92 



THE DATE PALM. 



The surface crust showed the following composition: 



TABLE 26. Per cent of alkali soluble in excess of water in surface crust, from. Station No. 1, 



Ourlana, Algeria. 1 



Calcium sulphate 3. 21 



Magnesium sulphate 2. 67 



Magnesium chlorid 71 



Sodium chlorid i 7. 52 



Potassium chlorid 29 



Sodium bicarbonate .12 



Total . . 1 4. 52 



The soil to a depth of 4 feet showed the following amounts of alkali: 

 TABLE 27. Per cent of alkali in soil of date orchard, Station No. 1, at Ourlana, Algeria. 1 



Seidell's original analyses of the samples from this station are as follows: 



The fourth foot from the surface, where the subsoil was full of water, shows a 

 larger amount of alkali than does the third foot. This amount of alkali w T as evi- 

 dently without effect on the date palm. 



Station No. 2 at Ourlana (PI. XVII, fig. 1) was of much interest, because located 

 between old and flourishing date palms which had been planted ten years or more. 

 Notwithstanding the existence of a drainage ditch only a few feet away and of the 

 fact that the irrigation water had been applied to the whole surface of the soil by 

 flooding, the surface still showed a considerable crust of alkali. Water was 

 encountered at a depth of 30 inches, which was below the level of the shallow 

 drainage ditch. 



