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Form 1 Agriculture Notes on Water Supply, Irrigation and Drainage
Grade/Class: Form 1
Term: Select Term
Document Type: PDF
WATER SUPPLY, IRRIGATION & DRAINAGE
What is irrigation?
By the end of the lesson you should be able to;
* define irrigation
* explain the importance of irrigation
* describe the methods of irrigation
* list the equipments and facilities used in irrigation
* explain the maintenance practices carried out on irrigation equipment and facilities
* appreciate a crop grown through irrigation
* explain the importance of drainage
* describe the methods of drainage.
The areas covered in this lesson includes:-
* Application of water to plants
* Importance of irrigation
* Methods of irrigation
* Advantages and disadvantages of various methods of irrigation
* Equipment and facilities of irrigation
* Maintenance on irrigation equipment and facilities
* Physical properties of soil
* Importance of drainage
* Methods of drainage
Irrigation Schemes in Kenya
what is irrigation?
Application of water to plants by man is referred to as irrigation
Importance of irrigation
Why is irrigation necessary?
Irrigation is necessary to reclaim arid and semi arid land Irrigation is needed to supplement rainfall.
Irrigation provides enough water for growth of plants which require flooding e.g. paddy rice.
METHODS OF IRRIGATION
During dry periods irrigation can be used to supplement rainfall in supplying sufficient moisture to crops.
The following is a list of methods used in applying water to plants.
Use of sprinkler
Overhead irrigation in coffee crop
Flooding the farm with water
Use of a watering can
Use of furrows
(i.) Subsurface irrigation involves application of water to plants under the soil surface (ii.) Artificial application of water to plants in form of rain from above is called overhead irrigation
(iii.) Sluice gate is a barrier put along a canal to control the flow of water during flood irrigation
Equipments and facilities used in irrigation.
Pivot irrigation system popular in large scale farming Maintenance practice of irrigation facilities
Maintenance skills are required to ensure irrigation facilities are working
Importance of drainage
* To increase soil aeration around the root zone for proper g,
* To increase soil volume near the root zone,
* To raise soil temperature for better plant growth,
* To reduce soil erosion by increased infiltration rate,
* To increase microbial activity which improve soil structure and make plant food readily available.
Effects of poor drainage
Methods of drainage
Planting eucalyptus tree
By use of underground drain pipes
By use of:-
* Open ditches
* Cambered beds
* French drains
Use of water pumps
WATER SUPPLY, IRRIGATION AND DRAINAGE
This is the study of how water is supplied and used in the farm
This topic will be covered in two lessons as shown below
* WATER SUPPLY AND WATER POLLUTION
* IRRIGATION AND DRAINAGE
Study how this community is using water
Introduction to water supply and pollution
Water supply is the provision of water for use in the farm, from various sources e.g. rivers, lakes among others.
Water pollution is the process which makes water harmful to living organism.
A good example is water containing chemicals and microorganisms being used in the farm.
Why do farmers boil water from rivers before drinking?
WATER SUPPLY AND POLLUTION
1) Cultivation along the river banks: - This opens the river banks to erosion making the water dirty. It is a government policy that when cultivating near a river a strip of 15m should be left with vegetation.
2) Planting trees: - Trees control soil erosion and so they help to keep the water clean and prevent sedimentation of the rivers.
3) Controlling weeds using herbicides: - Herbicides are toxic chemicals which when washed into the river makes the water poisonous
4) Overgrazing: - This lead to soil erosion. Water run-off from an overgrazed area finds its way into the river, polluting the water.
5 ) Fertilizer application:- When fertilizers are applied into the soil they dissolve and drain into the water sources
6 ) Ridging:- Controls soil erosion and prevents water pollution
Methods of Water Conveyance
(i) Using canals:-Canals are used to convey water for irrigation and livestock , water flows through the canals using gravitational force therefore they carry water from higher areas to lower areas
(ii) Using animals :-Water is put into containers such as drums, jerry cans, buckets and others. These water containers are carried by animals, animal pulled carts.(iii) Using vehicles:- Water in containers such as tanks can be carried by large trucks or lories to where it is required
(iv) Using hose pipes:- Hose pipes are commonly used where tapped water is available .they are used to convey water from the tap to where it is to be used. Hose pipes are best used for irrigation.
(v) Using humans:- Water in containers can be carried by people on the head or the backs
Weir constructed across a river
1) Visit a water source. Find out how water is conveyed from the source to the area of use
2) Identify polluted water body. Find out methods used to prevent water pollution
3) Participate in a water pollution control exercise
4) Visit a water treatment plant. Note the various stages and chemicals used in water treatment
PUMPING OF WATER
By the end of the lesson, you should be able to; * state the sources of water for the farm
* describe water collection, storage, pumping and conveyance of water
* describe water treatment and explain its importance
* demonstrate an appreciation for clean water in farming and life in general.
Sources of water.
Spring: - natural source of less contaminated water
Rivers and streams
Rivers and streams:-originating from a water catchments area
Wells: - are holes dug in the ground until the water table is reached
Lakes: - huge collection of water on land depression which are fed by rivers, streams, springs and rain
Boreholes:-deep holes drilled into the ground by the use of machines
Rain water: - can be collected and stored in tanks or ponds for later use
USES OF WATER
Uses of water on the farm.
Irrigation of crops
List of the uses of water on the farm.
1 ) Diluting agrochemicals
2 ) Mixing concrete with water
3 ) Cooking food
4 ) Watering livestock irrigation
5 ) Cooling engines
WATER COLLECTION AND STORAGE
Dams, weirs and tanks store water collected during rainy season for use during dry season.
Drainage pipe:-Allows water to flow out of the tank during cleaning
Overflow pipe:-Allows excess water to flow out of the tank
Gutter:-Collects rain water from the roof
Inlet pipe:-Allows water to flow into the tank
Outlet pipe:-Allows water to flow out when water is being drawn
There are several types of water pumps used in the farm
* Reciprocating pump
* Centrifugal pump
* Rotary pump
* Hydram among others
Parts of a hydram pump
Air chamber:- ensures continuous flow of water out of the pump
Delivery bulb:- prevents water from flowing back from the air chamber to the valve box
Impulse valve:- Creates high pressure of water within the valve box
Delivery pipe:-Allows the water to pass out of the pump
Ways through which water is moved from one point to another
Canals are used to convey water for irrigation and livestock, water flows through the canals using gravitational force therefore they carry water from higher areas to lower areas
Water is put into containers such as drums, jerry cans, buckets and others. These water containers are carried by animals, or animal pulled carts.
Using a hose pipe
Hose pipes are commonly used where tapped water is available .they are used to convey water from the tap to where it is to be used. Hose pipes are best used for irrigation.
Water in containers can be carried by people on the head or the backs
Water in containers such as tanks can be carried by large trucks or lories to where it is required
Agricultural practices that may contribute to water pollution;
Cultivation along the river banks
This opens the river banks to erosion making the water dirty. It is a government policy that when cultivating near a river a strip of 15m should be left with vegetation. Controlling weeds using herbicides
Herbicides are toxic chemicals which when washed into the river makes the water poisonous
This lead to soil erosion. Water run off from an overgrazed area finds its way into the river, polluting the water.
When fertilizers are applied into the soil they dissolve and drain into the water sources
Prevention of water pollution by planting trees
Trees control soil erosion and so they help to keep the water clean and prevent sedimentation of the rivers.
Stages in water treatment system
Filtration at the intake
Removes the insoluble particles from the water
Water mixed with soda ash (sodium bicarbonate) for softening and alum (Aluminium sulphate) helps to coagulate solid particles
Removes magnesium and calcium ions thereby making water to foam easily with soap
Coagulation and Sedimentation
Allows solid particles to settle down making water clear
Filtration tank with layers of gravel and fine sand. Removes the insoluble solid particles from the water Chlorination controlled by a doser Adds chlorine solutions which kills pathogens (micro-organisms)
Keeps water in good condition before use
Apart from chemical water treatment, another method of treating water is boiling.
Importance of treating water
* To kill disease causing micro-organisms such as cholera, typhoid bacteria and bilharzias worms that thrive in dirty water.
* Remove chemical impurities such as excess fluoride
* Remove bad smell and taste
* Remove sediments of solid particles
IRRIGATION AND DRAINAGE
Application of water to plants
In the previous lesson you covered sources and uses of water in the farm.
Plants require water for all the life processes such as photosynthesis,
respiration and transpiration so as to give good quality and quantity produce. Plants water requirement varies from one type to another and is also dependent
on other factors such as stages of growth, physiological, morphology and prevailing weather conditions.
1. IRRIGATION: - process of supplying water to crops artificially
2. SURFACE IRRIGATION:-process of supplying water to plants where water is allowed to flow on the land surface
3. SUBSURFACE IRRIGATION:-process where water is available from under the soil surface using perforated pipes
4. OVERHEAD IRRIGATION:-process where water is availed to crops from above.
5. PADDY RICE:-rice growing in a leveled ground flooded with water
6. DYKES AND LEVEES:-earth embankment enclosing water in a level ground
7. SLUICE GATE: - earth barriers put along the canal the flow of water
8. RECLAIM LAND:-make land useful for agricultural production
9. FOLIAR FERTILIZER: - a type of application of fertilizer to be absorbed through the leaves of the plant.
10. WATER SUPPLY;-Is the provision of water for use in the farm
11. HYDROLOGICAL CYCLE:-is the circulation of water from the earth’s surface to the atmosphere and then back to the earth’s surface
12. WEIR:-is a barrier constructed across the river to raise the water level and still allow the water to flow over it
13. DAM:-is a barrier constructed across a river or a dry valley to hold water and raise its level to form a reservoir
14. PUMPING WATER:- Is the lifting of water from one point to another by use of mechanical force
15. CENTRIFUGAL FORCE:-is a force away from the centre
16. ROTARY MOTION:-Movement that goes round
17. RECIPROCATING MOTION:-Movement that goes back and forth .
18. WATERING ANIMAL:-Giving animal water to drink
19. DRAINAGE: process of removing excess water or lowering the water table from waterlogged area.
20. FRENCH DRAIN:-Are ditches dug, filled with stones and gravel and then covered with soil
21. CAMBERED BEDS :- Are raised and flattened earth embankments constructed on water logged areas.
1) Conduct a practical where you participate in carrying out different methods of irrigation applicable in the school. Divide the learners in groups so that they each group carries out a different method of irrigation as follows:
Group I -irrigate the flower beds using watering cans
Group II –irrigate the school lawns using water hose pipe
Group III – connect the water hose to a sprinkler and use it to irrigate the vegetable garden
2) After the practical allow each group to make a presentation of their activity to others concerning:
i) The difficulties encountered
(ii.) Water control
(iii.) Efficiency of the method used
3) As the learners carry out the practical assess the work as follows:
a) Quantity of water applied-5marks
b) Degree of root exposure-5marks
c) Degree of erosion- 5 marks
d) Water wastage-5marks
TEACHERS TIPS ON DRAINAGE
1) Make a field trip to a nearby waterlogged place for the learners to observe the following:
a) Type of plants growing in the waterlogged area
b) Type of plants growing around the waterlogged areas
- The learners should compare the appearance of the plants in the waterlogged area and those growing on dry land
- The learners should give the most practical give the most practical ways of draining water from this area
2) Find out whether the learners have listed the following plants
(i.) Plants growing in the waterlogged areas;- Arrow roots
- Water hyacinth
- Water reeds
(ii.) Plants growing around waterlogged areas
- Water cabbage
- Nut grass
3) Conclude the trip by making a statement that most of those plants growing in a waterlogged area are not useful to the farmer and therefore the need for drainage.
Functions of stir-up pump parts
1 . Handle- it is the one held when plumbing
2 . Air vessel- sucking in air to create vacuum
3 . Leg and foot-stepping on to support the pump while pumping
4 . Barrel- allow the movement of the piston up and dow
5 . Foot and valve strainer-suck in and sieve the liquid
6 . Delivery hose-delivers the liquid from the gland to the trigger control unit
7 . Lance handle-held by hand to direct the spray liquid to the target
8 . Trigger control- opened and closed to control the outlet of the spray liquid.