HORTICULTURAL SOILS. 
71 
The analysis of the soil shows that it contains the vast 
quantity of 640,000 lbs. per acre of organic matter when cut to 
9 inches deep, and gives 11,650 lbs. of nitrogen per acre. Such 
fibrous-rooted soils as the Ghent heath mould are of a light 
texture, and peculiarly suited to the growth of most greenhouse 
and conservatory plants. Their peculiar property is that they 
facilitate drainage and aeration, causing a quick and active 
growth with a free development of feeding roots; and thus are 
especially fitted for composting with other and stiffer descriptions 
of soils. 
The soil, then, as it results by the processes thus briefly 
indicated is a compound of coarse and fine materials, mixed with 
clay, silica, and chalk; together with a greater or smaller 
amount of organic matter, holding a variable but usually large 
quantity of moisture. 
Further, a soil rich in organic humus matter is rich in 
nitrogen; while a soil poor in organic substance is poor also in 
nitrogenous plant-food ; and the permanent fertility of a soil is 
found to be very closely connected with its power of retaining 
plant-food. 
Table IY. illustrates the percentage amount of five selected 
constituents—organic matter, nitrogen, potash, lime, and phos¬ 
phoric acid—in seven widely different descriptions of soil. The 
quantities quoted are in water-free soils. 
TABLE IV_ Selected Chemical Constituents in Different Descriptions 
of Soil. Quantities in 100 pounds of each, dry. 
Ordinary 
average 
loam 
Garden 
bedding 
loam 
Rich 
garden 
loam, 
[Rich 
pasture 
soil 
Leaf 
mould 
Peat 
mould 
(France) 
Heath 
mould 
(Ghent) 
Organic matter 
% 
3-84 
% 
4*05 
% 
8*46 
% 
14-55 
% 
17-00 
% 
18-80 
% 
64-00 
Nitrogen . 
0T3 
0-23 
0-45 
0-59 
0-47 
1-40 
1T7 
Potash 
0*20 
0-33 
0*73 
0-75 
0-50 
0-31 
0-14 
Lime 
0*66 
0*67 
2-08 
1-20 
0-18 
0-53 
0-35 
Phosphoric acid 
0T2 
0-48 
0T0 
1-00 
0-13 
0-20 
0-16 
The analytical results show that the proportion of plant-food 
present in soils is very small, even when the land is extremely 
fertile, the bulk of the soil serving chiefly as a support to the 
growing crops and as a sponge to hold water for their use. 
