evolution. An extended definition is "the system of produc­tion used by a farmer as specified by the technology used, resources  available,  preferences held and goals pursued within a given agroecological and socioeconomic environ­ment" (Dillon and Hardaker, 1993).
     In the arena of discussion about the agricultural systems in Europe, references to the dichotomy between traditional or mainstream systems, on the one side, and emerging or al­ternative systems, on the other side, are frequent. However, there is no clear consensus about the scope of these concepts. As a first approach (Grudens-Shuck et al., 1998), alternative agricultural systems could be systems that include non-tra­ditional crops, livestock and other farm products; services, recreation, tourism, food processing, forestry and other en­terprises based on farm and natural resources; unconven­tional production systems such as organic farming; or direct marketing and other entrepreneurial marketing strategies. A European prospective analysis of agricultural systems (Libeau-Dulos and Cerzo, 2004) shows that the principal alternative agrosystems coexisting with mainstream agricul­ture are organic farming, integrated production, conserva­tion agriculture and agriculture under guaranteed quality. Other, less widely used agrosystems in the EU, include preci­sion agriculture, short-chain agriculture, urban agriculture, agriculture paysanne and permaculture.
     Farms are becoming specialized, increasing in size and declining in number. In Eastern Europe, farms were first in­dustrialized after WWII, although private small-scale farm­ing continued to exist. Food chain organizations developed towards global, linear and centralized structures with re­gional specialization (McFetridge, 1994; Royer, 1998; Cook and Chaddad, 2000; Reardon and Barrett, 2000; Hendrick-son et al., 2001; Harwood, 2001).

5.4.3.2 Uncertainties of the future
Examples of questions about the future are:
•     What is the economic viability of family farm systems? Will the trend toward larger, capital intensive farms continue? Will the marketplace support farms that pro­duce specialty products for niche markets?
•     Will prices and subsidies lead to the broadening of agri­cultural systems, or on the contrary to their reduction? What role will the transfer of existing technologies and the development of new ones play? How will improved analytical methods, increased traceability and reduced risks of fraud in the agricultural industry develop? Will the dissemination of biotechnology facilitate the emer­gence of new alternative systems? What could be its im­pact on precision agriculture, for example?

5.4.3.3 Consequences for AKST
The adoption of a new agricultural production system in­volves changes in the way holdings are managed; this makes the presence of a science and technology transfer system capable of meeting the new requirements of farmers espe­cially important. The availability of such a system there­fore strongly influences the choice of production systems that involve substantial changes, as is the case with organic farming, (which recovers traditional practices) and conser­vation agriculture (which experiments with new practices). The influence of this factor on the adoption of agriculture

of certified quality is dictated by marketing and distribu­tion criteria; in fact, this agrosystem facilitates acquisition of better knowledge, and ergo fulfillment of consumers demands.
     Farmers' willingness to make the transition from main­stream agricultural practices is not enough if they do not have access to the technology required. Hence this factor strongly affects the selection of agrosystems whose practices require the use of new technologies (e.g., integrated farming and conservation agriculture). The choice of organic farm­ing involves the use of natural resources, thus requires good knowledge about soils, biological pest and disease control, organic fertilizers. If conservation agriculture develops not only in large farms, for specific production types (cereals, wood crops), but also in smaller farms, substantial invest­ments in special machinery will be necessary. Production and distribution of AKST must be carefully examined if al­ternative agricultural systems are to be developed.

5.4.4 Agricultural labor and organizations
Migrant labor represents a high proportion of the work­ers in the agrifood sector, especially in parts of the United States and the southern countries of Europe. An increasing number of these laborers have come illegally. Enforcement of immigration law would force undocumented workers to leave the countries. The loss of labor force cannot be offset by mechanization and technological advancements alone. Changes in migrant labor could lead to higher wages, and thus higher prices, going out of business or moving produc­tion overseas.

5.4.4.1 Labor and gender dynamics: ongoing trends
In 2003, in the European Union, agriculture provided jobs for 13.3 million people, representing 6.6% of total employ­ment. The national distribution of employment in agricul­ture was extremely uneven. There were 5.8 million people employed in agriculture in the 13  "old" Member States, where employment in agriculture made up only 3.6% of total employment. In the Eastern European countries of the EU, there was an average of 12.4% of total employment in agriculture (EIROnline, 2005).
     The composition of labor in agriculture has changed over time, particularly with the sector being affected by dif­ferent stages of economic development (Hayami and Rut-tan, 1985). Four major trends affect the labor situation: important use of migrant labor in agriculture, growing un­employment in rural areas, aging farmers and enlargement of skills needed to be a farmer. There are no major territorial discrepancies in these trends (Brouwer, 2006).
     In North America and Europe, an important proportion of workers in the three agrifood sectors (farming, fishing and forestry; meat and fish processing; food service) are mi­grants. They are especially important for crop agriculture. In the United States, a significant majority of farmworkers lack proper work authorization and immigration status (Kandel and Mishra, 2007). Two major proposals for im­migration reform could lead to reduction in the farm labor supply. Enforcement would force undocumented workers to leave the countries. Legalization would give workers greater flexibility to seek other jobs and wages would probably rise. Possible responses to wage increases by firms would be to