SOILS. 



composition, and that 30*5 per cent of this was 

 cane-sugar, whereas previously it had always 

 been considered of a glucose nature. 



The second year's plants were found to con- 

 tain in their different organs the following con- 

 stituents : — 





Dry 



Substance. 



In the Dry Substance. 



Parts of Plant. 



Nitrogen. 



Mineral 

 Matter 



(Ash). 



In the leaves, 



In the stem, 



In the roots, ... 



grammes. 



1293 



1007 



993 



grammes. 



24-04 



11-27 



9-53 



grammes. 

 33-43 

 42 30 

 52-63 



Total plant, 



3293 



44-84 



128-36 



It is of interest to notice that during the 

 second year of growth of the Azalea, as was 

 observed in that of the first year, the maximum 

 of nitrogen was found in the leaves. While, 

 however, in the first year the quantity of nitro- 

 gen contained in the roots was greater than 

 that in the stems, the contrary was found to be 

 the case during the second year of growth. 



The mineral substances abstracted by the 

 Azalea from the soil during its second year 

 were as follows: — 



(Quantities in 



grammes. 



► 





Constituents. 



In 

 Leaves. 



In 

 Stems. 



In 



Roots. 



In Total 

 Plant. 



Lime, 

 Potash, 

 Phosphoric acid, 



Iron oxide, 



Silica, 



6-31 

 2-96 

 2-29 

 0-57 

 15-37 



9-18 

 6-00 

 2-43 

 0-72 

 11-50 



1-12 

 4-36 

 1-68 

 0-94 

 41 v5 



16-61 



13-32 



6-40 



2-23 



67-92 



These results prove that the Versailles leaf- 

 mould provides even in the second year a suffi- 

 cient amount of nitrogen for the requirements 

 of the Azalea plant, although the Ghent mould 

 places at the disposal of the plant a greater 

 excess of this element. In regard to mineral 

 substances, the two soils furnish in the second 

 year the following proportions : — 



Constituents. 



Ghent 

 Mould. 



Maurepas 

 Mould. 



Lime, ... 



Phosphoric acid, 



Potash, 



grammes. 



110-11 



17-61 



25-00 



grammes. 



55-68 

 12-58 

 31-46 



Each of these soils provides the plants with a 

 sufficiency of mineral food, but the Ghent mould 

 gives much the larger quantity of lime and 

 phosphoric acid; and it is important to note 

 that the plants utilize more food during the 

 second year's growth than during the first. It 



is concluded, therefore, that as during the 

 second year's growth of the Azaleas the assimi- 

 lation of plant-food is more rapid, it is necessary, 

 for the purpose of bringing up the French 

 moulds to the standard of the Belgian, that an 

 application be made of superphosphate with a 

 small quantity of nitrate of soda. 



It was found that at the end of the second 

 period the plants had made twice as much dry 

 substance of roots as at the end of the first 

 period in an equal area of soil, consequently 

 the assimilation of food was facilitated, and 

 explains the cause of the greater vegetative 

 powers of the Azaleas during the second year 

 of their culture. 



Third Year of Growth. — In the month of May 

 of the third year the Azaleas are planted in a 

 bed of leaf -mould, about forty plants to the 

 square yard, this being the last change of soil 

 to which they are submitted before their con- 

 signment for sale in the following September. 



The amount of plant-growth produced dur- 

 ing the third year is shown by the following 

 results : — 



(Quantities in grammes.) 



Parts of Plant. 



Dry 



Substance. 



Nitrogen 

 in Dry. 



Mineral 

 Matter 



(Ash). 



In the leaves, 



In the stems, ... 

 In the roots, ... 



1052 



576 

 801 



19-57 

 6-45 



7-68 



39-63 

 24-19 

 42-43 



In total plant, 



2429 



33-70 



106-25 



The mineral matter on being submitted to 

 analysis gave the following results : — 



(Quantities in grammes. ) 



Constituents. 



In 

 Leaves. 



In 



Stems. 



In 



Roots. 



In Total 

 Plant. 



Lime, 



Potash, 



Phosphoric acid, 

 Iron oxide, ... 

 Silica, 



7-30 

 3-51 

 2-72 

 0-61 

 18-39 



5-25 

 3-33 

 1-39 

 0-41 

 0-70 



0-90 

 3-51 

 1-35 

 0-72 

 33-19 



13-45 



10-35 



5-46 



1-74 



52-28 



These figures show that during the last 

 twenty-seven months of their culture the Aza- 

 leas find in the leaf-mould in which they are 

 grown a sufficient quantity both of nitrogen 

 and of mineral substances to supply their wants, 

 the Ghent mould, as before, giving the greater 

 excess. The soluble plant-food is much less 

 drawn upon for nutrition in the third than in 

 the second year of growth. 



The general conclusions of the investigation 

 may be briefly summarized as follows : — 



