----..---__ . . . . . . - - . .“. ...
----..---__ . . . . . .
-
- .
.“.
II.
- .
<..
-
.*
-
-
-
1 . INTRODUCTION
Reclamation of
salr-affectea
SO!LlS,
i.n ordar t;c; ~ILCI-.G- çe
h “L_
agricultural
production.
requires
good
unàerstanding
-
02 niLi:n
phenomena that may occur in the fizld.
The low soi1
fertility (nirrogen 2nd phosphorus! dnd t:hk;
high osmotic potential duo to the Salt CO~3C~~t~liCiO~l Li?e Cil0 ni;LiI?
difficulties of
saliri "OilS
recla;nation.
rjtJ,Ja-Qçe of ty,qYi; f;c-
tors , plants cannot uptakz enough
nutlients from
*[si;.2 ÇGiL &:"?(Ly!
they are available.
Resaarches vn
trie principlns
sali: ar1ù
I+)d -[ 2 **- ~yri~~j)i,~Ç i;[itcJ
soi1 cari help to
crops
yields
in,provrnent,
in
rhiir
cü3jw 56IllE
researches bave teen carried out in laboratory and the iield. Irs
CGIiCi2S mainly stilaction of sait toleranir
foret trees,
dJtift-;L- bü-
liiI3Ce
under
plantation,
Salt-affected
soils afforestution ~nd
s;< tolzrant Rhizobiurn ând Frünkia strains select,ion-
Using high sait tolerant trees should likely to bu important
way of
Salt-affected soilu
reclamation, MicrobioIclgical and nu-
clear tecnnics should give great help to improve plant adaptation
and growth mecanismu in säl.ine soils.
2.RESEARCHES PL&NED FOR THE TWJ FIRST YEARS
Durring
rhe
pariode,
fl?Glll
january
1 g 6 7 to january 1989,
works hereaftar designated were carried out:
- Studies of trees sa1.t rulerancc: grc-nhouse
and Ïiéid ex-
periments:
- Frankia and Rhizobitirn strainç isolation:
- Selecting high nitroyen-fixing and sait tolarant scraihs;
- NitrOgC?ll fixation potential in szilinz conditions;
- Water balance stuciy;
- Soi1 salicity chanying undsr fori-st plantaticn:
- Saline -oils ûffor~~sf-a~oiorL;
- Ecophysiology studio-;:
sap potential mesurniehts.
$It>ÇiI Gf
j-héçeç Li t l.lù i t= S StEL'tt:èCJ during 111.:~: tii.rYt yt~iir. E./i;.ilo
othars üre ju%t 5tdrtC3.
3.FOREST TREES SALT TOLERANCE STUDIES
3.1.PRELIMINARY STUDIES
Forest tr2es salt talerance
studio;,
hSV8
started
in 1585
with
experiences
us in-[
watering
çyçi-em
with
saline wùtai in
greenhouse. The resulrs
showed high r*sisranca
lC?VC+l
Cif SOiliY
SpeCieS
ay
Casuarina
5:;&setif,>lia,
Mclbl.euca
ïcucadel~ldran,
M.leucadendron and
Prosopis
juliflora;
Whll62
others
âs EU(-lâ-
lyptus camaldulensiu and Albizia
lebbek are sensitive:. The most:
tolerant cdn grow well until an elcctri.c:al conductivirL7
0 f 3 zjns -
/cm and
tkie sentivti
ç p ecz ri. 8 s d i e d
sit an eloccric~al conductivl:~
more thon 2Gins/ciii.
Graphies 1 and 2 shaw growth of Casuarina
equi czej-i:foJja UC-
cording to salinity level.
In order to 'transfdz
l~boï.&toq
ye2uj.ty -jnj-0 Li+.al(-j ç~p,c;
plantation triôls bave been done in situ with
dirftirenc kinils uf
species on two Types of s&ïinti soi.15:
- Sandy soi1
: electrical conductivity = l.G-3,Cmr;/cm;
- Sand loamy soil: electrical conductivity < 1,5ms/crii;
.
.
‘.
*,
.*
.
.
.
.
.
- Sand lodmy soil: electrical condtictiviry - 1.0-2,Yms/cm;
- Clzyed soi1
: electrical conductiviry ul. 5Hl5//in;
- Clayed sui1
: electrical conductivity = 1 a 5-*i!ns/on..
These soila are locared in two difftirenc e;ittJs; on& nkTIr Si-
ne river which bas sandy soi1 with thre
salinity levels
i::1-; rh-1:
other one
near smali
crick of Saloum rivër with others ty~us of
soils.Results obtzined from these triais corrt-3spor.d to rhose *rcct
greenhouse experiences.
Citsuarina is If\\i3're rp.sist;inc t'r;&n &ïbizii
which is very sensitive up to
2ms/cm of
soiï electricsl cGt;ti.ic-
tivity. The
msan heighr
of Casuarina, 2 years afttir plantarlon,
is 3E;Ocm in sdndy soi1 at E.C ( 2.5rnu/cm and
27Ocm at E.~i4~i,s/cm
and 2dûcm at %.C>4ms/cm in clayed soil.
3.2.SEE1) GERMINATION TESTS QN SALINE CGlr'L)ITIONS
Knowinq
Salt
influence
or, forest rreec; speds yerif,irLatior,,
expriences suin two types
of substrats
(hydrophylle cotton ~nd
Sand loamy
soiï) are
done in
the laboratcr~
[‘.>i'c)k fs;-‘r sptyi&a.L&
trees saeds: Casuarina equisetifolia,
mcailyp LUS microthe~ü, kle-
laleuca leucadendron and Et!. acacioides,
3.2.1.SEEDS GERt~INATICN 08 HYCRQFHYLLE COTTON
3.2.1.1.Experience methodology
Hydr~phyllt~
cotton is
used
a5
saedbed, layed ork plastic
bowls on which lg of forest rrees szeds ,%re puted on. The cotton
was wat teci
with water of three treatmtir,.t;: frcsh t:TiK.i?r (E.CtO,CL
ms/cm) s saiine water with E.C = 2msjcm und süline wcnter
E~lit11 E.C
= 5ms/cm.
During the a11 exprience period, the cotton was ~sttçr:~ de;ily
with the different solutions
by injection
with seringae (?&nl) .
Experience took 14 days in laboracory inside <*tuva ât l-ei.;,~er~turc
of 25oc.
3.2.1.2,Results
Three
days
after
experiencc
starttL!d,
gcrmrnalio~;
;J,$s
observed in a11 bowls. Milci+~ cïas also vbserv*d t.i--.n dbys aT1-er an
Eucalyptus and Casuarina in a11 rreatmentz and on
Meî.~llet.~c:l &Ca-
cioides only in treatment with fresh water.
Table 1
belon shows the quantity per gramme of seeds cJarmi-
nated 14 days after.
Table 1 : Germinated stedu per lg alter 14 days,
Casuarina equisetifolia
209
:z IJ 0
1 y' 2
Eucalyptus microrheca
531
569
J?[ 3
blolaeluca viridiflora
bb%
8 iJ 8
aio
Plelaleuca clcacioides
698
4 E; fj
906
I;Je cari 538 from
this table
variatl.on of
seeds g;-rrniiniitïon
accordiny to treatments and SpsCieS.
In general
case the results show that germination is bat-ter
2
I
with saline water than with fresh wdter.
Comparison betwezn trearment To and others sho~7s:
- Casuarina gives its test germination in
treatment Ti tiith
14.842 more. Tt decreases cit T2 with 17.7C% li;ss.
- Eucalyptus microthtica
CJX-ObJS Wkdl
in 'I'l and T2 without no
sigcificant differencs between both, with respactivzly
7.16Y and
7.34% more.
- halaleuca viridiflora. CjiVSS its
best restilts
in T2 with
6.1% more than in To.
- Melaleuca acacioidtis givss irs
bast
rosults
i n
Tl with
41.20% more than in TO and devreascs in T2,
This means
for a11 s2ccies seeds germin&rion i.ncre;:ses with
sait solution concentration unntil
a certain
level at
whicL i t
decrcases again.
Prescnce of sal-t in the solution must stimulate
seeds germination üp to a certain lfivel of
salinity àepending on
specy .
3.2.2.SEEDS GERMINATION OH SOIL SUUSTRAT
3.2.2.1.Exgerience I?lEtthOdQlGgy
Forest
Cs=GVS
sccds
ge.rminating was exptrimented also wirh
soi1 as bedseed. The soiL \\zhic;ii
h:ks been
uscd was a sand loamy
soi1 containing lass
15L 02 cl~ry' and bout 1% of orgnnie carbon.
Six garmination
j-J(y&&S
WT,IYT: filds:ci with this S:oi. L on r~hich
se.zds
Qf
Casuarina
quisetifolia,
Eucalyptus
microtheca,
Malaleuca leucadendron and M. acacioidaa are so:;ed. Each gtirK\\ina-
tion box is about 5Ocm wide and 1OOcm long.
According to specy, diiferent quantifies ot seeds trere ustid:
39 for CasuarinA, 2~; for Eucalyptus and 0.5g for M~lnleucr;.
Three tre2trnens.s
wtim applied for warering: fresh ~srt;r(To)
with E.CtO.O2ms/cm, saline water(T1) with E.C=2m/cm and 12 tijith
E.C=5ms/cm(2OoCj. Watar 'ilas appliad twice pvr &y dr 7 o~ciock in
the marning and 5 o'ocl~ck p.m by sprayir,g with handling sgra;r.
During the ail period
of exparience,
dieù g3rminated sci%ds
were daily
calculated. Total germinsted seed:~ were calculated at
the end of the exparience.
3.2.2.2.Results
Rive days after experience started, Eucalyptus seeds sthrred
to germinate
at To
and Tl.
C. qquiuetifolia tind M. acücj.oides
gerninated 3 days later at TO and '~1, while M. virîdiflors ycrmi-
nated at
TO 8
days and
â'c Tl
11 days
later. Witlr. T2 only Z.
microtheca and C. equisetifolia
germinated, respctively,
c3 ELild
10 dnys later. Melalbuca didnlr gesminate at this salinicy.
Table
2 below
shows
amounts
of sceds yerM.nated 75 d~ys
afrer according traatments.
Tüble 2 : Number of seeds germinated 75 duys after zccording
wârer salinity.
SPECIES
TREATMENT TO
TREk?'SIENï Tl
TREkl'iWï\\iT T2
E.C<.02ms,'cm
E . C = 211~s / cm
E.C=Jm3/cm
C. eyuisetifolia
835
5 5 4
137
E. microtheca
270
326
56
M. viridiflora
884
63
0
3
Table
3 :Gcrmiriated
szf-;As died number variation with time
according treatments.
C.eçui. .G
. O
.O
. O
.ci
io
4
7
4%
ï.2
1. 4
12
E.micro..O
. O
.O
d
7 1
44
16
7
CI _
L.lu
.o "3
.3
M.virid. 5 .O .O .O
13 .o .o .Fl
.O
.o
.tl
.o
M.acaci. 6 .O .O .O
4
.o .û *o
1
"0 .o .o
3 .2.3.D1 scus ‘SIOf;TS
Sceds germination dopends on thfz
su'bstrat
LlS6d as
ic bjas
bk:eri shoi;n
witil h~drolophylle cottcn ai--,d soil. :;oil substrat iji-
vcs normal tcndancy of secds yzrmination if c<e consiùer salinity
as limitlng
factor of
trocs grcwth. Differance obscrv2d betwtjen
hydrophylle cotkon anci soi.1 might ba thû f:3ct
of sait accumula-
tion into soi1 due to e'vaporution b.%caust3 thti ternpt~rztur," ouî-.sidc:
is abouc 340C during expzrio.;lct- period.
Ti;;n ~ith
sclil',t-
solut icz
the Salt content is highcr into soi1 than in hydrophyllc~ cotte-I,
3.3.SXLINC SOILS AFFORESTATION
3.3.1.EXPERIENCE NETHODOLOGY
In order
t0
understand bettur
salinit:? effect on forast
tracs growth, tri.51s of
fort=st plantations
utiïe carritz.d
out in
tha field.
Several forast spccias wr3re used as C. equissrifoliu,
C. glauca, C.
cuninghamians, P.
juliilorn, P.
chilensis, E.
microtheca, M.
viridiflosa and M. acacioides.
According to our
first results showing bad gro:jth of A. lebbtiir, ttis s~ecy ~a:~ ntt
USLYd for
rhe~ trialu,
be<+;2uaa .~,uc;ll other -f~;~t~r:~ I:i)-* ~>li\\~~;~c or
soi.1 physical properties ha,ve great on its growth.
Small plants of these
species weri:
introduced on diffsranr.
types of soi1 with different salinity level:
- Bloc 1:
Sar.tiy soil:
E,C =
0.5-1.5ms/cm(2OoCj of diluted
extract (1/5);
- bloc 2: Loam sandy soil: E.C = l.O-2.0ms/cm(20oC);
4
3.3.2.RESULTS
3.4.1. OBJECT IVEF
3.4,2.EXEERIENCE METHDDOLOGY
Wndarsthnding nitrogen i.niYlux-ic~ on sait toleL'ar;ce k.y foryst
trezs ,
experiexe usiCg poXs of lm3 capocity a~ poil con~ï~intr:;
ha3 bzen carried out in yrtitinhc>usr during f3~r monchs, frcsm IQrch
to July 1988. C. equisetifolia and P. juliflora were usad.
Five treatments
were applied
with four replicates, One pst
repres2nt one replicate.
- Treatment To : without nitrogen feïtilizer;
- Treatment Tl : 5g of Ureci per pot of 1~3;
- Treatment T2 : 1Og of Urea per pot c,f Im3;
- Treatment T3 : 15g of urea per pot of lJZ5;
- Treatment T4 : 2Oq of Ursa per pot- 0.C lm3.
Watering
solution
W&S
saline
Wh ter
with an
electrical
conductivity of 30ms/cm(2OoC). Each plat-AL or pot was wazered ttith
21 once per weak.
Measurements of height
and
phanologicti
os~5~rvations hzve
been every week. Leaves
and sm;ll
braxl&es i;r‘?
hasll fer bcing
analysed for minarals detarmination.
3.4.3.RESULTS
Three waeks after experience
starteü, a11
C3suariri.a plants
died in
a11 tceatmentu
wirh nitrogen. Prosopis showeci CO~~L: L;~X-
ptomaticul aspects as leaves fall and yello;ring, tut
became nur-
mal 2
wieks later.
During aIl
experi~~nc~~ period Prosopis giveù
good development.
The growth is better in T3 with 2.75 cm more
than the refe-
rdncc.
It decreases in
ï4.
This meilns that nitrogen prti~e~~e
stimulâtes plants growth in
saline
conditions
until
a cartain
salinity level
up to
that î.t hus no influence on its roler~n~s.
The limit amount SWVIS to "ne 15g pcr plants in li113 of svjl.
Table 5 beiow yives L~aves, root and branches
weight accor-
ding to treatments.
Table 5:
boles,
leavas,
roots and hr&nches fresh 2nd dry
matter weigth of P. juîiflcra according to treatments.
Plants
TO
Tl
T2
T3
ï dl
Dry aerian matter
30.7%
36.62
33.3%
34.62
3 &l . 3" ':. 1
Fresh lecrves
21.28;
21.2s
29.39
22.2;
19 . \\2 1;
Fresh boles
45.0:
4 9 . 4 '0
53.43
57 .$1;
53 . 7 !;-
Fresh roots
35.2:
31-S!&
2D.4~;
24.0'0
21.7u
Dry matter weight increases with nitrogen am5ui.t addtd into
soil. Treatments T2, T3
&nd T4
ara net difrerent. 'ï'rtii;tment T1
gives the best weight.
This means
that nitrogen
uptak2 is more
important if
the amount
of the festiliztr uueJ i-i not &xaoerli;tg
Jg.
The fresh leaves are more important weight in T2. Tt decrea-
ses in T3 and T4. This means that up to 2Og the fertilizer amount
used has an inverse
effect on
nitrogen uptake
in saline condi-
tions.Fresh tiges weighc increasas with the fertilizer amount up
to 15g from which it decreases. Treatment T3 used to he the .I.imi-
ting level. of nitrogen fertilizer using in saline conditions with
6
30ms/cm of electrical conductivity.
Fresh root taeight gives
-jnver.se pa~ul$-- I
It decrtiasi;s \\liitin
fertilizer amount incretis,-iTi. This that root ayste,n devai,zp;nent is
affected by nitrogen 3‘1.~4 't:-.biLity into soi.1.
4.FRANKIA AND RHIZOBIUM S':RAïNS iSGLZ;TItJi,;
4.1.METHODOLOGY
This study consist LQ
isolate
f :CClB
sûil
Frankia srr&ins
which bave high nirrogen porential fixation and sait tolerknt.
Saline soi1 samples were
taken from fielü ünder
fi3rc?ir plnnta-
rion. Soi1 salinity was about Ims/cm in extract of 1/5.
The samples are divided into 4 par:--s. Small ceramic pots are
used as soi1 conraincrs. Samples were srerilizrzd before tke:f &VIL-!
been used. Four treatmenrs tire applied:
- 1/4 saline soi1 f 3/4 non saline soil;
- 1/2 saline soi.1 + 1/2 non saline soil;
- 3/4 salina soi1 + 1/4 non saline soil;
- 4/4 saline soil.
Casuarina seeds
aïe sowed
in each Fat \\;irh Ïour rsplicates
per trearment.,
4.2,RESULTS
Germinated saeds decrease
when
proportion
ü f
s A i i na soi1
used is high. The
bzst gremination was Gbsarved in treatmezit Ti
and T2. Germination ratio is in
T3 $(-j-5~!~
crid in
T4 only about
20;. Nûne
O f thd
plants which gat developped by this exp<<rience
didn't nodulata, then no strain couldn'r ba isolated.
Rhizohium strains isolation gives
CjûRlE? ~EtSUltS. G<:TXin3tiO~~
was observed only in Tl threti wer;ks after.
In order
to find
out whar
is rhe main problam orhcr ez:sa-
riences have beïn started lacer on.
5,WATER BALANCE STUDIES UIDER FORES'i TREIS
Having good knowledgi! on water availability and ugt~kc undsr
forest plantation,
watsr balance
measurements studios have btjen
carriecl out in laboratory and in field.
S,l.GREENHOUSE EXPERIENCE
5.1.1.METHODOLOGY
Water balance measuremerits wore taken undar
Casuarina, Pro-
sopis and Melalauca trees of one yeav old. Trecs \\i:er~: planttid in
sïnall lysimeter of 4m3 of surface. Six plots
wtire used
of whoum
each one contains 4 plants.
Srnall neutron
access tubes
~ere inserted into soi1 on ezich
plot to a depth of 120~1~.
Once per week t-ha
trees wera
wutered with
salinE; iJutc?ï at
30ms/cm arid fresh watèr, For each s,->ecy +hr~"ë plots wc+re wjrarad
with saline water and throe others with frosh wiîter.
Experience startad Ori luovember 1987 and endcd on Msrch 1988.
c
*
5.1.2.RESULTS
Table 6 below givas water balance
Chùriging under Casuari%a,
Melaleuca and Prosopis pldhcs.
Table 6:
Fater b a l a n c e
chsnging
betweE;n 1~/12/07 and
conditie.1s.
DEPTH
SPECIES
3.4/12/97
0-15cm
c . cqui set .
pl. 1euca.d.
1/
2,'
P.juZff.
1 /'
2,i
15-3Ocm C. fquisct . l/
2/
M.lC?GTdd.
i/
2 /
P.julif.
1/
21
30-45cm c. aquiser . si
a/
IJJ.leLlcZZiù.
1/
2/
P.ju1i.f.
l/
2 /
45-60cfi1 C.eyuiset. 1. /
3 f
2. ,'
MI leucad .
31
21
P.ju1i.f.
1/
2,
.
c
Access tubes ~ere insert& inca soi1 near planç roots,
F'irsr results showed chat P;ater content changing within soi1
profil dti;pendv on the spcxy used and the soi.1 ty+-
ûttir COrlCi3ïiC
remzins usualy higher in cl.cIytid soi1 than in sz~xiy s-il. l'k sc‘il.
water content changing ic, du2 to t1*ces u~talrs
GPid evtporatiori ty
capiildry risirlg.
G.GENERAL CONCLUSION
Results obtuined
frorn a11
these experiences slxw important
intorests to continue studies on sait-afrectcd poils TO ~ske tham
more fertile.
To understand
better
sâlr infl.Jcnce
mecanisms on forest
treos many studies have to bc carriad C)I;L~ again in diffèrent ways
c.s Ghysiology, soi1 chemic zr,d phycic.
f&iiYi results
of ail
experiences which i;-nded kdill. be publi-
shed sep.3trcr t ly *
9
-
- .
.“.
II.
- .
<..
-
.*
-
-
-
1 . INTRODUCTION
Reclamation of
salr-affectea
SO!LlS,
i.n ordar t;c; ~ILCI-.G- çe
h “L_
agricultural
production.
requires
good
unàerstanding
-
02 niLi:n
phenomena that may occur in the fizld.
The low soi1
fertility (nirrogen 2nd phosphorus! dnd t:hk;
high osmotic potential duo to the Salt CO~3C~~t~liCiO~l Li?e Cil0 ni;LiI?
difficulties of
saliri "OilS
recla;nation.
rjtJ,Ja-Qçe of ty,qYi; f;c-
tors , plants cannot uptakz enough
nutlients from
*[si;.2 ÇGiL &:"?(Ly!
they are available.
Resaarches vn
trie principlns
sali: ar1ù
I+)d -[ 2 **- ~yri~~j)i,~Ç i;[itcJ
soi1 cari help to
crops
yields
in,provrnent,
in
rhiir
cü3jw 56IllE
researches bave teen carried out in laboratory and the iield. Irs
CGIiCi2S mainly stilaction of sait toleranir
foret trees,
dJtift-;L- bü-
liiI3Ce
under
plantation,
Salt-affected
soils afforestution ~nd
s;< tolzrant Rhizobiurn ând Frünkia strains select,ion-
Using high sait tolerant trees should likely to bu important
way of
Salt-affected soilu
reclamation, MicrobioIclgical and nu-
clear tecnnics should give great help to improve plant adaptation
and growth mecanismu in säl.ine soils.
2.RESEARCHES PL&NED FOR THE TWJ FIRST YEARS
Durring
rhe
pariode,
fl?Glll
january
1 g 6 7 to january 1989,
works hereaftar designated were carried out:
- Studies of trees sa1.t rulerancc: grc-nhouse
and Ïiéid ex-
periments:
- Frankia and Rhizobitirn strainç isolation:
- Selecting high nitroyen-fixing and sait tolarant scraihs;
- NitrOgC?ll fixation potential in szilinz conditions;
- Water balance stuciy;
- Soi1 salicity chanying undsr fori-st plantaticn:
- Saline -oils ûffor~~sf-a~oiorL;
- Ecophysiology studio-;:
sap potential mesurniehts.
$It>ÇiI Gf
j-héçeç Li t l.lù i t= S StEL'tt:èCJ during 111.:~: tii.rYt yt~iir. E./i;.ilo
othars üre ju%t 5tdrtC3.
3.FOREST TREES SALT TOLERANCE STUDIES
3.1.PRELIMINARY STUDIES
Forest tr2es salt talerance
studio;,
hSV8
started
in 1585
with
experiences
us in-[
watering
çyçi-em
with
saline wùtai in
greenhouse. The resulrs
showed high r*sisranca
lC?VC+l
Cif SOiliY
SpeCieS
ay
Casuarina
5:;&setif,>lia,
Mclbl.euca
ïcucadel~ldran,
M.leucadendron and
Prosopis
juliflora;
Whll62
others
âs EU(-lâ-
lyptus camaldulensiu and Albizia
lebbek are sensitive:. The most:
tolerant cdn grow well until an elcctri.c:al conductivirL7
0 f 3 zjns -
/cm and
tkie sentivti
ç p ecz ri. 8 s d i e d
sit an eloccric~al conductivl:~
more thon 2Gins/ciii.
Graphies 1 and 2 shaw growth of Casuarina
equi czej-i:foJja UC-
cording to salinity level.
In order to 'transfdz
l~boï.&toq
ye2uj.ty -jnj-0 Li+.al(-j ç~p,c;
plantation triôls bave been done in situ with
dirftirenc kinils uf
species on two Types of s&ïinti soi.15:
- Sandy soi1
: electrical conductivity = l.G-3,Cmr;/cm;
- Sand loamy soil: electrical conductivity < 1,5ms/crii;
.
.
‘.
*,
.*
.
.
.
.
.
- Sand lodmy soil: electrical condtictiviry - 1.0-2,Yms/cm;
- Clzyed soi1
: electrical conductiviry ul. 5Hl5//in;
- Clayed sui1
: electrical conductivity = 1 a 5-*i!ns/on..
These soila are locared in two difftirenc e;ittJs; on& nkTIr Si-
ne river which bas sandy soi1 with thre
salinity levels
i::1-; rh-1:
other one
near smali
crick of Saloum rivër with others ty~us of
soils.Results obtzined from these triais corrt-3spor.d to rhose *rcct
greenhouse experiences.
Citsuarina is If\\i3're rp.sist;inc t'r;&n &ïbizii
which is very sensitive up to
2ms/cm of
soiï electricsl cGt;ti.ic-
tivity. The
msan heighr
of Casuarina, 2 years afttir plantarlon,
is 3E;Ocm in sdndy soi1 at E.C ( 2.5rnu/cm and
27Ocm at E.~i4~i,s/cm
and 2dûcm at %.C>4ms/cm in clayed soil.
3.2.SEE1) GERMINATION TESTS QN SALINE CGlr'L)ITIONS
Knowinq
Salt
influence
or, forest rreec; speds yerif,irLatior,,
expriences suin two types
of substrats
(hydrophylle cotton ~nd
Sand loamy
soiï) are
done in
the laboratcr~
[‘.>i'c)k fs;-‘r sptyi&a.L&
trees saeds: Casuarina equisetifolia,
mcailyp LUS microthe~ü, kle-
laleuca leucadendron and Et!. acacioides,
3.2.1.SEEDS GERt~INATICN 08 HYCRQFHYLLE COTTON
3.2.1.1.Experience methodology
Hydr~phyllt~
cotton is
used
a5
saedbed, layed ork plastic
bowls on which lg of forest rrees szeds ,%re puted on. The cotton
was wat teci
with water of three treatmtir,.t;: frcsh t:TiK.i?r (E.CtO,CL
ms/cm) s saiine water with E.C = 2msjcm und süline wcnter
E~lit11 E.C
= 5ms/cm.
During the a11 exprience period, the cotton was ~sttçr:~ de;ily
with the different solutions
by injection
with seringae (?&nl) .
Experience took 14 days in laboracory inside <*tuva ât l-ei.;,~er~turc
of 25oc.
3.2.1.2,Results
Three
days
after
experiencc
starttL!d,
gcrmrnalio~;
;J,$s
observed in a11 bowls. Milci+~ cïas also vbserv*d t.i--.n dbys aT1-er an
Eucalyptus and Casuarina in a11 rreatmentz and on
Meî.~llet.~c:l &Ca-
cioides only in treatment with fresh water.
Table 1
belon shows the quantity per gramme of seeds cJarmi-
nated 14 days after.
Table 1 : Germinated stedu per lg alter 14 days,
Casuarina equisetifolia
209
:z IJ 0
1 y' 2
Eucalyptus microrheca
531
569
J?[ 3
blolaeluca viridiflora
bb%
8 iJ 8
aio
Plelaleuca clcacioides
698
4 E; fj
906
I;Je cari 538 from
this table
variatl.on of
seeds g;-rrniiniitïon
accordiny to treatments and SpsCieS.
In general
case the results show that germination is bat-ter
2
I
with saline water than with fresh wdter.
Comparison betwezn trearment To and others sho~7s:
- Casuarina gives its test germination in
treatment Ti tiith
14.842 more. Tt decreases cit T2 with 17.7C% li;ss.
- Eucalyptus microthtica
CJX-ObJS Wkdl
in 'I'l and T2 without no
sigcificant differencs between both, with respactivzly
7.16Y and
7.34% more.
- halaleuca viridiflora. CjiVSS its
best restilts
in T2 with
6.1% more than in To.
- Melaleuca acacioidtis givss irs
bast
rosults
i n
Tl with
41.20% more than in TO and devreascs in T2,
This means
for a11 s2ccies seeds germin&rion i.ncre;:ses with
sait solution concentration unntil
a certain
level at
whicL i t
decrcases again.
Prescnce of sal-t in the solution must stimulate
seeds germination üp to a certain lfivel of
salinity àepending on
specy .
3.2.2.SEEDS GERMINATION OH SOIL SUUSTRAT
3.2.2.1.Exgerience I?lEtthOdQlGgy
Forest
Cs=GVS
sccds
ge.rminating was exptrimented also wirh
soi1 as bedseed. The soiL \\zhic;ii
h:ks been
uscd was a sand loamy
soi1 containing lass
15L 02 cl~ry' and bout 1% of orgnnie carbon.
Six garmination
j-J(y&&S
WT,IYT: filds:ci with this S:oi. L on r~hich
se.zds
Qf
Casuarina
quisetifolia,
Eucalyptus
microtheca,
Malaleuca leucadendron and M. acacioidaa are so:;ed. Each gtirK\\ina-
tion box is about 5Ocm wide and 1OOcm long.
According to specy, diiferent quantifies ot seeds trere ustid:
39 for CasuarinA, 2~; for Eucalyptus and 0.5g for M~lnleucr;.
Three tre2trnens.s
wtim applied for warering: fresh ~srt;r(To)
with E.CtO.O2ms/cm, saline water(T1) with E.C=2m/cm and 12 tijith
E.C=5ms/cm(2OoCj. Watar 'ilas appliad twice pvr &y dr 7 o~ciock in
the marning and 5 o'ocl~ck p.m by sprayir,g with handling sgra;r.
During the ail period
of exparience,
dieù g3rminated sci%ds
were daily
calculated. Total germinsted seed:~ were calculated at
the end of the exparience.
3.2.2.2.Results
Rive days after experience started, Eucalyptus seeds sthrred
to germinate
at To
and Tl.
C. qquiuetifolia tind M. acücj.oides
gerninated 3 days later at TO and '~1, while M. virîdiflors ycrmi-
nated at
TO 8
days and
â'c Tl
11 days
later. Witlr. T2 only Z.
microtheca and C. equisetifolia
germinated, respctively,
c3 ELild
10 dnys later. Melalbuca didnlr gesminate at this salinicy.
Table
2 below
shows
amounts
of sceds yerM.nated 75 d~ys
afrer according traatments.
Tüble 2 : Number of seeds germinated 75 duys after zccording
wârer salinity.
SPECIES
TREATMENT TO
TREk?'SIENï Tl
TREkl'iWï\\iT T2
E.C<.02ms,'cm
E . C = 211~s / cm
E.C=Jm3/cm
C. eyuisetifolia
835
5 5 4
137
E. microtheca
270
326
56
M. viridiflora
884
63
0
3
Table
3 :Gcrmiriated
szf-;As died number variation with time
according treatments.
C.eçui. .G
. O
.O
. O
.ci
io
4
7
4%
ï.2
1. 4
12
E.micro..O
. O
.O
d
7 1
44
16
7
CI _
L.lu
.o "3
.3
M.virid. 5 .O .O .O
13 .o .o .Fl
.O
.o
.tl
.o
M.acaci. 6 .O .O .O
4
.o .û *o
1
"0 .o .o
3 .2.3.D1 scus ‘SIOf;TS
Sceds germination dopends on thfz
su'bstrat
LlS6d as
ic bjas
bk:eri shoi;n
witil h~drolophylle cottcn ai--,d soil. :;oil substrat iji-
vcs normal tcndancy of secds yzrmination if c<e consiùer salinity
as limitlng
factor of
trocs grcwth. Differance obscrv2d betwtjen
hydrophylle cotkon anci soi.1 might ba thû f:3ct
of sait accumula-
tion into soi1 due to e'vaporution b.%caust3 thti ternpt~rztur," ouî-.sidc:
is abouc 340C during expzrio.;lct- period.
Ti;;n ~ith
sclil',t-
solut icz
the Salt content is highcr into soi1 than in hydrophyllc~ cotte-I,
3.3.SXLINC SOILS AFFORESTATION
3.3.1.EXPERIENCE NETHODOLOGY
In order
t0
understand bettur
salinit:? effect on forast
tracs growth, tri.51s of
fort=st plantations
utiïe carritz.d
out in
tha field.
Several forast spccias wr3re used as C. equissrifoliu,
C. glauca, C.
cuninghamians, P.
juliilorn, P.
chilensis, E.
microtheca, M.
viridiflosa and M. acacioides.
According to our
first results showing bad gro:jth of A. lebbtiir, ttis s~ecy ~a:~ ntt
USLYd for
rhe~ trialu,
be<+;2uaa .~,uc;ll other -f~;~t~r:~ I:i)-* ~>li\\~~;~c or
soi.1 physical properties ha,ve great on its growth.
Small plants of these
species weri:
introduced on diffsranr.
types of soi1 with different salinity level:
- Bloc 1:
Sar.tiy soil:
E,C =
0.5-1.5ms/cm(2OoCj of diluted
extract (1/5);
- bloc 2: Loam sandy soil: E.C = l.O-2.0ms/cm(20oC);
4
3.3.2.RESULTS
3.4.1. OBJECT IVEF
3.4,2.EXEERIENCE METHDDOLOGY
Wndarsthnding nitrogen i.niYlux-ic~ on sait toleL'ar;ce k.y foryst
trezs ,
experiexe usiCg poXs of lm3 capocity a~ poil con~ï~intr:;
ha3 bzen carried out in yrtitinhc>usr during f3~r monchs, frcsm IQrch
to July 1988. C. equisetifolia and P. juliflora were usad.
Five treatments
were applied
with four replicates, One pst
repres2nt one replicate.
- Treatment To : without nitrogen feïtilizer;
- Treatment Tl : 5g of Ureci per pot of 1~3;
- Treatment T2 : 1Og of Urea per pot c,f Im3;
- Treatment T3 : 15g of urea per pot of lJZ5;
- Treatment T4 : 2Oq of Ursa per pot- 0.C lm3.
Watering
solution
W&S
saline
Wh ter
with an
electrical
conductivity of 30ms/cm(2OoC). Each plat-AL or pot was wazered ttith
21 once per weak.
Measurements of height
and
phanologicti
os~5~rvations hzve
been every week. Leaves
and sm;ll
braxl&es i;r‘?
hasll fer bcing
analysed for minarals detarmination.
3.4.3.RESULTS
Three waeks after experience
starteü, a11
C3suariri.a plants
died in
a11 tceatmentu
wirh nitrogen. Prosopis showeci CO~~L: L;~X-
ptomaticul aspects as leaves fall and yello;ring, tut
became nur-
mal 2
wieks later.
During aIl
experi~~nc~~ period Prosopis giveù
good development.
The growth is better in T3 with 2.75 cm more
than the refe-
rdncc.
It decreases in
ï4.
This meilns that nitrogen prti~e~~e
stimulâtes plants growth in
saline
conditions
until
a cartain
salinity level
up to
that î.t hus no influence on its roler~n~s.
The limit amount SWVIS to "ne 15g pcr plants in li113 of svjl.
Table 5 beiow yives L~aves, root and branches
weight accor-
ding to treatments.
Table 5:
boles,
leavas,
roots and hr&nches fresh 2nd dry
matter weigth of P. juîiflcra according to treatments.
Plants
TO
Tl
T2
T3
ï dl
Dry aerian matter
30.7%
36.62
33.3%
34.62
3 &l . 3" ':. 1
Fresh lecrves
21.28;
21.2s
29.39
22.2;
19 . \\2 1;
Fresh boles
45.0:
4 9 . 4 '0
53.43
57 .$1;
53 . 7 !;-
Fresh roots
35.2:
31-S!&
2D.4~;
24.0'0
21.7u
Dry matter weight increases with nitrogen am5ui.t addtd into
soil. Treatments T2, T3
&nd T4
ara net difrerent. 'ï'rtii;tment T1
gives the best weight.
This means
that nitrogen
uptak2 is more
important if
the amount
of the festiliztr uueJ i-i not &xaoerli;tg
Jg.
The fresh leaves are more important weight in T2. Tt decrea-
ses in T3 and T4. This means that up to 2Og the fertilizer amount
used has an inverse
effect on
nitrogen uptake
in saline condi-
tions.Fresh tiges weighc increasas with the fertilizer amount up
to 15g from which it decreases. Treatment T3 used to he the .I.imi-
ting level. of nitrogen fertilizer using in saline conditions with
6
30ms/cm of electrical conductivity.
Fresh root taeight gives
-jnver.se pa~ul$-- I
It decrtiasi;s \\liitin
fertilizer amount incretis,-iTi. This that root ayste,n devai,zp;nent is
affected by nitrogen 3‘1.~4 't:-.biLity into soi.1.
4.FRANKIA AND RHIZOBIUM S':RAïNS iSGLZ;TItJi,;
4.1.METHODOLOGY
This study consist LQ
isolate
f :CClB
sûil
Frankia srr&ins
which bave high nirrogen porential fixation and sait tolerknt.
Saline soi1 samples were
taken from fielü ünder
fi3rc?ir plnnta-
rion. Soi1 salinity was about Ims/cm in extract of 1/5.
The samples are divided into 4 par:--s. Small ceramic pots are
used as soi1 conraincrs. Samples were srerilizrzd before tke:f &VIL-!
been used. Four treatmenrs tire applied:
- 1/4 saline soi1 f 3/4 non saline soil;
- 1/2 saline soi.1 + 1/2 non saline soil;
- 3/4 salina soi1 + 1/4 non saline soil;
- 4/4 saline soil.
Casuarina seeds
aïe sowed
in each Fat \\;irh Ïour rsplicates
per trearment.,
4.2,RESULTS
Germinated saeds decrease
when
proportion
ü f
s A i i na soi1
used is high. The
bzst gremination was Gbsarved in treatmezit Ti
and T2. Germination ratio is in
T3 $(-j-5~!~
crid in
T4 only about
20;. Nûne
O f thd
plants which gat developped by this exp<<rience
didn't nodulata, then no strain couldn'r ba isolated.
Rhizohium strains isolation gives
CjûRlE? ~EtSUltS. G<:TXin3tiO~~
was observed only in Tl threti wer;ks after.
In order
to find
out whar
is rhe main problam orhcr ez:sa-
riences have beïn started lacer on.
5,WATER BALANCE STUDIES UIDER FORES'i TREIS
Having good knowledgi! on water availability and ugt~kc undsr
forest plantation,
watsr balance
measurements studios have btjen
carriecl out in laboratory and in field.
S,l.GREENHOUSE EXPERIENCE
5.1.1.METHODOLOGY
Water balance measuremerits wore taken undar
Casuarina, Pro-
sopis and Melalauca trees of one yeav old. Trecs \\i:er~: planttid in
sïnall lysimeter of 4m3 of surface. Six plots
wtire used
of whoum
each one contains 4 plants.
Srnall neutron
access tubes
~ere inserted into soi1 on ezich
plot to a depth of 120~1~.
Once per week t-ha
trees wera
wutered with
salinE; iJutc?ï at
30ms/cm arid fresh watèr, For each s,->ecy +hr~"ë plots wc+re wjrarad
with saline water and throe others with frosh wiîter.
Experience startad Ori luovember 1987 and endcd on Msrch 1988.
c
*
5.1.2.RESULTS
Table 6 below givas water balance
Chùriging under Casuari%a,
Melaleuca and Prosopis pldhcs.
Table 6:
Fater b a l a n c e
chsnging
betweE;n 1~/12/07 and
conditie.1s.
DEPTH
SPECIES
3.4/12/97
0-15cm
c . cqui set .
pl. 1euca.d.
1/
2,'
P.juZff.
1 /'
2,i
15-3Ocm C. fquisct . l/
2/
M.lC?GTdd.
i/
2 /
P.julif.
1/
21
30-45cm c. aquiser . si
a/
IJJ.leLlcZZiù.
1/
2/
P.ju1i.f.
l/
2 /
45-60cfi1 C.eyuiset. 1. /
3 f
2. ,'
MI leucad .
31
21
P.ju1i.f.
1/
2,
.
c
Access tubes ~ere insert& inca soi1 near planç roots,
F'irsr results showed chat P;ater content changing within soi1
profil dti;pendv on the spcxy used and the soi.1 ty+-
ûttir COrlCi3ïiC
remzins usualy higher in cl.cIytid soi1 than in sz~xiy s-il. l'k sc‘il.
water content changing ic, du2 to t1*ces u~talrs
GPid evtporatiori ty
capiildry risirlg.
G.GENERAL CONCLUSION
Results obtuined
frorn a11
these experiences slxw important
intorests to continue studies on sait-afrectcd poils TO ~ske tham
more fertile.
To understand
better
sâlr infl.Jcnce
mecanisms on forest
treos many studies have to bc carriad C)I;L~ again in diffèrent ways
c.s Ghysiology, soi1 chemic zr,d phycic.
f&iiYi results
of ail
experiences which i;-nded kdill. be publi-
shed sep.3trcr t ly *
9