THE GARDEN ALBUM AND REVIEW. 
75 
RELATIVE VALUE OF MANURES. 
Not the least important feature of gardening 
is that which deals with the feeding or manuring 
of plants. Scientists have discovered that the 
foods which are absolutely essential for all 
green-leaved plants are carbon, oxygen, 
hydrogen, nitrogen, phosphorous, potash, lime, 
sulphur, magnesia, soda, chlorine and iron, to 
which may be added silica. All these, how¬ 
ever, are not of equal importance from the 
gardener’s point of view—although the absence 
of any one of them would be detrimental to 
the health of the plants. Most of the foods 
mentioned are provided free of charge and in 
sufficient quantity by nature. Others are also 
present in a state of nature, but unfortunately 
in such a form that they are of no value until 
they have undergone various chemical changes. 
Nitrogen for example, although it forms four- 
fifths of the atmosphere, and is one of the most 
important plant foods, is quite useless until it 
becomes converted into nitrates in the soil. 
From a practical point of view, those foods 
that are easily procured may be eliminated. 
The question then resolves itself into one con¬ 
cerning those foods that are more difficult, and 
therefore more costly, to obtain. The most 
important of these foods are the nitrates, 
phosphates, and potash, and all the efforts of 
the manure merchant are devoted to the pro¬ 
duction of materials rich in all or any of these 
three substances, and in such a state that they 
are more or less readily soluble in water. 
Lime, although not mentioned in the same 
way as nitrates, phosphates, and potash—no 
doubt because it is cheaper, and more easily 
obtained in one form or another such as lime¬ 
stone, chalk, gypsum, or marl—is nevertheless 
one of the most important of plant foods, and 
should always be present in every good garden 
soil. Indeed, without it the other chief foods 
would be practically useless, and where stone 
fruits like Peaches, Nectarines, Cherries, 
Apricots, Plums, &c. are concerned, lime in 
the soil plays a most important part in the 
development and ripening of the crops. It 
has been estimated that an acre of fruit trees 
require about 200 lbs. of lime, 150 lbs. of 
potash, 75 lbs. of nitrates, and 50 lbs. of 
phosphoric acid in the soil to mature properly, 
and these figures will show the relative im¬ 
portance of these four principal foods. 
Excluding lime specifically, there are many 
manures on the market varying in value 
according to the available nitrates, phosphates, 
or potash, they contain. The following table 
shows at a glance the approximate number of 
pounds of each of these foods contained in one 
ton of the raw material. It will be noticed 
that very few of the manures—only those 
marked with an asterisk—contain all three of 
the important foods ; some contain two, and 
others again only one. The chemical manures, 
such as nitrate of soda, sulphate of ammonia, 
basic slag, etc., although containing a far larger 
percentage of food to the ton, are less safe for 
the novice to deal with than such natural 
manures as those of the stable or farmyard, 
the pigeon-loft or poultry-run, and great care 
should be exercised in their use. Indeed 
nothing can be safer than the natural manures 
when they have passed from a rank hot con¬ 
dition into a well-decomposed state. The 
chemical manures, however, may be used as 
stimulants where the soil has already been 
deeply dug and well-manured in the usual way. 
Table showing the approximate quantity 
of Nitrates, Phosphates, and Potash 
CONTAINED IN ONE TON. 
NAME. 
<5 
G/ 1 
C v 
!£o 
a,— r- 
z = 
r | r- 
-I' 
E n 
£C E 
Pounds of 
POTASH 
in One Ton. 
Basic Slag (Thomas’ 
Phosphate) 
400-400 
Blood, dried . 
280 
— 
— 
Bone Ash . 
— 
80O-9OO 
— 
,, Dissolved 
50 
3 °o- 35 o 
— 
„ Flour . 
3 ° 
45 °- 5 °° 
— 
,, Steamed 
560-600 
— 
Cambridge 
Coprolites 
560 
Carolina Phosphates 
— 
560 
— 
Coal Ashes . 
— 
15-20 
56 
'"Earth Closet Manure 
6-12 
10 
9-15 
'"Farmyard Manure... 
9 -i 5 
4-9 
9- I 5 
Guano, Fish. 
O 
O 
1 
to 
0 
0 
200-300 
— 
,, Peruvian ... 
186 
350-400 
67 
Horn Dust . 
260 
Kainit . 
— 
— 
302 
Leather Waste 
67-168 
— 
— 
Meat Meal . 
260 
— 
— 
Muriate of Potash.. 
— 
— 
1120 
Nitrate of Potash ... 
3 I 3 
— 
io 3 ° 
Nitrate of Soda 
358 
— 
— 
'"Pigeon Manure 
7 2 
48 
25 
'"Poultry Manure ... 
18-25 
12-24 
8-12 
'"Rape Cake . 
100 
40 
33 
'"Seaweed . 
10 
10 
30-40 
Sewage Sludge 
10-40 
10-25 
'"Soot . 
90 
25 
25 
Shoddy . 
75-244 
— 
Sulphate of 
0 Ammonia 
45 ° 
Sulphate of Potash.. 
900- 
Superphosphate ... 
_ 
270-290 
1200 
Wood Ashes . 
100-145 
! 35-224 
In connection with this subject an interest¬ 
ing article appears in the last number of the 
“ Journal of the Board of Agriculture ” by Dr. 
E. J. Russell. The author points out that 
in general most organic manures serve one or 
more of four purposes, viz.:—(i.) to increase the 
supply of plant food in the soil; (ii.) to improve 
the mechanical condition of the soil; (iii.) 
retention of moisture : and (iv.) to favour the 
growth and work of micro-organisms in the soil. 
