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BRE 211: Principles of
Agriculture and Forestry
LECTURE 10
AGRO-FORESTRY
Definition

Land-use systems and technologies in which
woody perennials (trees, shrubs, palms,
bamboos etc) are managed on the same land
units as agricultural crops and/or animals.
 Is used to cover a variety of land uses that
combine tree growing, pasture and crop
production practices on the same piece of
land for the purposes of increasing or
improving the output of the soil.
Definition
 Aims
at increasing the overall
productivity of the land by combining
crops, animals and trees.
 Planting
of trees and shrubs is purposely
done in association with other farm
enterprises.
Implication of the Definition
 Agro-forestry:
 Involves
two or more species of plants
(or plants and animals) at least one of
which is a woody perennial.
 Has two or more outputs
 Always has a cycle of more than one
year.
Implication of the Definition
 Has
both ecological and economic
interactions between the different
components.
 Is more complex ecologically and
economically than a mono-cropping
system.
Benefits of Agro-forestry
 In
addition to enabling the farmer to
grow trees for various uses, keep
livestock and produce agricultural crops,
this system of land use has an
important role to play in
Benefits of Agro-forestry

A remedy to deforestation


Source of Income



Products from trees and shrubs can be sold for
cash.
Use of such products in the farm makes large
cash savings.
Increased Land Productivity


Provides a sustainable source of firewood thus
reducing deforestation.
When properly planned and managed, agroforestry increases the overall farm productivity
with little if any environmental damage.
Labour Saving

Availability of firewood on the farm releases the
labour of women for other farm activities.
Benefits of Agro-forestry

Soil and water conservation.

Trees





Protect the soil from strong winds, rains and
consequently reduce soil erosion.
Improve water retention of the soils.
Improve water catchment in an area
Enhanced Soil Fertility
 Enrich soil through leaf litter and nitrogen fixation.
 Stabilise the soil mantle by binding soil particles.
Aesthetic value
 All kinds of trees and shrubs help to beautify the
environment and make a place more pleasant to
live in.
Choice of species of trees/shrubs
 Following
factors should be considered
 Fast Growth ability
 Trees
that produce products (firewood,
fruits or timber) in a short time should be
selected
 Deep-rootedness
 Deep-rooted
ability
ensure minimum competition
for nutrients and moisture with crop plants
 They also resist drought
Choice of species of trees/shrubs
 Nitrogen
fixing ability
 Leguminous
plants that are capable of
fixing free nitrogen and converting it into a
form that is utilisable by plants.
 Their foliage is also rich in proteins for
animal feeding.
 Such plants are therefore good for soil
enrichment and feeding farm animals.
 It is preferable that such plants should be
palatable as fodder.
Choice of species of trees/shrubs
 By-product
 The
production
species should be good in the
production of timber, fruits, poles, honey
etc.
 Such trees or shrubs should produce these
by-products without harming or adversely
affecting other crops in the farm.
Agro-forestry systems

Three basic types:




Agro-silviculture (Crops and trees)
Silvo-pastoral (Pasture/animals and trees)
Agrosilvopastoral (crops Pasture/animals and
trees)
These systems give rise to different forms of
agro-forestry including:





Intercropping or Intensive Hedgerow
Wide Row Planting
Border Planting
Woodlot
Homestead Tree Planting
Forms of Agro-forestry systems
 The
form adopted largely depends on
land size, type of crops grown, land
topography in relation to soil
conservation and climate.
Intercropping/Intensive hedgerow

Rows of trees or shrubs are planted between
rows of crops.
 Preferrably leguminous shrubs (e.g.leucaena
and calliandra) are intercropped with crops
since they improve the soil.
 Intercropping can be done with maize, beans
or nappier grass as they would benefit most .
 Spacing largely depends on the crop with
which it is intercropped.
Management Stages

Management of intercropping includes:
 Establishment:



Seedlings used for fast growth.
The care of weeding, fertilizer application and
protection from animals the seedlings get as
the farmer tends to his crop plant enables the
seedlings to grow fast.
The first cutting of the shrubs should not be
done until they are 3 to 4 metres high.
Stages of Intercropping

Coppicing:

This is the cutting of the shrubs at the
beginning of the cropping season in order to
reduce competition for water, mineral nutrients
and sunlight.



The shrubs are cut down to 0.5 metres above the
ground.
During the growing season the shrubs are kept
down by the removal of shoots during weeding
operations.
After the last weeding the bushes are allowed
to grow since they will have little effect on the
crop plants.
Stages of Intercropping
 Growth
 When
there are no crops in the field,
especially during the dry season, the
shrubs should be allowed to grow tall.
 This encourages the production of
woodfuel and fodder and protects the soil.
 During this period, the green seed pods
produced should be removed and fed to
animals, as they are very rich in protein
content.
Wide Row Planting

Trees and shrubs are planted in wide rows of
between 8 and 10 metres from row to row and
up to 4 metres between trees
 Aims at wood and tree products such as
poles, timber and fruits unlike the intensive
hedgerow form, which aims at fuelwood.
 This necessitates that the trees grow
unchecked with only limited canopy
management to reduce shade on crop plants.
 The trees grow tall due to unchecked growth
making it necessary to space the trees widely
to facilitate the growth of crop plants.
Wide Row Planting

The trees must always be planted in rows
running from East to West to reduce the
shading effect on the crop plants.
 Although trees in this form of agroforestry may not improve crop yields, the
benefits gained from the sale of their
products and by-products often outweigh
the losses incurred.
 However, when it is practised with
pasture, the pasture does well due to
water retention and soil improvement
effects of the trees.
Wide Row Planting

Species of trees used in this form of
agro-forestry include:



Fruit and nut trees such as coconut,
cashew nut, mango, avocado and pear
trees.
Wood and timber production trees
including Grevillea, whistling pine
(casuarina equisetifolia) African
Blackwood, Muhugu, Acacia, Fig etc.
When animals graze under the trees
they control weeds without damaging
the fruits.
Border Planting

This is planting of trees, shrubs or
hedges on the farm. Such trees, shrubs
and hedges are used to:





Protect the farm as a fence
Mark boundaries
Windbreakers to protect crops
Provide wood and timber for fuel and
building as well as for sale.
Suitable trees for this system include
Eucalyptus, Makhania, Jacaranda and
Grevillea.
Woodlots
 These
are plots of land set aside for
trees only, usually on the parts of the
farm that are not productive or where
other forms of agricultural production
would encourage soil erosion.
 Trees for woodlots should be fast
growing species such as Acacia and
Eucalyptus.
 They produce large volumes of wood
fuel, timber, poles and fodder.
Homestead tree planting

Generally trees around the house are
planted for beauty and shade.
 However they can yield fruits, wood or
timber for the farmer.
 They should, however, not be planted too
close to the house to avoid their roots
damaging the house, or in the event of a tree
falling.
 Where the necessary care has been taken,
many tree species, including fruit trees are
suitable for homestead planting.
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