LEA Mock Test: Computation Based Questions with Answers

1. A rice crop has a nitrogen recommendation of 120 kg N ha⁻¹. If urea (46% N) is the only N source used, how many kilograms of urea per hectare should be applied? (Use: kg fertilizer = N requirement / fraction N in fertilizer)

• a) 208 kg ha⁻¹
• b) 261 kg ha⁻¹
• c) 320 kg ha⁻¹
• d) 180 kg ha⁻¹

2. Maize is to be planted at 0.75 m between rows and 0.20 m between plants in a row. Desired plant population is one plant per hill; seed germination is 85% and 1000-seed weight is 300 g. Approximately what seed rate (kg ha⁻¹) should be sown? (Steps: plants ha⁻¹ = 10,000 / (row spacing × plant spacing); seeds to sow = plants / germination; kg = (seeds/1000) × (1000-seed weight g)/1000)

• a) 30.6 kg ha⁻¹
• b) 23.5 kg ha⁻¹
• c) 18.9 kg ha⁻¹
• d) 45.0 kg ha⁻¹

3. A soil core of volume 1000 cm³ yielded an oven-dry mass of 1200 g. What is the bulk density of the soil? (Bulk density = dry mass / volume)

• a) 0.83 g cm⁻³
• b) 1.00 g cm⁻³
• c) 1.20 g cm⁻³
• d) 1.50 g cm⁻³

4. Convert grain moisture content from 25% (wet basis) to dry basis. (Use: M_dry = M_wet / (1 − M_wet), where M expressed as decimal)

• a) 20.0% (dry basis)
• b) 25.0% (dry basis)
• c) 30.0% (dry basis)
• d) 33.33% (dry basis)

5. A pig grows from 20 kg to 50 kg body weight while consuming 100 kg of feed. What is the feed conversion ratio (FCR)? (FCR = feed consumed / weight gain)

• a) 3.33
• b) 2.50
• c) 4.00
• d) 1.25

6. A crop requires 5 mm evapotranspiration per day. If irrigation is withheld for 10 days, what volume of water (m³) is required to replace ET over 1 ha? (1 mm on 1 ha = 10 m³)

• a) 50 m³
• b) 5000 m³
• c) 500 m³
• d) 250 m³

7. In a selection trial phenotypic variance (Vp) = 25 and genotypic variance (Vg) = 10. What is the broad-sense heritability (H²) expressed as a percentage? (H² = Vg / Vp × 100)

• a) 25%
• b) 40%
• c) 60%
• d) 16%

8. A farmer has fixed costs of ₹20,000 and variable costs of ₹15,000 for a crop whose expected yield is 4 tonnes per hectare. What is the break-even price (₹ per tonne)? (Break-even price = (fixed + variable)/yield)

• a) ₹7,500 per tonne
• b) ₹8,250 per tonne
• c) ₹9,000 per tonne
• d) ₹8,750 per tonne

9. You have a 20% (w/v) stock solution of a pesticide and need to prepare 10 L of 0.1% (w/v) spray. How many millilitres of the stock are required? (Use C1V1 = C2V2)

• a) 50 mL
• b) 5 mL
• c) 500 mL
• d) 250 mL

10. An irrigation requirement for a field is 50 mm (depth) on a 1-ha plot. If the pump must supply this water in 2 hours, what is the required pump discharge in L s⁻¹? (1 ha × 50 mm = 500 m³; 1 m³ = 1000 L)

• a) 69.44 L s⁻¹
• b) 120.00 L s⁻¹
• c) 30.56 L s⁻¹
• d) 250.00 L s⁻¹

11. A dairy cow consumes 25 kg of dry matter daily and gains 1.5 kg body weight per day. What is its feed efficiency? (Feed efficiency = weight gain / feed intake)

• a) 0.06
• b) 0.15
• c) 1.67
• d) 0.25

12. If 1 kg of complete fertilizer (14-14-14) costs ₱25, what is the cost per kilogram of nitrogen supplied? (Use: 1 kg fertilizer contains 0.14 kg N)

• a) ₱150.00 per kg N
• b) ₱178.57 per kg N
• c) ₱125.00 per kg N
• d) ₱200.00 per kg N

13. A hybrid corn field has an average yield of 8 tons ha⁻¹. If the moisture at harvest is 25% and the market requires 14% moisture, what is the adjusted yield at 14% moisture? (Adjusted yield = (100 − harvest moisture)/(100 − required moisture) × actual yield)

• a) 7.6 tons ha⁻¹
• b) 7.9 tons ha⁻¹
• c) 8.4 tons ha⁻¹
• d) 9.1 tons ha⁻¹

14. A 15% protein concentrate and a 5% protein roughage are mixed to produce 100 kg of feed with 10% crude protein. What amount of concentrate is needed? (Use: Pearson’s square method)

• a) 25 kg
• b) 33.3 kg
• c) 50 kg
• d) 66.7 kg

15. If a hybrid’s mean yield is 80 q ha⁻¹, the population mean is 60 q ha⁻¹, and the selection differential is 20 q ha⁻¹, with heritability 50%, what is the expected genetic gain? (Genetic gain = h² × selection differential)

• a) 5 q ha⁻¹
• b) 8 q ha⁻¹
• c) 10 q ha⁻¹
• d) 20 q ha⁻¹

16. A soil sample weighing 500 g is dried and loses 50 g of water. What is its moisture content on a wet basis? (Moisture % = water loss / wet weight × 100)

• a) 5%
• b) 8%
• c) 10%
• d) 12%

17. The productivity index (PI) of a cropping system is calculated as PI = (Yield of crop / Standard yield) × 100. If maize yields 6 t ha⁻¹ and the standard yield is 8 t ha⁻¹, what is PI?

• a) 60%
• b) 70%
• c) 75%
• d) 80%

18. If the discount rate is 10% per year, what is the present value (PV) of ₱1,000 received after two years? (PV = FV / (1 + r)ⁿ)

• a) ₱826.45
• b) ₱900.00
• c) ₱950.00
• d) ₱1,100.00

19. The area under a rectangular farm is 1.5 ha with a length of 300 m. What is its width? (1 ha = 10,000 m²)

• a) 40 m
• b) 45 m
• c) 50 m
• d) 60 m

20. A soil has 25% porosity and a total volume of 1 m³. How much air space (in liters) is present in that soil? (1 m³ = 1000 L)

• a) 150 L
• b) 200 L
• c) 250 L
• d) 300 L

21. Sunflower is planted at 0.70 m between rows and 0.30 m between plants. If desired is one plant per hill and seed germination is 90% with 1000-seed weight = 50 g, approximately what seed rate (kg ha⁻¹) should be sown?

• a) 1.75 kg ha⁻¹
• b) 2.65 kg ha⁻¹
• c) 5.28 kg ha⁻¹
• d) 10.00 kg ha⁻¹

22. Farmyard manure (FYM) contains 0.6% nitrogen (N). If a farmer applies 5 t ha⁻¹ FYM, how many kg of N ha⁻¹ are supplied?

• a) 6 kg N ha⁻¹
• b) 15 kg N ha⁻¹
• c) 30 kg N ha⁻¹
• d) 300 kg N ha⁻¹

23. A 500 kg batch of grain at 20% moisture is dried to 12% moisture (dry matter constant). Approximately how many kilograms of weight are lost during drying?

• a) 25.0 kg
• b) 40.0 kg
• c) 100.0 kg
• d) 45.45 kg

24. A broiler consumed 4.5 kg of feed and gained 2.2 kg live weight. What is the feed conversion ratio (FCR)? (FCR = feed consumed / weight gain)

• a) 2.05
• b) 1.67
• c) 3.00
• d) 0.49

25. How many kilograms of P₂O₅ are contained in a 250 kg bag of fertilizer labeled 16-20-0 (N–P₂O₅–K₂O)?

• a) 16.0 kg P₂O₅
• b) 50.0 kg P₂O₅
• c) 32.0 kg P₂O₅
• d) 250.0 kg P₂O₅

26. A rectangular farm has an area of 36,000 m². What is this area in hectares?

• a) 2.6 ha
• b) 3.0 ha
• c) 3.6 ha
• d) 36.0 ha

27. In a breeding trial, additive genetic variance (Va) = 6 and phenotypic variance (Vp) = 20. What is the narrow-sense heritability (h²) in percent?

• a) 10%
• b) 20%
• c) 50%
• d) 30%

28. A pump delivers 0.05 m³ s⁻¹ of water to a lift (head) of 20 m. Calculate the hydraulic power in kW (use ρ = 1000 kg m⁻³ and g = 9.81 m s⁻²). (Power = ρ g Q H)

• a) 9.81 kW
• b) 1.96 kW
• c) 0.981 kW
• d) 98.1 kW

29. If 1 g of a soluble fertilizer is dissolved in 2 L of water, what is the concentration in ppm (mg L⁻¹)?

• a) 200 ppm
• b) 500 ppm
• c) 1000 ppm
• d) 50 ppm

30. Given particle density = 2.65 g cm⁻³ and porosity = 40%, what is the bulk density (g cm⁻³) of the soil? (Bulk density = particle density × (1 − porosity))

• a) 0.40 g cm⁻³
• b) 1.00 g cm⁻³
• c) 1.59 g cm⁻³
• d) 2.65 g cm⁻³