Water scarcity is reaching a new level in India and is expected to get further aggravated in the near future. Farmers are facing a lot of difficulties in cultivating crops given reduced water availability in different regions. In this regard, deploying efficient techniques of irrigation enable the application of the right amount of water to the crop at the right time, besides ensuring uniform distribution in the field.
India Infrastructure takes a look at some of the irrigation techniques used in the country…
Current irrigation techniques
- Well and tube well irrigation: This is a simple, cost-effective and reliable method and it makes the soil fertile due to the chemicals mixed in the groundwater. At places where groundwater is available, a tube well can be installed near the agricultural area. A deep tube well, operated by electricity, can irrigate a much larger area (about 400 hectares) than a surface well (half a hectare).
- Canal irrigation: Canals can be an effective source of irrigation in areas with low-level relief, deep fertile soils, perennial sources of water and extensive command areas. Therefore, canal irrigation is mainly concentrated in the northern plains of India, especially the areas comprising Uttar Pradesh, Haryana and Punjab.
- Tank irrigation: In this method, a tank is developed by constructing a small bund out of earth or stones, built across a stream. This is an important source of irrigation in the Karnataka plateau, Madhya Pradesh, Maharashtra, Odisha, Kerala, the Bundelkhand area of Uttar Pradesh, Rajasthan and Gujarat.
- Micro-irrigation: The area covered under micro-irrigation has increased over the years. This method, through its water-saving approach, has paved the way for higher water use efficiency of around 75-95 per cent. In addition, fertigation has been made possible with micro-irrigation, resulting in balanced nutrient application, thus reducing fertiliser requirements.
- Check basin irrigation: In the check basin method, the whole field is divided into basins, which are connected through a small drain-type flow-way laid along the slope. This method is useful for levelled fields and soils with lesser infiltration, as it irrigates a larger area while reducing soil erosion.
- Basin irrigation: The basin method of irrigation is essentially the check basin method applied to orchards. In flat lands, the basins are square, while on sloping lands the basins are formed by constructing ridges along adjacent contours, with short cross ridges at either end.
- Furrow and strip irrigation: In this method, strips/furrows are separated by low embankments. The water is diverted from the field channel into the strips. This method is economical, but not suitable for all types of crops.
- Surge irrigation: Surge irrigation is a variant of furrow irrigation where the water supply is pulsed on and off in planned time periods. The wetting and drying cycles reduce infiltration rates, resulting in faster advance rates and higher uniformities than with continuous flow.
- Border irrigation: Border irrigation is a controlled surface flooding method of water application wherein the field is divided into long parallel strips called borders, which are separated by low ridges. This method is most suitable for close growing grain crops, such as wheat, barley and fodder crops.
- Free-flooding irrigation: In this method, the land is divided into plots and water is spread over the field from the watercourse. The irrigation operation begins at a higher area and proceeds towards the lower levels.
Key technological advancements
Micro-irrigation technologies are increasingly being seen as a means of addressing water scarcity problems and ensuring efficiency. The Canal Network Flow Monitoring System, deployed at Walamtari, is a comprehensive system meant to monitor canal systems and on-farm parameters using sensors, remote terminal units and information and communication technology. Besides, several agricultural tech start-ups have devised systems such as automated drip and sprinkler irrigation, supported by soil moisture sensors and microcontrollers, the GSM Bluetooth-based Remote Controlled Embedded System for irrigation, and computerised irrigation programs incorporating global positioning system information.
Automated irrigation systems have resulted in the employment of internet of things technologies whereby devices communicate among themselves to determine the soil condition before watering the field. Moreover, advancements in sprinkler systems have improved water-application patterns through the use of multiple streams, sizes and angles. Meanwhile, decision management tools such as computer-based crop growth simulation models are being used to predict potential crop outcomes based on historic climate data, local weather patterns and management practices.
The way forward
With half the cultivable land in the country still being rain-fed, there is huge potential for promoting micro-irrigation and related technology applications. Modern-day technologies need to be integrated with traditional methods to align the technology to local requirements. Farmers should be acquainted with the type of soil moisture, quality of irrigation water, and frequency of irrigation for the proper implementation of irrigation systems. While many techniques and strategies are already available that can contribute to this goal, there is a need to scale them up from the local to the landscape or regional level.