Conserving energy in irrigation

Introduction

Irrigating effectively helps to conserve water and can also reduce energy costs. This fact sheet discusses practices to conserve energy through irrigation.

Effective irrigation

Effective irrigation means applying the right amount of water only when the plant needs it (Figure 1). This avoids unnecessary water pumping, which uses energy and costs money.

Here are 4 ways to achieve effective irrigation:

• Know the general water requirements of the crop.
• Use an irrigation schedule to determine how much irrigation to apply and how often, based on crop, soil texture and climate.
• Modify the irrigation schedule, based on current weather (rain and temperature).
• Check the effectiveness of the irrigation schedule and methods by monitoring soil moisture.

Example of over irrigation

Over-applying 2.5 centimetres (1 inch) of water over 0.4 hectares (1 acre) costs about $15 in energy to operate an irrigation traveller with limited lift and a short distance to the field. Multiply that by the number of irrigated hectares and the costs begin to add up. On a 20-hectare (50-acre) farm, 5 centimetres (2 inches) of water are applied when the plants require only 3.8 centimetres (1.5 inches). Irrigation is applied 6 times, when 4 times would have been enough. This means approximately 15 centimetres (6 inches) of water were applied unnecessarily. The over-application of those 15 centimetres (6 inches) over 20 hectares (50 acres) costs $4,500.

Other energy conservation tips

• Irrigate on calm days instead of windy days, as the uniformity of overhead water application (sprinklers/guns) is very poor under windy conditions.
• When possible, irrigate on cooler, cloudy days when evaporation will be lower.
• Irrigate at night (if possible) when less moisture will be lost through evaporation.
• Apply only the amount of water required for crop growth (excess watering wastes energy and money) (Figure 1).
• Check system regularly for leaks, and repair immediately.

Author credits

This fact sheet was written by Rebecca Shortt, P. Eng., water quantity engineer, Ministry of Agriculture, Food and Agribusiness (OMAFA), and was reviewed by Jake DeBruyn, P. Eng., new technology integration engineer, OMAFA.

It was developed with sponsorship from Hydro One and in partnership with the Ontario Power Authority, the Ontario Federation of Agriculture, the Ministry of Energy and the OMAFA.