Module 6:

6.3 Soil science

6.3.1 Plant nutrition

1   Magnesium

This might typically only be needed in sand specification pitches or very sandy soil profiles. A deficiency might show up as leaves being less green than expected, also showing up as yellowing between the leaf veins, but with the veins appearing green. The older leaves will also have a reddish tinge around the leaf margin, similar to calcium deficiency, but neither of these are common deficiencies in soil based football pitch situations.

2   Iron

This micro-nutrient is used mostly used for improving greenness of colour, especially when grass growth is limited over the autumn and winter period. If iron is supplied as sulphate of iron it can also help create a more acidic surface layer to discourage weeds and diseases: Be careful not to apply excessive quantities of sulphate of iron because this can create a very acidic surface layer which is detrimental to pitch quality. A lack of iron will be seen as a lack of green colour, especially in between the leaf veins, but just like magnesium this is a much less common deficiency in turfgrasses.

3   Other nutrients

Any of the other eleven nutrients might also be included in a fertiliser product to aid the turfgrass plant in its growth and development, but in practice they will be more of an insurance policy because it is highly unlikely there will be a lack of those nutrients, especially where clippings are mostly let fly and returned to the sward rather than continually boxed off and removed, to provide for adequate grass growth.

The role nutrients play within a turfgrass plant are well researched and highlighted by products and supporting product literature. However, the need to routinely apply many of the essential nutrients can often be overplayed by marketing material, which is understandable as it is a means to support the sales of a product. This doesn’t mean that other nutrients are not needed, just not to the extent that is often portrayed. If, however, the fertiliser programme that is being used is producing the desired results, in a cost-effective way, and pitch playability and quality is being sustained then it would be questionable why someone would want to change the applied fertiliser programme, even if in theory some of the nutrients might not be needed, and especially if price differences between an ‘ideal’ fertiliser and the one being used is relatively small. The groundskeeper is usually best placed to make that type of informed decision.

Lots of nutrients are already present within soils and are also added to by topdressings. These nutrients are then also gradually made available to the grass plant by weathering processes, with further nutrients being provided from impurities in rain, irrigation water and atmospheric deposits.

Where a genuine nutrient deficiency is present then the addition of that nutrient as a fertiliser application will clearly be of benefit to the turfgrass plant. Carrying out regular soil tests for nutrient availability, combined with detailed pitch assessments will significantly improve the accuracy and effectiveness of decision making for what is needed in a fertiliser programme for a specific football pitch.

Special nutrient programmes will often be prepared for a high specification sand-based pitch, but these will only be used for higher quality, more intensively maintained pitches.

If someone is in any doubt or are uncertain about the need for some micro-nutrients, they can usually apply a biostimulant that often contains a wide range of these. These would typically be more than adequate for topping up any potential micro-nutrient deficiency.