RPSC Agriculture Research Officer (Agriculture Chemistry) - 2024

In USDA Soil Taxonomy, the Soil Moisture Control Section for coarse sandy soils is between 30 and 90 cm.

• 90 to 120 cm: Deep horizon depth exceeding standard soil classification moisture control sections.
• 10 to 30 cm: Standard SMCS limits for clayey and fine loamy textural classes.
• 20 to 60 cm: Standard SMCS limits for coarse loamy textural classes.
• 30 to 90 cm: Due to high macroporosity and low water retention, the wetting front penetrates deeper in sandy soils, establishing the control section at 30 to 90 cm.

A mass spectrometer separates ionized isotopic species based on their mass-to-charge ratio (m/z).

• Electric charge: Isotopic ions usually carry identical net electrical charges (e.g., +1), making pure charge differentiation impossible.
• Atomic number to charge ratio: Isotopes of an element share identical atomic numbers (Z), preventing separation by this metric.
• Decay constant: Pertains to radioactive half-life and rate of spontaneous nuclear disintegration, not electromagnetic deflection.
• Atomic mass to charge ratio: Accelerated ions entering a magnetic field follow curved trajectories whose radii depend strictly on their mass-to-charge ratio (m/z).

Mahua cake contains toxic saponins (mowrin) that retard microbial nitrification, resulting in very slow, prolonged nutrient release ideal for orchards and long-duration crops.

• Cottonseed cake: Mineralizes rapidly within 10 to 15 days, best suited for short-duration seasonal crops.
• Groundnut cake: Quick-acting organic manure whose nitrogen mineralizes within 7 to 10 days.
• Castor cake: Mineralizes relatively fast and is commonly used for annual field crops.
• Mahua cake: Decomposes and releases nitrogen very slowly (taking up to 2 months or more) due to mowrin content, providing steady sustained feeding for orchard trees.