10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
These 10 free CAIS questions are organized by exam domain, so you can see how each part of the Certified Agricultural Irrigation Specialist blueprint is tested. Reveal the answer and explanation under each question.
Domain 1: Soil-Plant-Water Relationships 15% of exam
Question 1
Published rooting depths suggest 1.2 m for a mature corn crop. In this block, soil pits show roots turning sideways at a compacted horizon 0.45 m below ground, with no active roots beneath it. The subsoil is moist, but monitoring detects no upward water contribution. When estimating plant available water capacity for the current irrigation schedule, the specialist should use:
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Correct answer: B - The available-water capacity of the root-accessible 0.45 m profile.
Question 2
Soil pits in an irrigated bed show a wet silt loam layer directly over loose, largely dry coarse sand. There is no compacted or cemented layer, and the water table is well below the profile. A contractor expected the coarse layer to improve drainage. What explains water accumulating above this interface?
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Correct answer: C - The coarse layer initially has low unsaturated conductivity, delaying entry from the finer soil.
Domain 2: Irrigation Methods 10% of exam
Question 3
A furrow-irrigated field consistently has deep percolation near the inlet and inadequate wetting near the tail. The grade is uniform, the soil does not change along the run, and the current stream is well below the largest nonerosive flow the furrows can carry. Field length cannot be changed this season. Which operating change best addresses the head-to-tail imbalance?
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Correct answer: A - Increase the advance flow, then cut back after water reaches the tail.
Domain 3: Basic Hydraulics 5% of exam
Question 4
Weak discharge is reported from the uphill end of a drip lateral. A technician records 28 psi at the supply hydrant with the lateral's inlet valve closed and concludes that pressure is adequate. The emitters' rated pressure-compensating range is 12-35 psi. Which measurement would best test that conclusion?
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Correct answer: B - Pressure at the last emitter while the normal combination of zones is operating.
Domain 4: Efficiency and Uniformity 14% of exam
Question 5
In a fixed-grid sprinkler test, 12 equal-area collectors record 6, 7, 8, 9, 9, 10, 10, 11, 12, 12, 13, and 13 mm. The overall mean of 10 mm meets the planned average depth, but the low catches coincide with dry strips. The evaluation uses low-quarter distribution uniformity (DU), based on the mean of the lowest 25% of catches rather than the single minimum. Which report conclusion is supported?
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Correct answer: A - DU is 70%; correct the distribution problem rather than lengthen every set.
Domain 5: Irrigation Scheduling 20% of exam
Question 6
A vegetable block begins the day at field capacity. Grass-reference evapotranspiration for the day is 6.0 mm, and the crop coefficient for its current growth stage and the same reference is 1.20. Rain supplies 1.2 mm of effective root-zone water. The drip system applies 2.0 mm/hour gross over the block, of which 75% is retained in the root zone. No leaching is required. Neglect evapotranspiration during the refill. What runtime replaces the day's net depletion?
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Correct answer: C - 4.0 hours
Question 7
A corn block's effective root zone has a plant available water capacity of 100 mm. The farm permits 40% depletion during flowering. The last sector reached by its center pivot has a current depletion of 18 mm. Forecast crop evapotranspiration is 6 mm/day, with no effective rain or capillary contribution. Once the pivot starts, water will not reach that sector for 48 hours. Which listed start time is the latest that avoids exceeding the depletion limit before water arrives?
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Correct answer: B - Start in 24 hours.
Domain 6: Water Quality, Salinity and Drainage 8% of exam
Question 8
A clay-loam field changes irrigation-water supplies. Electrical conductivity (EC) falls from 1.6 to 0.30 dS/m, but the sodium adsorption ratio remains 8.0. Within several irrigations, surface sealing and runoff increase at the same application rate. No new machinery traffic or sediment load is identified. How should the two water-quality measurements be interpreted?
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Correct answer: D - The lower EC can increase clay dispersion at this sodium adsorption ratio, reducing infiltration.
Domain 8: Chemigation 8% of exam
Question 9
While a pesticide authorized for chemigation is being applied through a center pivot, the irrigation pump trips and mainline flow falls to zero. The injector continues cycling, and pesticide is still being drawn from the tank. The mainline check valve is intact. What is the operator's immediate priority?
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Correct answer: D - Stop the injector and shut off withdrawal from the pesticide tank.
Domain 9: Irrigation Management 15% of exam
Question 10
During a routine check, a drip block's flow is below its established baseline. Pump discharge pressure is unchanged, the pressure drop across the filter has risen from 2 to 10 psi even at the lower flow, and lateral-inlet pressure is low. Both gauges have been checked, and valve positions are unchanged. Where should troubleshooting start?
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Correct answer: C - Service the filter and verify its backwashing cycle.