Why Should We Use A Soil Penetrometer to Measure Soil Compaction?

soil-compactionHave you ever come across a situation where you have provided proper nutrition and sufficient irrigation to your crop, yet the yields still don’t meet expectation? Well, it’s time to reconsider all the factors that are important for healthy crop yield. Most of the farmers assume they have taken care of all the factors required for good production by taking care of plant nutritional needs such as application of high yielding seeds, proper irrigation and plant protection needs such as pesticides. You might have provided all the nutrition, but is the plant getting this nutrition? If you are feeling confused, this article is just for you.

If the soil is too compact, chances are your crop might not receive nutrition or irrigation you are supplying them. Soil with high bulk density also means low soil porosity. This is referred as density and reflects the soil’s ability to provide functional support such as movement of water and solute and soil aeration. Bulk density beyond certain threshold limit indicates impaired function. High bulk density soil can restrict root growth and movement of air and water through the soil. This will result in shallow plant rooting and poor plant growth leading to poor crop yield and reduction in available vegetative cover that protects soil from erosion.

If the water is not able to infiltrate into the soil, the soil compaction can accelerate the rate of runoff and erosion from sloping land or water logged soils in flatter areas. Under certain circumstances soil compaction is beneficial such as arid condition where soil compaction restricts movement through soil profile. However under humid conditions compaction decreases yield.

There are two main types of soil compaction namely surface and sub-surface. Surface compaction can be elevated using normal tillage operation. Subsurface compaction below the normal tillage depth remains. Breaking subsurface compact soils has resulted in remarkable yield increase in several cases. In many of the cases farmers suspect of ‘subsurface compaction’ in their field but have no idea of measuring it. A diagnostic tool that easily helps a farmer to diagnose subsurface compaction is an soil penetrometer also know a soil compaction meter.  This tool will easily help you determine if subsoiling compaction exists and at what depth. A penetrometer is a 30-degree circular stainless steel cone with a steel shaft and a pressure gauge. The gauge reads in pounds per square inch (psi). To detect soil compaction penetrometer is pushed into the soil at the rate of 2.5cm per sec. Reading between 400 to 500 psi indicates potential soil compaction. Repeat the test ensuring the areas compared have similar soil moisture content.

Deep tillage is only a temporary measure and an expensive one, besides there are plenty of adverse effects of deep tillage while combating subsurface compaction. So it is imperative to conduct a penetrometer test periodically to determine chances of possible soil compaction and take necessary preventive measure to prevent soil compaction. Any practice that naturally improves soil structure and decreases bulk density should be employed.