Nutrient Management
Not publishedof exam
Plant NutritionSoil FertilityTestingSources4R StewardshipDiagnosticsPlanning
Soil and Water Management
Not publishedof exam
Soil PropertiesSite CharacterizationErosionTillageWater MovementIrrigationWater Quality
Pest Management
Not publishedof exam
IPMSamplingIdentificationThresholdsControlsStewardshipSafety
Crop Management
Not publishedof exam
Quick Facts
- Exam
- International CCA
- Format
- 150 multiple-choice
- Full-exam time
- 2.5 hours
- Modules
- 4
- Module weights
- Not published
- Pass score
- Not published
- Standard setting
- Modified Angoff
- Results
- Pass or fail
- Delivery
- Remote IBT; select in-person sites
- Exam windows
- 4 each year
- Section testing
- Route dependent
- Section time
- 1 hour when offered
- Completion window
- 5 years
- Remote scratch paper
- One blank sheet
- Remote calculator
- Built into exam
- Remote breaks
- None without accommodation
- Renewal
- 40 CEUs / 2 years
- Core CEUs
- 5 per core area
- Ethics CEU
- 1 per cycle starting 2026
The Four Rs
Source - Rate - Time - Place
Source: productRate: amountTime: uptakePlace: roots
Mineralization vs Immobilization
Mineralization
- Organic to inorganic
- Releases plant-available nutrients
- Microbial process
Immobilization
- Inorganic into biomass
- Temporarily reduces availability
- High-carbon residue risk
Release vs microbial tie-up
Field Diagnosis
- Problem first appears→Map the pattern(Edges, rows, patches)
- Pattern follows equipment→Check application(Rate and overlap)
- Symptoms follow drainage→Check roots and oxygen(Waterlogging possible)
- Older leaves affected→Check mobile nutrients(N, P, K, Mg)
- Newest leaves affected→Check immobile nutrients(Ca, B, Fe clues)
- Living agent suspected→Collect intact samples(Include transition zone)
- Nutrient issue suspected→Pair soil and tissue(Good versus poor)
- Cause is confirmed→Choose corrective action(Treat root cause)
Essential Plant Nutrients
- From air and water
- Carbon, hydrogen, oxygen
- Primary macronutrients
- Nitrogen, phosphorus, potassium
- Secondary macronutrients
- Calcium, magnesium, sulfur
- Micronutrients I
- B, Cl, Cu, Fe
- Micronutrients II
- Mn, Mo, Ni, Zn
- Essential total
- 17 elements
- Nitrogen
- Proteins and chlorophyll
- Phosphorus
- Energy transfer and roots
- Potassium
- Osmoregulation and enzymes
- Calcium
- Cell walls and membranes
- Magnesium
- Chlorophyll center
- Sulfur
- Sulfur amino acids
Soil vs Plant Mobility
Soil mobility
- Movement toward roots
- Controls leaching risk
- Nitrate highly mobile
Plant mobility
- Remobilization within plant
- Controls symptom location
- N symptoms start older
Transport in soil vs plant
Nutrient Plan Builder
- Starting recommendation→Define realistic yield(Crop and field)
- Need nutrient status→Use calibrated tests(Correct depth and method)
- Manure or legumes used→Subtract nutrient credits(Avoid double counting)
- Need product amount→Divide by grade fraction(N-P2O5-K2O basis)
- Loss risk is high→Split or stabilize(Match local guidance)
- Roots need access→Choose effective placement(Avoid seed injury)
- Recommendation complete→Check all four Rs(Source, rate, time, place)
- Application finishes→Document and evaluate(Improve next plan)
Nutrient Transformations
- Mineralization
- Organic to inorganic
- Immobilization
- Inorganic into biomass
- Nitrification
- Ammonium to nitrate
- Denitrification
- Nitrate to gases
- Volatilization
- Ammonia gas loss
- Leaching
- Solute below root zone
- Biological fixation
- Atmospheric N to ammonia
- Phosphorus fixation
- P becomes less soluble
- Crop removal
- Nutrients leave at harvest
- Residue return
- Nutrients cycle back
Soil Fertility Core
- CEC
- Holds exchangeable cations
- High CEC
- More nutrient buffering
- Base cations
- Calcium, magnesium, potassium, sodium
- Base saturation
- Base cations ÷ CEC
- Soil pH
- Hydrogen activity index
- Buffer pH
- Estimates lime requirement
- Low-pH toxicity
- Aluminum and manganese risk
- High-pH issue
- Many micronutrients become less available
- Organic matter
- Nutrients, aggregation, water holding
- Electrical conductivity
- Soluble salt indicator
Testing + Diagnostics
- Representative sample
- Many consistent subsamples
- Sampling depth
- Match calibration guidance
- Avoid odd areas
- Sample separately
- Grid sampling
- Systematic spatial pattern
- Zone sampling
- Management-based areas
- Plant analysis
- Confirms tissue nutrient status
- Paired sampling
- Good versus affected plants
- Mobile nutrient symptoms
- Older leaves first
- Immobile nutrient symptoms
- New growth first
- Visual diagnosis
- Hypothesis, not proof
- Field history
- Narrows likely causes
- Lab method
- Use locally calibrated interpretation
Deficiency Patterns
- Nitrogen
- Older uniform chlorosis
- Phosphorus
- Stunting, possible purpling
- Potassium
- Older marginal chlorosis
- Magnesium
- Older interveinal chlorosis
- Sulfur
- Newer uniform chlorosis
- Iron
- Newer interveinal chlorosis
- Zinc
- Short internodes, chlorosis
- Boron
- Growing-point injury
- Calcium
- Meristem and fruit disorders
- Symptom mimic
- Check roots and environment
4R + Fertilizer Math
- Right source
- Fits crop and site
- Right rate
- Matches need and credits
- Right time
- Synchronizes with uptake
- Right place
- Improves root access
- Fertilizer grade
- Percent N-P2O5-K2O
- Product needed
- Nutrient need ÷ decimal grade
- P2O5 to P
- Multiply by 0.44
- P to P2O5
- Multiply by 2.29
- K2O to K
- Multiply by 0.83
- K to K2O
- Multiply by 1.20
- Credits
- Manure, legumes, residual nutrients
- Plan records
- Source, rate, time, place
RUSLE Factors
A = R x K x LS x C x P
R: rainfallK: soilLS: slopeC: coverP: practice
Field Capacity vs Wilting
Field capacity
- After gravitational drainage
- Upper available-water boundary
- More water retained
Wilting point
- Plant cannot recover
- Lower available-water boundary
- Water held too tightly
Available water lies between
Water Management Picker
- Water ponds after rain→Check infiltration and drainage(Compaction or restriction)
- Runoff carries sediment→Add cover and slow flow(Contour and residue)
- Nitrate leaching risk→Match timing and uptake(Avoid excess water)
- Crop nears stress→Irrigate before depletion(Use rooting depth)
- Application is uneven→Check distribution uniformity(Nozzles and pressure)
- Salts accumulate→Assess EC and drainage(Leaching needs outlet)
- Sodium disperses soil→Assess SAR and calcium(Correct drainage first)
- Practice is selected→Monitor crop and water(Verify response)
Soil Physical Properties
- Sand
- 2.0 to 0.05 mm
- Silt
- 0.05 to 0.002 mm
- Clay
- Below 0.002 mm
- Texture
- Sand, silt, clay proportions
- Structure
- Arrangement into aggregates
- Bulk density
- Dry mass ÷ bulk volume
- Compaction
- Higher density, fewer pores
- Macropores
- Drainage and aeration
- Micropores
- Water retention
- Aggregate stability
- Resists slaking and erosion
- Tilth
- Suitability for crop growth
Leaching vs Runoff
Leaching
- Downward through profile
- Threatens groundwater
- Sandy soil risk
Runoff
- Across soil surface
- Threatens surface water
- Slope and sealing risk
Below root zone vs downslope
Soil-Water Relations
- Saturation
- Pores filled with water
- Field capacity
- After free drainage
- Permanent wilting point
- Plant cannot recover
- Available water
- Field capacity minus wilting
- Infiltration
- Water enters soil
- Percolation
- Water moves downward
- Capillary rise
- Water moves upward
- Evapotranspiration
- Evaporation plus transpiration
- Plant-available water
- Depends on texture and rooting
- Waterlogging
- Restricts root oxygen
- Restrictive layer
- Limits roots or drainage
Salinity vs Sodicity
Salinity
- High soluble salts
- Measured with EC
- Osmotic water stress
Sodicity
- High exchangeable sodium
- Assessed with ESP or SAR
- Dispersion and infiltration loss
Salt stress vs structure damage
Erosion + Tillage
- Sheet erosion
- Uniform thin-layer loss
- Rill erosion
- Small flow channels
- Gully erosion
- Channels tillage cannot erase
- Wind erosion
- Detachment and transport by wind
- RUSLE
- A = R K LS C P
- R
- Rainfall erosivity
- K
- Soil erodibility
- LS
- Slope length and steepness
- C
- Cover-management factor
- P
- Support-practice factor
- Residue cover
- Reduces detachment and runoff
- Contour farming
- Shortens downslope flow
Irrigation + Water Quality
- Irrigation need
- Crop use minus effective rainfall
- Application efficiency
- Stored water ÷ applied water
- Uniformity
- Evenness across field
- Overirrigation
- Leaching and runoff risk
- Underirrigation
- Yield-limiting stress
- Drainage
- Removes excess root-zone water
- Salinity
- Total soluble salts
- Sodicity
- Excess exchangeable sodium
- SAR
- Sodium hazard index
- High salinity
- Reduces water uptake
- High sodicity
- Disperses soil structure
- Nitrate risk
- Mobile groundwater contaminant
IPM PAMS
Prevent - Avoid - Monitor - Suppress
Prevent entryAvoid impactMonitor levelSuppress loss
Threshold vs Injury Level
Economic threshold
- Action point
- Below injury level
- Prevents economic loss
Economic injury level
- Loss equals control cost
- Damage benchmark
- Threshold must precede it
Act before loss equals cost
IPM Decision
- Injury is observed→Identify the cause(Biotic or abiotic)
- Pest is confirmed→Sample representative areas(Record crop stage)
- Population is below threshold→Monitor again(Do not treat automatically)
- Threshold is reached→Compare feasible tactics(Economic and environmental)
- Nonchemical control works→Prefer compatible tactic(Preserve natural enemies)
- Pesticide is justified→Read current label(Site, rate, timing)
- Resistance risk exists→Rotate effective groups(Not just brand names)
- Treatment is complete→Evaluate control(Document outcome)
IPM Foundations
- IPM
- Integrates compatible tactics
- Prevention
- Keep pest from establishing
- Avoidance
- Evade pest impact
- Monitoring
- Measure pest and crop
- Suppression
- Reduce unacceptable populations
- Economic injury level
- Loss equals control cost
- Economic threshold
- Act before injury level
- Tolerance
- Some pest presence accepted
- Natural enemies
- Predators, parasitoids, pathogens
- Best decision
- Economical and environmentally sound
Disease Triangle
Host + Pathogen + Environment
Susceptible hostVirulent pathogenFavorable environment
Biotic vs Abiotic Injury
Biotic
- Living causal agent
- May spread over time
- Signs may be present
Abiotic
- Nonliving causal factor
- Often follows field pattern
- No pathogen signs
Organism vs environment
Sampling + Identification
- First diagnostic step
- Identify accurately
- Representative pattern
- Cover field variability
- Sampling unit
- Plant, row, area, trap
- Sampling frequency
- Match pest development
- Random sampling
- Each unit has equal chance
- Systematic sampling
- Regular field intervals
- Degree-days
- Predict development timing
- Disease triangle
- Host, pathogen, environment
- Abiotic injury
- Nonliving causal factor
- Biotic injury
- Living causal agent
- Field pattern
- Clue, not final diagnosis
Pest Control Tactics
- Cultural
- Rotation, planting date, sanitation
- Mechanical
- Cultivation, traps, barriers
- Biological
- Natural enemies or biopesticides
- Genetic
- Resistant crop traits
- Regulatory
- Quarantine and exclusion
- Chemical
- Pesticide when justified
- Mode of action
- Biochemical target process
- Resistance selection
- Repeated pressure favors survivors
- Rotate groups
- Change modes, not brands
- Tank mixture
- Each partner must be effective
- Refuge
- Maintains susceptible individuals
Pesticide Stewardship
- Label
- Legal use directions
- Signal word
- Acute toxicity category
- PPE
- Follow label minimums
- REI
- Restricted-entry interval
- PHI
- Application-to-harvest interval
- Drift
- Off-target airborne movement
- Runoff
- Surface transport with water
- Volatility
- Vapor movement after application
- Sensitive area
- Protect with label controls
- Spill priority
- Protect, control, contain
- Records
- Document product and application
Four Exam Modules
Nutrients - Soil/Water - Pests - Crops
No published weightsStudy every POPass via Modified Angoff
Fixed vs Variable Cost
Fixed cost
- Exists without production
- Depreciation and ownership
- Allocated across output
Variable cost
- Changes with production
- Seed, fertilizer, fuel
- Relevant to marginal choice
Ownership vs operating cost
Stand Decision
- Emergence is uneven→Count multiple locations(Map weak zones)
- Plants are missing→Inspect seed and roots(Find causal evidence)
- Stand is below target→Estimate surviving yield(Use local response data)
- Replant is possible→Estimate delayed yield(Later maturity risk)
- Comparing choices→Add replant costs(Seed, fuel, herbicide)
- Existing stand competes→Include termination cost(Check label restrictions)
- Net return favors replant→Select adapted maturity(Protect season length)
- Decision is made→Record assumptions(Review after harvest)
Cropping Systems
- Rotation
- Sequences crops across seasons
- Monoculture
- Same crop repeatedly
- Intercropping
- Crops grown together
- Double cropping
- Two harvests one season
- Cover crop
- Protects and improves soil
- Legume credit
- Reduces later nitrogen need
- Reduced tillage
- Preserves residue cover
- Crop diversity
- Breaks pest cycles
- System tradeoff
- Yield, risk, soil, profit
- Rotation restriction
- Check pesticide carryover
US/Canada Exam Pair
International
- General agronomic knowledge
- 150 questions
- Two and one-half hours
Local Board
- Regional agronomy
- 100 questions
- Two hours
US/Canada: general plus regional
Selection + Establishment
- Maturity
- Fits frost-free season
- Yield stability
- Performance across environments
- Resistance traits
- Match local pest pressure
- Seed quality
- Germination, vigor, purity
- PLS percentage
- Purity × germination ÷ 100
- Planting depth
- Moisture plus emergence balance
- Seedbed
- Firm, moist, well-aerated
- Plant population
- Live plants per area
- Emergence percentage
- Plants emerged ÷ seeds planted
- Stand assessment
- Count, uniformity, plant health
- Replant decision
- Expected gain versus delay
Full Exam vs Section Testing
Full exam
- All four modules together
- One testing session
- ICCA allows 2.5 hours
Section testing
- Each module registered separately
- One hour per section
- Finish sections within five years
Starting sections commits to sections
Growth + Diagnostics
- Photosynthesis
- Builds carbohydrate using light
- Respiration
- Releases stored energy
- Transpiration
- Water loss through stomata
- Vegetative stage
- Leaves, stems, roots
- Reproductive stage
- Flowers, seed, fruit
- Critical period
- Stress most reduces yield
- Growing degree-days
- Heat accumulation above base
- GDD daily
- Mean temperature minus base
- Source
- Exports assimilates
- Sink
- Uses or stores assimilates
- Root cause
- Confirm before treatment
Technology, Harvest + Economics
- GPS
- Satellite position
- GIS
- Spatial data analysis
- Remote sensing
- Measures without contact
- Yield monitor
- Maps harvest response
- Variable-rate application
- Changes rate by location
- Ground truthing
- Verifies sensed patterns
- Harvest timing
- Balance yield, quality, losses
- Safe storage
- Manage moisture and temperature
- Aeration
- Controls grain temperature
- Fixed cost
- Does not vary with output
- Variable cost
- Changes with production
- Break-even yield
- Total cost ÷ price
- Break-even price
- Total cost ÷ yield
- Partial budget
- Compares changed costs and returns
Exam + Credential Rules
- International full exam
- 150 questions, 2.5 hours
- Local Board full exam
- 100 questions, 2 hours
- US and Canada route
- International plus Local Board
- Mid-Atlantic route
- Additional nutrient exam applies
- Outside US/Canada/Mexico
- Separate preapproval route
- Full-exam route
- All modules in one sitting
- Section route
- Register each module separately
- Section-eligible exams
- US/Canada ICCA and Local Board
- Section testing
- One hour per section
- Section order
- Any order
- Section commitment
- Finish that exam by sections
- Section deadline
- Five years after first section pass
- Section proctoring
- Separate sessions add proctor fees
- Outside-US/Canada/Mexico sections
- Not offered
- Completion clock
- Five years after first pass
- Application timing
- Within six months after both passes
- Bachelor's route
- Two years qualifying experience
- Associate route
- Three years qualifying experience
- No-degree route
- Four years qualifying experience
- Experience incomplete
- CCA Candidate status available
- CEU cycle
- 40 every two years
- Each core area
- At least five CEUs
- Board-approved CEUs
- At least 20 per cycle
- Professional ethics
- Starting 2026, at least one
- Outside-route CEUs
- At least 20 through online classroom
- Annual renewal
- Pay required fee
Remote Test Day
- Standard delivery
- Remote-proctored internet-based testing
- In-person exception
- Select regions and dates
- Computer
- Windows or Mac desktop/laptop
- Not supported
- Tablet, Chromebook, smartphone
- Displays
- One computer monitor only
- Cameras
- Computer plus second camera
- Identification
- Valid government photo ID
- Name rule
- Must match registration exactly
- Workspace
- Quiet, clean, materials removed
- Allowed paper
- One blank sheet
- Writing tool
- Pen or pencil
- Calculator
- Provided within exam
- Breaks
- Only with approved accommodation
- Wearables
- No watches, headphones, hats
- Browser
- Chrome, Firefox, or Edge
- Before closing
- Show and destroy scratch paper
Common Traps
Invented domain weights
ASA publishes four modules ≠ It does not publish weights
Assuming a 70% pass
No universal percent published ≠ Modified Angoff sets standard
Exam equals certification
Exams are one requirement ≠ Experience and references remain
International exam only
US and Canada need local exam ≠ Mid-Atlantic may need another
Assuming sections are universal
Availability depends on route ≠ Outside-US/Canada/Mexico route excluded
Brand rotation
Brand change may keep mode ≠ Rotate effective MOA groups
Threshold equals injury
Threshold triggers action ≠ Injury level equals economic loss
Mobility confusion
Soil mobility predicts transport ≠ Plant mobility predicts symptoms
Grade reports elemental P
Fertilizer label uses P2O5 ≠ Potassium is reported as K2O
Symptoms prove deficiency
Many stresses mimic nutrients ≠ Confirm with evidence
More irrigation always helps
Excess drives runoff and leaching ≠ Schedule to root-zone need
Remote exam means open book
Workspace must be cleared ≠ Only allowed materials stay
Immediate result is final email
Screen shows pass or fail ≠ Official email follows later
Last Minute
- 1.150 questions in 2.5 hours
- 2.Four modules; weights unpublished
- 3.Modified Angoff; no fixed percent
- 4.Remote: one blank scratch sheet
- 5.Use the built-in calculator
- 6.No routine remote-exam breaks
- 7.Match ID name exactly
- 8.Know all current Performance Objectives
- 9.Memorize the 17 essential nutrients
- 10.Separate soil and plant mobility
- 11.Use source-rate-time-place
- 12.Subtract nutrient credits
- 13.Grade means N-P2O5-K2O
- 14.Available water = FC minus PWP
- 15.RUSLE = R K LS C P
- 16.Threshold comes before injury level
- 17.Identify before treating
- 18.Rotate mode-of-action groups
- 19.Confirm field symptoms with evidence
- 20.Compare marginal costs and returns
- 21.International plus applicable local exam
- 22.Pass required exams within five years
- 23.Sections depend on candidate route
- 24.Renew with 40 CEUs per cycle
- 25.Earn five CEUs in each core
- 26.Include one professional-ethics CEU
- 27.Ensure 20 CEUs are Board-approved
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