Module 4:

4.4 How much is needed?

4.4.11 Soil acidifiers / soil conditioners

A football pitch has a soil pH of 7.0. The aim is to reduce this to pH 6.5. The material that is to be used can lower soil pH by 0.5 of a unit with an application rate of 200kg per hectare for the soil type on this pitch.

How much of the material is needed to reduce the soil pH to 6.5 on a 7,000m² pitch?

1   There can be an overlap between some products sold as biostimulants and soil conditioners, as the terminology can be interpreted in various ways. A good example might be a seaweed-based product which could be classed as both a biostimulant and soil conditioner. Let’s not worry about whether a product should be placed in one type or another though.

2   An example of a soil conditioner is Prestige W Conditioner which contains a low nutrient analysis (N : P₂O₅ : K₂O) of 2.6 : 0.8 :1, with 15.3% Saponin and 47.7% Organic matter, which also acts as a biostimulant. This has an application rate of 300 kg per hectare, so a 7,000m² pitch would therefore require 210kg, being supplied in 20kg bags.

3   An example of a soil acidifier is Sulphur 95, which is elemental sulphur (90% w/w sulphur) in mini-prill formulation. This has an application rate of 150 kg per hectare, so a 7,000m² pitch would therefore require 105kg, being supplied in 15kg bags. Reducing soil pH by 0.5 units might require 100-150 kg per hectare applied in the autumn. This might be desired if a football pitch soil was at pH 7.0 with high earthworm activity at the surface.

4   Care always needs to be taken when using acidifying products, because the surface can become excessively acidic. This can be an unintended consequence, especially in the short term as the product gradually dissipates throughout the soil. Carrying out trial rates would usually be recommended to ensure the soil does not produce an undesirable acidic reading, which affects the quality of the playing surface.