The Science of the Soil m 



An average of the results of forty-nine analyses of typical soils in 

 America showed that the first 8 in. of surface soil contained 



Nitrogen 2,600 Ib. per acre. 



Phosphoric acid ... ... 4,800 



Potash 13,400 



In a good Hertfordshire soil analysed by Dr. Voelcker the following 

 quantities of plant foods were found: 



Phosphoric acid ... 4,569 Ib. per acre (over 2 tons). 



Potash 10,483 ( 5 ). 



Lime 74,188 ( 33 ). 



Magnesia ... ... 9,676 ( 4 ,. ). 



Sulphuric acid ... 4,569 ( 2 ). 



Nitric acid ... ... 22 



Nitrogen 2,397 ( 1 ton). 



The surface soil from 9 to 12 in. deep is usually regarded as being 

 more fertile than the subsoil beneath. Although farmers may accept 

 this statement, many modern gardeners question it, for experience proves 

 that by turning the soil over to a depth of 2, 3, and even 4 ft. mag- 

 nificent crops can be secured. Indeed this has been proved for centuries 

 by Chinese and Japanese gardeners, who are adepts at deep cultivation. 

 Of course if the upper 9 or 12 in. of soil only are cultivated and man- 

 ured it is possible to prove that it is richer in available plant food than 

 the layers of soil immediately beneath. But actual practice proves that if 

 the subsoil is also cultivated and manured, and brought up to be acted 

 upon by the weather, it will gradually yield up the foods it contains. 



The following comparison between the plant foods in the soil and 

 subsoil is worth consideration: 



Subsoil. 



53-71 per cent. 



3-96 



3-27 



7-15 



8-85 



0-21 



1-02 



1-89 



10-36 



0-49 



0-94 



1-32 

 6-83 



100-00 100-00 



With the exception of organic matter (which can be easily supplied 



