Example GC soil nutrient analysis
and report
May 30, 2023

Micah Woods, Ph.D.
Chief Scientist
Asian Turfgrass Center

Room 3602 Level 36 Tower 1, Enterprise Square Five, 38 Wang Chiu Road, Kowloon Bay, Hong Kong
www.asianturfgrass.com

Contents
1Notes and recommendations
1.1 Recommendation summary . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2 Chart legend . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2232Greens
2.1 Summary charts for greens . . . . . . . . . . . . . . . . . . . . . . . . . .

45A About this report

7B Lab Data

8C Site temperature summary

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Figure 1: The annotations on this example chart show the information that you’ll see on
the summary soil test result charts.

1

Notes and recommendations

1.1

Recommendation summary

At this soil pH, I recommend a low rate of CaMg(Co3 )2 to supply a little Ca and Mg andto keep the soil pH from dropping lower. I recommend adding dolomitic limestone ata rate of 25 g/m2 this year.
The soil P remains at a high level of 169 ppm. There is no need to apply any P
fertilizer this year. At the soil K level of 56 ppm, I recommend adding an N:K ratio of
3:1 this year.
The micronutrients are all at above average levels in the soil. There is no need tosupply micronutrients this year.
Please let me know any questions about this report and about my recommendations.

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1.2

Chart legendThis sample chart in Figure 1 shows how the data are presented for your samples fromeach area. When I look at these charts, I’m looking at three main things.
I look at the change over time (assuming you have a time series of samples). Is thetest result for a particular soil parameter going up, down, or staying the same? I also
look at how each parameter compares to the average from the area or zone1 for samples
in ATC’s dataset from the most recent five years. For elements with an MLSN minimum,that value is shown on the charts as well, and I check if the element is above the MLSN
minimum, or if the expected nutrient use over the upcoming year may drop the soil
level below the MLSN value.

1

I group greens together, fairways together, tees together, and rough & lawns together.

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2

GreensThis is a summary and recommendations for the 6 samples from the greens.
pH The range is from 5.5 to 6.1 with a median of 5.8. This is an optimum level for soil
nutrient availability and soil microbial activity.
Organic matter The average is 1.7%. This is a normal level for golf course puttinggreens.
Potassium The average is 56 ppm. See the notes and recommendations section at thestart of the report for the K recommendation.
Phosphorus The average is 169 ppm. See the notes and recommendations section at
the start of the report for the P recommendation.
Calcium The average is 587 ppm. This is more than enough to meet the grass requirements. Calcium fertilizer is not required.
Magnesium The average is 54 ppm. This is more than enough to meet the grass requirements. Magnesium fertilizer is not required.
Sulfur The average is 11 ppm. This is above the minimum guideline of 7 ppm. No S
fertilizer is required this year.

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AAbout this report
1. 1 ppm is 1 part per million. This means 1 mg of the element per 1 kg of soil (1mg/kg).
2. All soil test results and fertilizer recommendations are elemental amounts unlessotherwise stated. This is particularly relevant to phosphorus and potassium, inwhich this report refers to elemental amounts, but fertilizer labels usually report
phosphate (P2 O5 , 44% P) and potassium oxide (K2 O, 83% K). Please make adjustments as necessary for fertilizer application.
3. The phosphorus saturation ratio (PSR) is a calculated index for the risk of P leachM3ing. The formula is PSR= AlM P3 +F
eM 3 with the PM 3 , F eM 3 , and AlM 3 expressedas the Mehlich 3 (M3) extractable amounts in units of mmol kg-1 . This is basedon “Soil Testing to Predict Phosphorus Leaching.”2 If the PSR is above 0.2, you
can consider that P has a high probability of leaching from that soil. If the PSRis higher than 0.2, you really want to be careful—I mean don’t add any—about theapplication of P.
4. Sodium is included on the charts as an indicator of soil salinity. For cool-season
grass, I recommend keeping the sodium below 120 ppm. If you have Na less than120, no problem. If the Na is above 120 and you are growing cool-season grass,you’ll want to consider leaching the salt from the soil. For warm-season grasses,excellent turf can be produced with Na of 200 or 300 ppm. However, if your salinity
is that high, I recommend using an EC meter to monitor irrigation water and soil
salinity to ensure it is kept at an acceptable level.
5. The predicted N mineralization by month for the next year is based on equations
from Gilmour & Mauromoustakos (2011),3 using average temperature information for your location, and assuming that the area is irrigated. More informationon the recent temperatures at your site are presented in Appendix C.

Generated with ATC’s soil-report 0.4.0 & typeset in XƎLATEX. Feature requests & bug reports at atc-soil-report.
2Maguire, R.O. and J.T. Sims. 2002. Soil testing to predict phosphorus leaching. J. Environ. Qual.
31:1601–1609.
3Gilmour, J.T. and A. Mauromoustakos. 2011. Nitrogen mineralization from soil organic matter: asequential model. Soil Sci. Soc. Am. J. 75:317–323.

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Example GC

Example GC

C

Site temperature summary

The charts in this section show the temperatures at your location. The weather has acontrolling effect on how the grass can and does grow, and consequently the weatheralso has a big effect on grass nutrient use and on nutrient demand.
I’ve estimated the growth and nutrient use based on site temperatures. I have also
used these temperatures, combined with the most recent soil organic matter test results,
to estimate nitrogen mineralization.
The predicted N use and N mineralization and N fertilizer requirement are all estimates. You can consider them to be general guidelines that give an approximationof when the nutrient demand will be highest and lowest, and when the mineralization
may be at a peak. As for the exact numbers, take them as estimates. You’ll have to adjustthe N rates that you apply based on grass performance, in order to achieve the desired
growth rate and grass conditions.

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