What should you keep in mind when irrigating your potato crops?
Irrigation can make all the difference for potato crops, but it isn’t as simple as just turning on the taps. At the International Potato Technology Expo in Charlottetown, P.E.I. on March 30 Michele Konschuh from the University of Lethbridge spoke to potato growers in Prince Edward Island, where regulation changes are now allowing for irrigation expansion, about what she’s learned researching irrigation over the years.
Here are some things to keep in mind when making decisions about irrigation on your farm:
- If you don’t add enough water to utilize the nitrogen, you’ve wasted your fertilizer. If you don’t apply water, soil moisture will limit the yield response to fertilizer.
- Soil water holding capacity is determined by soil type and effective root zone. Potatoes have a shallow effective root zone — their roots can’t draw water from deep down.
- Potatoes use the water from the hill, not the furrow. If there’s water in the furrow, it may be leaching nitrogen from under the furrow and going straight down, it doesn’t travel laterally to reach the roots. If you’re watering to the point where furrows are full, water is being wasted.
- When buying a soil moisture sensor, you need to know how long it will last for. You also need to consider who has access to the data created by it and how you are able access that data.
- In Alberta, dammer dikers are used to make divots in the furrows, this stops soil erosion made by channels of water running through fields.
- In Alberta they’ve found a low-pressure spray irrigation system is the most efficient model for watering crops. Impact sprinklers make droplets above the crop with many never reaching the plants reducing the efficiency rate.
- The problem with variable rate irrigation is it still requires someone to tell it where to water. Research is being done to make this happen using technology, but the tech isn’t there yet. There’s enormous potential though.
- Even if irrigation water is coming from a reservoir the water temperature is still going to be cooler than the plant. Konschuh hasn’t observed problems with watering in the heat, however more water will be lost to evapotranspiration.
Header photo — A centre pivot irrigation boom watering a potato crop on Prince Edward Island. Photo: P.E.I. Potato Board