There has been a decline in government funding to agricultural extension services in many developing countries (Alex et al., 2002; Rusike and Dimes, 2004). In the past, extension services financed by public sector (Axinn and Thorat, 1972; Lees, 1990; Swanson et al., 1997) were a key component of the Green Revolution. Today, two out of three farmers in Africa, particularly small-scale farmers and women farmers (FAO, 1990), have no contact with extension services, and worldwide publicly funded extension services are in decline. Critics of public extension claim that its services need to be reoriented, redirected and revitalized (Rivera and Cary, 1997) as the poor efficiency of traditional extension systems has undermined interest in them (Anderson et al., 2004).

Both public and private delivery services can provide agricultural extension for modern farming.

There is a trend towards the privatization of extension organizations, often as parastatal or quasi-governmental agencies, with farmers asked to pay for services previously received free (FAO, 1995; FAO, 2000a; Rivera et al., 2000). This trend is stronger in the North than the South (Jones, 1990; FAO, 1995). Inclusion of the private sector can ensure competition and increase the efficiency of agricultural service delivery, especially with regard to agricultural inputsupply firms (Davidson et al., 2001). However, problems exist in terms of incentives and stakeholder roles. In Southern Africa, private sector led development showed that private firms have significant potential to improve small-scale crop management practices and productivity by supplying farmers with new cultivars, nutrients, farm equipment, information, capital, and other services. However, market, institutional, government, and policy failures currently limit expanded private sector participation (Rusike and Dimes, 2004).

The participation of a broad range of information providers on agricultural technologies, policies and markets, has been shown to play an important role in sustainable agricultural development.

Currently, countries in Africa are searching for participatory, pluralistic, decentralized approaches to service provision for small-scale farmers. The private sector, civil society organizations and national and international NGOs are increasingly active in agricultural research and development (Rivera and Alex, 2004), supporting local systems that enhance the capacity to innovate and apply knowledge. In the poorest regions, NGOs have strengthened their extension activities with poor farmers by using participatory approaches and developing initiatives to empower farmer organizations (Faure and Kleene, 2004).

Community based participatory learning processes and farmer field schools (FFS) have been effective in enhancing skills and bringing about changes in practice.

Agricultural extension and learning practitioners are increasingly interested in informal and community based participatory learning for change (Kilpatrick et al., 1999; Gautam, 2000; Feder et al., 2003). Group learning and interaction play an important role in changing farmer attitudes and increases the probability of a change in practice (AGRITEX, 1998) by recognizing that farming is a social activity, which does not take place in a social or cultural vacuum (Dunn, 2000). In Kamuli district in Uganda, a program to strengthen farmers' capacity to learn from each other, using participatory methods and a livelihoods approach, found that farmer group households increased their production and variety of foods, reduced food insecurity and the number of food insecure months and improved nutritional status (Mazur et al., 2006; Sseguya and Masinde, 2006).

     Farmer field schools (FFS) have been an important methodological advance to facilitate learning and technology dissemination (Braun et al., 2000; Thiele et al., 2001; van den Berg, 2003). Developed in response to overuse of insecticides in Asia rice farming systems, they have become widely promoted elsewhere (Asiabaka, 2002). In FFS, groups of farmers explore a specific locally relevant topic through practical field-based learning and experimentation over a cropping season. Assessments of the impacts of farmer field schools have generally been positive, depending on the assumptions driving the assessment. FFS have significantly reduced pesticide use in rice in Indonesia, Vietnam, Bangladesh, Thailand, and Sri Lanka (where FFS farmers used 81% fewer insecticide applications), and in cotton in Asia (a 31% increase in income the year after training, from better yields and lower pesticide expenditure) (Van den Berg et al., 2002; Tripp et al., 2005). Opinions on positive impacts are not unanimous (Feder et al., 2004). Farmer field schools have been criticized for their limited coverage and difficulty in scaling up; the lack of wider sharing of learning, their cost in relation to impact (Feder et al., 2004), the lack of financial sustainability (Quizon et al., 2001; Okoth et al., 2003), the demands on farmers' time and the failure to develop enduring farmer organizations (Thirtle et al., 2003; Tripp et al., 2005; Van Mele et al., 2005). However, there are few alternative models for advancing farmers' understanding and ability to apply complex knowledge intensive technologies. There is potential for FFS to self-finance in some cases (Okoth et al., 2003). FFS can stimulate further group formation (Simpson, 2001), but sharing local knowledge and sustaining relationships with different stakeholder groups post-FFS has often not been given sufficient attention (Braun et al., 2000).

International organizations are training community workers and promoting important participatory approaches to rural development.