14 GEOGRAPHICAL DISTRIBUTION 



The Reh Commission brought out the fact that under 

 the ancient systems of agriculture in India there was very 

 little increase in the amount of soluble salts at the surface, 

 but with the construction of large modern canals and the 

 application of unnecessarily large quantities of irrigation 

 water the increase in alkali was very rapid. 



Leather (12) has pointed out that not all the lands called 

 by the natives "usar " owe their infertility to alkali. Some 

 simply have very hard clay soils which are difficult to 

 bring into a good state of tilth. The true "reh" lands, 

 however, are like the alkali lands of other parts of the 

 world. 



Australia. The greater part of Australia may be con- 

 sidered as arid although the rainfall of the eastern part of 

 the continent is high. During the last generation large 

 irrigation works have been constructed and vast tracts of 

 land containing a rather high content of soluble salts have 

 been brought under cultivation. In such sections alkali 

 is one of the serious problems. Alkali conditions in Aus- 

 tralia are somewhat similar to those of the western part of 

 the United States. 



REFERENCES 



1. AMES, J. W. Some Alkali Soils in Ohio. Ohio Sta. Mo. Bui. i (1916), 



No. 7, pp. 209-210. 



2. ATTI, R. A Saline Soil of the Lower Valley of the Po (Italy). Accad. 



Econ. Agr. Firenze, 5, Ser. 3 (1906), No. i, pp. 59-64. (Abs. E. S. 

 R. 18, p. 215.) 



3. BANCROFT, R. L. The Alkali Soils of Iowa. Iowa Sta. Bui. 177 



(1918), pp. 185, 208. 



4. BURD, J. S. Alkali Conditions in the Payette Valley. Idaho Sta. 



Bui. 51 (1905), pp. 1-20. 



5. CLARKE, F. W. The Data of Geochemistry. U. S. Geol. Survey, 



Bui. 616 (1916), pp. 143-167 and 206-247. 



6. DEAKIN, ALFRED. Irrigated India, 322 pp. (London, 1893.) 



