Determining Soil Compressive Strength Using a Pocket Penetrometer

Farm soil has many hidden factors that can lead to devastating effects, so knowing exactly what your farm’s soil compression level is can help you understand how improve it. A more compact soil can easily reduce crop yields by 10%, it can also lead to water and soil quality degradation because of increased runoff and soil destruction which can further lead to the degradation of the crop. And there are two layers of soil compaction surface compaction and subsurface compaction, both can be tested through the use of a penetrometer.

penetrometer soil

For surface compaction the process of tilling the soil for the crop will decrease it’s compression. Subsurface however it becomes much harder because there is no way to dig it all up and decrease the compression by the same method. Which is why testing using a penetrometer soil compression before you even plant any crops is essential.

The measurement unit for a penetrometer is usually kg and one common conversion is 1 kg/cm2= 98.1 kPa which measures the force needed to penetrate the earth which can then be written down on and measured on a graph which will show you the general compression of your soil. And a pocket penetrometer soil gauge is fairly common throughout most online stores in Australia.

The penetrometer has three parts the gauge, the shaft and the cone at the bottom (unless it is a telescopic pocket model where all of the parts are portable). Cones are the only part that you will need to replace because it’s what drives the shaft into the soil to measure the compression level. But for the pocket models you’ll need to do some digging before using them. You will need a hole big enough where you can stick the penetrometer into the wall of the hole and test the compression through that method. However this method isn’t as accurate as a standard penetrometer.

Once you’ve gauged and calculated the compaction of the soil and it’s psi is too strong for you crops you will need a deep subsoiler which can till the ground deep enough to allow the roots to grow longer. An unrestricted root will be able to set itself better within the ground and it’s ability to feed will be unhindered in less compacted soils. And remember to not overwork the soil, giving it enough time to settle before planting or re-tilling it, keeping it dry will also help in this process.