ashes, coffee pulp and parchment, and such chemical
fertilizers as superphosphate of lime, basic slag, sulphate of ammonia,
nitrate of lime, sulphate of potash, nitrate of potash, and similar
materials.

The relative values of these fertilizers depend largely upon local
climate and soil conditions, the supply, the cost, and other like
factors. The chemical fertilizers are coming into increasing use in the
larger and more economically advanced producing countries. Brazil,
particularly, is showing in late years a tendency toward their adoption
to make up for the dwindling supply of the so-called natural manures. As
the coffee tree grows older, it requires a larger supply of fertilizer.

[Illustration: THE FAMOUS BOEKIT GOMPONG ESTATE, NEAR PADANG, ON
SUMATRA'S WEST COAST

Showing the healthy, regular appearance of well-cultivated coffee
bushes, twenty-six years old. Also note the line of feathery bamboo
wind-breaks]

PRUNING. On the larger plantations, pruning is an important part of the
cultivation processes. If left to their own devices, coffee trees
sometimes grow as high as forty feet, the strength being absorbed by the
wood, with a consequent scanty production of fruit. To prevent this
undesirable result, and to facilitate picking, the trees on the more
modern plantations are pruned down to heights ranging from six to twelve
feet. Except for pruning the roots when transplanting, the tree is
permitted to grow until after producing its first full crop before any
cutting takes place. Then, the branches are severely cut back; and
thereafter, pruning is carried on annually. Topping and pruning begin
between the first and the second years.

[Illustration: COFFEE ESTATE IN ANTIOQUIA, COLOMBIA, SHOWING
WIND-BREAKS]

Coffee trees as a rule produce full crops from the sixth to the
fifteenth year, although some trees have given a paying crop until
twenty or thirty years old. Ordinarily the trees bear from one-half
pound to eight pounds of coffee annually, although there are accounts of
twelve pounds being obtained per tree. Production is mostly governed by
the cultivation given the tree, and by climate, soil, and location. When
too old to bear profitable yields, the trees on commercial plantations
are cut down to the level of the ground; and are renewed by permitting
only the strongest sprout springing out of the stump to mature.

CATCH CROPS. On some plantations it has become the practise to grow
catch crops between t