Irrigation system and importance

Irrigation is defined as the artificial or man-made application of water to soil or land for farming purposes. In other words, irrigation is the artificial application of water to the soil to supplement insufficient rainfall. Irrigation is mainly practicer in areas where there is insufficient rainfall. Water is the most important determinant in the growth of crops. The choice of irrigation system depends on:

Availability of water

For irrigation to operate water must be available in sufficient quantity water should therefore come through Rivers streams and boreholes

Slope of the Land

The choice of irrigation system depends on the shape and slope of the Land while surface irrigation requires sloping land sprinkler irrigation requires a flat land.

Soil type

The choice of any irrigation system depends on the type of soil in the area . Surface irrigation may be effective in a clayey type of soil to aid water running.

Type of crops

The choice of any irrigation system also depends on the type of crops to be grown. While cereals and leguminous crops will require sprinkler irrigation tree crops may require surface irrigation.

Size of farmland

Irrigation system depend on the size of farmland irrigation becomes effective and efficient if the farmland is large.

Cost of irrigation system

Aims of irrigation

1. To add water to the soil in order to supply moisture for plant growth.
2. To ensure the survival of crops during droughts.
3. To cool the soil and the atmosphere there by making the environment more favorable for plant growth.
4. To make early planting possible.

Importance or effects or advantages of irrigation and crop production

The effect of irrigation and crop production are:

1. Irrigation substance the soil for easy tillage operation.
2. It provides moisture in the soil for root absorption
3. It reduces the amount of salt accumulated in the top soil which could be harmful to the crop plants
4. It also cools the soil by reducing the soil temperature during the dry season when they saw temperature is very high. Plant growth is thus improved
5. Irrigation enables the crop to be well established even when rain is erratic.
6. It increases crop production or crop yield.
7. Irrigation provides a humid environment for the breeding of pest and pathogens of crops.
8. It helps in the improvement of microbial decomposition of organic manure to release nutrients for crop plants.
9. Irrigation dissolves nutrients for root absorption.
10. It assists and facilitating crop production all year round.
11. Irrigation encourages the spread of weed seeds.
12. It is used to apply fertilizers.
13. it makes possible two or more croppings within 1 year.

Sources of irrigation water

1. Rivers
2. Streams
3. Voreholes
4. Reservoirs
5. Brooks
6. Lakes
7. Ponds
8. Wells
9. Springs
10. Dams

disadvantages or problems of irrigation

1. High cost of irrigation equipment
2. Increased salinity
3. Disease transmission is possible
4. It leads to build up and spread of pest
5. Vectors of diseases examples snails tsetse flies and mosquitoes may breed in irrigated areas.
6. Movement of farm machineries may be hindered.
7. It may lead to leaching.
8. It may lead to erosion or flooding.
9. It encourages the growth and spread of weeds.

Types of irrigation system

Irrigation systems or types can be grouped into three main classes: surface Irrigation Sub-surface irrigation and overhead irrigation.

Surface irrigation

In this system water from Rivers dams or streams is allowed to flow by gravity along the surface of the Land to farmland. This can be in the form of channels, flooding, contours ditch, basin,furrows, border dyke, border and ditch. The most important condition for surface irrigation to be efficient is for the land to have a gentle slope towards the direction of the farmland.

Advantages

1. It removes excess water caused by heavy rainfall especially in heavy soils.
2. It is easier to construct.
3. Irrigation is cheap to establish and maintain
4. It’s prevents accumulation of alkalis
5. It increases the activities of microbes in the top soil
6. It helps in the collection and disposal of surface runoff.

Disadvantages

1. It cannot be practiced to wear land is hilly
2. It cannot be successful in sandy soil.
3. The volume of water especially in flooding may be difficult to control.
4. Some crops may not tolerate heavy flooding.

Factors to be considered in choosing surface irrigation method

1. The topography or sloppy land .
2. The soil type.
3. The type of crop to be grown.
4. The size of the farmland.

Sub-surface irrigation

In this system water is applied below the soil surface by maintaining an artificial water level at certain depth. This however depends on the type of crop and the nature of the soil. In all cases, perforated pipes are used to deliver water within the soil and this water gets to the root of crops through capillary action.

Advantages

1. By irrigation it is possible to maintain water at optimum depth for crop need.
2. In addition, water use efficiency is high.
3. It also ensures low evaporation losses from soils.
4. It does not create obstruction or obstacles when carrying out cultural practices.

Disadvantages

1. Water which has a high salt content cannot be used.
2. It requires some level of expertise or technical know how.
3. It is a bit expensive

Factors to be considered in choosing subsurface irrigation method

1. The permeability of substratum.
2. the level of water table
3. soil texture or capillarity
4. soil structure

Overhead irrigation

in overhead irrigation system water is supplied to the farmland above the surface of the soil.

Problems associated with overhead irrigation

1. Wind ditorts sprinkler pattern and causes uneven distribution of water.
2. Display force can damage ripening soft fruits.
3. A stable water supply is required for economic use of the equipment.
4. The water must be clean and free of sand debris and large amount of dissolved salt.
5. The initial investment is usually high.
6. Power requirement for pumping water is high.
7. It requires technical know how
8. Literal pipes hinders movement of farm machines.
9. High cost of maintenance or repairs or spare parts not readily available.
10. It can spread diseases.

Overhead irrigation exist in two forms: sprinkler irrigation and drip irrigation

Sprinkler irrigation

In this system water is sprayed from the air and allowed to fall on the ground surface somehow as a rainfall through nozzles under high pressure. A pumping machine which operates under high pressure is needed to pump water into irrigation pipes which are spaced to ensure even distribution of water.

Advantages of sprinkler irrigation

1. The amount of water supplied is regulated.
2. It economises the use of water.
3. It is suitable for high arid lands with high evapo-transpiration rate.
4. Soluble fertilizers and herbicides can be applied through the irrigation water.
5. It can be used for all crops except three crops like cocoa.

Disadvantages of sprinkler irrigation

1. Sprinkler irrigation is costly to operate.
2. High wind velocity may prevent distribution of water.
3. A stable water supply is required
4. It requires high power to produce the high pressure needed to pump water into pipes.
5. There is lack of sufficient technical know how on sprinkler irrigation operation.

Drip irrigation

Drip or trickle irrigation is a new method of irrigation where water is discharged through nozzles called emitters or drippers at selected spacing to deliver water to the soil surface near the base of the plants. With this system loss of water through deep percolation runoff and evaporation is greatly reduced .

Advantages of drip irrigation

1. It is economical in the use of water.
2. It reduces salt concentration in the root zone.
3. Fertilizers can be applied through this system.
4. It operates with slower line pressure.
5. It is the most appropriate system needed in arid and semi-arid areas.

Disadvantages of drip irrigation

1. It is very expensive to set up and maintain.
2. Water cannot be distributed in a sloppy farmland evenly.
3. Water with high salt content cannot be used.

Problems associated with irrigation

There are many problems associated with irrigation and these are

1. Inadequate water supply for irrigation.
2. Irrigation equipments are expensive.
3. Pest from dry surroundings may invade and damage crops in irrigated Land.
4. Disease causing organisms increase with increasing humidity.
5. Vectors of diseases like snails and tsetse flies breed freely in irrigated areas.
6. Irrigation equipment are expensive to maintain.
7. Lack of adequate technical know how on irrigation on the establishment and operations of irrigation scheme.
8. Excessive dissolution of salt in irrigated water prevents proper growth of crops.
9. It may lead to pollution if it contains dangerous chemicals.
10. It disturbs the free movement of farm machinery.

How to reduce disease build up in irrigated farm

reduction of disease build up in an irrigated farm may be achieved through:

1. Use of disease resistant varieties.
2. Crop rotation
3. Use of appropriate chemicals.
4. Use of clean tools.
5. Use of clean or healthy planting materials.
6. Destruction of diseased crop to prevent its spread.
7. Avoidance of excessive irrigation.
8. Weed Control.

Method of irrigating a small nursery

Small nursery can be irrigated through:

1. Manual sprinkling example hand brooms and brushs.
2. Use of watering cans.
3. Drip irrigation.
4. Channel irrigation.
5. Sprinkler irrigation.

Sources of water for irrigation includes Rivers, lakes, streams, ponds, dams, boreholes, Wells and reservoirs.