A Method for Estimating Turfgrass Nutrient Requirements: a report from the Icelandic Greenkeepers Association meeting

On my first visit to Iceland, I spoke at a meeting of the Icelandic Green- and Groundskeepers Association at beautiful Keilir Golf Club in Hafnarfjörður.

I described a 5 step method for estimating turfgrass nutrient requirements. Accurate estimates of turfgrass nutrient requirements ensure that turf is supplied with enough of each element that it requires, so that the turf can perform at a high level. At the same time, this process ensures that the growth rate of the turf is controlled, and that excessive fertilizer applications are avoided.

The 5 steps, which are explained in detail in the slides and accompanying 4 page handout, involve these core priniciples:

1. The elemental content of fertilized turfgrass leaves is relatively constant
2. The amount of nitrogen used by the grass controls growth and uptake of the other nutrients
3. A temperature-based growth potential can predict how much nitrogen the grass can use
4. The MLSN ensure that soil nutrient levels remain high enough to produce excellent turf conditions
5. By considering the previous points, mathematically, the minimum nutrient requirement can be determined

Nutrient requirements and turfgrass growth potential are closely linked to soil nutrient guidelines. At the seminar, I mentioned the Global Soil Survey (GSS), the citizen science initiative that enlisted turfgrass managers from around the world in the development and refinement of new soil nutritional guidelines. The GSS is now completed, and you can read the full report and see the data here.