X.] SANDY SOILS 277 



liberal use of lime, frequently renewed because of the 

 ease with which water percolates and removes the 

 calcium carbonate. Marling and chalking, wherever 

 such materials are available, are better for the land 

 than the use of quicklime, which is apt to induce too 

 rapid an oxidation of the organic matter. Nitrogen is 

 best supplied in its organic forms, as in well-rotted dung, 

 the guanos, fish or meat manure, rape cake, etc. ; nitrate 

 of soda is apt to induce too rapid a growth, and also to 

 be washed away. Sulphate of ammonia is unsuitable, 

 owing to the lack of lime in the soil. Of phosphatic 

 manures, superphosphate is unsuitable owing to its 

 acid nature. Basic slag is also unsuitable as a rule, 

 owing to the small quantities of water retained by 

 the soil, but it answers well on sands where the 

 water table is near the surface; on the whole, 

 neutral easily available phosphates like phosphatic 

 guano and steamed bone flour give the best results 

 on these soils. Potash manures are much needed, 

 and either kainit or sulphate of potash may be used. 

 Gypsum is often used with good effect on such soils 

 in the Wealden area, acting as a liberator of what 

 little potash may be in the soil. 



The natural flora of the sandy soils is of a double 

 character — in part xerophytic, and associated with the 

 prevailing dryness of the soils; in part calcifuge, 

 and dependent on the absence of calcium carbonate. 

 Plants with mycorhiza are abundant, owing, as already 

 explained, to the comparative poverty of these soils 

 in both water and soluble salts. 



The characteristic sand trees are the Spanish 

 chestnut, birch, holly, and many conifers; of these 

 the Spanish chestnut and some of the firs, like 

 Pinus pinaster, are particularly intolerant of calcium 

 carbonate. 



