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SULPHUR AND ITS COMPOUND SULPHUR AND ITS COMPOUND:A.SULPHUR (S) Sulphur is an element in Group VI(Group 16)of the Periodic table . It has atomic number 16...






Land reclamation is the process of converting wasteland into farm land for growing of crops and keeping of animals while land rehabilitation is the process of restoring land to its former productive state.


  1. Intensify food production to feed the ever increasing population
  2. To overcome land shortage and pressure.

Methods of Land Reclamation


  • Artificial method of supplying water to a region which doest receive adequate rainfall or to ensure continuous crop production.
  • Done in dry areas with low rainfall and regions experiencing dry periods to sustain growth of crops.
  • Dams are used to store water.


  • Can be used for HEP generation
  • For fish farming
  • Supply water for domestic use
  • Control floods.

Negative effects

  1. Can be a cause of deaths by drowning
  2. Breeding ground for mosquitoes which transmit Malaria.
  3. breakage can cause destruction of life and property

Factors Determining the Amount of Water Required for Irrigation

  1. Climate: Areas receiving low rainfall require more water.
  2. Soils: Sandy soils require more water than clays due to low water retention ability.
  3. Crop: Paddy rice requires water logged soils while vegetables require wet and well drained soils.
  4. Size of fields: Small plots require small amounts of water while large plots require large amount of water.

Methods of Irrigation

  • Water lifting method
  • Lifting water from a source by using a bucket or watering can and pouring it on the crops.
  • Used widely in market gardens and on farms adjacent to the water.
  • Flood/basin irrigation
  • Diverting river water into a canal then to plots where it’s flooded.
  • Commonly used in irrigation schemes.
  • Sprinkler or overhead irrigation
  • Taking water to the fields by pipes and applying it on crops by rotating sprinklers mounted on vertical pipes.
  • Used on golf courses and market gardening.
  • Trickle irrigation
  • Plastic pipes with holes laid in the fields through which water trickles to the base of plant.
  • Popular where fruits and flowers are grown.
  • Canal irrigation
  • Directing water through canal to farms.
  • Commonly used in areas experiencing low rainfall e.g. Yatta in Machakos
  • Drip irrigation
  • Inverting bottles filled with water into the roots of a plant.
  • Used in low rainfall areas to grow trees, fruits and flowers.

Drainage of Swamps

  • Process of draining excess water from the land.
  • Problems of land with excess water are:
  1. Is breeding ground for disease causing vectors.
  2. Is water logged and unsuitable for agriculture.
  3. Is prone to flooding which destroys life and property.

Processes Involved

  • Digging ditches for water to ooze into and flow away by gravity
  • Planting eucalyptus which takes up a lot of water e.g. at Kakuzi in Makuyu.
  • Laying perforated pipes in ditches which water will seep into and flow away by gravity.
  • Areas in Kenya with have been reclaimed by draining are:
  • Yala on lower courses of R.Yala
  • Bunyala on lower courses of R.Nzoia.
  • The project was conceived in 1970.

Objectives of the Project of Draining Them

  • Free the area of pests.
  • Prepare land for settlement and agriculture.
  • Ease population on Kano plains.
  • Reduce flooding and associated hazards.
  • Develop the otherwise remote area.


  • Flooding has been controlled.
  • About 800 hectares are available for agriculture and settlement.
  • Water borne diseases have been brought under control.

Control of Pests


  • Fumigation
  • Draining of stagnant water
  • Spraying
  • Clearing of bushes near settlements.

Rodents, birds, squirrels and porcupines

  • trapping
  • poisoning
  • hunting
  • Scaring away

Tsetse flies

  • They thrive in damp areas with high temperatures and prefer bushy vegetation as breeding grounds.
  • Examples of tsetse fly infested areas are Lambwe valley in Kenya and Miombo woodland in Tanzania.
  • The control of tsetse fly at Miombo woodland was aimed at:
  • The control was done by The International Centre for Insect Physiology and Ecology (ICIPE).
  1. Eliminating the pest to obtain land for agriculture.
  2. To treat the sick people and animals to check the spread of resultant diseases.

Measures Taken

Bush Clearing

  • Selective clearing of bushes was applied to prevent soil degradation.
  • Caused tsetse fly to lack a place to breed and killed adult flies and pupae due to low humidity.

Bush Spraying

  • Spraying from the ground or from a low flying aircraft.
  • Doesn’t affect other organisms.


  1. Some insecticides such as DDT have serious environmental effects.
  2. The fly develops resistance and a high dose of chemicals has to be used.
  3. Kills other useful organisms.

Sterilisation males

  • Making the insect unable to reproduce by obstructing its reproductive organs.
  • Luring the male flies to some chemical substance which sterilises them.
  • When they mate with the females fertilisation doesn’t occur which reduces insect population.


  • Square of black cloth coated with glue on which the insects stick.
  • Traps impregnated with insecticides which kills the insects.

Creation of Buffer Zones

Belt of 5 km wide with dense cultivated vegetation to create barrier which the fly couldn’t cross.

Killing of the Hosts

Wild animals which the fly fed were selectively hunted and killed.

Methods of Land Rehabilitation

Afforestation and Reafforestation

  • Improve the productivity of land in the following ways:
    1. Controls soil erosion by:
  • Acting as wind breakers
  • Leaves reduce impact of raindrops on the soil
  • Roots hold/bind the soil particles together.


  1. Vegetation reduces runoff and increases the rate of infiltration of rain water ensuring there is a complete water cycle.
  2. Decayed vegetation provides humus which restores soil fertility.
  3. Roots help moisture to percolate deeply into the ground.
  4. Modifies the climate of an area by moisture being released to the atmosphere causing higher rainfall and lowering the temperature.

Bush Fallowing

  • Cultivating a field for a period of 2-3 years then abandoning it for another so that it may regain fertility naturally by wild vegetation adding humus into the soil.


Grass Strips and Cover Crops

  • Grass and cover crops e.g. sweet potato vines, beans and peas reduce the speed of running water thus helping to check soil erosion.


  • Covering the soil using crop residues or artificial materials such as polythene sheets.
  • Helps to conserve the soil in the following ways:
  1. Reduces evaporation helping to conserve moisture in the soil.
  2. Help to check the speed of running water.
  3. Reduces the splashing effect of rain drops.
  4. Reduces runoff and increases infiltration ensuring more moisture is going to be available for plants growth.
  5. Mulch from crop residues decomposes releasing nutrients into the soil.
  6. Controls weeds.

Application of Manure and Fertilizer

  • Replenishing nutrients depleted from the soil by constant application of manure or chemical fertilizers.

Controlled Grazing

To solve the problem of overgrazing:

  1. The government is advising the farmers through extension officers on the importance of matching the number of livestock with the carrying capacity of land.
  2. Emphasizing on quality than quantity by introducing exotic breeds and cross breeds.
  3. Establishing ranches in livestock farming regions e.g. Kaptuei group ranch.
  4. The land should be subdivided into paddocks so that different sections have time to regain pasture at different intervals.


Filling Quarries

  • Filling the pits with rocks and topping with fertile soils e.g. Bamburi Nature Trail where trees have been planted and animals introduced.

Drainage Trenches

Flooded areas can be rehabilitated by:

  • Digging trenches to drain off excess water to rehabilitate flooded areas.
  • Another method is to construct dams across rivers.

Planting Drought Resistant Crops

  • Planting in Arid and Semi Arid Lands drought resistant and quick maturing crops which take advantage of the short wet season e.g. Pigeon peas, cassava, millet, sorghum, Katumani maize etc.

Irrigation Schemes in Kenya

Mwea Irrigation Scheme

  • Located in Kirinyaga district in central province in Mwea plains on the foot of Mt. Kenya.
  • Started by the colonial government in 1954.


  1. To reclaim the unproductive land from semi-arid conditions.
  2. To occupy detainee labour since Mwea was a detention camp for political detainees during 1952s state of emergency.
  3. To settle former detainees and the landless.
  4. To create employment for former detainees.
  5. To increase agricultural production.

Factors Which Influenced the Location of the Scheme

Physical Factors

  1. Availability of extensive land which made created room for future expansion.
  2. Black cotton soils with high water retention capacities suitable for rice growing.
  3. Freely draining clay loamy soils suitable for growing of other cash and food crops.
  4. Gently sloping land which allows use of tractors and allows water to flow by gravity reducing the cost of pumping it to the fields.
  5. Availability of plenty of water from permanent rivers Thiba and Nyamindi draining the area.
  6. Experiences warm weather during the second part of the year suitable for rice growing.


Human Factors

  1. The land was not inhabited due to its arid conditions therefore there was no displacement of people from the area.
  2. Availability of labour for rice growing to presence of former detainees.
  3. Desire by the colonial government to start a project that could occupy detainees.
  4. Location near major urban centres such as Nairobi, Embu, Nyeri and Kerugoya which provide immediate market for rice.

Irrigation/Cultivation Method Used

  1. Basin irrigation.
  • The ground is levelled.
  • Embankments are constructed.
  • Water to the enclosed sections.
  • The paddy fields are flooded to a depth of 10 cm.
  1. Furrow irrigation.
  • Water flows from irrigation canals to furrow which are in between rows of crops wetting them.

Crops Grown

  1. Wet paddy (rice).
  2. Basmati/Pishori which more valuable.
  3. Sindano which is resistant to diseases.
  4. Subsistence crops e.g. maize, peas and beans in small scale.

Horticultural crops e.g. tomatoes, French beans, melons, etc.

Organization of the Scheme

  • The scheme is divided into Mwea, Thiba, Wamumu and Tebere sections.
  • 6000 hectares are under rice cultivation.
  • Tenants live in 36 small villages.
  • There are 17 primary schools and more than 5secondary schools one of which is for disabled and one mission hospital (Karira).
  • The area under rice cultivation is divided into one acre which is surrounded by a bank of earth (bund) for keeping water within the field.
  • Each tenant is given 4 acres of land and expected to maintain a nursery covering 1/8 of an acre.


Farmers sell rice to local consumers in the urban centres especially Thika and Nairobi.

Benefits of the Scheme

  1. Saving the country foreign exchange by contributing most of Kenya’s rice production.
  2. Providing income to farmers, traders etc. which alleviates poverty and raises the living standards.
  3. Provided land to thousands of landless.
  4. Reservoirs created have helped in controlling flooding.
  5. Improvements of infrastructure as roads have been built to transport rice from the fields to market.
  6. Provision of social amenities such as schools and hospitals which have improved the people’s standard of living.
  7. Provision of employment to many people in farms, local mills and trading.


Problems Facing the Scheme and Possible Solutions

  • Stagnant water has become a breeding ground for mosquitoes and snails which transmit malaria and Bilhazia respectively.
  •  Insecticides should be sprayed on stagnant water to reduce the breeding rate the vectors hence rate of infection.
  • Shortage of water due to excessive droughts and diversion of water into ‘Jua Kali’ rice farms.
  • More reservoirs should be built and farmers should pay a fee to facilitate maintenance of water distribution.
  • Pests and diseases e.g. case warm and leaf miner which attack crops lowering the yields and Quelea birds which feed on rice leading to a major loss of the crop.
  • Using clean planting seeds, burning residues after harvesting and use of explosives to scare birds.
  • Inadequate capital on the part of farmers since the co-operatives collapse making them unable to acquire inputs forcing them to lease out all or part of their farms. The solution is to take politics out of co-operatives so that they can be empowered to supply inputs and credit to farmers.
  • Shortage of labour during the planting and harvesting season which forces the farmers to hire labour from outside at a high cost.
  • Improved marketing by NCPB to resume so that farmers can earn enough money to meet their expenses.

Siltation and growth of weeds in the canals which interferes with the flow of water.

  • Control weeds using chemicals and farmers to avoid cultivating on the river banks.

Inadequate health centres which necessitates travelling for long distances losing many working hours.

Construction of more health centres.

Poor access roads which make transport expensive.

Government to improve the existing roads and construct new ones.

Perkerra Irrigation Scheme

Established in 1954.

Located in Marigat division in Baringo in the RV province.

Aims of Setting up the Scheme

  • To utilize detainee labour.
  • To develop land for agricultural production.
  • To settle the pastoralists as farmers.
  • To control the seasonal floods of R. Perkerra this used to affect the area.
  • To utilise the excess water of R. Perkerra this used to go to waste.


Factors which Influenced the Establishment of the Scheme

Physical Factors

  • Gentle slope of the area which allows mechanisation and flow of water to the fields by gravity.
  • Presence of fertile loamy soil on which a variety of crops can be grown and which also reduces use of fertilizers.
  • Semi arid conditions of the area which necessitated the use of irrigation as the only way to make food production possible.
  • Extensive area of land meaning large scale cultivation of crops was possible.
  1. Perkerra which ensures a constant supply of water for irrigation.

Human Factors

  • Sparse population due to harsh climate which made it easy to establish the scheme.
  • Large population of detainees which required to be occupied in a productive way.
  • Desire of colonial government to start a project to occupy political detainees.

Irrigation/Cultivation Method

  • Ridges and furrows are made.
  • Crops are planted on the ridges.
  • Water is directed to the furrows and allowed to soak slowly.
  • Seed maize is planted in male and female maize lines.
  • From male lines it’s taken for consumption.
  • That from male lines goes for processing.



They grow seed maize for Kenya Seed Company and paw paws are gradually being reintroduced.

Organisation of the Scheme

Management is under NIB which provides infrastructural facilities, accounting and extension services.

Each house hold is allocated 3-4 acres and an additional ½ acre for the homestead.

Farmers are tenants but plans are underway to issue them with title deeds.


  • Seed maize is graded, dried and delivered for shelling.
  • Shelled maize is delivered to Kitale for further processing.
  • The seed is delivered to KSC which pays on delivery.
  • Scheme management pays farmers after deducting the fees for services given.

Achievements of the Scheme

  • Has turned arid land into a productive land.
  • Source of livelihood for farmers and their dependents.
  • Seed maize raises revenue for the government.
  • Has settled previously landless people.
  • Has improved infrastructure and led to provision of social amenities such as schools, shops, electricity, etc.
  • Has created employment opportunities for local people.
  • Source of foreign exchange when sees maize is exported.

Problems of the Scheme and possible solutions

  • Fluctuation of water in R. Perkerra due to droughts and obstruction causing crop stress and reducing the acreage that can be cultivated.
  • Dam construction on the upstream side.
  • Livestock human conflict when farmers go to graze in the region due to attractive vegetation.
  • Solving the conflict through elders.Intense ethnic conflict between Tugen and Jemps tribes because the scheme lies on the Jemps’ land while Tugen are the majority.
  • Government to issue farmers with title deeds.
  • Financial problems causing the farmers to be unable to prepare the land.
  • Start co-operatives to offer affordable credit facilities.
  • Poor transport and communication which hinders production of perishable crops.
  • Government to improve the existing roads and construct new ones.
  • Limited market for products because the surrounding areas are sparsely populated.
  • Transporting produce to distant markets with dense population.

Significance of Irrigation Farming in Kenya

  • Resettlement of landless people e.g. in Mwea.
  • It has made barren land reproductive.
  • Enables farmers to earn an income when they sell farm produce.
  • Provision of employment opportunities which has alleviated poverty and improved the standard of living.
  • Creation of settlement for landless.
  • Earning of foreign exchange by the country after exportation chillies, flowers, peas, fruits, etc.
  • Saves some foreign exchange that would be used to import the entire amount of food needed in the country.
  • Development of infrastructure and social amenities e.g. roads,
  • Promoted industrial development through providing raw materials e.g. rice mills, pineapple processing, sugarcane factories, etc.
  • Has assisted in the control of environmental hazards such as droughts and floods.
  • Has enhanced food security in the country by encouraging growing of food crops such as maize, beans, rice, etc.

Problems Experienced in irrigation Farming in Kenya

Physical Problems

  •  Destruction of crops when excess water goes to the fields causing flooding.
  • Pests and diseases lead to low cotton yields.
  • Inadequate water as a result of catchment areas receiving unreliable rainfall meaning the land can’t be fully utilised.
  • Growth of weeds on furrows and canals causing reduced water flow to the farms.
  • Silting of the canal which prevents water from flowing smoothly to the farms.
  • Sheet erosion resulting from overhead irrigation when practiced on hot dry regions.
  • Salinisation as a result of application of excess water in dry regions.
  • Leaching taking nutrients to the lower horizons where they can’t be accessed by some plants leading to lower yields.

Human Problems

  • Diseases such as Bilhazia and malaria transmitted by vectors living in stagnant water which weaken and even kill farmers.
  • Payment of low prices to the farmers which kills the morale of farmers and sometimes causing them to lease out part or whole of the field.
  • High cost of production making the farmers to sell their produce at high cost meaning the produce can’t compete favourably in the world market since the buyers will prefer cheaper produce.
  • Exhaustion of soil nutrients as a result of continuous cultivation leading to poor yields.
  • Mismanagement of irrigation bodies leading to losses, lack of credit and low prices as each farmer tries to market his or her own crop.
  • Farmers lack the necessary technical advice to enhance their agricultural production as there are very few extension officers.
  • Shortage of labour during planting, weeding and harvesting giving the farmers the burden of hiring labour at high cost.
  • Limited markets as a result of some schemes being located in sparsely populated areas e.g. Perkerra.

Land Reclamation in the Netherlands/Holland

  • Most of coastal land has been reclaimed from the sea.
  • Land reclaimed from the sea and enclosed by walls is called a polder.
  • The work of reclaiming land was done under 2 main projects namely:

Zuider Zee Project

  • Project of Zuider Zee area to the north of Holland.
  • Assignment was given to a Dutch called Cornelius Lely in 1927-1932.
  • Aim was to increase land for cultivation and control further flooding.


  1. Creation of a high dam across the highland of Wierengen and between provinces of N. Holland and Friesland.
  2. Reclamation of 4 polders that would not be affected by rising tides and creation of a fresh water lake from R.Ijsel a tributary of R.Rhine converting the inland tidal sea into L. Ijsel.

Stages in the Reclamation of Land from the Sea in Netherlands

  • Dykes were constructed to protect the land from getting flooded during high tide.
  • Ring canals were constructed to carry water from the area to be reclaimed into the sea.
  • Pumps were installed to pump out water from the area enclosed by dykes.
  • Reeds were sowed to use up excess water.
  • Drainage pipes were laid in ditches to drain water from the water table.
  • The soil was treated with chemicals to lower salinity.
  • Drained land was flushed with fresh water to remove salt from the soil.

Benefits of Zuider Zee Project

  1. Increased arable land by 10%.
  2. Fresh water lakes created provide fresh water for domestic and industrial use.
  3. Ensured better drainage for reclaimed area in the former Zuider Zee.
  4. Reduced the risk of flooding.
  5. Shortened road connection between the provinces of N. Holland and Friesland.

Delta Plan Project

  • Intended to reclaim the S.W region of the country.
  • Involved closing estuaries namely Haringvliet, Brouwersha, Venschegat, Scheldt and Veersche by means of dams.

Benefits of the Delta Plan

  • Controlled pollution and salinisation of inland water.
  • Improvement the soil thus increasing land for agriculture..
  • More recreational lakes created by the newly formed lakes.
  • Fresh water reservoirs created provides S.W region with water for irrigation, domestic and industrial use.

Comparison of Land Reclamation in Kenya and Netherlands


  • In both countries flooding was a common problem.
  • Drainage ditches were used in both countries.
  • Canals were used in both countries.
  • The intention in both countries was to increase land for settlement and agriculture and control flooding.


  • Canals, dams and dykes were used to reclaim land in Netherlands while Kenya used ditches, irrigation, clearing of bushes, etc.
  • In Netherlands land was reclaimed from sea while in Kenya, it was above the sea level.
  • Netherlands had two projects while Kenya had more.
  • In Netherlands it was large scale while in Kenya it was in small scale.
  • In Netherlands it involved use of advanced technology such as dams, dykes, pumping stations etc. while in Kenya it involved less advanced methods such as irrigation, afforestation, clearing of bushes etc.
  • In Netherlands the coastal land was being reclaimed while in Kenya, land distant from the sea was reclaimed.