New Technology Irrigation System

Introduction

One Prominent part of agriculture that can be used with technological innovation to increase efficiency and effectiveness is irrigation. There is continuously growing population, rapid infringement of agricultural land. And, there is increasing need of more food and water to sustain humanity. As a result of the present situation, there is a need of smart, innovative agricultural practices than ever. Technology is already aiding agriculture in innumerable ways.

Irrigation is the method in which artificially a controlled amount of the water is supplied to plants at regular intervals for agriculture. It is used to assist in the growing of agricultural products, maintenance of landscapes, and re-vegetation of disturbed soils in dry areas and during the periods of inadequate rainfall. Irrigation has been a central feature of agriculture for over 5,000 years and is the product of many cultures. Historically, it was the basis for economies and societies across the globe, from Asia to the other continents. Irrigated agriculture is an indispensable part of the nation’s economy. Irrigation also supports the livestock and poultry production through irrigated animal forage and feed crops.

The key to a sustainable agriculture looking to the future is in water use, and it is clear that the current standards in place are much too wasteful to rely on. Lack of appropriate and affordable irrigation technologies geared towards poor farmers on small plots is a major constraint to the spread of irrigation. Mostly the irrigation system used in Nepal is conventional surface (flood) irrigation method, which does not allow to adequately distribute the resource among all the farm lands. This unsustainable water uses is affecting the agriculture production and thus quality of life.
Local farmer based irrigation system has historical remarks in Nepalese livelihood. Government’s Project “Chandra Nahar Construction” in 1985 BS is the first advanced irrigation system in Nepal’s History. Now, government of Nepal has a policy to develop and amplify the use of different types of irrigation system like surface and subsurface irrigation system, lift irrigation system, new technology based irrigation system to facilitate the irrigation water throughout the year. Government of Nepal is practicing the multipurpose Inter Basin Water Transfer Projects, Reservoir based irrigation Projects. Government of Nepal is facilitating the policy of integrated water resources management to utilize the available water to enhance the agricultural products by integrating the small scale irrigation system.

Most irrigation equipment used in conventional pressurised irrigation systems in Nepal is imported and costly. So that the farmers have to pay higher prices for equipment. To address these problems, therefore, appropriate technologies need to be identified and adapted to suit smallholder farmers

The new technology irrigation system is an option that improves the quality of life of small farmers. Among the many daily challenges faced in traditional irrigation system are soil erosion and crop losses. In this context, the sustainable farming modernization projects, which promotes more efficient water uses among farmers through localized irrigation infrastructure and training can be recognised as new technology irrigation system. New technology irrigation system can be described in following irrigation schemes:

Drip irrigation System

Drip (trickle) Irrigation system is the latest field irrigation techniques, and is meant for adoption at places where there, exists acute scarcity of irrigation water and other salt problems. In this method, the water is slowly and directly applied to the root zone of the plants, thereby minimising the loss by evaporation and percolation. This systems involves the laying of head, mains, sub-mains, laterals and drop nozzle. The systems distribute water through a network of valves, pipes, tubing, and emitters. The head consists of a pump to lift water, so as to produce the desired pressure of about 2.5 atmosphere, for ensuring the proper flow of the water through the system. Depending on how well designed, installed, maintained, and operated it is, a drip irrigation system can be more efficient (90% efficiency) than other types of irrigation systems, such as surface irrigation or sprinkler irrigation.

The drip irrigation system uses well controlled operating manuals and helps to refining the seed growth. It doesn’t make any types of soil erosion due to flow of the water. However it is very costly system than any other systems and requires high skilled manpower for design, installation and operation. In this system the salinity gets unsafe. Also it faces the problem of the moisture distribution.

Sprinkler Irrigation System

In Sprinkler (Overhead) Irrigation, water is supplied in the form of a spray through a network of pipes and pumps. In this system water is piped to one or more central locations within the field and distributed by overhead high-pressure sprinklers or guns. It is a kind of artificial rain in a controlled manner and therefore, gives very good results. It can be used for all types of soils and for widely different topographies and slopes. The correct design and efficient operation are very important for the success of this method. The perpendicular pipes, having rotating nozzles on top, are joined to the main pipeline at regular intervals. When water is pressurized through the main pipe it escapes from the rotating nozzles. It gets sprinkled on the crop. The sediments and debris are very harmful for the sprinkler equipment.

The system useful in irregular topography, in land with permeable soils and erodible lands with steep slope. However, it is expensive system and requires high skilled manpower for design, installation and operation. The system can achieve 80% efficiency and is less labour oriented. This method prevents water logging especially at high water table areas. The system avoids surface runoff.

Lift Irrigation System

Lift irrigation technology is based on new technology in the context of Nepal. It is used when there is water availability in lower elevation than the command area. This scheme must accomplish two main tasks: first, to carry water by means of pumps or other ways, from the water source to the main delivery chamber or reservoir tank, which is situated at the top most point of the command area. The second task is to distribute the lifted water from reservoir to the field of the farmers by means of suitable and proper distribution networks. Mainly the distribution system works by pressure flow due to gravity alone.

In the most prevalent system, the area under irrigation is divided into different blocks according to topography determined by contour plan. The water requirement for each block is determined, and pipe lines are designed for these blocks depending on the available head and required discharge. Field delivery chambers are then constructed on the distribution pipe lines, and valves are fitted to control the flow of the pipe lines, with flow from the main delivery chamber controlled by these valves. In this system, lines for lower fields have more discharge, because the force of gravity is greater, so water distribution can be unequal.

Subsurface Irrigation System

Subsurface (Sub-irrigation) irrigation system also known as seepage irrigation, is a method of irrigation where water is delivered to soils directly under the surface. The moisture reaches to the plant roots through capillary action. The excess may be collected for reuse. Sub-irrigation is used in growing field crops such as tomatoes, peppers, and sugar cane in areas with high water tables such as Florida and in commercial greenhouse operations.

In subsurface irrigation method, water is distributed in a series of ditches about 0.6 to 0.9 metre deep and 0.3 metre wide having vertical sides. These ditches are spaced 45 to 90 metre apart.

Sometimes, when soil conditions are favourable for the production of cash crops (i.e. high-priced crops) on small areas, a pipe distribution system is placed in the soil well below the surface. This method of applying water is known as artificial sub-irrigation. Soils which permit free lateral movement of water, rapid capillary movement in the root-zone soil, and very slow downward movement of water in the subsoil are very suitable for artificial sub-irrigation. The cost of such methods is very high. However the water consumption is as low as one-third of the surface irrigation methods. The yield also improves. Application efficiency generally varies between 30 and 80%.

References:

1. AgriTechTomorrow, https://www.agritechtomorrow.com
2. New Irrigation Tehnologies, Isaya V. Sijali and Rose A. Okumu
3. Department of Water Resources and Irrigation, Irrigation Policy, 2070, Nepal
4. The Word Bank Group
5. Comprehensive subjective guide book of civil Engineering
6. Wikipedia Encyclopaedia