new variety and a similar check plot with their usual
variety.
 FMTs can be designed to provide agronomic and
economic data for the researcher, but the trial process
must not interfere with the farmers' normal activities and
their ability to interpret results as they see them.
Because there is little control of variability, a large
number of farms across a region are required for
researchers to measure treatment effect. Regional
analysis will determine the level of stability of the new
technology and the degree of homogeneity of the
recommendation domain. It is important to recognize that
trials "lost" for purposes of researcher evaluation are
not necessarily lost for the purpose of farmer evaluation.
Farmers will decide on the merits of the alternatives
without drawing on the kind of technical data needed by
the researcher.
 Conducting an FMT is relatively easy because of its
simplicity. It has a reduced number of treatments
(sometimes just one), and usually has no replications.
The simplicity of FMTs makes it possible for other
institutions to play a role in the evaluation process in
the region. For example, being involved in on-farm
trials provides an opportunity for extension personnel to
become familiar with the technology. A major advantage of
this involvement is the establishment of stronger
institutional linkages, which can accelerate adoption of
newly developed technology.
 Recommendation domains are tentatively defined in the
initial characterization and are redefined or partitioned
during the research procedures described in previous
chapters. For purposes of the FMTs, only farmers who fall
within the specific recommendation domain for which the
alternatives were designed should be chosen to
participate.

DESIGN

 Because there are large numbers of farmers involved
in FMTs and because the trials are not managed by the
researcher, there is a limit to the number of measurements
the researcher, personally, will be able to make during
the trials. The most important, and usually the only one,
will be yield. Other information will be available from