soil water

cohesion

attraction of water molecules to each other

adhesion

attraction of water molecudes to soils surfaces

soil water potential

energy requirements to move water from the soil to the reference state of water = 0

how is water potential defineed

energy is produced as water moves to free water potential

matric potential

force by which soil particles attract and hold water molecules (combined effect of cohesion and adhesion)

capillarity

attractive force which lifts water above free water surface against the force of gravity

what determines the height of capillary water rise

diameter

rate of capillary water movement is also a function of soil pore size

important for water movement to plant roots

osmotic potential

attraction of water molecules to cations or anions in the soil

how would addition of fertalizer to a soil affect the osmotic potential

more

how owuld drying a soil affect the osmotic potential

more

total water potential

sum of matric, osmotic, pressure and gravitational potenial

maximum rententive capacity

all pores are filled with water

field capacity

matric potenital holds some waterk

knowing the field capacity tells us

max water that is useful for plants

hygroscopic coeffcient

all the pores are empty and the only water is immediately around the soil particles

variable of amount of water available

soil texture

field capacity of water

depends on texture

plant available water increases with OM describe graph