crop records maintained in collaboration with the farmers.

Check Plots

 At each location (farm) there must be a means for
comparing the new technology with that of the farmer.
This may come from a check plot or from sampling the
farmer's yield. Both of these methods have advantages and
disadvantages. One of the main advantages of the check
plot is that it is identified ahead of time on a
representative part of the farm, and it can be harvested
at the same time as the treatment plot or plots. When a



 PRACTICAL FIELD ADVICE

 Farmers may treat identified check plots
 differently from their own fields for a couple of
 reasons.
 1) They usually know how to produce more than
 they do produce and want to prove this to the
 researcher. The reason they do not produce more
 on their own fields should be investigated.
 Results will usually reflect constraints that are
 imposed on a whole farm but that can be relaxed on
 a single small plot. The tendency to prove
 something to the researchers is reduced as
 confidence builds between researchers and farmers.
 2) Because check plots are part of the "trial,"
 farmers may wait until researchers tell them
 something needs to be done before doing it and not
 do it at the same time they do their own fields.
 Good communication between researcher and farmer
 reduces this problem.
 The first case results in higher yields in
 the check plot than on the farmers' own fields.
 The second case results in lower yields on the
 check plot. Both kinds of error have been
 observed.



sampling procedure is used, it may slow harvest because
sample sites must be harvested prior to the regular
harvest of the farmer. If delays are encountered, the