Soil and moisture conservation, and micro-irrigation techniques have been developed to increase crop yields by small farmers.

Many soil and moisture conservation and micro-irrigation techniques have been developed to increase crop yields by small farmers. Soil and moisture conservation techniques include tillage practices, planting grasses, such as vetiver, and other living barriers, terracing, bunding and contour planting (Tripp, 2006). Micro-irrigation techniques include drip irrigation, basin planting or "zai" pits, and the introduction of treadle pumps and water harvesting (Mupangwa et al., 2006). To reduce the quantities of water and nutrients used during crop establishment, ICRISAT and several NGO partners have promoted a "conservation agriculture" package based on basin planting; small basins (approx. 3375 cm3) are prepared during the dry season when labor demands are relatively low. Basin planting utilizes limited resources more efficiently by concentrating nutrients and water applications. For small-scale systems in dry areas of southern and western Zimbabwe, maize yields were 15-72% (mean = 36%) greater from basin planting than from conventional plowing and whole-field cultivation.

In many urban areas across the world, sewerage is used as source of water and nutrients in urban and peri-urban agriculture.

Global assessments show that in developing countries only a minor part of the generated wastewater is treated while the large majority enters natural water bodies used for various purposes including irrigation. Recent studies suggest that at least 2 to 4 million ha of land are globally irrigated with untreated, treated, diluted or partially treated wastewater (Furedy, 1990; Drechsel et al., 2006). Generally, it is estimated that about 25-100% of food demand in an urban environment is met through production of food in the same setting (Birley and Lock, 1999), while about 10% of wastewater generated in towns has further use in urban agriculture. These estimates take account urban horticulture, aquaculture and livestock; 25-80% of urban households engage in some form of agriculture. In many developing countries in Asia, Africa and Latin America, sewage sludge has been used for some time (Furedy, 1990; Strauss, 2000). The risks associated with downstream recycling wastewaters are especially great in countries within arid and seasonally arid zones (Strauss, 2000). New WHO Guidelines for the Safe Use of Wastewater, Excreta and Greywater (WHO, 2006) recognize the health issues concerning wastewater use in agriculture, but water pollution and its management will be an issue of concern for populations around the world for some time (Furedy, 1990; Dey et al., 2004).

Many river basins can no longer sustainably supply water for agriculture and cities.

Unsustainable use of water resources for irrigation means that extraction exceeds recharge. For example, large-scale irrigation since the 1960s has had devastating impacts on water resources and soil productivity in Central Asia. The water level of the Aral Sea has dropped by 17 m, resulting in a 50% reduction in its surface area and a 75% reduction in its volume. The resulting economic and health impacts to the Aral Sea coastal communities have also been serious (http://www.fao.org/ag/agl /aglw/aquastat/regions/fussr/index8. stm).

3.2.1.6 Advances in information and communications technologies (ICT)

Innovations in information technology have been essential for progress in biotechnology.

Genomics, proteomics and metabolomics generate large quantities of data that require powerful computers and large database storage capacities for effective use; advances in ICT have been fundamental to their success. The growth of the worldwide web has allowed data to be widely accessed and shared, increasing impact. The complexity and size of tasks such as describing the genome of model plants has led to global collaboration and data-sharing.

Climate and crop modeling is positively affecting crop production.

The increasing availability of climate data and the use of simulation models, globally, regionally and locally, are having a positive impact on agricultural production. Field-scale crop growth and yield simulation models can help define breeding traits and growing environments, and analyze G x E interactions (Muchow et al., 1994; van Oosterom et al., 1996; Sinclair et al., 2005). At a larger scale, global and regional climate models (GCMs and RCMs) are producing more accurate forecasts and there is collaboration between meteorologists and crop scientists on seasonal weather forecasts (Slingo et al., 2005; Sivakumar, 2006) ranging from months to weeks; these forecasts have proved of practical and financial benefit in countries such as Australia (Stone and Meinke, 2005). More attention needs to be given to providing forecasts to farmers as climate change increases in importance.

Remote sensing and site-specific management benefit from ICT.