Soil test interpretation and more: 4 seminars in Australia

I was in Sydney, Adelaide, and Brisbane this week to discuss the MLSN approach to soil test interpretation in four seminars organized by Living Turf.

In these seminars, I explained that the use of the MLSN guidelines is as simple as planning how many beers to buy for an upcoming party. And at this party, I want to ensure that I don't run out of beer to serve my friends.


This is a quick summary.

1: Soil test calibration involves establishing different levels of nutrients in the soil, growing a grass in those soils, and then evaluating the grass response to different levels of that nutrient. It quickly becomes apparent that these calibrations will be specific to the soil type, grass variety, and climate in which the calibration is done. Doug Soldat called these tests "expensive and time consuming." On a global scale, the word I use to describe this is impossible.

2: Because doing such extensive calibration is impossible, the conventional turfgrass guidelines were developed by adjusting the ranges from agricultural crops and soils:

"Traditionally, ranges for various nutrients are based on the past 60 years of fertility studies, particularly on forages, agronomic and horticultural crops, with adjustments made to fit perennial turfgrasses based on studies and the judgment of experienced university turfgrass scientists."

In addition to that, the conventional guidelines have in some cases been set deliberately high. That's not because grass performance would be improved by more nutrients, but because "the cost of fertilization was not considered of primary importance for turf." And that quote is right from the textbook.

3: The minimum levels for sustainable nutrition (MLSN) guidelines for interpreting soil tests take a different approach by focusing on the way turf is managed in the modern era, and considering grasses and the soil conditions used for high performance turfgrass today.

4: Use of the MLSN approach involves making an estimate of 100% of the nutrients that the grass can use, and increasing that by an additional amount to keep as reserve in the soil. One then compares the sum of the use estimate and the reserve quantity to the amount actually present, and the result of that comparison is the minimum fertilizer recommendation.

You can scroll through the slides below, or view or download them here.

After my seminar about MLSN, Daryl Sellar showed a demonstration of the TurfKeeper system. One can read about it at the website, and how it "becomes the home of all turf management planning, actions, and facility history." It starts with a job board and goes from there, with the tasks, costs, product usage, and application records all linked in a way that impresses me every time I see how TurfKeeper is used. I was recently listening to a podcast about turfgrass innovation. Dave Wilber and Kevin Hicks discussed the direction of the industry, and Kevin mentioned that there is a lot of data out there, and a lot of systems that do a good job of handling one aspect of the data. TurfKeeper puts it all together in a way that few others do.


The MLSN approach is suitable for any grass, soil, and use, because it involves both a site specific estimate of nutrient use plus a reserve amount to keep in the soil. I enjoyed seeing a range of turfgrass sites and grasses on this trip, and discussing with so many turfgrass managers the practical use of MLSN to interpret soil tests in those conditions.


That's kikuyugrass at Eagle Farm race course in Brisbane. For a good story about something that happened at Eagle Farm in 1984, read about Fine Cotton.


This is Legend green couch (bermudagrass) overseeded with perennial ryegrass at Suncorp Stadium.

A post-conference assortment

I made a few notes at the recent Philippine Golf Course Management Conference. I was there to speak about irrigation water and soil test interpretation.


The conference program was excellent and I learned a lot. Things I noted, which will perhaps be of interest:

  1. Do you know about this sand calculator from Purdue University?

  2. One of the speakers showed how the Turf Tracker improves the precision of product applications to the golf course.

  3. I was intrigued by the Zero Carbon Resorts program, and especially the Demonstration Cottage.

  4. There was some discussion of the Philippines Köppen climate classification.

MacKenzie's fundamental principle of greenkeeping

I taught two seminars yesterday at the Philippine Golf Course Management conference. The first was about irrigation water requirement. The slides are here, and I made this Shiny app with data from 2013 through 2016 for Manila, Cebu, and Baguio.


In the second presentation I spoke about MLSN after 5 years. I explained what soil test interpretation is, why the MLSN guidelines were developed, and explained how they work.

This surprised me

I was making some calculations today about irrigation water requirement. I looked at Manila, where the normal annual rainfall is 1877 mm, and Cebu, where the normal annual rainfall is 1260 mm. These data from Manila are the 30 year average from 1961 to 1990, and at Cebu a 20 year average from 1971 to 1990.

For my calculations, I was looking at the past 10 years, from 2007 to 2016. I wanted to show the variation in irrigation water requirement at both locations, based on a calculation of the daily soil water balance.



I was able to get the daily precipitation from the GHCN (Global Historical Climatology Network) daily summaries by using the rnoaa package in R. For Manila, the annual precipiation (summed from the daily amounts) for the past 10 years ranged from 1381 mm to 2932 mm, with a mean annual amount of 1908 mm. That's pretty close to the normal of 1877 mm. For Cebu, there wasn't as much rain. The lowest year of the past 10 had 682 mm, the most was 1713 mm, and the mean was 1276 mm. Also pretty close to the normal of 1260 mm.


So what surprised me? Cebu gets less precipitation than Manila. The year with the most precipitation (in the last 10 years) at Cebu still had less rain than an average year at Manila. With those kind of differences, I expected the irrigation water requirement to be more at Cebu than at Manila. It rains less at Cebu, so more irrigation should be required, right?

The calculations don't work out that way. The reason is the way the rain is distributed through the year. Manila has more pronounced dry seasons and wet seasons. Cebu has dry and wet seasons too, but the dry seasons have more rain than at Manila.

For more, see the full presentation.

My presentation on irrigation water quality

Yesterday I taught a seminar about irrigation water quality.

Here are some links related to that presentation.

Preventing nutrient deficiencies


The recording of my webinar on preventing nutrient deficiencies is now available in the videoteca section of the Campus del Césped website.

Or watch the English version right here.

This was fun. I hope you'll read the handout too. It is only 4 pages, with lots of white space, and gives a brief overview of this important topic. If you are still interested, then watch the video of the webinar at your leisure, and watch or download the slides too.

Links in English

Links in Spanish

This is a lot to fit into an hour

But I am going to try. I've got four things I want to explain in this upcoming webinar, and I have made some interesting calculations. Can calculations be provocative? Maybe these ones are provocative and interesting.

The Campus del Césped webinar is on 12 January at 17:00 Central European Time. You can register here.

Here is the 4 page pdf handout, in English.


These are the slides in English.

These are the slides in Spanish.

If you are are joining this webinar, you will find it useful to review the slides and handout prior to the event.

Optimum playing conditions, minimum inputs

"Mekong River diverted into Thailand's waterways, worrying drought-stricken neighbours like Vietnam," says a recent headline. "Drought exacts toll on crops in region," says another. And "China has embarked on an unprecedented 'water diplomacy' mission to alleviate the drought in Laos, Myanmar, Thailand, Cambodia, and Vietnam by discharging massive quantities of fresh water downstream from one of its dams," says a third article.


The recent R&A Seminars on Sustainable Golf Course Design, Renovation and Maintenance in Asia, held in early March in Beijing and then in mid-March near Bangkok, were timely in addressing the use of water (and other resources) on golf courses.

Selection_037At these seminars, I spoke about how one can optimize the playing conditions of the golf course while minimizing inputs of resources such as water.

This 12 page handout has details of what I discussed, and includes links to articles and all my presentations.

One of the easiest ways to reduce the amount of water required is to minimize the area of maintained turf.

Another way to reduce the water requirement is to use drought tolerant species. In particular, one can produce the best surfaces with the fewest inputs by using native species.

I also explained how to calculate the irrigation water requirement for any area of turf. First, estimate the water use by evapotranspiration, then subtract the quantity of effective rainfall and adjust for the surface area to be irrigated. Then, make further adjustments for the distribution uniformity of the irrigation system and the salinity of the water, and one is left with the quantity of water required as irrigation.

It is quite useful to have this number, and especially to make that calculation for a drought year. In that way, the necessary amount of water storage can be built, or one can adjust the turfgrass area or turfgrass species to make sure the golf course will be sustainable in terms of water.


If there isn't enough water for irrigation, then some grasses will die. Seashore paspalum is the grass that requires the most water to survive in Southeast Asia, and it dies when irrigation water is not supplied. Calculating the irrigation water requirement and planning to have that much water available can be quite useful. As this article states, regarding the current drought, and planning for water availability in such conditions:

Such long-term planning is unfortunately uncommon, say agriculture experts. Dr Leocadio Sebastian, a Vietnam-based regional programme leader for the Consultative Group On International Agricultural Research, says governments tend to be reactive. "They tend to favour relief intervention."

For golf course turf, one can't expect relief intervention, so it is better to plan ahead by choosing grasses that require fewer inputs.