Cocoa-Based Agroforestry Production Systems
Eduardo Somarriba and John Beer
Historical Account: Cocoa in Talamanca and Bocas Del Toro
- Cocoa was probably used by local amerindians before Spaniards
attempted to settle in the Colonial Talamanca region (which
then included Bocas del Toro).
- Cocoa was produced, and traded, during colonial times in
Spanish settlements in the Talamanca Region. However, agricultural
settlement never lasted in the area due to inter-tribal wars,
disputes among colonial authorities, and rebellions against
Spanish ruling.
- Major agricultural development started in 1860's with the
commercial production of bananas.
- Cocoa commercial plantations were established to replace
banana plantations decimated by banana's Panama disease (Fusarium
oxysporum). Cocoa plantations peaked in 1920's.
- Banana production ended in 1934 and moved to the Pacific
Region of Costa Rica and Panama. Cocoa was the most important
commercial crop between 1940-1970. Banana production was re-inititated
in 1978 with new varieties resistant to Panama disease. Cocoa
plantations were converted to banana in the lowlands; most cocoa
is now produced in hilly areas.
- Cocoa prices peaked in 1977-1978, but monilia (Moniliophthora
roreri) appeared in 1979 and production dropped to nearly
zero. Cocoa prices went down in 1980 and remained low until
1993. Prices have increased between 1994-1998, from less than
1 US$/kg to around 1.6 US$/kg. Management levels of cocoa plantations
depend on price levels.
- Cocoa production was promoted between 1982-1987 in both Costa
Rica (Talamanca) and Panama (Bocas del Toro) using allegedly
more productive genotypes. The CATIE-GTZ-INRENARE agroforestry
project started operations in 1986; shade management in cocoa
plantations was identified as a major research line.
Cocoa-Based Agroforestry Systems Researched In Talamanca And Bocas Del Toro
Research design in 1986/1987 attempted to address several farm
scenarios with cocoa as the main crop: 1) farmers in fertile,
lowlands interested in establishing new, well managed cocoa plantations
(cocoa production only, Talamanca); 2) some farmers were interested
in establishing new, well managed plantations combining cocoa
and timber production (Bocas del Toro); 3) shade regulation in
existing farms as a means to increase cocoa production required
replacing un-productive, un-regulated shade by a new, productive,
easy to manage shade canopy; some farmers were willing to concentrate
only on cocoa, others were interested in both cocoa and timber
production; and 4) plantain was introduced in 1981 and became
the major economic alternative for farms located in lowlands,
close to the local markets; diversified systems combining cocoa
and plantain can be attractive to them.
Five cacao-based agroforestry systems were selected for research:
1) leguminous tree species (Gliricidia sepium, Erythrina poeppigiana
or Inga edulis) used as mono-specific shade in new
cocoa plantations; 2) timber tree species (Cordia alliodora,
Terminalia ivorensis or Tabebuia rosea) used as mono-specific
shade in new cocoa plantations; 3) leguminous trees for shade
conversion in existing cocoa plantations; 4) timber species (same
as above) for shade conversion in existing cocoa plantations;
and 5) cocoa-plantain-timber systems for intensive production.
Experiments of each type were established in private farms in
collaboration with farmers. Research included: three farms of
type 1 experiments, two farms of type 2, two farms of type 3,
five farms of type 4, and two farms of type 5. In each farm, treatments
(shade species) were replicated 3-4 times; each experiment covered
1-2 ha. Research was initiated in 1989-1990 and all experiments
were monitored between 1989-1995. From 1995 to present only one
experiment of types 1,2, and 5 are monitored; four farms with
type 4 experiments are presently monitored. Preliminary results
have been published (see reference list). In what follows we summarize
results from research conducted in Turrialba, Talamanca and Bocas
del Toro.
What We Know
- Differential management (pruning or thinning) of radically
different shade species (service or timber producing) can result
in similar cocoa production.
- In soils with medium to high natural fertility levels and
with moderate chemical inputs, differential management favors
the use of timber species over the traditional service, leguminous
species when standard financial analyses are used.
- Crop losses due to fungal pathogens were not affected by the
selection and management of the shade species nor of the cocoa
genotypes (a total of 12 interclonal crosses from the cocoa
colection of CATIE, Turrialba, Costa Rica). Loss due to pathogens
are determined only by cultural practices in nearby farms, which
determines the availability of sources of innoculum. Losses
levels varied between 35-75% depending on the local context
of the experiment. In a given location, losses were similar
between shade species and between cocoa genotypes.
- Major differences in cocoa production are determined by the
selection of the genotype. Adjusting losses to a zero level
(which gives an idea of the productive potential of the genotype),
cocoa production per genotype varied between 700-2400 kg/ha/yr
of dry cocoa beans under identical conditions.
- Even larger variability in cocoa yields are observed at the
plant level, opening the possibility for the selection and vegetative
reproduction of highly productive genotypes. A large majority
of the cocoa plants produce less than 1 kg/plant/yr, thus limiting
yields.
- Pathogens are still an unresolved problem in cocoa production
in Talamanca and Bocas del Toro, specially, monilia. Witches-broom
(Crinipelis perniciosa) is a persistant threat. Pathogens
cause less harvestable production and more costs.
- Weed management is critical in newly established cocoa plantations.
The selection and management of the shade species can drastically
reduce this problem.
- Introducing either leguminous or timber species in existing
cocoa plantations is a simple and cheap alternative to replace
undesirable existing shade canopies.
- Timber growth is excellent in both new and existing cocoa
plantations in the study region. Timber trees benefit from the
medium to high natural soil fertility levels of sites where
cocoa in grown and year round water availability in the Talamanca
and Bocas del Toro region, Management of the cocoa (weed control,
fertilization, crown pruning, etc.) ameliorates from interspecific
competition at early eages, and low shade tree densities (70-280
trees/ha) delays intraspecific competition.
- The short rotation to produce commercial timber trees facilitates
the incorporation of small-medium farms in reforestation programmes.
Financial performance of most systems tested is satisfactory,
specially when labor is cheap. Plantain, timber trees and the
use of short term crops as temporary shade (in new cocoa plantations)
improves the financial performance of cocoa plantations.
- Soil organic material increases under shaded cocoa, even on
soils with high initial organic material content. Pruned leguminous
shade trees have a greater effect than unpruned timber trees.
- Cocoa production is primarily determined by light levels when
the same genetic material is compared. The response to improved
soil fertility is only realized when shade levels are managed
at relatively low levels (e.g. by tree pruning).
- Fine root growth of cocoa occurs at the beguining of the rainy
season while for many tropical trees, including C. alliodora
and E. poeppigiana, it occurs at the end of the rainy season.
- The use of leguminous shade trees, especially when they are
regularily pruned, accelerates nutrient cycling.
- Litter production and net primary productivity of shaded cocoa
plantations is similar to that of natural tropical forest and
is much greater than most tropical agricultural systems.
- C sequestering in shaded cocoa systems was 5 Mg/ha/yr over
10 years when sugar cane fields were converted to cocoa plantations.
- These systems can be sustainable with little and even no external
inputs (indicators: net primary productivity, soil organic material,
commercial production).
What We Think We Know
- Enough information is available on cocoa agronomy (shade requirements)
and silviculture to design sound simple cocoa-based agroforestry
production systems.
- Diversified systems perform financially better than cocoa
monocrops. Companion early crops must respond to local markets,
access roads, etc.
- Timber species can be combined with leguminous species to
ensure quick soil cover and reduce weed infestation, reduce
management costs and increase financial performance.
- There is plenty of room for improving cocoa production by
introducing pathogen resistant, high yielding genotypes. Clonal
materials seem more promising than sexual plants.
- Cocoa plantations are suitable for small farmers in remote
areas and buffer zones. Dried cocoa beans can be stored without
rotting, value per unit weight is high thus facilitating transport
to remote markets, forest-like structure enhances biodiversity
and smooths the gradient between protected areas and surrounding
agricultural areas.
- Tested genotypes are suitable for low shade levels (high yields).
The yield level — shade level — fertility level interaction
may predict that this is correct when natural soil fertility
is high (like in our study sites), when fertilizers are added,
or when both hold true.
- Increased organic material inputs improve nutrient availability
for trees and cocoa.
- The presence of the shade trees reduces nutrient leaching
from the system.
- The presence of mixed shade species accelerates litter decomposition
and hence nutrient cycling.
- How to manage a diverse shade canopy without reducing potential
cocoa yields.
What We Do Not Know
- Performance of high yielding clones under small farm scenarios,
with low chemical inputs and higher shade levels.
- Comparative advantages of using N-fixing and/or mulch producing
leguminous trees as shade over cocoa under low fertility soils
when chemical fertilizers are not available.
- More diverse shade canopies can be designed by adding fruit
species that satisfy the following criteria: a) good shade characteristics,
b) valuable for markets, home consumption or biodiversity maintenance,
c) produce nuts or non perishable fruits that can be stored
and profitably transported to distant markets.
- Damage levels to cocoa plants (and effects on cocoa yields)
during tree felling and timber extraction.
- Farmers rationale for shade canopy design and management.
- Shape of the interaction: yield-shade-fertility-costs.
- How to manage shade trees within an integrated pest management
programme in order to reduce pest/disease incidence and/or pesticide
applications.
- The effect of increased soil organic material on biodiversity
(e.g. soil flora and fauna).
- Whether it is preferable to have fast or slow decomposing
litter (e.g. is fast cycling of nutrients more important than
protection of the soil surface?).
- Economic (including externalities) contrasts of cocoa production
under mixed shade versus mono-specific shade strata.
- Management regimes for fruit trees to enhance yields (home
or commercial use) that also improve cocoa yields (e.g. pruning
regimes which have both objectives).
- How important are cocoa plantations in buffer zones as a means
of extending protected areas and whether biodiversity conserved
increases as a result.
- Effects of shade levels on cocoa (bean) quality.
- Effect of fast timber tree growth rates, when cultivated in
cocoa plantations, on timber quality.
Sustainability In Cocoa Production
- Minimizing environmental degradation
Shaded cocoa plantations provide good soil cover after the establishment
phase (soil erosion may not be a prevalent ecological problem
in most plantations), pesticides and fungicides are of limited
use in normal operations (toxic pollutants are not a critical
issue in cocoa producing areas), herbicides are regularily used,
inorganic fertilizers are seldom used in remote areas; intensive
cocoa cultivation requires 0.5-1.5 Mg/ha/yr. Typical fertilizer
amounts used in the experiments in Talamanca and Bocas del Toro:
500 kg/ha/yr of commercial formulations. Environmental degradation
can be minimized by: 1) managing ground cover (selection of
shade species, companion crops, plantation densities, planting
arrangements) to reduce weed infestation and the use of herbicides;
2) avoid intensive cultivation systems to reduce inorganic fertilizers;
and 3) choosing shade species that produce large quantities
of organic material (or by pruning regularly, force the trees
to do this).
- Maximizing biological diversity
Moderate cocoa yields (1 Mg/ha/yr) should be aimed at. Shade
levels in adult plantations must average 30%, with seasonal
variations between 20-50%. Tree canopies may include 100-150
trees/ha in adult plantations. Tree species must be selected
according to shading characteristics, productive outputs, and
environmental services required (e.g. perching sites for birds,
food for mammals, honey production, etc.). Diversification of
commercial components (species) should reduce the need to increase
cocoa yields by using more intensive management (e.g. agrochemicals).
Temporary crops add to biological diversity of the systems.
A narrow genetic base for cocoa is expected since only high-yielding
clones (a mixture of 7-10 clones) are recommended.
- Long-term yields
Matching shade canopies (shade levels, botanical composition,
pruning and thinning regimes) to site characteristics (fertility
levels, socioeconomic conditions of the farmer) and appropriate
cocoa genotypes can result in acceptable, long-term yields (cocoa,
timber, fruits, environmental services, etc.).
- Improved livelihoods of small-scale farmers
From the production side, adequately designed cocoa-based agroforestry
systems (above) con result in productive, ecologically sound
production systems. Prices, higher and less variable, need to
be improved to motivate farmers.
Recommendations
- Implement new, on-farm research on the ecological, financial,
agroforestry aspects of cacao-based agroforestry prototypes
in remote and buffer zone areas. A first draft of the prototype
is ready for further discussion and improvement. Project development
and funding should be addressed.
- Design and implement, researcher-controlled, on-farm experiments
focusing on the study of the shade-fertility-yield interaction
in cacao — based agroforestry systems.
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