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value may be taken at about 7s., delivered on the land. If it 
cannot be obtained delivered on the ground at that price, it is 
almost certainly cheaper to buy the plant foods from other 
sources. You will see that farm-yard manure contains less phos- 
phoric acid than it does nitrogen and potash, therefore in using 
this manure on average soils, such as the orchard soils 20 miles 
round Melbourne, it should be supplemented with superphosphate. 
To obtain from average farm-yard manure the same result as we 
could from the mixtures above described we should have to use it 
as follows :—10 tons per acre stable manure, containing 100 lbs. 
nitrogen, 601bs. phosphoric acid, 100 lbs. potash, at 7s., £3 10s.; 
and 4-5th ewt. concentrated superphosphate, containing 36 lbs. 
phosphoric acid, at 18s. 43d., 10s. 8d.; total, £4 Os. 8d. 
Let us place these different methods of obtaining the same result 
side by side and compare the cost :—1. Special orchard manure 
mixture, cost £7 per acre. 2. Stable manure and superphos- 
phates mixed, cost £4 per acre. 3. Blood manure, concentrated 
superphosphate and potash salt, cost £3 2s. per acre. 4. Dried 
night-soil, cost £1 10s. per acre. No. 3 of the above methods 
has the advantage of the others, namely, that its composition is 
just what you like to make it, and you can make it to be just 
what the soil requires. In all the other cases you may be pay- 
ing for material which the soil does not require. If the soil does 
not require potash, you cannot leave the potash out of the stable 
manure or the night-soil. No. 4, however, is so cheap that even 
if the potash it contains is not required still you get the value of 
the money in other plant foods. The only objection to this last- 
mentioned manure is the odour, but this is by no means so strong 
as in the undried night-soil ; and the disease germs which might 
have been contained in it have been destroyed by heat. 
The extreme variability of manures, as shown by the table at 
the end of this lecture, will indicate the advisability of always 
buying them according to the results of analysis. There are no 
respectable manure merchants who will not sell on these terms. 
Buying without analysis is worse than buying a pig in a poke, 
for if the pig be not worth the money given the loss is no great 
thing, but if the manure be not what the soil requires the loss 
is one affecting a whole season’s yield from every acre of ground 
that has been manured. 
One word more before leaving the subject of stable and farm- 
yard manure. It is often said that these small concentrated 
manures will not have the same mechanical effect on the soil that 
the bulky farm-yard manure has. This is true, but where such an 
effect is required it can always be obtained by green manuring. 
And by green manuring with peas or beans the soil not only 
becomes broken up and rendered lighter and more porous, but the 
peas and beans, like all leguminous crops, indirectly cause the soil 
