moisture probes
Instruments used to determine soil moisture levels at
various depths.
nonpoint source pollution
Water contamination from diffuse sources such as agricultural
fields, urban runoff, or large construction sites.
off-target site
Any area, plant, or organism inadvertently receiving
pesticide spray, drift or residue.
point source pollution
Sources of pollution that have easily identified points
of entry into a body of water.
rapidly-bound pesticide
A pest control chemical that is tied-up in the soil due
to its chemical charge.
resistance blocks
Electrical resistance block systems that use small gypsum
blocks and a portable resistance meter to measure soil moisture content.
When the blocks are placed in contact with the soil, the moisture content
of the gypsum block tends to equal the moisture content of the soil. Measurement
of electrical resistance by a meter is a good indication of the soil moisture
content. The drier the soil, the greater the electrical resistance.
riparian areas
Lands adjacent to creeks, streams and rivers where
vegetation is strongly influenced by the presence of
water.
runoff
Irrigation water that runs off the end of a graded field.
short-lived pesticide
A pesticide that persists only a short time in the environment
(usually less than a 21 day half-life). |
soil water depletion/ soil moisture depletion/soil
water deficit
Terms commonly used for the amount of water used
below field capacity. The depletion or deficit at any time is the amount
of water needed to refill the current crop root zone to field capacity.
side dressing
In-season application of fertilizers, usually applied
at lay-by.
surge irrigation system
An irrigation system where the water is cycled between
two sets to wet the entire length of the field. Each cycle is progressively
longer so the water travels a similar distance with each advance. After
completion of advance, the shorter on-time provides soak cycles to fill
the root zone.
tail water
Irrigation water runoff from a graded field.
tail water recovery systems
A structure that collects tailwater runoff on-farm and
returns it to the distribution system for reuse.
tensiometer
A sealed, water-filled tube equipped with a vacuum gauge
on the upper end and a porous ceramic tip on the lower end. As roots remove
water from the soil, soil moisture tension increases. Water moves out through
the ceramic tip, creating a partial vacuum which registers on the vacuum
gauge.
tillage
Soil inversion or shattering by various mechanical implements.
wetlands
Areas characterized by soils that are usually saturated
or ponded, i.e., hydric soils, that support mostly waterloving plants (hydrophytic
plants). |
