38 



AGRICULTURAL EXPLORATIONS IN ALGERIA. 



probable that many waters that ha\e heretofore been condemned as 

 too saline could safely be used in irrigating crops. 



The date palm is the most salt-resistant cultivated plant of the Sahai'a, 

 so far as is known. The maxjnuim amount of salt in the irrigating 

 water which this tree can endure without detriment to the crop has not 

 been ascertained. It would appear, howev^er, to be something less than 

 1,000 parts per 100,000, for water of a pond containing 1,044: parts per 

 100,000 of soluble salts, of which 1,036 parts was sodium chlorid, 

 had been found to be too salty for irrigating a young date orchard. 



A number of samples of artesian water used in irrigating the oases 

 near Tongourt, in the Oued Rirh region, were taken by the writers 

 and were analyzed in the laboratory of the Bureau of Soils of the 

 Department of Agriculture. The results are stated in the following 

 table: 



Table 6. — fhemlt-al miahisett of nrtes^ian irater used in irrigating gardens in Snliarnn oases, 



Algeria. 



Coiistiluent. 



Ions: 



Calcium (Ca) 



Magnesium ( Mg) 



Sodium (Na) 



Potassium ( K ) 



Sulpiiuric acid (SO4) 



Chlorin (CI) 



Bicarbonic acid ( HCO:i) 



Conventional combinations: 



Calcium sulphate (CaS04) 



Magnesium sulphate (MgSO^).. 



Magnesium chlorid ( MgCl2) 



Potassium chlorid (KCl) .'. 



Sodium bicarbonate (NaHCOa) . 



Sodium chlorid (NaCl) 



Total solids in 100,000 parts water . 



601.50 



408. 10 



571.90 



These are fair average samples of the irrigation waters in use, and 

 do not represent b}' any means the maximum of salinity. Field tests 

 showed as high as 816 parts to 10<y,000 in water in actual use on soils 

 where garden vegetables were growing, while French authorities report 

 the use of waters carrying 812 parts per 100,000. 



SOILS. 



The soils of Algeria are of many varieties and t3'pes, varying from 

 the coarsest sands to heavy clays. The differences are due chicHy t > 

 two causes — the nature of the underlying I'ocks and the climatic c> n 

 ditions under which the soil was formed. Ditferent cla.sses of soils m ■ 

 found in each ph^^siographic region and there are few types wh.ica 

 are common to all three regions. In the littoral zone of the coast 

 region much of the soil is of the adobe type, containing a considerable 

 (juantity of claj'. In the alluvial bottoms, however, we rind extensive 

 areas of other kinds of soil. In the mountain zone the soils are not 



