x.] SANDY SOILS 321 



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. Owing to the small quantities of water 

 retained by the soil, basic slag is better suited for the 

 permanent enrichment in phosphates of a sandy soil 

 than for the feeding of a particular crop, though 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 



Y 



