"Dec. 1, 1893.] Supplement to the Tropical Agriculturist,''* 
431 
fection, that we quote the following passages on 
Mulching and Manuring from an exhaustive 
paper ou orange culture, written by Mr. Benson, 
Fruit Expert, for the September number of the 
Agricultural Gazette of New South Wales :— 
Mulching is another operation of great import- 
ance, as wlien properly carried out andiattended to 
tliere is probably no better treatment to keep tlie 
tn-es liealthy and vigorous. Mulching tends to keep 
the roots cool and to retain moisture in tlie soil for 
the use of the tree, as by the addition of organic 
matter the absorbent properties of the soil are much 
increased, thus rendering the soil better able to 
withstand dry Aveather. Mulching also tends to 
keep down weeds and prevents the soil from rapidly 
dying out. The best material for mulching is 
tiush Takings which consists mainlj' of semi- 
decomposed leaves and small brandies with a 
greater or less proportion of the top soil added, 
.9nd when there is plenty available there is no 
better material either as a mulch or as a manure 
for orange and lemon culture. If, however, bush 
raking cannot be obtained a good substitute is 
found in old stable-manure, rotting straw, or 
partially decomposed weeds or other rubbisli, 
or by growiug such green crops as the cow-pea or 
other strong-growing leguminous plantsand cutting 
them when coming into pod and placing them 
round the trees. Hot stable-manure should never 
be used as a mulch by itself as it is apt to injure 
the trees, but if it is desirable to use it fresh as a 
manure and mulch combined, it should always be 
mixed witli bush rakings or some other similar 
substance. 
Manuring. — In order to keep up the fertility of 
the soil it is necessary to replace the materials ex- 
tracted from it by the crop that has been taken off 
the trees, and to do this it is necessary to have re- 
course to manuring. This may either be done by 
tlie addition of ne;v soil to the orchard or by the 
application of farmyard or stable-manure or one 
or more of the various artiticial manures sold for 
I ho purpose. Manuring with fresh soil is only 
applicable where there is a quantity of new land 
adjacent to the orchard from which the surface soil 
can be taken, but in any case it is a very costly 
method of renovating an orchard, as the expense of 
carting and spreading is very great in proportion to 
the good accomplished, and also it is simply a case 
of robbing PeDer to pay Paul, as the land from 
which the soil is taken is impoverished to as great 
an extent as the orchard is benefited, and also the 
constant use of fresh soil tends to bury the roots 
of the trees too deeply unless the surface is 
continually being washed away. Of course in the 
case of wash-outs where the soil is removed from 
around the roots of the trees it is always necessary 
to cart new soil and spread it round the trees ; 
l)at, except in this case, tlie use of stable-manure 
or artificial manure combined with proper mulch. ng 
is preferable to the addition of fresh soil. Stable- 
manure acts as an all round fertiliser and supplies 
all tlie necessaiy plant food*, and in the case of 
stiff soils it has also a beneficial effect by im- 
proving the mechauical coudition of the soil, thus 
rt'uderiiig it more easily cultivated. The great 
drawback to the use of staljle-manure is that the 
cr)st of its a|)plic ilion, owing to the bulk it 
occupies as cjinp.ircJ with itj mauurial value, is 
much greater than Ls the case with artiticial 
uiaiiurei, and also by its means large quantities of 
weeds are introduced into the soil, thus causing 
extra expense in cultivation to keep them in check. 
Artificial manures ou the other hand are in a con- 
ceutrated and easily-handled form, the fertilising 
ingredients they contain being in a more or less 
soluble form, and thus readily available tor assi- 
milation by the plant or tree. The principal 
ingredients required by the orange for its proper 
development are lime, phosphorus, potash, and 
nitrogen, and if the soil is deficient in any of these 
materials the deficiency must be supplied before 
it can be made to produce the best returns. Lime 
should always be applied by itself, as, if used in 
conjunction with manures containing nitrogen, it 
will free the nitrogen contained in them, causing 
it to pass off in the form of ammonia vapour, and 
so be lost. Lime is best applied in the autumn or 
winter by being .spread evenly over the surface 
of the ground, and then lightly ploughed in. 
Previous to spreading, it should be allowed to 
stand in heaps in the orchard for a short time so 
as to become partly air-slacked, when it can be 
easier and more evenly distributed, but if the soil 
is sour and stiff the lime is best applied hot. Lime, 
in addition to its manurial qualities, has also a 
chemical effect ou the soil, as it neutralises the free 
vegetable acids that sour the land and also tends to 
break up the clayey matter of the soil, thereby 
liberating the potash it contains and rendering 
the land more friable and therefore more easily 
worked. Lime should never be ploughed in too 
deeply, it will sink fast enough by itself. Phos- 
phorus is obtainwd mainly from bones, coprolites, 
and phospatic guanos, but a new and cheap source 
is basic slag. Phosphates are usually applied to 
the soil either in the form of ground bones, or 
bone-meal when they are in an insoluble condition 
and not available for plant food till they have 
been rendered soluble by the carbonic acid gas 
dissolved in the water contained in the soil, so 
that their action is slower and more lasting than 
in the case of the other class — " superphosphates," 
where the insoluble phosphates have been ren- 
dered soluble by being treated with sulpliuric acid. 
Thus, if a quick result is desiied, you use tlie 
soluble phosphates, and if a slower and more 
lasting result is wished for use the insoluble or 
slowly-soluble phosphates. Generally speaking, 
the best results are derived from an admi.vture of 
the two kinds, as the soluble phosphates stimulate 
a rapid growth and the slowly-soluble phosphates 
maintain the growth when started. 
Potash is usually applied either in the form of 
kaiuit or of sulphate of potash, and, a> a rule, 
except in soils very deficient in potash, it is better 
to apply it in conjunction with a mixture of 
phosphates rather than alone, so as to obtain the 
best results. Nitrogen is applied in the form of 
dried blood, and in the refuse from meat works 
and boiling-down establishments, when it is 
always combined with more or less organic 
matter and phosphates. In such circumstances it 
is often in not a very readily available form, and 
its action is in consequence much slower than in 
the case of the other forms in which it is applied to 
the soil, the principal of which are sulphate of 
ammonia, nitrate of soda, and nitrate of potasli 
(saltpetre). Of these latter the one almost »'.v- 
clusively used in this Colony is the sulphate of 
ammonia, which is obiaiued as a by-product in 
the manufacture of coal gas. Sulphate of uiu- 
