What’s in your soil?

What’s in your soil?
(Source: Lisa Fotios/Pexels)

EAST TEXAS - Perhaps nothing is more therapeutic than digging in wonderful, dark, rich soil. Your shovel cuts easily down thru the soft, crumbly soil and is wonderful.

And in a clay site, nothing may be more frustrating than trying to dig a hole in hard packed clay. You start getting in to tough work, chipping away at the ground to just get very little from each subsequent shovel.

Or if you’ve lived on a site with deep “sugar-sand”, you’ve experienced the frustration of digging a foot or two deep, only to have the sides slough in and fill up what you just dug out. What should have been a nice flat-bottomed hole is an inverted cone of sand.

Often, I’ll ask folks what kind of ground they have. Almost everyone responds that they have a good loamy soil.

Since we know the incredible benefits of adding organic matter, lets discuss the three mineral components that you have already in your soil.

There are three soil particles: sand, silt and clay.

Sand is obviously the largest of the trio. When you rub sand between your fingers, you can feel it. It is granular and valuable to a well-drained site. Think of your time on any sandy beach. Water doesn’t puddle up on it. When you build a sandcastle, you must be careful that you give it enough structure as it will dry out and topple over.

Silt is the middle-sized soil particle. If you have been barefooted at a creek and seen the silty soil squish up between your toes, you are very likely looking at silt. Silt is small enough to be carried by moving water but large enough in size to settle out when the water is still. As a result, many river bottoms that occasionally flood have good, silty soil. That old pond at your grandparents isn’t nearly as deep as it once was because it has silted in.

Clay is the last and the smallest soil particle. While I fuss about too much clay, it does a good job of giving structure to the soil and will hold nutrients on its surface for plants to utilize. Clay will stay suspended in water, sometimes indefinitely. You know that old muddy water pond that…. has always been muddy? That is from clay suspended in the water that won’t settle out.

But, one asks, “What about loam? You forgot about the best kind of soil, loam!”

Loam is in fact the ideal combination of those three soil particles. According to soil science, the perfect loam soil is about 40% sand, 40% silt, and 20% clay. For those wishing to get deep into the subject, do an internet search for “soil triangle” and you can study the combinations of sand, silt, and clay to see how soils are classified.

For a simple home garden experiment, fill up a clear glass jar about half with your garden’s soil, then add water until it is nearly full. Shake vigorously and then let it set for hours, even overnight. You’ll see the proportions of sand, silt and clay as they settle out.

Sand will fall to the bottom almost immediately. Then there will be a layer of silt that will take much longer to settle. If left long enough, the clay will begin to settle out as well. What you’ll have at the end are the easily distinguishable three layers of minerals from your soil.

Its true that many folks in Angelina County do have a good loam topsoil. The real concern is the depth of the topsoil. There are places where it is several feet thick and we have sites where it may be only an inch or two deep.

I’ll continue this topic and have a seminar on Building Your Soil on Monday evening, Jan 20 at the Angelina County Extension office starting at 6:30 pm. There is no fee for the program.

Cary Sims is the County Extension Agent for agriculture and natural resources for Angelina County. His email address is cw-sims@tamu.edu,

The members of Texas A&M AgriLife will provide equal opportunities in programs and activities, education, and employment to all persons regardless of race, color, sex, religion, national origin, age, disability, genetic information, veteran status, sexual orientation or gender identity and will strive to achieve full and equal employment opportunity throughout Texas A&M AgriLife.