The Hawaiian gazette. [volume] (Honolulu [Oahu, Hawaii]) 1865-1918, 1901-03-29
SOIL. AND
PRODUCTS

of a bulletin prepared by Walter Max
we'll director and chief chemist of the
Hawaiian experiment station, and issued
by authority of the Secretary of Asricul-
ture Mr. Maxwell discusses the climat-
&c, soil and other conditions as affecting
irrigation in Hawaii and gives the re-
suits of experiments carried on by him
for d number Of years. He brings out
SOME Of the most interesting phases OF
irrigation problems in that Territory,
and lays basis for further investiga-
lions OF this subject there.
The precipitation of atmospheric mois-
ture," writes MIR. Maxwell lis very UNI
even and irregular over the surface OF
the earth. There are zones that are
marked by annual deluges, and there are
vast areas upon which rain rarely falls.
These rainlcss areas are not confined 10
conditions peculiar to specific latltudes,
but are found in the tropical regions OF
India and Africa, over the wide plateaus
of North America and in other LOCALITIES
having widely varying climatic cohulN
tons.
'''The regions of small rainfall are very
generally distinguished by lands of great
natural fertility. This is due largely, on
the one hand. to the absence OF great
rains that leach out the elements that
feed plants. and, on the other, TO ftne
relative absence of crops, which resulta
from lack of rain. Among the most prot
d,ictiye tracts upon the earth today are
regions that We're naturally ara, Dut
which have been rendered productive by
irrigation. These tracts include the Pun
lab and other vast districts of india the
great basin of the Nile in Africa, and
NJ arid
Gently been brought under cultivation In
the middle and western United States.
LACK OF RAINFALL !
The failure Of the natural rainfall to-
produce crops may be due to the INSULT,
cheney of the total precipitation, as in,
regions in India, Africa and other lands,l
where 1t does not aggregate ten inches.
per year; or it may be due to the sea :
sonaI distribution, as in other parts Of
India and Africa, III northern queens
land and some of the Pacific islands.
where a heavy and almost the whole
precipitation takes place within two or
three months
I'm some localities in northern Queens
land the annual rainfall reaches and ex-
ceeds 100 inches, yet the sugar cane crop
has to lnger through an annual arid pc
riod which greatly reduces the yield,
while upon the Pacific Islands of Ha-
wall despite the winter rains many of
the most fertile lands would be useless
without the prevailing practice of irriga-
ton. Irrigation, consequently is playing
an increasingly important part in mod
ern intensive agriculture.
1.-THE history of irrigation covers meth
DDS of applying water to crops including
the Crudest efforts of the peasant and
the great systems executed by govern
ments or corporations such "a are in
operation in Inua, the United States and
in the valley of the Nile. Certain OF
those systems are vast, and have been
instituted under the pressure of meeting
great emergencies. Today India is using
irrigation upo stupendous scale in
graphing with the calamity OF famine.
Economic irrigation requires the con-
sderation of physical laws which were
unknown to the authors OF primitive
methods. and which have not been gen.
orally observed In establishing the huge
systems of irrigation already mentioned"
APPLICATION OF WATER TO CROPS.
In discussing some of the physical laws
which underlie the application of water
to crops and the evaporation Of moist
ure from water and soil surfaces. Mr.,
Maxwell says:
THE movement OF moisture is con-
stantly going on. The simplest evidence
Of this movement is seen in rainfall and
in the evaporation from water and soil
surfaces
THE factors that have been given the
greatest prominence as exercising a con-
trolling action upon evaporation from
soil and from the surface OF water are
the temperature and the relative humid
ity OF the air. This view is amply sus-
tanned II the examination is confined to
the action OF these factors during the
extreme seasons OF the year. There IL
no question concerning the greater evap-
Grafton of moisture from soils and wa
tiers Turing the months OF summer. when I
temperatures are high, and the amount
OF atmospheric moisture is also rela- !
lively small as compared with the beha-
vior Of these factors In the cold |
season. This Is demonstrated in many
localities by the excess OF water that ac-
cumulates within and upon the soil In
winter. and the droughts that obtain in
the summer. There are localities and
regions, however that are so fortunate
as to have the greatest rainfall during
the season OF greatest evaporation and
consequently Of greatest plant growth. !
Setting aside the differences concurrent !
with the seasons and combining observa- |
lions to the relative actions OF the sew
eral factors during TIC months Of sum
mer, II Is then found that the tempera-
ture Of the air md the amount NJ moist !
ure that II contains are not the most
dominant factors I'm the control or evan
GRAFTON. AS already said. they are fac Z
tors, hut their combined effects do not |
conNuare with the effects OF wind Not !
only IN the matter Of irrigation hut al :
so In the location and exposure OF res /
"rvoir7 this fact Is of leading lmpor, /
tance"
RESULT OF ENPERIM
The bulletin contains an account Of n
series ~ evaporation experiments Under
The heading Transportation Of Moisture
by Vegetation" the bulletin recites;
1.-THE volume ~ water oyaporated from
the s0ll ana the volume transnlred by =
the plant during ~ growth are the con-
trailing factors IN determining the total
water required IN the production NJ n
cr0n. and therefore mo quantity NJ wa
ter IN h0 supplied by IRRIGATION
"Wltcr outers very larPrlv into tho
structure NJ am living organisms IL Il
NOT only mo AGENT which makes possible