Correct Answer - Option 4 : capillary potential
Concept:
Capillary potential:
It is also known as soil matric potential. Capillary potential can be defined as, The force per unit area that must be exerted in order to extract water from the soil. Capillary forces are the main force moving water in the soil and it typically will move water into smaller pores and into the drier regions of soil. Water potential is highly texture-dependent. Clay particles have a larger surface area and thus will have a higher affinity for water than that of silt or sandy soils. Tensiometer is used for the measurement of capillary potential.
Soil moisture deficiency:
The water required to bring the soil moisture content of a given soil to its field capacity Is called the field moisture deficiency or soil moisture deficiency. The infiltrated water first meets the soil moisture deficiency if any and excess water moves vertically downwards to reach the groundwater table.
Moisture equivalent:
It is defined as the water content expressed as a percentage of the dry weight that a soil can retain against a centrifugal force one thousand times the force of gravity and used as a convenient laboratory measure of soil moisture conditions.
