BLE 211: Principles of
Agriculture and Forestry
Lecture 1
Introduction
Agriculture
 Is the oldest and largest Primary industry.

Is characterised by an integration of farm and
household to produce food and other
products.

Most of the production activities are closely
interrelated as they all utilise labour, land and
capital.
Introduction


The rapidly evolving industrial and
commercial world of today depends on
continued agricultural development to supply
the basic needs of the labour force and for
some raw materials.
Agricultural production takes time and it is
affected by unpredictable natural hazards that
cannot be controlled.
 Thus unlike industry, agriculture cannot
adjust rapidly to changing conditions.
Defining Agriculture

Way of life of rural population where
production is intimately bound to
Consumption

An occupation or profession from which
to derive a livelihood

An industry or business employing
knowledge of the various sciences for the
production of food, feed, fibre and fuel.
Defining Agriculture (Cont.)

Can be regarded as purposeful work
through which the elements of nature are
harnessed to produce plants and animals
to meet human needs. Or

A biological production process that
depends on the growth and development
of selected plants and animals within the
local environment
Evolution of Agriculture

Naturally plants and animals grow and
develop without human influence.
 But agriculture has evolved in response to
human need for increased food production for
a growing population.
 People began to exploit the growth of plants
and animals in order to produce the type and
quantity of food and other products that meet
their requirements.
Importance Of Agriculture

Provision of food for the ever-increasing population.

Provision of jobs in the agricultural industry as for
farmers, crop processors, traders, middlemen and
transporters.

Agricultural products are a major source of
domestic and international trade, which provides
revenue for the Government through taxes.

International export trade in agricultural products
provides the producing countries with the foreign
exchange they need to pay for essential goods
Importance Of Agriculture

Provision of raw materials for the Industries. It is
estimated that the ratio of agricultural raw materials
to non-agricultural raw materials used in industries
is 4:1.

Provision of market for other industries: Agriculture
serves as a large consumer market for industrial
products such as plastic shoes and boots, buckets,
fertilisers, pesticides, agricultural tools and
machinery, building and construction materials,
bicycles, trucks, lorries, tractors, boats and many
others.
Importance Of Agriculture

Education and Training: Many agricultural
education institutions are established to
educate and train people in the science of
agriculture. This provides people with a
career
Agricultural Systems

1.
2.
Two distinct agricultural systems
developed in the tropics following the
initial domestication.
Systems based on plants and
Systems based on animals.
Arable/Plant Based Farming
Systems
Determined by:
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Environmental factors:
Climate
Soil
Natural vegetation
Topography
 Socio-economic

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

factors
Customs
Level of technology attained
Population density
Financial resources available
Family and market demand for food and cash crops.
Categories of Plant Based
Farming Systems

Rain-fed Arable farming Sub-system

Permanent Farming Sub-System
Associated with Swamp Rice Production

Mono-culture of perennial crops
Subsystem
RAIN-FED ARABLE FARMING
SUB-SYSTEM
Consists of :
 Shifting cultivation systems

Semi-permanent cultivation systems

Permanent cultivation systems
Shifting Cultivation
 Involves
leaving land fallow to restore
organic matter, improve soil structure and
siphon nutrients from the subsoil through
the vegetation and leaf fall on the soil.
 Land is cleared, debris burned and crops
are planted on the ash-enriched soil.
 Cropping continues for a period (1-10yrs
but usually 2-4yrs) then land is abandoned
as fallow under regenerating natural
vegetation for some years.
 New area is cleared for cultivation.
Shifting Cultivation
 Usually
land is owned communally with
control powers vested in a chief
exercised on advice of council of elders.
 Individuals have permanent user rights
so long as they continue to use the
land.
 Soil fertility maintained by the bush
fallow.
 No fertilisers or manure are applied:
Little or no use is made of animal dung.
Types of shifting cultivation
 Temporary
 Cultivation
villages shifting cultivation
in the immediate vicinity of their
dwellings until crop yields fall to a certain
level and then the whole community
migrates elsewhere to build a new
temporary villages and open up new land.
Types of shifting cultivation

Permanent villages or towns with their
cultivated and fallow lands covering a large
area around the village.


As the productivity of the land in the immediate
vicinity of the village or town declines, the distance
from the dwelling to the main cultivated area may
become considerable.
Temporary huts are built on the “farm” and
occupied for periods of days or weeks at a time
during the growing season.
Semi-permanent cultivation
systems
 Comprises
modified shifting cultivation
with addition of some other form of land
use on a small part of the holding.
 Results when pressure on land restricts
the cultivator to a limited area within
which to rotate the crop with shortened
bush fallows.
 Forces the family to become
permanently resident on a defined
holding and has de facto, if not
registered, ownership of this land but
may also have user rights in communal
Semi-permanent cultivation
systems
 Some
use of other means of
maintaining fertility to supplement the
shortened bush fallow.
 In the drier areas, farmers may alternate
approximately equal periods of cropping
with grass fallows, the latter being
grazed by stock.
 Cattle and goats are grazed on the
fallows and crop residues, as well as
uncultivable land, and thus contribute
some nutrients to the land in their
droppings.
Semi-permanent cultivation
systems

Small permanent vegetable gardens are
maintained around the houses and in limited
areas of good soil in the valley bottoms.
 Generally under this farming fertility declines
to a low level mainly because the short grass
fallows are unable to maintain it and little use
is made of manure or fertilizers.
Permanent Cultivation
Systems

Have developed where population pressure
has necessitated continuous cropping of
virtually all-cultivatable land.
 Most farmers cannot afford to use inorganic
fertiliser and therefore rely on
 Return of crop residues
 Green manuring
 Use of household refuse and ashes,
 Compost
 Animal manure and
 Other organics such as oil-seed residues
to add nutrients and organic matter to the
soil.
Permanent Cultivation
Systems
The level at which fertility is maintained
depends on:
 Extent to which it is practicable or is
permissible by custom to employ crop
residues, green manuring, and the use
of household refuse, ashes, composts,
animal manure and other organics and
 Energy and skill devoted to the use of
the resources.
Permanent Cultivation
Systems
 Due
to unfavourable conditions fertility
declines considerably.
 Better levels of soil fertility can be
achieved by very high labour inputs by
people with great agricultural knowledge
and skill who have made the utmost use
of all available means of maintaining
fertility
Permanent Cultivation
Systems
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Other methods could include:
Planting various perennial legumes as
restorative crops.
Grow annual legumes as green manures,
for incorporation in the soil in a rotation with
other crops.
Apply well-rotted farmyard manure very
shortly before planting the crop.
Use of compost, which is a partially
decomposed mixture of household refuse,
crop residues, weeds and other waste
vegetable material.
Permanent Cultivation
Systems

Use of other organic manures such as oilseed cakes
 Rotations and mixed cropping. Good
rotations usually give better average yields
than continuous cultivation of the same crop.
Crop mixtures are able to make more efficient
use of the environmental resources of light,
water and nutrients than same crop in pure
stands.
 Fertilizer application
Swamp-rice Based Systems
 Principally
include rice fields embracing
one or more other enterprises that are
either closely integrated with rice
production including:
 Permanent dry-land annual and
perennial crops.
 Livestock.
 Fish culture
Fertility Maintenance

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Use of improved rice varieties
Mechanization of land preparation and
transplanting to save on labour and
increase production per man-hour.
Use of herbicides
Use of fertilizers.
Monoculture

Perennial cash crops are often extensively
grown by small holders as well as on large
company-owned estates.
 They make an enormous economic
contribution.
Monoculture

However their productivity in many of the
older plantations has been low because of:


Use low-yielding, unselected seedlings
Erosion due to lack of adequate soil conservation
measures.
 Low
use of fertilizers which failed to
produce profitable responses from planting
material of low yielding potential.
 Poor cultural practices such as
transplanting, spacing, pruning and shade
management
Monoculture
 With
the use of improved planting
materials, coupled with modern cultural
methods and exploitation, high
productivity levels can be achieved.
Livestock Based System

Determined by:
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The commodity or commodities for sale
The scale of farming operation.
Fall in two broad categories:
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Extensive Livestock production
Intensive Livestock production
Extensive Livestock production

Has two categories
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Nomadic pastoralism
Ranching
Chief reason for nomadism is the seasonal
grazing requirement of the cattle herds and
sheep and goats flocks.
 Ranching not native to tropics but introduced
from Europe and modified to suit tropical
conditions.
Nomadic Pastoralism

Nomadic Pastoralism undergoing various
transitory stages including:
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A seasonal grazing system in which wet and dry
season grazing lands are separately located each
year.
A seasonal grazing system in which the wet and
dry season grazing lands are separated but with
the wet season grazing area permanently located
in one place.
A system involving permanent settlement in the
wet season grazing area.

The problem of the dry season is overcome by
conservation of herbage and growing fodder crops.
Ranching
 Most
of the ranches in tropical Africa,
Asia and Australia are beef ranches, the
cattle being generally the Zebu type but
increasing numbers of crossbred cattle
are being raised on the more
progressive ranches.
Ranching
 Often
the commercial alternative to
nomadic systems of cattle
management.
 Most of the land used for ranching is
either land of low fertility or land of very
low rainfall.
Limiting factors
 Poor
communication
 Lack of good local markets
 Lack of stratification (all operations such
as breeding, rearing and the production
of meat or milk are carried out in the
same holding).
 Marked seasonality in cattle growth and
productivity
Limiting factors
 Low
availability of crop by-products,
forage crops and concentrate feed to
supplement pasture.
 Difficulty in giving individual attention to
ranch stock
 Wild temperament of ranch cattle
 Water shortage
Intensive Livestock Production
 Has
three categories:
Small-Scale mixed farming
 Medium-scale cattle farming and
 Large scale cattle farming.

 Small
Scale Mixed Farming
 Majority
of tropical cattle in the world are
maintained on a traditional system of
small-scale mixed farming or sedentary
subsistence agriculture.
Small Scale Mixed Farming

Many managerial difficulties have hindered
the success of small scale mixed farming
been encountered. These include:
 Small land holdings leading to reduced
field or paddock sizes.
 High cost of fencing
 Lack of productive cattle breeds
 Lack of supplementary and dry-season
feeding.
 Lack of proper housing for livestock
 Traditional milking and calf rearing
procedures.
Medium-Scale Cattle farming
 Comprise
a very small proportion of the
total number of enterprises in the
tropics.
 Though in the Temperate Zone the
majority of the holdings are small, most
of the land is to be found in the
relatively small percentage of the very
large holdings and medium-scale
enterprises
Medium-Scale Cattle farming

Under tropical systems
 Increased population has led to the
subdivision of the large and medium scale
farms into small holdings.
 The laws of inheritance have often
prevented the amalgamation of holdings,
so that instead of farm size increasing, it
has often decreased as the size of the
family has increased.
 Foreign controlled estates were
appropriated by government at
independence and the land reallocated
back to peasant farmers, with the
consequence of land size drastically
reducing
Large-scale cattle farming
 Proportion
of farms falling in this
category is small.
 Large areas of the tropics are suitable
for this form of extensive land use:
 However
due to population growth the
farms have been subdivided.
Large-scale cattle farming
 At
present this potential has relatively
not been exploited, since the fertile soils
of the tropics have tended to be used
for cash crops rather than for grassland
production