TREATMENT OF ALKALI LAND 225 



perfectly similar band of salt occurring in the soil of the 

 laboratory experiment, the results of which have been already 

 given in the Table on p. 202. The salt in this alkali land 

 owes its position to the winter rains ; these, as already men- 

 tioned, occur from November to March. These rains have 

 been sufficiently continuous, and sufficient in quantity, to 

 carry the greater part of the salts to the depth indicated ; and 

 the salts have afterwards gradually spread upwards, partly by 

 diffusion, and still more by the movement of water towards 

 the surface as a consequence of summer evaporation. 



The soil in question was examined next in September. 

 The results given in the table show that a distinct, but not a 

 great movement of the salts towards the surface has taken 

 place since the examination in May. As soon as a soil becomes 

 dry, all movement of salt will of course cease. In the case 

 of this soil it is clear that the alkali is doing a minimum 

 amount of injury ; the main portion of it does not reach the 

 surface even at the end of the summer. 



In the case of the reclaimed land growing good barley, 

 mentioned at the foot of Table XXXVIII, we have a further 

 illustration of the position which the band of salts occupies 

 in the soil in March shortly after the rains have ceased, and 

 of the higher place which it takes as summer advances. The 

 differences in the total quantity of salts found at the three 

 dates of sampling this soil must not be insisted on, as the 

 distribution of the salts in alkali land is always more or less 

 irregular, depending largely on differences in the physical 

 character of the soil. 



By the side of the results furnished by the natural soil in 

 Table XXXVIII will be found the results obtained at the 

 same time from a soil of similar character which had been 



Q 



