Adaptation of Modern Irrigation Method Amid Water Shortage

Majority of the wheat area is irrigated through flood or the basin irrigation method which has 30–50% irrigation efficiency.

Adaptation of Modern Irrigation Method Amid Water Shortage

Agriculture sector employs about 42.3% of the labor force and adds about 19.5% to the GDP (gross domestic product) of Pakistan. The total cultivated area is 22.12 million hectares, and out of this, 19.23 million hectares are being irrigated through several sources.

In Pakistan, 5.96 million hectares are irrigated through canals, whereas the rest of 8.15, 3.71 and 0.65 million hectares are irrigated through canal tube wells, rainfall and wells.

Wheat which is a major essential food crop, planted on more than 9.22 million hectares during 2015–16 contributed 1.9% to GDP. Wheat is generally planted by the broadcast method during rabi season in irrigated areas of Pakistan, and drill sowing is minimal.

Irrigated wheat covers 8-million-hectare area that accounted for 85% of the total wheat area with an average productivity of 3.0t/ha. In Pakistan, water availability in the normal year for rabi season was around 36.9 MAF.

During the last decade (2007–08 to 2016–17) water availability for rabi season was 5–45% lower in comparison with the normal year. In canal-irrigated areas, farmers get fixed turn time to irrigate crop once in a week which is not enough to irrigate their whole cropped area, and generally rely on either tube well water or rainfall.

Majority of the wheat area is irrigated through flood or the basin irrigation method which has 30–50% irrigation efficiency.

Because of uncertainty and limited water availability at severe growth stages, farmers tend to apply too much water to the wheat crop when available, which also affects the wheat growth negatively.

Availability of water is reducing, and there is a need to adopt water-saving techniques. For this purpose, following techniques can be adopted.

Bench Terraces

Bench terraces are measures used on inclined land with relatively deep soils to retain water and control erosion. They are normally constructed by cutting and filling to produce a series of level steps or benches. This allows water to penetrate slowly into the soil.

Bench terraces are reinforced by retaining banks of soil or stone on the forward edges. This practice is typical for rice-based cropping systems. It has following benefits

  • Controls soil and water runoff and erosion.
  • Decreases slope length. Every 2-3 meters of slope length is levelled to terraces.
  • The speed of water running down the slope is greatly reduced.
  • Improves soil productivity over the long run.

Micro Irrigation

It is the technique in which low volume of water is applied at low pressure and high frequency. Irrigation interval is ranged 1 to 4 days. The system has widespread network of pipes operated at low pressure. At pre-determined spacing exits are provided for the release water generally known as emitters.

In Micro / Drip Irrigation, water and fertilizers are applied through a network of UV resistant pipes and standardized emitters (dripper, Micro sprinklers), at a defined flow rate, close to plant roots on plant requirement basis. Therefore, the soil near the roots is always kept at “field capacity” which enables the crop to easily capture the required water and nutrients, and grow healthier.

As water is applied so close to the plants that it reaches only the area of the soil necessary to feed the roots.  Micro / Drip Irrigation, as compare to other traditional methods, inhibit the moisturizing of whole soil profile which results in saving of water, leaching and evaporation.

In Micro / Drip irrigation water will be applied in small quantity on a high frequency basis (daily) to maintain optimal moisture level in soil in which the plant can flourish. By adapting this method. we can save about 40-60% water.

Furrow-Irrigated

It is raised bed technology one of the efficient irrigation methods in which water moves in furrow, and crop is planted on raised beds. In the Yaqui Valley of Mexico, farmers have shifted to a bed and furrow system for wheat planting due to shortage of water.

The technique resulted improvement in irrigation and nutrient management, in saving water, better crop stands, lower seed rate and reduction in space.

Integration of short duration mung bean crop in the maize-wheat system on permanent beds enhanced the system productivity by 29%, net returns by 38%, and water productivity by 24% compared to the conventional system.

In Pakistan, wheat sown on 70cm bed and furrow system in the rice-wheat area of Punjab produced good yields due to better spike length, number of grains per spike.

Wheat is planted after rice/cotton/sugarcane/maize in Pakistan. Presence of previous crop residue hampers, tillage and seeding operations for wheat. This had a negative effect on adoption of drill and bed planting techniques which results that majority of farmers are forced to plant wheat through the broadcast method with heavy tillage.

In ridge-furrow planting of maize and cotton, ridge and furrows formed with a ridger and cotton or maize planted manually on the top or the side of the ridge increased germination and yield of cotton in comparison with flat planting and is widely practiced in Pakistan.

Ridge planting was evaluated in comparison with bed planting and drill sowing, and 17–24% higher wheat yield was observed with bed panting in comparison with the conventional method of broadcasting. Raised bed and ridge sowing methods of wheat planting saved 22% irrigation water over flat sowing.

Sprinkler Irrigation

It is similar to natural rainfall. Water is scattered into the air and irrigate entire soil surface through spray heads so that it breaks up into small water drops spreading over the ground.

Sprinklers irrigation method provide efficient coverage for small to large areas and are suitable for wide range of crops and are adaptable to nearly all type of soils because they are available in a wide range of discharge capacity.

Sprinkler system are designed to ensure maximum water saving, combining high quality, affordability and ease of installation. Components are essentially made of high strength & chemically resistant engineering plastics to achieve functional satisfaction and favorable cost economics.

Pivot Irrigation

In this irrigation method sprinklers are placed along a series of bowed pipes which is pivoted at one end, and moved around the field in a circular fashion.

Central pivot irrigation is a form of sprinkler irrigation consisting of several segments of pipe joined together and supported by strings, mounted on wheeled towers with sprinklers which are positioned along its length.

The system moves in a circular pattern and is fed with water from the pivot point at the center of the circle. The outside set of wheels sets the master pace for the rotation. Centre pivots will cover surface in relation with the number of curves and supporting tower up to 500m in length.

Crops may be planted in straight rows or sometimes in circles to conform to the travel of the center pivot in crops. Movement of each tower is secured by either hydraulically driven systems or electric motor-driven systems mounted at each tower, and specific type dimension can be fitted to specific soil profile.

Educated farmers with sizable land holding and tube well are the initial adopter of modern irrigation method and technology because of its simplicity and availability. Switching from flood irrigation system to sprinklers, pivot and drip irrigation systems helps the agricultural sector to save a tremendous amount of water every year. When combined with better soil management practices such as no-till or limited tillage and mulching more efficient irrigation systems can significantly reduce water usage.

Muhammad Adnan

Muhammad Adnan

I am professionally qualified as agronomist and studying MSc. (Hons.) agronomy at College of Agriculture, University of Sargodha, Pakistan and focusing on plant nutrition and weed management. I Completed my B.Sc. (Hons.) in agriculture in 2018 from University of Sargodha.

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