Environmental Engineering Reference
In-Depth Information
Herbicide, non-selective:
A herbicide that kills all plant tissues that it
touches.
Herbicide, post-emergent:
A herbicide that is applied to control weeds
after their germination and emergence from the soil.
Herbicide, pre-emergent:
A herbicide that is applied to turf to control
germinating weed seeds.
Herbicide, selective:
A herbicide that affects only a specific weed or
group of weeds and has minimal effects on desirable plants.
Hybrid:
The offspring of parents from different species or varieties.
Hydrophobic:
Tending to repel water.
Infiltration:
The downward entry of water into the soil.
Insecticide:
A pesticide used to control insects.
Irrigation system:
A system for delivery of supplementary water to
plants, often a network of underground pipes and pop-up sprinklers
controlled by manual or automatic valves.
LD
50
:
The dosage of a toxic substance that kills half of the test organ-
isms in an acute study.
Loam:
A type of soil composed of moderate amounts of sand, silt and
clay.
Macronutrients:
The nine nutrients required by plants in large quan-
tities: nitrogen, phosphorus, potassium, calcium, magnesium, sulphur,
carbon, hydrogen and oxygen.
Macropores:
Large pores in soils that drain freely by gravity.
Micronutrients:
The seven nutrients required by plants in small quan-
tities: manganese, iron, boron, zinc, copper, molybdenum and chlorine.
Micropores:
Small soil pores that retain water by capillary action and
do not drain freely by gravity.
Monostand:
An area of turf-grass made up of one species of plant.
Mower, flail:
A mower with pivoting blades or flails that spin horizon-
tally at high speed around a vertical axis.
Mower, reel:
A mower that shears the grass between a blade on a
spinning cylinder and a bed knife at the base of the cutting unit.
Mower, rotary:
A mower that cuts by the impact of a horizontal spin-
ning blade.
