68 
JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
TABLE II. —Mechanical Analysis of Different Descriptions of Soil, 
cut to 9 inches deep. 
Arable 
loamy 
soil 
Rich 
pasture 
soil 
Alluvial 
pasture 
soil 
Rich 
water 
meadow 
soil 
Heath 
mould 
(Ghent) 
Gravel .... 
% 
8-7 
/o 
9*2 
% 
0*3 
% 
1*6 
% 
0*0 
Sand .... 
62-9 1 
28*1 
72*2 
51*4 
34*0 
Clay and chalk 
19-9 
52*7 
20*1 
11*1 
2*0 
Organic matter 
8*5 
10*0 
7*4 
35*9 
64*0 
Total . 
100*0 
_1 
100*0 
100*0 
100*0 
100*0 
The quantity of gravel is seen to range from less than 
\ per cent, to over 9 per cent. The sand ranges from 28 to 
72 per cent. The clay, including lime and soluble silica, ranges 
from 2 per cent, in the Ghent heath mould to about 52J per 
cent, in the rich pasture soil. The organic matter ranges from 
about per cent, to 64 per cent. The Ghent heath mould is 
composed of more than five-eighths of its total weight of 
organic matter. It may, therefore, be easily understood that 
the ready-formed plant-food in soils, whether of mineral con¬ 
stituents or of nitrogen, is a very fluctuating quantity, often 
falling below the needs of a particular crop, as regards one or 
other ingredient. It is only the very rich virgin soils, formed 
by breaking up of natural pastures of newly settled countries, or 
such soils as the Ghent heath mould, as quoted in Tables II. 
and III., that are practically inexhaustible. 
The Soil as a Source of Plant Food. 
In order to start with definite notions about the inherent 
fertility of soils, I may state that where any plant, however lowly, 
has once grown and died away, its remains gradually decay and 
add a little vegetable or organic matter to the soil, rendering it 
thereby capable of growing a better plant the next season. 
As the soil becomes richer in carbonaceous and vegetable 
matters, higher organised plants will occupy it; these pass 
through the same phases of fife as the plants of simpler 
structure, and enrich the soil at an increasing rate by the 
expanded flora, as well as by the greater bulk of their products 
