The possibilities and productivity of farmer participation will be conditioned by the situation in which water users find themselves. The incentives and constraints they face derive from many sources, but three broad categories of factors appear most important:

(a) historical factors that affect farmers' willingness and ability to assume responsibility for various irrigation tasks,

(b) physical and economic factors that shape the supply of and demand for water, thereby affecting water users' orientation toward collective action, and

(c) socio-cultured and political factors that influence the way water users relate to one another and to the government.

Each of these areas could be analyzed in a chapter by itself, but it will suffice to review some of the effects which context can have on the nature and extent of farmer participation for irrigation management. This should help to guard against sweeping generalizations or uniform policy pronouncements that ignore contextual differences.