Nutrition is only one of the factors contributing to a strong, healthy sward, but it is an important one. And it’s essential to get it just right. Applying too little fertiliser will result in poor growth. Applying too much gives lush, soft growth. In both cases the risk of disease increases and the appearance and playability of the sward is unsatisfactory.
There are many aspects to consider when designing a fertiliser programme. It is important to recognise that, even though a single soil type might be present, there can be significant variation in nutrient levels across one sports facility. In addition, the type of grass will affect nutrient requirements — as will shade, slopes and volume of traffic.
In spring the main aim should be to help the grass come into growth and then to maintain steady, healthy growth throughout the season. A few years ago it would have been the norm to give the grass a wake-up call with a dose of straight fertiliser — probably 18-0-0. Now the trend is towards fertilisers with a bit of potash as well as nitrogen and that release in a steady pattern.
Straight mineral fertilisers tend to promote the soft, lush growth that attracts and encourages disease and that can be severely “knocked-back” by a late spell of cold weather. They also tend to leach quickly.
It is partly the chemistry of the fertiliser that determines its likely retention in the soil. The right chemistry will help reduce leaching and, while the plant may have to work a little harder to get at the goodness, the result tends to be sturdier and shorter-jointed growth rather than soft, elongated blades.
“A lot of turf managers are using low nitrogen levels with more potash and perhaps a smidgen of iron to give steady growth and improve turf in the spring,” says commercial development manager Clive Williams at Vitax. “We are looking at fertilisers that are retained in the soil in an ammoniacal rather than a nitrate form, as the ions will keep it in the soil.”
Autumn and winter can be a tough time for turf. The grass needs to be strong to withstand the elements and to fight stress and disease. Fertiliser programmes in the autumn and winter are likely to use products with lower nitrogen content than those used in summer. Potash helps produce a sturdy plant but is also a mobile nutrient that can be easily leached with heavy winter rains. Many autumn/winter fertilisers will also contain iron to harden the turf, promote a bit of colour and boost the plant’s immune system to fight disease.
It is important to spend time choosing the right formulation. In wet conditions granules can be carried away from the site on the soles of shoes and the bottom of machinery. Granules can also be wasted into the clippings box where the height of cut is maintained very low. Mini granules and powered fertilisers are best in these situations.
Liquid feeds are useful for supplementary feeding as they provide plant food in a readily available form to give a quick response. While such feeds used to be applied in the late spring and summer, a lot of turf managers are now using liquids all year round because they can supply small amounts of nutrients regularly and have more control.
Whatever products you choose, don’t forget to check the nutrient analysis in combination with the application rates and make sure that the product is uniform throughout so it spreads evenly.
If you are looking for topdressings, an important factor to consider is the purpose. Do you want a level surface, to increase the organic content or return nutrients to the soil? The topdressing needs to be compatible with the rootzone mix and should have the required characteristics in terms of pH, particle size, uniformity and sterilisation.
Have you registered with us yet?
Register now to enjoy more articles and free email bulletinsSign up now