BLE 211: Principles of Agriculture and Forestry

Lecture 1

IntroductionAgriculture 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 Two distinct agricultural systems

developed in the tropics following the initial domestication.

1. Systems based on plants and

2. Systems based on animals.

Arable/Plant Based Farming Systems

Determined by: Environmental factors: Climate Soil Natural vegetation Topography

Socio-economic 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 CultivationUsually 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 villages shifting cultivation 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 grazing land.

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 SystemsDue 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 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 oil-

seed 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 SystemsPrincipally 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 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

MonocultureWith the use of improved planting

materials, coupled with modern cultural methods and exploitation, high productivity levels can be achieved.

Livestock Based System Determined by:

The commodity or commodities for sale The scale of farming operation.

Fall in two broad categories: Extensive Livestock production Intensive Livestock production

Extensive Livestock production Has two categories

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: 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 factorsPoor communicationLack of good local marketsLack 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 cattleWater shortage

Intensive Livestock ProductionHas 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 farmingComprise 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 farmingProportion 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 farmingAt 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