Soil TestsSoil Tests

- Basis for Soil Testing- Basis for Soil Testing

- Result Interpretation- Result Interpretation

Why Carry Out a Soil Why Carry Out a Soil Test?Test?

Aid in providing the optimum availability Aid in providing the optimum availability of nutrients for turf growthof nutrients for turf growth

Identifies nutrient deficiencies and Identifies nutrient deficiencies and problems which can be addressed before problems which can be addressed before a maintenance program is initiateda maintenance program is initiated

Opportunity to Opportunity to createcreate and/or and/or maintainmaintain optimal soil chemistry for turf growthoptimal soil chemistry for turf growth

Benefits of Soil TestingBenefits of Soil Testing Optimise plant healthOptimise plant health

Reduce unnecessary maintenance practices Reduce unnecessary maintenance practices and fertiliser applicationsand fertiliser applications

Opportunity to save both time and moneyOpportunity to save both time and money

Removes guesswork from formulating fertiliser Removes guesswork from formulating fertiliser programsprograms

Sampling ProcedureSampling Procedure Reliable results depends on correct Reliable results depends on correct

samplingsampling

Aim to provide a representative sampleAim to provide a representative sample

Sampling depth important due to profile Sampling depth important due to profile horizon variationhorizon variation

Sampling InstructionsSampling Instructions Approximately 200g of soil Approximately 200g of soil

necessary for nutrient analysisnecessary for nutrient analysis

Depth of cores should measure Depth of cores should measure 10cm10cm

Small cores more suitable than hole Small cores more suitable than hole changer- sized coreschanger- sized cores

Sampling Instructions cont.Sampling Instructions cont.

Take samples from areas of average growthTake samples from areas of average growth

Take cores from poorer spots only if they areTake cores from poorer spots only if they are numerousnumerous

Cores should not be taken from recently Cores should not be taken from recently fertilised areasfertilised areas

Time of year is important for historical analysisTime of year is important for historical analysis

Soil Properties AnalysedSoil Properties Analysed Soil pH (water, and CaClSoil pH (water, and CaCl22))

Cation Exchange Capacity (CEC) or Sum of Cation Exchange Capacity (CEC) or Sum of CationsCations

Total Soluble Salts (TSS)/Electrical Total Soluble Salts (TSS)/Electrical Conductivity (EC)Conductivity (EC)

Phosphorus (Olsen)Phosphorus (Olsen)

Soil Properties Analysed Soil Properties Analysed cont.cont.

Potassium (Skene)Potassium (Skene)

Ca/Mg RatioCa/Mg Ratio

% Base Saturation Ca, Mg, Na, K% Base Saturation Ca, Mg, Na, K

Interpretation of ResultsInterpretation of Results Results interpreted specifically in relation Results interpreted specifically in relation

to turf growthto turf growth

Turf has specific nutrient requirements Turf has specific nutrient requirements and tolerance to toxicities of various and tolerance to toxicities of various elementselements

Turf UseTurf Use is used to assist in determining is used to assist in determining recommendationsrecommendations

pHpH

Method Ideal Range Eg Remedial Treatment

pH(H2O) 6.0-7.5 5.0 Apply lime at 10kg/100m2 (2applications, 1 month apart)

7.0 No action required

8.0 Apply granulated sulphur andCheminel Trace Element Mix

pH(CaCl2) 5.5-7.0

Total Soluble Salts (TSS)/ Total Soluble Salts (TSS)/ Electrical Conductivity(EC)Electrical Conductivity(EC)

Reports the TSS in parts per million and Reports the TSS in parts per million and the EC in dS/m.the EC in dS/m.

TSS(ppm) = EC (dS/m) x 2970TSS(ppm) = EC (dS/m) x 2970

Ideal TSS level is <1000ppm or EC<0.34Ideal TSS level is <1000ppm or EC<0.34

SalinitySalinity

Rating EC (dS/m) TSS (ppm) Remedial Treatment

Low <0.3 <900 No treatment required

Moderate 0.3-0.5 900-1500 Improveinfiltration/drainage

High 0.5-1.0 1500-3000 Check the EC ofirrigation water

Very High >1.0 >3000 Apply gypsum

Cation Exchange Capacity Cation Exchange Capacity (CEC)(CEC)

Is equal to the sum of the of the 4 major Is equal to the sum of the of the 4 major cations (Ca, Mg, Na, K) measured in milli-cations (Ca, Mg, Na, K) measured in milli-equivalents/100g equivalents/100g

Is largely dependent on soil typeIs largely dependent on soil type

low CEC:low CEC: < 4 meq/100g (sands)< 4 meq/100g (sands) moderate CEC:moderate CEC: 4-10 meq/100g (loams)4-10 meq/100g (loams) high CEC:high CEC: >10 meq/100g (clays)>10 meq/100g (clays)

To Raise CECTo Raise CEC

Incorporate organic matterIncorporate organic matter

Increase % of loam and clay-sized Increase % of loam and clay-sized particles in soilparticles in soil

Phosphorus (P)Phosphorus (P)Level Olsen

(ppm)Remedial Treatment

Very Low <7 Apply Starter fertilisers, high Pfertilisers such as MAP or DAP or

SuperphosphateLow 7-18 As above at lower rates.

Adequate 18-35 No action required

High 35-300 No action required

Very High >300 No action required

Potassium (K)Potassium (K)

CEC of Soil Optimum Level(Skene method)

Low 100-120 ppm

Moderate 130-150 ppm

High 160-190 ppm

Base SaturationBase Saturation

Used to assess the levels of Ca, Mg, Na Used to assess the levels of Ca, Mg, Na and K as percentages of the total CEC.and K as percentages of the total CEC.

Optimum Extractable level of an ion such Optimum Extractable level of an ion such as Ca is dependent on the CEC of the soilas Ca is dependent on the CEC of the soil

Presenting levels as Base Saturation (or % Presenting levels as Base Saturation (or % of CEC) eliminates the need to consider of CEC) eliminates the need to consider CEC.CEC.

Recommendations based on ideal ranges Recommendations based on ideal ranges of % base saturationsof % base saturations

Base SaturationsBase SaturationsElement Ideal Range

(%)Remedial Treatment

Ca 65-70 Apply Gypsum ifdeficiency exists

Mg 15-20 Apply MagnesiumSulphate if deficiency

exists

Na (ESP %) <6 Apply Gypsum ifhigher*

K 5-10 Apply Potassiumsulphate if deficiency

exists

Ca/Mg RatioCa/Mg Ratio

Low:Low: <2<2 Apply GypsumApply Gypsum

Optimal:Optimal: 2-52-5

High:High: >5>5 Apply DolomiteApply Dolomite

Remedial ActionRemedial Action

Products used in remedial treatments Products used in remedial treatments can have complimenting or conflicting can have complimenting or conflicting effects on other soil properties.effects on other soil properties.

Must take into account this range of Must take into account this range of effects when recommending remedial effects when recommending remedial action.action.

Eg. Treatment of pH can effect the Eg. Treatment of pH can effect the Ca/Mg RatioCa/Mg Ratio

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

ratioratiopH Low(<5.0) Acceptable

(5-7) High (>7.0)

Ca/Mg

High (>5.0)

Magnesium carbonate

Magnesium sulphate

Magnesium sulphate and ferrous sulphate

Acceptable (2-5)

50/50 Lime and Dolomite

No action Ferrous sulphate

Low (<2.0)

Lime Gypsum Gypsum plus ferrous sulphate

Nutrition TargetsNutrition Targets

Soil Mix pH E.C dSm P mg/kg Na %CEC K %CEC Ca %CEC Mg %CEC O.M%

A 5.5-6.5 <0.3 17-35 <5 5-15 65-75 12-20 2-2.5

ConclusionConclusion

Soil testing is an important tool for Soil testing is an important tool for turf management.turf management.

Results are most useful prior to Results are most useful prior to renovation, but can be conducted renovation, but can be conducted year roundyear round