GROWTH AND WATER USE OF VEGETABLES 



247 



mm /day 



5 



• 1957 

 o 1958 

 + 1959 

 X 1960 



"►o^X -fc 



■J^ 



"nT'sn 



7 8 



mm / day 



Fig. la. Relation between pan-evaporation in mm per day and measured incoming 

 radiation (i?^) in cal cm-^ per day. Average values of lo-day periods. 



tainer was filled with a layer of gravel (5 cm), coarse sand (5 cm) and 50 to 

 60 cm of a light clay-loam or sandy soil. 



During the experimental period, various data on temperature, relative 

 humidity and pan-evaporation were measured. The daily radiation was 



mm /day 

 5 



• 1957 

 o 1958 

 + 1959 

 X1960 





o it 



^-+ 



4^X X X ° 



L^. 



100 



200 



300 



400 



500 



600 - 7 00 



cal in cm /day 



Fig. lb. As Fig. la, but Rm'^''^ i^rri and multiplied by (A/ A + y) (where A is the 

 slope of temperature-maximal vapour pressure curve and y is the psychrometer 

 constant). 



17 



