Knowledge, science, and practice in ecological weed management: farmer–extensionist–scientist interactions - Ecological Management of Agricultural Weeds - page 130

and lowering production costs requires farmer management of heterogene-
ous conditions.
In the early 1990s, integrated pest management (IPM) specialists from the
Center for Teaching and Research in Tropical Agriculture (CATIE) began a
program in Nicaragua to improve pest management in coffee (Staver et al .,
1995; Staver, 1998). In parallel with field studies of pest dynamics and repli-
cated trials with new management practices, the team began work with
groups of smallholder coffee growers. The team quickly found that growers
had extensive practical experience, but had an incomplete understanding of
pests and the reasons for their variability. Farmers were also uncertain about
when to use specific practices and how to evaluate whether one practice was
better than another. These difficulties limited their efforts to test and adapt
alternative management options.
To improve grower capacity to evaluate practices and make decisions based
on observation and ecological reasoning, the CATIE team has been using par-
ticipatory training procedures. Farmer groups meet every six to eight weeks
during the yearly crop cycle to discuss what they know about pests, how they
decide to manage them, and to fill in gaps in their understanding with practi-
cal exercises. A nearby coffee field is used as a laboratory to observe pests and
their variability and to learn scouting methods. Between sessions farmers
analyze their own fields and bring results to the next meeting.Data variability
among farmers, fields, and seasons is used to promote discussion on why pest
populations fluctuate, the effectiveness of current practices, and the relation-
ship between pest levels and control decisions.In this process farmers begin to
develop their own ecological logic of how to manage pests better and become
eager to test alternative practices in a group plot or in their own fields.
In the case of weeds, the participatory training takes into account farmer
knowledge of weed types. In a quick walk through a nearby coffee field,
farmers choose a weed they consider very damaging to coffee, one not so dam-
aging,and one that does not affect coffee plants.With these weeds in hand,the
group discusses the different species one by one, how they grow and repro-
duce, and what type of damage they do to coffee plants. Individual weeds are
grouped into categories by growth habit. The group also analyzes other
ground covers in the coffee field such as leaf litter, discusses the consequences
of bare soil, and identifies the weeds and other ground covers that protect the
soil without competing much with coffee. To measure the cover of each weed
type in the field, the group uses a simple transect method, and analyzes how
the current control practices favor certain weeds and reduce others. Finally,
the group discusses the best combinations of ground cover and identifies
practices to implement in their comparison plot. Progress is evaluated in