72 
JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
An ordinary average sample of loam is seen to contain 3*84 
per cent, of organic matter, 0T8 per cent, of nitrogen, 0*20 per 
cent, of potash, 0*66 per cent, of lime, and 0*12 per cent, of 
phosphoric acid. A garden bedding soil of fair texture will con¬ 
tain a larger proportion of available nitrogen, as well as other 
plant-food constituents, than the ordinary arable loam; the 
amount of nitrogen being nearly double, the potash considerably 
larger, and the phosphoric acid four times as much. The rich 
garden loam is about twice as valuable in the various chemical 
ingredients as the garden bedding mould ; the exceedingly large 
amount of lime—over 2 per cent.—would very materially assist 
in the active nitrification of the larger percentage of organic 
matter, which is shown to be nearly 8^ per cent. In fact, Pro¬ 
fessor Hilgard has pointed out that the presence of lime in a 
soil, especially when associated with humus, much increases the 
availability both of potash and of phosphoric acid, so that 
smaller quantities of these constituents suffice when extra lime 
is present. 
The rich pasture soil, in consequence of its extensive amount 
of grass-root fibres, contains in the sample quoted 14^ per cent, 
of organic matter, with 0'59 per cent, of nitrogen, about the same 
amount of potash as the garden loam, but only one-half the 
proportion of lime. The phosphoric acid, however, is exceedingly 
high, amounting to 1 per cent., being the richest in the series. 
The leaf mould contains 17 per cent, of organic matter, with 
nearly \ per cent, of nitrogen, a good quantity of potash, but 
only small amounts of lime and phosphoric acid. 
The peat mould of France is high in most constituents, 
especially in organic matter, and in nitrogen ; the potash and 
phosphoric acid are, however, somewhat low in amount. 
The Ghent heath mould is remarkable for its enormous 
quantity of organic matter. Much of this is stated to be in not 
a very advanced stage of decomposition. Consequently the 
quantity of fine mould passing through a J in. mesh sieve is found 
to be less than in the case of some other soils. These investiga¬ 
tions show that the great value of the Ghent heath mould and 
of the French peat mould for horticultural purposes rests 
mainly in the excessive amount of fibrous-rooted material or of 
leafy organic matter, with a correspondingly large amount of 
nitrogen. It is these constituents which by their abundance 
