344 JOUENAL OF THE EOYAL HORTICULTUEAL SOCIETY. 
of wood and foliage, which uselessly deprive the soil of mineral salts, 
whilst the resulting fruit is very coarse and thick-skinned, with little sugar 
or aroma and of bad keeping capacity. The time of ripening is also 
retarded, and it is necessary to consider whether this is or is not 
convenient. If, on the contrary, phosphoric acid is too abundant, the 
fruits are small but numerous, well flavoured and aromatic, with thin 
skins and poor pulp. When potash is superabundant, the tree does not 
grow very large, but the fruit is juicy, sweet, and of pleasant flavour. 
Accordingly, none of these three elements takes the place of a complete 
fertiliser : they complement each other ; they counteract each other' shad 
qualities and bring out the good ; and if used together, and in proper 
proportions, they produce the desired result. 
The general formula has been fixed for the use of large trees in full 
bearing, and taking for basis a crop of 30,000 kilos. (66,120 lb.) per 
hectare (2'471 acres). But if the plantation is in a condition to produce 
more by reason of its age, growth, kind of soil, and abundance of water, 
or because of the trees being naturally heavy bearers, or on account of 
the situation, climate, &c., there is no objection to increasing the quantity 
of fertiliser until you find out the limit of production. But if the planta- 
tion naturally produces small crops, has moderate-sized trees, and above 
all is not sufficiently irrigated, the same formula should be employed but 
in lesser quantity, and in the selection of this quantity is shown the good 
judgment of the grower. 
If the tree is not in full growth, the formula is modified. Later on 
will be given special formulae for young and old trees, for rickety trees, 
for those of much leaf and little fruit, for those afflicted with gum disease, 
and for those in the nursery. 
As a nitrogenous fertiliser, either sulphate of ammonia or nitrate of 
soda may be used. Koughly speaking, no preference can be given to 
either, and you may choose whichever is the more convenient for the land 
you possess. The sulphate of ammonia is successfully used in light soils 
and in those charged with organic matter ; the nitrate of soda is well 
applied to heavy soils. As will be indicated later, it is desirable to make 
use of both these forms of nitrogen. Of the phosphate fertilisers the 
preference is given to superphosphate of lime, and only in gypseous soils 
and those humid and rich in organic residues (low-lying lands and banks 
of lakes or rivers) should the phosphate ' Thomas ' be employed. 
Amongst the potash salts you may use indifferently the sulphate or the 
chloride ; however, the sulphate appears to give more delicacy and fragrance 
to the fruit. In rather limy soils the use of sulphate of iron is beneficial. 
In those with little lime, and especially if inclined to be rough and 
clayey, the use of gypsum will produce excellent results. It should be 
remembered that the Orange tree is a great absorber of lime, and that 
under normal conditions a good crop of Oranges extracts from the soil 
about 250 kilos, of lime (551 lb.) per hectare (2'471 acres). It is clear 
that if the soil is poor in lime, the roots find great difficulty in obtaining 
this absolutely necessary quantity of lime. Apart from this, copperas as 
well as gypsum operates as a corrective of the soil, setting the otherwise 
inactive potash at the disposal of the plants. 
Though the Orange tree may produce large crops by the use solely of 
