1. - Basis for Soil Testing - Result Interpretation
Soil Tests
- Basis for Soil Testing
- Result Interpretation

2. Why Carry Out a Soil Test?
Identify nutrient deficiencies in the soil.
Identify problems which can be addressed before a maintenance program is initiated on a particular soil.

3. Benefits of Soil Testing
Optimise plant health
Reduce unnecessary maintenance practices and fertiliser applications
Opportunity to save both time and money
Removes guesswork from formulating fertiliser programs

4. Sampling Procedure Reliable results depends on correct sampling
Aim to provide a representative sample
Sampling depth important due to profile horizon variation

5. Sampling Instructions
Approximately 200g of soil necessary for nutrient analysis
Depth of cores should measure 10cm
Small cores more suitable than hole changer- sized cores

6. Sampling Instructions cont.
Take samples from areas of average growth
Take cores from poorer spots only if they are numerous
Cores should not be taken from recently fertilised areas
Time of year is important for historical analysis

7. Soil Properties Analysed
Soil pH (water, and CaCl2)
Cation Exchange Capacity (CEC) or Sum of Cations
Total Soluble Salts (TSS)/Electrical Conductivity (EC)
Phosphorus (Olsen)

8. Soil Properties Analysed cont.
Potassium (Skene)
Ca/Mg Ratio
% Base Saturation Ca, Mg, Na, K

9. Interpretation of Results
Results interpreted specifically in relation to turf growth
Turf has specific nutrient requirements and tolerance to toxicities of various elements
Turf Use is used to assist in determining recommendations

10. pH

11. Total Soluble Salts (TSS)/ Electrical Conductivity(EC)
Reports the TSS in parts per million and the EC in dS/m.
TSS(ppm) = EC (dS/m) x 2970
Ideal TSS level is <1000ppm or EC<0.34

12. Salinity

13. Cation Exchange Capacity (CEC)
Is equal to the sum of the of the 4 major cations (Ca, Mg, Na, K) measured in milli-equivalents/100g
Is largely dependent on soil type
low CEC: < 4 meq/100g (sands)
moderate CEC: 4-10 meq/100g (loams)
high CEC: >10 meq/100g (clays)

14. To Raise CEC Incorporate organic matter
Increase % of loam and clay-sized particles in soil

15. Phosphorus (P)

16. Potassium (K)

17. Base Saturation
Used to assess the levels of Ca, Mg, Na and K as percentages of the total CEC.
Optimum Extractable level of an ion such as Ca is dependent on the CEC of the soil
Presenting levels as Base Saturation (or % of CEC) eliminates the need to consider CEC.
Recommendations based on ideal ranges of % base saturations

18. Base Saturations

19. Ca/Mg Ratio Low: <2 Apply Gypsum Optimal: 2-5
High: >5 Apply Dolomite

20. Remedial Action
Products used in remedial treatments can have complimenting or conflicting effects on other soil properties.
Must take into account this range of effects when recommending remedial action.
Eg. Treatment of pH can effect the Ca/Mg Ratio

21. E.g. Remedial Treatments knowing the pH and Ca/Mg ratio

22. Nutrition Targets Soil Mix pH E.C dSm P mg/kg Na %CEC K %CEC Ca %CEC
Mg %CEC
O.M% A
<0.3
17-35
<5
5-15
65-75
12-20
2-2.5

23. Conclusion Soil testing is an important tool for turf management.
Results are most useful prior to renovation, but can be conducted year round