Agriculture Reference
In-Depth Information
NRAW
Not readily available water
O
2
Oxygen
P
Phytochrome
P
Proportional (type of regulator)
PAR
Photosynthetically active radiation
PAR
abs
PAR absorbed by the crop
PAR
i
PAR incident on the crop
PAR
r
PAR reflected by the crop or albedo
PAR
t
PAR transmitted at soil level
PAR
t,r
PAR reflected from the soil level
PC
Polycarbonate
PE
Polyethylene
P
e
Effective rain
PET
Polyethylene terephthalate
P
FR
Phytochrome form
pH
Measure of the acidity of a solution
PMMA
Polymethyl methacrylate
PMMoV
Pepper mild mottle virus
Pn
Net productivity or net biomass gain or net photosynthesis
P
R
Phytochrome form
P
TOTAL
Total phytochrome
PVC
Polyvinyl chloride
PVF
Polyvinyl fluoride
PVY
Potato virus Y
P
w
Wind dynamic pressure
PWP
Permanent wilting point
Q
Heat exchanged per unit time
Q
c
Greenhouse heating requirements
q
c
Heat transmitted by conduction per unit time
q
conv
Heat transmitted by convection per unit time
Q
ren
Heat transmitted by air renewal per unit time
Q
s
Monthly heating consumption
R
Hourly greenhouse renewal rate (volumes per hour); also designates
respiration
R/FR
Red/far red ratio of radiation
R
a
Extraterrestrial radiation (or solar constant)
RAW
Readily available water
R
b
Gross irrigation water requirements
RGR
Relative growth rate
RH
Relative humidity (of air)
R
n
Net irrigation
R
s
Global solar radiation
RW
Reserve water
s
Second
S
Surface (m
2
); also designates south (cardinal point)
SAR
Sodium adsorption ratio
SAT
Associated growers organization
SBMV
Southern bean mosaic virus
S
c
Greenhouse cladding area
SLA
Specific leaf area
SLW
Specific leaf weight
