involving local communities tend to use water more sustainably (Ruf, 2001; Molle, 2003) than modern schemes. For example, by 2001 the Syr and Amu Dar'ya rivers had decreased to less than half their size in 1957 due to intensive irrigation of cotton and rice in the former Soviet Union (UNEP, 2002).

The Lake Victoria Basin project is an integrated watershed approach to assessing the biophysical and socioeconomic effects of environmental degradation.

Lake Victoria, the world's second largest lake (68,000 km2), is located in an agricultural area with high population density (28 million people on 116,000 km2 of farm land). It displays multiple water degradation problems associated with high river sediment loads from erodible soil, and unsustainable farming practices such as intense cultivation and nutrient depletion. The local communities have serious and wide-scale socioeconomic problems as a result of low crop productivity. The Lake Victoria Basin project has used an integrated watershed approach involving participatory monitoring and evaluation, coupled with spectral reflectance and remote sensing, to characterize the problems and develop agroforestry interventions and livestock exclusion trials to promote more environmentally sustainable farming practices (Swallow et al., 2002).

3.2.2.1.9 Organic systems and biointensive agriculture
Organic agriculture includes both certified and uncertified production systems that encompass practices that promote environmental quality and ecosystem functionality. Organic agriculture is based on minimizing the use of synthetic inputs for soil fertility and pest management. From a consumer viewpoint, this is valuable for avoiding the perceived health risks posed by pesticide residues, growth-stimulating substances, genetically modified organisms and livestock diseases. There are also environmental benefits associated with organic production practices that arise from lower levels of pesticide and nutrient pollution in waterways and groundwater (FAO/WHO, 1999).

Organic agriculture is a small industry (1-2% of global food sales) but it has a high market share in certain products and is a fast growing global food sector.

Although global food sales are minimal (1-2%), there are some products with a substantial market; in Germany organic milk products have >10% market share and organic ingredients in baby food comprise 80 to 90% of market share. In the USA, organic coffee accounts for 5% of the market although it is only 0.2% worldwide (Vieira, 2001). The total market value of organic products worldwide, reached US$27.8 billion in 2004. There has been annual market growth of 20-30% (growth in the overall food production sector is 4-5% per year) (ftp://ftp.fao.org/paia/organicag/ 2005_12_doc04.pdf).

Food labeled as organic or certified organic is governed by a set of rules and limits, usually enforced by inspection and certification mechanisms known as guarantee systems.

There has been a steady rise in the area under organic agriculture. With very few exceptions, synthetic pesticides, mineral fertilizers, synthetic preservatives, pharmaceuticals, sewage sludge, GMOs, and irradiation are prohibited in organic standards. Sixty industrialized countries currently have national organic standards; there are hundreds of private organic standards worldwide (FAO/ITC/CTA, 2001; IFOAM, 2003, 2006). Regulatory systems for organics usually consist of producers, inspection bodies, an accreditation body for approval and system supervision and a labeling body. There are numerous informal regulatory systems outside of formal organic certification and marketing systems (peer or participatory models) that do not involve thirdparty inspection and often focus on local markets. The harmonization of organic standards is an issue in international trade. Harmonization has been facilitated by the organic agriculture global umbrella body, the International Federation of Organic Agriculture Movements (IFOAM) and through Codex guidelines. The Codex guidelines concern the production process and provide consumer and producer protection from misleading claims and guide governments in setting standards (FAO/WHO, 1999; El-Hage Scialabba, 2005). The extent of non-certified systems is difficult to estimate, particularly in developing countries.

Worldwide, more than 31 million ha of farmland were under certified organic management in 2006.

Globally organic production covers 31 million ha on more than 600,000 farms in approximately 120 countries. Organic production is rapidly expanding with an aggregate increase of 5 million hectares from 2005 to 2006. Australia has the largest area of land under organic certification systems (12.2 million ha), but Latin America has the greatest total number of organic farms (Willer and Yussefi, 2006). By region, most of the world's certified organic land is in Australia/Oceania (39%), Europe (21%), Latin America (20%), and Asia (13%). In Switzerland, more than 10% of all agricultural land is managed organically. Large areas, particularly in developing countries and some former Soviet States, are organic by default (i.e., noncertified), as farmers cannot afford to purchase fertilizers and pesticides (Willer and Yussefi, 2006). The extent of such nonmarket organic agriculture is difficult to quantify, but >33% of West African agricultural production comes from noncertified organic systems (Anobah, 2000). In Cuba which has made substantial investments in research and extension, organic systems produce 65% of the rice, 46% of fresh vegetables, 38% of non-citrus fruit, 13% of roots, tubers and plantains and 6% of the eggs (Murphy, 2000).