Soil Water and Water Quality

- utilization - removal of excess water - distribution of water

The Midwest, water problems are primarily related to:

coarse

What would drain faster, fine or coarse textured soils?

positive

a flooded soil puts a (positive/negative) pressure or potential on the water in the soil

tightly

as soil gets drier, it is held more (loosely/tightly) and thus is harder to pull away from the soil matrix.

ceased

at field capacity, water has _______ to flow out of the soil

loosely

at saturation, water is held (tightly/loosely).

zero

at the boundary between an unsaturated and saturated soil, the pressure or potential is _______

used all the water they can

at wilting point, plants have _______________________

adhesion

dominant force holding water to the soil surface

% water by volume = (volume water in soil/volume of soil) *100

equation for calculating % water by known volume

% H2O by weight = (wt water in soil/wt soil oven dried) * 100

equation for calculating % water by weight

% water by volume (unknown) = % H2O weight * Bulk density

equation for calculating % water for unknown volume

- water content & potential on horizons - soil strength & density - soil depth - root depth - soil layerin

factors affecting the amount of plant-available soil water

capillary rise

flow due to negative potential created by adhesion and cohesion

hydrogen bonding

hydrogen of one water bonding to the oxygen of another water

mulches

keep soil wet and reduces temperature fluctuations

fallow

kept free of plants, keeps more water in soil

double ring infiltrometer

minimizes lateral spreading, ensures downward vertical flow

% H2O FC - % H2O WP = % available H2O

plant available water equation

gravity

pressure disappears after water is drained away under the force of ________.

- leaching calcium - damages structures - speed up acidification of lakes & streams

problems of acid rain include:

transpiration

productive evaporation; builds biomass of plants through photosynthesis

acidic

rainfall water is naturally (acidic/basic)

irrigation

should be done on sandy/shallow soils

adds nutrients back into soil

sulfur and nitrogen from acid rain can be beneficial because:

gravitational flow

synonym for saturated flow

capillary flow

synonym for unsaturated flow

osmotic potential

the force with which an aqueous solution attracts water by osmosis

- matric potential - osmotic potential

the negative potential in soil is provided by these 2 sources:

silt > clay > sand

the order in which we expect to have the most capillary rise over an extended period of time

matric potential

the potential energy generated by the attractive forces between water molecules and soil particles

tension

the same as negative pressure or potential

prescription athletic turf

type of athletic grass that used moisture sensors to indicate root/plant needs and uses heating coils to prevent freezing in the ground water; uses suction pumps to get rid of excess water and has drains & subirrigation present

cohesion

water clinging to water

polar

water is a ______ molecule

both

water molecules are attracted to (negatively/positively/both) charged surfaces

-0.3 bars

water potential at field capacity

-15 bars

water potential at wilting point

- gravimetric - neutron scattering - resistance blocks - time domain reflectometry (TDR) - Tensiometer - watermark monitoring

what are 6 ways of measuring soil moisture?

- reduces frost heaving - reduces risk of damaging soil - increases oxygen in root zone - reduces heat capacity, helps growth

what are some advantages of draining excess water from a field?

- open ditches - tile drains - table control

what are three different drainage systems?

water pressure

what controls the rate of saturated flow?

allows soil to hold onto water

what does adhesion and cohesion allow soil to do with water?

- method of sewage & waste water treatment - reverse soil drainage

what is the purpose of a septic system?

- layers of fragipan - gleying - steep slopes - excessive drainage

what soil properties limit on-site disposal systems?

silt loam, clay loam, clay

which textures can hold the most available water?

concrete & pavements seal off soil so soil can't take in water

why does water move more rapidly in urban environments?

macropores

(micropores/macropores) drain faster under gravity

horizontal

In which orientation does the screen and sponges hold the most water (from demo)?