Chapter 6 & 7 Flashcards
Available water
Water, readily absorbed by plant roots. The amount of water released between the field capacity and the permanent wilting point.
(o Water available for plants use.
o Water in the soil between field
capacity and the wilting point.
o Expressed as: AW = FC-WP
o Water between field capacity and
saturation is not available to the
plants because it is lost through
drainage (pulled out by gravity).
JTF Introduction to Agriculture 74
o Plants vary in abilities to extract water from the soil near WP.
-This is not the same for all species of plants.
o Varies with the soil as well, because some soils are more charged than others (electrically), such as clay; water is held more tightly by the cation―anion bond.
- Water in the soil which exists at a microscopic level as a layer around particles of clay.)
Border irrigation
used where the land is level
Check
areas bounded by levees [an embankment] running down slope
Distribution system
Canals, ditches, pumps and pipelines that deliver water to an individual farm.
( Often this type of irrigation project is built
by the government.
Payment for construction and
maintenance is sometimes prorated to the
landowners.)
Drip irrigation
A method of irrigation that conserves water by slowly releasing small amounts of water through emitters near the plant.
Emitters
A device which regulates the amount of water released; found in drip or trickle irrigation systems
Field capacity
Amount of water a soil can hold against gravity; expressed as a percentage of the dry weight of a soil.
Flood irrigation
On level land, water enters through a head ditch or biplane and is released into the individual checks (areas bounded by levees running downslope) by siphons, gates, or valves.
Furrow irrigation
Water runs down the furrows between plant rows. Water moves to all parts of the soil by capillary action or gravity.
Gate
Door or valve controlling water passage.
Hygroscopic water
Water held by electrical attraction and is unable to leave the soil.
Levee
Earthen dike used to enclose water.
Permanent Wilting Point (PWP)
When soil becomes too dry for the plant to access any water. Plants will not recover even if conditions improve.
Saturation
When all of the pore (voids) spaces in the soil are full of water.
Scientific Irrigation System (SIS)
Helps irrigators know exactly when and how much to irrigate crops through a system that monitors weather and soil moisture data.
Siphon
Tube used to convey liquid upwards.
Solvent
A liquid capable of dissolving. Water is the universal solvent.
Turgor
Stiffness in the cells.
Water holding capacity
Ability of a soil to retain (hold) water.
Wilting Point (WP)
Water between field capacity and saturation is not available to the plants because it is lost through drainage (pulled out by gravity).
