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“Mineral Manures,’”’ which are extracted from minerals, and 
yield ash constituents to plants—e.g., sulphate of ammonia, of lime, 
of potash, nitrate of soda, of potash, lime, ete. 
Then again, manures are spoken of as “general” manures when 
they contain all the necessary elements for plant growth, or “special 
manures” when they only supply one or several of these elements. 
These elements, again, are said to be “dormant,” “latent,” or 
“active,” according as they are insoluble or soluble in the corroding 
liquid which exudes from the rootlets and are thus made “available” 
for plant food or are locked up in an inert form in the soils. 
Fertilisers, however, for the practical purpose of the fruit- 
grower and farmer, should be better considered as nitrogenous, 
phosphatic, potassic, calcareous fertilisers, according as nitrogen. 
phosphoric acid, or potash, or lime is the predominating valuable 
constituent. 
NITROGEN is the rarest and most costly element of plant 
food; it occurs in abundance in the air as free nitrogen, but is 
not available in that form to most crops, except those of the 
leguminous class, on whose roots are gall-like swellings known as 
root tubercles, which are formed under the influence of micro- 
organisms living in the soil. It has been found that the presence of 
these bacteria and root tubercles enables some plants to draw from 
the vast stores of nitrogen in the air a supply which will enrich the 
ground in that valuable element and enable it to grow more abun- 
dant crops. 
The more common source of nitrogen on the farm or at the 
orchard is found in farmyard manure, which consists of— 
‘Water xe 10 
Farm Yarp J Organic Matter 27—Nitrogen, -4 to -65 per cent. = 9 
Manvre. to 15lbs. per ton. 
Ash... .. 3 (Phosphoric Acid, -2 to -5 per 
se cent. = 4 to 10lbs. per ton. 
100°) Potash, -3 to -6 per cent. = 5 to 
13lbs. per ton. 
A good dressing per acre, 8 to 10 tons. 
If used by itself, it is a very expensive method of manuring, 
although cost varies according to localities and distance and facili- 
ties for haulage. It generally comes, when all charges are paid, to 
12s. per ton weight and sometimes more. Its value depends on its 
organic matter. On light sandy soils it helps to retain moisture; 
on stiff clay it prevents baking and keeps the soil open and spongy. 
In the case of fruit or vegetables, stable manure alone will not 
give maximum crops unless large quantities are used, and the cost 
of such manuring is greater than would suffice to produce the same 
result, if less stable manure were used, supplemented by concen- 
trated fertilisers. 
