-old greenhouse,in which cucumber crops were cultivated twice each year(in spring and autumn),and catch crops were planted in summer. The total number of nematodes was counted and nematode community indices were calculated after collecting soil samples in different stages. [Result] Total nematode abundance was decreased in the soils of catch crop in contrast with former crops(cucumber crops). The abundance of the nematode community was reduced in the treatment of crop rotation compared to the soils of catch crop. In addition, the number of nematode taxa was significantly reduced by the treatment of crown daisy compared to the treatments of following crops. Crop rotation regulated the functional composition of the nematode community by increasing the omnivores-predators functional group and decreasing the relative abundance of root herbivores. [Conclusion] These results indicate that crop rotation affects the nematode community in abundance, diversity and functional composition of the nematode community and crown daisy can be served as the most appropriate catch crop in the greenhouse.     

农业生物多样性防控作物病虫害的研究进展

农业生物多样性对维系农业系统的生态平衡和保障农业可持续发展起到重要的作用,为防治农作物的病虫害以提高作物产量,该文综述了农业种质资源多样性、农业物质多样性和农业景观多样性对农作物病虫害防控的研究进展,提出在现代农业防治中应尽量减少高毒农药的使用,利用农业生态中的生物多样性来持续控制农业病虫害发生的思路,以充分利用农业生物多样性在作物病虫害防控方面的作用。     

贫困与作物多样性:基于中国北方偏远地区农户作物种植研究(英文)

在中国北方偏远地区农民种植着多类小杂粮作物,当地有着丰富的作物遗传资源,利用农户调查数据,建立计量经济学模型分析农户多作物种植以及贫富农户作物种植的差异发现,贫困农户更倾向于多样性。建议政府和科研部门如果能够加大基础设施建设和小作物的科研投入和技术推广力度,改变小杂粮被忽视的境况,既有利于这些地区的减贫工作,使当地贫困人口共享经济和社会发展的成果,又有利于保护当地的作物遗传资源,实现农业生产的可持续发展。     

农户土地利用行为的区域差异分析——以湖北省平原和丘陵地区为例

基于农户调查数据和统计资料,对湖北省江汉平原地区和湖北省咸宁市丘陵地区的农户土地利用行为进行比较分析。结果表明,平原地区农地利用率和农业劳动力产出水平均高于丘陵地区,同时平原地区农地利用的机械化程度更高,农户土地利用规模更大。但平原地区农作物种类更单一,近30年来粮食作物播种面积减少的比率也更大,且平原地区农地利用的物质投入成本和劳动力机会成本也大于丘陵地区。     

农村土地雇佣生产合约的委托-代理模型分析

家庭联产承包责任制早期,中国农村土地普遍小规模耕种,小农经营色彩浓厚.在中央政府允许和鼓励土地承包经营权流转的政策背景下,农地流转的集中化和农地经营的规模化趋势逐步明显,大规模土地持有者以各种合约形式雇佣农村无地劳动者,农业雇佣生产在各地陆续展开.本文分析了新时期土地规模化流转背景下,农业雇佣生产、生产合约选择以及雇佣生产的实践形式等问题     

What would farmers do? Adaptation intentions under a Corn Belt climate change scenario

This paper examines farmer intentions to adapt to global climate change by analyzing responses to a climate change scenario presented in a survey given to large-scale farmers (n = 4778) across the US Corn Belt in 2012. Adaptive strategies are evaluated in the context of decision making and farmers’ intention to increase their use of three production practices promoted across the Corn Belt: no-till farming, cover crops, and tile drainage. This paper also provides a novel conceptual framework that bridges a typology of adaptation with concepts that help predict intentionality in behavior change models. This conceptual framework was developed to facilitate examination of adaptive decision making in the context of agriculture. This research effort examines key factors that influence farmers’ intentions to increase their use of the practices evaluated given a climate change scenario. Twenty-two covariates are examined across three models developed for no-till farming, cover crops, and tile drainage. Findings highlight that farmers who believed they should adjust their practices to protect their farm from the negative impacts of increased weather variability were more likely to indicate that they would increase their use of each of the practices in response to climate change. Additionally, visiting with other farmers to observe their practices was positively associated with farmers’ intentions to increase their use of the adaptive strategies examined. Farmers who were currently using no-till farming, cover crops, and tile drainage were also more likely to plan to increase their use of these practices in response to increased weather variability associated with climate change. However, farmers who reported high levels of confidence in their current practices were less likely to plan on changing their use of these practices in response to climatic changes.