Micro-irrigation and groundwater use

Agriculture the largest consumer of groundwater in India

Agriculture consumes the largest share of groundwater in India - the biggest user of groundwater in the world. The past few decades have witnessed an alarming depletion of groundwater resources in the country. While almost half of the agricultural area cultivating food grains in India depends on irrigation, as high as 65 percent of these irrigated land holdings depend on groundwater to meet their water needs.

Inefficient use of groundwater exacerbates the problem

While borewells and tubewells continue to suck groundwater for agricultural use at alarming rates, putting the current consumption at as high as 84 percent of the total water available in the country, this withdrawn water continues to be used inefficiently. The conventional flood method of irrigation (FMI) still used by farmers in the country is highly inefficient, where water is allowed to flow in the field and seep into the soil.

This results in wastage of water, since excess water flows off the surface without being utilised. This has led to India using 2 to 3 times more water than what major agricultural countries like China, Brazil and the US use to produce one unit of food crop.

Micro-irrigation, proposed as a solution to groundwater depletion

It has been recommended that farmers should move from flood irrigation to drip or sprinkler irrigation systems (micro- irrigation). This will help in conserving water as well as save on the cost of irrigation. Using such micro-irrigation systems has also been linked to an increase in the yield of crops.

At present only about nine million hectares of area in India is under micro irrigation, of which drip irrigation covers about four million hectares of the area, when the actual potential for micro irrigation in the country is about 70 million hectares.

Micro irrigation is known to vastly reduce the amount of water needed for irrigating crops. For example, sprinkler irrigation uses 30 to 40 percent less water, while drip irrigation uses about 40 to 60 percent less water as compared to flood irrigation. There is a 40 to 50 percent gain in productivity due to the use of micro-irrigation.

Micro-irrigation also reduces problems due to weed growth, soil erosion and the cost of cultivation in labour-intensive operations. Reduced water consumption due to micro irrigation also helps to lower the use of electricity for lifting of water from irrigation wells. Realising its potential, the government programmes too are promoting micro irrigation through their schemes. For instance, the Pradhan Mantri Krishi Sinchayee Yojana was enforced in 2014 with the objective of ‘more crop per drop’.

While a number of studies have looked at the hurdles and benefits experienced by farmers after using micro-irrigation, many of these have been conducted at the plot level while limited research has been conducted at the basin-wide and the irrigation system level.

A study ‘Can micro-irrigation technologies resolve India’s groundwater crisis? Reflections from dark-regions in Gujarat’ published in the journal International Journal of the Commons aims to examine the impact of micro-irrigation adoption on groundwater extraction at the irrigation system level in dark regions of Gujarat, known for over-exploitation of groundwater.

In these regions, farmers mostly depend on groundwater for irrigation and obtain water from a common tubewell/aquifer. All the dark-zone talukas fall under the six agroclimatic zones: north Gujarat (36 talukas), south Saurashtra (5 talukas), middle Gujarat (4 talukas), north Saurashtra (2 talukas), south Gujarat (3 talukas) and north-west arid (4 talukas).

Talukas in north Gujarat are notified as over-exploited and critical regions, in south Saurashtra, north Saurashtra, and north-west arid regions as semi-critical, and in the remaining zones like middle Gujarat and south Gujarat, under the safe category. 430 tubewell owning farmers who had adopted micro-irrigation in their fields in the dark zone area were interviewed for the study regarding their agricultural practices.

The study found that:

Farmers changed their agricultural management practices after adopting micro-irrigation.

  • 26 percent of the farmers increased gross irrigated area and 80 percent of tubewell owners increased frequency of irrigation in their fields.
  • An increase in cropping intensity was observed in the fields by 32 percent and around 37 percent of farmers diversified towards water intensive crops. Thus, adoption of micro-irrigation did not lead to reduction in use of groundwater in the area.

Metered electricity connections changed the picture

Groundwater extraction was aided by uncontrolled use of electricity to pump groundwater to irrigate the fields. Metered connections along with adoption of micro-irrigation led to significant reductions in groundwater use among the farmers.

The paper argues that mere promotion of technologies such as micro-irrigation may not lead to sustainable groundwater use unless farmers are encouraged to behave more responsibly under conditions of extreme water scarcity. 

The study shows that groundwater extraction is also related to uncontrolled use of electricity to pump water. The paper argues that while supporting the adoption of technologies such as micro-irrigation, the state should also effectively control the unregulated use of farm power by urgently metering all unmetered connections, to ensure sustainable use of groundwater.

A copy of the paper can be accessed here