Crop Production

• Step 1: Calculate Total Hills per Hectare:

$$\text{Area} = 10,000\text{ m}^2, \quad \text{Spacing} = 0.20\text{ m} \times 0.20\text{ m} = 0.04\text{ m}^2$$ $$\text{Total Hills} = \frac{10,000}{0.04} = 250,000\text{ hills/ha}$$

• Step 2: Seedlings Required for Planting:

$$\text{Seedlings needed in main field} = 250,000 \times 2 = 500,000\text{ seedlings}$$

• Step 3: Account for 20% Uprooting Damage:

$$\text{Total seedlings required in nursery} = \frac{500,000}{1 - 0.20} = \frac{500,000}{0.80} = 625,000\text{ seedlings}$$

• Step 4: Account for Germination (90%) and Purity (90%):

$$\text{Real Value of Seed} = 0.90 \times 0.90 = 0.81$$ $$\text{Total seeds to be sown} = \frac{625,000}{0.81} \approx 771,605\text{ seeds}$$

• Step 5: Calculate Seed Rate using Test Weight (25 g per 1000 seeds):

$$\text{Seed Rate (kg/ha)} = \frac{771,605 \times 25\text{ g}}{1000 \times 1000} = 19.29\text{ kg/ha} \approx 19.3\text{ kg/ha}$$

• Conclusion: The required seed rate is 19.3 kg/ha. (Correct answer: Option 4)

• Bidi Tobacco (Nicotiana rustica and specialized N. tabacum cultivars): Synthesizes and accumulates the highest nicotine content (typically 5.0% to 8.0% or higher) due to low topping, close spacing, and specific alkaloid biosynthesis genetics.
• Chewing Tobacco: Contains moderate to high nicotine (3.0% to 4.5%).
• Cigar Tobacco: Contains moderate nicotine (1.5% to 3.0%).
• Cigar Wrapper Tobacco: Contains the lowest nicotine level (0.5% to 1.2%) to provide mild burning aroma without harshness. (Correct answer: Option 1)

• Montmorillonite / Smectite Group Minerals: Possess an expanding 2:1 layer crystal lattice consisting of two silica tetrahedral sheets sandwiching one alumina octahedral sheet.
• Specific Surface Area: Interlayer water and cations expand the interlayer spacing (up to 18 Å), exposing vast internal surfaces in addition to external surfaces, giving smectite/montmorillonite an immense total specific surface area of 600 to 800 $\text{m}^2/\text{g}$. Both Montmorillonite (Option 2) and Smectite (Option 3) represent this mineral group and were recognized as valid answers by NTA. (Correct answer: Options 2 & 3)
• Illite: Non-expanding 2:1 mineral fixed by interlayer potassium ($K^+$); surface area is 80 to 120 $\text{m}^2/\text{g}$.
• Kaolinite: 1:1 non-expanding mineral bonded by strong hydrogen bonds; specific surface area is only 10 to 30 $\text{m}^2/\text{g}$.

• Slurry Formation (A): Powdered rock phosphate (containing 30%–38% total $P_2O_5$) is reacted with sulfuric acid (65%–75% $H_2SO_4$) in an acidulator to produce soluble monocalcium phosphate and calcium sulfate.
• Denning Process (C): The reacting slurry is discharged into a den where solidification, continued acidulation, and initial crystallization of monocalcium phosphate occur over 0.5 to 4 hours.
• Curing (B): The solidified porous superphosphate mass is excavated and transferred to storage piles for 2 to 6 weeks of curing, allowing slow chemical reactions to reach equilibrium and excess free acid/moisture to dissipate.
• Granulation (D): If granular SSP is required, the cured or uncured powder can be granulated with water/steam in a rotary drum granulator.
• Conclusion: All operations (A), (B), (C), and (D) are integral components of single superphosphate manufacture. (Correct answer: Option 3)