(Potrykus, 2001). However, nutritionists argue that Vitamin A can only be absorbed by the body if consumed with sufficient oils and fats, which is often lacking in many Third World diets, and socia1 scientists argue that some of the Vitamin A problem is caused by the social status of eating hulled, white rice, with a low Vitamin A content, and that better nutrition could as easily have been achieved by campaigning for the consumption of existing, more wholesome varieties of brown paddy rice (Schnapp and Schiermaier, 2001). This example illustrates that the potential effect of feeding malnourished people with golden rice varieties differs when seen from the perspective of the uni-disciplinary perspective of the plant scientist than from a perspective that also includes nutritional and social knowledge. Estimating consequences of conversion to organic farming is another subject where both ecological (Dalgaard et al., 1998), economic (Hansen et al., 2001), and social driving forces (Trewavas, 2001) are relevant to include. This is because conversion to organic farming is driven both by the ecological potential of this system compared to conventional fuming and by the socio-economic gains for farmers and the society.A common feature of the problems encountered in the development of sustainable food production is the need for feedback mechanisms between the different research disciplines and between decision-makers and researchers. This is because the decisions to be made must take into account both the functioning of natural ecosystems and the response of humans acting either as individuals or as part of society. Consequently soft and hard science mechanisms interact with one another, and a dialectical approach (Levins and Lewontin, 1985), where both top-down and bottom-up viewpoints are valued, becomes fundamental for the iteratve integration of information from multiple disciplines.7. Conclusions and perspectivesThe current driving force for agroeco1ogy is the need to facilitate the development of more sustainable agricultural systems. This emphasis on sustainability is drawing agroecology up from its roots in agronomy and eco1ogy to include elements of both sociology and economics. This study found that agroecology can currently be defined as the study of interactions between plants, animals, humans and the environmemt within agricultural systems. One of its hallmarks is that it integrates between scientific disciplines and scales.The first Green Revolution was achieved primarily through the development and application of technology. Whilst, successful in terms of food production, serious questions have been raised concerning the impact of these agricultural practices on the health of the cultivated land (Oldeman et al., 1991)_ Conway (1997) argued that a second Green Revolution is required. which is even more productive than the fist Green Revolution and even more "green" in terms of conserving natural resources and the environment. In addition to the productive and environmental aspects, the social and economic dimensions of agricu1tural systems must therefore also be considerad.In recent years, significant progress has been made in understanding the issue of scaling and in the development of appropriate techniques. The barriers to interdisciplinarity are mainly cultural and political not technical, and lying deeply embedded in the way science has developed, these barriers present the major obstacle