水稻栽培适宜品种选择的知识模型

在阅读大量献资料及咨询农学专家的基础上，运用知识工程和系统建模方法，总结、归纳和提炼水稻品种选择与品种类型、生态环境和农作制度之间的动态关系，定量计算了水稻品种特征值与环境因子和生产需求之间的符合度，建立了适宜品种选择的量化知识模型。该模型可用于定量设计不同环境和生产条件下水稻种植的适宜品种。利用沈阳、南京、常德、昆明和广州5个代表性生态点的常年逐日气象资料、当地的生产条件以及24个不同品种资料，对品种选择知识模型进行了实例分析。结果表明模型预测结果与当地实际情况基本吻合。从而证明知识模型能有效地依据决策点的自然资源条件．对决策点适宜种植品种的选择具有较好的解释性和可靠性。     

集约持续农作制度的理论探讨

对集约持续农作制度在中国农业发展中的作用进行了理论和实证分析。作者指出,农作制度的理论和方法在农业系统的管理中具有非常重要的作用。农作制度是人类利用农业系统实现生产目的的桥梁,在农作制度的理论和方法方面,偏隍需要更多高水平的综合研究,以促进持续、高产的农业系统发展,对生态经济位的概念进行了阐释。     

Farming systems approaches to international technical cooperation in agriculture and rural life

A farming systems approach to development has meant many things over the past 15 years, depending on its institutional and ecological setting, its target populations, and the goals motivating its implementation. Despite the diversity of approaches, and the sometimes rancorous discussion over which was best and why, the approach is now recognized in many places as the only one that can identify and respond to the needs of limited resource farm families, especially those in marginal ecosystems. Involving an iterative process of diagnosis, design, testing and extension, the farming system approach to date has done more to change research objectives at national and international institutions than to change actual farmer practices. By legitimizing what limited resource farmers do and why they do it, a farming systems approach lends itself to policy analysis as well. Recent research in farming systems suggests greater attention should be payed to exogenous variables, including policy and infrastructure, as well as to development of technology that really responds to the felt needs of limited resource farmers in improving their level of living.     

湖南省不同种植制度农田土壤肥力长期演变特征北大核心CSCD

明确不同种植制度农田肥力长期演变特征可为选择合适种植制度以提升耕地质量提供参考依据。以湖南省12个国家和省级农田长期定位试验点的种植制度试验为研究对象,选择当地习惯施肥条件下的水稻—水稻—黑麦草(RRR)、水稻—水稻—紫云英(RRC)、水稻—水稻—大麦(RRB)、水稻—水稻—冬闲(RRW)和水稻—水稻—油菜(RRO)5种双季稻模式,烤烟—水稻(RT)、水稻—冬闲(RW)、水稻—油菜(RO)和水稻—绿肥(RG)4种一季稻模式,棉花—油菜(CR)、大豆—红薯(SS)和玉米—萝卜(MR)3种旱作模式,研究其土壤基础肥力指标和综合肥力的演变趋势。结果表明,双季稻模式有机质含量高于旱作模式,长期习惯性施肥条件下,除RRO、RT和RW有机质含量下降外,其余均有上升。RRW、RRO、RT和RW全氮含量相对较高但均有下降,其余则均有增加。RRO和RG碱解氮含量下降明显,而旱作模式均呈增加趋势。RRO和RRW速效磷含量下降明显,而旱作模式年均增加约1.23~4.76 mg/kg。双季稻模式速效钾含量均有下降,而一季稻和旱作模式除RT和MR增加外呈下降趋势或无明显变化。双季稻模式综合肥力下降,而一季稻和旱作模式均有上升。研究表明,湖南省不同种植制度农田肥力变化差异较大,双季稻模式应控氮重钾,一季稻模式应减施氮磷,旱作模式应培肥地力和控施磷肥。     

Comment on "Disentangling the drivers of β diversity along latitudinal and elevational gradients"

Kraft et al. (Report, 23 September 2011, p. 1755) analyzed two data sets and concluded that "there is no need to invoke differences in the mechanisms of community assembly in temperate versus tropical systems to explain these global-scale patterns of β diversity." We show that their conclusion is based on inappropriate data and inadequate methods of analysis.     

风险条件下农户种植制度选择与调整——以北京市蔬菜种植户为例

为深入研究风险条件下的农户种植制度的选择与调整行为,揭示农户多元化种植制度调整的合理性,从而为指导农户进行种植制度的选择与调整提供依据.利用对北京市蔬菜种植户抽样调查所获得的截面数据,采用MOTAD模型实证分析了蔬菜种植户的生产经营状况及其在风险条件下种植制度选择行为.结果表明:北京市蔬菜种植户在生产中主要面临价格风险,而且在风险条件下,农户会对其蔬菜种植结构进行调整.本研究结合效用最大化条件,测算出了适合于当地农户的蔬菜种植制度,即农户在效用最大化的条件下可以利用0.41 hm2的土地进行多元化的蔬菜种植,并达到预期收益.根据实地调研显示,北京市蔬菜种植户户均耕地面积达0.74 hm2,研究结果能够为当地的生产经营提供借鉴.     

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.     

AFHVS 2016 presidential address: Decoding diversity in the food system: wheat and bread in North America

Diversity is important for the resilience of food systems, as well as for its own sake. Just how diverse are the systems that produce our food? I explore this question with a focus on wheat and bread and North America, and even more specifically in baking, milling and farming. Although the opacity of food and agricultural systems makes definitive answers difficult, these segments appear to be increasingly uniform with respect to ownership, geography, varieties and genes. There are also important countertrends, and while efforts to resist uniformity are currently small, they are making some progress in maintaining or even increasing diversity in some areas.     

节水农作制度综合效益评价的研究

从自然生态、经济、社会三个方面探讨节水农作制度形成的影响因素,将所涵盖的因素又分别细分为几类,从理化机制及国内外实践经验出发,科学分析了各种因素对节水农作制度形成与发展的制约形式,建立中国旱作地区节水农作制度形成机制的基本理论框架,并提出节水农作制度综合效益评价的构想.     

Enabling food sovereignty and a prosperous future for peasants by understanding the factors that marginalise peasants and lead to poverty and hunger

Dominant development discourse and policy are based on crucial misconceptions about peasants and their livelihoods. Peasants are viewed as inherently poor and hungry and their farming systems are considered inefficient, of low productivity, and sometimes even environmentally degrading. Consequently, dominant development policies have tried to transform peasants into something else: industrialised commercial farmers, wage labourers, urban workers, etc. This article seeks to deconstruct three key misconceptions about peasants by explaining how and why marginalised peasants around the world face poverty and hunger. An explanation of the process of marginalisation of peasants through the influence of five ??mediating factors?? is put forward. It is contended that by addressing the mediating factors through policies devised with the active participation of peasants, the marginalisation of peasants would be reduced or eliminated. This would allow peasants to forge an adequate livelihood in rural areas based on their independent farming, and thereby contribute to the achievement of food sovereignty.     

FDMS,Farmland Diversity and forage production unit Management Simulator

FDMS (which stands for Farmland Diversity Management Simulator) is an original software able to simulate the effect of farmland diversity and forage management practices on land use during a growing season in dairy farming systems. In this paper we describe how students, scientists or advisors can use this software to test different environmental scenarios (weather data and field characteristics) and management strategies at the farm scale.     

荷兰有机农业生产状况及启示

为探讨贵州有机农业生产的发展,采用收集二手资料、访谈以及参与式观察对荷兰的有机农业生产进行了调查研究。对荷兰的有机农业生产情况及社区支持型有机农场进行了介绍:政府对有机农业生产提供补贴,并建有专门的管理机构和学校。社区支持型有机农场把消费者看作是农场的重要组成成分,消费者参与农场的发展规划和各种活动,对农场的发展提出建议。笔者认为:贵州的有机农业生产应该考虑在学校中设立相关的培训课程,培养具有相关知识的学生;另可考虑发展社区支持型有机农场。     

不同年限稻鸭共作对水体藻类群落结构的影响

为探究不同规模、不同年限稻鸭共作系统水体藻类群落组成及多样性的差异,通过设置不同年限(4、20 a)和不同规模(0.067、0.200、0.333 hm~2)稻鸭共作田,利用高通量测序等手段,分析稻鸭共作田水体藻类多样性及群落结构的变化规律。结果表明:稻鸭共作田水体藻类的丰富度指数较非稻鸭共作田高,长期稻鸭共作田水体藻类Ace丰富度指数较短期共作田高,物种数增多;稻鸭共作田与非稻鸭共作田水体藻类优势种均为裸藻、绿藻、蓝藻,但稻鸭共作田绿藻、蓝藻的相对丰度高于非稻鸭共作田,另外稻鸭共作田规模大小影响蓝藻的相对丰度,规模越大蓝藻相对丰度越低;稻鸭共作田藻类多样性指数比非稻鸭共作田高,水体藻类群落结构差异较大,稻鸭共作系统的水体藻类群落结构表现出一定的相似性。冗余分析表明,对于稻鸭共作后期而言,影响非稻鸭共作田水体藻类群落结构的主要环境因子是溶解氧,而影响稻鸭共作水体藻类群落结构的环境因子是可溶性钾和pH。研究表明,长期稻鸭共作系统提高水体藻类多样性,改变藻类群落组成,从而影响农田水体生态环境。     

浅析中国耕作制度的演变

运用系统归纳和类比的分析方法,概述了中国农业耕作制度发展经历的3个阶段,即原始耕作、传统耕作和现代耕作;同时从整地、耕地、中耕、水利灌溉以及科技发展等方面对耕作制度发展的不同阶段进行了较为详细的论述,指出了农业耕作制度发展对农业科技的促进作用．而农业科技的发展对农业耕作制度的变革又起到了积极的推动作用。     

Some computer-based developments in sociology

Sociological data sets are now being computer analyzed by means of a variety of sophisticated procedures, to produce results that reflect the intricacy of social life. Computers also are being used to conduct simulations of social processes based on mathematical models and to collect the data for analysis. Portable computers allow computing power to be used in field studies, and the relatively low cost of computers is expanding the range of sociologists who use them. While opening up new research opportunities, computers also bring certain problems for social researchers and teachers.     

Improved fallows: a case study of an adaptive response in Amazonian swidden farming systems

Many smallholders in the Amazon employ swidden (slash-and-burn) farming systems in which forest or forest fallows are the primary source of natural soil enrichment. With decreasing opportunities to claim natural forests for agriculture and shrinking landholdings, rotational agriculture on smaller holdings allows insufficient time for fallow to regenerate naturally into secondary forest. This case study examines how Peruvian farmers use “improved fallows” as an adaptive response to a situation of decreasing soil fertility and how the farmers describe the rationale underlying the various actions taken in these modified fallow systems. The results indicate that farmers establish improved fallows using contextual ecological knowledge and various techniques to introduce a large diversity of tree species. This practice is also used to restore degraded land to agricultural production. The tasks of maintaining productivity on agricultural land and reforesting degraded areas is becoming increasingly urgent in the Amazon, making agricultural practices that involve reforestation and tree management highly relevant. Since swidden farming systems are the basis for the livelihoods of most Amazon smallholders, good farming practices elaborated by swidden farmers are important for sustainable small-scale family farming systems in the Amazon.     

Zuni farming and united states government policy: The politics of biological and cultural diversity in agriculture

Indigenous Zuni farming, including cultural values, ecological and biological diversity, and land distribution and tenure, appears to have been quite productive and sustainable for at least 2000 before United States influence began in the later half of the 18th century. United States Government Indian agriculture policy has been based on assimilation of Indians and taking of their resources, and continues in more subtle ways today. At Zuni this policy has resulted in the degradation and loss of natural resources for farming, reduction in the number of Zuni farmers and their control over farming resources, individualization of rights in farmland, consolidation of farm fields, and declining biological diversity in agriculture. The Zuni Sustainable Agriculture Project with the Zuni Irrigation Association and the Zuni community, are now working to revitalize sustainable Zuni farming, based on traditional values, knowledge, and technology, combined with modern knowledge and technology where appropriate. The United States government can support these efforts through appreciation of the need for Zuni control and the potential value of cultural and biological diversity.     

农田WebGIS服务系统设计和开发

基于MapXtreme组件构建了服务器端农田WebGIS服务系统。该平台提供WebGIS服务器与移动终端之间的数据交换服务,并利用Internet发布、接收和处理农田信息,提供农田生产决策支持。用户使用客户端浏览器就可以对农田信息进行浏览、查询、分析,并获取农田决策。通过该系统,农田管理者可以使用PDA通过GPRS将实时收集到的农田GIS信息(采样位置及该位置的土壤水分,土壤温度等)传输到WebGIS服务器上;服务器则远程收集农田实时信息进行分析计算,并根据分析计算结果进行农田生产决策,从而真正实现农田最优化管理。系统试运行表明,利用MapXtreme组件提供的WebGIS功能,实现了高效的农田GIS Web化管理。     

湖南稻田现代农作制特征及发展对策

研究湖南省农作制度的类型及其发展演变过程,对于指导该区域农作制度的发展具有十分重要的意义。利用近60多年来的年鉴统计数据,对湖南省稻田现代农作制特征、主体模式及布局、面临的问题和挑战进行分析,探讨其发展对策。首先,介绍了湖南省自然条件和气候资源、农作物种类、人均耕地等方面的基本情况;近60多年来农作制度的变化过程。湖南稻田现代农作制的特征主要体现为:种植业总产值占农业总产值的比重逐渐减少,林、牧、渔业所占的比例逐渐增加;粮食作物种植面积占农作物播种面积的比例下降,非粮作物和经济作物面积比重快速上升;水稻单产呈逐年上升的趋势。基于湖南省农作制特点,可划分为湘北商品型、湘中湘东城郊型、湘南外向型和湘西特色型现代农作制发展区。其次,阐明了湖南省发展稻田现代农作制所面临的问题,如人多地少、后备耕地资源不足,全省人均耕地仅为0.06 hm2;冬闲田面积增加,冬闲田面积在133万hm2以上,和经济发展与生态环境不协调、区域发展不平衡等一系列的挑战。最后,提出了从强化科技投入和政策支持、协调经济发展与农业生态环境、发展稻田多熟制、提升稻田现代农作制科学技术体系等发展对策。通过提出稻田现代农作制的战略调整,建立科学的现代农作制度技术体系,可为提升湖南省耕地综合生产能力、农业可持续发展提供科学理论依据。     

基于主成分分析的最小数据集的肥力指数构建

土地肥力评价对江西红壤地区土壤的农业生产非常重要。目前土壤肥力评价使用的指标多且没有统一标准,构建最小数据集肥力指标的肥力指数综合模型能够为农业管理者提供足够的肥力信息。通过对来自吉安县、余江县和兴国县240个土壤样品的全部肥力指标因子进行主成分分析提取最小数据集的肥力指标,并对全部指标建立的肥力指数和最小数据集建立的肥力指数进行相关分析和分类后的配对分析。结果表明提取的最小数据集的肥力指标因子有有机质、pH,阳离子交换链和粘粒含量4种,基于4种肥力指标建立的肥力指数和全部指标建立的肥力指数相关性极显著,相关性达0.92,分类后的整体准确率为88.75%,kappa因子为0.82,基于主成分分析提取的最小数据集建立的肥力指数和全部指标建立的肥力指数一致,能够较好代表全部肥力指标信息。