What is the difference between a soil amendment and a fertiliser?

25/01/2018

The purpose of soil amendments – or conditioners – and fertilisers are to help plant growth. However, did you know that they work in very different ways?

The contents and condition of the soil can strongly influence a plant by either limiting or increasing growth. By using either a soil amendment or a fertiliser, the soil can be altered to promote increased plant growth.

Let’s take a look at the differences between the two:

Soil Amendments

Although a soil amendment does not add concentrated nutrients to the soil, it improves the structure and texture of soil. The improvements made are increased air pockets and water flow, allowing the plant roots to grow further in search of nutrients in the soil. Some soil amendments, such as the soil conditioner SafeRock® Minerals (SRM), can also add micronutrients to the soil, which are not available from fertilisers.

Fertiliser

A fertiliser is a concentrated amount of nutrient added to the soil. This is added to directly improve plant growth, however, it does not contribute to improvements in soil structure or health. Without a healthy soil, added fertiliser nutrients can more easily run off the soil as the soil cannot absorb the nutrients.

In our previous post, we looked at the risks of using chemical fertilisers on the environment. Click here to find out more about their impact on agricultural sustainability.

Other points to consider

Plants do not just absorb nutrients in the raw form. For plants to be able to absorb nutrients from the soil, microorganisms need to turn these nutrients into a usable form. Microorganisms will only be present in soil that has a friable texture and lots of moisture -this can be aided by soil conditioner.

SafeRock® Minerals is our soil conditioner, providing an essential range of micronutrients and trace elements, including sulphur, calcium and magnesium. Use of SRM improves water retention and water and nutrient holding capacity of sandy and clay soils.

To summarise, fertilisers have a direct effect on plant growth by improving the supply of nutrients in the soil. They act as a ‘quick boost’ of macronutrients for plants.

By contrast, soil amendments indirectly impact plant growth as they work to improve soil health instead, providing the micronutrients that plants need.

 

Want to learn more about SafeRock® Minerals? Please get in touch with our team.