Introduction to Irrigation Methods:- What is irrigation? well, it is a process of providing controlled amounts of water to plants, agriculture crops, orchards, landscapes etc..at required intervals. Irrigation comes into picture during dry periods or when there are no rains in the region. Irrigation also helps from frost conditions other than weed control (in growing grain crops) and prevents soil consolidation as well. If the agriculture crops are grown with direct rain-fall, it is referred as a rain-fed crop. So there are two options to grow crops; Irrigation and Rain-fed. Apart from growing green crops, irrigation is also being used for dust suppression, cooling livestock (dairy, goats, sheep, pigs, etc..) from heat, sewage disposing, and in a mining area.
Irrigation plays a major role in any agriculture crop growing. One should be aware of different types of irrigation adapted in orchards or crop growing to become a successful farmer. You can choose the appropriate irrigation methods based on soil type, the layout of the field and water availability. There are mainly 2 categories of irrigation; Traditional Irrigational methods and modern irrigation methods.
In this write-up, let us discuss different types of irrigation methods along with their adaptations, advantages, and disadvantages.
Irrigation Methods – Types of Irrigation Methods:- There are many Irrigation methods available to adapt based on soil, crop type, water availability and method of planting.
Irrigation Methods- Surface irrigation (Traditional Irrigation):- This type of irrigation old and most popular irrigation methods used in most of the countries since centuries. Surface irrigation covers 4 types of variations to supply the water.
- Flooding Method.
- Borderstrip or Bed Method.
- Basin Method.
- Furrow Method.
Irrigation Methods – Flooding Irrigation Method: This type of irrigation method consists of opening a water channel in a field so that the water is allowed freely in all directions of land and cover the surface of the land in a continuous sheet kind. This method is the most inefficient method of irrigation as only about 20 to 25% of the water is actually used by plants or crops. The rest of the water would be lost as a runoff, seepage, and evaporation. In this method, water distribution is uneven and you cannot expect uniform crop growth. you can adapt this method in case of uneven lands where the cost of levelling is high and regions where an abundant supply of water is available. This method of irrigation is not suitable for agriculture crops that are sensitive to water-logging conditions. This method of watering suitable where broadcast crops, particularly peas, small grains, green pastures, and alfalfa are grown as major crops.
Where can we adapt Flooding Method: This type of irrigation method is applied in situations like
- Regions where plenty of water source is available
- Best for high-density crops.
- Where soil erosion is less.
- Soils that are permeable.
- If the land is with irregular topography.
- Regions where a water source is cheap and affordable.
Benefits and Advantages of Flooding Method: The following are advantages of flooding method.
- Shallow soils are best fit for this method.
- This method is useful if the land required extensive levelling.
- Set up cost and operation costs are less when compared to other methods.
- This method is safe from all livestock and does not interfere with any other cultivation activities.
Disadvantages of Flooding Method: The following are disadvantages of flooding method.
- There is a huge loss of water in this method.
- This will cause excessive soil erosion on steep lands or fields.
- There will be a manures and fertilizer loss due to an erosion of the soil.
- This method encourages weed growth.
Irrigation Methods – Bed or Borderstrip Irrigation Method: In this technique, the field is levelled and divided into little beds/strips surrounded by bunds of 20 cm to 30 cm high. Little irrigation channels should be provided between 2 adjoining rows of beds. For high-value plants or crops, the beds might be still smaller especially where water is pricey and not so abundant. This procedure is adaptable to many soil textures except sandy soils and is suitable for high-value plants. It requires levelled soil or field for uniform water distribution. This method provides a more effective way of uniform application of water in the field. This method is suitable for plants in lines or sown by broadcast method. This method requires more initial investment and less labour. You can expect less maintenance in this type of irrigation.
Where can we adapt this method: The following conditions favor this method of irrigation.
- Where abundant water is available.
- Good to implement in Sandy Loam, loams and clay soil textures
- Soils should be deep enough at least of 80 cm.
- Good to implement for high-density orchards or closely cultivated crops.
Benefits and Advantages of Bed Irrigation Method:
- With this method, more area can be brought under cultivation with a lesser expenditure.
- This method of irrigation requires less labour.
- This method of irrigation causes lesser erosion when compared to flood irrigation.
Disadvantages or Bed irrigation Method: The following are some of the disadvantages of this method.
- This method of irrigation is not ideal for all types of plants/crops.
- In this method, uniform or balanced supply of water is tough.
- This method of irrigation is not ideal for all soil textures.
- This method also requires fairly abundant water supply.
- Land must be levelled for uniform water distribution.
- The initial cost of this method is expensive as it requires land levelling.
- Water drainage should be provided in this method.
Irrigation Methods – Basin Irrigation Method: This irrigation technique is much more suited to horticulture crops/orchids. In this technique, a raised platform known as ‘Thanvla’ is shaped around trees or bushes and they’re connected to one another through drains and the water reaches from one tree to another. This process is not suitable for crops.
This method of irrigation is suitable in which the size of this plot to be irrigated is tiny. The basin could be square, rectangular or circular form based on planting method. Ring and basin is widely used for irrigating fruit trees. A little causeway (bund) of 15 cm to 24 cm high is shaped around the stump of plants/ trees with a distance of approximately 30 cm to 60 cm to maintain the soil dry. The height of the outer bund varies depending on the water depth required /recommended to retain. Basin irrigation additionally requires levelled soil rather than suitable for all kinds of soil. It is also efficient in using water however its initial price is high.
There are lots of variations in its usage, but all involve dividing the field into smaller unit regions so that each includes a virtually flat surface. Bunds or ridges are built around the regions forming basins within which the irrigation water could be controlled.
Where can we adapt Basin Irrigation Method: This method can be adapted to high-value crops, smooth topography areas, all kinds of soil textures, and high water requirement plants/orchids.
Benefits and Advantages of Basin Irrigation: Possible advantages of Basin Irrigation are provided here.
- With this method, varying supply of water is possible.
- This method saves time and rapid irrigation is possible. Once the water is started, it can reach other trees automatically.
- There won’t be any water loss by run-off.
- There won’t be any manure/fertilizer loss because of soil erosion is not expected.
- This method is economically viable due to less investment.
- More trees get benefited with this irrigation method.
Disadvantages of Basin Irrigation Method: Possible disadvantages of Basin Irrigation are given below.
- This method of irrigation is not suitable for all crops mainly useful for horticulture crops.
- Some wastage of water is done in this method.
- This method of irrigation may encourage to spread the diseases in trees.
- If the land is not levelled, expect the initial cost to go high.
- This irrigation process is not suitable for soils that disperse easily and readily form a crust.
Irrigation Methods – Furrow Irrigation Method: Furrow irrigation process is resorted to where plants are one developed in rows. Across the side of rows of plants, ‘Dol’is shaped, and in between 2 such ‘Dols’, a furrow is formed in which water flows for irrigation. The quantity of stream of water is dependent upon the demand for water from plants and also the rate of infiltration.
Row crops like cotton, sugarcane, potatoes, vegetables could be irrigated by furrow technique. It is suitable for cluttered lands in which the furrows are created along contours. The length of the furrow is determined largely by soil permeability. In sandy and clay loams, the length is more than in clay and clay loams. Water doesn’t come in contact with the plant stalks. On slopes of 1 to 3 percent, furrow irrigation with straight furrows is quite profitable. But on steeper slopes contour furrows, not just check erosion but guarantee uniform water penetration. Within the furrow irrigation, the following methods are used depending on the situation.
- Sloppy Furrow method.
- Levelled Furrow method.
- Contour Furrow method.
- Serial Furrow method.
- Corrugated Furrow method.
Furrow Irrigation Method Advantages: Expect the following benefits using this method.
- This method provides a facility to irrigate large areas at a time.
- These irrigation methods can be adapted in most of the soil textures.
- Very easy to use in any crops with row planting method.
- This irrigation system is easy to install and maintain,
- This method saves labour since once the furrow is filled, it is not necessary to give water a second time.
- This method is a comparatively cheaper method when compared to other above-mentioned types.
- This method provides enough quantity of water to the plants.
Furrow Irrigation Method Disadvantages: The possible disadvantages of Furrow Irrigation are given below.
- Due to the imbalance in the flow of water, wastage of water is possible with this method.
- Furrow irrigation is not ideal for all types of crops.
- Skilled labour is required to manage this.
- Water drainage must be provided.
- Wastage of water is possible due to an imbalance in the flow of water.
- There is a risk of underground salts coming up to the soil surface layer because of excessive water filling.
Irrigation Methods – Subsurface Irrigation Method:- Subsurface irrigation or sub-irrigation may be natural or artificial. Natural subsurface irrigation is possible in which an impervious layer exists under the root zone. Water is permitted into series of ditches dug up to the impervious coating, which then moves laterally and also wets root zone.
In artificial subsurface irrigation, perforated or porous pipes have been laid out underground below the root zone and water is directed into the pipes with suitable means. The system involves initial high price, but maintenance is very cheap. There is a risk of soil getting saline or alkaline and neighboring soil ruined due to heavy seepage.
It is very efficient in using water as evaporation is cut away almost completely. The plant roots don’t suffer from logging, there is absolutely no reduction of agricultural property in laying out irrigation method and implements may be worked out openly. This method of irrigation is very rare in India and used in other parts of the world.
Irrigation Methods – Drip or Trickle Irrigation Method (Modern Irrigation Method):- A recently developed irrigation system known as drip irrigation also known as “Trickle Irrigation” originally developed in Israel, is becoming popular in areas of water scarcity. In this irrigation system, a little bit of water is applied at regular intervals in the form of water droplets through nozzles connected to tubes spread over the soil to irrigate a limited area around the plant.
A precise amount of water equivalent to the daily consumptive use or the depleted soil water needs to be applied. The soil water could be maintained in the field capacity during the crop growing period. Deep percolation losses could be completely prevented and the evaporation loss is also decreased.
The application of water and piping systems needs to be designed according to the type of plants, topography and weather conditions typical to the geographical area.
The basic equipment for drip irrigation consists of a water supply head, the main pipe, lateral pipes, and drippers. The water leak in the pipe system is controlled with control valves and fertilizers can be applied at the water resource. As water moves through the very small sockets of drippers, it is filtered until this distributed in the pipe system.
Advantages of Drip Irrigation Method: Expect the following advantages of drip irrigation system.
- You can expect minimal water loss in the drip system.
- Using this method, you can control the amount of water and intervals to be applied at plant root zone or base.
- The drip irrigation system enables applying water fertilizers at an optimum rate to the plant root zone.
- The drip system can check the weed growth at plant base apart from maintaining a low moisture tension in the soil.
Disadvantages of Drip System: There are some disadvantages of the drip system.
- Well, The initial cost of the commercial drip irrigation is high. However, most of the state governments and some central schemes are providing drip system subsidies and loans. The cost of the unit/acre depends mainly on the spacing of the crop or plants. For widely spaced crops like fruit orchards, the system is more economical than sprinkler irrigation system.
Irrigation Methods – Sprinkler Irrigation (or) Overhead irrigation (Modern irrigation Method):- This method consists of the application of water to soil in the kind of a spray, somewhat as rain. It is particularly useful for sandy soils because they absorb water too fast. Soils that are too shallow, too intense or rolling could be irrigated efficiently with sprinklers.
This method is suitable for regions having uneven topography and in which erosion hazards are somewhat high.
In sprinkler irrigation, water is conveyed under pressure through pipes to the area to be irrigated where it is passed out through or sprinklers. A centrifugal pump may be used for suction lift up to 37 to 50 cm. A piston type pump is preferable in which water is extremely deep. The pipe consists of two sections, the main line, as well as the laterals.
The main line might be permanently buried underground or might be laid above ground if it is to be utilized on quite a few fields. The main pipes are usually made of steel or iron.
The laterals are lightweight aluminum pipes and are usually portable. The sprinkler nozzles could be single or double, revolving or stationery and mounted or riser pipes attached to the riser. Each sprinkler head applies water to a circular area whose diameter depends upon the size of the water, which varies in 0.25 (1/4) to 0.75 (3/4) inch/ hour is determined by selecting the correct combination of sprinkler nozzles.
The main parts of sprinkler system are;
- Power generator.
Where can we adapt the Sprinkler Irrigation?
- In case of uneven topography.
- Shallow soil texture.
- High density or closely cultivated crops.
Advantages of Sprinkler Irrigation: Expect the following benefits of sprinkler irrigation method.
- Sprinkler system provides uniform distribution of water across the crop.
- You can implement this system in most kinds of soil textures.
- Nutrients and fertilizers can be evenly applied through sprinklers system. This is can be carried out by drawing liquid fertilizers slowly into the sprinkler pipes on the suction side of the pump so that the time of application varies from 15 to 30 minutes.
- You can expect less water loss in this system.
- You can bring more area under cultivation.
- This system does not require land levelling
- The output of water from sprinkler can be controlled according to crop requirement or plants growth.
Sprinkler irrigation Disadvantages: Expect the following disadvantages of this method.
- The initial set up cost is very high.
- This may cause to increase your power bill.
- In case of high winds, the distribution pattern may be disturbed, reducing spread or increasing application rate near the lateral pipe.
- You may get problems with clogged nozzles, this requires frequent checks and maintenance.
- The cost of operations and maintenance is very high in sprinkler irrigation.
- This irrigation method is suitable for high-value crops only.
Irrigation Methods – Pot irrigation Method:- Pot irrigation procedure is much more suitable for regions having scanty rainfall. In saline areas where flow irrigation is not suited, bud irrigation procedure is successful. An earthen pitcher is utilized in this method. The pitcher is fixed on the floor up to the throat.
Holes are made in the pitcher and water is filled with it so that seepage of water through the pockets keeps the nearby soil moist. Water is filled in these pitchers at regular intervals.
Advantages and Disadvantages of Pot Irrigation Method:
- In this technique, only the place near the pot becomes irrigated and not the entire place.
- In this method, water seepage below the ground is also in minimum quantity.
- It is the best method for horticulture crops and vegetable growing.
- Once the pitchers are fixed, irrigation could be done for 6 years, which reduces expenditure.
- This does not require technical knowledge
- With this method, Irrigation in this technique is possible in a limited area.
- This technique requires clean water because unclean water could cause congestion of minor holes, which would not be able to provide moisture any longer.