Soil-Water-Plant Relationships

• Drying Kinetics and Equipment in Agricultural Processing:
• Statement (I): Majority of the drying of agricultural produce fall under falling rate regime. $\implies$ Correct.
• Cereal grains, pulses, and oilseeds dry almost entirely in the falling-rate drying period, where internal moisture diffusion governs drying rate rather than surface evaporation.
• Statement (II): Spray dryers are commonly used for liquid foods. $\implies$ Correct.
• Spray drying atomizes liquid feeds (milk, coffee, fruit purees) into a hot gas stream to produce dry powders in seconds.
• Conclusion: Both Statement (I) and Statement (II) are correct (Option 1).

Correct option: (1) Both Statement (I) and Statement (I) are correct

• Centrifugal Pumps in Series Operation:
• Pumps in Series: The discharge outlet of the first pump is piped directly into the suction inlet of the second pump.
• Discharge ($Q$): The mass flow rate passes sequentially through both pumps; hence total discharge remains equal to that of a single pump ($Q_{\text{total}} = Q_1 = Q_2$).
• Total Head ($H$): Each pump imparts its individual pressure head to the flowing liquid; thus heads add algebraically ($H_{\text{total}} = H_1 + H_2$).
• Pumps in Parallel: Discharge doubles while head remains constant.
• Conclusion: Only delivery head increases (Option 3).

Correct option: (3) only delivery head increases

• Design Frequencies for Soil Conservation Structures:
• Earth dams having natural spillways $\to$ (II) 25 - 50 years: Built for permanent gully control and flood prevention where failure could cause moderate damage.
• Stock water dams $\to$ (I) 25 years: Designed to retain runoff for livestock drinking water with emergency spillways rated for 25-year storms.
• Terrace outlets and vegetated waterways $\to$ (IV) 10 years: Standard grassed waterways and terrace channels are designed for a 10-year recurrence interval storm without scouring.
• Field diversions $\to$ (III) 15 years: Diversion ridges/ditches carrying runoff away from gullies or fields use a 15-year design frequency.
• Matching Result: (A) - (II), (B) - (I), (C) - (IV), (D) - (III) (Option 4).

Correct option: (4) (A) - (II), (B) - (1), (C) - (V), (D) - (tll)

• Kirpich Equation for Watershed Time of Concentration:
• In hydrology, the Kirpich (1940) equation expresses the time of concentration ($T_c$) in minutes for small agricultural watersheds:

where:

• $L$ is the maximum length of flow along the main channel (meters)
• $S$ is the dimensionless average slope of the watershed channel ($H / L$)
• Conclusion: 0.0195 L^0.77 S^-0.385 (Option 1).

Correct option: (1) 0.0195 L^{0.77} S^{-0.385}