SOILS. GENERAL CONSIDERATIONS. 105 



signs alone, for the subsoil is as important as the sur- 

 face above. If this be not sufficiently deep the beet 

 cannot penetrate to the required depth, and will there- 

 fore grow partly out of ground. If we suppose a soil 

 to be formed on a granite foundation, for example, it 

 would in all probability be barren, or nearly so, and if 

 on shales and sandstones indifferent or bad, whilst 

 those on nearly pure calcareous limestone might be 

 most productive. 



Then, again, the upper surface is frequently very 

 inferior to the lower, and combining the subsoil with 

 this the yield of roots might be most satisfactory. 



It frequently happens that the subsoil is compact, 

 and prevents the passage of water, thus producing 

 disease,^ etc., but can be improved by proper drain- 

 age. On the other hand, if too dry, all vegetation 

 becomes impossible. The beet in growing, like other 

 plants, requires three principal elements : water, car- 

 bon, and nitrogen, each of these having a special 

 function to fulfil. As they are not all contained in the 

 atmosphere, we can only conclude that they partly 

 exist in the soil. The carbon is required for the for- 

 mation of the sugar and the oxygen for the develop- 

 ment of the root, etc., but of the mineral elements that 

 are found in anal3^zing the plant, what their purpose is 

 we cannot exactly say, but evidently their presence is 

 necessary, not in excess, as the saccharine qualities 

 would be diminished, but in certain unknown propor- 



' See Chapter "Diseases of the Beet." 



