The Agronomists, Ep 76: Len Hingley and Catherine Kerkhoff on irrigation management


Guest host Kara Oosterhuis is tackling irrigation management in this episode of The Agronomists, with guests Catherine Kerkhoff of Hytech Production, and Len Hingley of Alberta Agriculture, Forestry & Rural Economic Development.

This episode of The Agronomists is brought to you by ADAMA Canada, the Mind Your Farm Business podcast, and our July 19th webinar on infrastructure investment.

Catch a new episode of The Agronomists every Monday at 8 pm E!


  • The talented Kara Oosterhuis takes the host seat tonight. She’s from an irrigation-friendly farm. But today the Big White Combine massacred most of the farm
  • But, as they say, the show must go on
  • There are three different methods of irrigation
  • First is plant-based, or indirect measurements of soil moisture. These could be sap flow sensor or an infrared thermometer
  • Can use a crop water stress index as well
  • Then, there’s a microwave sensor, gives you an idea of the volumetric soil water content based on emissivity of the soil. The higher a emissivity levels, the higher the stress of the crop
  • Next is drilling methods and the soil base method
  • The most crude, of course, is your shovel! Cheap, but accessible
  • On to a Dutch auger (hold the chocolate sprinkles) or a push probe, which uses tension in the soil to measure soil moisture
  • There are also wireless soil moisture sensors
  • Farmers are looking at more moisture probes out of curiosity
  • Many using direct seeding are using the shovel method; they know their soil
  • Shovels are OK, but not precise
  • There’s value in evaluating dryness at depth and root growth, too
  • It’s important that we know a where the roots are and be where the moisture sitting because maybe we have that bottom soil zone maybe we’ve got more potential than we realize even right maybe it’s not as dry as we thought in the first place.
  • A soil core will tell you if you have dryness at depth, that’s where the roots pull from
  • Soil texture is a huge factor in decision making
  • Texture is critical. Understanding how water moves through the soil and is held in the soil is key
  • General questions, such as how heavy is the soil? How light is a soil? Do you have spots that run off more? Do you have spots that really can take in the three inches if you need it? How does the soil texture change further down
  • What’s the best way to start irrigation management on new-to-you ground?
  • Find the best and worst parts of the field. Check the lowest spots, the highest spots, and then an average spot
  • As an example, on a 65-acre field you do at least three or four soil tests
  • Let’s talk ribbon tests! You kind of just get a feel for it over time
  • Some people are so good at estimating needed moisture by the ribbon test
  • Don’t be discouraged, focus on those 25 per cent increments, and if you can look at it like that, then you don’t have as much stress on your on your farm
  • If the soil balls up and leaves a stain on your hand, and you can actually see the stain itself, you’re at around 75 per cent to 70 per cent, that’s where you want it over that anything. And if it stains, and if you actually can push push some liquid out of your hand between your fingers, then you know you’re at around 95 to 100 per cent
  • Clip 1: Corn School on subsurface drip technology
  • Trials of drip irrigation management of alfalfa seed in Alberta. Why alfalfa seed? Because bees don’t like getting rained on
  • With a sandy soil, water drops down immediately. With a coarse or fine textured soil, it moves out laterally before moving down
  • That’s important for spacing and tape spacing
  • What’s ET? (not E.T.). Evaporation and transpiration!
  • Know your water loss routes, y’all
  • If you’re confused and not sure what to put down, look at your peak use times for alfalfa, corn,  grass,  and work from there
  • Remember that effective root zone; it gets deeper as the plant grows/matures
  • Fertilizer plus irrigation equals fertigation
  • Subsurface drip likely has biggest potential gains because you’re injecting fertilizer right to the root zone
  • Disease management under irrigation just hits different
  • Clip 2: Wheat School with Kelly Turkington
  • Every crop is different, some times the best option is to let it dry out to keep disease levels in check. And that’s the hardest thing!
  • For fusarium head blight in wheat, it’s so key to shut that water off at flowering
  • Questions: what about sprinkler choice on the pivot?
  • What about getting in to the canopy vs. over top? Corn is a challenge, so is thick canola
  • Wind is a factor in evaporation and transpiration = water loss
  • Did you know? You can’t just turn on water whenever you like, and there’s not an endless supply of water, either
  • Irrigating at night is more efficient at night, in theory, but then you’d have to pause during the day
  • Precision irrigation technology is coming online too but not perfect yet
  • Customer support is key


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