BUSITEMA UNIVERSITY- ARAPAI CAMPUS

DEPARTMENT OF CROP PRODUCTION AND MANAGMENT

CERTIFICATE IN GENERAL AGRICULTURE
YEAR TWO SEMISTER TWO (2021/2022)

CGA2202: AGROFORESTRY AND BEE KEEPING (3 CU)

PART 1: AGROFORESTRY
INSTRUCTOR: Alibo Deborah
E-mail: debbieemukeu@gmail.com

TOPIC ONE: INTRODUCTION TO AGROFORESTRY

Agroforestry—the combination of agricultural practices with forestry practices has become
important for sustainable land-use in many parts of the world, although most clearly so in
tropical, developing countries. In these developing countries it is seen by many as a means of
mitigating land degradation and deforestation and alleviating poverty particularly for rural
communities. The scientific application is relatively new, although many of the practices are
ancient. However, trees sometimes have negative impacts. For example they can compete with
crops for moisture, or may interfere with farming operations, and some species have the potential
to become weeds. Such negative impacts can be avoided by careful agroforestry planning.

Definition
Agro-forestry is the intentional integration/combinations of trees into crop and animal farming
systems to create environmental, economic, and social benefits. It is an intensive land
management system that optimizes the benefits from the biological interactions created when
trees and/or shrubs are deliberately combined with crops and/or livestock. The main focus of
agroforestry is to meet the needs of rural people in developing countries in a sustainable manner.

For a management practice to be called agroforestry, it typically must satisfy the four "i"s: These
are referred to as the four key characteristics of agroforestry; they are the essence of agroforestry
and are what distinguish it from other farming or forestry practices. To be called agroforestry, a
land use practice must satisfy all of the following four criteria: Intentional, Intensive, Integrated,
and Interactive.

Intentional
Combinations of trees, crops and/or animals are intentionally/purposefully designed and
managed as a whole unit, rather than as individual elements/practices which may occur in close
proximity but are controlled or managed separately.

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Intensive
Agroforestry practices are intensively managed to maintain their productive and protective
functions. It often involves science based annual operations such as cultivation, fertilization,
pruning, trimming, irrigation and other cultural practices are planned in advance to compliment
reforestation, tree protection, market cycles and work load.

The Productive functions are: Food, fodder, fuel wood, cloths and shelter.
The Protective functions are: Wind breaks, soil and water conservation and soil improvement.

Interactive
Actively manipulate the biological and physical interactions between the tree, crop and animal
components. Forest management, pasture management and grazing management are conducted
in harmony so as to enhance the production of multiple harvestable components, while also
providing conservation benefits. The combination of the products realized usually exceeds the
normal yield of either enterprise individually. The goal is to enhance the production of more than
one harvestable component at a time, while also providing conservation benefits such as non-
point source water pollution control or wildlife habitat.

Integrated
The trees, livestock and forage are functionally combined into a single management unit tailored
to meet the landowner’s objectives. The tree, crop and animal components are structurally and
functionally combined into a single, integrated management unit. Integration may be horizontal
or vertical, and above- or below-ground. Such integration utilizes more of the productive
capacity of the land and helps to balance economic production with resource conservation. Thus,
agroforestry focuses on the integration of farming and trees on a property, whether that property
is a small home garden, a large estate or communally owned land.

This definition implies that;

 Agroforestry normally implies two or more species of plants (plants and animals)
 The cycle of an agroforestry system is always more than one year
 Even the simplest agroforestry system is more complex ecologically and economically
than a mono cropping system

Agroforestry aims at increasing;

 Productivity
 Sustainability
 Diversity

Productivity
Agroforestry can increase productivity in many ways;
 Improve yields of the associated crops
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  Reduction of cropping systems
 Increase labour efficiency
 Increase of the tree products

Sustainability
Agroforestry conserves the production potential of the resource base mainly through the
beneficial effects of woody perennials on soil. Agroforestry can achieve an indefinite
maintenance conservation and fertility goals.

The beneficial effects of woody perennials include;

 Improvement or maintenance of organic matter
 Soil erosion control
 Nutrient recycling

Diversity
There is production of more than one product which is beneficial to the farmers.

COMPONENTS OF AN AGROFORESTRY SYSTEM

Land
Agroforestry is not a system of pots on a balcony or in a greenhouse. It is a system by which land
is managed for the benefit of the landowner, environment and long-term welfare of society.
While appropriate for all landholdings, this is especially important in the case of hillside farming
where agriculture may lead to rapid loss of soil.

Trees
In agroforestry, particular attention is placed on multiple purpose trees or perennial shrubs. The
most important of these trees are the legumes because of their ability to fix nitrogen and thus
make it available to other plants. The roles of trees on the small farm may include the following:
 Sources of fruits, nuts, edible leaves, and other food
 Sources of construction material, posts, branches, rids and thatching
 Sources of non-edible materials including sap, insecticides, and medicinal compounds
 Sources of fuel
 Beautification
 Shade
 Soil conservation, especially on hillsides
 Improvement of soil fertility

Non-trees
Any crop plant can be used in agroforestry systems. The choice of crop plants in designing such
systems should be based on those crops already produced in a particular region either for
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marketing, feeding animals, or for home consumption, or that have great promise for production
in the region. In keeping with the philosophy of agroforestry, however, other values to be
considered in crop selection include proper nutrition, self-sufficiency and soil protection. Any
farm animal can be used in agroforestry systems. The choice of animal will be based on the value
the farmer places on animal-derived benefits including income, food, labor, non-food products,
use of crop residues, and manure.

Component interaction
Interaction between agroforestry components can be ecological, economical or social. The
interactions basically refer to the effects of woody perennials on other components. These
interactions are often described by the net results which may be;
 Zero/neutral-having no net effect
 Positive- where the components benefit each other
 Complimentary or negative- where the presence of one component interferes with the
wellbeing of another (competitive)

Management in agroforestry is aimed at minimizing competition and maximizing the positive

interaction. Agroforestry components interact with each other through a response effect
relationship. Plants to plant interactions are often mediated by the environment. The plant and
the environment modify each other and the environment then causes an effect on the plant
growth. For example a tree can suppress crop growth by drying the soil or reducing the amount
of sunlight reaching the crop. Thus the tree modifies the environment (soil and light) and these in
turn cause an effect on the crop. Animal plant interactions are more direct through grazing,
browsing, trampling, pollination, seed dispersal and pests and disease transfer.

Competition
Competition occurs when one component reduces the fitness of the other by reducing the
availability of growth resources or by interfering with its environment. E.g.
 Reduction in light available to agricultural crops through shading by tall trees, and drying
of soil around tree stems.
 Competition for growth resources below ground is fundamental and is often the major
cause of low production in agroforestry. This is true with shallow widely spreading roots
such as Albizia spp. and Maesopsis eminii.
 Competition through interference may involve the release of chemicals from leaf litter
that suppresses growth of other components. This is called allelopathy. Pine needles and
eucalyptus litter are thought to have allelopathic characteristics.
 An indirect form of competition is the creation of an environment for pests or pathogens
for the associated component. Trees can be alternative hosts to pests and disease
pathogens of plants. Birds, insects (e.g. tsetse flies and mosquitos) or primates, which are
destructive to crops and livestock, can build nests in trees.
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Complementary
Complementary interactions involve avoidance of competition or enhancement of the fitness of
one component by the other.
 Avoidance of competition can be due to the extraction of growth resources from different
zones. Trees can exploit deep water and leached nutrients while superficial roots of crops
can exploit the shallow soil horizons.
 Nitrogen fixation through association with rhizobia or frankia and enhancement of soil
phosphorous transfer through association with mycorrhizal fungi are some of the
complementary effects of trees on association with crops.

 Animals feeding in shaded environment gain weight faster per unit of food and feed for
long hours. Trees provide support for climbing crops such as passion fruits and vanilla.

 Ficus natalensis has positive effects on banana and coffee systems through shading and
soil fertility enhancement.

 Some slow growing trees such as Fiadherbia albida, Parkia biglobosa and
Vitelleria paradoxa are known to enhance soil fertility over time. However,
some exotic nitrogen-fixing species such as Leucaena leucocephala,
Calliandra calothyrsus and Gliricidia sepium are known to enhance soil
fertility over a short time scale. These are often grown as improved fallows
or in a cut and carry system.

Characteristics of Ideal agroforestry species

Some trees or shrubs may not be used in agroforestry system. A good agroforestry tree
spp. should have the following characteristics;
i. It should be deep rooted with a narrow zone (limited lateral spread) to reduce
competition with shallow rooted crops and to recycle nutrients. This enables
it to absorb nutrients from the deeper layers of the soil where crop roots
cannot reach.
ii. The trees should be multipurpose i.e. produce various products like timber,
fuel, and poles for construction
iii. It should be fast growing with high biomass production
iv. It should be easy to establish and get rid of
v. It should not be very competitive with crops because this will lower the yield
of other crops by competing with crops for nutrients, light and moisture
vi. The tree spp. should be nutritive and palatable to as leaf fodder for feeding
livestock mainly during the dry season
vii. It should be nitrogen fixing. It is advisable to plant at least tree species which

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 have the ability to fix nitrogen into the soil
viii. It should be able to produce economic products and by-products that can be
useful or sold by the farmer to earn some income e.g. fruits and poles
ix. It should have a light canopy i.e. the branches; leaves should not be very
thick in order to allow light penetration
x. It should be able to re-grow after cutting so as to ensure continues collection
of fodder for the animals and continues harvesting of the tree products
xi. The agro-forestry species should be tolerant to drought so that during the dry
season fodder is available for the animals
xii. Companion growing the tree species should support harmony of various
plants in the system

Generally, such characteristics together with other good management provide positive
interaction between trees and shrubs and associated crops and livestock. The specific
desired traits will depend on the farmer’s wants and needs.

BENEFITS OF AGROFORESTRY
The benefits of agroforestry can be categorized into environmental, economic and social
benefits.
A) Environmental benefits
i) Reduction of pressure on natural forests
ii More efficient recycling of nutrients by deep rooted trees on the site
iii) Better protection of ecological systems
iv) Reduction of surface run-off, nutrient leaching and soil erosion through impeding effect of
tree roots and stems on these processes
v) Improvement of microclimate, such as lowering of soil surface temperature and reduction of
evaporation of soil moisture through a combination of mulching and shading
vi) Increment in soil nutrients through addition and decomposition of litter fall
vii) Improvement of soil structure through the constant addition of organic matter from
decomposed litter
Viii) Provision of fodder for the animals especially if pastures are integrated into the system

B) Economic benefits
i) Increment in an outputs of food, fuel wood , fodder, fertilizer and timber
ii) Reduction in incidence of total crop failure, which is common to single cropping or
monoculture systems
iii) Increase in levels of farm income due to improved and sustained productivity

C) Social benefits

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i) Improvement in rural living standards from sustained employment and higher income
ii) Improvement in nutrition and health due to increased quality and diversity of food outputs
(food security)
iii) Stabilization and improvement of communities through elimination of the need to shift sites
of farm activities

Why farmers resist tree growing

i. Trees out compete the rest of the crops for nutrients, water and shade therefore end up
causing considerable loss to the farmer
ii. Trees are not edible and most of them do not produce food for the farmer
iii. Trees take long to mature; this discourages many people who think that they have to wait
for a long time before starting to get returns/benefits from agroforestry
iv. Some farmer are not sensitized on the usefulness of the trees and end up planting just to
please the extension
v. Some farmers are not sure of what will happen to their land when they plant trees, some
think the trees will spoil their land
vi. Most of the farmers have small land holdings; so there is competition between the trees
and the crops. They prefer to grow annual crops to feed their families.
vii. Market; there is limited market for agroforestry products in some places most especially
in rural areas

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TOPIC TWO: AGROFORESTRY SYSTEMS

An agroforestry system is characterised by a unique environment and socio-economic conditions,

specific component species and their arrangement as well as management. Agroforestry systems
can be classified in different ways using structural and functional considerations as:
agrisilvicultural, silvopastoral and agrisilvopastoral systems which can be further sub-divided
depending on specific arrangements and/or functions.

Agrisilvicultural
This system combines the growing of crops with trees on the same piece of land. Some
commonly used agrisilviculture systems include alley cropping, scattered trees on crop land,
improved fallows and hedgerow cropping. Agrisilviculture seeks to create harmony between
crop farming and tree farming. The system can be subdivided into simultaneous and sequential
systems.

(a) Simultaneous agrisilviculture. Trees and crops are grown on the same piece of land at
the same time. The major concern in this system is the ecological interaction between the
components. The examples of such a system are the banana-coffee system in central
region with Ficus trees, Borassusae thiopum-millet system and Vitelleria paradoxa-millet
and or groundnut system in the north. Boundary markings, alley cropping, barrier hedges,
fodder banks, live fences and home gardening are other examples. Here, management
should aim at limiting interspecific competition.

(b) Sequential agrisilviculture. Here, trees and crops components occupy the same piece of
land at different times and the interaction between them is indirect. Trees are cleared
from an area, crops are grown for some years and when the soil becomes less productive,
the land is left to naturally regenerate a bush fallow and the cycle continues. This is
shifting cultivation. In other instances, growth of the crop and tree components occur at
different times even when both components may have been planted at the same time. In
the improved fallow system, planting of fast growing nitrogen fixing trees and shrubs
(such as calliandra calothyrsus and Sesbania sesban) enhances land productivity (soil
fertility in general).

Silvopastoral
This system involves growing trees and raising of domesticated animals and/ or pastures on the
same piece of land in a mutually beneficial way. The main crop is trees, but forage crops are
grown under the trees for grazing livestock. The trees provide timber, fruit, or nuts as well as
shade and shelter for livestock and their forages, reducing stress on the animals from the hot sun,
cold winds, or a downpour. Examples include fodder banks, live fences and live fence posts.

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These systems are intensively managed for both forest products and forage. In the grazing
system it supplements animal feeds or to provide high quality fodder in times of drought when
grass is scarce. Well managed silvopastures employ agronomic principals, typically including
introduced or native pasture grasses, fertilization and nitrogen-fixing legumes, and rotational
grazing systems that employ short grazing periods which maximize vegetative plant growth and
harvest.

Advantages of a properly managed silvopasture operation are enhanced soil protection and
increased long-term income due to the simultaneous production of trees and grazing animals.

Benefits of Silvopastoral
i. Cooler environment for livestock
ii. Shorter timber rotations due to forage fertilization and competition control
iii. High value timber products resulting from pruning and management of tree density
iv. Shaded, cool season forage plants can be more nutritious for livestock
v. Diversification of income spreads out market risk and increases income opportunities
vi. Greater plant nutrient uptake efficiencies - the deep tree roots coupled with pasture plant
roots acquire nutrients from a greater range of soil depths

Agrisilvopastoral
This system involves a three-way mixture based on a combination of crops, trees and animals. It
involves growing crops, planting trees and raising animals/agricultural commodities to mix along
with trees and animals. Such a system requires skillful management, and can be sustainable even
in harsh environments and fragile soils.

Under these two specialized systems include:

Entomoforestry. This refers to the rearing of useful insects in association with trees. The two
common types of entomoforestry include apiculture (bee keeping) and sericulture (silkworm
rearing). When hives are set in trees and bees forage from tree flowers for nectar, then apiculture
becomes agroforestry. This requires little capital investment, but with high potential for income
generation through sale of honey and wax. Sericulture is practiced mainly in Asia (China and
India) where the Morus alba tree provides food for worms reared for production of silk. In
Uganda it has been tried on small scale in Bushenyi, Kabarole and Wakiso districts. It is limited
by lack of skill and poor access to markets.

Aquaforestry. A combination of trees and aquaculture (trees with fish) e.g. trees are planted on
the boundary and around fish ponds. Leaf litter enriches the water with nutrients for fish
production and the tree leaves are also used as feed for the fish. The main role of this system is
fish production and bund stabilization around fish ponds. Swamps in Uganda are characterized

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by shrubs, trees and palms that provide food, shelter and cover for fish and other animals against
high temperature and excessive surface evaporation.

Advantages of agrosilvopastoral systems

i. Diversification of production activities within the farm reduces risk of economic
disasters.
ii. Small farmers, with land limitations, may use the forest to produce food from animal
origin (milk, meat) without sacrificing areas dedicated to crops.
iii. Farmers may also obtain economic benefits from fuel wood, timber, posts, and forage,
which are used eventually in the farm for cattle management.
iv. In the case of associations of cattle with crops, the principal advantage is that between 60
and 70% of plant biomass can be used as feed for cattle without causing competition
problems with crops for human consumption.
v. In the particular case of cattle associated with nitrogen-fixing trees, these species will
contribute to soil fertility, in addition to being a protein supplement when their edible
parts are utilized as forage.

Disadvantages of silvopastoral
i. Compaction effects on the soil are harmful but could be compensated for by the effect
tree roots have on soil porosity, infiltration capacity and soil aeration.
ii. Velocity and size of water drops from tree crowns to plants or crops under them can
cause damage to flowers and fruits.
iii. Cultural practices, such as mechanized harvest of crops are interfered with by the trees.
Planning with sufficient space is necessary.

Classification of agroforestry based on arrangement of components

The classification based on arrangement of components gives first priority to the plants. Even in
agroforestry systems involving animals, they are managed according to a definite plan.

1) Spatial Arrangement
Spatial arrangements of plants in an agroforestry mixture may result in dense mixed stands ( as
in home gardens) or in space mixed stands (as in most systems of trees in pastures). The species
(or species mixtures) may be laid out in zones or strips of varying widths. A common example of
the zonal pattern is hedgerow intercropping (alley cropping).

2) Temporal Arrangement
Temporal arrangements of plants in agroforestry may also take various forms. An extreme
example is the conventional shifting cultivation cycles involving 2-4 years of cropping and more
than 15 years of fallow cycle, when a selected woody species or mixtures of species may be
planted. Similarly, some silvopastoral systems may involve grass leys in rotation, with some
species of grass remaining on the land for several years. These temporal arrangements of

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components in agroforestry are termed coincident, concomitant, overlapping (relay cropping),
separate and interpolated.

Make short notes about multi-strata plant communities

AGROFORESTRY PRACTICES
An agroforestry practice can refer to a management practice in an agroforestry system or the
arrangements of agroforestry components in space and time. It also refers to a land management
where there is a distinct arrangement of crops, tress and livestock in space and/ or time. When an
agroforestry technology has been widely adopted and implemented, it becomes practice. Within
each agroforestry practice, there are a number of options available to landowners depending on
their own goals (e.g. whether to maximize the production of inter-planted crops, animal forage,
or trees).

a) Agroforestry practices for soil conservation and fertility enhancement

i. Contour hedges
The main aim of contour hedges is soil erosion control. They consist of trees/shrubs planted
along contour lines, with or without grass strips. Species suitable for barrier hedges include
Calliandra, Inga edulis, Fleminga, Leucaena diversifolia and Peltophorum pterocarpum, Senna
spp., Grilicidia sepium, Grevillea, F. natalensis and Sesbania sesban. At each contour, a single
or multiple rows of shrubs can be planted depending on the severity of the soil erosion problem.
The practice is common in highland areas such as in Mbale and Kabale. The trees/shrubs planted
on the slopes can significantly reduce the speed of water and soil movement. The byproducts
from pruning can be used as livestock feed, stakes for climbing plants (beans in Kigezi,
tomatoes), green manure and firewood.

Contour hedge establishment should be preceded by location of contour lines using the A-frame
and spirit or line level. Spacing between individual plants in the hedge varies from 20 to 40 cm.
The hedge can either have one or two lines of plants. The spacing between contour hedges varies
from 5 to 20 m depending on the slope of the land. On slopping lands trees or shrubs require

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reinforcement with grasses e.g. Penniseteum purperium, Panicum maximum, Chloris gayana,
Cynodon dactylon and legumes like Desmodium spp. on the upper slopes or both sides of the
hedge to reduce runoff. Grasses and legumes should be planted after the trees have established to
reduce competition. The contour hedges should be pruned at knee height (30 cm or 1ft) regularly
to minimize competition with adjacent crops, at least twice in a season. However, the frequency
of cutting depends on the growth of the shrub species.

ii. Improved fallows

Improved fallows are an improvement of shifting cultivation by causing biomass production and
nutrient accumulation in the soil in a shorter period. It involves use of fast growing, nitrogen
fixing trees or shrubs to restore the fertility of exhausted soil. Leguminous species such as
sesbania sesban, Lueceana leucocephala, L. diversifolia, Calliandra calothyrsus, crotalaria
cunninghamiana, Tephrosia vogellii are grown for one season or one year, cut and ploughed into
the soil. Crops can then be grown until soil is exhausted. Other useful products from improved
fallows include fuel wood, construction material for traditional structures and stakes, weed
control, suppression of the build up of insect pests and pathogens, soil erosion control and
animals can be grazed directly on the fallow land.

iii. Rotational woodlots

Rotational woodlots are used to revitalize exhausted soils while providing woody products such
as fuel wood, stakes and poles. The trees are usually grown for 1-3 years, after which they are
cut and replaced with a food crop. The common species include Lueceana leucocephala, Alnus
acuminate, Markhamia lutea, Calliandra calothyrsus and Albizia spp. The trees are established
at a close spacing such as 2m x 2m for quick production of biomass and suppression of weeds.
The trees are clear cut after 2-3 years there after a crop can be planted at the site.

B. Agroforestry practices for wood and energy production

i. Boundary planting
Boundary planting is an agroforestry practice where trees are used to demarcate boundaries. The
tree species must be compatible with adjacent crops and acceptable to the neighboring farmer

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since the boundary is a shared resource. Common boundary species in Uganda include Dracaena
fragrans, Markhamia lutea, Euphorbia triculii and Alnus acuminate.

Line planting is a similar practice but the trees do not necessarily follow boundaries. The trees
can provide multiple products such as building poles, timber, firewood and fruits. They can also
act as windbreaks. Line planting can be used to demarcate paddoks and provide shade in
silvopastoral farming.

Tree species commonly used in this practice Grevillea robusta, Markhamia lutea, Casuarinae
quisetifolia, Maesopsis eminii, Melia volkensii, Senna spectabilis, Maesopsis eminii, Tithonia
diversifolia and sesbania sesban. Trees can be planted initially at 5m spacing along plot
boundaries, contours or roadsides. The trees can be thinned to a spacing of 10m or more to
improve stem form. The remaining trees can be pruned regularly to avoid shading of adjacent
crops. The cuttings can be used for fire wood or stakes. However boundary tree planting can
bring conflict between neighbors and may harbor pests and diseases.

ii. Trees scattered in cropland

It is common for trees to be deliberately planted or retained in cropland at irregular spacing for
poles, firewood, fruits, timber, fodder and medicine etc. The tree species commonly used in this
practice include Albizia spp., Grevillea robusta, Ficus spp., Markhamia lutea, Pesea amaricana,
Magnifera indica, Vitelleria paradoxa, Tamarindaus indica, Milicia excelsa etc. The trees
species vary with location and farming system.

Trees should be initially planted 10 X 10 m to reduce competition and enable land clearing,
planting and weeding of crops. At this spacing, 100 to 200 trees can be planted in 1 ha of land.
Naturally growing trees can be reduced to the recommended spacing. Young trees should be
weeded and protected from animals. Scattered trees can provide shade for crops, improve soil
fertility and microclimate and improve the natural beauty of the farm land especially in
silvopastoral systems. However, the trees may take long to mature, harbour pests (especially
birds) and diseases and compete with associated crops. Trees can destroy crops and property
during harvesting.

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 iii. Woodlots
Woodlots may constitute a single or mixture or tree species established for poles, fuel wood, and
sometimes timber. The common species used are Eucalyptus spp., Pine spp., Cupressus
lusitanica, Maesopsis eminii, Terminalia ivorensis and Grevillea robusta. They are often
established on marginal (e.g. steep slopes) or idle land. A woodlot keeps the soil surface
covered.

Woodlots are normally established from seedlings and when planted near homesteads tree rows
should be perpendicular to the direction of wind to avoid destruction to buildings. The
establishment requires land preparation, purchase and planting of seedlings, weeding pruning
and thinning as the most important management activities. The spacing varies between tree
species e.g. Eucalyptus 2 x 2 m, Pine 2.7 x 2.7 m and Grevillea 3 x 3 m.

The woodlots are often established for income generation. The challenge is that they require a
large land area and high establishment costs. Stamp removal is costly and marketing of products
(e.g poles) is difficult because of poor roads in remote areas. The greatest risk to woodlot
management is fire. Woodlots may also provide cover to criminals and vermin.

C. Agroforestry practices for livestock production

i. Fodder banks
A fodder bank is an agroforestry practice in which trees/shrubs are planted to provide livestock
feed especially in times of scarcity. It can be defined as an enclosed area of forage legumes
reserved as supplementary feed during dry seasons or acute shortages of pastures. Fodder banks
are common in areas where grazing land is scarce due to high population density or in peri-urban
areas. Fodder banks usually contain tree/shrubs legumes established for the protein or mineral
deficiency of grasses. They help to increase supply of fodder and bridge the dry season feed-
gap. The common trees used include Leuceana species, Sesbania spp., Gliricidia sepium and
Calliandra callothrysus, Ficus natalensis, Acacia angustissina, Acacia tortilis, Dodonaea
angustifolia and Vernonia amygadalina.

ii. Trees in rangelands and pastures

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Trees in range land or pastures are either scattered or arranged in a systematic pattern to provide
shade and fodder for livestock. Grasses tend to grow better under trees. Some of the common
tree species include: Acacia spp., Ficus spp., Anus acuminate, Abizia spp., Combretum spp., and
Prosopis juliflora. Trees can either be planted or retained through natural regeneration for fodder
and other tree products.Trees maintain the stability and fertility of grazing lands and provide
fodder reserves in dry seasons. On the other hand, trees can become weeds if not well managed
and can also harbor pests and diseases and attract birds.
iii. Home gardens
Home gardens consist of a mixture of vegetables, fruits, medicinal and fodder plants in small
intensively cultivated plots around the homesteads. Home gardens can remain productive for
over long time with little or no agrochemical inputs and are normally managed at a subsistence
level using household labour.

Trees in home gardens may be planted or retained from natural regeneration. Over time, home
gardens may be enriched with a variety of species beneath the open canopy. Due to the intimate
complexity of species, home gardens are not prone to complete crop failure or disease and insect
attack. Desirable tree species include Cordia abyssinica, Albizia Spp., Grevillia robusta, Ficus
natalensis, Merkhamia spp., Maesopsis eminii and Milicia excelsa.

D. Agroforestry practices for fruit production

i. Buffer zone agroforestry
Buffer zone agroforestry is practiced around protected natural resources managed for
conservation purposes. It contributes to the conservation of biodiversity by the purposeful
integration of trees on farmlands so as to reduce pressure on protected natural ecosystems.
Usually buffer zone agroforestry enables farmers to achieve food and wood security and generate
income. It is a common practice around Mabira, Bwindi and other forested areas with high
pressure for tree products from adjacent population.

ii. Apiculture with trees (api-silviculture)

Apiculture is the rearing of bees. Where bees are reared in combination with trees, is referred to
as api-silviculture. Carefully chosen woody species for their nectar-producing flowers and pollen

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valued by bees can boost honey and wax production, particularly if flowering is staggered. This
is probably the practice with the highest ration of value products harvested to plant biomass
consumed. Trees that produce good nectar are established in woodlots, weeded and pruned for
flower production. Bee hives are introduced when trees start to flower.

iii. Aquaculture
Woody species that are palatable to fish are planted near fish ponds to boost fish production. The
tree leaves are frequently cut and fed to the fish in the pond. Some fish ponds can be established
in home-gardens and the woodlots where the leaf litter is readily used as fish-feed. The trees
provide food and a favorable microclimate.

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TOPIC THREE: TREE NURSERY ESTABLISHMENT AND MANAGEMENT

Introduction
There are three methods of raising planting materials of trees. These are from wildlings (a plant
especially a seedling, that is growing wild or has escaped from cultivation), seed and vegetative
parts of plants. To raise good quality tree planting materials, it is important to identify good seed
sources and individual trees from which seeds and other propagation materials can be collected.
These will look at how to collect, handle and process seed and other propagation materials; and
how to raise seedlings from seed.

(a) SEED
A seed can simply be defined as a tree in its resting stage awaiting favorable conditions to start a
new life. On the other hand, seed handling refers to all the activities involved in collecting,
processing and storage of seed before the next planting.

Seed collection and handling

For sustainability of tree planting activities, farmers and all those involved in tree planting
activity should have a good knowledge in seed handling.

Sources of seed
Seeds can be either purchased from central seed supplies or collected locally. Collecting seed
locally has the following advantages.
 Adaptation to the local conditions
 Use of fresh and viable seed in planting
 Can be able to select the desired characteristics from the mother plant
 No expenditure involved in purchases

Seeds should be collected from trees growing over a large area and in similar ecological zone.
The place where the seed in collected should be as similar as possible to the place where the
seedlings will be planted.

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To obtain good quality seed, the following factors should be carefully considered:
 Collect from vigorous, healthy mature trees of good form.
 Do not collect seed from isolated trees (a good mother plant should not be isolated).
 Collect seed from a minimum of ten trees spaced at least 100 m apart.
 The mother plant/ tree should have seeded at least 2 times (normally the 1st seeding
produces poor seeds).
 Should have a conical growth with the first branching high up.

Generally, the type of product desired from a tree determines the characteristics to be looked for
in the mother tree.

Table 1: Typical characteristics for mother trees for specific types of tree products

Desired types of tree/products/services Characteristics of mother tree (source)

Timber Straight stem
Few branches
Hard wood
Fuel wood Many branches
Fast growing
Producing little smoke/nontoxic smoke
Wood that burns for a long time
Able to re-grow after cutting (coppice)
Shade Many leafy branches
Little litter fall/ever green
Continuous flowering
Strong stem
Soil and water conservation Able to grow together with food crops
Able to re-grow after cutting
Nitrogen fixing
Many leafy branches
Ornamental/beauty Good and nice looking
Continuous flowering
Little litter fall
Fodder Many leafy branches
Able to grow together with crops
Nitrogen fixing
Nutritious and palatable fodder
Fruits Branching at lower level of the stem
Resistance to disease and pests
Fast maturing
Good quality fruits

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Seed collection methods
This refers to the real action of picking and gathering of seeds for planting. There commonly
three methodscollecting seed. These include:

(a) Collection from fallen fruits or seeds (Natural/ induced fall)

In many species, the fruits/ seeds fall naturally when ripe and can be easily collected from the
ground. This method requires careful selection of fruits or seeds. Fruits or seeds that have been
attacked by diseases or pests should not be collected. It is advisable to know the period of heavy
fruiting or seeding. When this period is known, a canvas material or mat is placed under the trees
to prevent seeds from gaining direct contact with the soil. Examples here include Maesopsis
eminii, Szygium cuminii, Terminalia mentalis etc.

Advantages
 Doesn’t require skilled labour (natural fall)
 Easy to collect a large amount of seed (induced fall)
 No damage to the mother tree (natural fall)
 High possibility of getting mature seed
 Seeds can be collected from desired mother trees by induced fall

Disadvantages
 Seeds from inferior mother trees may be collected (natural fall from tree stand)
 Seeds can be attacked and damaged by insects and fungi.

(b) Collection from standing trees

This method requires climbing into the crown to pick fruits or seeds. It is advisable to use this
method if one is sure that the tree has strong branches that can provide support during climbing.
Ladders, ropes and hooked poles can be used to collect the seed from the crown. The person
harvesting the fruits/seeds should be experienced so that you do not collect premature seeds. The
examples here include Greville arobusta, Albizzia coriaria, Psidium guajava etc.
Adavantages
 Seeds are collected from trees of desired characteristics.
 High possibility of collecting mature seeds.

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  There is minimal damage to seed/fruits by insects or fungi.

Disadvantages
 Mother trees may be damaged.
 Requires skilled labour.
 Seed wastage by cutting off branches.
 Method is risky (climbing).

Collection from crowns of trees

In this method the seeds or seed bearing fruits are accessible from the ground. When harvesting
trees for their products, it is advisable to harvest them when they are bearing mature seeds. In
this way the seeds can be used for raising seedlings for planting.

SEED PROCESSING AND POST-HARVEST HANDLING OF SEEDS

Seed handling refers to activities like cleaning, sorting and storing seeds for future planting
needs.

Pre-cleaning
All unwanted material (bark, twigs, or leaf pieces) should be removed from the fruits and seeds
right after collection.

Seed extraction
This is the separation of seeds from the fruits. Seeds are always embedded in capsules pods or
cones. The method used depends on the nature of the fruit (cones, capsules or pods). Capsules
e.g. Grevillea, Cones e.g. Pines, Pods e.g. Tephrosia. Some fruits need de-pulping; others need
drying until seeds become detached from the fruit. Others need the use of a knife. Some fruits
such as nuts do not require extraction but are stored or sown as fruits.
The extracted seed should be cleaned by separating healthy seeds from empty and non-viable
seeds, de-wining seeds and grading seeds by size and appearance. Grading seed is recommended
but may not be necessary if only a small amount is processed for direct use.

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Seeds from pulpy fruits, for example Kiryowa (Fatrophacurcus), Kei apple (Dovyalis caffra),
Musizi (Maesopsis eminni) and paw paws (Carica papaya) should be dried under shade until the
surface has no moisture. Seeds contained in hard pods such as those of Nongo (Albiziazygia),
Lusina (Leucaena leucocephala), Calliandra calothyrsus, Kasaana (Acacia species) and
Sesbania sesban should be dried in the sun.

Why carry out seed extraction?

 To facilitate storage (reduce the bulk).
 Remove the fleshy part (pulp) that can attract insects and fungi.
 To improve on germination, by removing the hard coat, flesh which contains some
germination inhibitors (chemicals), removing the flesh which also attracts insects and
fungi.
 To improve on quality.

Methods of seed extraction

a) Maceration/Depulping.
b) Drying and shaking.
c) Biological method.
d) Drying.

i. Depulping/maceration
Extraction of the seed must be done as soon as they are collected because seeds that stay in their
pulp run the risk of losing their viability due to overheating and fermentation due to chemicals in
the pulp that initiate dormancy mechanisms thus inhibiting subsequent germination of the seed.
Extraction of this type involves soaking in cold water for 24 hrs. The soft fruits are then
squeezed by rubbing in the hand or against a wire mesh. E.g. Polysciasfulva, Maesopsis eminii,
zadirachta indica etc. Another method of extracting pulpy fruits is by pounding the fruits with a
pestle in a mortar after soaking e.g. Melia azaderach.

ii. Drying
Most seeds in non-pulpy fruits can easily be extracted by drying them under the sun or artificial
heat; however not exceeding 450C. The fruit will open up releasing the seeds, thus facilitating the

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separation from the fruit. Never use polythenes while drying the seeds because this can raise
temperatures to injurious levels.

iii. Drying and shaking (Threshing)

Some types of fruits mainly pods open when dried but the openings are often not wide enough to
release the seed. These are often enforced by shaking them against some surface to help release
the seed.

iv. Biological
Seeds are spread on the ground and covered with a thin layer of dump soil in an area with
abundant termites, which can eat up the pods leaving the clean seeds. This method is however
slow probably due to other feeding materials at the termites disposal.

v. Seed sorting /grading

After seed extraction, the seed should be sort and graded according to size, vigour, or general
appearance. All the marginalized seeds are removed leaving only the healthy vigorous seed to
use for planting. The extracted seed should be cleaned by separating healthy seeds from empty
and non-viable seeds.

SEED STORAGE
This is preservation of viable seeds from the time of collection until when they are required for
sowing. The period for which seed can remain viable without losing germination capacity is
greatly affected by quality at the time of collection, treatment between collection and storage and
conditions in which seed is stored.

Mature seeds free of pests and diseases and without physical damage can be stored for a time
under room conditions. But it is advisable to saw seeds soon after harvesting so that most of the
seeds can produce seedlings. Seeds of most agroforestry trees should be dried before storing.

Why store seed?

i. To wait for sowing season.In most cases harvesting does not coincide with the planting
time, so seed must be kept in storage for some period.

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 ii. Availability. It is always useful to have seeds in store to satisfy demand from farmers
and other customers.
iii. Provision for poor seeding season and quality. Trees do not produce the same amount
of seed every season. Heavy seeding yields seed of better quality and of better ability to
store. Therefore, seeds from good fruiting seasons are stored for use in poor or no seeding
season.

Preparing seed for germination

Seeds of most tree species, particularly those of leguminous agroforestry shrubs like calliandra
germinate easily. Seeds of some types of trees need treatment. There are many methods of
treating of seeds to improve germination. These include cutting, soaking in water, drilling or
cracking the coat of seed before sowing. Rubbing with sandpaper may reduce the seed coat.
Seeds can be soaked for one day in warm water at room temperature. (Find the attached copy for
the treatment methods of different agroforestry trees).

(b) VEGETATIVE “SEED” MATERIAL

Vegetative propagation is the growing of trees from cuttings or other non-seed materials such as
roots, bulbs and suckers. The cuttings can be obtained from stems, leaves and branches.

Advantages
1. Quick maturity
2. Diseases and pests resistance
3. Adaptability to different soil and environment conditions
4. Better yields
5. Improved quality
6. Plants which can not be propagated by other methods

Disadvantages
1. Requires a lot of skills

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 2. Time consuming
3. Labour intensive

A. Stem/root cuttings
These may be stems or root cuttings. A stem cutting is a section of a stem that will send out roots
when placed in the soil. Tree species propagated by stem cuttings include: Ficus natalensis and
Grilicidia sepium, Morus spp., Euphobia triculli, Manihot glaziovii and Erythrina spp. Guava
ssp can produce shoots from root cuttings. The cuttings should be:-
 Mature.
 Have at least 2 internodes.
 Be about 10-15 cm long.

The cuttings should be inserted in the growth (rooting medium) in the upright or slanting
direction with at least 2/3 of it submerged in the rooting medium. This can be done directly in the
field or in pots in a nursery.

The quality of cuttings, treatment of stock material and environmental conditions during rooting
of cuttings can affect the process of rooting. The season of the year will also affect the process of
rooting of cuttings. Application of growth promoters such as rooting powder will increase
chances of growth.Cuttings should be raised in well aerated, warm areas free from pests and
diseases. The soil should be of good quality and well drained.

B. Layering
Layering is a means of plant propagation in which a portion of an aerial stem grows roots while
still attached to the parent plant and then detaches as an independent plant. This can also be
defined as is a method of asexual propagation in which a stem is made to produce roots while
still attached to the parent plant.
Methods of layering
 Compound layering
 Mound layering
 Air layering
 Simple layering

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  Tip layering
 Ground layering

(i) Simple layering procedures

 Bend a low growing flexible the stem to the ground.
 Cover part of it with soil leaving the remaining 6 to 12 inches above the soil.
 Bend the tip into a vertical position and stake in place
 The sharp bend will often induce rooting, but wounding the lower side of the bent branch
may also help.
 Examples of plants propagated by simple layering include climbing roses.

Simple layering

(ii) Compound (serpentine) layering is similar to simple layering, but several layers can result
from a single stem. It involves looping the stems of climbers in and out of the soil to encourage
roots to form at several points along the same stem. The technique for each buried section is
very similar to simple layering. Thin-stemmed climbers need not be wound.

Procedures
Bend the stem to the rooting medium as for simple layering, but alternately cover and expose
sections of the stem. Each section should have at least one bud exposed and one bud covered
with soil.

Compound layering

Wound the lower side of each stem section to be covered. This method works well for plants
producing vine-like growth such as ornamental plants and grapes.

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(iii) Mound layering procedures
 Cut the plant back to 1 inch above the soil surface in the dormant season. Dormant buds
will produce new shoots in the spring.
 Mound soil over the new shoots as they grow. Roots will develop at the bases of the
young shoots.
 Remove the layers in the dormant season. Works well on heavy-stemmed, closely
branched shrubs and rootstocks of tree fruits.

Mound layering

(iv) Air layering procedures

 Make an upward 1-1.5 inches cut about one-third through the stem. The cut is held open
with a toothpick or wooden match stick.
 Surround the wound with moist rooting medium (about a handful) that has been soaked in
water and squeezed to remove excess moisture.
 Wrap the plant with plastic or aluminium foil and hold in place with twist ties or
masking tape.
 After the rooting medium is filled with roots, sever the stem below the medium and pot
the layer.
 The new plant will usually require some close attention until the root system becomes
more developed.
 Provide shade and adequate moisture until the plant is well established. Here are the
steps used in air layering.

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 Pot up the new plant.

When a strong root system has formed, cut off the stem below the roots. This can take six to
eight weeks.

(v) Tip layering. This one is quite similar to simple layering.

Procedures
 Dig a hole 3 to 4 inches deep.
 Insert the tip of a current season’s shoot and cover it with soil.
 The tip grows downward first, then bends sharply and grows upward.
 Roots form at the bend.
 The re-curved tip becomes a new plant
 Remove the tip layer and plant it in the beginning of the rain season.
 Examples of plants propagated by tip layering include purple and black raspberries, and
trailing blackberries.

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 Tip layering
(vi) Ground layering
Plants with low growing trailing stems can be ground layered. This type of plant naturally layers
so a plant propagator can take advantage of this growing habit. You can ground layer blackberry,
ground cover rosemary, and vines like sweet potatoes

Procedures in ground layering

 Choose a healthy, young stem growing close to the ground. It must be flexible so it can
be bent down to lie along the soil surface.
 Remove the leaves from the area to be layered.
 Expose the cambium tissue to the soil.
 On the underside of the stem, make a small cut one third of the way through the stem.

This exposes the cambium tissue where the roots will form.
 Dust the cut with rooting hormone powder.
 Slip a matchstick into the cut to keep it open and expose the cambium tissue to the soil.

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  Peg the stem to the ground, cover the cut in soil and keep it damp. This allows roots to
form from the cambium tissue.
 Some leaves may need to be removed from the end of the wounded stem to prevent
wilting.
 Attach the upright stem of the layered stem to a stake. This will help it grow upright.

 Cut the new plant from its parent when a root system has grown.
 Plant the new plant in fertile soil and keep it moist.

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The reasons for caring out layering in agro forestry
 The parent plant supplies the new individual with water and food, particularly
carbohydrates and proteins, and hormones, particularly the auxins, until it makes its own
food and hormone.
 Comparatively bigger plant could be obtained through layering.
 It is possible to avoid mutagenic effects in certain species that happened if propagated by
cutting.
 It is possible to generate few individuals of important species with minimum propagation
facilities.
 It is possible to vegetatively propagate plants that are difficult to root
 It improves on early maturity of the plant.
 Some species are difficult to propagate by use of seed.

C. Grafting
This is the art and science of connecting two pieces of living tissue together in such a manner
that they will unite and subsequently develop as one plant. The lower part is called the stock and
the upper part is the scion. The root stock is from the local specie (e.g. local mango) and the
scion from the improved variety.
Reasons for grafting
1. Rapid propagation of clones, which cannot be readily, propagated by other easier means,
e.g. hybrid passion fruit.
2. Changing the tops or cultivars like in some cases citrus and mangoes.
3. Grow more than one fruit or flower on one plant (top working) like in mangoes.
4. Helps to obtain special plants for the farm such as multi coloured tree roses.
5. It is used to reduce time to maturity as is the case in avocado and mangoes.
6. Used for studying or testing for resistance or plant tolerance to viral diseases e.g. a
variety studied to a susceptible stock and then observing the reaction.
7. Taking the advantage of desirable stocks to improve on good features like disease
resistance, tolerance to drought and water logging, growth vigor.
8. Grafting helps to repair damaged part of the plant (bridge grafting).

Materials and equipment

 Grafting knife/surgical blade.
 Scion
 Rootstock

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  Polythene paper.
 Secateurs

Selecting and Handling Scion Wood

i.
The best quality scion wood usually comes from shoots grown the previous season.
ii. Scions should be severed with sharp, clean shears or knives and placed immediately in
moistened burlap or plastic bags.
iii. Clean the cutting tools during the harvesting of scions and the making of grafts. This may
be done by flaming or immersing them in a sterilizing solution. Isopropyl (rubbing)
alcohol also works well as a sterilant, although it evaporates quite readily. An alternative
sterilizing solution may be prepared by mixing one part household bleach with nine parts
water (by volume).
iv. For best results, harvest only as much scion wood as can be used for grafting during the
same day.
v. Select only healthy scion wood that is free from insect, disease, or winter damage.
vi. Be sure the stock plants are of good quality, healthy, and true to type.
If large quantities of scion wood must be harvested at one time, follow these steps:
 Cut all scions to a uniform length, keep their basal ends together, and tie them in
bundles of known quantity (for example, 50 scions per bundle).
 Label them, recording the cultivar, date of harvest, and location of the stock plant.
 Wrap the base of the bundles in moistened burlap or sphagnum, place them in
polyethylene or waterproof paper bags, and seal the bags.
 Store the bundles for short periods, if necessary, either iced down in insulated
coolers or in a commercial storage unit at 32° to 34°F.
 Never store scions in refrigerated units where fruits or vegetables are currently
kept or have been stored recently. Stored fruits and vegetables release ethylene
gas, which can cause woody plant buds to abort, making the scions useless.
 Keep the scions from freezing during storage.

a) Procedure for whip or tongue grafting

 Select a healthy rootstock of pencil thickness and knee height and the scion of the same
size from a healthy plant of the desired variety.

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  Remove all the leaves from the scion and keep the scions moist in order to prevent
wilting or drying.
 The common method used in mango propagation is the whip or tongue grafting, it is used
in small planting material whose stock and scion diameter are similar.
 Make a slanting cut with a sharp knife at the base of the scion and the top of the root
stock (A and C).
 For the tongue, make a straight draw cut (not split), beginning near the top and cutting
about the full length of the level (B and D).
 Fit the two parts tightly together (E) and secure using a grafting tape .
 Cover the whole scion with the polythene paper by rolling the tape covering the whole
scion from the graft joint.
 After three weeks the scion will start shooting and the polythene covering it can be
removed.

Figure 1: Whip graft

b) Cleft grafting
The cleft graft is used for top working older established apple and pear trees, either on the trunk
of a small tree or on the side branches of a larger tree. It is best adapted to branches 1 to 2 inches
in diameter. The grafts are made within 2 to 3 feet of the trunk or main branches and preferably
not more than 4 to 6 feet from ground, or new top of tree will be too high.

Procedure
 Select a place free from knots and cut off the stock with a saw. Cut the cleft (avoid
splitting if possible) with a grafting chisel, large knife or hatchet. In horizontal branches,
the cleft should be sidewise, that is, not perpendicular, to reduce breakage from birds and
storms.

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  With a sloping cut about 1/4 inch above the upper bud, cut the scions to include three
buds, and to a blunt wedge about 1.5 inches in length with one side slightly thicker than
the other (see A and B)
 Open the cleft slightly with a grafting tool or screw driver. Insert a scion on each side,
with the inner bark of stock and scion in contact. Have the thick side of the scion outward
(B).

 Keep in mind that the bark of the larger stock is thicker than the scion bark, so the scion
should not be flush with the stock. A very slight tilt will assure a contact, at least where
the cambium layers cross (D).

 There is no need to tie, unless the stock is small and does not bind well. Cover the unions
with grafting compound and be sure the cleft is covered its full length (E).

Figure: Cleft grafting

 Scions that are growing vigorously will need attention to prevent breakage by birds, ice
and storms. Either tie the scion to a supporting brace (see B in figure below), or pinch
back the tips before growth becomes excessive. For additional support, circle all the
shoots from one stub with twine (A).

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 Figure: Caring for cleft graft

Note: Instead of trying to master the whip graft or side graft, use a simple kind of cleft graft on
small understock. Stock (see B) about the same size as the scion (A) may be split and a wedge-
shaped scion inserted.

Figure: Modified cleft graft

c) Side graft
Although the side graft is adapted to a wide range of branch sizes (1/4 to 3/4 inch diameter), its
use is generally restricted to branches that are too large for the whip graft yet not large enough
for the cleft graft. As the name suggests, the scion is inserted into the side of the stock, which is
generally larger in diameter than the scion.

Procedure

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  Select a smooth place on the under stock branch at least a foot from the trunk.
 Make a slanting cut at a narrow angle almost to the pith (core of the branch) (see B in
Figure below). Cut the scion to a short, sharp wedge (about 1 inch) with one side thicker
than the other (see A).
 Bend the branch slightly to open the cut. Press the scion in so the cambium layers of the
stock and scion meet at one side (C).


Figure: Side graft
 Tying is unnecessary if the stock binds well, but you may have to tie small materials if
the scion is not held firmly. Cut surfaces should then be covered with grafting compound
(E).
 In about two weeks, cut off the stock above the union (D) using sharp shears in order to
avoid disturbing the scion. Then cover the cut surface with grafting compound (E).

Reading assignment
Make short notes about bridge graft, splice graft, saddle graft, inarch graft
Some reasons why a graft fails
 The scion and stock were incompatible; apple will not unite with plum, for example.
 The grafting was done in the wrong season.
 The under stock was not healthy.
 The scions were not vigorous.
 The scions were dry or injured by cold temperatures
 The cambium of scion and stock were not meeting properly.
 The scions were upside down.
 The graft was improperly covered with grafting compound.
 The scions were displaced by wind, birds or storms.
 The graft was shaded too much after growth began.
 New growth was damaged by aphids or other insects.
 New growth was killed by fire blight.
 The union girdled because the bindings or label were not released in time.

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D. Budding

This is the art and science of connecting two pieces of living plant tissue together in such a
manner that they will unite and subsequently develop as one plant. It involves inserting the bud
into the root stock till they unit permanently and continue to grow as one plant. The lower part is
called the stock and the upper part is the scion. The root stock is from the local orange and the
scion from the improved variety. Budding is a form of grafting in which a single bud is used as
the scion rather than a section of stem.

Materials and equipment

 Grafting knife/surgical blade.

 Scion
 Rootstock
 Budding tape or Polythene paper.
 Secateurs

Procedure
 Select a healthy rootstock of pencil thickness and a scion from a healthy plant of the
desired variety.
 Remove all the leaves from the scion and keep the scions moist in order to prevent
wilting or drying.
 The common method of budding used in orange propagation is T budding.
 Make a T-cut at about 45 cm from the ground on the root stock.
 The cut should be away from the direct sun rays so as to reduce chances of the bud
drying.
 Loosen the flaps of the bark using the pointed part of the budding knife (open the
cambium).
 Cut out the bud with a very thin slice of wood from the scion (bud stick) as illustrated
below

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  Insert the bud into the prepared cambium on the rootstock (under the two raised flaps)
until the two join and well covered by the flaps on the bark, but the bud it should be
exposed.
 The bud should be fixed facing upwards as illustrated below.

 The bud should be wrapped by tying it completely using a budding tape or ploythene
strip (white pill) to hold the two components together until the union is complete.
 After 3 weeks from the time of budding, the budding tape should be removed.
 If the bud remains green and its edges adhering to the rootstock, then the process is
successful, if the bud looks dry or when the colour has changed brown then the process
has failed, it has to be repeated.
 When the budding is successful, cut of the rootstock about 5cm above the budding joint
(point), this facilitates the bud to grow.
 Remove all the shoot or auxiliary buds and the suckers on the rootstock.

Advantages of buddlings over seed (planting from seed)

Buddlings Seedlings
Fruits with 3-4 years Fruit in 8 years
Purity of variety (the fruits are genetically The fruits usually vary or differ from the
identical and are usually sweet). mother plant
They are resistant to diseases and water They are susceptible to diseases.
logging because the rootstock is hardy.

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Normally produce seedless fruits They produce seeded fruits.
They are less thorny They are more thorny
Produce spreading tree canopy Produce vertical trees.

MANAGEMENT OF TREES IN AGROFORESTRY SYSTEMS

All practices carried out on growing trees to enable the farmer (owner) achieve his/her needs and
expectations are termed tree management. To obtain the desired products and services from an
agroforestry practice, the management of the grown trees and shrubs is important. The common
management activities include coppicing, pruning, pollarding and thinning as well as weeding.
Why tree management
i. To minimize competition with other components in the farm. Trees compete with other
crops for light, space, moisture and nutrients.
ii. To maximize production of desired products like, timber, poles, firewood, fruits etc.
iii. To get the intermediate (by-products) before the final harvest. This ensures provision of
diversified products e.g. stakes, backcloth, fodder, firewood etc.
iv. Agroforestry becomes friendlier with management. Usually farmers are hesitant to
integrate trees on the farm due to their macro consumption nature. Though with
management such attitude is over shadowed and agro forestry becomes friendlier.
v. A well-managed tree grows fast, (pay back in a short period). This pre-empts the
common attitude that trees take long to mature.

Management techniques
(a) Pruning
This is the removal of the unwanted or excess branches and roots. In agroforestry the branches
can also be harvested to provide fodder for the animals. This can be divided into three;
i. Side pruning
This involves reduction of side branches ascending upwards to reduce on water loss, light and
space competition and have a well-shaped, straight stand. Both short term and long term should

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be pruned leaving at least 1/3 of the tree branches. This however, depends on the purpose and the
crop type.
ii. Shoot pruning
The shoot (terminal bud) is removed to on the enable the tree develop more branches. It is
usually carried out on the tree species that provide shed for both animals and crops such as
Polyscias, T. Mantally, Moringa, Cordia etc.
iii. Root pruning
Roots of trees grown together with food crops should be pruned when the trees have grown to
heights of 2-5 m. this should be done at the beginning of the rainy season or at the end of the dry
season.

The spreading roots that feed in less than 2ft deep are reduced leaving the tree to feed mostly on
the tap root. The roots are cut at 0.5-1m from the trunk for long term trees and even less (1-2ft)
for short term trees. Root pruning is done on trees whose roots can compete with companion
crops for water and nutrients.This reduces competition for nutrients and water with companion
crops. Trees feed on leached nutrient and this promotes nutrient recycling. Both short term and
long term trees should be root pruned basing on the field experience. The practice should be
started when the tree is at 1m height to enable it develop deeper roots.

A Pruned Tree

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(b) Trenching
An open trench is cut dug 0.5-1m from the tree trunk in the direction where competitive effects
of the roots are not needed. During this process, all roots in that direction are cut and any re
growth in to this trench is effectively cut off continuously. The trench can either be left open or
covered with soil.

(c) Root barriers

A trench is dug as stipulated above and an iron sheet coated with engine oil is placed to block
any root from penetrating into the crop field.

Other management techniques include;

 Weeding
 Protection
 watering

(d) Coppicing
This is a management practice whereby trees are cut at about knee-height (10-50cm) from the
ground then allowed to grow back. Only trees that can re-grow after cutting can be coppiced.
Such trees include Lusina (Leucaena leucocephala), Calliandra calothyrsus, Nsambya
(Markhania lutea), Kalitunsi (Eucalyptus species) and others. Coppicing should be done towards
the end of the dry season or just at the beginning of a rainy season that the coppiced plants have
the opportunity to re-grow well. (see the diagram below)

How to coppice a tree

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Re-growth from a coppiced tree

Points to remember a bout coppicing

 It is done before field crops are planted, this reduces competition.

 Repeated coppicing is done as needed either when shading of crops is too much or or
when the farmer wishes to harvest branches for fuel wood, fodder, poles etc.
 The cut must be angled and clean and should be done using a sharp instrument.
 Lay down branches on the ground and after shake to remove dried leaves and small
twigs.

(e) Pollarding
This is the removal of the top (crown) of the tree and the top branches (cutting back) to reduce
competition between the trees and the companion crops. The tops of the trees are cut at about 3m
from the base of the tree. Only trees that are known to be able to produce new shoots after
pollarding should be pollarded. Such trees include Avocado (Persea amaricana), Grevillea
(Grevillea robusta), and Mango (Mangifera indica). Trees have special adaptation and can be
able to withstand such shocks as they develop more new branches. The cycle can be repeated
every after a few years perhaps for decades until the farmer harvests it entirely. The leaves from
the pollarded trees can be used as mulch or fodder and the branches can be used as fuelwood.
(check diagram below).
Note:
 Heavy branches can kick back when cut.
 Do not climb trees when wet or slippery.
 Do not allow anyone to stand where a branch can fall on them.
 Learn from more experienced people.

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 A tree before and after pollarding

(f) Thinning
This is the process whereby some of the trees are cut-down with the objective of reducing the
number of trees in a plot so as to enable the vigorous growth of the remaining ones. This is
especially recommended where a commercial woodlot is grown. The starting plant population is
deliberately higher than the expected final plant population, depending on the desired plant
product. E.g. a woodlot can be established and trees spaced at 1m x 1m apart. After some time
the spacing can be increased to 2 x 2m. Firewood and small construction wood are some of the
products that can be obtained from woodlots during thinning.

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 A woodlot before thinning

A woodlot after thinning

(g) Lopping
Some trees especially fruits develop thick canopy that out competes the surrounding crops for
light. Lopping is the cutting of portions of branches from the base of a stem. It involves selective
removal of some of the branches from the tree canopy. This is done to obtain fodder or firewood.
Only small portions of branches can be cut to allow new trees to continue growing well. Tree
species that can be lopped are those that re-grow easily when cut. For example Grevillea
(Grevillea robusta) and Calliandra calothyrsus. Coppiced Calliandra hedge

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TOPIC 4: SOCIO-ECONOMIC ASPECTS OF AGROFORESTRY

Gender Issues in Agro-forestry

Human activity influences complex systems within the natural environment (soil, water, flora,
fauna and air). The human quest to provide goods and services has been accompanied by a series
of environmental problems and conflicts. To address this, regulations and control measures
should be socio-economically acceptable for sustainable management of the natural
environment. Agroforestry will be appreciated and accepted only if it addresses the socio-
economic and environmental issues within the farming households.

Gender
Gender refers to the cultural and social distinctions between men and women. These include the
different attributes, status, roles, responsibilities, opportunities and privileges accorded to women
and men as well as their access to and control over resources and benefits. All these distinctions
can change according to time, place, and the development climate.

Sex roles
These differ from gender roles, in as much as they refer to biological functions that are limited
to one particular sex. For example pregnancy is a female sex role because only women can beer
children.

Gender roles
Roles classified by sex, in which the classification is social and not biological. Child rearing
may be classified as a female role, but it is a female gender role rather than a female sex role, as
child rearing can be done by both men and women.

Socio economic issues affecting adoption of agroforestry

 The land ownership and tenure rights
 Division of labour at household level.
 Traditional and cultural values.
 Preferences and economic choices.
 Sharing of benefits.

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  Power relations and incentives.
 Time available for work.
 Access to resources.
Measures to address the gender issues in agroforestry
 Mobilization of the community to take part in the income generation e.g. agroforestry.
 Sensitization of the community on gender and agricultural development.
 Empowerment of the women to take part in agroforestry e.g. access to financial services
and education.
 Training of the community on the importance of agroforestry.
 Encouraging/involving the women in the decision making process through local
committee membership.
 Ensuring rights to provide assets such as legal status on land ownership, rights to use
common property inheritance.

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