Finals Unit 2 Flashcards
What is the process of determining when to irrigate and how much water to apply based on measurements or estimates of soil moisture or water used by plants.
Irrigation Scheduling
a measure of the adsorptive forces by which soil retains water. It is the negative pressure (suction) relative to the prevailing atmospheric gauge pressure of zero.
Tension
The unit commonly used in irrigation scheduling to express soil-water tension.
Bar
A condition where the soil pores are filled with water.
Saturation
At saturation, how much is soil-water tension?
Zero
The soil-water content after the force of gravity has drained or removed all the water.
Field Capacity
It is considered as the upper limit of plant-available water.
Field Capacity
Water in the soil that is free to drain or move by the force of gravity.
Gravitational water
It is the volume of water in the soil between saturation and field capacity
Gravitational Water
This water is not usually used by plants.
Gravitational water
Water retained in soil pores after gravitational water has drained or that is held loosely around soil particles by surface tension.
Capillary water
Most of the water available to plants
Capillary Water
The soil-water content at which the healthy plants can no longer extract water fast enough to recover from wilting.
Permanent Wilting Point
The lower limit of plant-available water.
Permanent Wilting Point
Soil-water tension of 15 bars.
Permanent Wilting Point
The amount of water held in soil available to plants. The difference between FC and PWP.
Plant Available Water
Water in thin, tightly held films around soil particles not available to plants.
Unavailable water
The amount of plant-available water removed from the soil by plants and evaporation from the soil surface.
Depletion Volume
The amount of plant-available water can be removed from the soil without seriously affecting plant growth and development.
Allowable Depletion Volume
This method determines soil moisture by taking a sample from the desired soil depth, weighing it to be oven-dried. The dried sample is then re-weighed to determine amount of water lost.
Gravimetric Method
A sealed, airtight, water-filled tube with a pourous tip on one end and a vacuum gauge.
Tensiometer
This tool isnuesd to measure soil water suction, usually expressed as tension.
Tensiometer
This measurement tool consist of two electrodes enclosed in a block of pourous material.
Electrical Resistance Block
The electrical block is often made of:
Gypsum
It is a device used for measuring the rate of water uptake of a leafy shoot.
Photometer
What is the other term for photometer?
Transpirometer
A symptom shown when plants lose their turgidity usually at midday.
Temporary Wilting
Soils taken from root zone depth
Feel the Soil
