Vergara - 1976 - Physiological and morphological adaptability of ri

58 CLINLXTE AND RICE
Evaporation l mm/ét-‘l hrl
I5
IO
5
0
Max. temperuture (“Cl
5o
HHHH H HHHl l H H‘ H
45 — m"
40—
| 1 l 1 I
ll 2| 3| 8 l8 28 7 l?
l- July - l August +iSepembar ——
2o ' '
|
3. Rain)" days class A covered pan evaporation and maximum temperature dining klvarif
1972 at New Delhi (farm area. lARI).
maturity‘ period of the crop at the station, A week having a minimum of4 day's
each with at least 8 hours ofhright sunshine. equivalent to about 75 % ofpnssible
sunshine hours in a day. is used as an example.
Similarly. by extending the analysis over a network of rain gauge stations.
choosing a criterion of rainfall for defining consecutive wet days. the assured
rainfall periods for supplementary irrigation can be ascertained. at the threshold
Chance of occurrence (“M
I00
so -
6o _
bright sunshine
‘r-o’
o"
I
o
fuel.
4o
.
\ 0
\. 0 0
2o _ ~»"“'~v' e‘
f ‘¢"\ dry week
o
l l l l l l l I
4. Percent chance of occurrence of bright sunshine (continuous
line) and dry week (dashed line) during the crop
grohing period (July-October) at New Delhi (sec text for
dcfiniritin).