Wheat School: Soil pH, salinity, and choosing the right soil test


When you send soil samples for testing, what do you ask for?

If you’re following Ross McKenzie’s advice, there’s likely some real value in testing more than just nitrogen, phosphorus, potassium, and sulphur (N, P, K, and S).

The former Alberta Agriculture soil scientist says it’s not too late to test soil this year, as frozen ground may require more effort to sample, but the samples should be stable, offering a decent look at what will be there for the crop in the spring.

McKenzie says there is great value in knowing what N, P, K, and S is available, but several other soil components are also valuable to measure, as they can have a significant impact on nutrient availability or identify why you’re short yield in certain areas of the field.

(Story continues below the video)

If you’re soil testing, consider testing for:

  • Soil pH
    • Soil pH can change dramatically across a field and with topography. What’s more, soils can acidify over time, especially under no-till systems where the soil layers aren’t physically mixed. Acidic soils can have a negative effect on N-fixing bacteria with pulse crops in rotation.
  • Salinity
    • Measured as EC (electrical conductivity). An elevated EC value could mean you’re losing  30 to 40 per cent of yield potential, but you still don’t see white on the field surface. This is “hidden salinity” and it can have a real impact on the crop.
  • Soil organic matter (organic carbon)
    • This test is not super precise, but will give you an idea of a soil’s OM and if that number is climbing or falling.

McKenzie says to double check that the lab doing the soil analysis is using the correct phosphorus extraction method when testing. Depending on the province you’re in, there are some major differences in the findings. For example, Manitoba soil samples typically use the Olson method, but that method won’t give as accurate results for Alberta samples. The Olson method works best on higher pH soils, like in Manitoba.

Check out more Wheat School episodes here

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

Wheat School (view all)Season 10 (2019) Episode 4

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.