Bio-economic evaluation of farmers’
美国农业部BioPreferred简介

How is biobased defined in the 2002 “Farm Bill?
• Biobased products are defined as those determined by the U.S. Secretary of Agriculture to be commercial or industrial goods (other than food or feed) composed in whole or in significant part of biological products, forestry materials, or renewable domestic agricultural materials, including plant, animal, or marine materials.
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How does the Federal procurem categories of biobased products are bundled into a "round." These "rounds" become a draft Federal regulation and are published with a public comment period.
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Topic 2 The Federal Procurement Preference
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How does the Federal procurement preference work?
• On a continual basis, USDA selects and prioritizes categories of biobased products for identification as "preferred" products for Federal purchasing.
英语作文-农业科学研究和试验发展行业的农村社会治理与农民自治研究

英语作文-农业科学研究和试验发展行业的农村社会治理与农民自治研究Agricultural science research and experimental development in rural social governance and farmer autonomy。
Introduction:Agricultural science research and experimental development play a crucial role in the advancement of agricultural practices and the overall development of rural areas. This article aims to explore the significance of agricultural science research and experimental development in the context of rural social governance and the empowerment of farmers. By analyzing the relationship between these two aspects, we can gain insights into how agricultural science can contribute to the improvement of rural society and the autonomy of farmers.1. Enhancing agricultural productivity:Agricultural science research and experimental development focus on improving agricultural productivity through various means. By studying soil quality, crop varieties, and pest control methods, researchers can develop innovative techniques that enhance crop yield and quality. This, in turn, benefits farmers by increasing their income and improving their living standards. Moreover, the dissemination of these research findings to farmers enables them to adopt modern agricultural practices, further boosting productivity.2. Sustainable agricultural practices:The application of agricultural science research and experimental development promotes sustainable agricultural practices in rural areas. Through research, scientists can identify environmentally friendly farming methods that minimize the use of chemical inputs and reduce the negative impact on ecosystems. By adopting these practices,farmers can protect the environment, preserve natural resources, and contribute to the overall sustainability of rural communities.3. Technology transfer and capacity building:Agricultural science research and experimental development facilitate the transfer of technology and knowledge to rural areas. Researchers collaborate with farmers to introduce new technologies and farming techniques, providing training and capacity building opportunities. This enables farmers to acquire the necessary skills and knowledge to implement advanced agricultural practices. By empowering farmers with the latest scientific knowledge, they can make informed decisions, increase their productivity, and improve their overall livelihoods.4. Improved rural social governance:The integration of agricultural science research and experimental development into rural social governance enhances the overall management and development of rural areas. By addressing agricultural challenges and providing evidence-based solutions, policymakers can make informed decisions that benefit farmers and rural communities. The involvement of farmers in the research process also fosters a sense of ownership and empowerment, leading to better governance outcomes and increased farmer participation in decision-making processes.5. Farmer autonomy and empowerment:Agricultural science research and experimental development contribute to the autonomy and empowerment of farmers. By providing farmers with access to information, knowledge, and resources, they can make independent decisions regarding their agricultural practices. This autonomy allows farmers to adapt to changing market conditions, negotiate fair prices, and diversify their income sources. Additionally, the involvement of farmers in research and experimental development projects empowers them to actively participate in shaping agricultural policies and practices that directly affect their livelihoods.Conclusion:Agricultural science research and experimental development have a significant impact on rural social governance and the autonomy of farmers. By enhancing agricultural productivity, promoting sustainable practices, facilitating technology transfer, and improving rural social governance, agricultural science contributes to the overall development of rural areas. Furthermore, by empowering farmers through knowledge and participation, agricultural science enables them to take control of their own livelihoods and contribute to the sustainable growth of rural communities.。
英语作文-农业科学研究和试验发展行业的农村人居环境建设与农民生活质量改善研究

英语作文-农业科学研究和试验发展行业的农村人居环境建设与农民生活质量改善研究The intersection of agricultural science research and the development of rural living environments is a critical area of study that impacts the quality of life for farmers worldwide. The advancements in this field are not just about improving crop yields but also about enhancing the living conditions of those who work the land. This essay explores the various ways in which agricultural science research and experimental development can contribute to building better rural habitats and, consequently, improving the livelihoods of farmers.Rural Habitat Construction。
The construction of rural habitats is a multifaceted endeavor that involves more than just the building of homes. It encompasses the development of infrastructure, access to clean water, and the provision of energy sources. Agricultural science plays a pivotal role in this by offering sustainable solutions for housing that are both affordable and environmentally friendly. For instance, research into bio-based materials can lead to the creation of homes that are not only cost-effective but also have a lower carbon footprint.Water Management and Sanitation。
英语作文农业生物技术好处

英语作文农业生物技术好处Title: The Benefits of Agricultural Biotechnology。
Agricultural biotechnology, often referred to as agritech, is a field of science that involves using living organisms, such as plants, animals, and microorganisms, to improve agricultural productivity and efficiency. In recent years, agricultural biotechnology has gained widespread attention and acclaim for its numerous benefits to farmers, consumers, and the environment. In this essay, we will explore the advantages of agricultural biotechnology andits significant impact on global agriculture.Firstly, agricultural biotechnology plays a crucialrole in enhancing crop yields and quality. Through genetic engineering techniques, scientists can develop crops that are resistant to pests, diseases, and adverse environmental conditions. This resilience allows farmers to achieve higher yields while reducing the need for chemical pesticides and fertilizers, thus promoting sustainableagriculture. For instance, genetically modified (GM) crops such as Bt cotton and Bt corn have demonstrated increased resistance to insect pests, leading to improved yields and reduced crop losses for farmers.Moreover, agricultural biotechnology contributes tofood security by increasing the availability of nutritious and affordable food. By developing genetically modified crops with enhanced nutritional profiles, such as goldenrice fortified with vitamin A, researchers aim to combat malnutrition and micronutrient deficiencies in developing countries. Additionally, biotechnological advancements enable the production of biofortified crops that contain higher levels of essential vitamins and minerals, thereby improving public health outcomes and reducing theprevalence of dietary-related illnesses.Furthermore, agricultural biotechnology fosters sustainable farming practices and environmental conservation. By utilizing precision agriculture techniques, such as gene editing and marker-assisted selection, farmers can optimize resource utilization, minimize waste, andmitigate the environmental impact of agricultural activities. For example, the cultivation of drought-tolerant crops through biotechnology helps conserve water resources and mitigate the effects of climate change on crop production. Similarly, the development of nitrogen-efficient plants reduces the need for nitrogen fertilizers, thereby decreasing nitrogen runoff and its adverse effects on water quality and ecosystem health.In addition to its agronomic benefits, agricultural biotechnology contributes to economic development and poverty alleviation in rural communities. By increasing agricultural productivity and income opportunities for smallholder farmers, biotechnological innovations empower rural populations to escape the cycle of poverty and improve their livelihoods. For instance, the adoption of genetically modified crops has been shown to boost farm incomes and alleviate poverty in developing countries, where agriculture serves as the primary source oflivelihood for a significant portion of the population.Furthermore, agricultural biotechnology holds promisefor addressing global challenges such as climate change, population growth, and resource scarcity. Through research and innovation, scientists are developing novel biotechnological solutions to enhance the resilience and sustainability of agricultural systems in the face of evolving environmental pressures. From drought-tolerant crops to carbon-sequestering agricultural practices, biotechnology offers a range of tools and strategies to build climate-resilient food systems and ensure the long-term viability of agriculture.In conclusion, agricultural biotechnology offers a myriad of benefits for farmers, consumers, and the environment. By harnessing the power of biotechnology, we can enhance crop yields, improve food security, promote sustainable farming practices, and address global challenges facing agriculture. However, it is essential to recognize the importance of responsible stewardship and ethical considerations in the development and deployment of biotechnological innovations to ensure their safe and sustainable integration into agricultural systems. With continued research, investment, and collaboration,agricultural biotechnology has the potential to revolutionize global agriculture and pave the way for a more food-secure and sustainable future.。
研究生科技英语阅读课文翻译(1-10).

Unit 1 Genetically modified foods -- Feed the World?If you want to spark a heated debate at a dinner party, bring up the topic of genetically modified foods. For many people, the concept of genetically altered, high-tech crop production raises all kinds of environmental, health, safety and ethical questions. Particularly in countries with long agrarian traditions -- and vocal green lobbies -- the idea seems against nature.如果你想在某次晚宴上挑起一场激烈的争论,那就提出转基因食品的话题吧。
对许多人来说,高科技的转基因作物生产的概念会带来诸如环境、健康、安全和伦理等方面的各种问题。
特别是在有悠久的农业生产传统和主张环保的游说集团的国家里,转基因食品的主意似乎有悖自然。
In fact, genetically modified foods are already very much a part of our lives. A third of the corn and more than half the soybeans and cotton grown in the US last year were the product of biotechnology, according to the Department of Agriculture. More than 65 million acres of genetically modified crops will be planted in the US this year. The genetic is out of the bottle.事实上,转基因食品已经成为我们生活重要的一部分。
六级作文范文

技术与社会technolog y brought great convenience to our lives yet it also created multiple social problems. what do you think about technolog y? please write about your opinion. give two or three examples to illustrate your point.you should write about 200 word s neatly on answer sheet 2.参考范文the 20th century saw many great inventions, such as airplanes, motion pictures, television, telephone, computer, the internet, to list just a few. Each of these inventions bears witness to the amazing advancements in techn olog y in the past century. These inventions made our lives much easier and much more enjoyable.however, progress in technolog y is always a double-edged sword. People invented pesticides to kill pests but pesticides can pollute the environment by entering the water supplies and harming birds that eat the dead insects. Cell phone has greatly facilitated communication yet it has been proved that it poses danger to users’ health. What’s more, cell phones often go off during movies, concerts, classes, meetings,and libraries and create public nuisance. Automobiles have become an indispensable tool to the modern man but they consume great amounts of fuel, and create enor mous environmental problems. Also, many people are killed in car accidents every year. Interne t links tens of millions of people around the world but people are so addicted to the internet today that they don’t go out and do exercises.In a word, technolog y can be put to good use only when it’s used properly. People often find it hard to balance the convenience brought by modern technolog y and its potentially harmful effects. I believe the average people should be educated about the potential harm of technolog y and should always use it with a mind to promoting the public good.因特网与生活please write an essay on the topic “inte rnet, society and our lives”.you should write about 200 words neatly on answer sheet 2. (20 points)internet, society and our livesthere is increasing concern that those unable to use and access new techno logies marginalized from all aspects of economic and social activity. Internet has become an essential and powerful influence on our everyday lives. However, if used improperly, internet can put us at risks too.The internet is a wonderful source from whi ch we can retrieve valuable infor mation. Moreover, it facilitates our communication with people far away from us at a cost substantially less than that of traditional means of communication. Also, it can be an important building block to children’s learnin g because vast amount of infor mation is only clicks away. There is evidence sug gesting that computer use is linked to slightly better academic performance.However, we have sufficient evidence indicating that the internet can be a harmful influence on people. for example, its addictive power has increased children and youngsters’ time spent in front of the computer screens at the expense of other healthier physical activities, thus increasing their chance of getting overweight and short-sighted. In addition, children have limited ability of telling right from wrong andtherefore are subject to the potential contaminating influence of the harmful materials on the internet.In short, the negative influence of the internet should be minimi zed by diverting people, especially young people’s, interest to other areas of life. Like every other thing, internet is like a coin that has two sides. We must realize its harmful potentials while making use of it to achieve a better and more meaningful l ife.关于网络what do you think of internet?Internet plays an important role in our life. When you search through the net, the world seems smaller than ever, and New York seems no farther than your home town. Every hour, thousands of people, including young childr en, university students, scientists, businessmen, seek various information through Internet. You can discuss international crisis, football match, or your viewpoint on love and marriage with known or unknown people. In this way, you may make some friends, who share common views with you. When you are in trouble, you may ask for help through internet. What’s more, various meetings are held on the net. “what a wonder!”you may say. Yes, internet is one of the most interesting things man has ever invented. But as many other inventions, it has its own problems.First of all, there is too much rubbish on the net. some people are just over-enthusiastic to offer valueless information. This, in turn, has led to the increasing difficulty in finding what you want. Officials also find it hard to prevent internet from the invasion of criminals. And sometimes the cost is so prohibiting too many Chinese.There is no doubt that internet has contributed and will contribute greatly to our life because it is one of the most convenient ways of communication. Once you know it, you cannot resist it. Thousands of people have fallen in love with it. But won’t it serve us better if stricter administration is applied to it?环保read the news report below and write about human activities and the destruction of the environment based on the picture.新闻正文:北京三里屯街头竖立一个地球雕塑,一半是光洁的不锈钢,一半是各种动物的“化石”,让市民思考现代文明对人类生存环境的破坏。
Genetically modified foods -- Feed the World

Genetically modified foods -- Feed the World?If you want to spark a heated debate at a dinner party, bring up the topic of genetically modified foods. For many people, the concept of genetically altered, high-tech crop production raises all kinds of environmental, health, safety and ethical questions. Particularly in countries with long agrarian traditions -- and vocal green lobbies -- the idea seems against nature.如果你想在某次晚宴上挑起一场激烈的争论,那就提出转基因食品的话题吧。
对许多人来说,高科技的转基因作物生产的概念会带来诸如环境、健康、安全和伦理等方面的各种问题。
特别是在有悠久的农业生产传统和主张环保的游说集团的国家里,转基因食品的主意似乎有悖自然。
In fact, genetically modified foods are already very much a part of our lives. A third of the corn and more than half the soybeans and cotton grown in the US last year were the product of biotechnology, according to the Department of Agriculture. More than 65 million acres of genetically modified crops will be planted in the US this year. The genetic is out of the bottle. 事实上,转基因食品已经成为我们生活重要的一部分。
考研英语(二)阅读理解B新题型

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Bio-economic evaluation of farmers’perceptions of viable farms in western KenyaM.M.Waithakaa,*,P.K.Thornton b,c ,M.Herrero b,c ,K.D.Shepherd d a Eastern and Central Africa Programme for Agricultural Policy Analysis,P.O.Box 765,Entebbe,Ugandab International Livestock Research Institute,P.O.Box 30709,Nairobi,Kenyac Institute of Atmospheric and Environmental Sciences,University of Edinburgh,West Mains Road,Edinburgh EH93JG,UKd World Agroforestry Centre (ICRAF),P.O.Box 30677,Nairobi,KenyaReceived 14July 2004;received in revised form 7December 2005;accepted 30December 2005AbstractArable land in western Kenya is under considerable pressure from increasing human pop-ulation.Rural households depend on farming for at least part of their livelihood,and povertyrates are among the highest in nd is often depleted of nutrients,and for most farm-ers,access to inputs and markets is poor.There is a need to identify options that are manage-able within the context of the farmer’s resource base and the household’s objectives that couldimprove farm household well-being.In this study we integrated qualitative informal participa-tory approaches with quantitative mathematical programming and biophysical simulationmodelling.Households in four sub-locations in Vihiga District were clustered and pilot casesidentified.Meetings were held with farmers to elicit their perceptions of what their ideal farmwould look like,and how its performance might compare with their own farm’s performance.With farmers’help,a range of scenarios was analysed,relating to changes in current enterprisemixes,changes in current farm sizes,and changes in prices of staples foods and cash crops.Aconsiderable mismatch was found between farmers’estimates of their own farm’s perfor-mance,and what was actually produced.There seems to be a threshold in farm size of0308-521X/$-see front matter Ó2006Elsevier Ltd.All rights reserved.doi:10.1016/j.agsy.2005.12.007*Corresponding author.Address:International Livestock Research Institute,Old Naivasha Road,P.O.Box 30709,Nairobi,Kenya.Tel.:+25641322276/+25420630743;fax:+25641321777/+25420631499.E-mail addresses:m.waithaka@ ,mm.waithaka@ (M.M.Waithaka)./locate/agsyAGRICULTURAL SYSTEMS244M.M.Waithaka et al./Agricultural Systems90(2006)243–2710.4ha,below which it is very difficult for households to satisfy their income and food security objectives.Even for larger farms whose households are largely dependent on agriculture,the importance of a cash crop in the system is critical.There is a crucial role for extension services in making farmers aware of the potential impacts on farm revenue of modest changes in their farm management systems.We are monitoring nine households in the district,whose farmers have made some changes to their system in an attempt to increase household income and enhance food security.Ó2006Elsevier Ltd.All rights reserved.Keywords:Participatory modelling;Farmer perceptions;Household model1.IntroductionMany arable areas in sub-Sahara Africa are under severe pressure to increase pro-ductivity to feed a rapidly increasing human population.This is happening more so in degraded or low potential areas that are generally characterized by physical soil loss from erosion,nutrient deficiency,low organic matter,aluminium and iron tox-icity,crusting and moisture stress(Place et al.,2003).In addition,poor soil fertility management and continuous cropping exacerbate soil nutrient depletion.Because it is not possible to increase the area under production in the higher-potential areas, effective technologies and/or interventions are required that increase farm productiv-ity and enhance sustainability and thereby improve human well-being.Smallholder farming is difficult and problematic,but often it is the only option for a large proportion of rural populations in sub-Saharan Africa.Among the difficulties is the need to strike a balance between competing needs:to maximize labour produc-tivity,provide livelihoods and yet reduce land degradation and avoid falling into poverty traps in the wake of declining farm size and endemic low soil fertility.Pov-erty characterizes many subsistence households and threatens the hope of transform-ing rural populations to achieve a better standard of living.Options to improve this well-being do not lie with increasing land areas because most cultivable land is already in production,but rather lie in improving efficiency with existing resources and the current technology base.However,many farmers practice low-input subsis-tence farming with the aim of satisfying food requirements and basic income demands.For such systems both productivity and sustainability are at risk unless there is some use of external resources.We consider sustainable agricultural produc-tion in terms of the ability of food systems to meet current and future demand, thereby integrating production and distribution(Lynam,1994).Additionally,small-holders have tofind a balance between investing in inputs for crop and livestock pro-duction,growing food for the household,and generating income to buy food that cannot be grown on the farm and for health,education,and other household and social needs.Adoption of economically sustainable land management practices and technologies is constrained by shortage of land and capital resources(Shepherd and Soule,1998).For example,improved fallows are constrained by land shortages (Place et al.,2003);use of high value seeds and fertilizers by capital and access toM.M.Waithaka et al./Agricultural Systems90(2006)243–271245 markets(Salasya,2005;Omamo et al.,2002);intensive dairying and horticulture by high transport costs(Omamo,1998)and poor market access(Staal et al.,2002;Ehui and Pender,2005);late maturity cash crops such as tea or coffee and soil erosion con-trol measures by land tenure.Other factors that limit adoption of technologies are access to advice and credit.The main sources of income are sale of farm produce and income generated from off-farm activities such as earnings from self-employ-ment,wage employment and remittances.While off-farm activities may provide much-needed income to augment farming activities,they may take away productive labour from farms.When farmers sell their labour,they do so at the expense of their own farm activities and in the process,they may delay in preparing their own land for planting,weeding and/or harvesting,resulting in sub-optimal yields.The results of recent poverty mapping in Kenya places Vihiga among the poorest districts in the country(CBS,2003).With high poverty levels,farmers do not use high-return inputs such as certified seeds,fertilizers,disease and pest control measures,and rotations, but are limited to low-input,low-return enterprises.Mixed smallholder farming systems are generally highly complex,and are difficult to study satisfactorily.We lack methods that can be used to demonstrate to farmers the impacts of employing different technologies and/or interventions on their well-being,while taking a holistic farming systems’perspective.Many approaches only look at particular components of the farm,and do not do justice to the reality of farmers’decision-making,given the many and complex alternatives that abound. The major objective of this study was to help identify and develop viable technology options for targeted production systems that would help farmers to weigh up,in an ex ante sense,the impacts of different options.It was also anticipated that the out-puts of comparative analysis of different scenarios would help to inform policy, research and extension efforts.Some policy-related questions hinge on sustainable land use in the face of ever declining farm sizes.Research and extension issues relate to enhanced adoption of technologies that promote productivity and sustainable land use.The aim of this study was to improve understanding of farmers’conditions through the use of participatory approaches that incorporated simulation modelling, with a focus on farmer learning.This was considered necessary to ease adaptation of many of the complex,management–intensive techniques being developed in soil fer-tility,pest,crop and livestock management(Lynam,2002).Farmers should then be better able to evaluate for themselves potential benefits and trade-offs.In this paper,we discuss outcomes of farmers’perceptions of what may be an ideal farm versus what has been practiced on existing farms.Implications of modify-ing the ideal farm are compared with real farm situations,with respect to various sce-narios of interest to farmers:changes in current enterprise mixes,changes in current farm sizes(further sub-division of larger pieces of land and/or consolidation of smal-ler pieces of land),and changes in prices of staples and cash crops.We address the question,whether farmers are aware of the potential of alternative interventions,and if they are,what hinders or encourages their adoption.A second question addressed in this paper is whether there are options that are manageable within the context of the farmer’s resource base that could be utilized to improve farm household well-being in a sustainable manner.246M.M.Waithaka et al./Agricultural Systems90(2006)243–2712.MethodologyThe methods used in this study integrated household survey data,participatory identification of suitable interventions,and bio-economic modelling,because the actions of farmers are determined by interactions with the ecosystem on the one hand,and with the socio-economic environment on the other.The approach is being used in a wider study(named PROSAM or‘‘System prototyping and impact assess-ment for sustainable alternatives in mixed farming systems in high potential areas of East Africa’’)that seeks to improve ways of targeting interventions that improve the well-being of smallholders in mixed farming systems of east Africa through proto-typing and impact assessment(Booltink et al.,1999).The participation of farmers was seen as critical in identifying potential options and scenarios,and in validating the results.While most farm-scale models are often biased towards economic or biophysical aspects,this work seeks to integrate qualitative informal participatory approaches with quantitative and rigorous mathematical programming and biophysical simula-tion modelling.What we desired to achieve was a holistic view of the farming system, rather than a view of single components(Stoorvogel,1995;Jones et al.,1997).We followed the general approach taken by Castela´n-Ortega et al.(2003a,b):the use of a ruminant model to simulate alternative feeding systems for cattle(Herrero, 1997)and the use of a mathematical programming model to deal with the allocation of resources in the farming system(Herrero et al.,submitted for publication).To date we have not made use of crop simulation models,primarily because we do not have access to appropriate models of all the crops that are grown on smallhold-ers’plots in Vihiga.The basis of the methodology is prototyping.Prototyping was developed by Vere-ijken(1994)as a participatory approach that helps farmers improve their farming systems by continuous design and testing with the aim of reaching desires objectives. The process involves the development of a prototype that is then tested and possibly improved as a pilot case study.Options are assessed in terms of their likely impact on these different and sometimes competing objectives.Instead of using extensive exper-imental work to define the prototypes,as was done by Vereijken(1994),we used a process of clustering to characterize systems and participatory modelling to quantify, analyse and evaluate the behaviour of farming systems over a year.Simulation mod-elling of crop-livestock interactions at the farm level and scenario analysis allows us to assess andfine-tune farm management scenarios before testing them on-farm (Booltink et al.,1999).The framework for this integrated participatory modelling methodology(Fig.1) is adapted from Herrero(1997).The starting point is characterization of the system at different levels of aggregation.At the farm level,data related to land-use practices, crop and livestock management practices are collected through surveys and are used to identify prevailing production systems.Experiments and longitudinal monitoring of farm household activities,management practices,and economic performance of the systems are carried out in farms representing clusters of different systems.Farm-ers participate in selection of potential strategies,evaluation of their impacts on aM.M.Waithaka et al./Agricultural Systems90(2006)243–271247range of farmers’objectives and attitudes to risk,and sensitivity to the key manage-ment practices.Thefinal selection of the suitable interventions is carried out in par-ticipatory stakeholder workshops where the results of the simulations are presented to groups of farmers,extension agents,researchers and policy makers.Once the optimal resource management strategies have been selected,they are dis-seminated at two levels:farm and policy.At farm level,the selected pilot case study farms are used as demonstration farms to show the impact of the selected strategies. At a more aggregated level,the bio-economic analysis of the strategies selected are used to target and prioritize development policies at the regional level,such as credit schemes for local farming organizations and improvements in infrastructure,for example.Last in the dissemination phase is monitoring and evaluation of the outcomes and the impacts of the selected strategies once they are implemented at farm or policy level(Herrero,1997).Implementation of the methodology then becomes cyclic:as external or other conditions change(weather,prices,access to markets,etc.)the models are rerun or adapted,and new strategies are discussed and selected by stake-holders for implementation.In this study,a small number of pilot farms were then identified,that could be taken as being‘‘typical’’of each farming system type.The pilot cases so defined rep-resent subsistence,semi-subsistent and semi-commercial farming systems(ISNAR, 2004;Waithaka et al.,2004).The subsistence group is driven by diversified produc-tion mainly for household food requirements,while the semi-commercial group is248M.M.Waithaka et al./Agricultural Systems90(2006)243–271driven more by market orientation for inputs and outputs,with a resultant tendency towards specialization.The semi-subsistent group lies in between the other two. These farming system types were defined on the basis of cluster analysis that took into account structure,conduct and performance variables(Waithaka et al.,2004).A total of10farms representing all clusters were monitored over time,and with the use of participatory modelling,scenarios that could help them achieve their farm-ing objectives were explored.The modelling process took an interactive and iterative approach that involved livestock enterprise simulations with specific requirements on a daily basis for water,labour and nutrients,and quantification of the external and internal inputs required.The study area was located in Vihiga district.Vihiga district lies between1300and 1500m above sea level and is predominantly in the upper midland one(UM1)agro-ecological zone(Jaetzold and Schmidt,1983),with well-drained nitosols that support the growing of various cash and food crops.The area receives adequate bimodal rainfall that ranges from1800to2000mm/year.Although western Kenya is similar to other higher-potential areas such as central Kenya with respect to agroclimatic potential,access to technologies,technical assistance and land tenure,the region faces two main challenges:high population density and poor market access,which both condition prevailing production systems(Ehui and Pender,2005).Market access is a more important factor than population density in determining differences between central and western Kenya in dairy and crop production(Salasya,2005; Place et al.,2003;Staal et al.,2002).The average household has15persons living on0.89ha of land,creating a very high dependence on agriculture(Central Bureau of Statistics(CBS),2001).Farming is mainly low-external-input subsistence produc-tion with most of the farm area devoted to maize and other food crops while,the local Zebu is the predominant livestock in open grazing systems.Tea is the main cash crop and horticulture is not well developed.Horticulture and intensive dairying are limited by poor access to large urban or export markets and the nearest urban mar-kets are not large enough to stimulate surplus production.Due to limited growing of cash crops and hybrid maize,fertilizer use averages10.7kg of fertilizer per hectare, which is much lower than the already low Kenyan average of46kg/ha(Waithaka et al.,2003).Fertilizer use in Kiambu in central Kenya,which is close to a large urban market(Nairobi with over3million people–CBS,2001),is122kg/ha(Sal-asya,2005).The urban centres closest to Vihiga(Kisumu and Kakamega)have a combined population of some200,000people(CBS,2001).Vihiga has a high poverty incidence with60%of the households living below the poverty line(CBS,2003). Average total income is KSh56per household per day(1US$was equivalent to KSh77in mid-2005).The main sources of this income are wages and remittances, with an average of KSh11,096per year,while food and cash crops and other farm produce provide an average income of KSh5928per year(Waithaka et al.,2003).The project area was located in four sub-locations(Fig.2).Gavudunyi is in the north-eastern part of Vihiga,Mahanga is in the south and Magui and Mbihi are in the north-western fringe.While all areas are suitable for tea,dairy and maize production,in Gavudunyi and Mahanga tea is more prominent than dairying,in Magui both are prominent,while in Mbihi dairying is prevalent and there is notea production.Farmers’groups in these four sub-locations were asked to depict anideal farm based on a typical farm size in the sub-location.These groups included thepilot case farm (i.e.,the farm taken as being characteristic of that type)and their sur-rounding neighbours.The ideal farm was defined as one with a certain level ofresource endowment,and a certain number of key crops and livestock,and produc-tion techniques,e.g.,intercropping of maize and beans,stall feeding of exotic cattleand confinement of exotic chicken.Crop and livestock enterprises would be mixed inways that would satisfy the two major objectives that farmers have in farming here,namely,food security and basic income (Waithaka et al.,2002).The groups depicted the farms in drawings and for each plot,identified key cropand livestock enterprises and determined the input levels that would be required toreach the yields desired (Tables 1a and 1b ).The outcomes were compared with typ-ical farms representing the theoretical prototypes being developed with farmers inthe PROSAM project (Booltink et al.,1999).These nine farms (Fig.3)represent typ-ical households and include households with grade cows;households with maizeonly;households with tea and maize;and households with sugar cane and maize(Table 2).From the differences that were observed,farmers identified the constraints thathindered them from achieving ideal farm status and proposed interventionsthat would help them overcome the constraints.Through this approach,multipleFig.2.Kenya map showing Vihiga District (inset map)and Vihiga project sub-locations (main map).M.M.Waithaka et al./Agricultural Systems 90(2006)243–271249scenarios were tested within a selected year to evaluate the effects of interventions (evaluation of long-term effects of a single scenario over multiple years,to study the sustainability of a farming system,is possible but this has not been attempted as yet).For longer-term studies,the prototypes can be improved,new targets can be set,methodologies adapted,new sets of management scenarios defined,and then these can be modelled in an interactive and participatory way until the threshold val-ues of the desired objectives are met.Comparisons between what farmers considered to be ideal farm situations and what they currently practiced on their farms were made using the Integrated Mod-elling Platform for Animal-Crop Systems (IMPACT)tool developed by the Univer-sity of Edinburgh and the International Livestock Research Institute (ILRI)(Herrero et al.,2002,submitted for publication;Castela´n-Ortega et al.,2003a;Her-rero and Fawcett,2002).A key objective of IMPACT is to understand the effects of different management and policy interventions on smallholder farmers.To achieve that it adopts a holistic view of farms by considering:resources at the disposal of households –land,labour and capital assets;household objective of generating income and satisfying food requirements and allows buying of items that are in shortfall and selling of excess produce.IMPACT is not quite generic since generic systems do not exist.However,it has a set of routines to update and appendnew Fig.3.Real farms in Vihiga:(a)Farm 198(1.17ha,tea based),(b)Farm 162(0.32ha,sugarcane based),(c)Farm 043(0.88ha,tea based),(d)Farm 017(0.97ha,maize based),(e)Farm 242(0.53ha,maize based),(f)Farm 214(0.53ha,maize based),(g)Farm 107(0.16ha,milk based),(h)Farm 087(0.49ha,tea based),(i)Farm 150(0.77ha,tomato based).252M.M.Waithaka et al./Agricultural Systems 90(2006)243–271M.M.Waithaka et al./Agricultural Systems90(2006)243–271253)Fig.3(continued Array Fig.3(continued)Fig.3(continued)Fig.3(continued )254M.M.Waithaka et al./Agricultural Systems 90(2006)243–271Fig.3(continued)Fig.3(continued )M.M.Waithaka et al./Agricultural Systems 90(2006)243–271255256M.M.Waithaka et al./Agricultural Systems90(2006)243–271)Fig.3(continued Array Fig.3(continued)258M.M.Waithaka et al./Agricultural Systems90(2006)243–271information thus allowing it to be used in almost any system.Since IMPACT is a self-contained database which can also be linked to a wide suite of other analytical tools,it facilitates a better understanding of the way farming systems can be applied in pursuit of sustainable agriculture in developing countries(Herrero et al.,submit-ted for publication).From applications such as the one presented in this paper,a working version of IMPACT is available on CD ROM.On the limitations side, the model as used in this study only deals with an annual cycle,it does not deal explicitly with risk and requires understanding of optimization to build realistic sce-narios and to interpret the results.Data sets stored in IMPACT describe the land,labour,and crop-livestock enter-prise characteristics of a household,and these data can be exported to a mathemat-ical programming household model that provides a holistic view of a farm by integrating soils,crops and livestock interactions and is run using the software Xpress MP(Gue´ret et al.,2000).The household model was adapted to the smallholder systems in western Kenya by modifying the enterprises and integration between them,e.g.,pasture and livestock,maize and bean intercrops,maize in thefirst season and maize and or sorghum in the second season.The livestock model was used to simulate milk output in response to various diets,including Kikuyu grass(Pennise-tum clandestinum)pasture,maize stover,and Napier grass(Pennisetum purpureum). Essential characteristics of the mathematical model include an objective function that maximizes the household’s net cash income after satisfying household food requirements,subject to a set of constraints(e.g.,size of farm and plots,number of animals,household labour available)and variables that describe farming activities (e.g.,labour allocation by enterprise by month,and crop and livestock production costs)and a set of technical coefficients representing the variables’productive responses,e.g.,crop yields per hectare,milk yield per lactation,and input–output prices(Herrero et al.,submitted for publication).Cattle were used as a hedge against risk;the model was constrained to allow animals to remain on the farm,rather than being sold offafter each trial period.Model runs were not assessed over multiple time periods,because of the primacy farmers gave to food security and income, regardless of whether from farm or non-farm sources.For the same reason,analyses did not focus on returns to resources,and no explicit account was taken of risk,as farmers did not perceive this to be a key issue.3.Ideal farms3.1.VisualizationThe ideal farm was divided into a maximum of seven plots of single enterprises or enterprise mixes and management practices(Table3).Thefirst plot–the homestead–had the farmhouse,a patch of pasture where cattle were tethered,cattle sheds,and chicken coops.The other six plots were allocated to the main enterprises:tea,Euca-lyptus trees,maize,beans,sorghum,bananas,vegetables,sugar cane,orchard and Napier grass.Maize and beans were intercropped in thefirst season and pure maize260M.M.Waithaka et al./Agricultural Systems90(2006)243–271or sorghum was grown in the second season.From the farmers’point of view,such farms would be able to satisfy a household’s food and income requirements.Monthly labour requirements for crop and livestock management were calculated from monitoring surveys of the pilot cases and other typical households in Vihiga. Women provided10h of their time daily,while men and children provided six and two hours,respectively.Males were not generally involved in the homestead, and women normally undertook family chores,such as cooking and fetching fuel wood and water,as afirst priority.Children spent most of their time in school. Farmers also specified the amounts of fertilizer and manure used per enterprise and plot,which were used as indicators of soil nutrient balances.Farmers proposed crop yields and livestock off-take on a monthly basis,and these were compared with data obtained from existing farms in the monitoring surveys. The farmers also provided estimates of production costs for all enterprises based on expected yields,and these again were compared with the costs derived from the monitoring surveys.For products that could be traded,market buying and farm gate selling prices were used.Dietary preferences were considered in estimating energy and protein require-ments based on World Health Organization(WHO)standards(Ministry of Health, 1993).These requirements were equivalent to80%of the WHO standards,and adult equivalents were used to cater for differences in household composition.Forage pro-duction was linked to Napier grass,maize straw and natural pastures,which were allocated differently to the different cattle types(bulls,dry cows,calves,and lactating cows).3.2.Basis of the ideal and real farmsThe ideal farm in Gavudunyi was0.6ha,had two crossbred dairy cattle,20local chickens,vegetables,maize and beans,bananas,tea,Eucalyptus trees and arrow roots(Tables2and3).Some seven farmers attended the group discussions:all were less than50years old and two of them were women who managed their farms.Four of thefive farmers who had some off-farm income relied more on off-farm income than on income from farming.Three out of six farmers with farm income relied more on farm income than off-farm income.The ideal farm in Mbihi was0.4ha in size, had one grade cow,10local chickens,bananas,vegetables,sweet potatoes,maize and beans,and Napier grass.Eight farmers attended the group session:two of the eight men were over60years old.All farmers had both off-farm and farm income. Half of them relied more on off-farm income than farm income.The ideal farm in Magui was0.8ha in size,had two grade cows,50broilers,50exotic layers,20local chickens,three goats,bananas,vegetables,pasture,Napier grass,maize and beans, tea and Eucalyptus trees.Four farmers attended the group sessions:one woman and man were over60years old and the other men were in their thirties.The ideal farm in Mahanga was0.8ha in size,had two grade cows,20local chickens,bananas,vege-tables,pasture,Napier grass,maize and beans,tea and Eucalyptus trees.There were 10farmers in the group sessions:of these,five were women and there were four farm-ers over60years old.。