Effect of fertilizers on the physical properties of Hawaiian soils

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7' ASSIRM.TURA W-ERT STA TI*V'+vj
M WESTGATI Aist in Charge,

Bullet o 38,.




OF FERTILIM" ON THE PHYSICAL,

PERlTIES .OF: W AIIAN SOILS.






w ILLIJAM. MCGORGEY
Assistant C emit.






UNDERn THE SUBMN exOF
OFFICE OP ME.W BTATIONS9





G. & DEPARTMENT =O==v .




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[Under the supervision of A. C.. TaE, Director of the Office ao Experiment Statiia:
Department of Agrioultmue. 1i

WALTER H. EvANs, Chief of Division of Insular Statons, Offie of Ersparm


STATION STAFF.


J. M. WESTGATE, Agronomist in Charge.
J. EDGAR HIGGorI, Horticulturist.
D. T. FULLAWAY, Entomologist.
Wnm u. McGEORGE, Assistant Chmit.
ALICE R. THOMPSON, Assistant Chemist.
V. S. HOLT, Assistant Horticulturist.
C. A. SAH, Assistant in Agronomy.
F. A. CLOWEs, Superintendent of Hawaii Substations.


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LETT ER OF T-RANSMITTAL.


HoIRoway, H&wmn, Aigust 1, 1914.
rethe honor to submit herewith and. recommend for
As bflletin No. 38 of the Hawaii Agricultural Experiment
dealing with the Effect of Fertilizers on the Physical
H *awaia Soils, by William McGeorge, assistant chemist
tion.The pecubar constitution of Hawsaiian soils makes a
be pysicl -roperties of theme soils one of unusual ipr
'this paper therer are ,described-'systematic experimnts
Aet~rmine the effect of various fertilizers upon capillarity,
Oocculstion, cohesion, apparent specific gravity, vapor.
MIhygroscopic, moisture., Before it is8 possible to reach
Okndxerstnding of Hawaiian soils it has been found neces-
atWady them from 0l standpoints. The paper is- a contribu-
tho knowledge of the physical properties of soils and particu-
'the effect of fertilizers in other ways than as plant food.'

E. V. WrHcox,
Special Agent in Charge.
.A. C. Tutm,
Mrector 0 'cc of Expe'Yrfient Stations
UT.S. Departmtept of A4griculture, Washington, D. 0.
Pobbication recommended.
SA. C. T BE, Dir,07
Publication authorized.
Do F. HoveroN,-
Secemlary of Agric~umtr.
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ILLUSTRATIONS.


.........

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Relative apillprity following addition of salts in equal quantity and in

molecular proportions............................................

Effect of eats and fertilizers on capillary rise of moisture .............

Relation between cohesion, apparent specific gravity, and moisture

content of soils,.-........-..........................................


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OF FETIIERS N H )JS
ROPERTIESOFf HAWIA !30ILS.



1een the customn in Hawaii 4aiep agrclure was first placed,
4ounecil-basis to stimulate crops wihheavy applications
Jo fetii`rs. This procedure ha~s bee mai ie in. spite
"c ht a majority of the. soils wre natrlly well supplied with
od, in some instances abnormally so.
"soils axe of such a nature that the mantenance of the best
0hysical state 13 imperative, 'Ihev x derived from the
S of basaltic lava! have smice baimpregnated with
ppstnein many of the lowlands -and wih large amounts of
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% noWter inthe uplands, where the ranall ihghand the3
onprofuse. Bein-g derived from highly bsic rocks, the result-
waisae highly basic in composition. Th silica content varies
15 to 50 per cent, while the basic constiuets, iron and alumi-
oompose the major part of the remainer The tendency of
mwetal to form hydrates or silicates, terinfluec upon the
MIstrgture, draiae climatic condiions, temperature,
nand above all, the effect upon the moistre supply, are mat-
*hich demand the'-careful consideration ofariculturists in these

'SWi moisture is 4 prime factor in successful plnt growth. It not
4*l infl:Lencea the physical condition but als acts as a vehicle for
41 rnsiso of plant: food from the soil tote plant. Since all
minraland -many organic substances are mor or less soluble in
jstaMr and. since all dissolved material is knov to affect the physical
esof the solvent, it may be concludd tat the properties of
iture and also the physical condition of te soil are partially
detupon the composition of the soil soltin.
These physical properties include capillarity percolation, floccula-
ncohesion,- apparent specific. grvity, vapo pressure, and hygro-
adopi Moisture. Alhuhthe laboratory, deminations of thewe
proertesof a soil and of the effect of salt Aereon have little
diea*practical value, mince the eoil in suh cssis not in a natural
eta*e n other conditions are abnormal, thymay be useful for
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In view of the above facts, this station has devotedcons
time to investigations upon the physical properties of .soflsi
function of fertilizers, other than as a source of p< ..ooi
special reference to the movement of soil moisture. It
erally conceded that no simple explanation of the influence e
zers upon the soil or the plant is possible.

SOIL TYPES.

As in previous investigations upon soils in this laboratory,
widely differing chemical and physical characteristics wereii
The following tables show the physical composition and pi
of these types. In Table I will be found the mechanical eolmtt
as determined by sedimentation according to Hall.
.. :. ....
TABLE I.-Mechanical analyse of the soils....
Soil No. Moisture. Volatile Fine Coarse Fine St. ni k it:l.
matter, gravel, sand. sand.

Per cent. Per cent. Per cent. Per cent. Peren. Per n e. Per cet. ~ Per
428................. 13.80 25.65 11.89 28.26 13.63 4.64 1.L I
448.................. 12.45 28.83 1.70 7.52 14.29 11.75 17.4
516 .................. 10.41 17.64 3.40 5.29 29.66 10.30 1.
530...........-...... 3.58 13.90 0.49 5.76 10.34 7
542................... 7.98 17.81 .81 31.26 13.39 17.79
573...............- 12.26 20.44 1.50 31.48 19.10 11.9 3
574................... 7.60 13.96 .36 1.15 8.07 9.35 24.90
S-.......
Of the above soil No. 428 is a dark-colored, highly organic, i,
soil from Glenwood, Olaa, Hawaii.
Soil No. 448 is a yellow silty sand from Hilo, Hawaii.
Soil No. 516 is a sample of manganiferous soil from the W j
district, Oahu. It has a chocolate-brown color, silty, texture,,:
maintains an excellent mechanical condition.
Soils Nos. 530 and 574 are samples of red-clay soils, the forezi
a light and the latter of a dark red color. ;
Soil No. 542 is a titaniferous soil of grayish red color and
texture. Its physical condition is very similar to that of soil NRo,,
Soil No. 573 is a "dust" soil from the island of Hawaii. ...
dark-colored, highly organic silt, and very productive.. .
The Soil. London, 1908,2. ed., p. 51.















t~ V 04" Oi owf euitre





Pameqntage of Wate
ter to, saturate.
sP.,

Weigh. Volume Weit Volume*

Gw e.-Perfetwi Per cent. P Per cent.-PTM
...................... 1I0 177 61.1 51.8 648 5.1
..... 1i 6 0.2 53.7 O 457.5:
........... 150, 06 66.3 X6.5 7. 61.0
-1--------------- 132M 43.7 49.6 48. 1.S 7
-------. ------16 61.7 67.8 63759.7
-------- ....... 150)191. 60.7 76360.7
---------------0.161 50.3 46.9 26 58.3


SPECIFIld GRAYITY.

at* given tho Spedific gravities, -both real and parent,
6oMpaative volume occupied by 10 grams of these
la ,ixiterstitijalL Spaces.' as determined upon teair-dry

AntsA III.-S8pecific gravity and volume of -the soils.


6j*WOWUPO(L Sonl No1. spoitic Apcp Vocupid
gravy. gaiy. gravity. gravity.

.. .. 2,482* 0. 8474 4.0 542 ....... ......... 218784 097 3.48
......... 2.5W64 .8M2 3.96 573 ----------------- 2.4454 .73 4.09
,s.... .85( .82 .5a 574 ----............. 2.9087 .9316
....... 2.9M 1$06 3.40


foegin4dt, while: of more or less empirical nature indicate
vari inp physical -rprisof Hawaiian types ofsil. The
khow tL hgest. Specific gravity, both real and apparet,: the
sit iltis next, while the. sandy soils show the lowes. The
to,,laton exists with regard to the volume 'and water c city.
CAELAR HOE T.


4"eCSpillairy movement of water more than upon an other
4ris the, p at dependent for successful growth The
"I espillaFy water are many and involve the tra --isan
a7 s I n n n a + a u i a + a A n o e a n t + .. s



































I----O LEU lR PROPOOVIffS
0EQUAL WE/6HTS .. .. i




FIG. 1.-Relative capillarity following addition of salts In equal quantity and in molecularpi

When an object is removed from an immersion in water it re.
a thin film upon its surface through the property of surffee tetM
In the same manner the soil particles are surrounded by a'liiS.
elastic membrane of water under a high pressure, the thickness i
ing within certain limits with the moisture content of the soil.'
water is lost at the surface by evaporation or around the roo~ 'l:t
absorption, there is a movement of water in the direction of6": i
creased tension, thereby tending to maintain an equal distribution j
water. On the other hand, viscosity, acting in an opposite nahi
from surface tension, tends to retard the movement of water. '
Water in soils is never pure, and all dissolved substances fBifeti
degree of surface tension and viscosity of the solvent. Praofi:' J



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8tiio uon. te uraceteniono s
is ~ 11 0* b oserbylsthand. ifue oaer ThU t



domain'b isopl In vaisg the, 0co"in to the mecAni
itubs Eperi en s than pure water on wth Isoils
hdito suiimsn n alnto thecertainy o the rpelation, of tm

tures were uae, sinldisng everaly mesrgeni manures As a
dde rin' Mout propoil colunalthougheir moeuay taeighace
thie3a n variesio inet heighti towhc the w'te woud i al
raeste patswresn stdye of, small amouty-~s.cv oti
oreprsentibtes. dE aotiedi experiments were mad noof
hisiica shond iTabld kaoin toicertain 'thue wrelobtioned:
terowlsn tho soils Ioun toandli about 40sltnertilfizer of ateria
ture usd, digseeal.sai.m~
"Of ~ ma I.-Caillary thriet-o hse ofsalts, icthom aisos. wr.md
808ade Non amr ous ounts. proportionals Ias.ds. their days dlays weighs. as

th e vaitOt in heigh to. whch.c th wate wo uld rise. as-
e...amounts o16f81 4.94. 4th0 50l.4ayi from 03.0 6 58.462.16Per cen.5



toe hiklyorgnwsly olso the reeateve capillary actviteo thesol*i u-
ela sis leshonn alI, which the figureois were ioteradined
In filling the ubsoi coluneesr to stercid inaotonie-hablf Mchwatrei

A loE wie it lopo te n int the soils. wihdaw
0o
&AN. 6 24 4 6 1 19- 3 7
bous. bo .hus asdy." as as as as as as as
OO m 7.C.C.C.o.C. C. C.
..... 2. 65 4.9 4. 7i.1 .40 04 6. 0s 8.
224 2. 44 4.0 4. 25 4. 4. 67 5. 5. .... 7.
..... 3- 29 4. 90 5.4 5. 39 5. & 21 6.
-------- 3-95. 73 6. 46 6. 7, 06 7. 93 8. 98 I
....m S 78 5. 2. 40 6.0 6. 92 7. 64-48 9. W
...... 10 M 42 6'0 7. 16 35 8 4 9. 0. 198 11. ...
337 4. 40 4. 51 4. 4. &15. ---- 6.
To fcoun
T~ ighl oranicsilt so shoed he geatet cpillry ise h
d! silleswietesnysiswrinemda.
"I h ue ti e7sr o xriecnieal aei
.rd, t banauiommxue hsi aepsil yPo
jotn ogwreWt opo teedit h tb n ihrw
-o twt rtr oin
A ,D et g. ade mBL4(Wt I


















were aaaeu m equal amuuntn t nt mm IU .tiu a pr pr
No. 530. The former rate was 0.5 gram of basic Mx i
of soil and the latter as follows: Calcium carbonatte with
weight of approximately 100, was chosen a aa stand
at the rate of 0.1 per cent, the other salts in greit" Or
in proportion to their molecular weights. J
From these curves it appears that as a whole the g
of a given salt is to affect the soil similarly whether :ad9~
weights or in molecular proportions. This is at least t
capillary activity. The curves throughout are very gilar Mt
cate that an increase in .the concentration of the alt res
diminished capillary activity.
This variation in activity as affected by increasing the
tion of the salt suggested a further study of the phenomesri n,
results of which are given in Table V. Three types of soil and a -
sand were used and the amount of alt used varied from noneito :'i "I
grams per 150 grams of soil.

TABLE V.-Capillary rise as affected by increase in percentage fsIalt added. ,
~:'g --, ',, ": .:ilj; : ,',

Percentage of salt added. .i ,,Ji:

Salts. Soil No. 530. Soil No. 448. .
-------------- ...:-.... .':,i:' ..i ..: !
0.00 0.06 0.16 0.33 0.66 3.33 6.66 0.00 0.06 0.16 0.33 0.66 3.33

Cm. Cm. Cm. Cm. Cm. Cm. Cm. Cm. Cm. m.. Cm. Cm. C .
CaO.......... 37.3 34.1 33.2 32.2 33.5 18.7 12.5 30 35.0 36.5 36.0 37.0 3 .t.
NaNOs....... 37.3 34.0 33.0 31.4 31.5 28.0 26.2 30 35.9 37.5 36.0 36.0 34! .
(NH4)s 04.... 37.3 31.9 31.8 28.6 25.5 21.1 21.4 30 37.6 35.3 36.0 34.2 316. .
CaS04........ 34.0 29.8 29.3 29.6 28.5 29 8 33.4 30 34.2 34.0 34.4 .33.2 34,9
CaH(PO4)..... 37.3 35.5 37.8 37.2 38.8 32.7 23.3 30 34.6 35.4 34.9 37.0 83.3
CaCOs........ 37.3 35.4 33.0 31.8 33.8 35.3 38.0 30 33.3 32.7 32.2 34.1 35.9
KaPO........ 34.0 31.0 29.0 25.9 26.0 21.7 13.9 30 34.9 33.6 33.0 31.4 31.1 :.i:;
KCI.......... 34.0 28.7 27.8 29.0 28.0 26.5 26.0 30 34.2 35.0 34.4 35.0 36.32
MgSO,........ 37.3 32.5 30.6 27.9 27.2 21.9 21.7 30 33.1 38.0 34.8 35.8 31.4
NHI4C........ 37.3 31.8 30.1 30.5 29.2 26.4 28.2 30 34.2 34.2 33.2 35.8 34.5
Na3COa....... 37.3 28.4 24.3 21.4 18.7 9.4 6.9 30 32.6 33.1 30.1 29.5 17.4 14.
KaSOs........ 37.3 32.3 31.8 30.0 28.2 26.0 25.8 30 36.4 36.9 36.4 34.8 31.5 831i
alts. Soil No. 48. :........a s..
s j .. .." ...4:: :: ..
salts.". ..S ... -N.48;::sn
Salt. S il o. 28.Sfleasnd..': ,' ,,;*;, '


CaO.......... 29.0 37.0 36.1 38.0 40.0 83.2 26.2 98 7.3 6.4 6.9 7.0 a0.0
NaNO........ 29.0 38.0 38.0 37.4 38.0 35.5 34.8 9.8 10.9 12.4 13.7 13.7 12.1
(NEH)SO4 .... 29.0 37.9 34.9 34.6 35.0 33.5 29.4 9.8 12.2 12.6 12.6 12.6 12.3
CaSOi ........ 29.0 37.0 38.0 35.3 38.4 38.8 41.2 10.2 12. 1 6.7 13.0 14.5 22.2
CaH(PO)..... 29.0 38.6 36. 5 39.0 40.0 38.2 34.1 10.2 13.9 16.8 15.3 14.4, 14.5
CaCO ........ 29.0 37.7 38.0 35.2 36.3 38.9 37.6 10.2 16.6 14.9 18.3 20.5 27.4
KsPO4........ 29.0 38.8 37.9 37.0. 36.5 33.1 24.2 10.2 12.4 14.6 16.6 15.7 11.6
KCL.......... 28.6 36.8 36.8 36.6 36.9 37.1 35.2 9.8 10.9 13.5 11.9 12.4 14.1
MgSO4........ 30.7 43.2 42.9 42.1 42.8 40.0 36.1 9.8 13.9 16.5 13.8 13.7 13.7
NH BC........ 30.7 41.4 41.5 41.2 40.8 37.0 34.9 9.8 11.2 18.3 12.3 11.9 10.9
NaCOi....... 30.7 36.8 37.7 36.1 39.0 34.4 25.4 9.8 15.9 16.4 14.7 15.7 17.5
KsSOi........ 29.0 37.2 35.7 34.7 35.2 35.2 35.0 9.8 13.7 14.1 14.5 13.9 13.0


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!iNo. sQ.-The tible sho, dt, *sl the salts, wit
exception of calduta phosphgte, caus a,renklr dearease
of msture "withineaeicocnrio.Glinph-
when added at the rate of 0.46 per ca, ien cres the
.tiI

J et (m a4i No. 448.-Hereagi the effects. of various salts Seem
Related with, few exceptions and the tendency is toward an in-
SIn capillarity up to a: certain concentration beyond which a
addition of the salt materially retards the rise of water.
Ain to this mule are sulphate. and -carbonate. of calcium,
being difficultly soluble, would materially change the physical
of the- soil,. and calcium phosphate, which, being a soluble
exerts a chemical. effect.
et'f on aW.il No. 428.-The effects of salts. upon the capillary
mt i this soil are. similar to those. in the former except that the
in moisture. rise is greater. The soil, containing a greater
A.-ageoand, shows a higher rise in moisture.
eton silica xand.-Con..ditions, in sand axe ideal -for measuring
effect of- S, &ts upon capillary action within certain limits, beyond
any further concentration gives misleading results. ,This is
deto the filling of the pore spaces and the subsequent drawing up
moisture, caused by, the salts as they become dissolved by the
rising moisture, rather than to the action of the salt upon the activity
of the film surrounds the grains. Taken as a whole the results
with a concentration of salt. below 3.3 Per cent axe very similar to
those obtained with the sandy soil, the more marked variation being
in the action of lime.
Apparently the most important inference to be drawn from the
foregoing table is that the action of a high concentration of a salt in
imogt instances only magnifies that of a small application.
With this fact determined it was decided that the 'salts Ishould be
Used in as small amounts as possible and in amounts proportional to
their molecular weights, thus more nearly approaching normal con.
edition. The same molecular proportions as previously mentioned
were used, while the fertilizing substances, such as mineral, phos..
phates, blood, etc., were added at the rate of 0.1 per cent. The
tans i4a in Tabhle VT show the relation of various salts to the rise
ofmitr eea o h oiaigtpe fHwia oa









































MAs 04


NH4


PHbS ROCK-


BLOOD+ ACrD POS.

8tdOlo SUPERPnMS.


21ff1~b/2-2--


a ltn,-s- ---- I Le I -

fPi. .-Iffeot of salta and fertilizers on capillary ier of moIstue.


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.111 on. i 5 4 3. 8 OW, 804 24R 14




.58 4ve 8 U. 7, 5M.0 F 1S '39. 0- 36.4 '23. 6 15. t
4. 340 55.3 S9 4. 37.1 25.4 1&.
4. 3 35.0 55.72 3 36 30.84 368. 21. 9 14. 6
.2 7.6 31.1 54,2 34.1 364.7 347. 23,3 1,
..... 4 -28, 30.2 $54.9 9.5 39.3 33,5 23.6 16F0
4847.6 35,09 06.1 36,9 40.7 37A0 %,.7 10.8
2 4 64.3 33.4 56,2 38.3 41.4 '38.3 21.9 18.9
AOp 44.63 1 34- 560 :58 -7 41.97 37.6 : 25.2 12.80
46 45.2 36.9 55.,5 S4.54 03.4 39.2 25.6 21.0
....... 1209 6. 5 34-9 5. 55.1 36.2 4 0A. 37.01 24.7 1-4.7
......? 47. 31.9. 54.2 MS 40. o3.4 e 0 20 25. 10.5
------ 701 44.3 1,3 55.8 ,37.7L 40.7 37.0 26 5 12&7
-------- 7 45.4 3.5 54.02 33.4 38.1O 4084640 j3 2. j 21-1
,........ 1 46.5 3528 54.5 .36.4 41.3 37.1 23.6 16,7
... .... ...... .720 45.9 293. 7' 54.79 30.0 36.9 Sq3. 5 5.O 15
ht... .. .. .21 465 3 7.2 54.4 34.7 40.0 36.0 25L7 1,8.7
................ .17 45.8 34.0 5&. 7 38.0 2 40.4 40 .3 221140
spo ........ 11. 4-9: 31S7 54.7 337A 41,7 -39.1 .--- 1.
1___- 42 7 4 4 5 1 4 .3 257. 0 1
Mi .26 40.01 31. 0 55.2. 376. 425 1 0 37. 2.1. 6 14.:5
(gd spr a.ht...... 1A 47.*,4 36. 54.1 4 4,2,0 0 9 6 14.48
-------- .... 2D 45.4 33.9 5,4.0 34.5 40.2 39.5 26.0 15.1
------------- .2o 47.59 37.4 W4 2 35.2 46.5 403.0 25.75 15.82
k......... .... -20 46.$ 37.0 54.4 3.5- 42.3 40.1 26.3 11.8
ps,' ...,..... .2D 4761 7 345 7 5.6 0' 6 4.2.0 3 94.9 ------- 15.0
------------... .20 446. 31.4 U6.9 8 3.37.1 4317. 4... 26.6 14.1
11.... ..... 20 47.6 34.8 54,2 357.5 41.7 0.3... 27.4 11.7
.. ..... .20 47.61 34.0 95.5 36.2 42.5 4.7... 21.6 142.
--0 ........ .20 47.4, 36.8 54.5 34-9 40. 9 3.0... 26.4. 13.8
------:..;... .20 -47-9 32.8 5 & 4. 36.0 41.8 37.4 26.7 12 1
4 A2-...._, 90.4. .20 47.9 3544 560 35,1 40.7 -39.8 26.5 142.
-------------- -20 46-8 & 3 56.0 37.1 40.8 7 5 26.8 14.1
.. 20 47,... .5 34.3 55.8 17.5 42.0 ------ 25.5 12.2
------- .2-3 3. .6 M.9 409... .......24 624881 262
14pl nie (i 26.6niu 1up3e.9hshri cd adptshi h





on rMic f snd, Here (in 8 ois~ psuilpae) phsporeplacidand potsh in the


tc by appyingcre(i.2 lutae theknw effects of slsuo the fertilizers


otfare t- clim orid cland thangh. tbe
VEpd on soile Nsad.-Ie it8 isd Possible tohexepoin mosrte of rihe
tostbyre Is qit rait knrown dereaigtaveylo rieia
ofme t. irsl,~t..Iorganicsatinrse and organic sub-tne de rdcda
nreardthrie of cwilarter iThihetielitofth epri


det Thse quite rapid at coirst, textreas'contoi a hihverycelwtrge inf





















diminished capillarity. .
Effect on soil No. 530.-The physical character of this t sp
is such that chemical agents would be expected.to. mate.t.i
its texture. This theory is borne ,out i the. diminishe;&O
activity noted in every instance. "
Effect on kaolin.-The diminished capillarity observed inm
of the effect of salts on kaolin shows a direct -relation J
this substance and clay soils.
Any attempt at classification of the above restilts
theoretic considerations only indicates the complexity o
any one theory to soils. More than one factor evidently
play to which it is necessary to give due. consideration.
tilizers do markedly affect capillarity is clearly shown.
mixed fertilizers there is little variation in rise as related to v
in mixture. Those in which nitrates are used show decrease in-
rise as compared with those containing ammonium sulph..atl4, i..

EFFECT OF BASICITY ON CAPILLARITY. ,.
:... ... .: .
Organic manures, as compared with the salts, retar thlt ris
sandy soils and decrease the rise in others. As a rule, ma.
salts affect capillarity less than the calcium salts, potassium
than ammonium, sodium less than potassium, and the mon
salts in most instances less than the dibasic. Among thebs
salts, carbonates and phosphates show the lowest, silp.ates:
nitrates next, and chlorids the highest water line. ,.
With the phosphates the rise of moisture seems to depend. up
acidity or basicity of the salt. This may be observed by com
data in Table VII with those in Table VI under the phospla|
lime. Here also the relation between acidity and rise of moist
similar to that observed in the case of the potash salt. ,

.,... ...... i




A ....:. A.
a M.'i, "'ii-







t-J -4I
4





oRqvalet to O.5 pr cet KIO.
drlabesalts, Phosphates and carbozates of the
lie owst, water toble However, they Are m uch more
icsoils de. to their solvent actio or chemical reaction
matter Present. These, hydrolvzable salts alto mause
f the, clay particles which, in Hawaiian soils, are partly
9tiron and tlmiu hydrates and'are, conducive to the
sa~to, thus closing the pores, increasing friction, and lowering
4f maistare rise.


which. passes -Wlow- the- surface, in excess of that held
400avyaction or surf ce. tension, is subject to the laws of
rate of movement, oevr is dependent -upon vari .ous
su ech as the size and composition of the. soil particles, height
itwaface above water table, surface tension, and -viscosity of
8hilsoltion.
M ti' MIs qtegnrlyheld to be Most, rapidmin soils in
Mcapila~ry activity is greatest, decrfeasing with height -of column,
Js 4ster iin wet soils than in. drIn y soils. -Clay, of course, offers the
physc~esstace to the passage of water. and the resistance
hewith -the: degree'of .aggregation of the clay. particles.
m at with'which water will pass downward, then, depends upon
State bf the soil and this in turn varies with the arrange-
of he oilparticleso. Both of these proprteowvr e
by the nature of the soil solution, percolation decreasing
ifincrease In concentration.
vrosidying the. effect of fertilizers upon this property of soils
IiW gls tubes. lotiing soil colmns of about 30 centimeters
e-ktte up as in. studying the capilary activity. Thewe tubes
p~cnnetdwiha. coA tn supply reservoir which maintained
ahOIheAado water in the tubes, and the water passi Png through
11l11 ra mfonarewa interveAla The totals of these mewur6-,
wa a
gie n al





































Superphosphate.........
Slag....................
Phosphate rock..........
Cottonseed meal.........
Blood...... .........
Blood and acid phos-
phate..--...........---
Blank................
Blood and potassium
sulphate..............


Oc.
1,688
4,784
1,990
2,432
1,892
1,4764
5,865
4,753


Ca.
1,940
1,588
1,675
1,443
1,456
1,567
1,710
1,423


CC.
2,568
3,256
2,546
1,924
4,027
2,012
11,956
3,5241


a.
1,581
3,632
3,9002
4,659
3,56
3,324
S7,26
1,715


Potasim slphate and
acidho ........
2(N H0-- a............
4 -Aip-1-0 sa.........
4.5 NH4)-23- s...... ...
2.0)-14-2-............
Acid phosphate.........


af.
3,491
2,305
2,763

3,Sitil
3,04
aim


1 ,
a.
i i


"3 m


1 Stopped after 21 days.
SStopped after 2 days.
a Fertilizer mixtures supplying nitrogen (in ammonium sulphate), phosphoric acid, ain4
order and proportions (percentages) given.
4 Fertilizer mixture similar to those referred to in footnote 3 except that nitiroen w.asO
sodium nitrate.

A glance at this table clearly indicates the complexity : t tbC1e
of the passage of water through soils. It is quite generally
that those soils in which capillary activity is greatest offer S.i0
resistance to the passage of water. Soil No. 573 fails to lI
port to this theory, as does also No. 516. In these soils the c
activity is greatest, while they offer much greater resistance 'i
passage of water than the sandy soils. Even the heavy I
offers less resistance than No. 573. .
As a whole the calcium salts cause less resistance than m
salts, ammonium less than potassium, chlorids less than sUi
clay soils, but the sulphates least in organic soils. MixturesM in ':
sodium nitrate is used cause less resistance to flow of water
where ammonium salts were used.
Soil No. 530.-All the salts and fertilizers added to this t.
retarded the percolation of water. There is a slight relation b
the degree of resistance and the flocculating power of the salts.
rule the most deflocculated samples were among those that
the greatest resistance and vice versa, as was found by .


;,; ;i
.
1


....... .,. ... ..
..... .. .. ..
;....
...: .; .. ; :...
... ."
...'L' "j."EE.
...." ..:d .
.. ..* -:. ...:.:...': .* .../
"... ... "i: "
....!" .:" .. ":t i::"* :*" "* "
".. '".;, ,.I" ii.;, .. : .
'; .'";i


.. ..










twke As I' ter il
4 ONW& ea io day to &ay WKte VteMala
throgh't the col n h lay beg=n to, swe8.
nl;,to soilx~a& 580 amd 573.
Pap-litreath n i truh this soil vwai very low aad
acivity;sak had, very uittie effect upoanit,
itatt& passing' trough, the tabes was les on the last
igatient tan on the fist day. There is Practically no
in: t it eso that the action, of the salts is probably
Mynic matter.' Thim soil is the only one in which any salt
terite of flow., These salts wIre calciim .sulphate,
Mooi and superphosphate. Sodium. nitrate strongly

Y44 .4n, thia instance -it: was-nov-possible with the equip-
leto maintain a constant head of water, due td. the large
bihwould peicolate during the night. All the materials
4h ecesesed the rate of. percolation but the daiy rate.
d Ou








stead4, for which reason the series was not camre, ou 0's
y s nthe two previous soils., This increase was probably
kv, asigout4o the sublstances added. The action of sodium
and sodkim nitrate was very. similar and. unlike the effects
'above, organic, soil. -The organic manures resist percolation
attogly.The, calium. and magnesium salts offer -the greatest
sodium salts next.. a oium salts next, and potash salts

15. 16,7-This soil, owing to its mechanical condition and
donenioffer little resistance to percolation of water.
Geo; o adingany agent is to decrease the flow. However, the
obtained indicate that. some soils are capable of restoring their
sis shwn y the fact that the depression of the first
bAecame less as ddif~sion became more complete. The dibasik
effeo low.. resistance- to percolation, than the monobasc

FLOOCWULATION.
rb ile of flocculation. in soils i's one of considerable importance
as9udy of :soils such SA occur in these islands. The red clay ]a a
tiepossessmig an. unusual tenacity and requires judicious handln
prevent puddling. xnd to mananthe colloidal clay in the best
Condition, Tarious investigators, recognizing that a solu-
maIt W.ill bring about the anlocuaition of t.he supndedsar material
!I|~ "hvesuidterdtw:t h





















W11t IjUJJA3LUSLIL L0 id VLAL3D VULWb MO DUU.Ji UAU IVDiJtULJL UUILULAL0alRLI5U4l
the formation of a -colloidal state a'nd- the tellatio*v fa
state may be of considerable local application...
As a means- of studying this property of Hnaw-aian. cia
of highly puddled soil was chosen, one in which tba: -ai
remain in suspension for weeks. A stock 8sunpemnwmoa 't '
sufficient for all experiments was prepared, so that a se
known concentration would be available. 'The, degree 4i.l,...
tion, to a certain extent, depends upon the relation of the
clay in suspension to the strength of the flocculating ageaik ON
Normal solutions were prepared of all the salts used sf
experiments, except the slightly soluble ones, in which case
solutions were made. By a series of preliminary experinea*
salts having a negative or deflocculating effect were- e
These include potassium and sodium phosphates and c
Secondly, salts causing a flocculation of the clay but not
soluble to form a normal solution were eliminated. These e-I
the oxid, carbonate and sulphate of calcium and ithe :Oid 4
bonate of magnesium.
The comparisons were made in glass cylinders of. 400
meters capacity in which were placed 2 cubic centimeters o
salt solution, 10 cubic centimeters of clay suspension, and i
centimeters of water, making a total of 200 cubiq centimeter. i
mixture was shaken and allowed to settle. In the case of the sr
flocculants this proved too great a concentration, hence the
ments were repeated with a much weaker solution. The r
given in Table IX.

.. ..r. ... .





















Sageo certain extent with the findings of other
ti ,T ey a relationship between, the valency of
w.'g pour. The most active salt is aluminum
SA t and one whie highly hy drolyzed. *. The
Sn sults of nitric, liydrochloric, and
9$ 7i -t4a*hii. the nonovalent salts of sodium,
ad~. d luaius n lepat active. The acids are stronger
stbut the trivalent salt, aluminum sul-
rth ~~~~toany of th acids. Nitric acid is the strongest,
con a phuric third. Likewise the nitrates and
-i streigp t than the sulphates. This indicates that the
iili na ra botto: the acidity and the basicity.
ed ,fr aci~ auese much-less flocculation than the
........ : ,
s, ~i o sti &W~:s been able to satisfactorily explain
~~ omenon, although vicious theories have been advanced.-
w t is ~~bably to 4 found within the realm of collord
y. ~~ll.al Mosison ggest that some physicist must first
j..pt & atiafato q action of Brownian motion. They'
Sr tly gesd :,t possible presence of free alkali derived
IAr1r 1&ifis of -the suspended material and that floe-
t~aeues n these are neutralized. Hilgard assumed a chem-
dation of the fine particles of clay when in suspension which
.l.a. was addId became dehydrated, causing a flocculation of

t?. composition of soil colloids little is known. While
Shav e assumed them to be inorganic it is probable that
Siuatferistie of the states of matter from which they are
not of any particular substance, they may be partly
pkee suggests that organic colloids may coat the soil


r I,' r. rrg1 JaistL, i 9M0)- Nal pp. 41-0i; 170 (18l0), No 1, pp. 4867.


.. .. .. 0
... .. .. : .. ...





























in Hawaiian soils. At all events the flocculation of T,.a
is influenced as follows:
(1) Most acids and neutrAl salts, especially electrolyte4
-the degree of flocculation. .
(2) Highly dissociated acids are the strongest coagulaztwi
less dissociated acids act more or less in proportion to their:
ionization.
(3) Electrolytes of greater valency possess a greater
flocculation than those of lesser valency.
(4) Most highly dissociated alkalis are strongest deflot iA
are also the alkali salts of weak acids, such as phosph oriXc .S...
(5) Ammonium hydroxid is an exception, being only'
ionized, but at the same time it is the strongest deflocclaa .-W
(6) The degree of flocculation depends upon the strength or
of the anion as well as of that of the cation.
COHESION.
The film of moisture around soil particles imparts to them
by which the particles are bound together. As the moisture
decreases surface tension of the film increases. and the particles
drawn together. Hence, in a clay soil where shrinkage is g
there results the formation of cracks. There is a deini~t
content at which tenacity of the soil particles is at a : njp m,
texture is best for culture, and the whole environments most .
ducive to the best plant growth. The factors bringing about



..... .. .. **.;. .. .I
"? ,.. ... .,,









and he resaseor absence, of eietain soluble imbs
ofmdeigthoe efteet of, salts upon this o(hps'v
Of wailan 661l1S the procedure described by the "Burea U- of
Used-,. In this procedure. a mechanical shaker hatvitg
apaatto and..operated by a motor is Iused to insure a
tMsoi'aind by means of a penetrating apparatus" the weight
o ause, a steel cone-haped needle to penetrate 'a ftred
Sed. While the, results so obtained are not directly
-rth results obtained by other investigators, due to slight
iWeh may result from the construction of the apparatus,
d66taparable among themselves.
Ik are shown the salts usod in the experiments and the
with varying, moist ure contents,. 1,500 grams of soil
in maigteaIn.




algd i maingthedetermainatioi* After each penetration
goaded, as shown in 'the tables*, wellmixe with the soil and
'16 tant) one hour before repeating the -penetration test. -Five
tnsWere maL'de on each cup of soil and the average taken.
4Vq" w as refilled. for Ifurther operations, repeating these some
or more times, at each moisture content if there was any undue
Water was added u-p to the point at which it was impos-
towork, the oi: 'Salts were added at the rat of 15 gramse
grams goil), or 1pe cn ofslt. Portions wore taken from
6Pfor inoisture determination.
YAfeeR ofXa on cohesin in Soils under various percentages of moisture.
SOIL NO. 573.

1o30im Cacu kluperphos- Ammonium EodimM Sodian
sulpate eid. phat. slphate. nitrate. carbonte.
as wo o~u

141












Ga.Prd i.Pr.O. Per d. Gm. Per d. Gm. Per d. Grm. Per d. .
=X 2
L27.25 1 6 '12.2 5.8 6 5 15. 55"29. 2o' 1&.43"28.60 14. 56"28.55"16. 94"27. 3D
2485 19. 14 2& 25 17.@2 27. 55 1L7. 60 30- 15 17. 87 27. 50 1& 05 29. 96 19. 26 27-365
go 9 21. 94 25- 15 2D. 40 2&. 8 21. 22 29- 15 20- 54 27. 7 21. 10 27. 40 21. 70 27.-15
21L40 24_ 72 2& 20 22,96 2&.25 23.02 26.35 23.15 27.06 23.78 2&.25 24.07 27.3D
SOIL NO. 530.

AI 75 7. 14 4&. 9 8 55.5 7 74.2 7 75.6 8 65.7 .4 o
0 4,26 11-43 49. 11-61 486 10 B0 51-75 11-60 5L5 12.56 M1.6 11-02 ft 73
454 30 14. 84 M5 2 14. 5D 40. 7 1t 44 50. 5 M5 02 W3O l5 19 7 40. 9: M8 88 61.0
4e50 16. SO. 52. 0 17.-10 52. 2 17- 42 .52. 46 17. 32 49. 7 1&. OD ftO 4 A6 76 ft 0
JU*4 21.68 5121-60 47.0 1M.88 47-46 20.0 A& 55 20.31 47-95 ...... ...
2 .B NLA.,BW OSBLE I)

































: ** ... *.. : ..... :: ::. ,.:.' .: ..*... :: ,* : ..., :. ..:.* :. ..* :....i-.. .*..." ii
*SOIL "SO;: ," :-:....
>... -. *. ', :.... ....j ...irt
._________________________________________________________.- ___________ *** ''** L ..=.I! ^ i


11.23
15. 11
17.96
18.50
21.90
25.33


37.85
35.40
31.6
31.75
30.3
28.4


12.97
16.42
19.10
21.98
24.96


34.6
35.95
35.0.
33.1
31.15


1.4.44 35.1
18.39 32.95
20.00 84.5
22.75 81.25
26.62 30.5


S19.50,I
22.42
25.34


3S. 25
34. : .
32.75


".:
i-


*.:. ..'


Y::
II-ilt
1-11111
rll
-11-i1~


1r: E4;.

6 -.

1'


'!|

* 64
fl 4~~i


.: ,"' "* : "' "" "" .. o. ..... '* 'i ; :1'i .. ...?i.......: .''
Soil No. 573, given in Table X, is the silty org awiei*~
required for penetration increased at first and theM
increase in moisture content, reaching -a minaimuimat: Iat
which is apparently the optimum moisture conte:ift : i$kiM
soil. The effect of the addition of salts is to increase -ta
essary for penetration at the optimum moisture conte4, thad
increase the cohesion of the soil particles. This is especially i
lime. The cohesion apparently does not vary with change in f
content in the presence of sodium carbonate.
Soil No. 580.-Table X shows the relation between: imbsi l
tent and cohesion for the predominating red type of day s il
teen per cent moisture represents the.point above which it:i$
ble to work with this type, due to the fact that the siil': "iwi
through the screen used in the apparatus. The figure
show an optimum moisture content of about 10 per cent if ..
are to be drawn from the theories advanced by previous .inSi
However, 10 per cent is rather low for this type of soil and if ::j
able that the optimum point for plant growth is above t ': 4
the experiment. The cohesion of this sdil decreases at fi1.t:
increases up to 16 per cent moisture, followed by a second 'dec
The remarkable effect of sodium carbonate (and this Would ap
more or lessdegree to all deflocculating agents) is clealy sh...n a
table. Regarding the effect of other salts, little cane bi e.di&I
the data at hand. That they do affect cohesion thee i~ I&BM ub
it is impossible to definitely classify these effects.


Ii


: :... .. : ...
....
-Ii


.. .. i H


i


..61:-


I


-L


4 1


- I


I a I











lo

I?


omerved41th thie other moils Ji tht the de-
arqrular# =4i rpid as Ia result of increasing, the
p "0 th opUsam *Point.' The effect' of salts is' to
a of thi yp of soiL Ttis fact was found to be
wing' to a lack of sufficient soil, ammonium
adi'lao Wtra~to were not used.
ihswork, wae Was exercised to su 'Nect each CUP -of soil
proedue.Penetrations were made at. equaldistances
of thi Oup, the weight was allowed to fall through:
:nd siilr ethods u sea -through4out-. Even with.
-re

it iaf iffieult to obtain' cosl agreeing rSults
filr hut very concordant results were obtained from

A" AR=T SPECMFC G]RAVIT.
*Mlated to cohesion and--bearing d~irecl on the swelling of
etting'U _n "hikn n rciguon drying i's the appar-
4 gaviy, the relation between the weight of a soil and the
it ocupes.This property has: been supposed to be at a
a s he "moisture content of the sofl. Like 0l
prop-it is, subjpet to- modification and is more or less
'by the %ao no factors that affect the cohesive power-
sam apersusused for penetration experiments was used for
J61






I ir J~ttiot cif the appareadt specific gravity. The data were
edby diirididg the weight. of the soil- in the container by its
.'The results are given hi Tatble. XI.
t4*jii~j .-Efect of salts and mZoisure 4ontet on appamet specific graviky


Potesum Chikn hs-Ammonium SodamI Bodhum
SW sulphate. nitrato. bo
174








Ap. Ap Ap- Ap- Ap- AP
Malat- oist : oIsIt- paren Htt, HAWois-t- MOW n M- poent
408. con.can- a con- co- o-
Trdgry en.gtent ntgry tent. Vr_ t"nt lv ent, re

Per Ot. Pdr d. per a. ftro.: PAr d. Per CL
I&? so ]ANa a6We 1&43 6W@ Mi M I& IM 0i.' 6 oW
it U 17MI. 17.1 _M 17.7 M4 I& Gom 1920s
S 21. 2& L 8 2. 06 21. M 1 82
SIN MM-al 1
2L 2 z L LU2& a
t l

























SOIL NO. 516. .

10.95 0.8035........ ... ....... ....... ....... ..... .. .. ......... .. ... ... .:..".
15.14 .8973 14.190.9026 12.33 0.8886 13.09 08859 11.4 0.866 1. i
18.54 .909617.77 .9219 1. 96 .9351 16.51 .9158 15.01 -.945 1 .8
21.26 .8219 21.16 .8140 19.12 .8886 19.11 .8570 1822: .8982 17.46
24.13 .7403 23. 67 .7517 21.71 .8035 22.461 .7781 2.86 .8219 -20.90
26.711 .6675 26.11 .6833 24.77 .7210 24.95 .71.40 22.21 .7540 22.70 .



11.23 0.7394 ........... ... ....... ....... ....... ...... .. ..... .. ....... ....... .....
15.11....... 12.97 0.7403 14.44 0.7517 13.14 0.7245........................... .
17.96 .7464 16.42 .7342 1839 .7245 17.30 .7166.......................
18.50 .7175 19.10 .7079 20.00 .7079 19.50 .7008.........O.............. '::..:
21.90 .6737 21.98 .67801 22.75 .6789 22.42 .6701.. ...... ... .. ..... ..1..
25.33 .403 2486 .6377 26.62 .6684 25.34 .6623....................

In soil No. 573 specific gravity decreases regularly with in
in moisture content up to the optimum both in the untreated 1,4:
in those treated with salts. The effect of salts is not striking
some cases increases, in others decreases, the apparent specific A ...
In soil No. 530 the results are very similar to those obtainedJ..
cohesion tests. This type shows an increase in specific gravity
a maximum, above which point it decreases to what has been
to be the optimum point. Calcium oxid, superphosphate,
sulphate, sodium nitrate, and sodium carbonate decrease the S
gravity, while potassium sulphate slightly increases it, differing
siderably from their action on the previous soil.
With soil No. 516 the results are similar to those with No.
that the apparent specific gravity increases with increase in m
content to 18.5 per cent, beyond which it decreases to the op
point. All salts affect this soil in the same manner, resulting,
increase in apparent specific gravity, sodium carbonate ha-vi
greatest effect.
Soil No. 428 shows the same relation between apparent, sp
gravity and moisture content as soils Nos. 516 and 530. The


'i
,....,,,:: .,1
.'.11. ..:.









Thysickl~OW deg e sols kno as ohesiou aski
VwraV, ar3*more or bem epmndefttupon and govmrned
+'and it is shown in ihe table that the etwt of
oltue ontenoms -and addition of salts is similar. Toth
me6nvv,. *ioth Ioint I 89wna that of optinumh moigtuie
dhis onceded to be the stage mist fa-vorable to plant
these properties wre of special significance, mi soil
MI

"IS

















1 VI
A00/STURE CON 7Ed V
NW- 3-Reat6on between eoheston, apparet specul gravity,, and maisture content of soda.
I clssifying the Hawaniian types of soil according to theme prop.:
sthe clay soil possesses the highest cohesive properties, the man.
as iltnext, the sandy soil third, whl the lowest and hence the
ftesily cultivated i's the silty soil, No. 573. 'The same relation
lisalso to the apparent specific gravity and is true not only at
optImIurnm moisture contest but also on the air-dry soils. The
toshown in figure 3 well illustrates the relationship existing.
fealues two: properties of Hawaiian, soils. At the lower
con ntents the cunrym diverge connsider, h~ly while above a given.
Ihe gi olwsnlrlns























stand one week in the open air. Weighings were mad at
following which all the samples were placed in the samne dei
calcium chlorid and weighing were again made after on wM!
results are given in Table XII.

TABLE XII.-Efect of aalts on vapor pressure.

| oil No. 530. Boi No. 573. I Soil No. 428. '


Salts and fertilizers. dded.t


Water retained. Water retained. Water retained. W e
._ I ._ .i"_


In des- In Indes- In dae
n air. icciccator. iccator. nair. ictor., 44-W

OG. Per ct. Per t. t. Per ct. Per t. Per t. P 'AP
Sodium carbonate.......... 0.10 65.3 46.0 39.4 20.9 39.2, ,31.9 W.
Sodium nitrate ............. 09 71.2 55.5 50.0 38.2 44.1 38.8 4&8
Magnesium oxid............ .04 64.2 43.6 45.7 26.0 44.4 38.2 d4S I..
Calcium carbonate.......... .10 66.2 42.7 41.0 21.6 44.3 35.3 4t
Calcium phosphate......... .23 52.8 21.0 42.7 15.2 43.0 30.7 4. 1
Calciumoxid.............-. 06 58.6 29.7 44.8 24.4 39,8 31.5 44.
Potassium phosphate..... 21 51.4 26.9 41.3 19.3 42.4 25.4 35.
Potassiumsulphate......... .17 62.7 42.9 48.1 33.6 39.5 31.2 37.
Ammonium sulphate....... .13 73.9 61.3 41.7 26.4 43.0 31.7 IL
Potassium chlorid.......... .08 50.2 28.2 45.8 21.7 40.2 40.5 448
Superphosphate............ .10 63.3 43.3 44.7 27.4 42.8 25.7 384 ;1
Acid phosphate............ .10 77.0 60.2 45.8 28.5 41.3 15.3 37.58.
Cottonseed meal.....-..... .10 32.5 8.0 41.5 9.7 43.3 23.1 a 4
Blood...................... .10 42.6 16.2 36.1 7.2 48.7 28. 4S.8
Acid phosphate and blood.. .10 44.0 9.5 31.2 4.3 41.4 24.8 40.7
Potassium sulphate and
acid phosphate........... .10 58.2 25.6 40.3 16.2 49.2 303 44.1
2 (NH4)-14-2-----.......----....---- .10 36.5 10.2 39.3 8.3 41.2 19.3 40.4
S(NH4)-9-11 -............... 10 37.8 10.8 35.7 9.6 38.7 17.5 37.2
2(NOa)-14-2 .............. .10 59.6 41.3 45.3 25.6 57.2 22.8 42.4.
Check.......--- ........--...----........ 48.0 24.6 36.3 15.3 37.0 17.8 36. 4

1 Fertilizer mixtures containing nitrogen, phosphoric acid, and potash in the order and i:,
(percentages) indicated; nitrogen from ammonium sulphate in the first two, from sodium MtS:

These figures indicate that the effect of salts upon vapor pre4"
in soils is one of considerable importance. Salts act upon HINi
soils more or less according to theory. The major part of them inir
the water-holding power in all four soils. Organic substance .
creased evaporation in soils Nos. 530 and 573, but had the op
effect upon Nos. 428 and 516. These results also show that the
of nitrogen used in mixed fertilizers bears a definite relation to ,,
vapor pressure. Those in which sodium nitrate was used shot
A i t .,
...i..

: :















































"WU q'ra WPAU %JtAWS .LLA WAS IUMIuOLP flW t i vuLLLULLL LJJ t6 VL L Va 'VV
2i o- sojf ia saturated atmosphere for 144 hours, after which
ptlm oistwn was determined. Soil No. 428 having the least
ue surface, the highest percentage of organic matter, and the
i motistur content in the air-dry soil, has the least hygroscopic
~.I ^The day s.il, No. 530, has the most exposed surface, the
pll ittage of ferric hydrate, the lowest moisture content in
y foi~nlthe least organic matter content, and next to the lowest
.ower. But asois Nos. 516 and 573, a'manganese silt of
ira~-ncontent and an organic silt, respectively, soils very dissimi-
Baii al.. composition and physical properties, have the highest

power, with the balance in favor of the manganese soil.
S .l XIII.-Percentage of hygroscopic moisture absorbed in 144 hours.
":;!!iiiii "; ':: .


Hygro.
Soil No. ecopc
moisture.

Per entf.
5830....... 19.32
573....... 21.59
428....... 15.56
516....... 2L.0


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Salts and fertilizers. / oil
-No. 530. 5No. 73. No.4l. No

Per cent. Per Cet. PercentP.
Original moisture content of soils.................... 3.17 10.84 9.87
Potassium sulphate................................ 17.21 19.35 14.80
Calcium oxid.. ..................................... 16.78 19.80 14.0
Acid phosphate..................................... 16.76 17.88 13.90
Ammonium sulphate ............................... 17.08 -18.70 .15.53
Sodium nitrate .................................. 17.28 24.80 .17.4
Sodium carbonate ..................................... 17.64 24.20 15.0
Check......................... ................... 16.35 18.90 14.55
Calcium sulphate........................ ............ 16.26 20.81 13.70
2 (NH4)-14-21 ............-..... ...................... 16. 0 20.20 14. t
2 (NOa)-14-21...................... ................ 16.56 22.00 15. 08
Superphosphate ................................. 17.07 20.30 13.80 2
Potassium sulphate and acid phosphate............. 16.50 18.50 14.35 21
Sodium chloride .................................... 8.95 32.00 22.02 30.0
Check .............................. ................. 16.35 18 58 14.58 .

SFertilizer mixtures containing nitrogen, phosphoric acid, and potash in the order and
(percentages) named; nitrogen from ammonum sulphate in he first, from sodium nitrate i

The effect of adding salts upon the ferruginous clay is to i:
the hygroscopic power in every instance, except where calcti
phate is added, in which case there is very little variation.' 5
matter of fact the general tendency of all the salts on the
types is to increase this property of soils, and in cases where
a decrease it is almost negligible. Sodium chlorid, being ;i .
hygroscopic salt, imparts the highest absorbing power to th
while the lowest is effected by addition of acid phosphate.''

SUMM ARY.
.. .., ..
The foregoing pages contain data obtained from an extensive siia
of the physical properties of Hawaiian soils and the effect of fertiRt
upon these properties. It is evident that agents which influence t
mechanical condition are many and complex. It has also been clear
demonstrated that the addition of salts or fertilizing materials affl
the structure of the soil.
It is impossible to predict in all cases the degree to which any 4
or all physical properties will be influenced by the addition of a .c










Woe sit MarMet looknova How we, within nal
of sk ga lare appuiation of a sat oily 11110111
appictin.This suggets- that the measurement
effort may be just as accurately, and possibly more,
Uwmiedthan the chemical effect. The measurtement*
_-application of fertilizer through a chemical analysis of-
impossible.
isdimi-nished in clay so&l by the addition of &&Its but
a sndysoils. Also this property is more active in silts
knyor clay soils, being slowest "in thei latter.
&Wation of water 'is most rapid in sandy soils and slowest
phearticles'of which are most likely to swell. Fertilizers
blyinrese t6e resistance to percolation. The theory that
Watercapillary activity offer' the least res-istaince to perco-
water does not apply to Hawaiian soils.
nereaSe or diminish the size of the soil aggregates.Ti
allimportance in-the use of fertihizers.
nof the soil particles 'in most Mistances is increased by
n of salts. This is also true of the apparent specific
However, there, are too: many exceptions to make any
statement.
hygroscopic- moisture is Micreased by the addition of salts,
btver~y few exceptions.
vapor pressure is lowered in most instances, but can not be
from a consideration of the surface, tension of the added

,,Uwwledgm~ents axe due and thanks'hereby extended to Dr.
]R.Kelley for- valuable suggestions and for interest shown
tll














ut this investigations





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