where 0.8 million hectares were planted in 2004 using this system (Malik, Yadav and Singh, 2005).

     Broader adoption of conservation agriculture practices would result in numerous environmental benefits such as decreased soil erosion and water loss due to runoff, decreased carbon dioxide emissions and higher carbon sequestration, reduced fuel consumption, increased water productivity, less flooding, and recharging of underground aquifers (World Bank, 2004a).

Agriculture, agrifood systems and value chains

Agrifood systems are described as including a range of activities involved at every step of the food supply chain from producing food to consuming it, the actors that both participate in and benefit from these activities, and the set of food security, environmental and social welfare outcomes to which food system activities contribute (Ericksen, 2006). They include the primary agriculture sector and related service industries (i.e., veterinary and crop dusting services); the food and beverage, tobacco and non-food processing sectors; the distribution sector (wholesale and retail); and the food service sector. Value chains are multinational enterprises or systems of governance that link firms together in a variety of sourcing and contracting arrangements for global trade. Lead firms, predominantly located in industrialized countries and comprising multinational manufacturers, large retailers and brand-name firms, construct these chains and specify all stages of product production and supply (Gereffi et al., 2001). The value chain perspective shifts the focus of agriculture from production alone to a whole range of activities from designing to marketing and consumption.

     Agrifood systems range from traditional systems that are localized where food, fuel and fiber are consumed close to the production areas using local resources, to large agrifood industries that are globalized and linked to integrated value chains. Traditional systems may include hunter-gathering and peasant agriculture that meet the needs of the community from local resources. The major traditional agrifood systems comprise small family farms that supply products to the local markets but are continuously being transformed in response to market signals. At the other end, there are large agrifood industries consisting of international or transnational companies that are globalized and integrated into complete value chains. These systems are continuously being transformed by market and consumer demands, with new agrifood systems emerging that consider social and environmental aspects and use technological innovations. Organic agriculture is an example, which showed rapid growth in the 1990s in Europe, where 4% of EU agricultural land area is now organic, compared with only 0.3% in North America (Willer and Yussefi, 2006).

     Agrifood systems have a strong influence on culture, politics, societies, economics and the environment, and their interactions affect food system activities. Agrifood system activities can be grouped accordingly: producing, processing and packaging, distributing and retailing, and consuming (Zurek, 2006). As the agrifood systems become more sophisticated and globalized, they have to adhere to regulations and standards to meet product safety and quality, and consumers' specific needs in order to survive. New and more innovative technology in food production, post-harvest

treatment, processing, packaging and sanitary treatment are now playing a more important role.

Agriculture and the environment

Land cover and biodiversity changes. Beyond its primary function of supplying food, fiber, feed and fuel, agricultural activity can have negative effects such as leading to pollution of water, degradation of soils, acceleration of climate change, and loss of biodiversity. Conversion of land for production of food, timber, fiber, feed and fuel is a main driver of biodiversity loss (MA, 2005b). Many agricultural production systems worldwide have not sufficiently adapted to the local/regional ecosystems, which has led to disturbances of ecosystem services that are vital for agricultural production. Requirements for cropland are expected to increase until 2050 by nearly 50% in a maximum scenario, but much less in other, more optimistic scenarios (CA, 2007; see Figure 1-11).

     Soil degradation has direct impacts on soil biodiversity, on the physical basis of plant growth and on soil and water quality. Processes of water and wind erosion, and of physical, chemical and biological degradation are difficult to reverse and costly to control once they have progressed. The Global Assessment of Human-induced Soil Degradation (GLASOD) showed that soil degradation in one form or another occurs in virtually all countries of the world. About 2,000 million hectares are affected by soil degradation. Water and wind erosion accounted for 84% of these damages, most of which were the result of inappropriate land management in various agricultural systems, both subsistence and mechanized (Oldeman et al., 1990).

Water quality and quantity changes. Access to enough, safe and reliable water is crucial for food production and poverty reduction. Most people without access to an improved water source are in Asia, but their number has been rapidly decreasing since 1995, which is less the case in sub-Saharan Africa, Latin America, West Asia and Northern Africa (see Figure 1-12).

     However, putting more water into agricultural services threatens environmental sustainability. Water management in agriculture thus has to overcome this dilemma (CA, 2007). Intensive livestock production is probably the largest sectoral source of water pollution and is a key player in increasing water use, accounting for over 8% of global human water use (Steinfeld et al., 2006). Excessive use of agrochemicals (pesticides and fertilizers) contaminates waterways. Better management of human and animal wastes will improve water quality. Agriculture uses 85% of freshwater withdrawals in developing countries, mainly for use in irrigation, and water scarcity is becoming an acute problem, limiting the future expansion of irrigation (CA, 2007). Water conservation and harvesting also have an important potential for rainfed farming (Liniger and Critchley, 2007) as water scarcity is widespread.

Climate change: Climate change influences and is influenced by agricultural systems. The impact of climate change on agriculture is due to changes in mean temperature and to seasonal variability and extreme events. Global mean temperature is very likely to rise by 2-3°C over the next