SNR (Soil Nutrient Requirement) in STCR equation refers to:

Correct option is A

· In STCR (Soil Test Crop Response), SNR = Soil Nutrient Requirement, also called NR.
· Defined as: “Amount of nutrient required to produce 1 unit (q/ha) of yield.”
Why other options are wrong
· (b) Total fertilizer is computed later, not SNR.
· (c) Not related to organic matter.
· (d) Residual effects handled separately, not SNR.