Noel Mackenzie: What fertilisers should greenkeepers use?

Alistair Dunsmuir
By Alistair Dunsmuir October 30, 2011 14:51

Noel Mackenzie: What fertilisers should greenkeepers use?

• How does a greenkeeper get the best out of his course?

• What technologies are out there to aid him or her in their work?

• What is there to know about the products on offer and when to use them to best effect?

These questions are natural ones for the greenkeeper looking to self improve; something all greenkeepers are keen to do, in my experience. There is a significant need for good greenkeepers in our profession these days, though the cavalier way some clubs behave with their course managers and head greenkeepers makes me wonder if I am the only one to think so. The good greenkeeper will reflect on events, how he/she responded to them and whether the results of their, and their team’s, labours had the desired effect. Inevitably, this year will see some significant retrospective focus on fertiliser inputs.

Before examining the subject in depth it is important that a user knows his fertiliser. It is not enough simply to accept that a bag of ‘X’ or ‘Y’ product makes the grass grow and look good. The technology in some fertilisers now is very advanced, having been developed to give market advantage to the companies selling the products. Much of the research in this area is focused on in-house commercial research and a good deal of money and time is spent on getting products to do ‘what it says on the tin’. Nevertheless, it is true to say that some of the information pumped out is overly complex and bewildering and some sales are driven by ‘blinding with science’.

Let us remember why we fertilise grass. Largely it is a case of replacing nutrients removed by mowing of clippings and other mechanical treatments, volatilisation (nutrients turning to gas and drifting into the air) and leaching. Rarely do greenkeepers seek to increase plant production to the levels required in agriculture for the aim is simply to allow the turf to replenish itself without excessive growth. Most greenkeepers beyond their first few months learn that over feeding is best avoided for a host of good reasons.

On the tin, bag or box the NPK ratio blurts out the often perceived essential information. Fertilisers are often described in these terms but this tells us very little about how they behave in the environment. Some ingredients are readily available and are almost immediately soluble and available to the plant whereas others slowly release their nutrient under specific conditions. This is the important information; it is not helpful knowing how much percentage or type of nutrient is present if you do not understand the source of the nutrient. The nutrient may be released in a day or so or be released in a controlled manner over a period of weeks and sustained for as much as nine months or more.

In fine turf management of cool season, grasses basic greenkeeping lore dictates low nitrogen feeds in winter and more in spring/summer. This reflects the growth pattern of the plant … or rather it did traditionally when winters were winter-like and springs were, well, spring-like!

Beyond knowing the fertiliser products available and which does what and how quickly and what it contains and whether it is acidifying or alkaline in nature, the fundamental factor in deciding which is the most appropriate product for you is your surface. The variables are endless but, to simplify, in the UK, in relation to fine turf, we are likely to be thinking in terms of the following factors:

Grass type: poa annua – annual meadow grass in annual and perennial and reptans forms; agrostis capillaris – browntop bent; agrostis castellana – highland bent; agrostis canina – velvet bent; agrostis stolonifera – creeping bent; festuca rubra commutata – chewings fescue; and festuca rubra litoralis – slender creeping red fescue. We might even consider Lolium perenne (turf type perennial ryegrass).

The management issues are wear, cutting height, cutting frequency, verticutting/scarifying regimes, renovation policy, topdressing arrangements, irrigation water pH and calcium content, use of supplements, thatch issues, problem pests (for example moss, worm casting and so on) and the disease susceptibility of your greens.

The environment would be a wet or drier climate, shaded, tree surrounded, windswept or protected, salt spray/saline water presence, and with good or bad drainage.

And the construction / drainage method could be links sand greens, USGA constructions (good, the bad and the ugly imitations as well), ‘push-up’ greens of varying soil types, ‘dew pond’ greens (a variation on push up greens?), pure sand greens, rootzone greens, greens with a myriad of topdressing types within them, greens with good drainage or greens with waterlogged soils at times.

These lists could go on … the important thing is that the impact of each of these issues on the turf will have some degree of bearing on the fertiliser programme, or at least it should. The other factor not mentioned so far is that of human experience, we are a huge factor in shaping our own decisions. We are bound by our own experiences and perceptions. Our experiences limit us and with so much at stake make us cautious of trying the new and unproven. Our perceptions can be unreliable; a green can look great in sunshine but on a cloudy damp day just 24 hours later we might be hitting the panic button. Rain can transform a green in 15 minutes. We need to be on our guard.

Obviously, to get the best out of our greens (and other surfaces) we need to use optimal products to achieve the most desirable outcomes. The correct product will therefore be contingent on the circumstances which we are managing (contingency theory of management).

The greenkeeper will therefore have to consider if for his greens he should opt for: controlled release, organic based, microbial inoculated, conventional (organic/inorganic mixes) or liquid fertilisers (fast acting soluble or slow release organic or quasi organic formulation).

Modern trends within fertilisers are for greater specialisation. Many greenkeepers now successfully use a controlled release feed through the winter with minimal shortcomings due to the advances in technology as how the nutrient is provided. Alternatively, the same greenkeeper might achieve the same growing and condition results in his turf by using a regular liquid feeding programme. Neither may be better than the other in terms of grass performance and condition but one management system may suit the course better on the basis of staff availability or some other factor.

That is not to say that all fertiliser regimes that deliver the same nutrient inputs are the same! It is possible to apply the wrong fertiliser regime that may not aid a difficult situation, indeed it may compound it! For example, if a green is suffering from black layer and reduced anaerobic conditions it may not aid the situation if a high sulphur content fertiliser is used as this will fuel the anaerobic production of hydrogen sulphide further. Granted, the primary problem will be due to soil air contents and diffusion which are normally impeded by poor drainage, but the incorrect feeding regime might make a bad situation worse. The green may require draining to overcome the fundamental problem but why make it worse? The same sulphur content fertiliser after the green is drained may even be beneficial to it – but only if the conditions in the ground are changed by drainage!

Managers, head greenkeepers and course managers need to evaluate their fertiliser regimes to assess them for technical turf suitability. Other management decisions may alter their turf ‘ideal’ fertiliser to one that fits also with other parameters such as operational capabilities, management objectives such as aiming to change sward type and so on.

Alistair Dunsmuir
By Alistair Dunsmuir October 30, 2011 14:51
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