YMt TROPICAL AORICULTURIST. [October i, 1891. 
Theoretically a very poor soil has sufficient materials 
for a great uamberof crops, practically it has not; hence 
the value of manures. 
There is a general law of the greatest practical im- 
portance to all agriculturists and planters, viz : " That 
if a soil he deficient in any one elemest, no manure is of 
value on that land that does not supply the deficiency. 
For instance in England practice has shown phosphoric 
acid to be the element required by turnips, and as a 
rale phosphatio manures produce good results ; bat if 
the soil is short of nitrogen or potash, manures supp ly- 
ing only phosphates will be of little or no value. 
Again if the soil be short of iron or sulphnrio acid, 
wonderful results may be got by the application of iron 
sulphate in moderate doses ; but if there happens to be 
a large quantity of ferrous salts alr,°ady in the land 
the results are nil or worse, the crop may be 
killed off. Gypsum, i, e. Sulphate of Lime, is often 
very useful where lime and sulphuric acid are 
required, as it supplies them cheaply especially, when 
a super phosphate is used, as only the soluble phos- 
phates are paid for. 
Every agriculturist is familiar with the fact 
that repeated applicationa of lime exhaust tho laud 
unless they are well backed up by manure. This 
results from the circumstance that lime readers the 
nitrogenous matter of the soil more easily assimil- 
able by the plant, the ammonia acts as a power- 
ful stimulant and the increased energy of the plant 
enables it to absorb such food as the roots come in 
contact with more rapidly. The foil is exhausted when 
any one of the elements of fertility is reduced in quan- 
tity below that necessary to supply the immediate 
requirements of the plant in an easily asssimilkble 
form. There may be plenty of the element in the soil, 
but so shut up by its combination with silica &<•. that 
it is not immediately available as plant food ; the 
value of comparative soil analyses which enable us to 
judge what is necessary to supply the deficiency of the 
aoil ia of primary importance, as we are by them able 
to render the necessary assistance to the soil, that is 
supply a manure that will remedy the defect. To 
quote Sibson and Dr. Voelcker :— "The infertility of a 
soil is often explained by an analysis; the soil may be 
suffering from the want of some material inde^peueible 
to the growth of plants, or it may contain eomethiog 
poisonous to plants; in either case chemistry is generally 
able to enlighten us and to point out means of remedy- 
ing the evil. Of a soil whose fertility is impared we 
can all pronounce that it wants mauuring ; but with 
the assistance ot an analysis we may also learn in what 
substance the soil is deficient or what kind of manure 
it wants. With this knowledge we may restore its 
fertility in the most economical manner." As pointed 
out in my paper on coffee manures, soil analyses settle 
many vexed questiona of cultivation ; they decide tbe 
queatioQ as to whether the land requires drainage ; 
whether shade should be thick or thin, but the greatest 
value to the planter lies in the fact that tbey enable him 
to get full manurial value for his money. Having 
eettled what the soil requires we must next enquire 
what the plant demands. Unfortunally there is no 
royal road to this end. Experiments on soils of known 
composition with widely varying conditions, of climate, 
soil, &c. are needed to finally settle the question. 
The cereals and root crops of Britain have been and 
are the subjects ot constant study and experimtut. 
Lawes and Gilbert's work has done much to solve 
many abstruse questions and to place the cultiva- 
tion of cereals and root crops in England on a scien- 
tific basis, .enabling her to compete with the prairie 
lands of America, Australia and the cheap labour of 
India in the growth of wheat and other crops. Such 
experiments are much needed in connection with Tro- 
pical Produce. It was the want of such experiments 
in regard to coffee, tea, cocoa, &o. that led me iu my 
piiper on coffee manures to eay that " The question 
of manuring coffee has had little systematic work 
spent on it, compared with the vast interests nt 
stake. " Had I said •' little systematic experimental 
work," most people would have agreed with me. I 
was fully aware of the valublo work done by Messrs. 
Marshall "Ward, Morris, Thwsitos, Iriraeu and others 
in connection with llemileia vantati'ix. The thorough 
eystematio investigation of that pest is deserving of 
the highest pr.iise: I consider th«t the thanks of the 
whole coffee planting community are due to the before 
named gentlemen, the Ceylon Pluuters, Gnvernment, 
and Observer newspaper for the energy nnd ze*l dis- 
played in their crusade against tho pi'st ; the informa- 
tion gained is of inestimable value in guiding fuiure 
investigations. 
Hnghes' analyses I know and fully appreciate the 
value of, but I would like to see Bjatematic experi- 
ments put iu hand to determine what is to use Ville's 
words the " dominant element" required in a 
maoure for coffee, tea, cocoa, and oiher tropical 
products. Having found the duoiinant element we 
must first supply the deticieucy — (if any oxiet?, 
and thu probability that it does is great ) in tbe soil, 
then apply it. From the view of a pUut, tew soils are 
complete; a complete toil should gruw any aud every 
plant eqU'illy well provioed the clio-ate is equally 
suitable; it's only a question of £ s. d. With suitable 
manures yon can grow plants in calciued tand. Coffee 
Arabica con be made tj jield a ton per acre; on 
small block<* eay up to 5 acres or so, it pays to spend 
R200 to E300 per acre per aonum aud pick crops of 10 
cwt. to a ton. But when we come to 2(J0 to 1,000 
acres or more, the labour difficulties vra so great that 
such cultivation is a practical impossibility. An aver- 
age of 5 cwt. per acre must for coffee under shade 
with ordinary work and manure be cotisidered good. 
Except on very poor land, and patches of such exist 
on every estate, such crops can be got iu South (Joorg. 
The crop of one block of estates there has 
averaged 4 cwt. per acre per annum for the last ten 
yearo, aud there are other b ocks as good ; individual 
estates with much higher averages are to ':e teen 
throughout the district. 
There is every prospect of the average being raised, 
as the labu'Ur difficulties are overcome and tho ge neral 
work can be kept well in han't, allowing of steady 
sys:euiatic annual broadc.ist manuring being carried 
out at the right time. There is little doubt ihit it is 
best to manure every portion of the eatate yearly, but 
under some circumstanoi s if the labour is suffiuiciit, 
twomanurings would be better for tbe trees. Last year 
(1890) South Ooorg was no better off for labour than 
her neighbours ; the evil hffeets were p inti d i ur, and 
the district best rred itself and procured cooi es to re- 
place the Cannrese. Tamil labeur was introduced ; 
coolies were not paid off at the usual time, but were 
retained as long as possible. All the supply pits re- 
quired for perceptible vicaucues were cut iu the hot 
weather, the weeds were kept down, and 1 hid the 
pleasure ot seeing supplying briskly proceeding e.ii ly 
in June. 
Leat diseafe (lu Oooig) in the hot weather receives 
nsevete check a id I do not think that wnere tbe laud 
is well and dee cultivated ani' efficiently mauuri d 
that th' re is mv - ' of it on well drained lind kil- 
ling off the treef-. ; . there is no deujing that it does 
of ten seriously . it' et crops. A tree ca:inot esert it's 
otiergies to producb leaves when bearing crops, without 
dropping some of it. Bffi ieutmauuics adapt;d to the 
necessity of the plant ■'ud the deficiences of the soil 
are of the greatost assist ince. 
Too much stress as regards manures for coft'oe ha? 
been laid on the composition of the bean, and toj little 
attention devoted to the leaves and pruninge. Take 
Marshftll Ward's figure?, twetty-one weeks ss the 
duration ot the life of a i otfee leat, tlie tree muat sbej 
all its leaves 2g times iu a ^e.r; under shaae they 
remain a little longer, but the trees as a rule certainly 
renew their leaves at least twice a year. This loss on 
a healthy tree is not noticed as it proceeds all the 
year round. It is a jiojr tree of seven years growth 
that h-a not at some period of tho yea- at least fifteen 
hundred leaves, a fair average tree will have over two 
thousand, and a first clas-i one in full leaf as many as 
three thousand or more. Then there arc the prucijgs. 
Let practical p'anters experiment as Mr.Cameron f.l.s. 
of the Botanical Gardens, Bangalore, suggested to me 
the other d ly : euiroundiug a trees with wire 
netting, collecting the lenves and pruuings weekly or 
monthly, dry and weigh thorn, and have them analysed. 
