Farmers retained soil erosion knowledge and often mentioned
tree height as the factor in increasing raindrop size. In addition
farmers stated that keeping Cordia alliodora (a common timber
tree) in sloped fields could increase soil erosion, whereas in contrast
trees with an extensive root system could decrease erosion.
The farmers’ knowledge regarding coffee phenology is shown in
Fig. 1. General processes of shade and biophysical interactions related
to coffee phenology were well understood by farmers, who
knew all the stages proposed in the conceptual model and even
proposed new processes not reported in the literature (represented
by dotted nodes in Fig. 1). For farmers, flower formation timing
influences fruit size. The first flowers formed are larger and produce
larger fruits. This could illustrate a source/sink link well
known by plant physiologists: the first flowers formed after the
end of the vegetative phase would have more carbon available
for their development, hence for fruit growth (Franck et al., 2006).
Another key element for all knowledge sources was the scattering
of flowering over time; this was considered a process that affects
the amount of floral buds (according to processors and
farmers) or flowers (according to farmers). It was expressed in a
number of ways, such as ‘crazy flowering, frequency of flowering’,
meaning the undesirable effect of having a longer harvest season
due to scattered rains during flowering and a strong dry period,
which helps with a strong and grouped flowering (daMatta,
2004). There were other areas of knowledge unique to the literature
and not mentioned by farmers (e.g. initiation and induction
processes), but general processes (falling, fruit formation, ripening)
were well understood by all knowledge sources. The comparison of
farmers’ knowledge with knowledge exclusive to other stakeholders
in the coffee value chain did not provide expected information
difference. Processors were more knowledgeable on coffee quality,
but they did not relate this quality to field conditions. Interviews
with technicians provided very little information. Almost all the
knowledge showed by technicians was similar to the knowledge
possessed by farmers. This could be due to a bias in the interview,
whereby technicians felt ‘like they were passing an exam’, and thus
mainly presented the knowledge they had from literature rather
than presenting their own observations and experiences.
3.3. Farmers’ knowledge regarding biodiversity within the coffee farms
Coffee farmers identified the usefulness of each tree species
present in their farm in regards to small mammal and bird diversity
conservation and the type of resource each tree provides
(Fig. 2). Coffee farmers were knowledgeable on bird and mammal
behaviour in relation to the trees in their farms, such as feeding
patterns and habitat preferences for nesting or protection. Some
tree species were considered bad for biodiversity conservation;
for example Pinus oocarpa and Eucalyptus deglupta were mentioned
as trees with potential to reduce the presence of animals. The
reason why they were considered detrimental for biodiversity is
not clear; however, both species were exotic and classed as ‘hot’.
Farmers mentioned that birds or mammals are not using the exotic
species for nesting because the local fauna were not adapted to
these species. This detrimental effect was attributed to the ‘hotness’
classification, while the local fauna were seeking ‘fresh’ environments.
The lack of edible fruits for animals was also mentioned
as a negative characteristic of these species. On the other hand, E.
poeppigiana was the species most mentioned by farmers as being
useful for many faunal species. However, the great dominance of
E. poeppigiana in the coffee agroforestry systems within the study
area probably increased the positive perception that farmers have
of this species. Moreover, even when E. poeppigiana was considered
beneficial for the resources given to birds and mammals, farmers
recognize that if trees are frequently pruned the benefits for biodiversity
will be considerably diminished.
3.4. Coffee farmers’ water balance knowledge
The diagramming capabilities of AKT combined with farmers’
knowledge were utilised to build a conceptual model of the effects
of tree presence on water in coffee plantations (Fig. 3). The maintenance
of an appropriate level of humidity for optimum growth
of coffee was an important aspect of shade tree management,
and farmers explained that at different times of year more or less
soil water content is needed according to the coffee phenology.
Tree canopies played an important role in water conservation,
as they are the medium through which sun and rainfall are filtered.
Farmers considered rainfall interception by the tree canopy as beneficial.
The ensuing decrease in the amount of rainfall reaching soil
directly was mentioned as a form of regulation of water input into
the system. Farmers showed an understanding of water resources
protection in regards to which tree species were the most effective
at protecting water resources and therefore should be kept close to
a water source; e.g. Zygia longifolia is considered beneficial because
its roots protect against erosion near water sources, whereas E. deglupta’s
high water consumption will dry out a water source and is
considered detrimental to that source. Farmers in general were
careful and tended not to disturb the natural species composition
around these areas to prevent a possible decrease in water supply.
There were some knowledge differences between organic and
conventional farmers. For instance, organic farmers frequently
mentioned in their discourse the importance of water provision
for human consumption, as well as how water could be polluted
through the utilisation of chemical inputs. Similarly, the management
of soil moisture balance due to the litter and soil organic
matter was mentioned by a higher number of organic farmers than
conventional ones. There was a general concern among all the
farmers on soil and water conservation and not using chemical inputs.
Both organic and conventional farmers were concerned about