ALKALI LANDS 211 



The surface soil was now rich in nitrates, while the chlorides 

 occupied a lower level. We find in consequence that the 

 nitrates diminished greatly in the drainage water as the 

 running from the pipe began to lessen, while the chlorides 

 largely increased. The composition of three successive col- 

 lections of the drainage water was in parts per million as 

 follows : 



Nitrogen as Nitrates. Chlorine. 



November 15, 4 p.m. ... 67-8 39.0 



16,8a.m. ... 50-0 ... 60-6 



16,2p.m. ... 34.6 ... 63-1 



Alkali Lands. On large tracts of land in many portions 

 of the earth's surface the quantity of soluble salts in the 

 surface soil is so considerable as to greatly hinder, or frequently 

 prevent, the use of the land for agricultural purposes. These 

 alkali lands occur only in climates having a hot summer, and 

 a small annual rainfall. When the rain which falls is all 

 evaporated from the surface of the soil, and no regular 

 percolation downwards into a drainage outfall takes place, 

 the conditions are present which favour the production of 

 alkali lands. 



Alkali lands occur to a large extent in Northern India, 

 in Australia, in Northern Africa, and in the western parts 

 of North and South America. In Europe they are found 

 to a more limited extent in Hungary. The condition of 

 such lands, and their proper mode of treatment, has been 

 made the subject of special study by Professor Hilgard and 

 his colleagues at the Agricultural Experiment Station of 

 the State of California. The information we proceed to 

 give is taken almost entirely from the Reports of this Station 

 for 1890-5. 



The limits of rainfall within which alkali lands are found 



P 2 



