Types Of Irrigation In Agriculture:
The following farming content is about Types of Irrigation in Agriculture.
Introduction To Irrigation
Irrigation is an artificial application of water for the purpose of crop production. Irrigation water is supplied to supplement the water available from,
- Rainfall and
- Contribution of soil moisture from ground water.
In many areas, the amount and timing of rainfall are not adequate to meet the moisture requirement of the crops. Hence irrigation is essential. Scientific management of irrigation water provides best insurance against weather induced fluctuations in total food production.
It is used to assist in the growing of agricultural crops, maintenance of landscapes, and vegetation of disturbed soils in dry areas and during periods of inadequate rainfall.
Scope and Importance of Irrigation
- To supply the moisture essential for plant growth.
- For better utilization of production factors.
- To provide crop insurance against short spells of drought.
- To dilute/washout soluble salts.
- To soften tillage pans.
Disadvantages of irrigation
- The land become alkaline and water logged if excess irrigation water is applied to the land, as a result the land become infertile and barren.
- Excess irrigation water remains into pools on the surface of the ground, will breed mosquitoes, and cause malaria in the nearby areas.
Source of Irrigation
Water for irrigation is obtained from natural streams or rivers, from surface reservoirs and from underground reservoirs. Flood water from rivers is collected in surface reservoirs by constructing dams at suitable sites. Runoff water from small areas can also be collected by constructing ponds or tanks. Water from underground reservoirs is utilized by constructing wells and installing pumps or other water lifts. Water from surface reservoirs is taken through canals. Canals run from higher to lower elevations, and water flows in them by the force of gravity. Based on whether the source of water is above or below the field surface, irrigation is classified into two types:
- Flow irrigation and
- Lift irrigation.
Traditional Methods Of Irrigation
Animal power is abundantly available in India. They are used for lifting of water, besides other field operations and processing works. A pair of bullocks may develop approximately 0.80 horsepower. They can lift water from the depth of 30m or more. Of course the rate of discharge will go down with increase in lift. Some of the devices used for irrigation operated by animal power.
Some of the traditional methods are given below,
- Old Mughal irrigation system.
- Inside a karez tunnel.
- Dam: controls the flow of water.
- Canal: allows the water to be brought to drier areas.
Types of Irrigation – Modern Method Of Irrigation
Depending on soil type slope source of irrigation water, nature of crop methods differs.
Surface Methods Of Irrigation
Surface irrigation is defined as the group of application techniques where water is applied and distributed over the soil surface by gravity. It is by far the most common form of irrigation throughout the world.
- Types of Irrigation – Flooding
When water is applied to the cropland without any preparation of land and without any levees to guide or restrict the flow of water on the field, the method is called ‘uncontrolled’, wild or ‘free’ flooding.
- Flooding generally results in excess irrigation at the inlet region of the field and insufficient.
- Irrigation at the outlet end.
- Efficiency is reduced because of either deep percolation or flowing away of water from the field.
- The advantage of this method is the low initial cost of land preparation.
- Types of Irrigation – Boarder strip
Border strip irrigation is a controlled surface flooding method of applying irrigation water. In this method, the farm is divided into a number of strips. These strips are separated by low levees borders.
- The border strip method is suited to soils of moderately low to moderately high intake rates and low erodibility.
- This method, however, requires preparation of land involving high initial cost.
- Types of Irrigation – Check basin
The check method of irrigation is based on rapid application of irrigation water to a level or nearly level area completely enclosed by dikes. In this method, the entire field is divided into a number of almost levelled plots (compartments) surrounded by levees.
- This method is suitable for a wide range of soils ranging from very permeable to heavy soils.
- Loss of water through deep percolation (near the supply ditch) and surface runoff can be minimised and adequate irrigation of the entire farm can be achieved. Thus, application efficiency is higher for this method.
- There is some loss of cultivable area which is occupied by the levees.
- Types of Irrigation – Ring or basin
This method is a modification of check basin method and is suitable for sparsely grown orchard crops and cucurbits.
- Types of Irrigation – Ridge and furrow
Ridge and furrow is an alternative to flooding the entire land surface is to construct small channels along the primary direction of the movement of water and letting the water flow through these channels which are termed ‘furrows’ or ‘corrugation.
- Ridge and Furrows necessitate the wetting of only about half to one-fifth of the field surface. This reduces the evaporation loss considerably.
- Ridge and Furrows provide better on-farm water management capabilities for most of the surface irrigation conditions, and variable and severe topographical conditions.
- Ridge and Furrow irrigation requires more labour than any other surface irrigation method.
Sub-Surface Methods of Irrigation:
- Types of Irrigation – Sprinkler
In the sprinkler method of irrigation, water is sprayed into the air and allowed to fall on the ground surface somewhat resembling rainfall. The spray is developed by the spray of water under pressure through small orifice or nozzle.
Types of Irrigation – Adaptability of sprinkler irrigation
- It can be used for almost all crops (except rice and jute) and on most soils. It is, however, not usually suitable in very fine textured soils (heavy clay soils) where the infiltration rates are less than about 4 mm per hour.
- The sprinkler irrigation method is particularly suited to sandy soils that have a high infiltration rate. The flexibility of the sprinkler equipment and its efficient control of water application make this method adaptable to most topographic conditions without excessive land preparation.
- It is especially suitable for steep slopes or irregular topography. Land leveling is not essential for irrigation with sprinklers. Soluble fertilizers, herbicides and fungicides can be applied in the irrigation water economically and with little extra equipment.
- Sprinkler irrigation can be used to protect crops against frost and high temperatures that reduce the quantity and quality of harvest. Field supply channels and bunds or ridges are not required.
Types of Irrigation – Advantages of sprinkler irrigation are:
- Elimination of the channels for conveyance, hence no conveyance losses.
- Suitable to all types of soils except heavy clay.
- Suitable for irrigated crops where the plant population for unit area is very high.
- Water saving.
- Higher water application efficiency.
- Increase in yield.
- Mobility of system.
- Saves labour cost, as no bunds are required.
- Areas located at a higher elevation than the source can be irrigated.
- Possibility of using soluble fertilizers and chemicals.
Types of Irrigation – Different types of sprinkler systems
Sprinkler systems are two major types on the basis of the arrangement for spraying irrigation water.
(1) Rotating head or revolving sprinkler system.
(2) Perforated pipe system.
Types of Irrigation – Rotating head:
Small sizes nozzles are placed on riser pipes fixed at uniform intervals along the length of the lateral pipe. The lateral pipes are usually laid on the ground surface. They may also be mounted on posts above the crop height and rotated through 90º, to irrigate a rectangular strip. In rotating type sprinklers, the most common device to rotate the sprinkler head is small hammer activated by a thrust of water striking against a vane connected to it.
Types of Irrigation – Perforated pipe system:
This method consists of drilled holes or nozzles along their length through which water is sprayed under pressure. This system is usually designed for relatively low pressure (1 kg/cm2). The application rate ranges from 1.25 to 5 cm per hr based on pressure and spacing. Based on the portability, sprinklers are classified in following types:
- Portable system: A portable system has portable mainlines, laterals and pumping plant. It is designed to be moved from field to field or to different pump sites in the same field. The portable system may be designed to be moved manually or by mechanical power.
- Semi-portable system: A semi-portable system is similar to a fully portable system except that the location of the water source and pumping plant is fixed. Such a system may be used on more than one field.
- Semi-permanent system: It has portable lateral lines, permanent main lines and sub-mains and a stationary water source and pumping plant. The main lines and submarines are usually buried, with risers for nozzles located at suitable intervals.
- Permanent system: A fully permanent system consists of permanently laid mains, sub main and laterals and a stationary water source and pumping plant. Sprinkler installations in orchards are usually of the permanent type.
Types of Irrigation – Center Pivot Irrigation
It is a form of sprinkler irrigation.
- Consisting of several segments of pipe (usually galvanized steel or aluminum) joined together and supported by trusses.
- Mounted on wheeled towers with sprinklers.
- System moves in a circular pattern.
- These systems are common in parts of the United States where terrain is flat.
- Types of Irrigation – Drip/Trickle Irrigation.
Development of Drip irrigation systems
Drip irrigation is frequent application of water directly on or below the soil surface near the root zone of plants. It is based on the fundamental concepts of irrigating only the root zone of the crop rather than the entire land surface and maintaining the water content of the root zone at near optimum levels. It is one of the latest methods of irrigation, which is becoming increasingly popular in areas with water scarcity and salt problems. It delivers required and measured quantity of water in relatively small amounts slowly to the individual or groups of plants. Water is applied as continuous drops, tiny streams or fine spray through emitters placed along a low-pressure delivery system.
Drip irrigation is a method of watering plants frequently and with a volume of water approaching the consumptive use of the plants, thereby minimizing conventional losses like deep percolation, runoff and soil water evaporation.
In this method, irrigation is accomplished by using small diameter plastic lateral lines with devices called “emitters” or “drippers” at selected spacing to deliver water to the soil surface near the base of the plants. The system applies water slowly to keep the soil moisture within the desired range for plant growth.
Types of Irrigation – Advantages of Drip Irrigation
- Water saving.
- Enhanced plant growth and yield.
- Uniform and better quality of produce.
- Efficient and economic use of fertilizers.
- Less weed growth.
- Suitable to waste lands.
- Possibility of using saline water.
- No soil erosion.
- Flexibility in operation.
- Easy installation.
- Labour saving.
- Suitable to all types of land terrain.
- Save the land as no bunds etc, are required.
- Minimum diseases and pest infestation.
Disadvantages of Drip Irrigation system
- High initial cost of investment.
- Skilled persons are required to operate the machine.
- The water must be relatively clear.
- Poor water distribution efficiency when a low pressure system is installed on steep slopes or uneven lands.