Unravelling the rationale of `overgrazing' and stocking rates in the beef production systems of Central Brazil using a bi-criteria compromise programming model

In Central Brazil, the long-term sustainability of beef cattle systems is under threat over vast tracts of farming areas, as more than half of the 50 million hectares of sown pastures are suffering from degradation. Overgrazing practised to maintain high stocking rates is regarded as one of the main causes. High stocking rates are deliberate and crucial decisions taken by the farmers, which appear paradoxical, even irrational given the state of knowledge regarding the consequences of overgrazing. The phenomenon however appears inextricably linked with the objectives that farmers hold. In this research those objectives were elicited first and from their ranking two, `asset value of cattle (representing cattle ownership)' and `present value of economic returns', were chosen to develop an original bi-criteria Compromise Programming model to test various hypotheses postulated to explain the overgrazing behaviour. As part of the model a pasture productivity index is derived to estimate the pasture recovery cost. Different scenarios based on farmers' attitudes towards overgrazing, pasture costs and capital availability were analysed. The results of the model runs show that benefits from holding more cattle can outweigh the increased pasture recovery and maintenance costs. This result undermines the hypothesis that farmers practise overgrazing because they are unaware or uncaring about overgrazing costs. An appropriate approach to the problem of pasture degradation requires information on the economics, and its interplay with farmers' objectives, for a wide range of pasture recovery and maintenance methods. Seen within the context of farmers' objectives, some level of overgrazing appears rational. Advocacy of the simple `no overgrazing' rule is an insufficient strategy to maintain the long-term sustainability of the beef production systems in Central Brazil.     

基于复合多目标方法的灌区水资源优化配置

针对传统灌区水资源多目标模型求解过程中难以兼顾多维配置要求的问题,基于目标协调度、可持续发展指数、目标实现度3个指标提出了一种复合多目标方法。为验证该方法有效性,以甘肃省黑河中游17个灌区间水资源优化配置为例,以经济效益、社会效益、生态效益为目标函数构建多目标优化模型,并分别使用传统方法与复合多目标方法进行求解。结果表明,使用复合多目标方法所获得的优化配置方案可以将灌溉水利用系数提高5.42%~7.57%。结果验证了传统多目标模型在协调多个冲突目标方面较单目标模型有显著优势,而复合多目标方法所获得的优化方案更能体现决策者对研究区域种植业发展与灌区水资源配置的多元要求。     

Modelling multiple objectives of land use for sustainable development

Sustainability is a human-centred concept that comprises multiple aspects and objectives of different interest groups. Sustainable development is not readily measurable, except as a compromise between different parts of society, of which some may try to represent future generations of mankind. To determine a sustainable development path in the relationship between agriculture and its natural environment, a profound knowledge of this complex system and its behaviour under different socio-economic conditions is necessary. We present a modelling system which consists of a set of hierarchically linked modules. These modules describe production activities in a way that allows an economic and ecological analysis of these techniques. The heart of the modelling system is a multiple goal linear programming model, which is generated by data base modules. Simulation of single farm models as well as regional models based on simultaneously optimised farm types is possible. The modelling system appears to be a highly flexible tool with respect to the number and type of farms, sites and production techniques. Environmental objectives can easily be included and different levels of goal achievement can be simulated. It is well suited for single farm analysis as well as for regional models, for static as well as dynamic approaches. It allows rapid adoption of the model and rapid calculation of scenarios. Therefore, it is suited for use in interactive environments with users which are interested in repeated runs with little changes in the goal function, prices, subsidies or technical coefficients. The results can be used for policy decisions as well as the strategic planning of individual farmers. Applications of the modelling system will be presented in following papers. In this paper the kind of information the model can generate and the circumstances of their usage are shown. ©     

Exploring the link between farmers' objectives and the phenomenon of pasture degradation in the beef production systems of Central Brazil

In Central Brazil, half the area under sown pasture suffers from the phenomenon of pasture degradation; overgrazing is believed to be the main cause. Farmers' objectives and their links to the practice of overgrazing have been explored to obtain a better understanding of the decisions related to the setting of the stocking rate. A survey of beef cattle farmers was carried out, preceded by an exploratory poll of experts on such production systems. The method of paired comparisons was used for eliciting and analysing farmers' objectives. ‘Intergenerational transfer’ and ‘cattle ownership’ are the most dominant objectives. Because cattle ownership is implicitly included in the assets involved in intergenerational transfer, possessing cattle assumes an outstanding importance in the hierarchy of farmers' objectives. These findings elucidate the paradox of overgrazing and provide a basis for treating the perception on the influence of objectives on the degradation phenomenon from being a conjecture to that of an empirically valid hypothesis. They also suggest the need for incorporating the objective ‘maximise the number of cattle owned’ in the analysis and modelling of stocking rate decisions.     

Cattle are cash generating assets for mixed smallholder farms in the Eastern Amazon

The presence of cattle in the Amazon region is controversial in terms of their ecological suitability and profitability compared with crops. Nevertheless, they are widely distributed in the study area in north-eastern Pará and, contrary to the common image of cattle on large ranches, a high proportion of them are kept on smallholder farms. To explain their presence, cattle are assumed to have benefits beyond physical production, such as complementing resource use or representing capital. To test this hypothesis, the costs and benefits of the three main agricultural activities, cattle, cassava and black pepper production, in terms of land, labour and capital productivity, were recorded in 37 small farms over a period of 15 months. To provide a longer perspective, benefits and costs of these activities were calculated for their assumed lifetime, which in the case of cattle, assumed a stable herd, derived from a deterministic herd model. The resultant values for land, labour and capital productivity of cattle were much lower than the values derived from direct observations during the study period, and were not as high as those for cassava and black pepper. Furthermore, the analysis of resource use in the farms showed that cattle production was not usually integrated with cropping activities, did not improve the use of available labour, and competed for land. Therefore, there had to be a reason for keeping cattle beyond their physical productivity. It was deduced to be their functional quality. Cattle could be disposed of quickly and easily at any time, in order to acquire large sums of cash or the equivalent in kind. The liquidity derived from keeping living stock was not matched by other agricultural activities or by the financial market. Hence, cattle turned out to be the best instrument of finance for the smallholder. Farmers were not interested in the continuous development of their herds, or sustainable production practices, and favoured low input management. Consequently, development plans relying on long-term, continuous commitments to pasture and cattle management are inappropriate. Instead, research and extension work should focus on simple, flexible and low-cost improvements to cattle keeping on crop-livestock smallholder farms, until credit programmes are available that replace the financing function of cattle.     

A timothy-beef production model for Atlantic Canada

A five-part timothy-beef deterministic simulation model was prepared to integrate information on various production processes and hence to improve the basis for management advice given by extension workers.The five parts or sub-models are: the growth of the timothy, harvesting the crop, storing it, converting the timothy and other feeds to beef and, lastly, the feeding of cattle and the disposal of manure. Costs and returns are estimated.The model structure and principal biological relationships are described in some detail. Sample outputs for three different cow-calf-feeder regimes are shown and compared.The uses, limitations and potential of the model are discussed.     

An agro-pastoral household model for the rangelands of East Africa

East Africa contains areas with some of the greatest large mammal biodiversity on the planet. These areas are key natural resources for the economic development of the region. They are also key areas for pastoralists who have co-existed with wildlife for millennia. Increasing populations, conflicts between wildlife and cattle, and the growth of agriculture, are all placing great pressure on these lands This paper describes the development of a pastoralist socio-economic model that is linked to the Savanna ecosystem model. In this way, options and scenarios could be investigated for their impacts not only on the ecosystem but also on pastoralist households and their welfare. The model, named PHEWS (Pastoral Household and Economic Welfare Simulator), tracks the flow of cash and dietary energy in pastoralist households using a simple set of rules. The model was calibrated for the Ngorongoro Conservation Area (NCA), northern Tanzania. The results of two population increase scenarios are presented. Model results indicate that all households in NCA depend to some degree on outside sources of calories, and that pastoralist welfare in NCA, even with small amounts of agriculture allowed, is under severe pressure at current human population levels. Strengths and weakness of the model are discussed, and next steps in its application identified.     

Spatial aspects of weed control

Interaction between weed control and weed spread is discussed. A computer simulation model is used to examine four practical control strategies, each differing in spatial and temporal aspects. The efficiency of the four strategies is assessed in economic terms, for three rates of weed spread. The four strategies were shown to differ in their costs. The differences became more marked as the rate of weed spread increased. Moreover, the ranking of the control strategies, in terms of relative cost, changed as the rate of weed spread changed.The model highlights the importance of weed spread to decision-making in weed control programmes and provides some policy guidelines. It also provides a framework for specific case studies.     

大规模定制农机供应链中供应商的优化选择

供应商的优化选择是农机企业搞好农机供应链管理的前提。为了更好地适应当前农机市场的变化,基于大规模定制的农机供应链中如何对供应商进行优化选择亟待研究。本文运用一定的量化方法确定了供应商选择的综合评价指标体系与模糊综合评价模型,为农机供应链中选择供应商的决策者提供较为科学、系统的评价基准。     

商业化肉牛繁育大数据平台设计与关键技术

针对当前中国肉牛繁育管理水平和信息化智能化水平不高等问题,本研究借鉴国际先进肉牛养殖国家的经验,建立了适合中国的商业化肉牛繁育大数据平台。该平台主要完成肉牛种质信息资源的整合,在线自动测定肉牛关键繁育性状,全程服务支撑肉牛繁育过程,形成肉牛种质资源大数据分析决策,并实现肉牛联合育种创新模式。本文详细介绍了商业化肉牛繁育大数据软件平台开发思路,包括数据中心的实现、软件平台前端开发技术和后端开发技术等,并总结了该平台的关键技术创新和模式创新内容,包括肉牛种质资源与良种管理系谱深度挖掘技术,非接触式繁育性状自动获取评价技术,以及多源异构信息融合提供智能决策支持等,为中国肉牛种业发展提供可持续发展的信息化解决方案,以促进肉牛育种整体水平的提高。     

Evaluation of productive rural land patterns with joint regard to the size,shape and dispersion of plots

With a view to its use in relation to land consolidation programmes, we present an approach to evaluation of land distributions that aggregates the influences of the size, shape and dispersion of plots on productivity and is designed for computer implementation in a geographical information system. It is envisaged that it will be useful for identification of areas in which land consolidation is required, for evaluation of consolidation projects, and for consolidation project optimization.     

基于Web的奶牛场管理信息系统

介绍基于JSP+SPrvlet+Javabean模式开发的、适合中型奶牛场使用的奶牛场管理信息系统,分为牛群管理、产乳管理、牛群繁殖、统计与分析、养牛场管理及系统管理功能6个方面,可以对奶牛及奶牛场各种技术数据进行分析与综合整理,是一种实用、经济和操作简便的奶牛场信息资料管理系统.     

基于计算机视觉技术的玉米叶绿素含量检测研究

植株叶片中叶绿素浓度的高低与植株进行的光合作用效率、植株的整体生长状况息息相关,在农业生产过程中,常常根据叶片中叶绿素含量(SPAD)的多少来精确的判断植物的生长状态,也是控制植株长势的依据。传统的叶绿素含量检测方式分光光度法,存在耗时长、步骤多、操作要求高等问题,而采用计算机视觉技术处理图像的过程更加准确、高效,不会像人眼分析时受到主观因素的影响导致偏差。为此,基于计算机视觉技术来检测玉米叶片中叶绿素含量,利用扫描仪采集玉米叶片的图像,将图像输送至计算机,然后通过软件处理图像,分割出图像中有效像素的颜色特征值,将特征值转换就可以得到玉米叶片中叶绿素。试验结果显示:利用计算机视觉技术可以准确地测定玉米叶片中叶绿素含量,进而进行合理施肥,避免浪费,对增加玉米的产量具有极大的价值。     

灌溉经济效益模拟计算及群决策优选灌溉方案

在对灌溉效益特点进行分析的基础上，指出灌溉方案决策中存在两种不确定性，即随机不确定性和模糊不确定性。并针对灌溉方案决策的这一特点，使用模拟方法，以经济净现值为指标对研究区的农业灌溉方案的经济效益进行模拟求解；使用群决策的方法对灌溉方案进行多人多目标决策，将个人的偏好集结成群体的偏好，避免各决策者因知识结构等因素的不同，做出不符合实际的决策。研究结果表明：该模型简单、通用，基于此模型做出的决策更符合实际。     

Optimal decision schemes for agricultural water quality management planning with imprecise objective

Agricultural activities are the main sources of water pollution to surface water and groundwater in rural areas. Extensive soil disturbance and application of fertilizer and manure in agriculture cause nonpoint source losses of soil and nutrients such as nitrogen and phosphorus. How to generate preferred decision schemes for agricultural activities that cause such nonpoint source water pollution is a critical issue for the decision makers. In this study, an inexact agricultural water quality management (IAWQM) model is developed and applied to a case study to generate optimal decision schemes for integrated water quality management within an agricultural system. The model is based on a hybrid fuzzy possibilistic robust programming approach, which improves upon the existing fuzzy possibilistic programming and fuzzy robust programming methods by allowing fuzzy information in the model's objective and constraints to be directly communicated into the optimization processes and resulting solutions. Optimal decision schemes for agricultural activities can be generated, including cropping area, manure/fertilizer applied, and livestock husbandry size, where implications of water quality/quantity restrictions for achieving regional economic development objectives are studied. The results of the case study indicate that useful information can be obtained through the proposed IAWQM model for providing feasible decision schemes, which reflect tradeoffs between economic and environmental considerations. The decision variables are useful for the decision makers to justify and/or adjust the decision schemes for agricultural activities through incorporation of their implicit knowledge on water quality management.     

自动化灌溉控制工程技术的研究与应用

现代化农业对作物生长微环境要求高,对灌水时间、灌水量、灌水部位、水肥营养供给等都有更精确要求,自动化灌溉控制工程技术正是支撑现代化农业的一项基础性技术措施.为此,山东省水科院技术人员,经过多年来的技术开发与工程实践,集成电子信息技术、远程测控网络技术、计算机控制技术及信息采集处理技术,通过计算机通用化和模块化的设计程序,构筑供水流量、压力、土壤水分、作物生长信息、气象资料的自动监测控制系统,进行水、土环境因子的模拟优化,实现灌溉节水、作物生理、土壤湿度等技术控制指标的逼近控制,从而将农业高效节水的理论研究提高到现实的应用技术水平。该项技术已针对山东省不同种植作物、不同灌溉措施进行了系列推广,逐步形成了一套成熟的完整的应用技术体系。     

奶牛身份射频识别系统的防冲突技术

为了提高奶牛身份的识别度,采用无线射频识别技术来识别奶牛身份的识别系统。该系统采用耳标式电子标签来标记奶牛的身份,并在计算机系统建立一个电子数据档案。由于奶牛身份识别系统实行一畜一标,奶牛养殖规模大,植入的电子标签众多,射频识别技术中多标签存在冲突,因此防止多标签冲突问题是研究的重点。防冲突算法有ALOHA算法和二进制搜索算法两种常见算法:当采用ALOHA算法时,电子标签过多会造成防冲突时间长,甚至会出现判断错误;二进制搜索算法虽然不会出现错误,但用时较长,且安全性差,将二进制搜索算法进行改进成为返回式二进制树形搜索算法,可以解决这些缺点。为此,提出了基于返回式二进制树形搜索算法设计的奶牛身份射频识别系统的防冲突技术,试验表明:该设计可以解决识别系统中的防冲突问题,使系统采集信息与奶牛身份信息一一匹配,且缩短了识别时间,能迅速识别电子标签。     

基于改进YOLO v3的肉牛多目标骨架提取方法

针对肉牛行为识别过程中,多目标骨架提取精度随目标数量增多而大幅降低的问题,提出了一种改进YOLO v3算法(Not classify RFB-YOLO v3,NC-YOLO v3),在主干网络后引入 RFB(Receptive field block)扩大模型感受野,剔除分类模块提高检测效率,结合8SH(8-Stack...     

Assessing the impact of small dams on vector borne disease

The creation of vector habitats and the increased incidence of malaria, schistosomiasis and other diseases following the construction of surface water reservoirs in hot climates are well known. Little attempt has been made however to quantify the health impact of such water resource development projects. It has been suggested recently (Jewsbury & Imevbore 1988) that small dams may pose a greater disease risk than large structures. In view of the fact that small projects are attractive for a number of important reasons (Carter 1989), this conclusion gives rise to some concern.The paper reviews the ecology of the mosquito vectors and the snail intermediate hosts of the major water related diseases, malaria and schistosomiasis. As a result of this review the reservoir surface area from the shore to a depth of 2 m is proposed as a measure of Vector Habitat Potential (VHP). It is then shown how a simple spreadsheet model can be used to quantify the VHP for a proposed reservoir site at any chosen water-level or as a time-series. This reservoir model is demonstrated using data for a proposed dam in Burkina Faso, West Africa. Finally it is shown how the reservoir model must be combined with studies of vector biology and human behaviour in order to quantify the disease risk of any proposed dam site. The full model will enable various sites (large and small) to be compared, or, for a single site, the effects of different water management strategies to be evaluated.     

农业信息化管理应用及发展

随着我国经济水平和科学技术的迅速发展,计算机技术已广泛应用于我国农业生产。把计算机技术引入到农业生产管理中,是现代科学技术发展的重要标志。将计算机技术与农业信息化管理结合在一起,能够对农业生产起重大帮助作用。信息化农业是将农业信息和农业技术知识结合在一起的一种新型农业,农业信息化可推动我国农业可持续发展。通过对计算机技术与农业信息化管理进行深入分析,提出农业信息化管理中的改进措施。