soil testing procedures for biologically based systems raymond c. ward ward laboratories, inc...
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Soil Testing Procedures Soil Testing Procedures for Biologically Based for Biologically Based SystemsSystems
Raymond C. WardRaymond C. Ward
Ward Laboratories, IncWard Laboratories, Inc
Kearney, NebraskaKearney, Nebraska
www.wardlab.comwww.wardlab.com
Soil Testing for No Till Soil Testing for No Till FarmersFarmers I have been interested in developing I have been interested in developing
soil tests that could be analyzed soil tests that could be analyzed quickly and at low cost that could let quickly and at low cost that could let the farmer know how well his the farmer know how well his operation was improving yield and operation was improving yield and soil health.soil health.
Researchers at the National Tilth Lab Researchers at the National Tilth Lab at Ames Iowa are developing a soil at Ames Iowa are developing a soil quality index that may give the right quality index that may give the right parameters to analyze.parameters to analyze.
Soil Quality IndexSoil Quality Index
Total Organic CTotal Organic C Potential Potential
Mineralizable NMineralizable N Soil pHSoil pH Soil Extractable PSoil Extractable P Sodium Sodium
Adsorption RatioAdsorption Ratio Electrical Electrical
ConductivityConductivity
Microbial Microbial Biomass CBiomass C
Microbial Microbial Quotient qCOQuotient qCO22
Macroaggregate Macroaggregate StabilityStability
Available Water Available Water CapacityCapacity
Bulk DensityBulk Density
Carbon CycleCarbon Cycle
Total Organic CarbonTotal Organic Carbon
Soil Organic Matter testSoil Organic Matter test– Loss on Ignition (LOI)Loss on Ignition (LOI)
Carbon AnalyzerCarbon Analyzer Soil Organic Matter is 58 % CSoil Organic Matter is 58 % C Food for MicrobesFood for Microbes
Microbial BiomassMicrobial Biomass
Biological Activity Biological Activity Active Soil CarbonActive Soil Carbon Increases with Cropping IntensityIncreases with Cropping Intensity Measurement involves Incubation Measurement involves Incubation
for 3 days or morefor 3 days or more
Particulate Organic Particulate Organic MatterMatter Decomposed ResidueDecomposed Residue Slow Turnover Pool of OMSlow Turnover Pool of OM Soils with the Most Intensive Soils with the Most Intensive
Cropping System Contains the Cropping System Contains the Highest POMHighest POM
Major Substrate used by MicrobesMajor Substrate used by Microbes
Mineral Associated Mineral Associated Organic CarbonOrganic Carbon This Organic Carbon is Not This Organic Carbon is Not
Influenced by Cropping IntensityInfluenced by Cropping Intensity It is the Largest Supply of Organic It is the Largest Supply of Organic
CarbonCarbon Takes Years to IncreaseTakes Years to Increase Stabilized (that part we could not Stabilized (that part we could not
destroy by tillage)destroy by tillage)
Nitrogen CycleNitrogen Cycle
Nitrogen CycleNitrogen Cycle
Plant and Animal Residue/Organic Plant and Animal Residue/Organic Soil N/Air NSoil N/Air N
Microorganisms Microorganisms Ammonification (NH4) – Plant Ammonification (NH4) – Plant
Uptake – Soil ComplexUptake – Soil Complex Nitrification (NO3) – Plant Uptake – Nitrification (NO3) – Plant Uptake –
Leaching - DenitrificationLeaching - Denitrification Immobilization (Soil Organic N)Immobilization (Soil Organic N)
Sulfur CycleSulfur Cycle
Sulfur Cycle
Plant and Animal Residues/Organic Soil S Microbial Breakdown
– Oxidation/Reduction
Sulfates/Sulfides and from Fertilizers, etc Sulfate
– Plant uptake– Leaching– Soil Minerals
No-Till Sulfur No-Till Sulfur DeficiencyDeficiency Most of the Sulfur in the soil is Most of the Sulfur in the soil is
held in the organic matter portion held in the organic matter portion of the soilof the soil
The idea is to build organic matter The idea is to build organic matter to improve the health of the soil to improve the health of the soil and increase productivityand increase productivity
C : N : S ratioC : N : S ratio 100C : 8N : 1S100C : 8N : 1S
Soil Sample DepthSoil Sample Depth
Evaluating No-TillEvaluating No-Till– 0-2 inches most active0-2 inches most active– 2-6 inches 2-6 inches – 6-12 inches6-12 inches
Evaluating FertilityEvaluating Fertility– 0-8 inches for all nutrients0-8 inches for all nutrients– 8-36 inches for Nitrate, Chloride, 8-36 inches for Nitrate, Chloride,
Sulfate Sulfate
Nutrient Uptake and Nutrient Uptake and Root StructureRoot Structure
Granular StructureGranular Structure
Microbe TestsMicrobe Tests
Soil pHSoil pH
Important for Crop GrowthImportant for Crop Growth Important for Microbe GrowthImportant for Microbe Growth Tendency to Decrease over TimeTendency to Decrease over Time Some Herbicides Less Affective at Some Herbicides Less Affective at
Low pHLow pH Broadleaf Crops Contain more Broadleaf Crops Contain more
Calcium and Magnesium Calcium and Magnesium
Optimum Soil pHOptimum Soil pH
CropCrop Mid Point Mid Point Range (+/-)Range (+/-)
WheatWheat 6.36.3 .75 .75
CornCorn 6.36.3 2.0 2.0
SoybeanSoybean 6.36.3 1.2 1.2
SunflowerSunflower 6.66.6 2.1 2.1
Field PeasField Peas 6.56.5 1.0 1.0
Nitrate Soil TestNitrate Soil TestConsider nitrate in your root zoneConsider nitrate in your root zone
Total Lbs/A are availableTotal Lbs/A are available
Subtract total Lbs/A from N requirementSubtract total Lbs/A from N requirement
N recommendation based on nitrate in N recommendation based on nitrate in the root zonethe root zone
Phosphorus Soil TestPhosphorus Soil Test
Soil test ppm PSoil test ppm P Rating Rating % Sufficiency % Sufficiency
0-50-5 Very LowVery Low 25-5025-50
6-126-12 LowLow 45-8045-80
13-2513-25 MediumMedium 70-9570-95
26-5026-50 HighHigh 90-10090-100
51+51+ Very HighVery High 100 100
Phosphorus deficiencyPhosphorus deficiency
Potassium Soil TestPotassium Soil Test
Soil Test ppm K RatingSoil Test ppm K Rating% Sufficiency% Sufficiency
0-400-40 Very LowVery Low 20-5020-50
41-8041-80 LowLow 45-8045-80
81-12081-120 MediumMedium 70-9570-95
121-200121-200 HighHigh 90-10090-100
201+201+ Very HighVery High 100100
Sulfur Soil TestSulfur Soil Test
Soil Test ppm SSoil Test ppm S RatingRating
0-30-3 Very LowVery Low
4-64-6 LowLow
8-128-12MediumMedium
13-2013-20 HighHigh
20+20+ Very HighVery High
Sulfur in WheatSulfur in Wheat
Sulfur DeficiencySulfur Deficiency
Zinc Soil TestZinc Soil Test Soil Test ppm Zn Soil Test ppm Zn Rating Rating
0-.250-.25 Very LowVery Low
.26-.50.26-.50 LowLow
.51-1.00.51-1.00 MediumMedium
1.01+1.01+ HighHigh
Zinc Deficiency WheatZinc Deficiency Wheat
Zinc deficiencyZinc deficiency
Zinc Deficiency WheatZinc Deficiency Wheat
Copper Soil TestCopper Soil Test
0-.200-.20 LowLow .20-.60.20-.60 MediumMedium >.60>.60 HighHigh
Copper Deficiency Copper Deficiency WheatWheat
Copper Deficiency Copper Deficiency WheatWheat