Japan Professional Engineer (技術士) First-stage Exam — Agriculture division · Japan · Institution of Professional Engineers, Japan (IPEJ)
Original practice questions written to the published syllabus · not past papersEnough agronomy to design for the crop: sowing geometry for planters, application rates for sprayers, moisture at harvest.
In the exams: Allied agricultural sciences in PRC ABE; core in the ICAR 6th Deans' Committee B.Tech
How our questions for Japan Professional Engineer First-stage Exam spread across the units of Crop Production & Protection for Engineers. Difficulty: 8 easy, 17 medium, 5 hard.
| Pest and disease management and application rates | 18 | |
| Weed management | 12 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
A herbicide applied after sowing but before the crop and weeds emerge is described as:
C. Pre-emergence
Pre-emergence herbicides are applied to the soil surface after sowing and before emergence. Post-emergence products go on emerged weeds; pre-plant incorporated products are mixed into soil before sowing; a directed spray is a post-emergence spray aimed below the crop canopy.
Further reading: Zimdahl, Fundamentals of Weed Science
A farmer irrigates a prepared field, lets the first flush of weeds emerge, kills them with a shallow pass or a non-selective herbicide, and then sows. This practice is called:
C. A stale seedbed
The stale seedbed technique depletes the surface weed seed bank before sowing. Solarisation heats moist soil under clear plastic; smother cropping uses a competitive crop to suppress weeds; allelopathic mulching relies on chemicals released by residue.
Further reading: Zimdahl, Fundamentals of Weed Science
A fungicide is recommended at 0.75 kg a.i./ha. The product contains 500 g a.i. per litre and the sprayer applies 300 L/ha from a 400 L tank. How much product goes into each full tank?
C. 2.0 L
Product per ha = 0.75 ÷ 0.5 = 1.5 L. One tank covers 400 ÷ 300 = 1.333 ha, so product per tank = 1.5 × 1.333 = 2.0 L. 1.5 L is the per-hectare amount; 1.1 L scales by 300/400 instead of 400/300; 1.0 L treats the 0.75 kg a.i. dose as if it were litres of product (0.75 × 1.333).
Further reading: Matthews, Pesticide Application Methods
The 'disease triangle' states that a plant disease develops only when three things coincide. They are:
C. A susceptible host, a virulent pathogen and a favourable environment
Disease needs host, pathogen and environment together; removing any one prevents it. Vectors matter only for some diseases; fungicides are control measures; nitrogen and sowing date can modify disease but are not the triangle.
Further reading: Plant pathology texts
A sprayer calibrated at 6 km/h delivers 150 L/ha. The operator drives at 8 km/h without changing nozzles or pressure. What is the actual application rate, and what happens to the dose of a.i. if the tank mix was made for 150 L/ha?
D. 112.5 L/ha, and the a.i. dose falls by 25 %
Rate ∝ 1/speed at constant flow: 150 × 6 ÷ 8 = 112.5 L/ha. The tank concentration is fixed, so a.i. per hectare also falls to 75 % of target. 200 L/ha inverts the speed ratio; a fixed-pressure sprayer without rate control does not compensate; and with a fixed concentration, a.i. dose falls in step with volume.
Further reading: Matthews, Pesticide Application Methods
Which practice is a cultural method of pest management rather than a chemical or biological one?
B. Adjusting the sowing date so the susceptible crop stage avoids peak pest flight
Changing sowing date is a cultural method. Trichogramma releases and NPV sprays are biological controls; seed treatment with an insecticide is chemical control.
Further reading: IPM texts
A knapsack sprayer operator walks at 3.6 km/h spraying a 1.0 m swath and the nozzle delivers 0.6 L/min. What volume is applied per hectare?
D. 100 L/ha
Rate = 600 × 0.6 ÷ (3.6 × 1.0) = 100 L/ha. 10 L/ha is a factor-of-ten slip; 216 multiplies flow by speed instead of dividing (0.6 × 3.6 × 100); 167 puts the 1.0 m swath in place of the 0.6 L/min flow (600 × 1.0 ÷ 3.6).
Further reading: Matthews, Pesticide Application Methods
Which group of weeds is generally hardest to control with grass herbicides used in rice and wheat?
B. Sedges such as Cyperus species
Sedges differ botanically from grasses (triangular stems, often tubers) and are not controlled by most grass-specific herbicides. Echinochloa, Phalaris minor and wild oats are grasses targeted by those products.
Further reading: Zimdahl, Fundamentals of Weed Science
The pre-harvest interval on a pesticide label is:
B. The minimum time between the last application and harvest of the crop
The PHI ensures residues fall below the maximum residue limit by harvest. Equipment cleaning, pre-plant soil timing and shelf life are separate label items.
Further reading: WHO / Codex Alimentarius
A pest density of 8 larvae per plant causes damage worth exactly the cost of spraying. Field scouting shows 5 larvae per plant and rising. Which statement is consistent with IPM?
D. 8 per plant is the EIL; spraying is justified once counts reach the lower ETL, set to act before 8 is reached
The density at which damage equals control cost is the economic injury level. The economic threshold is set below it so that control acts before the EIL is reached; with counts rising, action at the ETL is justified. Waiting beyond 8 lets damage become uneconomic; IPM does not aim for zero; and 5 is below the EIL by definition.
Further reading: IPM texts
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