When homes are built, trenches are often created throughout the landscape for various reasons. Utilities, sewer lines for houses in cities, lines to septic systems and associated leach fields, and irrigation systems all get buried underground in trenches. Unless there is an issue, these features are generally out of sight and out of mind, but they become obvious under certain stress conditions. Here is a breakdown of trenches in your yard, and how you can better conceal them from the lawn care experts at Nature’s Turf in Georgia.
Why Is There A Pattern In My Yard?
Nature doesn’t create straight lines, and while there are repetitions and patterns in nature, it isn’t very difficult to discern a naturally created pattern from one created by people. Inevitably, especially in stressful conditions, we receive calls wondering if the patterns becoming evident in someone’s landscape are attributed to the applied fertilization and weed control.
While discoloration can be caused by all sorts of things like malfunctioning irrigation systems, repetitive mowing patterns, or mower injury created by undulations in landscape or mowing too low, we do see many clients with discoloration attributed to trenches. Georgia red clay presents lots of challenges to our landscapes and plays a major role in the reason trenches become obvious in a landscape.
Clay is the smallest of the soil particles. It can be hard to believe that since we generally don’t see a single particle of clay, but rather clods. As individuals, they are very small, meaning that they pack together tightly. There are many terms to describe this condition depending on context, but the one that applies here is compaction.
We’ve all tried to dig holes in clay. When it’s hot and dry outside, sinking a spade into the ground far enough to get a good scoop of earth can be a challenge in itself. Conceptualizing that it is difficult for roots to grow in this media is easy. If it is hard for us to dig, it must be difficult for roots to push through as well. The challenge of compaction for turfgrass doesn’t stop there.
Porosity is a term associated with compaction, but one that isn’t discussed as often. In soil, between those particles and colloids, you have voids of varying size and shape. Small ones are referred to as micropores, while large ones are called macropores. Each one of these pores will either be filled with air or water, the ratio of which is important for soil and root health. The roots of plants, our lawns included, grow into these pores to absorb water and nutrition. Without venturing too deeply into how plants draw water and nutrition in, suffice to say it’s much more difficult for them to retrieve it from soils that are majority micropores (compact), than soils that have better porosity.
When dirt is removed from a trench, its structure is changed completely. After installing the piping, conduit, or cabling for which the trench was made, the dirt has to be placed back over the top of it. Good contractors will tamp or attempt to recompress the dirt as it goes back in the trench, but attaining the same level of compaction as the surrounding clay is impossible. That means that the compaction in a trench is far less than the compaction outside making it much easier to get water and nutrition into the soil where the trenches are, as well as much easier for the roots of our turfgrasses to get water and nutrition back out. Turf grown over these trenches will have healthier root systems, making them more hardy in stress conditions, but will also have better water and nutrient availability during prolonged periods of heat, drought, or other stresses.
Why Do Trenches Sink?
Trenches sinking with time is also directly related to compaction. As established above, even tamping the dirt while replacing it in a trench cannot achieve exceptional compaction. As time goes on, the soil particles in the trenches will realign themselves, shifting and moving together to become more and more compact. This is the result of percolation, gravity, and even traffic resulting in trenches settling beneath the level surface created when the trench was initially filled. Not only is this not uncommon. It’s completely expected.
What Do I Do About My Trenches?
The short answer: fill them in. As the dirt settles leaving obvious trenches, it is time to back-fill them. This is best done with a mixture of sand and dirt. Sand allows for easy leveling while dirt gives the sand some staying power. Furthermore, the sand allows for great porosity while dirt gives nutrients something to cling to.
If your trenches are exceptionally deep, doing this in thinner layers is advised. The goal is improvement. In an instance where too much sand or soil is put down at a single time, you can end up with accidental smothering. Thin layers allow turfgrasses to grow both through and across, continuously helping cover them up.
As far as normalizing the color in stress situations, that simply comes with time and effort. Annual aerations to improve the soil health in your yard are fundamental. As the stand of turfgrass ages, so does the dirt beneath it. Establishing a relatively homogenous layer of healthy, organic matter rich, microorganism populated dirt takes time. With patience, good cultural practices, and care, reducing how obvious trenches are from both a quantitative and qualitative perspective is possible.
Important Takeaways:
- Nature doesn’t create straight lines, and while there are repetitions and patterns in nature, it isn’t very difficult to discern a naturally created pattern from one created by people.
- While many things can create inconsistencies in coloration, trenches are often the culprit for man-made patterns in the landscape.
- Georgia red clay presents lots of challenges to our landscapes, and plays a major role in the reason trenches become obvious in a landscape.
- When dirt is removed from a trench, its structure is generally changed completely. Compaction in a trench is far less than the compaction outside making it much easier to get water and nutrition into the soil where the trenches are, as well as much easier for the roots of our turfgrasses to get water and nutrition back out.
- With time, the soil particles in the trenches will realign themselves, shifting and moving together to become more and more compact. This is what causes settling.
- Patience, good cultural practices, and care, will reduce how obvious trenches are from both a quantitative and qualitative perspective.
