Irrigation in focus as India moves towards driest-ever August

Context: News reports and weather experts say that India might be facing its driest August in 100 years. As of Sunday, India had received 7% less rainfall cumulatively this monsoon compared to the long period average (LPA). This situation is expected to get worse. A recent report in Reuters quotes an India Meteorological Department official saying that. India is expected to receive an average of less than 180 mm of rainfall this August, which is the lowest since records began in 1901.

What is Irrigation?

The process of supplying water to crops by artificial means such as canals, wells, tube-wells, tanks, etc. from the sources of water such as rivers, tanks, ponds, or underground water is called irrigation.

Types of irrigation techniques

1. Surface irrigation: Surface irrigation utilizes gravity flow to move water across land, wetting and infiltrating soil. It encompasses furrow, border strip, and basin irrigation, also known as flood irrigation.
2. Localized irrigation: Localized irrigation involves the distribution of water through a network of pipes, utilizing low pressure, and delivering water in a predetermined pattern to each individual plant or in close proximity to it.
3. Drip irrigation: The technique of delivering water drop by drop at or near the root zone of plants is known as drip irrigation or trickle irrigation. When managed properly, this method can be highly efficient in terms of water usage since it minimizes evaporation and runoff.
4. Sprinkler irrigation: In sprinkler or overhead irrigation, water is piped to one or more central locations within the field and distributed by overhead high-pressure sprinklers or guns. 
5. Sub-irrigation: Sub-surface irrigation also sometimes called seepage irrigation has been used for many years in field crops in areas with high water tables. It is a method of artificially raising water table to allow the soil to be moistened from below the plant root zone.

Why INDIA Needs Irrigation?

• Uneven Rainfall Distribution: While some areas receive heavy rainfall during the monsoon season, others experience long dry periods. Irrigation helps to provide water to crops during dry spells, ensuring consistent and reliable water supply for agricultural activities.
• Agricultural Productivity: Agriculture is a major contributor to India’s economy, employing a significant portion of the population. Irrigation helps increase agricultural productivity by providing water when needed, which is crucial for crop growth, yield improvement, and food security. 
• Drought Mitigation: Irrigation systems help mitigate the impacts of drought by providing water even in dry years.
• Crop Diversification: Irrigation enables farmers to grow a wider variety of crops, including those that are not well-suited to rain-fed conditions. 
• Stabilizing Farm Income: Irrigation helps stabilize farm income by reducing the vulnerability of farmers to the uncertainties of weather patterns. When rainfall is inadequate or erratic, farmers with irrigation systems can still produce crops and generate income.
• Industrial and Economic Growth: Apart from agriculture, water from irrigation sources can be used for various industrial purposes, such as power generation, manufacturing, and other sectors. A stable water supply supports economic growth beyond just the agricultural sector.
• Environmental Conservation: Efficient irrigation practices can help conserve water resources by reducing water wastage and promoting more responsible water use. Modern irrigation techniques such as drip irrigation and sprinkler systems minimize water runoff and evaporation.
• Climate Change Resilience: As climate change brings about shifts in rainfall patterns and increased unpredictability, having a robust irrigation infrastructure becomes even more critical to adapt to changing conditions and ensure food security.

Sources of irrigation

1. Tank irrigation: A tank consists of water storage which has been developed by constructing a small bund of earth or stones built across a stream. The water impounded by the bund is used for irrigation and for other purposes. The tank irrigation is practiced mainly in peninsular India due to the following reasons:
   • The undulating relief and hard rocks make it difficult to dig canals and wells.
   • There is little percolation of rainwater due to hard rock structure and ground water is not available in large quantity.
   • Most of the rivers of this region are seasonal and dry up in the summer season. Therefore, they cannot supply water to canals throughout the year.
   • There are several streams which become torrential during rainy season. The only way to make best use of this water is to impound it by constructing bunds and building tanks.
   • The scattered nature of population and agricultural fields also favors tank irrigation.

2. Wells and Tube wells: A well is a hole dug in the ground to obtain the subsoil water. It is popular in areas where sufficient ground water is available. It accounts for about 16.6% of the net irrigated area in the country. A tube well is a deeper well from which water is lifted with the help of a pumping set operated by an electric motor or a diesel engine.

3. Canals: Canals can be an effective source of irrigation in areas of low-level relief, deep fertile soils, perennial source of water and extensive command area. Canals in India are of two types, viz. (i) Inundation canals, which are taken out from the rivers without any regulating system like weirs. (ii) Perennial canals are those which are taken off from perennial rivers by constructing a barrage across the river. The percentage of canal irrigation in the country is about 23%.

Accelerated Irrigation Benefits Programme (AIBP) 

The programme was launched in 1996-97 to provide assistance to major/medium irrigation projects in the country, with the objective to accelerate implementation of such projects which were beyond resource capability of states or were in advanced stage of completion.

Pradhan Mantri Krishi Sinchayee Yojana (PMKSY)

It was launched in 2015-16 which aimed at enhancing physical access of water on farm and expand cultivable area under assured irrigation, improve on farm water use efficiency, introduce sustainable water conservation practices, etc. 

Objectives:

• Achieve convergence of investments in irrigation at the field level.
• Enhance the physical access of water on the farm and expand cultivable area under assured irrigation.
• Enhance the adoption of precision – irrigation and other water saving technologies.
• Enhance recharge of aquifers and introduce sustainable water conservation practices.
• Ensure the integrated development of rainfed areas using the watershed approach towards soil and water conservation.
• Promote extension activities relating to water harvesting, water management and crop alignment for farmers.
• Attract greater private investments in precision irrigation.

IRRIGATION IN INDIA: 

• According to NITI Aayog, in 2022-23, of the 141 million hectares of gross sown area in the country, nearly 73 million hectares, or 52%, had irrigation access, up from 41% in 2016.
• 8 out of 73 million hectares have the micro irrigation facility
• 40% of the total irrigated area are watered through canal networks, the remaining through groundwater.
• The total potential for micro-irrigation in the country is estimated to be 60 million hectares. 
• Conventional surface irrigation provides only 60% efficiency but drip irrigation has nearly 90% efficiency.
• The country can create irrigation potential in about 60% of its arable land and 40% of the cultivable area will remain dependent on rains because it is not possible to create irrigation networks in certain regions due to hydrological and geographical reasons.

Related concepts & definition:

• Net Area Sown: This represents the total area sown with crops and orchards. Area sown more than once in the same year is counted only once. 
• Gross Cropped Area: This represents the total area sown once and/or more than once in a particular year, i.e. the area is counted as many times as there are sowings in a year. This total area is also known as total cropped area or total area sown. 
• Area Sown more than once: This represents the areas on which crops are cultivated more than once during the agricultural year. This is obtained by deducting Net Area Sown from Gross Cropped Area. 
• Irrigated Area: The area is assumed to be irrigated for cultivation through such sources as canals (Govt. & Private), tanks, tube-wells, other wells and other sources. It is divided into two categories:
  • Net Irrigated Area: It is the area irrigated through any source once in a year for a particular crop. 
  • Total/Gross Irrigated Area: It is the total area under crops, irrigated once and/or more than once in a year. It is counted as many times as the number of times the areas are cropped and irrigated in a year. 
  • Cropping Intensity: It is the ratio of Net Area Sown to the Total Cropped Area.