agro forestry strategy

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AGROFORESTRY STRATEGIES FOR LANDDEGRADATION REDUCTION AND

SUSTAINABLE PRODUCTION

BY

FIDELIS AWEVER TISEER (Ph.D)

Department of Biological Sciences,Ahmadu Bello University, Zaria

[email protected] .

mailto:[email protected]

mailto:[email protected]



AGRO FORESTRY STRATEGY FOR LAND DEGRADATION

REDUCTION AND SUSTAINABLE PRODUCTION

INTRODUCTION

Land is defined by FAO (2006), as a delineable area of the

earth’s biosphere, an ecosystem with its soil, water resources (both

terrain and near surface ground reserves), ground surface vegetation,

animals and crops, human settlement pattern and the physical result

of past and present human activities such as terracing, water storage,

drainage structure, infrastructure and buildings.

Land degradation has become an issue the world over. Concerns

over biodiversity decline, water scarcity and human migration and

conflicts are all pointers to one and the same issue. The answers to

these may lie in part from evolution of sustainable production systems,

agro forestry being a credible candidate in the bioresources realm.

Agro forestry as a term is relatively new to the Researchers in

the English sphere, having been adopted from French to English

around 1960. It has since kindled interest in various groups that

research in earth’s sciences with consequently several concepts and

definitions. The practice of agro forestry is however not new

particularly to remote agrarian civilizations that evolved culturally

compliant ways of land management before elitist systematic

approaches.

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To anchor this discourse however, I like to adopt the definition

drawn up by the International Council for Research in Agro Forestry

(ICRAF) with task among which is to set precise definitions of terms

that will guide systematic approaches on the subject. The ICRAF

submitted that “Agro forestry is a collective term for systems

and technologies of land use where perennial woody plants

(Trees, bushes, shrubs, and by assimilation, palms and

bamboos) are deliberately cultivated on ground otherwise

used for crops and/or stock rearing in a spatial or temporal

arrangement, and where there are interactions at once

ecological and economic between the woody plants and the

other components of the system”. The interactions of course could

be positive or negative and may not remain stable in time.

THE ECOLOGICAL CONSEQUENCES OF AGROFORESTRY

SYSTEMS

Declining woody plant cover all over the Nigerian landscape and

particularly on arable lands has elicited or aggravated the;

Decline in soil fertility

Decline in water resources and soil moisture conservation

Increase in soil erosion

Decline in food and feed resources

Decline in biodiversity

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Increase in human migration and communal conflicts

WOODY PLANT COVER AND SOIL FERTILITY

Woody perennials generally have deep root systems which

extract soil nutrients from deep lying soil horizons and deposit these

on the top soil in the form of organic matter through litter droppings.

The mineralization of this litter improves soil structure, releases

mineral elements at the plow zone where annual crop roots can access

them.

The organic matter improves soil aggregates, crumb structure

and soil pore spaces. The effect is percolation of precipitation and

water availability to the root zones of the crops. Fertilizer mobility in

the soil is enhanced and thus improved returns per application results.

Other agroforestry woody trees particularly reduce the amount of

fertilizer requirement per unit area of farm. These are the nitrogen

fixing trees such as Leuceana Leucocephala, Gliricidia sepium and

Milletia thonningii Pterocarpus erinaceus Erythrina senegalensis among

others. Possibly, zonal relatives in this family of trees such as

Lonchocarpus laxiflorus could have the same properties and need to be

investigated. Generally tree roots will prevent or slow down the rate of

soil erosion which wears away top nutrient rich soils.

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While problems of land exhaustion is general of villages in the

South Eastern border of Yankari Game Reserve (Alkaleri Local

Government), soil erosion is particularly serious around

A. Futuk area in the following villages;

Garin Wambal

Wala kerol

Sabon Gari

Alkalerin Kwana

B. Yalo area

Alkalerin Gwana

Digare

C. Mansur Area

Jadan Mansur

Bogga

The indigenes in these villages had ideas compliant with known

agroforestry objective. The woody plants accommodated on their

farms for obvious benefits were;

Scientific Name Hausa Name UsesParkia Clappertoniana Dorowa Soup condimentButrypermum paradoxum Kadanya Mai Kadanya/fruits Afzelia Africana Kawo Edible oil

Cordia Africana Aliliba Sweetner

While these plants have disappeared due to over exploitation for

fuel, artisanal uses and others, the people are willing to reestablish

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them using Taungya method. Other woody species that can help with

the problems are;

Jatropha curcas (Bindazugu); used as a farm demarcation shrub.

A good population of this on the edges of farms helps deter

grazing animals and encourages bees which could be exploited

for honey production.

Scientific Name Hausa Name UsesFaiherbia albida Gawo Animal fodder

Soil nitrogenLonchocarpus laxiflorus Halshen saa/farin sansamii “

Leuceana leucocepha “Gliridia sepuim “Sesbania sesbans “

These are multipurpose woody species that can improve soil

quality and fertility, provide fodder for livestock, fuel for fires and

insurance against wind erosions.

WOODY PLANT COVER AND WATER ECONOMY

A densely woody area causes evaporation of rain water from the

plant surfaces. This increases atmospheric humidity, generating the

cloud that accounts for the next day’s rain. Without the tree cover,

most of the water will enter stream channels or infiltrate resulting in

progressive drying of the air. Also the trees intercept the water from

the rains and release same gradually from stem flow or leaf drips. This

way the soil is much wetter for a longer period in fairly woody areas

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than in bare grounds. Direct evaporation from the ground surface is

also reduced in fairly woody areas. This way plant cover enhances soil

water retention. This makes the accompanying crops enjoy moisture

longer than crops where woody plant have completely been removed.

Deforestation in a watershed could cause other problems such as

stream bank erosion, flooding and disturbance of fish habitats. These

reduce the overall production very significantly. Floods in several parts

of Northern Nigerian are in a way due to massive deforestation in

these regions.

AGROFORESTRY PRACTICES AND SOIL EROSION

Soil is eroded by either rain water or excessive wind.

Agroforestry practices reduce the impact of rain drop, intercept rains

and redistribute rain water in a residual manner. Woody plants on

farms also act as wind breaks. Wind breaks on farms in drier areas can

be achieved by the use of multipurpose trees such as;

Scientific Name Hausa Name UsesTamarindus indica Tsamia Food/feedHyphaene thebiaca Goruba Food/raw material for

making roofs etcMilletia thonningii Tuburku Feeds and N fixationBalanites aegyptica Aduwa Food and feed

Parkia clappertoninia Dorowa Food and feed

The qualities of trees suited for these environments must be;

Drought resistance

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Adaptability to soil

Tolerance of salinity

Resistance of wind, browsing, pest and diseases

Rapid and regular growth

Little development of creeping roots

Production of wood, forage; fruits etc

AGROFORESTRY, FOOD AND FEED PRODUCTION

Multipurpose agroforestry woody plants have cultural medicinal,

food and feed values.

The following woody plants directly provide food for man;

Scientific Name Hausa Name UsesMangifera indiica Mangoro Food/shelterParkia clappertoniana Dorowa Food/feed/shelterMoringa oleifera Zogale Food and medicine

Balanites aegyptiaca Aduwa FoodPhoenix dactylifera Dabino foodBatryspermum paradoxum Kadanya Food and medicine Adansonia digitata Kuka Food and feed

Others such as Faidherbia albida, Acacia Senegal, Leuceana

leucocephala, Gliricidia sepium, milletia thonningii are excellent

browse plants for ruminants in feed stress periods.

Besides these agroforestry trees increase habitat availability for

wild game.

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WOODY PLANTS AND BIODIVERSITY

Plants generally provide habitats for other forms of fauna. This

increases the biodiversity of places that are appreciably wooded. The

consequences are favourable for crops in ways that may not be too

apparent. These include;

Healthy population of pollinators

Integrated farming approaches such as apiculture and crop

husbandry

Rearing of Guinea fowls and Franckolins

WOODY PERENNIALS, CROP PEST AND DESERTIFICATION

Woody plants such as Jatropha curcas act as trap crops which

protect the arable crops from insect damage. Plants in this category

must be unpalatable by the potential pest. This way agroforestry

reduces over dependence on chemical pesticides that are harmful to

the environment.

Desertification is a progressive diminution or destruction of the

biological potentials of the land that leads to desert-like conditions.

This must be distinguished from desertization (desertilized) and should

be recognized as a process that can occur any where. Overall erosion

of biological potentials of the land at the ecosystem level starts with

elimination of perennial woody species on an area and other things

depending on these follow. Consequences include;

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Increased albedo

Increased wind speed/erosion

Removal of top soil

Scurring of young plants by wind blown sand.

Excessive temperatures etc

WOODY PLANTS, HUMAN MIGRATION AND COMMUNITY

CONFLICTS

UNEP (1999), stressed that civil strife, inter communal conflicts

are mainly predicated on land issues. Very frequently there are clashes

between Herdsmen and sedentary farmers due to forage and crop

damages. Even within communities, people who keep ruminants as

secondary enterprises besides farming often have conflicts with others

for crop residue and outright crop damaged. Agroforestry particularly

the use of multipurpose trees on arable farms can incorporate animal

husbandry and crop farming.

Other issues such as human migration are caused by irreversible

soil degradation due to nutrient depletion, erosion and crop failures.

Agroforestry trees can enhance nutrient rejuvenation, soil moisture

retention, soil erosion control hence preserve agricultural soils.

Migration such as this is affecting areas in South Eastern Bauchi State

around the Mansur area.

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TYPES OF AGROFORESTRY

1. Alley cropping – food crops are grown in alleys of fast growing

leguminous trees such as Gliricidia sepium, Leucaeana

leucocophala etc where livestock production is incorporated, it is

called Alley Farming Systems.

The trees may need to be pruned at a point to encourage crop growth.

However where Faidherbia albida (Gawo) is used such a problem does

not exist.

2. Shelter Belt: woody plants are sued as hedge rows to shield

crops from wind throw, scurrying damage from wind borne sand.

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Fig.1: Alley Cropping



Trees that can be used here include Afzelia africana, Spondias

monbim, Prosopis africana, Parkia clappertoniana, Jatropha curcas.

Hedge rows can also serve as trap plants against pest.

3. Scattered Farm Forestry: a minimum number of 20 – 30

woody trees on a hectare of farm prevents excessive

evaporation from the soil, rejuvenates soil fertility among other

things already mentioned.

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Fig.2: Shelter Belt Hedge Row



4.

Silvi Pastoral System: Here woody plants in a fuel wood

lot are spaced to accommodate grass/herbaceous pastures on

which ruminants are grazed.

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Fig.3: Scattered Farm Forestry

Fig.4: Silvi Pastoral System



Trees like Azadiracta indica, Eucalytus camaldulensis etc can be

used. Others are Newbouldia laevis, cassia siamea etc.

5. Agrosilvi Pastoral: This entails allowing livestock on a piece of

land after the crop has been removed. The field held crops and

trees previously. It optimizes the use of a piece of land.

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Fig. 5: Agrosilvi Pastoral

agro forestry strategy

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