The consensus among soil scientists is that alleviating urban soil com- paction is a very hard job. Indeed, Randrup (1998) notes that once a soil is compacted, it is extremely difficult to restore its original structure, particularly if the compac- tion extends several feet below the surface.
When the soil is weak at depth, compaction can result from vehicle traffic, and it is generally harder to reverse than compaction at the surface. Some soils may naturally return after tillage to a compacted state that will significantly impede root growth.
Artificial drainage can help increase the number of trafficable days on poorly drained soil. Keep axle loads below 10 tons. Subsoil compaction is caused by axle load and is basically permanent. To avoid subsoil compaction, keep axle loads below 10 tons per axle--preferably below 6 tons per axle.
Top-dressing planting beds with several inches of compost will improve lightly compacted soils. Earthworms and other soil fauna will gradually pull it down into the soil, loosening it and improving water-holding capacity. A 2- or 3-inch layer of shredded leaf mulch or wood chips will provide similar benefits.
Luckily, this can be done fairly easily just by covering the soil with organic material such as fall leaves or woodchips. And if you've got a bunch of grass or other plants you don't want anymore, just add a layer of cardboard first before you add the organic material.
Reduce soil compaction in tillage land
To avoid surface compaction use vegetation or crop residues to provide cover. Add organic matter to help strengthen the soil. Treat deeper compaction with a subsoiler to create vertical cracks in the soil profile.
Combining heavy axle loads and wet soil conditions increase compaction's depth in the soil profile. For example, a load of 10 tons per axle or more on wet soils can extend compaction to depths of two feet or more.
1 Aeration creates holes down into the soil to alleviate compaction so air, water and nutrients can reach grass roots. Deprived of their basic needs by compacted soil, lawn grasses struggle in stressful situations, such as heat and low rainfall, and lose their healthy, rich color.
Will My Soil Be Compacted After a Heavy Rain? The force of raindrops mechanically compacts surface dirt, creating a soil crust that is up to ½-inch deep. This layer impedes drainage and makes it hard for seedlings to emerge from soil.
This will cost in the $2,000 to $3,000 range, for the soils compaction report. This can be more money if there is a large building pad.
The two most common methods for alleviating compaction are soil ripping (also called subsoiling or tilling) and addition of organic matter. These two are typically combined.
Alleviate compaction by adding organic matter to the surface, in the form of mulch. The mulch will break down and organic matter will, slowly but surely, fall into the soil below.
Farming system strategies that minimize tillage, maximize living cover (e.g., the QSMAS system), and utilize additional organic inputs (e.g., animal manures) have a strong track record of restoring the productivity of soils degraded by water erosion.
As old soil might be deficient in plant nutrients, you need to replenish it. Here are some ways you can add nutrients and organic matter to soil: Add a handful of a slow release fertilizer like manure. Mix in one part compost for every three or four parts of the old potting mix.
Restoring good vegetation to degraded soil helps to maintain its structure, as the roots become strongly anchored, generating a cycle of organic matter that can help to restore fertility.
Aerate the Soil
This is the most common and effective method for fixing compacted soil. Aeration involves creating holes in the soil to allow air, water, and nutrients to penetrate deeper layers. There are two main types of aeration: core and spike aeration.
Tamping rammers and jumping jacks are useful for compacting soils in 2 to 3 lifts thick, at near-optimum moisture content, if trying to achieve 90% compaction. Choosing the proper equipment is just as important as the compaction and number of passes itself.
Core aeration is considered the best and most effective way of loosening your compact soil. Other methods of aeration, such as spiking, don't remove any soil from your lawn, so they can actually make your compaction issue worse. During core aeration, tiny plugs or cores are pulled up throughout your yard.
Digging forks or garden forks are the best digging tools for breaking up rocky or hard soil. With their long, sharp-edged tines, these gardening tools are also good for aerating soil and digging up potatoes or other root vegetables. Ground rakes or garden rakes have several short, metal tines.
After a rain, water does not move as easily through the soil and a mini-pond is created when the soil finally dries, resembling an alligator's skin. This linear pattern of cracked soil does not let air or water in. Working the soil when it is too wet is another frequent form of compaction.