ash.

I have pointed out that phosphoric acid is retained by the soil, and it is
important to remember that it is only removed by the crops of coffee to
the extent of from one-and-a-half to two pounds per acre per annum, and
these are two facts that every planter should bear in mind when he
contemplates following the common custom of manuring with bones. For if he
remembers that about one-half of the bones consists of phosphate of lime,
and that about one-half of the latter consists of phosphoric acid, he will
at a glance see, when he estimates the amount of phosphoric acid removed
by the crops, that if he puts down even 100 lbs. of bones per acre he will
have put down enough phosphoric acid for about twelve crops of coffee. And
yet for a planter to put down 3 cwt. of bones per annum regularly is quite
a common thing, and a friend of mine, after having manured his land one
year with bones to a moderate amount, put down each year, for the two
following years, no less than three-quarters of a ton of bone-meal per
acre. So that, making a large allowance for the phosphoric acid taken up
by the shade trees, he had put down, in these last two years, enough
phosphoric acid to last for the crops of 300 years. From the application
of bones he had undoubtedly obtained a great benefit, but I feel sure that
it was from the lime and the nitrogen of the bones, for the application of
bones that preceded the two applications of three-quarters of a ton per
annum must have left the soil amply supplied with phosphoric acid. Now
assuming that the soil required lime, and a moderate degree of nitrogen,
these could have been supplied far more cheaply, and just as efficiently
had my friend applied a small dressing of ordinary lime, and some
oil-cake, and I am the more convinced of the accuracy of this view after
visiting Mr. Reilly's Hillgrove estate near Coonoor on the slopes of the
Nilgiri hills, and hearing the result of his very long experience. Bones
he had never used but once, and that on a small portion of the estate, but
he had always applied lime once every three years at the rate of about 4
or 5 cwt. per acre; the other manures he had used were cattle manure, and
town manure from Coonoor, and these added to the small quantity originally
in the soil, had supplied his coffee amply with the 2 lbs. of phosphoric
acid annually removed by the crops. After much consideration, and hearing
Mr. Reilly's views, it seems quite clear to me that as