but a small
quantity of phosphoric acid is removed by the crops, and as that manure is
firmly retained by the soil, bones need only be used at long intervals
provided lime is regularly applied in small quantities.

And next, before we can approach, or attempt to determine, the quantity of
manure required, we have to take into account the loss by wash, either
from the surface or by downward percolation, and the absorption of manure
by the roots of the shade trees. We have also to take into consideration
the manure returned by the shade trees in the shape of fallen leaves, and
the ammonia derived from the rainfall, so that it is impossible to state
with any approach to accuracy the amount of manure that should be
applied. We can only say then that, whatever the required amount may be it
must be very considerable, for in addition to the above-mentioned losses
of manure, we require a considerable amount for the demands of the coffee
trees, and that, further, it must vary with the amount of the rainfall,
and the retentive or non-retentive character of the soil. The crop, it is
true, takes comparatively little from the soil, and Mr. John Hughes,
Agricultural Chemist, 79, Mark Lane,--points out in his "Reports on Ceylon
Soils and Coffee Manures," that 5 cwt. of parchment coffee an acre, which
is an average crop over a long series of years, only removes from the
soil--

lbs.
Nitrogen 8-1/4
Potash 7-1/2
Phosphoric acid 1-1/2
Lime 1
------
Total 18-1/4

Assuming then, he tells us, that the small quantity of potash required
could be supplied by the soil, and that the pulp is returned to it, the
loss by the crops could be fully supplied by 100 lbs. of castor cake and
10 lbs. of bones per acre. Then if we require much more from the plant
than the production of crop (for we expect it, in addition, to grow wood
for the succeeding crop, and during this process the plant grows much
superfluous wood, besides suckers, which have to be removed), it must be
remembered that all primings and superfluous wood are left on the land.
What there is actually carried off it is really very small in quantity.
Why, then, it will naturally be asked, is it necessary that so much manure
should be present in the soil if we wish to grow good coffee and have
continuously good crops, and why is it that if manuring is neglected you
will soon find that it is only the r