Differences between Differential Pressure Deficit (DPD) and Water Potential!
Differential Pressure Deficit (DPD):
1. It is an old term that was coined by Meyer (1938). It is equivalent to water potential.
2. It has positive value, e.g., 5 atm.
3. DPD is the reduction in diffusion pressure of solvent in a system over its pure state.
4. Water is absorbed by a system having higher DPD from another system with lower DPD.
5. DPD = OP – TP where all terms are with positive value.
6. Matrix pressure or imbibition force is not considered.
1. Coined by Slatyer and Taylor (1960) and is equivalent to DPD.
2. It has negative value, e.g., – 5 atm.
3. It is reduction in free energy of solvent in a system over its pure state.
4. Water is absorbed by a system with lower water potential from another system with higher water potential.
5. Ψw = Ψs + Ψp where Ψs has a negative value while Ψp has a positive value.
6. Matrix potential or Ψm is considered wherever it is appreciable.