Growth Potential

2nd Green this morning.

At Ealing we always trying to improve and like most industries, turf maintenance has evolved and is evolving all the time. On the agronomy side, getting the right fertility programme in place is crucial for having healthy, but playability greens. Nitrogen is the main element applied to playing surfaces, but this nutrient is so hard to judge. Over apply and you end up with slow, thatchy greens. Under apply and turf lose can occur. For many years agronomists have talked about the 'magic line'. This is when you are in complete control of your grass growth and eliminate peaks and troughs. But how do you achieve this when so many variables are around such as the weather and temperature?

This year we have decided to 'tweak' the fertility programme slightly at EGC. The aim has been to get as close to that magic line as possible without affecting the agronomy side of the greens (and of course how they putt). In general there are four things that a grass plant will need to allow it to grow. Fertility, water, temperature and light all play their part. We can control fertility pretty well now with soluble Nitrogen applied instead of granular fertiliser. Then if it grows too well, suppressants such as trinexapac-ethyl will calm it down. Water can be monitored with a modern valving head water system, along a weather station and moisture probe to allow you to gauge the soil conditions. Light is a tough one. Especially on a Parkland course, your hands can be tied to a certain extent (unless you are Augusta and have artificial light!). The last one leaves temperature and over the season this dictates a huge amount of the potential of the plant. This is where a newish method called 'Growth Potential' comes in!

An american agronomist called Micah Woods has been writing about this for a while. http://www.files.asianturfgrass.com/201306_growth_potential.pdf It basically relates temperature to the potential of growth. But we know all this we hear the cries! How do we monitor and control it? He has set a threshold for cool season grasses such as ours at around 20C and anything above or below affects growth. So for instance if the average for July was 20C, then the grass has the potential to grow at its maximum rate. But if the temperature drops by say 8 degrees this could drop the potential by over half.

What does this mean for Ealing? Well by using this method it could allow us to control growth to as close to that 'magic line' as possible. We already have a modern water system and have a weather station and moisture probe. So we are in control of our moisture needs. We control Nitrogen inputs with external nutrient tests. Light is out of our hands at present. So that just leaves temperature. For this we implemented the GP system and at the start of the year we set up a spreadsheet. Depending on temperatures, we applied a certain amount of Nitrogen depending on what that spreadsheet told us. Straight away we could see that over the years at certain times (namely the spring), we have over applied this nutrient. This method has been going now for 5 months and the results so far have been interesting:
 

	Period	2012	2013
Nitrogen	Jan to May	91kg	31kg
Potassium	Jan to May	78Kg	23kg
Smoothness	May	9.1 out of 10	9.5 out of 10
Speed	May	9.4	11.7
Rainfall	May	38.8mm	49.8mm

These figures were taken until the end of May in both of those years. Straight away you can see that we have used around a third of Nitrogen and Potassium in 2013 (only nutrients applied to the greens) and smoothness and speed has increased. The reason why we put rainfall in there is that many would believe that May of last year was wetter and that's why speed and smoothness was down. But looking at those figures you can see that actually it was wetter this year, but speed rose to 11.7 feet from 9.4!

So our conclusions so far are very positive. We have used less fertiliser (as we had the coldest spring for 50 years), but our performance was better. It will be interesting to see how this runs over the season and we will report back at the end of the year. For now the signs are looking as good as the greens!