This Chapter has presented an analysis of the positive and negative impacts of AKST over the last 50 years, which allows us to address the key IAASTD question: "What are the development and sustainability challenges that can be addressed through AKST?" We highlight ten concerns that pose the key AKST challenges to improving agriculture's sustainability, while meeting the needs of a growing population dependent on a limited and diminishing resource base:

     First, the fundamental failure of the economic development policies of recent generations has been reliance on the draw-down of natural capital, rather than on production from the "interest" derived from that capital and on the management of this capital. Hence there is now the urgent challenge of developing and using AKST to reverse the misuse and ensure the judicious use and renewal of water bodies, soils, biodiversity, ecosystem services, fossil fuels and atmospheric quality.

     Second, AKST research and development has failed to address the "yield gap" between the biological potential of Green Revolution crops and what the poor farmers in developing countries typically manage to produce in the field. The challenge is to find ways to close this yield gap by overcoming the constraints to innovation and improving farming systems in ways that are appropriate to the environmental, economic, social and cultural situations of resourcepoor small-scale farmers. An additional requirement is for farm products to be fairly and appropriately priced so that farmers can spend money on the necessary inputs.

     Third, modern public-funded AKST research and development has largely ignored traditional production systems for "wild" resources. It has failed to recognize that a large part of the livelihoods of poor small-scale farmers typically comes from indigenous plants (trees, vegetables/pulses and root crops) and animals. The challenge now is to acknowledge and promote the diversification of production systems through the domestication, cultivation, or integrated management of a much wider set of locally-important species for the development of a wide range of marketable natural products which can generate income for the rural and urban resource poor in the tropics-as well as provide ecosystem services such as soil/water conservation and shelter. Those food crops, which will be grown in the shade of tree crops, will need to have been bred for productivity under shade.

     Fourth, AKST research and development has failed to fully address the needs of poor people, not just for calories, but for the wide range of goods and services that confer health, basic material for a good life, security, community wellbeing and freedom of choice and action. Partly as a consequence, social institutions that had sustained a broaderbased agriculture at the community level have broken down and social sustainability has been lost. The challenge now is to meet the needs of poor and disadvantaged people-both as producers and consumers, and to reenergize some of the traditional institutions, norms and values of local society that can help to achieve this.

     Fifth, malnutrition and poor human health are still widespread, despite the advances in AKST. Research on the few globally-important staple foods, especially cereals, has been at the expense of meeting the needs for micronutrients, which were rich in the wider range of foods eaten traditionally by most people. Now, wealthier consumers are also fac

ing problems of poor diet, as urban people are choosing to eat highly processed foods that are high in calories and fat, while low in micronutrients. In addition, there are increasing concerns about food safety. The challenge is to enhance the nutritional quality of both raw foods produced by poor small-scale farmers, and the processed foods bought by urban rich from supermarkets. A large untapped resource of highly nutritious and health-promoting foods, produced by undomesticated and underutilized species around the world, could help to meet both these needs. Negative health impacts have also arisen from land clearance, food processing and storage, urbanization, use of pesticides, etc., creating procurement and marketing challenges for food industries and regulatory challenges for environmental and food safety organizations.

     Sixth, intensive farming is frequently promoted and managed unsustainably, resulting in the destruction of environmental assets and posing risks to human health, especially in tropical and sub-tropical climates. Many practices involve land clearance, soil erosion, pollution of waterways, inefficient use of water, and are dependent on fossil fuels for the manufacture and use of agrochemicals and machinery. The key challenge is to reverse this by the promotion and application of more sustainable land use management. Given climate change threats in particular, we need to produce agricultural products in ways that both mitigate and adapt to climate change, that are closer to carbon-neutral, and that minimize trace gas emissions and natural capital degradation.

     Seventh, agricultural governance and AKST institutions alike have focused on producing individual agricultural commodities. They routinely separate out the different production systems that comprise agriculture, such as cereals, forestry, fisheries, livestock, etc, rather than seeking synergies and optimum use of limited resources through technologies promoting Integrated Natural Resources Management. Typically, these integrating technologies have been treated as fringe initiatives. The challenge now is to mainstream them so that the existing set of technologies can yield greater benefits by being brought together in integrated systems. A range of biological, ecological, landscape/land use planning and sustainable development frameworks and tools can help; but these will be more effective if informed by traditional institutions at local and territorial levels. Because of the great diversity of relevant disciplines, socioeconomic strata and production/development strategies, sustainable agriculture is going to be more knowledge-intensive than ever before. This growing need for knowledge is currently associated with a decline in formal agricultural extension focused on progressive farmers and its replacement by a range of other actors who often engage in participatory activities with a wider range of farmers, but who often need greater access to knowledge. Thus part of the challenge is to reinvent education and training institutions (colleges, universities, technical schools and producer organizations), and support the good work of many NGOs by also increasing long-term investments in the upstream and downstream transfer of appropriate knowledge.

     Eighth, agriculture has also been very isolated from nonagricultural production-oriented activities in the rural landscape. There are numerous organizational and conceptual