ABSTRACT
According to United Nations projections, the global population will reach 9 billion by 2050 and will likely exceed 10 billion by 2100 (United Nations Department of Economic and Social Affairs 2011). Historically, increases in global food demand have been met by intensifi cation of agriculture or by bringing new land into cultivation (Fitter 2012). The agricultural revolution of the twentieth century termed the green revolution saved hundreds of millions from starvation by modernizing agricultural management practices, developing better irrigation systems and creating new high-yielding varieties (HYV) of seed. While the productivity of most plants, especially cereal crops, signifi cantly increased, the development of HYV meant that traditional varieties of seed were replaced by only a few selected varieties leading to increased crop homogeneity and vulnerability to diseases and pests. These new varieties generally required higher rates of chemical fertilizer intake and relied heavily on the use of chemical pesticides and herbicides. While our reliance on chemical-based components to meet food supply demands has allowed unprecedented agricultural productivity, there are increasing concerns that conventional agricultural practices are unsustainable and will be unable to provide long-term solutions for food production. Amongst other problems, intensive agriculture has led to increased water use, soil erosion, loss of soil fertility, presence of residual pesticides in soil and the environment and increased pesticide and herbicide resistance. Furthermore, availability of new farmland suitable for cultivation is increasingly poor due to urbanization, salinization, desertifi cation, soil degradation and other forms of land loss. A new approach is clearly needed.
