I - Lag phase II - log phase or exponential phase (Growth)  III - Stationary phase IV - Death phase

The range at which soil essential elements concentration is recorded for optimal plant growth is during the log phase, which is a phase of rapid growth in plants:

• Log phase: This is the phase of rapid growth in plants.
• Lag phase: This is the initial phase of growth when the rate of growth is very slow.
• Stationary phase: This is the phase when the rate of growth starts decreasing and finally stops

Stationary / steady phase is where finally growth stops.

The range at which soil essential elements concentration is recorded for optimal plant growth is marked II.