The need for diagnostic studies. Over the past decade, there has been an
excessive emphasis on rapid appraisal techniques to understand priority roles
for agroforestry in farming systems. The commonly used rapid appraisal
methods, such as "diagnosis and design," were intended only as a starting
point for researchers to forge a common understanding of a system's problems,
and identify priority topics requiring more in-depth diagnostic research
[Raintree, 1987; Scherr, 1990a; Miiller and Scherr, 1990]. The need for
continuous "re-diagnosis and re-design" to take account of subsequent
research was emphasised in principle. In practice, an initial rapid appraisal
has often become the basis of an entire programme of experimental research
("diagnosis and disappear"). The diagnostic analysis may not be re-evaluated
until the first on-farm trials (begun years too late) reveal lack of farmer
interest in technologies being studied.
Our current understanding of the role of agroforestry in land use is too
underdeveloped to be trusted to rapid appraisal. Researchers need to understand
farmers' strategies in establishing and managing existing agroforestry
systems. Farmer surveys have not been found especially reliable for this
purpose. Researchers will often need to work together with farmers in
exploratory or "diagnostic" trials with new components, sites, configurations
or management systems, to determine jointly which are suitable for further
research effort. Examples of this approach are discussed in Atta-Krah
[1987], Sumberg and Okali [1989], and Raintree and Hoskins [1988]. Several
years of on-farm diagnostic research may be needed before investment in
long-term formal experiments can be justified, or the specifics of experimental
design, such as selection of treatment factors, non-treatment factors,
control plots, and assessment criteria, appropriately selected.