DOES INNOVATION BEAT TRADITION WHEN IT COMES TO FEEDING OUR GREENS?

Growth Potential & Data Article for Irish Golfer, May Edition

Does innovation beat tradition when it comes to feeding our greens?

It doesn’t take a greenkeeper to tell you that grass starts to grow in the spring, grows even more in the summer, before then falling back in autumn and winter. It’s a straightforward seasonal pattern against which greenkeepers have had to manage for generations. It’s also a pattern that has traditionally been mirrored by greenkeepers’ in their applications of nutrition – with a granular fertiliser applied in March and April and a combination of granular and liquid feeds throughout summer into late autumn. In many cases through winter, grass receives minimal inputs.

Advances in science, research and technology have cast doubt on this traditional approach in favour of a more scientific and data-driven programme of turfgrass nutrition that can improve year-round performance in course standards and presentation.

Improving course quality year-round

First published in 2005 by acclaimed agronomists Larry Stowell and Wendy Gelernter, the Growth Potential Model defines the relationship between turfgrass growth and temperature. It is the method by which a numerical value (between 0 and 1) is placed on the ability of grass to grow at a certain temperature. Assigning a numerical value to the effect temperature has on growth is becoming a vital turf management asset to leading greenkeepers across the globe.

The Growth Potential Model helps calculate the amount of nitrogen required to provide healthy and high performing surfaces year-round. Geography dictates that Irish courses consist of cool-season grasses that benefit from an optimum growth temperature range of 16^oC -24^oC. As the temperature flexes either side of this range, so does the ability of our turfgrasses to grow. The impact of summer 2018 is still being felt, when extended periods in Ireland up and over this optimum range, coupled with low rainfall, stunted growth and caused damage some courses are only just recovering from.

Fertilisers are an expensive component in every Club’s agronomic plan, so applying the optimum amount at a given time is critical to operating a cost-efficient programme. Equally, surface performance can be impacted by too much or too little nitrogen. Finding the right balance between performance and agronomic health is a perennial headache for greenkeepers.

Challenging the status quo

Our team is currently working with two well-respected courses adjacent to Dublin Airport, Corrstown Golf Club and Forrest Little Golf Club. Using climatic records from the airport’s weather station, we calculate the Growth Potential for poa annua greens across a 12-month period. When findings are plotted on a graph (above), they illustrate how growth potential remains depressed below 0.25 until May, before spiking between June and September – a period during which nutrition application is vital. The model calls into question the traditional application of expensive granular fertiliser in March and October, a period in which the data suggests the grass does not require excessive levels of nitrogen.

What does this mean for golfers?

Unwanted consequences of overfeeding can include flushes of growth on greens, increased clippings and soft growth on fairways and a significant increase in the susceptibility of plant disease during a period of the year when disease pressure is at its highest. The reduction in fungicide availability places even greater importance on a balanced nutritional programme, but that is for another day.

Together with other essential maintenance practices, a balanced nutritional programme can deliver superior course performance, with results almost immediate. At both Corrstown Golf Club and Forrest Little Golf Club, the improvement in greens performance within one year of our adoption of the Growth Potential model was significant;

Golfers rely on greenkeeping teams to deliver an agronomic programme to clubs that provide the best possible course standards and presentation. Maintenance budget considerations are a battle faced by most clubs in Ireland. Using a scientific-based model, be it Growth Potential or otherwise, helps turfgrass managers plan a cost-effective seasonal programme that independent research demonstrates outperforms more traditional methods. While climatic conditions in any given year may give rise to changes in the plan, the use of such models is proven to work and provide great surfaces.

Aindriu Jackson is a Regional Superintendent at Carr Golf, providers of agronomy and course maintenance solutions to 17 golf courses throughout Ireland, using the ‘Growth Potential Model’ at its client venues since 2016.