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Drip Irrigation in the Tropics: Evidence from Southern India
Last registered on August 02, 2019


Trial Information
General Information
Drip Irrigation in the Tropics: Evidence from Southern India
Initial registration date
August 01, 2019
Last updated
August 02, 2019 3:36 PM EDT

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Primary Investigator
World Bank
Other Primary Investigator(s)
PI Affiliation
World Bank
PI Affiliation
Tel Aviv University
Additional Trial Information
On going
Start date
End date
Secondary IDs
Water scarcity is one of the fundamental challenges facing developing country agriculture. In South Asia, millions of privately-owned borewells have sprung up in the last two decades, to the point where groundwater has become the largest irrigation source in India, especially vital for dry season cultivation. While groundwater exploitation has contributed significantly to poverty reduction in rural India, unregulated drilling has also raised concerns about the sustainability of this crucial resource. Widespread adoption of drip irrigation has been proposed as a promising water-saving solution to the problem of groundwater over-exploitation. However, there is little, if any, rigorous evidence on the benefits, both in terms of agricultural production and potential water savings, of drip irrigation.

We implement a randomized control trial, in which a treatment group of borewell owners was encouraged to participate in a government subsidy program to adopt drip irrigation against a control group that kept the status quo. The study will track agricultural production, farm income, and water use in both groups before and after drip adoption.
External Link(s)
Registration Citation
Fishman, Ram, Xavier Gine and Hanan Jacoby. 2019. "Drip Irrigation in the Tropics: Evidence from Southern India." AEA RCT Registry. August 02.
Former Citation
Fishman, Ram et al. 2019. "Drip Irrigation in the Tropics: Evidence from Southern India." AEA RCT Registry. August 02.
Sponsors & Partners

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Experimental Details
Subsidies on drip irrigation are distributed through a partnership of India’s central and state governments. The Centrally Sponsored Scheme, released in 2005-06, provides 40% of drip costs, contingent on an additional 10% or more being offered by state governments. There is considerable variation in both the level of subsidy and the delivery of drip subsidies across states. Andhra Pradesh, the state in which this IE will be carried out, has recently increased is subsidy share to 50%, making for a total subsidy of 90%. The overall amount a farmer can receive is capped at levels that depend on land holdings. For the smallest total land holding category (< 10 acres), the cap is 100,000 Rs. per farmer, which allows for a 2 acre drip system, depending on the crop in question and other technical parameters. Farmers who have availed themselves of the subsidy in the past are ineligible to receive additional subsidies for a period of 10 years.

Government certified commercial suppliers can sell drip equipment to farmers at regulated prices and be eligible for the subsidy. In particular, the farmer applies for the subsidy at a local government agency, a process that is often facilitated by the supplier, and involves the submission of documents establishing land ownership and a legal electricity connection for the pump. Once the farmer pays his share (10%) and the application is approved, the drip supplier installs the equipment. Finally, once the government verifies the installation, the remaining 90% of the costs are transferred directly to the supplier.

The intervention was implemented as follows. We offered to pay the farmer’s share of the cost of the drip system (i.e., the 10%, limited to 10,000 Rs. per farmer) and to connect them with a drip company. Jain Irrigation Inc., one of the world’s largest suppliers of drip systems and the one with the largest market share in India, agreed to handle the subsidy application process and the installation of all drip systems and to provide close technical support to participating farmers.
Intervention Start Date
Intervention End Date
Primary Outcomes
Primary Outcomes (end points)
utcome Name Definition Measurement Level
Total profit Total revenue – cost (Rs.) Borewell-plot
Cultivated area Acres Borewell-plot
Crop choice High water intensity (Wet) vs. low water intensity (Irrigated dry) Borewell-plot
Water Sales revenue Rs. Borewell
Irrigated area Acres Borewell
Well Use Frequency and duration Borewell
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Outcome Name Definition Measurement Level
Profit per acre for crop under drip Net revenue/Acre Borewell-plot
Yield for crop under drip Tons / Acre Borewell-plot
Labor Use Quantity (man-hours per acre) Borewell-plot
Water Use Frequency and duration Borewell-plot
Fertilizer Use Quantity (kg per acre) Borewell-plot
Water Transactions Any water transferred to Adjacency
neighboring parcels?
Amount (area under), price,
and nature of contract
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
Sampling must account for the localized nature of groundwater markets; the vast majority of these transactions occur between adjacent plots. Thus, the highest level unit of analysis for the study is the adjacency of plots around a reference borewell. Our sampling frame will be drawn from the 2012 Groundwater Markets Survey (henceforth GMS; see Giné and Jacoby, 2019). As in that survey, the owner of the reference borewell will be surveyed with regards to his plot (reference plot), but he will also report on water transfers to any of the adjacent plots. Based on GMS data, inclusive of the reference borewell, there are typically 2-3 wells within an adjacency (mean = 2.5).

The experiment will consist of a treatment arms and a control group. The treatment will entail subsidized drip adoption on the reference borewell plot. As noted, this involves a total investment of around 100,000 Rs. (10% of which will be subsidized through the experimental intervention) that covers a drip system for around 2 acres.
Experimental Design Details
Not available
Randomization Method
Randomization done in office by a computer
Randomization Unit
Adjacency of all plots around a reference borewell belonging to a farmer
Was the treatment clustered?
Experiment Characteristics
Sample size: planned number of clusters
Sample size: planned number of observations
861 adjacencies
Sample size (or number of clusters) by treatment arms
471 control adjacencies and 390 treated adjacencies
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB Name
IRB Approval Date
IRB Approval Number
Analysis Plan
Analysis Plan Documents