Soil compaction is a relatively common problem, which occurs when the soil becomes pressed down in response to pressure. This pressure can arise from vehicular traffic, foot traffic or even pets who pace across the same area over a period of time. Irrigation water which repeatedly slams the same area over and over, such as often occurs when sprinklers are used, can also pack down the soil in your yard.
However, thanks to the heavy machinery used in the process, construction projects are some of the most common causes of soil compaction. In fact, most areas require large-scale construction projects to take special precautions designed to prevent compaction.
Why Is Soil Compaction a Problem?
Compaction reduces the rate at which water can infiltrate the soil, and it reduces the amount of oxygen present too. It also makes it more difficult for a tree’s roots to penetrate the soil and develop the kind of rich, dense network you’d want, which can reduce the tree’s vigor and subject it to wind-throw.
Fortunately, there are a few different ways to deal with soil compaction. Some are easier (and more affordable) than others, but each case is unique and some of these strategies may not be possible in your situation.
A few of the most effective ways of loosening up your soil include:
Physically creating a series of holes in the soil with a specialized tool (called an aerator) can help eliminate soil compaction and prepare it to support plants and trees. This time of treatment usually involves drilling holes about 7 to 8 centimetres deep, which means that you’ll be able to address the upper layers of the soil, but not those deeper than the holes penetrate.
If your soil is extremely compacted, or you need results in a matter of hours, the best way to address the problem is by re-grading the entire area with earth-moving equipment. To do so, the compacted soil will need to be dug up, stirred or mixed and then placed back in the original location without applying too much pressure.
Adding 5 to 10 centimetres of organic mulch on top of your soil is one of the easiest ways to help address soil compaction. The organic material will break down slowly over time, work its way into the soil and reduce the bulk density of the soil. However, this takes a considerable amount of time – measured in years. Accordingly, it is certainly not a quick fix.
Vertical mulching involves digging or drilling vertical holes in an area and then filling these holes with organic compost or mulch. This works via the same general principle that surface mulching does, except that it can improve the soil’s condition more quickly, as the material is placed deep in the ground.
Usually conducted around trees in compacted soil, radial trenching requires you to dig several trenches extending from near the trunk of the tree in question. These trenches can then be re-filled with loosened topsoil, compost, mulch or a combination of these materials. Care must be taken when radially trenching, so you do not harm any tree roots unnecessarily.
Earthworms are a fantastic way to address soil compaction, as their tunnels create the same types of holes produced when the soil is aerated or vertically mulched. Earthworms won’t be swayed by areas of compacted soil; they’ll simply eat their way through the hard-packed regions.
High-pressure air can be used to blast apart compacted soils, thereby letting the soil re-settle in a non-compacted fashion. Although a moderately time-consuming solution, air excavation is the preferred method of many tree-care professionals, as it is relatively gentle on nearby tree roots.
A Supplemental Strategy
In some cases, it may be helpful to inoculate your land with mycorrhizal fungi when battling soil compaction. Mycorrhizae are symbiotic fungi that live on the roots of plants. They help the plant secure additional water and nutrients, while the plant provides them with carbohydrates, which the fungi “eat.”
Because soil compaction reduces the rate at which roots can spread and obtain resources, it can often help your plants and trees to cope with the soil while you try to fix the situation and after you’ve finished.
If you believe your soil is too compacted to allow proper water infiltration, air exchange and root development, give your friends at Trav’s Tree Service a call. One of our experienced arborists will visit your home, assess your soil condition and then recommend the best type of treatment. You’ll often be surprised home much better your trees and greenscapes will look after doing so.