Water Use Efficiency

Wednesday, July 8, 2020

As members of the agriculture industry, we feel the effects of the weather in everything we do and even more so in a year full of challenges, like the one that we’ve had so far. With so little rain in June for most parts of the province (Table 1) and irrigation ponds running lower than usual for this time of year, it is important to take some steps to ensure efficient water usage.

Table 1. Precipitation in Nova Scotia in June 2020 compared to the historical average from June 1981-2010.

Weather Station Location

Total Precipitation June 2020 (mm)

Average Precipitation for June 1981-2010 (mm)

Percentage of Historical Average Rainfall for June (%)

Kentville

49.1

81.6

60.17

Greenwood

25.2

81.0

31.11

Debert

33.9

95.9

35.35

Yarmouth

16.3

94.8

17.19

Sydney

84.0

96.9

86.69

Nappan

20.8

82.6

25.18

 

Make sure irrigation equipment is in good working order.

A cracked irrigation pipe or a leak at a loose fitting may seem like a small issue when there are so many other things that need to be done in the run of a day – especially when labour is already in tight supply. Over the course of a week, you may be losing significant amounts of water which could make the difference for one of your crops later in the season. Check all components and connections in the irrigation system regularly and carry out preventative maintenance when possible.

                               

Although trickle irrigation is more efficient than overhead types, it is still possible to have breaks or poor connections. These lines should be checked and maintained as well.

Irrigate in the morning or evening to avoid excess evaporation.

Where there is limited irrigation equipment or there are many crops that need to be irrigated, it may not be possible to avoid irrigating when the water is most likely to evaporate, when the sun is blazing and the wind is high. Irrigating when there is less chance of water loss to evaporation may be a more efficient method but may also exacerbate disease infections. If there is disease present already, or the crop is particularly susceptible to fungal infections, irrigating at night may provide the cool and damp temperatures needed for disease to flourish. Weigh the benefits of each option and choose what makes the most sense for your crop.

                                           

Greenhouses can experience water stress as well.

In the field, drought stress usually develops over time, allowing the plants to get used to the environmental changes little by little, but in the greenhouse where the environment is more controlled, an abrupt reduction in water supply may cause severe physiological stress in the plants. Be sure to monitor water supply and start rationing if necessary, to ease the shock that would be caused by sudden drought stress.

                                 

Be prepared to make tough choices.

In long periods of drought there may come a point where water supply is so limited that there isn’t enough capacity to water every crop sufficiently. Some factors to consider in deciding which crops take priority for water include critical growth stage, effect on marketability, value of the crop, etc.

For more information, check out OMAFRA’s factsheet “How to Prepare for Irrigation During Water Shortages”.



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