SOIL ANALYSIS AND ITS INTERPRETATION 337 



2. If swedes, turnips, or cabbages get finger-and-toe 

 rather badly. 



The Armstrong College experiments have shown that 

 2 tons per acre of ground lime, or 3^ tons per acre of 

 ground limestone, afford suitable dressings in this case. 1 



3. If mayweed springs up vigorously among the wheat, 

 or if spurrey, sorrel, or bent grass become prevalent. 



Land that has been wet through the winter ought to 

 have lime in the spring : otherwise uneven patches may arise 

 in the field on which weeds develop and the crop ripens 

 unevenly. 



Neither lime nor limestone, however, should be applied to 

 potatoes or oats unless actual trials have shown that benefit 

 will be obtained ; as a general rule these two crops respond 

 less than others : and in the Kilmarnock trials, 2 lasting over 

 eight years, potatoes were actually injured by lime, though 

 oats benefited by it (p. 244). 



Basic slag reduces the need for lime, but superphosphate 

 does not. Sulphate of ammonia increases the need for lime. 

 Instances of soils known to respond to lime are given in Table 

 XC. 



TABLE XC. CALCIUM CARBONATE CONTENT OF SOILS KNOWN TO RESPOND 



TO LIME. 



1 Armstrong Coll. Bull., No. 12, 1915. 



2 West of Scotland Agric. Coll. Bull., No. 55, 1911 (pp. 193-222). 



3 The numbers are those used in Soils and Agriculture of Kent, Surrey, and 

 Sussex (Hall and Russell). 



22 



