An expert system for the management of Botrytis cinerea in Australian vineyards. II. Validation

An expert system developed by Ellison et al. (1997) for the management of Botrytis cinerea in Australian vineyards was validated against actual vineyard practices and official recommendations for control of the pathogen, using historical test cases from grapegrowing regions in southern New South Wales and from the Riverland region of South Australia. Performance of the expert system was judged on its ability to reduce unnecessary spray applications in seasons free from disease and to improve the timing of spray applications when conditions favoured disease development. In the test cases where disease did not develop, the expert system recommended between two and five sprays. This was comparable to the number of recommendations by official sources of advice but was excessive compared to actual vineyard practice where no sprays were applied. Reasons for the over-recommendation of sprays by the expert system were proposed. In the test cases where B. cinerea was observed, the expert system recommended a comparable number of sprays to grower practice and fewer sprays than official sources. With regard to timing of spray applications, the expert system was the only source of knowledge where spray recommendations bore any relationship to critical periods in the epidemiology of B. cinerea. Problems encountered in the validation of the expert system are discussed.     

Optimal site-specific fertilization and harvesting strategies with respect to crop yield and quality response to nitrogen

Incorrect fertilizer decisions can be costly if quality of the output, in addition to yield, is influenced by the application rate, which contrasts the flat payoff function estimated for fertilizer by previous studies focusing only on quantity. This study aims at modelling economic potentials of the combination of site-specific fertilization and quality specific harvesting at the example of wheat (Triticum aestivum L.), in Germany. Crop yield and protein response data to different nitrogen fertilizer applications were used from 15 locations to simulate site-specific wheat management. Four different management strategies were compared using a step wise price function for wheat qualities: uniform management, completely separate management, site-specific fertilization with uniform harvest, uniform fertilization with quality-specific harvest. It was found that opportunity costs (>50 €/ha) may apply, if threshold values for crop qualities are missed. Separation of different qualities can reduce this risk and create incentives for producing higher qualities on heterogeneous fields. Completely separate management had an economic advantage of up to 30 €/ha for the gross revenue, while site-specific fertilization alone had only marginal economic effects. However, these advantages have to cover costs for the use of technologies used, to be economically preferable.     

神经网络在农业专家系统中的应用

介绍了专家系统的特点及农业专家系统的发展现状;提出了将神经网络理论应用于农业专家系统的设计方法,并分析了其优点;论述了基于神经网络的农业专家系统的结构、知识表示与获取、推理机制等;结合具体实例,给出了神经网络学习方法及专家系统运行过程。     

Changing systems for supporting farmers' decisions: problems,paradigms, and prospects

All correct reasoning is a grand system of tautologies, but only God can make direct use of that fact. The rest of us must painstakingly and fallibly tease out the consequences of our assumptions. (Herbert Simon in ‘The Sciences of the Artificial’, p.15)

Decision support systems (DSS), like other information systems (IS) before them, were designed to serve functions deemed by ‘management scientists’ to be potentially useful to managers. But the unwelcome fact is that the use of agricultural DSSs by managers of farms has been low. This paper probes possible reasons for this through interpretation of agricultural DSS case histories and several strands of relevant social theory. From nine cases of DSS development effort and 14 products interpreted comparatively, a number of generalisations are made that serve as reference points in the following search for explanation in theory.First, the nature of management practice of family farms is explored and differences between the internal structure governing personal action and the scientific approach to practice are contrasted. Next, the interaction between the nature of the particular action/practice and the nature of the DSS is explored. A DSS designed to provide integrated, optimal recommendations for management typifies the DSS as a proxy for a manager's decision process. Examples of elaborate expert systems that simply were not used dramatically illustrate the resistance of family farmers to have their decision processes by-passed. On the other hand, the DSS designed to serve as a tool in a modified decision process is shown to have experienced higher use, by deriving and exploiting ‘deep,’ abstract information about the system, by introducing a powerful ‘logic,’ or a combination of both.A number of the referenced case stories demonstrate the resurgence of the decision support mode whereby the simulator is in the hands of an expert intermediary as an alternative to easy-to-use software in the hands of a farmer. This is the mode of operational research/management science, which preceded the DSS.In comparison with hierarchical organizations, available options for overcoming the persistent ‘problem of implementation’ of the DSS in family farms are inherently weak. This focuses attention on the importance of the relationship between the DSS developer and the potential user. Drawing on a classic typology of possible configurations of ‘understanding’ between the scientist and the manager, four approaches to intervention are discussed. Three entail a degree of engagement that qualifies them as ‘participative.’ But one of these constitutes a departure from the DSS and broader IS traditions that places it in another paradigm. In this ‘mutual understanding’ relationship, intervention intent shifts from educating and persuading to recognition of and respect for other ways of viewing the world. This opens up the opportunities for co-creating information systems that utilise the comparative advantages of both practical and scientific knowledge. Intervention emphasis shifts from prescribing action to facilitating learning in actions.Although the DSS has fallen far short of expectations in its influence on farm management, the experience has been instructive in multiple ways to both farmers and professionals in agriculture. In many cases, farmers learned from the DSS and could then jettison it without loss. From disappointments scientists have sometimes learned what was needed to achieve a better outcome. From collated DSS experiences, important lessons for the future can be drawn.The paper concludes by conjecturing that the future of the DSS and related ISs, while more limited than once imagined, holds promise in four directions: a ‘small’ tool for aiding farmers' tactical decisions; a versatile simulator as a consultant's tool; a versatile simulator as the core of a facilitated ‘learning laboratory,’ and a formal framework that supports regulatory objectives in constraining and documenting farming practice.     

Model for predicting rainfall by fuzzy set theory using USDA scan data

This paper presents a fuzzy inference model for predicting rainfall using scan data from the USDA Soil Climate Analysis Network Station at Alabama Agricultural and Mechanical University (AAMU) campus for the year 2004. The model further reflects how an expert would perceive weather conditions and apply this knowledge before inferring a rainfall. Fuzzy variables were selected based on judging patterns in individual monthly graphs for 2003 and 2004 and the influence of different variables that cause rainfall. A decrease in temperature (TP) and an increase in wind speed (WS) when compared between the ith and (i − 1)th day were found to have a positive relation with a rainfall (RF) occurrence in most cases. Therefore, TP and WS were used in the antecedent part of the production rules to predict rainfall (RF). Results of the model showed better performance when threshold values for: (1) relative humidity (RH) of ith day, (2) humidity increase (HI) between the ith and (i − 1)th day, and (3) product (P) of decrease in temperature (TP) and an increase in wind speed (WS) were introduced. The percentage of error was 12.35 when compared the calculated amount of rainfall with actual amount of rainfall.     

宁夏南部山区农用残膜污染现状及治理方法

宁夏中南部地区大力推广地膜覆盖栽培旱作农业技术,取得了显著的经济和社会效益。目前,宁夏农膜年残留量高达2.19万t,农用残膜“白色污染”问题日趋严重。政府制定建立长效机制,强化政府监管、壮大加工龙头企业、完善回收网络和带动农户参与,逐步建立“宣传保捡拾率,清理农田残膜;网点保回收率,方便农户交售;企业保加工率,享受政策扶持”的“3保”工作机制。宁夏回族自治区人民政府按照“3有、3无”,“3个双约束”作为检查验收的主要依据,必将加快宁夏残膜污染治理步伐。      

‘More crop per drop’: how to make it acceptable for farmers?

In countries facing water scarcity, governmental water agencies try to transfer this constraint to farmers, e.g. by encouraging them to shift from traditional to localized irrigation methods to save water. However, water shortage is often much less a problem for farmers than soil limitations, their objective being mostly to maximize their income per cultivated area (US$ per hectare rather than per cubic meter of water). This discrepancy can only be solved if governments find ways to ‘transfer’ water scarcity, e.g. through economic incentives such as water pricing and/or subsidies. The aim of this study was to address the question of how to match the interest of both water managers and farmers. We aimed particularly at evaluating whether shifting to drip irrigation is a relevant way to save water and increase farmer's income.Our analysis was based on the interactive impacts among economic, environmental, technical and methodological parameters on the net productivity of two crops. We focused on the case study of Turkey considering two crops with contrasted gross productivity, tomato and cotton, characterized by partial vegetation cover during a large part of crop cycle. A 3D crop energy balance model was applied showing that crop transpiration is increased by up to 10% when shifting from furrow to drip irrigation. These results were used to correct the maximal evapotranspiration (ET_m), estimated with the simple “crop coefficient” (K_c) method, and then used to enhance net productivity estimation both for furrow and drip irrigation.The results suggest that water managers and farmers share a common interest in adopting drip irrigation of tomato. Inversely, interests divergence may increase with low/medium value crops as cotton; the combination between water pricing and subsidies could be a way of agreement, but it would require subsidies for irrigation equipment of at least 40%, for low water tariffs, to 60%, for high water tariffs, to make the transfer from furrow to drip irrigation acceptable. This approach appeared generic enough to be applied for other economic, technical or environmental conditions, to modernize irrigation by harmonizing constraints faced by water managers and farmers.     

基于网络平台的《食品工程原理》教学研究与实践

针对《食品工程原理》课程特点和传统课堂教学的局限性,在多年教学实践研究的基础上,充分发挥网络教学平台优势,将传统课堂教学与网络平台教学有机结合,取得了良好的效果。通过网络教学平台的应用,有效促使传播方式由以往的传授型向研究型转变,同时,显著提升了学生的工程素质和学习能力。为普通高校工程类课程解决庞杂内容与精简课时的矛盾提出了新思路,是保障课堂教学质量的新途径。      

基于“互联网+”的农业供应链新模式

“互联网+农业”是互联网经济环境下农业发展新模式,是推动农业现代化实现跨越式发展的利器。因此,基于“互联网+”视域下探究农业供应链发展新模式对于农业现代化发展具有现实意义。该文基于“互联网+”视角,结合农业发展大势,从商流、物流、信息流和资金流构建农业供应链新模式,以“互联网+”带动农业创新发展。      

Water requirement for irrigated rice in a semi-arid region in West Africa

The purpose of this study was to determine the water requirement of rice (Oryza sativa L.) in the areas of the Office du Niger (Niono, Republic du Mali, West Africa). Average annual rainfall is 600 mm and evapotranspiration exceeds precipitation in every month except August. Alluvial soils vary in texture from heavy clay to sandy loam and have very low infiltration rates. The water use of rice was measured by establishing the water balance of four irrigation units varying in size from 12 to 26 ha. Evapotranspiration was evaluated with ‘non-weighing’ lysimeters and varied in 1980 from 5.3 mm/day shortly after flooding and 7.1 mm/day during heading to 4.1 mm/day at ripening. The crop coefficients found in this study do not always correspond to those presented by Doorenbos and Pruitt (1977). The crop coefficient depended strongly on the soil cover and was 1.0 for 10–70% soil cover and increased linearly to 1.25 for 100% soil cover. This relationship between soil cover and crop coefficient can be used to improve the estimates of rice evapotranspiration from large irrigation units with incomplete soil cover. The peak evapotranspiration may be as high as 7.8 mm/day during a 10-day period under full soil cover. The peak water requirement during the period of dry land preparation does not exceed 6 mm/day on level fields. The amount of water needed to saturate the soil profile after the dry season varied from 122 to 302 mm. A significant difference was measured between the pre-irrigation gift on a level field (175 mm) and on a non-level field (255 mm), which indicates the importance of levelling.     

“农家乐”运营模式存在的问题及创新对策

以“农家乐”旅游运营模式的弊端及创新为主题,比较分析了3种“农家乐”旅游运营模式,提出了“农家乐”旅游的创新模式,即在适应网络发展背景下,遵循当前旅游市场消费者注重体验感的趋势,选择“政府+公司+社区+农户”的创新性的运用模式,旨在为“农家乐”旅游的运营模式提供有益借鉴。      

基于低影响开发理念的海绵校园建设方案研究——以江苏城乡建设职业学院海绵城市示范项目为例

“海绵校园”既是海绵城市在校园尺度的示范,又是海绵城市的有机组成部分。江苏城乡建设职业学院基于绿色校园建设基础,对校园海绵基底现状进行分析,采用雨水管理“四步”方案,通过“渗”、“滞”、“蓄”、“净”、“用”、“排”等技术措施,实现年径流总量控制率75%的目标。项目具有显著的环境效益、经济效益和社会效益,为运用低影响开发技术打造海绵校园提供借鉴和指导。     

基于神经网络推理的压缩机故障诊断专家系统

设计了一种基于神经网络推理的汽车空调压缩机故障诊断专家系统。此系统将传统专家系统与神经网络技术科学地加以综合,弥补了传统专家系统的诸多缺陷。专家系统的知识库由两部分组成,即浅层知识库和深层知识库。推理过程由神经网络完成,并带有解释说明模块,主要说明诊断结果的判定依据。实践证明,这种方法能较好地解决传统专家系统存在的问题,提高系统的诊断速度和准确率。     

石嘴山市智能水网构建

为了解决水资源的高效利用,石嘴山市实施了智能水网建设,其典型特点是“三网合一”和“一网多用”。介绍了智能水网的构成,分析了各项工程的位置、建设措施及作用。智能水网建设是优化提升水资源配置的需要,是建设水生态文明城市的需要,是实现石嘴山市经济社会可持续发展的需要。      

机床数控技术课程教学改革

在阐述机床数控技术课程目的和意义的基础上,对教学中存在轻视数控加工基础知识,教学方法、内容和条件存在的问题和原因进行了分析。提出了“以学生为主体,教师为主导”的教学思想,并对更新教学内容、方法和手段等进行了改革。通过措施运行激发了学生的学习积极性,实现了“要我学”向“我要学”的转变,达到“教”与“学”有机结合。      

Technical and economic criteria in agricultural production: A case for a systems approach to farm decision-making in the Pakistan Punjab

This paper defines the criteria of ‘technical’ and ‘economic’ efficiencies. The relationship between these criteria is identified, and its implications are discussed. These two sets of criteria do diverge, with ramifications both at the farm and the national levels. An illustration of their relationship at the farm level is provided by examining the nature of water allocation to crops in the Punjab of Pakistan. The divergences that exist between ‘technical’ and ‘economic’ efficiencies at both farm and national levels are highlighted by considering the process of mechanisation in the Punjab in some detail. Finally, it is pointed out how a ‘systems approach’ can accomodate both the technical and economic criteria and their interaction.     

构建《自然资源学》实践性教学体系

通过对《自然资源学》课程理论知识结构和应用价值分析,从3方面进行实践性教学体系的构建,包含把理论与实践内容相结合的课堂教学设计、试验实习设计和实践与应用支持平台的构建。在设计思路的指导下,逐步建立《自然资源学》实践教学体系,增强学生实践技能的培养和提高学习兴趣。      

奶牛疾病诊断专家系统语音服务平台结构与功能研究

农业信息化是目前农业发展的主要趋势,专家系统是农业生产过程中的得力助手;然而由于网络铺设以及农民的生活水平、思想意识等因素的影响,大部分农村地区根本无法使用专家系统,使得专家系统与农民脱节,严重影响和制约了农业信息化的发展.为此,提出了面向奶牛疾病诊断专家系统的语音服务系统的解决方案,适合于农业信息传递,特别是偏远地区用户可以通过语音服务系统远程获取专家系统知识.结果表明,用户可以通过固定电话或移动电话与本系统进行通讯,在系统的语音提示下进入到不同的子系统,通过不同的功能模块满足用户的需要.     

张掖市经济林产业发展的思考

当前,经济林产业的发展已进入到一个崭新的阶段,各地把发展经济林作为活跃农村经济的特色产业、调整种植业结构的主导产业和推进山区农民脱贫致富的支柱产业来抓,经济林产业发展步伐不断加快。其正在逐渐成为促进区域经济发展的支柱产业和解决“三农”问题的重要途径,为张掖市的“生态立市”发挥着越来越重要的作用。