Note: Descriptions are shown in the official language in which they were submitted.
Tl~e present invention reLates to new soil conditioners for
improving soil structure and to r,~et}lods for their manufacture.
As known, tlle structure~of a soil determines a large nl~nber of
its ~roperti~s suclt as permeability ~o water~ ~orosity, crust formcl~ion,
S aera~ion etc. ~m improved structure will be beneficial to the prevention
of erosion by liater, increase in crop yields etc. It also simplifies
tl~e mecllanical preparation ol the ~ield before planting. ~\n increase
in a~regate size alld in per cent of aggrega~es will reduce n~ d
eroslon. It ~iill also recluce a lligh penetration o:E rain in~o the soil
~0 and will improve l~ater holdillg capacity and reduce evaporation, the
result of l~llicll is a better ~ater balallce in arid ~ones. Of special
importance is t}le prevention of crus~ formation due to puddling by rain
drops, Prevention of this puddling, allows for a better rain infiltration
into tlle soil and causes a reduction of rlm of~ llith a consequent erosion
decrease. The crust prevention improves gerrnination and aeration of
sa~lings.
It has been postulated tllat the di~ferences in structure between
the ~mdesirable and tile desirable types of soils are attributable to
differences in the type of the electrical charges of the individual soil
~0 particles. Accordingly, it has been proposed to condition or to im~rove
poor soils, for example structurally unclesirable clàyey and loam soils~
by applying to them certain synthetic yolyelectrolytes which are water
soluble, partially water soluble or l~ater insoluble. ~lese are mainly
based on polyacrylaniides, polyJ~Iethyl-acrylonitriles, copolymers o~
acrylonitriles wi~h vinyl acetate etc. ~lus, for exa~le, U.S. Patent
No. 2,625.~71 claims a copolymer containing 80-84% acryloni~rile,
11-15~ meth~crylonitrile and 5% vinyl acetate and hydrolysed in order to
make it hydropllilic. U.S. Patent No. 2,8~7.392 describes a co~lolymer
containing 50% metllacrylonitrile and 50% butadiene. U.S. Patent No.
2~7~5.2'70 claims a modification of polymetllylacrylonitrile~ after
llydrolysis to the acidic form~ the polymer is absorbed on *o ~he surface
o vermiculite particles and used in this form as soil conditioner.
Altllough these polyelectrolytes have been used successfully in a
n~mber o 1imi-ted applications, such as llouse gardening, tiley have not
become ~idespread due to one or more of ~he following reasons:
~.
.~,
i;8~
~a) Tlley c~r_ too ex?ensive for large scale ~e.
(b) ~le streng*ll oE bonds lloldillg the par~icles of soil in cm aggrega~e~
is too higll and t]lus detrir,lelltal or certain ~roycrties.
~c) Very oten they ap~ear in a ~OWàer form, WhiC]I causes problems in
s tileir s~orage and is very inefficient in field aI)plica~ion.
~d~ ~ome o tnelllllave toxical proper~ies :~or ~nimals and `tuullall beings.
(e) Some of tilem are easily decomposed by bacteria present in ~l~e soil.
~f) Some o~ -tllem are not suf~icien*ly stable even for a complete season
~eillg readily deco~nposable and washed out.
efcrences are encountered describing the use of li~osulfonatc
as ;oil contlitioller. Some improved results are claimed to be achieved in
ol)tainillg soil agg~egctes using amounts o~ about 2~ or more by weigh~
lignQslllEonate. ~lol~evcr, 5uC}I relatively large amoullts of lignosulfona~e
become expensive in application as ~ell as in manipu~ation and also
raise ~roblems concerning the bacterial activities in the soil. Also the
hi~l~ lignosulonate concentration affects the soil chemical properties
important for plant nutri*ion. ~le lignosulfonate is leaclled through the
soil and thus is wasted ~o a large extent; it also pene*rates to certain
layers where it is not nee~led and may even ~e harmful and cause problems
of contamination. Large amounts of lignosulfonate also tend to produce
a massivc ratiler than the friable aerated structure desirable in most
soils for agricultural purposcs. The lignosulfonates may become
irreversibly dîsactivated by some mul_tivalent cations and at the same
tlme when applied in large amounts deprive the plants from some of the
~5 necessnry microelements.
In our co~endillg patellt application No. 267~239, new soil conditioners
were yrovided t~hich were made by the graft polymerization o an acrylic
n~ollo~ner an(l crude lignosulonate in the presence of an initiator. According
to the present lnvention it has been fowld that other monomers can be
successfully utili~ed in order to manufa~ture new soil conditioners.
.~ .
35i8~
us the invention consists of soil conditioners WiliCh are produced by
the grat ~olymeri~ation of a vinylic monomer with crucle lignosulfona-te
in tlle ~resence o~ an initiator. ~ne vinylic rmonomer can be any one
selected rom tlle group of vinyl benzene (styrene), vinyl acetate~ hyclrolysed
i vinyl acetate, vinyl cyanicle (acrylonitrile), vinyl cllloride, vinyl
pyridine, vinyl butadiene etc. It is also possible to use a combination
of two or ntore of the abQve monomers or ac~nixed Witll any one of the acrylic
n~ollolllers described in the parent patent application.
One of tlle ~naill objects of the soil conditioners according to the
resent invelltion is to im~rove the soil structure. Y'hls is contrary to ~he
ef~cct obtainecl by other materials, which cause soil solidification i.e.
il~creased soil strength.
.
ADlong the adYantages o~ the new soil conditioners, the following can
be mentionecl: ~1) Their manufacture is very simple, (2) they are relatively
1~ ine~c~)ellsive, (3) the amount of the vinylic component in the graft polymer
m~y be small. Tl~us for example it was found that, instead of using equal
~arts ~y weigl~t o vinylic monomer and crude lignosul-fonate, even only one
rt of vinylic monomer to 6 or 8 palts o crude lignosulfonate can be used,
de~ending an the ty~e of soil required ~o be conclitioned and the specific
goal desired. For example, for conditioning a soil in order to ~rotect it
from erosion by rain and to prevent crust :c~ormation, it has been ouncl that
a graft polymer containing 0.6 parts ~inyl acetate and 1 part lignosulfonate
gave almost the same results as a ~raft polymer pre~ared from 1 part vinyl
acetate and 1 part lignos~llfonate. Of course the latter graft yolymer~
~5 colltai~ g as it does more o the vinylic component, will be relatively
more ex~ensive than the forlller one. The higher vinylic component in the
grat ~olymer results in ~I soil conditioner with a hig}ler molecular wei~ht
and stronger bonds with the soil.
~ pClSOII skilled in the art af-ter reading the present specification
3~ wlll certainly be able to determine the proper ratio between the lignosulfonate
and a p~rticular vinylic monomer in order to obtain the soil conditloner
most stutable ~or the l)u~pose recluire~l. It is also ~ossible to use a ~ixture
of two or more graft ~olymers prepared separately Wi~}l different monomers
or diffelent ratios between lignosulfonate and vinylic monomers. In this
s~ manner each conditioner in the mixture will act on the soil according ~o i~s
~rj
.
.
' '
3~
composition, for tl.e specific goal. For e~a~ple if ~he condi~ioner is to
be s~rayed, one niay use a mix~ure o, two types. One type ~ould be of a
higher molecular weigllt for stronger bonds at ~he surface. ~le other may
be of a lo~icr molecular weigllt to improve the penctration ~low the
surface.
Conditioners of di:Eferellt compositions may form better boncls with
clif~e~ent constituents in the svil. For example, graf~ polyl,\ers witll
acrylonitrile, metllyl acrylate or l~oth, form better bonds with particles
o CaCO3 wllile a gra~`t polymer with acrylic acid is just as good with ine
llOUg]l silica and clay minerals.
According to a preferred embodiment of tlle ~resent invention~ it is
possible to pol~nerize the crude lignosulfonate with ~wo or more vinylic
monoillers in the same reactor. The two or more vinylic monomers may be
illtro~uced eitller togetller, whereby thc graft polymerization occurs
1~ simultancously or separately, whereby the graft polymerizations with each
mollomer will occur consequently. There are cases, ~or exaLmple, when
vinyl acetate is utilized, where the polymcrization should be carried out
in an atmosphere of nitrogen in order to prevent any possible inhibition
by o~idation of ~he monomer. rnere are common e~pe~lients known to any
person skilled in the art o polymerizing such monomers.
l~Le term "crude lignosulfonate" as is used in the present specification,
includes the aqueous solution resulting from the processing o-f plants or
~ood for the separation oE cellulose and lignosulonic aoid or sal~s thereof
as obtained without any puriication. ~le constitution of the crude
~5 lignosulfollate varies depellding on the type o plant or IYOOd u~ilized and
on the method o processing; it appears generally in the orm of Ma .~ NH~
or Ca salts along with other polysaccharides, which for cert~in uses are
harr,~ul and have to be removed. It has been found tha~ tl~e lignosulfonate
salts to be utilized in the method according ~o the present invention, may
3V be in the crude form, which is also less expensive than the puri~ied form,
witllout im~airing the activity per unit weight of the soil conditioner.
Fllrthermore, experiments with certain materials indicated higher activity
per ~it welght of a soil conditioner procluced from crucLe lignosulfonate;
it goes however without saying that purified polysacchcLride - free
lignosulfonate, often also referred to as lignosul~onic acid or lignosulfonate
salts ~ay also be utilized.
.~
.
r,l~ graft poly~neri~ati~n bet~ieen the vinylic ~onomer an~l t}~e
lignosulfonate is a sirllp1~ addi~ion reac~ion 1~nic1l occurs generally at a
pl-l in tlle range of 2 to 6 and preferaloly in the ~ange oE 3 to ~. The
product obtained is stable and even a E~er n~ore t~an one year of storage
no cllange in its structure or in tlle results ob-tainecl from its utilization
were observed. Tlle soil conclitioners obtained may be cïried or exc~nple by
spray dryer ancl stored or used in a powder Eorlm
Tlle grat polymers ol)~ained in accordance with the present inventlon
;II'C usecl preerably in their hydrophilic form ~hicil recluired l~ydrolysis oflU ~lle ~olyn~er for ~YIlich tile knol~n ~uethods l~ith an alkaline solution Sucll as
NaOil, ~OIi, Ca(O}1)2 or ~ OH are usc)d; where the graft polymer also
includes acry~ic acicl "nethacrylic acid~ or hydrolysed vinyl ace-tnte as
on~ of the mollo~ners l~hich already possess a llydrophilic character only
~)artial hydrolysis may or mere neutralization be required. Beore hydrolysis
l!i it c~n le ol~tainecl as a,l emulsion with a ~elatively gooci stability.
I`lle initia~or recluired to be present in the graft polymeriza~ion can
l)e selected rom kllowll reagents usecl in this -type of reaction e.g. hydroge
peroxi(le or various organic perocides such as cumene hydroperoxide. It is
nlso possible to initlate tlle polynlerization reaction by purely pilysical
n~eans, sucll as ultraviolet racl:iat:ion.
~le vinylic mono1llers may be u~ilized such as are commercially available
t~ithout any prior treatn~ent ~e.g. distilling out the inhibitors ganerally
usecl or tlleir storage). ~ person s~illed in the art Oll polymerization will
selcct the proper reagent -~or parforming the grat polymeriza-~ion~ ma]cillg
IlSe o tl~e available commodities and reagents.
Colllpared ~ith ti~e known polyelectrolytes ba~sed on acrylonitlile
copolyalers~ as clescribed in the prior art~ the new soil conditiollers
accol~dillg to the present invention, are claimed to be much superior being
cl~aracterized by tile follo~ing improved properties;
~0 1. Tlley h2ve a long shsl li:Ee without special storage precautions such
as clry atmospllere, darkness or oxygen-ree atmosphere.
2. The molecular weight of tlle graft polymer according to -the present
invention is re~luced and therefore the nu]nber of effective bonds per
unit weight of soil conditioner is il~creased facilitating a more
uniforl~ s~readillg of the conditioner througll the soil and thus a
greater efficiency.
3. Tlle graft polyDIer is more soluble and thus less sensitive to possible
furt}ler polymerization or setting with time.
4. Tlle bonds Eormed between the new conditioner and t~le soil are strong
enoug}l for maintainillg an aggregate of the proper magnitude, but not
too strong so as to cause the formation of large soil cloc~ or too
strong clods or not sufficiently permeable to permit adequate
movelllent o water, air and nutrients into the soil treated.
S. rlle boncls formecl are at least partially regenerative, whicll means that
the asgregate property of the soil persists even ~fter several cycles
lS of rain, drying and working of the soil.
6. Tlle graft polymers are water soluble or may be produced as stable
suspensions which can be easily transferred and diluted.
7. The hydrolysed graft polymers are not sensitive to solutions of many
electrolytes even at high concentrations which enable use of water of
various qualities.
8. 'rl~ey are practically non-toxic.
9. ~lost of them can be diluted to any extent and sprayed without problems
of clogging the nozzles or pipes.
10. Il~e properties o the soil conditioners may be changed by varying the
2$ proportions between the monomers and lignosulonate as well as the
extent of hydrolysis.
Concerning the procluction of the new soil conditions, the process involved
is characterized by the following advantages:
j,~,,
e main component, ~ osulolla~e, is a low cost raw m~terial whicl~
today is an environmental ~urden.
2. ~le process does not require the removal of tihe inhibitors fro~ the
vinylic monomers, as generally encountered in such grat polymeri~ation.
3. ,~llen emulsions are desirable to be prepared~ no ad~itional surEace
active agen~s or organic solvents are required.
4. l~e reaction occurs at ambient temperatures and in most o ~he cases
at atmos~l~eric pressur&. Generally the reaction time is about 5 minutes
` at a temperature of l~etween 30 to 9SC~
10- 5. ~le ~olymsrization of the monomers is almost complete leaving only
~races of monomcr ~mich lllay be left in the end produc-t.
6. Tap water or even ~ith a higher salt content may be utilized.
Tlle application of the soil condi~ioners prepared in accordance with
the present invent:ion can be done by the known methods. ~hen used in the
solid form, it can be mixed ~ith the soil or spread mechanically~ watering
and if necessary rewor~ing the mixture. I~len usecl as an aqueous solution~
the soil conditioner is simply mixed with the wet soil. The soil conditioner
may be also applied together with the irrigation water. The amount of soil
conditioner to be given will vary fr~m soil to soil in accordance ~ith ~he
goal envisaged; th~ :Eor example, for a loess-type soil, illTproved results
in the structure, such as increased aggregation, were obtained by using
bet~een C3.025o and 0.1% by lYt of the soil. Hi~her amoullts of soil
conditioner, up to 0.2% by \~t ~on a dry basis) will further increase the
proportion of stable aggregates~ but this will gen2rally not be econon\ically
attractive. For soil stren~thening in construc~ion work however, higller
no~ults may b~ recon~ended.
preerred method for the application of the new soil conditloner,
~hicll is 3nuch simpler than the above Xnomn l~ays, is by spraying the aqueous
solution di~ectly on the soil. This method of application for soil condition-
ing has become possible, thanks to the particular properties of the copolymer
obtained according to the present invention.
X`
., .
- . . . .
I~ has beell fo~lcl tha~ the condi -tioner sprayed on -~o tll~ s oi 1 -.~orms
a protective layer ~hicil prevents aggrega~e brea~age by action of rain~rops
o~ ind erosion. ~le rate of ~ater iililtration into tlle soil is maintained,
~reventing the for~lation of an impermeable crllst by the i~npact o-f
raindro~s. It also improves the regeneration of infiltra~ion capacity after
drying and th~ls hel~s in the germination of seeds.
It l~as beell fo~uld -that by repeated spraying, dryirlg and sllallow
cultivatioll, all excellent protective mulc}l layar is producecl wJlicil is ~ellaorated, reduces the evaporation Erom the soil and thus re-~ains the ~ater,
alld leads to m~r~e~ly il~proved crop ~ie:lds. This has a s-~ecial in~ortance
~here Cl`USt fOrlllatiOlI iS detrimelltal and water supply is limited.
Instead of usillg aqueous solutions~ the hydroly~ed graft polymer
obtained according to the present invention~ may be sprayed admixed with an
~queous f~rtilizer sucl~ as anullonia solution. In this manner the incorporationlS of tlle soil con~itioner is carrie~ out at the same time as the fer~ er
ap~licat:ioll, thlls saving additiollally an agro-technical operation. In a
similar mallller it is also possible to incoryorate the soil conditioner in
various pesticides or herbicides and apply to the soil to~ether wi~h these.
~ccordillg to another embodiment of the present invention, the soil
conditi~nillg apparatus can be mounted on various soil working implements
and es~ecially on the planting macllines. T~is apparatus consists o devices
~or spreading tile conditioner either in powder form or preferably in an
aqueous solution on to the soil. ~le soil with ~li.Ch the seeds are covered,
will already contaill the conditioner reagent and thus will retain good wELter
iniltr~tion and good aeration prospects even after heavy rains or irrigation.
Tllis combined operation o~ simultaneous planting and soil sta~ilizatioTI can
be carried Ollt by the simple addition o the appropriate nozzles in front
of, besides or behind the planting tool. Generally speaking, the amount
of soil conditioller needed is about 20 to 50 ~g. ~er hectare o soil.
LRrger amounts can be used with better results howeve~ are less attractive
~rom an economical point of view. It has been fo~md that the application
oE the ne~ soil condi~ioll can also be carried out on an area of limited
extellt in strips, or on ~atches of soil. Better results are obtained with
larger water dilution and in humid soil.
~r
- 10
~ne ii~proved results oE soil condi~ionillg olrtaine~ with ~le grat
polymers according to the present invention were substantiated both in
laboratory and in ield ~ests, and muc]l better results as regards the
s~ability oF ag~regates than those ob-tained with a l~nowll acryllc polymer
~manu~actured and marlceted by ~lollsanto ullder the Trade ;~iark of '~7~ryli~lm')
~ere ac.~ieved. [t ~as founcl that the beneEicial e~fec-t oE the ne~ soil
conditioners on aggrc~ate fc)r~l~ation appc-~ars evcn with a v~ry l~w -~)ercentage
of soil con~itioner produced according to the ~7resent inveiltion.
I~igule 1 illustrates in grapllic for~n t}~e percelltage of s-~able aggregates
10 largcr ~ all 0.1 mm (by wet sieving) in a loess type soil obtailled, as a
functioll of tl-c ~ercentage (by wt) of conditioner used. For comparison,
correspondillg tests were perormed l~ith crude lignosulIollate - given in
Gra~ll 1 - and witll the sa~e "Kryliu~i' given in Grapll 2. rhe im~roved resultsof the nes~ soil conditioner are self-evident. l~hereas witll an amou~lt of
15 0.05O by wt li~nosulonate or Kryliun~, the stable aggregates were 37~ ancl
~13~ respectively, the stablc aggrega`tes were 67% and 72% (Graphs 3~
Wliell USillg the same amouilt of conditioner ~reparecl accorliing to the present
invention. In Graph 3 the soil conditioner conslsts oE a graE-t polymer oE
0.5 part metllyl acrylate~ 0.5 part acryloilitrile and 1 part lignosulfonate
20 15o(l~y w~) w]~ile in Grapi-l 4 it consists of t'ne same acrylate and acrylonitrile
compositions ~ut tlle lignosulfollate was of a 25~ ~7~y wk) concentration.
The new Ograft polymers obtained according to tlle present invention ]~ave also
various ot}ler uses such as: animal-feed pelletizersJ leather tamling~ cement
products, industrial cleaners~ sequestering agents oE metallic ions e~c.
2S A good illustration of the various effects obtained by *lle soil
conditioners according to the present invention can be presentecl by
sedimentation tests carried out on different soils. An amount of ground
soil was added to water resulting in a suspension of lS0 mls. To the
suspension obtained, an amount of 100 mls of a solution oE soil conditioner
3~ was added, thus resultinO in a total slurry of 250 mls of suspended soil.
rl~e sedimelltation tests measurements were done according to the settling
o the suspension and the relatively clear water layer forllled at the top.
~le readings given in the Eollowing Ta7.~1es are in ~m o~ the settling material
Erom its 7~ottom to the settling level.
~ .
T~BL~ 1.
Us~ of tlle soil condi tioner prep.lred in ~,~amt~le 4
with a calcareous clayish soil
~ _ _ ~ _ _ . _ ~. _ _ _ _ _ _ _ .. . .. _ _
l~t concellt-
l`,l~iOll o Fillal ~0 ne~ soil
soil condi- Re;lding of sedimen~s readiil~ sedin~ent
tiont3~ in at di:~:E2rent times af-te:r 18 iormed
~ L;l~ltes) w ___ ~ __ _ _ llrs.
Cil~ SOll
O ~ 1.0 1.5 2.03.0~.0 5.0 :L0
~..~
5.() 2~ 210 1~-~ 157 1~011094 S5 ~ 50 2S.`2
2.~ 250 210 :L7~ 14812~ 0 89 ~3 68 52 33.
1.0 250 212 17S 1~8 12~10292 ~5 6~ 50 2S.2
0~75 25Q 214 1~2 15~ 1301059~ 86 70 ~9 25.~
0.5 250 ?22 1~5 172 lS2119102. 92 72 ~7 20.5
0.2~ 250 226 206 ~ 1701~3122 105 74 ~5 15.4
~).1 25~ ~2 21~ 20~ lgS162142 125 77 ~3 10.
0 XS0 25V 250 250 250250250 250 230 39 0
rnus adding a 2~ solution of the soil conditioner caused an increase of
33.3% in`volume of the soil~ with a corresponding increased porosity~ and
produced a better germination and ~rowtn in crop thAn tht-3 untreated soil.
~ach soil ~Yill requi~e a different optimal a~nount o:E soil condi~ioner in
order to achieve the hi~hest sediment. ~\t lower concentrations of the soil
conditioner, the flocc~llation effect will be more enhanced~ tne veloci~y
of se~tt1ing tle~ending on the size of agrgregates and their bu1k den~ity.
Tl~e soil conditioner prepared accordilig to ~xample ~ was also tested
~ith a standard kao1in soil. ~le set~ling measure~nents are given in ~lle
ollowing Table 2:
T~`~'., LL 2 .
!~e of -~h" soil conditioner prepclred in 'L~xan~31e 4
~;i-th a. standard lia.olin soil
_ _ _ _ _ _ _ _ _ .. _ _, _ _ _ _ ~ _ _ _ _ _ .. _ _ _ _ ~ . _ . _ _ . . _ _ _ . ,. _ . _ _ _ . . . _ .
~it, COllCen- Fillal '`o lleW
~rat:~on o.i
soil COI~d - l~adings c~f seclil~leuts at read- sedi-
: it.iouer in differe~t times lc~r ment
0/~() oL ~ mi~ tes) L' hrs. forl,led
() l).s1.0 1.~ 2.0 3.~ ~.0 5.010.0
. . .. . _., .. _. .... _ .. _.. ._ ._ .. . _ ..... _ . . .. ~ .. ~.. __.. _. , ~ . _.~_ .. , .. .. _ . ___ _ ___ _. _ _ _
2 . () ~50 170102 73 63 52 47 ~3 36 2635.S
1.~) 25~) LGO92 71 62 53 48 45 38 2742.1
~).7~ l7()')S 76 67 56 51 ~7 39 ~ 47.4
~ llO ~1 7() 5~ S3 ~9 40 ~74~.1
l).'5 250 204150 10~ ~4 G~ 61 55 44 2636.~
).:l 250 21~ 0 :L~6 116 80 66 60 ~5 2~ .3
~0 2S0250 250 250 250 2S0 250 2~0 19
Thus adding 0.75/oo of the soil conditioner caused an increase
of 47.4'`~ in volun~e of tlle soil witll a corresponding increasecL porosity
alld bettcr g~er~ latioll-tllan the ~mtreated soil.
Tl~e. same svil conditioner prepared in ~xample 4, was tested with
a loess ty~)e soil, and the settling measurements obtained are given in
the ollol~ing Table 3:
.~
;8~
TABL~ ~.
__ _._
Use of the soil condi*ioner prepared
~n ~xar,~le 4 with a loess t~e soil.
I~it concen- ~inal % ne~
tratioll o~ read- soll
soil cond- lng sedi-
it.ioller in Readings of sediments at afte-r ment
()/0(~ 0:~ di:Efe-rent times lS hrs. :formecl
tlle soil ~in nulu~tes~
0 0.~ 1.01.52.0 3.0 ~.0 5.010.() %
. ~
1.00 ~50 16~ 107S3 74 67 ~5 6~ 63 62 1~.2
0.75 250 166 107S3 74 S7 65 64 63 62 1~.2
0.50 250 170 10~83 7~ 67 65 6~ 61 60 lS.
~ 5 250 16~ 105~0 72 64 61 60 59 5S 11.5
0.10 250 1~(~ 112S7 7~ 64 ~0 5~ 56 55.5 6.7
0 250 250 2502502~() 250 250 150 220 52.0 0
llere again i~ was found that the adclition of 0.75~oo of the soil
conditioner caus~d an increase of 19.2% in volume o~ ~he soil wi~ll a
corresponding incrcascd porosity, and procluced a better ge.rmination ancl
growth in crop than the ~m-treated soil.
The soil conditioner Rrepared as in ~xample S was tested with a
~aolin soil and the settling measureDIents obtained are gi~en in the
ollowing Table 4:
~1
1~
T~
___
Ijs~ o:~ ~he soil condi~iuner -~re?ared
in ~xample 5 with a kaolln so:il
_ _ _ _ _ _ . _ .
I~'t COllCel~- fillal "~i ile~
~tl;ltion o~ cli~feten~ t.-in~es reac!- scdi-
Lt.iOl~el ~Ln ~ after mel~-t
()/(~() o~' ~LII liUllUteSJ lS h1`5~ :FOrmed
0 0~5l.0 1.5 2 ~ 3.() ~.() 5.010.~ - -
2.~ 250 '02lsa 112 S5 64 56 51 3g 22 15.S
.l.0 2;;~l:L'.~ 2 96 76 62 55 50 40 24 26.3
0.75 250 19S143 '~ 7~ 64 56 52 4:1 ~4.5 28.9
o. r~ 250 20~15~ 112 S5 6~ 59 54 42 2ci 26.3
~ 25~ 21217~ 0 110 7S 66 58 ~c~ 23.5 23.7
O.l 250 22~190 154 t36 '~)3 71 ~2 46 ~2 15.~'
~) 2~0 250~50 250 250 250 250 250240 1'~
Th~ the addition of 0.75/oo o ~lle soil condi~ioller caused
an increase o 2S.9% in volume of t}~e soil witll a corresponding increased
~oroslty, ancl produced a better germination and growth i.n crop -than the
untreated soil.
S ~no~her illus-trati.on o-f -the bene:ficial effects of the soil
condition~rs according -to the present invention, can be presented by thc
~reventioll of wind erosion. Thus for exarmple an amount of 3 g of the
soil conclitioller ~prepared as in E ~Im~le 4) sprayed on to s~ncly areas
~ith 200 ~o 1000 mls o wa.~er ~er squarc me~er, pro~idccl p-ro~ect.i~n
IQ a~ainst ~in~l erosion about one month after seedling of carrots.
It also ill~roved tiheir germinatioll by about 25%.
~X; ,
.
- - . - : : ~ . :
8~;
A sin,ilar test carried out ~ith a loess .ype soil utilizin~ 5 ~/sq.
r.leter of tlle so:il conditioner ~?reparec1 as in ~xample 4~ improved
~el~1ina~ion of carrots ~ h a~out 20o. ~un-o:Ff of irrigati.on 1~atcr c~ue
to crust for]nation 1Yas practically preve1lted ~ to a total of 200 ~n
rain.
1~.ind tunnel field tests on v~rious wind veloc:ities ~er~ carried
out 1~it11 several soils fron1 nortilern Jordan Valley (Israel) until
iltcipient erosion was noticed. '~e soil condition was applie(1 at. a rat~
o 5 g per s~uare meter in 500 1nls of ~ater. ~he results obtaine~ were
l~ 1neasured l5 cm a~ove tlle soil aTlCI are given in the following Table 5:
rAsL~ 5.
Soil type P~a~ ~iarle soil Peat Peat Peat Peat
soil ~Lacustrine) soil soil soil. soil
(~lulla Lake3~Hulla Lake)(Hulla Lake)
~ (1 V~locity
1.5 in kn~ r, ~.it1~
treatec1 soil 60 85 55 55 50 55
1~1ind velocity
in km/hr, with
untreated soil ~8 35 30 3~ 36 36
~e results show evidently the ~eneit of the treated soil with the
soil conditioner accordi.ng to t1le present invention. ~or exan1ple ~hereas
wit1~ a lacustrine soil only at a veloc~ity of S5 1~m/1~r. incipient erosion
~as noticed f.or a treated soil, the same incipient erosion wi~ an
untreated soil was alreacly observed at a velocity of 35 km/hr. only.
In order further and more fully to illustrate the nature of ~his
invention and the manner of practising it, the following ~xamples are
~rcsented fol~ clearness of ~mderstanding only, and no limitation should
~0 ~e ~u1derstood therefrom. The ~qmounts u5sd are expressed in parts by
~ei,~ht ~u1less othe~ise s-tated.
: . - ' , , ~ .:
. ~
s~
- 16
7~ e
100 par-ts of crude lignosulfonate (containillg polysaccharide~ as
o~ained ~rom t~le paper industry) ~ere introduced into ?, reactor ~provi~lecl
Witil a stirrer~ a thermollle~er, and a condenser) -tog~tller with 300 -~a~ts
S of tap water. Subse~uentLy, ~l2 parts of vinyl cya~ no~n l.ulder tl~e
naire o-f acrylonitril~) were ad~ l ind the mixtllre heated to about 5~ C.
lllen 2 parts of hydrogell pero~ide (lO~ by vollu~.le) were iddec! and all
e~otl~ermic reaction sla.s observed. Tlle reaction was kept gOillg at 7~ G
or a :~ew minlltes. T~e product obta.ined was hydrolysed to an ex~ent of
50O by heatlng for two llours a.t SS - 90C with 10S ~arts o:f i'!aO~ solution
~30`O by sit.). Tlle end procluct in the foTm o:E a brolm co:Lloidal solution
as foluld -to be a good soil conditioner ~ilen appli.ed in a concen~ratio
of 0.1~o by ~eigiht to a clayey soil resulting in ~G.4So of wclter stal)le
aguregates (larger than 0.1 llUll).
In this ~xan~le ~no par-t.s o ihe same a~ueous solution of crude
lignosul.ollate~ as that used in ~xample 1, were graft polymeri~ed first
witll 25 parts of methyl acrylate and subsequelltly witll 75 parts of vinyl
cyanide. The conditions of polymerization were the same as in ~.xample :L.
The yroduct obtained s~as follnd to be a goocl soil conditioner~ applied in
a concentration of 0.1% by weig]lt to a c:Layey soil, it gave 5~O of stal)le
aggregates ~larger than 0.1 mm). The same product a:~er complete
hydrol.isation Wit}l NaO~I ~as in ~xample 1) yielded a soil conditioner s~hich
gave 7~.1% s~able aggregates (larger than 0.1 mm) when appl.ied at the same
concentration o 0 1% by wt of the soil.
~xaDl~le 3
~ he experiment ~as simi.lar to that described .in Example 1 but instead
of 42 parts vinyl cyanide (acrylonitrile~ 50 parts of methyl acrylate
and 50 parts of vinyl cyanide were introduced together fo:r the graft
poly!nerization s~ith tlse crude lignosulfoncLte solution. The produc~ ob~ained
~i
.
35~
17
.~EIS comp1ete1~ hyCirG1iseCI ~.'i th ~EIOil as in L~nple l anc! teste~l a~ ,~ soil
COnCIitiOIIer. Tl1Q fO11Ol~Jillg staLle aggregates (by wt sieviilg lar~er th~n
û. 1 1.Ur) ~ere obtained at variolIs amo~ts of soil conclitioners:
O . 05J i)Y w-t 0. 075O bY W~C O .1~o by ~t
of Soil of soil of soil
.~
~tai-lc aggrcg.Ites 65 . 5 69 . O 71 . S
le 4
. _. . ~ _
e e~erililent ns in ~ample 3 was reyeated ~Yith the sa~e amo~nts
but tlle gr.lft polymerization ~-as perormed wi~h 50 parts o~ me~hyl acrylate
- followccl by 50 parts o vinyl cyanide. The product obtailled ~as divided
t:\~o ~atchcs, tlle first being hydrolysed to Em extent of 50% (50O of
~t~e estels I~rollps) ancl thc second completely hydrolysed. Tlle elld prod~Icts~iere tostecI as soil con~itioners and the results~ e,cpressed as a percentage
t5 o stahle a~gregates obtailled were ElS follows:
Stable Aggregates by wet sieving
~larger than O.l IIUll)
0.05~0 by IYt 0.075% by ~t O~1~J by wt
oE soil o soil o soil
. . , .. .. . , .. ~ .. ~
50O IlydrolysedNo~ det~rminedNot determinecl 70.6
l()()"o Ilyclrolys~<I 65.8 71.5 77.8
}~ 1 c~ 5
_ . _
150 parts o~ crude li~nos~llonate were introcluced into a reactor as
;n ~xE~Dple 1, together wi~ 50 parts of t.~p water. ~fter adjus~ing the
~II to about 3.5 Wit]l the aid o Na~ 30% by wt.), 20 parts o Imhyclrolysed
vinyl acetate alld S0 parts of ~ethyl acrylate were adcLed together and the
~olymerization pcrformed in an at~nosp]lere of ni~rogen. The results expressed
~0 as percentages of stable aggregates obtailled in a clayey soil using -the
re~ulting graft poly~er wers as ollows:
13
Stable Aggre~tes by wet sieving
(larger tll~n Q.1 mm)
O. 1o l~y ~t of soil
Ih~llydro1ysed 62.7
50~0 hydro1ysecl 61.2
lOO`'o llydro1ysecl 69.2
lc fi
rile e,Yperimellt as in Ixcamp1e 1 was repeated using the sa~ne amoullt
oE cxude 1igllosu1fon.1te a~d ~ap wat~r. Su'~setlur-~ntly 50 p~rts of acrylic
acicl were addecl cand po1ymeri~ecl. 'Mlis was ~ollowed by an acldi-ticnal ~()
parts of vinyl cyanide ancl po1ymerized. The Imhydrolysed p~ocluct obtnined,
was tested fc~r soil caggregates orlllation (wet sieving larger t~an ~.1 r,lm)
al-cl Eo~tlld to ~ive 5~.9'0 st~1e aggreC~ates whell app1ied a~ 0.1~u by ~t oE
l!i tl~o soil.
T:xt~ple 7
100 parts of crude 1ignosu1~onate were introducod in~o a reactor
(provided witll a stirrer~ a t]lerr~lorlleter and a condenser) togeth&r with lS0par-ts of tap water. I~fter tlr~lt S0 parts of me~lly1 acrylate and 50 parts
o styrene were introducecl illtO the reactor ancl-the mixture heated -to
about 50C. Tl~en ~ parts o~ hydrogen peroxicle (10~o `by vol~me) were added
and an exotllermic reaction was observed. In order to assure tile co]n~)lete
cons~nption of the monomerJ the mixture was heated at 95 - 96C for ten
minutes. The product ob-tainr-~d appeared as a mill~y dispersion. AFter
2S llyclrolysis t50~o of the es~ers groups) the produc~ was ~ound to ~e usecul
for surace stabi1ization of sand a~aillst wind erosion.
^,~
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