The Hawaiian gazette. [volume] (Honolulu [Oahu, Hawaii]) 1865-1918, 1916-05-23
SCIENTIFIC EXPERT
6N1ROP|CAL NEEDS
Hawaiian Experience Agrees
With Summary Of Tropical
characteristics BY WoItmann

the importance mat ~ has Tor temper
ate zone crops, though it il very inpor
tant for some Of them notably cacnr,
vanilla, coffee and PEPPER" Professor
Woltmann states in has work on the Re
lection of land for trop,cal plant atioPs.
. From review Of the experience on
all kinds of tropical plantations, VOLT
mann 8 summary, AZ it applies to crops
produced in these Islands AS well as in
other lands, follows.
Special Requirements
''o0fee- Requires in the first place
q soft soil, moderately moist, and rich
in plant food, so that it does not thrive
on poor sandy soils, or on lateritic
ones.
Vanilla Demands humous soils,
moist c0mpOsts rich in plant food.
''Stsal Hemp-Is suitable for those
districts wheP the conditions of moist
ore are not of the best being satisfied
with twelve to twenty inches of yearly
rainfall.
"Cotton-Grows on all kinds of
soils except Pcaty or purely sandy
ones; nevertheless, account has to be
taken of the subsoil and of the climate,
and varieties must be selected which
can avail themselves of two or three
months rain.
fRubber-Has no special require.
ments, save for the Gncness Of texture,
which maintains that moisture which
seems to greatly favor the formation
of latex. Tan Acacias prefer the dry
soils Of arid regions. Peanuts like deep
nnH anff ontla ~ NJ Srifh
sufficient lime and enough water for
growth during the first few months.
Ldkes and Dislikes
''Cocoiuts- on all soils ex-
cept those containing stiff clay, either
on the surface or in the subsoil. The
best are, sandy coral soils and basaltic
soils even if rocky, provided they have
undergone weathering to clay.
'BananaS-DO not like clayey soils
otherwise they grow everywhere, ben.
| eftting by organic manuIing.
"Tobacco-Prcfers soft, warm, deep
humous soils rich in plant food and
with sufficient potash. Maize and
yotghuu have no special requirements
and will grow anywhere. Tuber and
rhtzome crops, many species of which
form the staple of the natives food
thrive best on loose, soft, deep humoui
soils free from stones
Some Crops Need Lime
Arid soils in,ths tropics are, usually
very rich in lime, he states, while moist
mes contain very little of this element
Nov certain crops require lime-suet
are sugar cane, coffee, and among the
/ Innnmna aRnh.ta llxrEt ntha,
] IRONS are more or less indifferent-thu,
maize and sorghum thrive in washed
out soils containing a minimum of lime
"The absorbent power of the soil ii
important, Woltmann says, "and THU
gives emphasis to the high value of the
studies on the absorptive capacity OF
daweiian soils by Kelly and McGeorg,
V the Hawaii experiment station.
Nitrogen From the Air
"Tbe characteristic red and yellow
soils of the tropics possess remark
able power of absorbing ammoniaca
nitrogen. This must be of imme nse i'm
pOrtance, for the rainfall in the TROPICS
is abundantly rich in nitrogen; thus
yearly rainfall of I20 inches bring
Town about scventy-two pounds of nj
trogen to the acre. 49,,
LAS for the use. Of manures, the idei
that tropical soils are inexhaustibIe il
now exploded. On the contrary the,
are easily exhausted. In such case
they are hanured or, left fpllow. o
abandoned for new lands. Which o
these methods is to be followed de
ponds on the cost of fertilizers an,
economic conditions Fertilizer in
| NrinlI5 asI l.. 7
may injurc quality but it keeps tn
plants healthier.
Extends Life Of Plantation
"The most important effect of ma
nurrS,' Woltmann states. els that o
pr"longing the duration of plantations
While coconut palms live usually abou
seventy years, the use Of manures pre-
longs their productive life to eight
and 100 years. With coffee also, suit
able and early manuring may proIon
The life Of the plantation by five or te
years.
"Grcater care is needed in the sclcc
ton Of manures in the tropics than i
temperate zone agriculture. Thus o
moist and highly ferruginous soils,
deficiency of Phosphorie acid is hardl
TO be feared. Potash salts mostly civ
good results in regions of abundan
rains, whilst potash abounds in ari
belts. Tn general, heterogeneous manure
are not to be recommended in til
tropics as they are in the temporal
zones. Lastly, when lining is require
It must be done under the form q
limestone, or coral sand. quic Kline b,
ing rather too energetic in tropics
soils
"Tn general" Woltmann saw
"tropical planters and farmers mus
prefer tn" less easily soluble manure
TO the more soluble ones, especially i
regions having high rainfall. THU
Sulphntc of ammonia and Peruviu
gunno are TO be preferred to nitrate {
soda. and bon" meal to supcrpHosphat
the soluble phosphoric acid Of while
ro"iAlv rCtrogradcs in red and yrllo
soils. -
--S$S