The Agronomists, Ep 87: Garth Donald and Caleb Niemeyer on variable rate applications for seed and fertilizer


Technology is continuously changing, and along with that is how we implement said technology on farms.

For this edition of The Agronomists, host Lyndsey Smith is joined by Garth Donald of Decisive Farming, and Caleb Niemeyer of Woodrill Ltd, to discuss variable rate applications for seed and fertilizer.

This episode of The Agronomists is brought to you by ADAMA Canada, Decisive Farming by Telus Agriculture, and the Pulse School.

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

Don’t forget to apply for your CCA/CEU credits!


  • Donald’s focus is on variable rate
  • Niemeyer’s focus is on soil mapping
  • What can we do, but what do we do most of with variable rate technology?
  • The overall promise for variable rate is still sustainability. Buzz word, or not, it’s where it all came about. Using your fertilizer and placing it where it can be utilized by the plants efficiently
  • Different parts of a field are going to respond to fertilizer differently
  • The soils are different, so we should be treating it different
  • How do we get the magic going with variable rate adoption? Where is the magic not happening most often?
  • Lots of times it goes back to family. How has it been done in the past?
  • Is there a certain size of field that requires VR? Niemeyer says there isn’t too much of a size barrier from the custom perspective. It’s not too consequential. It’s more of what operation has what equipment
  • Donald says it depends on economies of scale
  • Some crops aren’t so fit for VR, while others are

CLIP 1: Corn School: Counting tassels to evaluate variable rate seeding

  • Optimal rates across the field
  • On well-drained soils, they are going to be soils where they turn off the fungicide application. Visa versa on fields that see higher fungicide applications
  • Looking at multi-years is key when developing composite maps. Then the grower can have trust in the map
  • It all starts from the ground up. If you don’t have that starting point, you’re shooting from the seat of your pants, with no certainty
  • Digital soil maps are really cool
  • We just LOVE soil cores. Soil nerds, unite
  • Niemeyer composites multiple weeks of NDVI over multiple years
  • Just because an area doesn’t have high variability, doesn’t mean there isn’t variability. It’s how you address that variability
  • We have to know what is going on underneath to know why an area is poor
  • 20-30 cores in a bucket…now you’ve got a composite sample
  • Benchmark your zones
  • Not a surprise, but we didn’t get to clip 2. It’s a fascinating story…check it out!

CLIP 2: Soil School: Profitability mapping for conservation

  • Yield maps are great but they aren’t profitability maps
  • How do you make that leap?
  • It’s not just a matter of making a map, and throwing it across the table. It’s analyzing the map, and looking at what happened.
  • It’s not field profitability, it’s acre profitability
  • The profitability equation…let’s talk tillage.
  • Grain price – inputs = profitability
  • We can look at the visuals, but we have to look at the stats behind the maps, too
  • Soils are not formed in squares or rectangles, so we shouldn’t necessarily be grid sampling
  • There are many companies for imagery
  • Google earth is a nice tool to use for people that are looking for quick and simple.

Wake up with RealAgriculture

Subscribe to our daily newsletters to keep you up-to-date with our latest coverage every morning.

Wake up with RealAgriculture

Other Episodes

The Agronomists (view all)Season 3 (2022) Episode 9

Please register to read and comment.

Privacy Preference Center


Necessary cookies help make a website usable by enabling basic functions like page navigation and access to secure areas of the website. The website cannot function properly without these cookies.

gdpr, __cfduid, PHPSESSID, wordpress_test_cookie, woocommerce_items_in_cart, woocommerce_cart_hash, wp_woocommerce_session, wordpress_logged_in, wordpress_sec, wp-settings, wp-settings-time, __cf_mob_redir, wordpress_cache, realag


Measuring interactions with the ads on the domain.



These are used to track user interaction and detect potential problems. These help us improve our services by providing analytical data on how users use this site.



Preference cookies enable the website to remember information that changes the way the website behaves or looks, like your preferred language or the region that you are in.

chartdefaults, comment_author, comment_author_email, comment_author_url
JSESSIONID, _os_session,anonymous_votes,csrf-param,csrf-token,user,user-id,user-platform,intercom-session,intercom-lou,intercom-session
personalization_id, tfw_exp


Register for a RealAgriculture account to manage your Shortcut menu instead of the default.