to the poor (Shah et al., 2000). Credit schemes focusing on women also can have a positive effect on poverty allevia­tion (Van Koppen and Mahmud, 1996). By improving the precision of water delivery, these technologies can also help to increase water use efficiency, under the right conditions. There are different niches where these technologies are use­ful. In general treadle pumps are most suitable when water tables are within 2-4 m of soil surface. This situation is com­mon in monsoon Asia, and exists when treadle pumps are linked to rainwater harvesting structures, but is relatively rare outside wetland or direct pumping from lakes and wa­ter bodies in Africa.

Groundwater resources. Groundwater can provide flexible, on-demand irrigation to support diversified agriculture in all climate zones. Sustainable management requires that aquifer depletion be minimized and water quality be pre­served.  Overwhelming evidence from Asia suggests that groundwater irrigation promotes greater gender, class, and spatial equity than do large irrigation projects. Evidence from Africa, Asia, and Latin America also suggests that groundwater is important for poor farmers to improve their livelihoods through small scale farming based on shallow groundwater (Shah et al., 2007). Small scale technologies (see above) can improve access of the poor to groundwater resources. In all parts of the developing world key common priorities for AKST are to improve the data base, upgrade the understanding of groundwater supply and demand con­ditions, and create effective programs for public education in the sustainable use of groundwater resources (Shah et al., 2007). Participatory approaches to sustainable groundwater management will need to combine supply-side AKST such as artificial recharge, aquifer recovery, inter-basin transfer of water, with demand-side AKST such as groundwater pricing, legal and regulatory control, water rights and with­drawal permits (see chapter 7), and promotion of water-saving crops and technologies.

Decreasing land degradation. Water use efficiency, which is often as low as only 40%, in irrigated areas (Deng et al., 2006), can be increased. This is key to reducing recharge to naturally saline areas and water tables. Where soil salinity is high, leaching fractions must be applied to remove salt from the root zone, without adding it to groundwater or mobiliz­ing it to the river system; this is difficult and requires well thought out, innovative drainage solutions. Recognized op­tions for management of salinity risk, or to reduce existing areas of saline soil, are revegetation with alternative species, pumping to lower the water table and construction of ditch drains for control of surface water and shallow groundwa­ter (Peck and Hatton, 2003).
       Management of salinity is complex and requires in­tegrated solutions at catchment and basin scale with the key being to minimize mobilization of salt and reduce the amount for disposal—disposal through the stream system is undesirable and environmentally costly. All options for management of salinity risk are constrained by the econom­ics of dry land farming and pumping or drainage is further constrained by possible environmental impacts of disposal of saline water. In Australia, the bulk of effort has been di-

rected at "living with saline land and water," with immense public and private investment in tree planting and the search for new low recharge farming systems (Peck and Hatton, 2003). Practices to improve water use efficiency include biological mechanisms of water-saving agriculture and ir­rigation technologies, including low pressure irrigation, fur­row irrigation, plastic mulches, drip irrigation under plastic, rainfall harvesting and terracing (Deng et al., 2006).

6.7 Using AKST to improve Health and Nutrition

AKST can improve human health and nutrition through re­ductions in (1) malnutrition and micronutrient deficiencies; (2) food contaminants; and (3) the emergence and reemer-gence of human and animal diseases, including HIV/AIDS. Key driving forces over the coming decades for these chal­lenges include not just AKST, but also demographic change; changes in ecosystem services; global environmental change; reductions in freshwater resources; economic growth and its distribution; trade and travel; rate of technology develop­ment; governance; degree of investment in public health and health care systems; and others.
       In addition, some food systems are not providing the range of nutrients needed to ensure adequate nutritional status. Approaches to improve dietary quality are needed to ensure adequate availability, accessibility, and utilization of foods with nutrients appropriate to the needs of the popula­tion.

6.7.1 On-farm options for reducing malnutrition and micronutrient deficiencies
Integrated farm systems, based on a variety of foods, can help meet the challenge of micronutrient malnutrition (Ton-tisirin et al., 2002). Improving crop diversity is an impor­tant part of improving dietary diversity, and thereby dietary quality. The diversity of wild and cultivated traditional plant varieties in rural areas of low-income countries pro­vides many opportunities to identify high quality, but un­derutilized, nutritious foods. Increased research on locally adapted traditional varieties could lead to the development of improved varieties that are higher yielding or more resis­tant to pests and abiotic stresses such as drought. House­hold processing of wild foods collected by subsistence farm­ers as part of a traditional diet would increase storage life and make additional foods available during periods when food is inadequate. For example, solar drying techniques have been used to preserve foods such as mangoes, bananas and sweet potatoes.
        Possible improvement of these varieties through breed­ing is currently limited because private and public sector breeding programs rarely focus on minor crops. Identifying and exploiting the potential of these varieties will require increased research in both high- and low-income countries. In Kenya, when farmers produced underutilized leafy green vegetable   varieties,   consumption  was   increased   among farmers, and the producers found a market among middle and high income consumers who began to purchase these novel varieties (Frison et al., 2006). Once researchers iden­tify health promoting compounds in indigenous and under-