100+ Free CAIS Practice Questions

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Question 1

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Which soil texture has the highest water-holding capacity per unit depth?

Sandy loam

Clay

Loamy sand

Coarse sand

to track

2026 Statistics

Key Facts: CAIS Exam

100

Exam Questions

Irrigation Association

3 hrs

Time Limit

Irrigation Association

$200

Member Exam Fee

Irrigation Association

20 CEUs

Recertification (2 yr)

Irrigation Association

60-100 hrs

Recommended Study

Estimated

8 domains

Content Areas

IA Candidate Handbook

The CAIS (Certified Agricultural Irrigation Specialist) is the Irrigation Association's professional credential for on-farm irrigation management. The 3-hour, 100-question exam tests mastery of ET-based scheduling, soil-water relationships, surface and pressurized irrigation systems, fertigation/chemigation, salinity management (leaching fraction, SAR), and distribution uniformity. Field experience and intermediate math skills — including pump curves, ETc calculations, and unit conversions — are essential for success.

Sample CAIS Practice Questions

Try these sample questions to test your CAIS exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Which soil texture has the highest water-holding capacity per unit depth?

A.Sandy loam

B.Clay

C.Loamy sand

D.Coarse sand

Explanation: Clay soils have the finest particle size and greatest surface area, giving them the highest water-holding capacity — often 1.5 to 2.5 inches of plant-available water per foot. The tradeoff is slower infiltration and drainage. Sandy soils hold far less water but drain and accept water quickly.

2What does the term 'field capacity' (FC) describe in soil science?

A.The soil moisture level at which plants begin to wilt permanently

B.The maximum amount of water a soil can hold against gravity after drainage has ceased

C.The volumetric water content of a completely saturated soil

D.The average moisture content of a soil profile under continuous irrigation

Explanation: Field capacity is the soil moisture content remaining after gravitational drainage has essentially stopped, typically 1–2 days after saturation. It represents the upper end of plant-available water and is the target refill point for most irrigation scheduling methods. At field capacity, large pores are air-filled and small pores hold water.

3A soil has a field capacity of 28% and a permanent wilting point of 12% (both volumetric). What is the total available water (TAW) in the top 2 feet of the root zone?

A.3.84 inches

B.6.72 inches

C.7.68 inches

D.4.32 inches

Explanation: TAW = (FC − PWP) × root zone depth = (0.28 − 0.12) × 24 inches = 0.16 × 24 = 3.84 inches. This is the maximum plant-available water stored in the top 2 feet. Irrigation scheduling typically replenishes only the management-allowed depletion fraction (MAD) of TAW, not the full amount.

4Which irrigation system type is generally most appropriate for undulating or hilly terrain where surface runoff is a concern?

A.Furrow irrigation

B.Border strip flooding

C.Drip (micro) irrigation

D.Wild flooding

Explanation: Drip (micro) irrigation delivers water directly to the root zone at low pressure and flow rates, making it well-suited for uneven terrain where gravity-flow systems would cause erosion, runoff, or uneven distribution. Emitter placement is independent of slope. Surface systems require careful land leveling and grade management.

5A center-pivot irrigator applies 0.8 inches of water per pass. If crop ET is 0.25 in/day and the pivot takes 3 days to complete one revolution, how much net water is applied per revolution relative to crop demand?

A.The pivot applies 0.05 inches more than crop demand

B.The pivot applies 0.75 inches less than crop demand

C.The pivot applies exactly the crop demand

D.The pivot applies 0.05 inches less than crop demand

Explanation: Crop demand per revolution = 0.25 in/day × 3 days = 0.75 inches. Application = 0.80 inches. Net difference = 0.80 − 0.75 = +0.05 inches excess. This slight over-application builds a small soil-water buffer. Scheduling should be adjusted seasonally as ET changes with crop growth stage and weather.

6Which of the following best defines evapotranspiration (ET)?

A.Water lost from the soil surface only, measured by lysimeter

B.The combined loss of water by evaporation from the soil surface and transpiration from plant leaves

C.The total rainfall minus infiltration and runoff losses

D.The net soil water depletion measured by neutron probe over 24 hours

Explanation: ET combines two water-loss pathways: evaporation from the soil surface and transpiration through plant stomata. ET is the primary driver of crop water demand and forms the basis for all science-based irrigation scheduling methods including the water-balance approach. Reference ET (ETo) is calculated from weather variables using equations like Penman-Monteith.

7The FAO Penman-Monteith equation is the standard method for calculating which parameter?

A.Crop coefficient (Kc)

B.Reference evapotranspiration (ETo)

C.Soil evaporation coefficient (Ke)

D.Actual crop ET adjusted for stress (ETa)

Explanation: The FAO-56 Penman-Monteith equation calculates reference ET (ETo) — the ET of a hypothetical short grass reference crop under well-watered conditions. Inputs include solar radiation, air temperature, humidity, and wind speed. Actual crop ET is then calculated as ETc = Kc × ETo, where Kc is the crop coefficient for a given growth stage.

8A corn crop has a mid-season Kc of 1.15 and ETo is 0.28 inches/day. What is the estimated crop ET (ETc) for a 7-day period?

A.1.96 inches

B.2.25 inches

C.2.52 inches

D.1.64 inches

Explanation: ETc = Kc × ETo = 1.15 × 0.28 in/day = 0.322 in/day. Over 7 days: 0.322 × 7 = 2.254 inches ≈ 2.25 inches. During the mid-season growth stage, Kc peaks above 1.0 for many field crops because they transpire more water per unit area than the reference grass under the same conditions.

9In furrow irrigation, what is the primary purpose of tailwater recovery?

A.To measure soil infiltration rate at the furrow end

B.To capture runoff from the lower end of the field and recycle it for reuse

C.To reduce the furrow inflow rate and prevent soil erosion at the field head

D.To flush excess fertilizer from the field before it reaches drainage ditches

Explanation: Tailwater recovery systems collect the runoff (tailwater) that exits the lower end of furrow-irrigated fields and return it to the irrigation supply, often pumping it to a storage pond or back to the field head. This improves overall irrigation efficiency, reduces water waste, and prevents nutrient-laden runoff from reaching waterways.

10The management-allowed depletion (MAD) for a stress-sensitive vegetable crop is typically set at what percentage of total available water (TAW)?

A.50–60%

B.70–80%

C.30–40%

D.10–20%

Explanation: Stress-sensitive crops such as vegetables and fruit trees are commonly managed at a MAD of 30–40% of TAW to avoid any yield-reducing water stress. Field crops like corn may use 50–60% MAD. The lower the MAD, the more frequent irrigations are needed, but plant stress and yield loss are minimized.

About the CAIS Exam

Professional certification for agricultural irrigation specialists. The CAIS exam covers soils, evapotranspiration, irrigation systems, scheduling, salinity, drainage, and efficiency across 100 questions in 3 hours.

Questions

100 scored questions

Time Limit

3 hours

Passing Score

Scaled (not disclosed)

Exam Fee

$200 (member) / $450 (non-member) (Irrigation Association)

CAIS Exam Content Outline

~12%

Soils

Texture, water-holding capacity, field capacity, wilting point, bulk density, hydraulic conductivity

~15%

Evapotranspiration

Penman-Monteith ETo, crop coefficients (Kc), ETc calculation, FAO-56 dual Kc

~25%

System Types

Surface, sprinkler (pivot, hand-move), microirrigation, fertigation/chemigation equipment

~20%

Irrigation Scheduling

Water-budget, soil moisture sensors, ET-based scheduling, MAD, crop stress stages

~12%

Salinity

ECw, ECe, SAR, leaching fraction, osmotic stress, salt tolerance thresholds

~8%

Drainage

Surface and subsurface drainage, drainage coefficient, Hooghoudt equation, deep percolation

~8%

Efficiency & Distribution Uniformity

DU, CU, application efficiency, pump curves, TDH, BEP, NPSHa, LEPA

How to Pass the CAIS Exam

What You Need to Know

Passing score: Scaled (not disclosed)
Exam length: 100 questions
Time limit: 3 hours
Exam fee: $200 (member) / $450 (non-member)

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

CAIS Study Tips from Top Performers

1Download and memorize the IA CAIS equation sheet — every calculation on the exam uses these formulas

2Master ETc = Kc × ETo and leaching fraction calculations — these appear on nearly every IA ag exam

3Know the difference between matric potential (tensiometer, gypsum block) vs. volumetric water content (capacitance probe, neutron probe)

4Learn the NRCS practice standards: 430 (scheduling), 441 (microirrigation), 443 (sprinkler), 442 (surface)

5Review salt tolerance ECe thresholds for 6-8 common crops — barley (8), cotton (7.7), alfalfa (2.0), corn (1.7), beans (1.0)

Frequently Asked Questions

How many questions are on the CAIS exam?

The CAIS exam has 100 equally weighted multiple-choice questions. You have 3 hours to complete it. The Irrigation Association provides an equation sheet during the exam.

What is the CAIS passing score?

The Irrigation Association does not publish the exact passing score for the CAIS. It uses a scaled scoring approach. Candidates should target strong competency across all content areas — soils, ET, system types, scheduling, salinity, drainage, and efficiency.

What math is on the CAIS exam?

Expect to calculate ETc (= Kc × ETo), leaching fraction (LF = ECw / (5×ECe − ECw)), system capacity (Q = A×d×18.86/t in gpm), distribution uniformity, and interpret pump curves. An equation sheet is provided. Practice these formulas until they feel automatic.

How do I prepare for the CAIS exam?

Focus on the eight exam content areas from the IA Candidate Handbook: soils, ET, system types, scheduling, salinity, drainage, efficiency, and regulations. Study the IA equation sheet and practice calculations. Complete 100+ practice questions. Field experience with drip, pivot, and surface systems significantly helps with applied knowledge questions.

What are the CAIS recertification requirements?

CAIS holders must earn 20 CEUs per 2-year cycle to maintain certification. Annual renewal costs $75 (IA member) or $125 (non-member) for a single certification.