- What
is agroforestry?
- Why
agroforestry?
- What
can we get from agroforestry?
- What makes
a good agroforestry system?
- How is agroforestry
practiced in the Philippines?
- What is
next for agroforestry?
What
is agroforestry?
Agroforestry is a land-use management
system that combines the production of trees with agricultural
crops, animals and/or other resources in the same area. It aims
to increase or sustain productivity while maintaining ecological
stability. It also hopes to increase income for improved quality
of life.
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Why agroforestry?
Nature provides us with what
we need and we must be responsible in taking care of it. But
with the growing population, upland resources are being threatened.
People migrating to the uplands brought with them diverse lowland
farming practices that are most often not applicable in the
uplands.
These circumstances greatly contribute
to the destruction of our upland resources--a situation, which
would also mean diminishing production, vanishing biodiversity,
continous soil erosion, flashfloods and other problems.
As one of the alternative farming
systems, agroforestry improves these lowland-farming practices
making it more appropriate in the uplands.
Agroforestry integrates the two
major disciplines of utilizing and managin the land--agriculture
and forestry. Through agroforestry, you can utilize your farm
into various combinations of food crops, trees, animals and
other resources. Integrated production systems and soil and
water conservation measures are adopted to efficiently increase
food production while maintaining soil fertility and improving
its physicochemical and biological properties.
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What can
we get from agroforestry?
Agroforestry promotes self-sufficiency.
You can optimize land use to increase production and satisfy
needs. Trees and other plants supply life-giving oxygen and
help purify the air. They also sequester carbon by absorbing
CO2 from the atmosphere and incorporate them in their biomass.
Trees also provide us with firewood,
raw materials for construction and other needs. Moreover, trees
can serve as barriers for protecting food crops against soil
erosion and destructive wind; and provide fodder to animals
and materials for organic fertilizer. Animal wastes could be
used as fertilizer while food crops provide for subsistence
and cash needs. Good interaction among these components serves
as the primary step to attaining agroforestry's twin goal of
production and protection.
Ecologically, agroforestry helps
rehabilitate and preserve the environment through soil and water
conservation in sloping lands. Tree roots hold the soil together
thus minimizing erosion and eventually the occurrence of floods
during rainy season. Tree canopies also help conserve the soil
from the erosive impact of raindrops. It does not only intercept
large amount of rainfall but also lare amount of incoming radiation
depending on the percent of canopy coverage, leaf structure
and crown stratification. The leaf litter and humus built up
under the tree stands control flow of water and allow them to
percolate into the soil.
While contributing to conservation
strategies, trees also serve as "nutrient pumps" and
improve soil fertility. Nitrogen-fixing trees are able to fix
nitrogen gas from the atmposphere and convert them to ammonia.
These nutrients are then returned to the soil through the litter
fall or when the prunings are applied as mulch or green manure
(organic fertilizer).
During decomposition, the prunings
release the nutrients and increase organic matter in the soil
thereby improving soil fertility, soil structure, infiltration
and moisture-holding capacity.
Efficient utilization of water
and nutrients in the soil profile is achieved by intercropping
deep-rooted crops with shallow-rooted species. This enables
the trees to minimize competition for water and nutrients far
below the soil surface.
All the protective and ameliorative
roles of agroforestry discussed could result to long-term benefits
particularly the overall improvement of the socio-economic conditions
of the subsistence upland farmers. As the upland ecosystem is
properly conserved through agroforestry, it follows that improved
productivity would be sustainbed through time. The stable production
of goods and services, in turn, ensures self-sufficiency in
food, fuel, fodder and other necessities. The extra income could
also be used for other social benefits such as clothing, shelter,
medical care and education of their children. All of these can
contribute to the general improvement in the quality of life
of the farmers.
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What makes
a good agroforestry system?
To attain the desired objectives,
an output criteria must be set. The following are the criteria
used by the International Centre for Research in Agroforestry
(ICRAF) for a sound or well-designed agroforestry system:
1. Agroforestry
systems should be productive
- Generates direct benefits
such as food, fodder, feed for fish and livestock, fuel, polewood/wood,
other products such as gums, resins, latex, oil, herbal medicine,
etc.
- Produces indirect benefits
or "service roles" such as soil and water conservation,
fertility improvement, microclimate amelioration, live fencing,
etc.
- Increases income
2. Agroforestry
system should be sustainable
- Employs soil and water conservation
strategies to ensure long-term productivity
- Can withstand sudden changes
in weather, epidemic and market prices
- Requires putting some forms
of incentives into the technology to ensure adoption of conservation
practices especially those who are operating close to the
margin of subsistence
3. Agroforestry
system should be easily adopted and socially acceptable
- Technologies should be culturally
acceptable and easily adoptable
- Directly involves the farmers
in the planning and designing of agroforestry systems to ensure
adoption
- Consistent with technical,
financial and manpower capabilities of the local people/target
clients
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]
How is agroforestry
practiced in the Philippines?
Although agroforestry is being
practiced since time immemorial, it was only during the last
three decades that agroforestry was recognized as a field of
study. To further develop and promote it into a scientific discipline,
existing agroforestry practices were documented. Based on the
classification made by ICRAF, the different forms of agroforestry
can be classified based on components being mixed, dominant
role of the tree component, and interactions between or among
the components in time and space.
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]
Agrisilvicultural
system
This system is the simultaneous
production of agricultural crops and trees exhibited through the
following forms:
- Alley cropping system
Also known as hedgerow intercropping
system, the alley cropping system is most often practiced in
gently to moderately sloping areas. It involves the planting
of leguminous trees or shrubs as hedgerows along contours. Aside
from serving as physical barriers against soil erosion the hedgerows
provide beneficial effects on the associated crops. The leaves
can be pruned for organic fertilizer, used as fodder for livestock,
or serve as mulch to control moisture loss.
However, trees compete for sunlight,
space, water and nutrient uptake of the food crops. Hence, trees
could withstand frequent pruning are used to allow greater light
penetration for the crops planted along the alleys. Deep-rooted
trees are also preferred to minimize competition for water and
nutrients in the soil. Nitrogen-fixing trees or shrubs are also
preferred as hedgerows.
This system is also locally best
exemplified by the Sloping Agricultural Land Technology (SALT
1) developed by the Mindanao Baptist Rural Life Center (MBRLC)
in Bansalan, Davao del Sur.
2.
Multistorey system
This sytem comprises the production
of mixed species of trees and food crops occupying different
canopy levels. Trees and shrubs often occupy the upper layer
while the lower layer is made up of shade-tolerant crops like
banana, coffee, pineapple and others.
Series of canopy layers protect
the soil against the erosive impact of rainfall thereby reducing
soil erosion and surface run-off. However, the upper layer of
tree canopy reduces light penetration for the crops underneath.
Thus, shade-tolerant crops are grown underneath and branch pruning
or thinning of overstorey trees are applied when necessary.
3.
Improved fallow system
In this system, one area is cultivated
while another area is allowed to rest or fallow. Fallowing enables
the soil to rejuvenate. After some time, the fallowed area is
used again for production while the previously cultivated land
is allowed to rest.
To shorten fallow period, nitrogen-fixing
trees like ipil-ipil (Leucaena leucocephala) are planted
in the area. Its leaves and branches are then pruned and returned
to the soil as fertilizer.
Other nitrogen-fixing plants
(e.g. peanuts, etc.) may also be planted together with the nitrogen-fixing
trees. This practice allows faster soil rejuvenation (e.g. 5
to 6 years) from the traditional rest period of ten to eleven
years. With leguminous trees, and other nitrogen-fixing plants,
soil is enriched with nutrients thus shortening the rest period
to six years only. The Naalad farming in Naga, Cebu clearly
demonstrates this improved fallow system.
4.
Taungya system
Newly planted trees are interplanted
with food crops in the taungya system. However, as soon as the
tree canopies close, intercropping is no longer possible. Hence,
farmers transfer to another new forestation area to repeat the
process of taungya.
This system is a cost-effective
way of reforestation. However, it limits the farmers' opportunity
to sustaine food production and income in a certain area. Permanent
crops cannot be grown since farmers have to leave the place
as soon as the tree canopies close. Thus, to prolong intercropping,
thinning and/or branch prunings of the trees may have to be
applied. Alternatively, shade-tolerant crops have to be underplanted.
5.
Rice terraces-forest coupled agroforestry system
This system is clearly demonstrated
in the famous Banawe Rice Terraces in Ifugao. Bench terraces
are constructed along steep mountain sides for the planting
of rice throughout the year. The outer edges of the terrace
benches are established with bunds to contain the water for
irrigating the rice. Holes are constructed along the bunds to
drain excess water. Hence, terraces below are saved from being
washed away.
The forest stands where water
springs originate are protected to irrigate the rice planted
on the terrace benches. The famous rice terrace with protected
forests in Banawe, Ifugao serves as the best example of this
system. Its existence for more than 2000 years indeed proves
of the sustainability of the system.
6.
Trees as boundary markers, live hedges, windbreaks and as live
trellis
In the agrisilvicultural system,
trees are also planted along the farm boundaries either as boundary
markers, live fenc/posts, and/or windbreaks/shelterbelts. Trees
can also be used as live trellis for climbing crops.
7.
Silvipastoral system
This system integrates the production
of woody perennials with livestock production. The Silvipastoral
system can be in the following forms:
a. Tree-crop
grazing system
Cattle, goats, sheep and other
animals are allowed to graze freely in between the large trees
in the relatively mature tree plantations of the tree-crop grazing
system. This sytem may also be adopted in coconut plantations
provided that the dungs of large ruminants are regularly collected.
Collection should be done because dungs serve as breeding areas
of rhinoceros beetles which are pests of coconut.
b. Protein bank system
This involves the intensive planting
of fodder trees/shrubs and pasture grasses on a small plot.
Leguminous fodder trees or shrubs (e.g. ipil-ipil, kakawate,
Desmodium, etc.) serve as supplementary source of protein
for livestock. In this system, the fodder trees or shrubs may
be established as small plots on certain portions of the farm
or pasture areas. These areas are planted intensively for maximum
fodder production. The areas are also fenced off and regularly
pruned. The top and branch prunings are fed to the animals through
the "cut and carry" system.
c. Live fence system
Trees can serve as fence by growing
rows of palatable trees or shrubs around a certain grassland
area enclosing the grazing animals inside. Aside from the trees'
role as fence, they can be managed (e.g. regular top pruning
to encourage more lateral branching) such that the enclosed
animals can browse on the low-lying branches serving as fodder
supplement.
d. Agrisilvipastoral
system
This system is characterized
by the simultaneous production of agricultural crops, trees
and livestock in the same unit of land. This system can be in
the following form:
- agrisilvicultural system converted
to silvipastoral systems
- multistorey system with free
grazing
- alley cropping system using
pasture grasses/fodder crops and agricultural crops as alley
crops like the goat-based Simple Agro-Livestock Technology
(SALT 2) developed by MBRLC
e. Agroforestry
integrated with other production systems
In some cases, agroforestry is
integrated with other production systems:
f.
Agroforestry-tree plantation integrated production systems
The Sustainable Agroforest Land
Technology (SALT 3) model of MBRLC exemplifies this. In this
system, the upper 60% of the hillside are devoted to small-scale
reforestation using one or more forest tree species for various
end-uses (e.g. sawntimber, polewood and/or fuelwood). When the
trees are already tall, there is also that option of interplanting
rattan (cane). On the other hand, the lower 40% are devoted
to food production where alley cropping systems or SALT 1 is
practiced.
8.
Agroforestry-Aquaculture-Livestock integrated
production system
This system is extensively being
practiced in China and is now being started in the Philippines.
The system excavates lands near irrigation canals for conversion
to fishponds. The soils excavated were used for constructing
fishpond dikes and landfills for agroforestry crops.
Trees are planted in eight meter-intervals
to serve as live end poles for the trellis of grapes and other
climbing crops. Both sides of the dikes are also planted with
sweet potato and used as food supplement for pigs.
The pigs' wastes from the pens
are then channeled directly to the ponds to serve as fertilizer
for the phytoplanktons. They serve as food for the fish being
cultivated. The ponds are regularly excavated and the silt is
used as fertilizer for the agroforestry crops.
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What is
next for agroforestry?
Agroforestry farms are indeed
unique depending on the existing biophysical and socio-economic
conditions of the area. There are even several forms to choose
from and flexible enough to be modified for the upland and even
the lowland areas.
As the agroforestry farms vary,
more scientific researches need to be conducted to address the
problems and needs of the upland farmers. The greater the ecological
and economic problems in the uplands, the more we need to pursue
agroforestry studies and researches.
There will always be threats,
problems and challenges. But with the combined efforts and utmost
cooperation of farmers, extension workers and researchers, the
twin problems of poverty and environmental degradation will
surely be attained through agroforestry.
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Source:
Ramos, G., 2000. A Primer,
Securing the Future: by promoting the adoption of sustainable
agroforestry technologies, In R. Dalmacio and N. Lawas (eds),
Institute of Agroforestry, University of the Philippines at Los
Banos, Laguna.
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