Agriculture Reference
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D T max (°C)
June
20
September
March
10
December
0
35 N
40 N
Latitude (°)
45 N
Fig. 4.2. example of the maximum amplitude of the temperature increase ( D T max) in a closed
greenhouse, well irrigated, at different times of the year and at different latitudes (adapted from Nisen
et al ., 1988).
Table 4.1. Values of maximum global solar radiation intensity (W m −2 ) predictable as a function of
latitude, at noon (northern hemisphere). (Source: Nisen et al ., 1988.)
Latitude
December
March
June
September
32°N
550
915
1050
855
38°N
455
845
1025
780
44°N
355
770
995
685
T = 2.5°C
100
T = 5°C
50
T = 10°C
0
R s
kcal m -2 h -1
300
350
600
900
W m -2
700
1.050
Fig. 4.3. estimation of the hourly air exchange rate R in a well-irrigated greenhouse, to maintain ambient
warming to a given air temperature ( D T ) value with respect to the outside air as a function of solar
radiation ( R s ) (adapted from Nisen et al ., 1988).
increase of the average temperatures of
around 5°C.
In view of these predictions, the
thermal climate limits for protected culti-
vation, without active climate control
equipment, would be between 12 and 22°C
of average temperatures in coastal areas
and 12-17°C in inland areas. Outside these
limits, protected cultivation would require
active climatization systems: heating and
mechanical ventilation or misting for
cooling.
 
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