Treating Saline & Sodic Soils

Oftentimes, saline and sodic soils are lumped together as one common problem, but they differ. And here’s how: Saline soil is high in salt, whereas sodic soil is high in sodium. In this instance, those two words are not interchangeable; however, these soil conditions are often mentioned together because they can occur in tandem. Both also require immediate and longer-term remediation efforts.

ABOUT SALINE SOILS

In saline soil, sodium joins with chlorine to form a salt. Saline soils often contain excess water attributed to the salt that leaches out from the sedimentary rock or saline irrigation water; it’s this precipitation that prompts the salts to rise to the surface, where it comes in contact with plants. The salt that’s present in saline soil reduces the availability of water to plants and, at high concentrations, can kill them.

ABOUT SODIC SOILS

In sodic soils, much of the chlorine has been washed away which leaves behind the sodium ions that bind to the clay particles in the soil. Once wet, the clays in sodic soil lose their ability to stick together, creating an unstable soil structure that can easily erode and, at the same time, become too dense for water or roots to penetrate. Sodic soils often have low oxygen levels but very high PH levels, which can become toxic to plants.

HOW TO KNOW IF YOUR LAWN HAS SALINE OR SODIC SOIL

Easy answer: Get a soil test done.

A soil test is the best way to determine if you have saline and/or sodic soil and will detail the level of the problem and help you pinpoint other possible issues to address too.

PRO TIP: Some soils can be both saline and sodic.

HOW TO TREAT SALINE & SODIC SOILS

Fortunately, nature has given us a simple solution: gypsum.

It’s used to increase iron and manganese loss in soil. Applying gypsum helps dislodge the sodium in sodic clay soils and salt in saline soils and helps move these elements below the root zone away from your grass. Gypsum works by essentially displacing (in saline soil) the salt or replacing (in sodic soil) the sodium in the soil with calcium.

What to do when you grass is growing some, but it’s patchy and not healthy:

  • Apply gypsum over the top the lawn as recommended up to 2-6 times per year.
  • Water your lawn deeply to soak gypsum into the soil and allow it to work.
  • In the fall, add a ¼ inch layer of peat moss or high-quality top soil, then rake in evenly so as not to smother existing grass.

PRO TIP: Growing Kentucky Bluegrass? Consider overseeding with a more saline/sodic tolerable species such as tall fescue or perennial ryegrass (if you live in colder climates) or Bermuda grass (if you live in a warm climate). These types of grass can perform much better in saline and sodic soil conditions.

What to do when your lawn is hardly growing and complete remediation is needed:

  • Till in the recommended levels of gypsum per the advice of your local, professional lawn care provider, then add top soil or peat moss (i.e. organic matter) into the top 6 inches of your lawn.

PRO TIP: Tilling in organic matter will manually break up sodic soil and clay layers, which will increase water penetration and oxygen levels while also immediately reducing salt and/or sodium as well as reduce your lawn’s PH level to a more turf-friendly level.

  • Use 4-6 yards of organic matter per 1k sq ft of lawn.
  • Replant a more saline/sodic tolerable species of grass, such as tall fescue or ryegrass (if you live in a colder climate) or Bermuda grass (if you live in a warm climate). These types of grass can perform much better in saline and sodic soil conditions.

LONG-TERM TREATMENT FOR SALINE & SODIC SOILS

Let patience prevail. There is no overnight, quick-action fix for saline or sodic soils, or lawn that are both. Plan to retest your soil every year to ensure its getting the nutrients it needs to become healthy and strong.

Fixing saline and/or sodic soils may take years, and the key is persistent, consistent TLC. Add organic matter in the fall and gypsum as needed in the spring or summer. Humic is an excellent soil remediator to add, as is seaweed extract (which are ingredients you’ll find in Sunday’s lawn care products).

While fixing saline or sodic soils may appear to be an impossible, ever-diligent task, rest assured: once you address the problem, utilizing the above steps, and overseed or replant with grass types that are more tolerable of saline or sodic soils, you’re well on your way to having a beautiful, strong lawn that will be, when cared for with patience and soil nutrients, that will be more resilient in the long run.