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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