Different Methods of irrigation | Agristudent.com

Irrigation methods

Different methods of irrigation

What is irrigation?

For details on what is irrigation, please refer our post – What is Irrigation? | Agristudent.com

What are different methods of irrigation?

There are various methods of irrigation which should be followed depending on water avialability, type of land, type of climate etc

 

Irrigation methods

Various methods are given as under

Methods of irrigation

1. Surface Methods of Irrigation

Surface methods

Surface irrigation method means the manner or plan of water application by gravity flow to the cultivated land wetting either the entire field (uncontrolled flooding) or part of the field (furrows, basins, border strips)

Wild flooding

This method is most commonly used for irrigation of crops sown by broadcasting method viz., rice, low value pastures, lawns and millets etc

It consists of applying water to the field without any bunds to guide the flow of water wetting the soil surface completely

Generally it is practiced only when irrigation water is abundant and where land levelling is not followed

Advantages

1. No land levelling & land shaping

2. Low labour and land preparation costs

3. Less skill required by irrigator

Disadvantages

1. Applied water is lost by deep percolation & surface runoff

2. Low irrigation application efficiency

Controlled flooding – Checkbasin

Check basin

This method is most commonly used for irrigating crops like groundnut, finger millet, sorghum, vegetable crops etc.

In this method the field is divided into square or rectangular plots of 4 to 4000 m2 guided by bunds on all the sides

This method is usually practiced in nearly levelled lands, thus no run-off of soil or water takes place and wetting depth is more uniform

However, it is particularly useful on fine textured soils with low permeability rate where it is necessary to hold the water on the surface to secure adequate penetration.

The field channels supply water to each basin, during which the basins are filled to desired depth and water is retained until it infiltrates into the soil

Check basins are also used for leaching salts below the crop root zone depth by percolating water in the reclamation of saline soils

Advantages

1. Water can be applied uniformly

2. Even small streams can be used for irrigation of crops efficiently

3. Simple and cheap when equipment is used for constructing bunds

Disadvantages

1. Unless the land is levelled, distribution of water in plot is uneven

2. Considerable area is lost under field channels and bunds i.e. nearly 30% of area

3. Bunds interfere in working of inter-cultivation equipment

4. More labour is required for field layout and irrigation

Ring basin method

Ring method

This method is a modification of check basin method and is suitable for sparsely grown orchard crops and cucurbits

In this method a circular bund is constructed around each tree/plant or group of plants/trees to create a basin for irrigation

These basins are suitably connected to irrigation conveyance channels is such a way that either each basin is irrigated separately or group of basins by flowing water from one basin to another through inter- connections

Advantages

1. High irrigation application efficiency can be achieved with properly designed system

2. Unskilled labour can be used, as there is no danger of erosion

Disadvantages

1. High labour requirement

2. Bunds restrict use of modern machinery in the field

3. Limited to relatively uniform lands

Border strip method

Border strip method

This method is suitable for irrigating a wide variety of close growing crops such as wheat, barley, groundnut, bajra and berseem

The cultivated field to be irrigated is divided into a number of long parallel strips, generally 5 to 15 m in width and 75 to 300 m in length separated by small border ridges or low dykes of about 15 cm high, laid out in the direction of the slope

The objective is to advance a sheet of water down the narrow strip of land, allowing it to enter the soil as the sheet advances

Irrigation water is released into each strip connected directly to irrigation channel situated at the upstream end of the border strip

After sufficient water has been applied to one strip, the irrigation stream is turned into another strip

A specific requirement in border irrigation is that the longitudinal slope must be uniform, and the transverse slope must be zero or negligible (< 0.03%)

Advantages

1. Large water streams can be used safely

2. Provides uniform wetting of soil profile

3. Low labour requirement

Disadvantages

1. Requires relatively large water streams for quick advance of water to minimize deep percolation losses at the upper end of the border strip

2. Wastage of water by deep percolation in coarse textured soils

Deep furrow method

Furrow irrigation

This method is commonly used for irrigating crops like potato, sugarcane, maize, cotton, melons, sugarbeets and vegetables like lettuce

In furrow method of irrigation, the flat bed surface is converted into a series of ridges and furrows running down the slope

The spacing of the furrow is ordinarily determined by the spacing of row crop

The length of the furrow and slope depends on several factors viz., texture, intake rate etc.

Depending on the soil, crop spacing, farm equipment used etc spacing between furrows varies from 60 to 120 cm

Depending on the soil texture furrow length ranges from 20 to 300 m or even more

To avoid overtopping and scouring problems, furrow inflow rates are normally limited to 2 to 15 m3/hr/furrow

Slope along the furrows may range from 0.2 to 2%. Where the land is too slopy (>5%), the furrows must be constructed on contours.

Among the various surface irrigation methods, there is a relative saving of water in furrow method, hence efficient use of water is possible by this method

When furrow irrigation is practiced under saline and alkaline conditions, the lateral movement of soil moisture coupled with evaporation causes salt to accumulate in the ridges between furrows.

Advantages

1. Fairly high irrigation application efficiency among surface irrigation methods

2. Furrows serve as field drains in areas of heavy rainfall

3. Low evaporation losses

Disadvantages

1. Not suitable in coarse textured soils with high infiltration rates

2. Possibility of intra-furrow soil erosion

3. Labour intensive

Corrugations

Corrugations

This is a special method of furrow irrigation

Corrugations or rills are shallow furrows running down the slope from head ditches or laterals, which are sometimes very close to each other

This method is used for irrigating close growing crops, which do not require inter-culture operations and may also be used in conjunction with border irrigation

Corrugations are often used in fine textured soils that take water slowly and in soils, which tend to seal over and crust when flooded

2. Sub-surface irrigation

Sub surface irrigation system

Sub-irrigation is the method of applying water beneath the soil surface; close to the plant roots so that either water seeps from the sides of the channels towards the plant roots or through capillary movement upward

It is usually done by creating an artificial water surface at some pre-determined depth, about 30 – 75 cm below the ground, depending upon the texture and rooting characteristics of the crop

Application efficiencies vary from 30-80% depending upon conditions

Water having high salt content cannot be used

This method is expensive, difficult to maintain and operate, and suitable only for few crops

Because of high investment required, it has not been widely adopted in India

3. Sprinkler irrigation method

For details, refer our post on sprinkler irrigation – What is Sprinkler irrigation? | Agristudent.com

4. Drip irrigation method

For details on drip irrigation method, refer our post – What is Drip irrigation? | Agristudent.com

Further readings and references

Handbook of agriculture

http://wikipedia.com

 

Author: agristudent

Team Agristudent is a young and dynamic team of Agriculture specialists who have acquired specialised knowledge in their respective subjects. Their mission is to create a unique online encyclopedia of agriculture, which can be useful to millions around the world as an online reference library

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