Drip Irrigation Method: Transforming Indian Agriculture Drop by Drop

Table of Contents

• Introduction
• What is Drip Irrigation?
• Status of Drip Irrigation in India
• Crops Suitable for Drip Irrigation
• Types of Drip Irrigation
• Drip Irrigation Model: Components of Drip System
• Drip Irrigation Method: How Does Drip Irrigation Work?
• Benefits of Drip Irrigation in India
• Limitations of Drip Irrigation
• Government Support for Drip Irrigation

Introduction

Agricultural operations like irrigation rely heavily on the availability of water. As per a 2022 report, the Annual Ground Water Extraction meant for all types of use was 239.16 billion cubic meters (BCM). Of this, around 87% (208.49 BCM) was used for agricultural activities. Due to prevailing water scarcity in India, the need of the hour is to manage water use efficiently in agriculture.

This is where the drip irrigation method comes in. It saves water and nutrients by precisely delivering them to the root zone of crops. Read on to understand what is drip system, its components, uses and benefits.

What is Drip Irrigation?

Drip or trickle irrigation is an efficient irrigation method that ensures less water consumption compared to surface irrigation. A network of pipes, valves and emitters delivers water directly to the crops' roots. This irrigation technique is highly suitable for most crops, including oil seeds, cash crops, vegetables and fruits. Also, fertigation is used to apply fertilisers using drip irrigation to carry and distribute water and nutrients.

The root zone receives almost all water in the drip irrigation system. There is nearly no wetness in surface area; thus, this method needs 25% less water than surface irrigation. Also, drip irrigation is suitable for saline soil conditions.

Status of Drip Irrigation in India

In the 1970s, drip irrigation technologies from developed nations like the US and Israel were introduced in India. 4374.53 thousand hectares area was noted to be under drip irrigation in 2019. Maharashtra, Andhra Pradesh, Sikkim and Karnataka are the leading users of drip irrigation.

In 2021-22, the area covered under drip irrigation in Pradhan Mantri Krishi Sinchayee Yojana (PMKSY) was 3.58 lakh hectares. Also, the largest drip irrigation programme in Asia is the Ramthal (Marol) Micro Irrigation Project located in Karnataka.

Types of Drip Irrigation

The following are the primary types of drip irrigation systems:

• Surface Drip Irrigation: Emitters and laterals are placed on the surface using this system. It provides water near the root zones of crops and maintains desired soil moisture. There is less soil wetted by surface drip irrigation than by surface irrigation methods.
• Subsurface Drip Irrigation: The installation of emitters and laterals is done below the soil's surface. The popularly used systems include cane wall, T-tape, Typhoon and Bi-wall systems. They are highly valuable for the irrigation of row crops.

Drip Irrigation Model: Components of Drip System

The components of the drip irrigation system have been categorised as:

• Pump: A water pump supplies water at a specific discharge capacity through the components of the system like fertiliser tank, filtering unit, mainline and laterals. Different water sources can be used for this system, including canal water, tank/reservoir, lake, river or wells.
• Filter Unit: This component filters out the suspended impurities in water before it reaches pipes or tubes. It does not allow pipes and emitters to clog.
• Mainline: The mainline transports water to the field and distribute it to submains uniformly. It supplies the total quantity of water needed for the system. Its pipes are generally made of high-density polyethylene (HDPE) or poly vinyl chloride (PVC).
• Sub-mains: Sub-mains can be installed above ground (HDPE) or below ground (HDPE/PVC). Laterals are fed by sub-mains. Generally, the sub mainline has a pressure rating of over 2.5 kg/cm² and 32-75 mm diameter of pipes.
• Laterals: They are used for uniform water distribution along their length with the help of emitters. Emitters have to be mounted or integrated within tubes called laterals. The material used for laterals includes LDPE and LLDPE
• Emitters: Drip nozzles discharge water from laterals to the soil. Water in the form of trickles is emitted at a slow rate for irrigating crops.

The other components of the drip irrigation model are valves, gauges, water meters, chemical tanks/injectors, etc.

Drip Irrigation Method: How Does Drip Irrigation Work?

Drip irrigation applies irrigation water with water-soluble fertilisers directly to the plant roots at a low discharge. The mainline supplies water to the sub-mains, which is then moved into the laterals. The emitters are fixed to the laterals for water distribution.

Emitters deliver water at a low operating pressure of 1 - 2 kg/cm². Based on different factors like the soil type, the emitter discharge is in the range of 0.5 to 12 litres per hour (lph). Due to the low discharge, partial wetting of the root zones is observed. 

Benefits of Drip Irrigation in India

The uses of drip irrigation result in various benefits for Indian farmers, such as contributing to sustainable agricultural practices. Other key benefits include:

• Water Conservation: Drip irrigation has the ability to save water. There is reduced evaporation and wastage as water is directly delivered to the root zone. Thus, it facilitates the efficient use of limited water resources.
• Higher Crop Yields: The drip irrigation method provides a consistent, controlled water supply and promotes optimal crop growth. Crop health improves due to precise water and nutrient delivery. Thus, there is a higher crop yield than traditional irrigation methods.
• Weed Control: As the irrigation water targets the root zone of plants, the surface is left relatively dry. Thus, the growth of weeds does not take place and labour involved in manual weeding is reduced.
• Labour Saving: A well-designed drip system is mostly automated. You just need to start or stop this system. Thus, expenses related to manual labour are considerably reduced.
• Soil Compatibility: Irrigation is also challenging in India because of diverse soil conditions. It is difficult to irrigate very light soils because of deep water percolation. Also, there are low infiltration rates in heavy soils. Drip irrigation is successful in both soil types.
• Energy Saving: Drip irrigation uses less water because of high irrigation efficiency. Thus, the time required for supplying irrigation water is reduced. So, the consumption of electricity or any other fuel source required to irrigate fields is minimised.

Limitations of Drip Irrigation

The limitations of drip irrigation are as follows:

• As this method uses several components, the initial cost of setting up the system is high. Thus, it demands an initial heavy investment.
• This irrigation system needs extensive maintenance. For example, proper and regular check of filter and other components is required for smooth functioning of the system. Otherwise, issues like clogged emitters or pipes can emerge.
• It can interfere with other farm operations, such as moving machinery and implements. This is mainly because of the network of pipes laid on the ground.

Government Support for Drip Irrigation

The Government of India is making huge efforts to help farmers adopt micro-irrigation. There is a provision of financial assistance/subsidy under Per Drop More Crop (PDMC) for installing drip and sprinkler irrigation systems. This subsidy amounts to 55% and 45% of the indicative unit cost for Small & Marginal farmers and other farmers, respectively. PDMC is a key component of Pradhan Mantri Krishi Sinchayee Yojana.

Drip irrigation is improving water use in agriculture. Its benefits promise a bright future for sustainable agriculture in India. As more farmers use government support to adopt this practice, earning more with high-value crops is becoming easier.