I went to Korea this week to teach about turfgrass nutrient requirements and the new MLSN guidelines. I taught for 4 hours as part of the 2014 Sky72 Winter Seminar, explaining how these 5 principles can be used to ensure any turfgrass, anywhere in the world, maintained to any standard, can be supplied with just enough of each essential nutrient:

1. The elemental content of fertilized turfgrass leaves is relatively constant
2. The amount of nitrogen supplied to the grass controls growth and uptake of other nutrients
3. A temperature-based growth potential can predict how much nitrogen the grass will use
4. The grass cannot use more nitrogen than is applied as fertilizer
5. The MLSN (minimum levels for sustainable nutrition) guidelines ensure that soil nutrient levels remain high enough to produce excellent turf conditions

Sky72 is the host of multiple professional tournaments each year and it was great to spend some time at this facility. We had lunch at the amazing Dream Golf Range, a circular driving range with hundreds of hitting platforms. It was (perhaps still is?) the world's largest driving range. If you've flown into Incheon, Sky72 is the course (4 actually) right at the airport. You may have seen this video produced by the course staff:

The next day, I was at the Korea Golf Industry show to speak with the Turfgrass Society of Korea about a similar topic.

In a presentation I called A Modern Method for Determining Turfgrass Nutrient Requirements, I explained how an estimate of nutrient use, combined with the MLSN guidelines, and with a measurement of the nutrient levels in the soil, allows a turfgrass manager to know exactly how much of each nutrient must be supplied. 

We can be confident that good performing turf can be produced in soils with nutrient levels at or above the MLSN guidelines. To ensure the soil remains at or above the MLSN guideline, we can determine the fertilizer requirement for any element by subtracting the amount present in the soil from the amount at the MLSN guideline added to the estimated harvest of that element by the grass.

See the slides from that presentation here: