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Qun l Ngun Ti nguyn Thin nhin vng ven bin tnh Sc Trng
Hng dn k thut gieo m mt s loi cy ngp mn
Hong Vn Thi v Phm Trng Thnh
c xut bn bi
Deutsche Gesellschaft fr Internationale Zusammenarbeit (GIZ) GmbH
D n Qun l Ngun Ti nguyn Thin nhin vng ven bin tnh Sc Trng
Tc gi
Hong Vn Thi v Phm Trng Thnh
nh minh ha ba
L Trng Hi v Trn Huy Mnh
giz, thng 2 nm 2012
Hng dn k thut gieo m mt s loi cy ngp mn
Hong Vn Thi v Phm Trng Thnh
Thng 2 nm 2012
ii
Gii thiu v GIZ
Nng lc ton din cho pht trin bn vng
Cc dch v do T chc Hp tc Pht trin c (GIZ) cung cp to ra nhng gi tr kin thc v k
thut xuyn quc gia cng nh nhng k nng v qun l c th nghim v kim chng. L mt t
chc trc thuc Nh nc Cng ha lin bang c, GIZ h tr Chnh ph c trong nhng n lc thc
hin cc mc tiu trong lnh vc hp tc quc t cho pht trin bn vng. GIZ cng tham gia vo cng
tc gio dc quc t trn ton cu.
Thit k cc dch v theo yu cu
GIZ cung cp cc dch v hiu qu c thit k ph hp vi yu cu ca pht trin bn vng. Nhm
m bo s tham gia ca tt c cc bn lin quan, GIZ p dng phng php tip cn tng th da trn
cc gi tr v nguyn tc c ng h trong x hi c. y l cch m GIZ to thun li cho s thay
i v trao quyn cho ngi dn lm ch cc quy trnh pht trin bn vng ca ring h. Khi thc hin
iu ny, GIZ lun cao s mnh pht trin bn vng l nh hng ch o xuyn sut trong mi hot
ng ca t chc v lun quan tm n cc yu t kinh t, x hi v sinh thi. GIZ h tr cc i tc cp
a phng, khu vc, quc gia v quc t trong qu trnh thit k cc chin lc v p ng cc mc
tiu chnh sch ca h.
a ra cc gii php pht trin
GIZ hot ng trn nhiu lnh vc: pht trin kinh t v xc tin vic lm; xy dng nh nc v khuyn
khch dn ch; thc y ha bnh, an ninh, ti thit v gii quyt mu thun dn s; an ninh lng thc, y
t, gio dc ph cp; bo v mi trng, bo tn ti nguyn v gim thiu bin i kh hu. GIZ cng
cung cp cc dch v v qun l v hu cn, v ng vai tr l mt t chc trung gian gip cn bng cc
li ch khc nhau trong nhng bi cnh nhy cm. Trong cc tnh hung khng hong, GIZ cn tin hnh
cc chng trnh t nn v cu tr khn cp. L mt phn ca dch v pht trin, GIZ ng thi cung cp
nhiu chuyn gia h tr pht trin cho cc nc i tc.
Thng qua cc chng trnh dnh cho chuyn gia ha nhp v chuyn gia hi hng, GIZ gii thiu cc
cn b qun l v chuyn mn vo nhng v tr ch cht ti cc nc i tc. GIZ cng ng thi thc
y mng li hp tc v i thoi gia cc bn lin quan trong hp tc quc t. Nng cao nng lc cho
chuyn gia ca cc nc i tc l mt phn quan trng trong dch v ca GIZ, v chng ti to nhiu c
hi cho cc thnh vin tham gia cc hot ng c th duy tr v thc y nhng mi qua h m h to
dng c. Ngoi ra, GIZ cn to iu kin nhng ngi tr tui nng cao kinh nghim chuyn mn
ca mnh trn khp th gii thng qua cc chng trnh trao i dnh cho chuyn gia tr, qua gip h
t nn mng cho s nghip thnh cng trn cc th trng trong nc v quc t.
Cc c quan y nhim cho GIZ
Hu ht cc hot ng ca GIZ c thc hin theo y nhim ca B Hp tc Kinh t v Pht trin Lin
bang c (BMZ). Ngoi ra, GIZ cng hot ng thay mt cho cc B khc ca Lin bang c bao gm
B Ngoi giao, B Mi trng, Bo tn Thin nhin v An ton Ht nhn, B Quc phng, B Kinh t v
Cng ngh v B Gio dc v Nghin cu cng nh chnh quyn cc bang v c quan cng quyn
khc ca c, c quan v t chc thuc khu vc nh nc, t nhn trong v ngoi nc c, y ban
Chu u, Lin Hp Quc v Ngn hng Th gii. Chng ti hp tc cht ch vi khu vc t nhn v
thc y s hp lc gia cc lnh vc pht trin v ngoi thng. Kinh nghim ng k ca chng ti t
cc mng li ti cc quc gia i tc v ti c l yu t ch cht cho hp tc quc t thnh cng,
khng ch trong lnh vc thng mi, nghin cu v v vn ha m cn trong x hi dn s.
Phm vi ton cu GIZ v nhng con s
GIZ hot ng ti hn 130 quc gia trn ton th gii. Ti c, GIZ c mt hu ht cc bang vi vn phng chnh c t ti Bonn v Eschborn. GIZ tuyn dng trn 17.000 nhn vin trn ton cu vi khong 70% l nhn vin bn a. Ngoi ra, GIZ cn gii thiu hoc cp kinh ph cho khong 1.100 chuyn gia h tr pht trin, 700 chuyn gia ha nhp, 455 chuyn gia hi hng v 820 tnh nguyn vin (weltwaerts). Vi ngn sch thng mi khong 1,85 t Euro, GIZ c th t tin p ng c nhng thch thc ca tng lai.
iii
Li ta
D n Qun l ngun ti nguyn thin nhin vng ven bin tnh Sc Trng nhm mc ch bo v v s
dng bn vng t ngp nc ven bin v li ch ca ngi dn. Khi phc v trng mi rng ngp mn
s gp phn quan trng t c mc tiu ny bi v rng ngp mn bo v b bin khi xi l, bo
v l lt v l ni nui dng con non, ni c tr v ngun cung cp thc n cho nhiu loi thy sn m
sinh k ca nhiu ngi dn ph thuc vo .
h tr Chi Cc Kim Lm trong vic khi phc v qun l ton din rng ngp mn, d n bin
son hng dn k thut ton din v qun l rng ngp mn bao gm k thut gieo m, trng, chm
sc, bo v v gim st trong ba hng dn k thut ring bit v mt bo co chi tit v lch s rng
ngp mn Sc Trng t nm 1965.
Ti liu Hng dn k thut gieo m mt s loi cy rng ngp mn l mt ng gp quan trng cho
vic khi phc v trng mi thnh cng rng ngp mn bi v s thnh cng ca cng tc trng rng
ph thuc mc ln vo cht lng cy ging c trng.
Hng dn k thut ny do ng Hong Vn Thi (Phn vin Nghin cu Khoa hc Lm nghip Nam b,
Tp H Ch Minh) v Tin s Phm Trng Thnh (Phn vin iu tra Quy hoch Rng Nam b, Tp H Ch
Minh) bin son. Tin s Norman Duke, i hc Queensland, Australia, xem li ton din hng dn
k thut ny.
Hnh ba do ng L Trng Hi (i hc Kin trc, Tp H Ch Minh) v ng Trn Huy Mnh (Phn vin
iu tra Quy hoch Rng Nam b, Tp H Ch Minh) minh ha.
Hng dn k thut ny c dnh cho s dng ca cn b Chi Cc Kim lm v nng dn tham gia
vo vic qun l vn m cy rng ngp mn ng bng sng Cu Long v vng ven bin Vit
Nam.
Klaus Schmitt
C Vn Trng
iv
Mc lc
Gii thiu v GIZ ..........................................................................................................................................ii
Li ta .........................................................................................................................................................iii
Mc lc ....................................................................................................................................................... iv
Danh sch bng ...........................................................................................................................................v
Danh sch hnh ............................................................................................................................................v
Nhng k hiu, ch vit tt ...................................................................................................................... vi
1 Gii thiu ..............................................................................................................................................7
2 S cn thit phi xy dng cc vn m ......................................................................................8
3 Cc dng vm m ..........................................................................................................................9
4 Chn la lp a xy dng vn m ...................................................................................... 10
5 Thit k vn m ........................................................................................................................... 11
5.1 Vn m chm .................................................................................................................... 12
5.2 Vn m ni ....................................................................................................................... 13
6 La chn loi cy trng rng thch ng vi cc dng lp a..................................................... 14
6.1 Thu hi tri ging v tr mm ................................................................................................ 14
6.2 Nhn bit tri chn .................................................................................................................. 15
6.3 La chn loi cy ngp mn trng rng ................................................................................ 15
6.3.1 Bn chua (Sonneratia caseolaris (L.) Engl.) ........................................................... 15
6.3.2 Mm bin (Avicennia marina (Forssk.) Vierh.) ....................................................... 15
6.3.3 c (Rhizophora apiculata Bl.)/ ng (Rhizophora mucronata Lamk.) .............. 15
6.3.4 Cc vng/Cc trng (Lumnitzera racemosa Willd.) ................................................ 16
6.3.5 D vi (Ceriops tagal (Perr.) C.B. Rob.) ................................................................ 16
7 K thut gieo m cy con ti bu ................................................................................................. 17
7.1 Chun b t ........................................................................................................................... 17
7.2 Chun b lp m cy ............................................................................................................ 17
7.3 To Bu .................................................................................................................................. 17
7.4 Xp bu vo lp m cy ....................................................................................................... 18
7.5 Gieo ht, cy cy m, tr mm vo bu ................................................................................ 18
7.6 Chm sc cy m trong vn ............................................................................................. 18
8 K thut sn xut cy con r trn .................................................................................................... 19
8.1 Chun b t gieo m .......................................................................................................... 19
8.2 Gieo ht .................................................................................................................................. 19
8.3 Chm sc cy con ................................................................................................................. 19
9 K thut sn xut mt s loi cy ngp mn ................................................................................. 20
9.1 Bn chua (Sonneratia caseolaris (L.) Engl.) .......................................................................... 22
9.1.1 Thu hi, bo qun v ch bin ht ging ............................................................... 22
9.1.2 Sn xut cy con trong bu .................................................................................... 23
9.1.3 Sn xut cy m r trn ....................................................................................... 23
v
9.2. Mm bin (Avicennia marina (Forssk.) Vierh.) ...................................................................... 24
9.2.1 Thu hi, bo qun v ch bin ht ging ............................................................... 24
9.2.2 Cy cy vo bu ..................................................................................................... 25
9.2.3 Chm sc cy m trong vn ............................................................................. 25
9.2.4 Thu hoch cy con ................................................................................................. 25
9.3 Cy c (Rhizophora apiculata Bl.) .................................................................................... 26
9.3.1 Thu hi tr mm ..................................................................................................... 26
9.3.2 Cy tr mm vo bu ............................................................................................. 26
9.4 Cc trng (Lumnitzera racemosa Willd.) ............................................................................... 27
9.4.1 Thu hi, bo qun v ch bin ht ging ............................................................... 27
9.4.2 Gieo m ............................................................................................................... 28
9.4.3 Chm sc ................................................................................................................ 28
9.5 D vi (Ceriops tagal (Perr.) C.B. Rob.) ................................................................................ 28
9.5.1 K thut thu hi, bo qun ging ............................................................................ 28
9.5.2 Cy tr mm vo bu ............................................................................................. 29
9.5.3 Chm sc cy m trong vn ............................................................................. 29
10 Cc bin php phng tr su, bnh hi trong vn m ........................................................... 30
10.1 X l t, ht ging trc khi gieo m ................................................................................ 30
10.2 V sinh vn m ................................................................................................................. 31
10.3 Chm sc vn m............................................................................................................. 31
10.4 Cc bin php tr su, bnh hi............................................................................................ 31
Ti liu tham kho .................................................................................................................................... 33
Danh sch bng
Bng 1: Vt liu trng rng ca mt s loi cy rng ngp mn ti Sc Trng. ....................................... 14
Bng 2: S bin i mu sc ca tri khi chn mt s loi cy rng ngp mn. ................................... 15
Bng 3: c im ht ging, k thut gieo v chm sc mt s loi cy rng ngp mn ti vn m. 20
Bng 4: K hoch gieo, chm sc v thu hoch mt s loi cy rng ngp mn. .................................... 21
Danh sch hnh
Hnh 1: Rng ngp mn Vnh Chu vi cc loi c, Bn, Mm pht trin. .........................................7
Hnh 2: Rng ngp mn C Lao Dung v Long Ph vi Bn chua pht trin ch yu. ...........................7
Hnh 3: Vn m cy ngp mn trn t cao phi thng xuyn ti nc............................................9
Hnh 4: Vn m cy ngp mn c xy dng chm, thng xuyn ngp nc thy triu. ..................9
Hnh 5: Vn sn xut cy con trong ti bu. ............................................................................................ 11
Hnh 6: Gin che lung gieo ht v m cy............................................................................................. 11
Hnh 7: Vn m chm thch hp cho a s cy rng ngp mn. .......................................................... 12
Hnh 8: Vn m sn xut cy Bn con r trn. ..................................................................................... 12
Hnh 9: S vn m ni. .................................................................................................................... 13
Hnh 10: Thu hi tr mm cc loi cy h c........................................................................................ 14
Hnh 11: Thu hi tri Mm. ......................................................................................................................... 14
vi
Hnh 12: Ly t chun b ng bu. ......................................................................................................... 17
Hnh 13: Trn t vi tro tru v phn bn trc khi ng bu. ................................................................ 17
Hnh 14: Mn b thc vt c sn trn bi bin. ......................................................................................... 17
Hnh 15: Xp bu vo lung. ...................................................................................................................... 18
Hnh 16: Chun b t gieo cy r trn. ...................................................................................................... 19
Hnh 17: La chn cy Bn thu hi ging. ................................................................................................. 22
Hnh 18: L, hoa v tri Mm bin. ............................................................................................................ 24
Hnh 19: Chm sc cy mm con trong vn m................................................................................... 25
Hnh 20: Tiu chun cy xut vn. .......................................................................................................... 25
Hnh 21: Khng chn tr mm ra nhiu l, r. ...................................................................................... 26
Hnh 22: Cy c tiu chun xut vn. ........................................................................................... 27
Hnh 23: L v hoa ca loi Cc trng (Lumnitzera racemosa). ................................................................ 27
Hnh 24: Rng Cc trng trng thun loi. ................................................................................................ 28
Hnh 25: L v hoa ca cy D vi. ........................................................................................................... 28
Hnh 26: Qu D vi khi chn chun b trng rng. .................................................................................... 29
Hnh 27: Cua, cng o hang lm cht cy con. ....................................................................................... 30
Hnh 28: Cua, cng cn hi cy con trong vn m. .............................................................................. 30
Hnh 29: Su v nm gy hi cy con. ....................................................................................................... 30
Hnh 30: Su non n l c..................................................................................................................... 30
Tc gi nh chp
Tc gi chp tt c cc nh ngoi tr hnh 27 - 30 ca L Ha Khng 2010.
Nhng k hiu, ch vit tt
Atonik 1,8 DD, 5 G Nitrophenolate 0,9%
Benlat 1-(butylcarbamoyl)-2-benzimidazol-methylcarbamat
BMZ B Hp tc Kinh t v Pht trin Lin bang c
Captan Thiophthalimide
DAP Diamon photphate
Formalin HCHO
GTZ T chc Hp tc K thut c
NPK(16:16:8) N2O 16% + P2O5 16% + K2O 8%
No. S
Vipac 88 - Naphthyl Acetic Acid ( - N.A.A) + - Naphthoxy Acetic Acid ( -
N.A.A) + ZnSO4 + MgSO4 + CuSO4 + NPK
7
1 Gii thiu
Rng ngp mn ng vai tr quan trng trong
vic chng sng, gi, chng xi l bo v b
bin, h tr cho qu trnh ln bin. Rng cung
cp dinh dng v duy tr nng sut sinh hc
ca h sinh thi vng ven bin ca sng. Bo
v v pht trin rng ngp mn l c s cho
qu trnh pht trin bn vng vng ven bin.
Rng ngp mn c phn b 3 huyn l
Vnh Chu, Long Ph v C Lao Dung. Mi
huyn c cc c im v a hnh, t ai
khc nhau. V thnh phn thc vt th Long
Ph, C Lao Dung ch yu l Bn chua (Hnh
2); trong khi Vnh Chu s loi cy u
th nhiu hn nh Mm bin, mm en,
c, ng (Hnh 1).
T nm 1990 tr li y, din tch rng ngp
mn vng ven bin tnh Sc Trng khi
phc c khong 3000 ha (FIPI, 2006).
Rng pht huy tc dng gp phn bo v
mi trng, m rng din tch t ai, hn
ch xi l, bo v i sng, tng nng sut
thy sn ven b, ci thin thu nhp v vic
lm cho nhn dn a phng.
Hot ng trng rng gn kt vi hot
ng sn xut cy con, mt s loi cy ngp
mn nh Bn chua, Mm bin, c (D
Xun Phng, 2006) c gieo m ti
a phng, bc u cung cp c mt
phn ngun ging cho trng rng. xy
dng c 2 vn m kh qui m Th
trn Vnh Chu, huyn Vnh Chu v x Trung
Bnh, huyn Long Ph.
Tuy nhin, cc vn v k thut chn cy
ging, k thut gieo m, chm sc cy con
trong vn m, tiu chun cy xut vn
cng cn rt nhiu vn t ra cn gii quyt.
Trong khun kh d n Qun l ngun ti nguyn thin nhin vng ven bin ti tnh Sc Trng
mt trong cc mc tiu c t ra l tng cng cc hot ng trng rng nng cao che ph
rng vng ven bin, trong hot ng cung cp cy ging s lng v cht lng gp phn quan
trng n thnh cng ca cng tc trng rng.
Ti liu Hng dn k thut gieo m cy rng ngp mn cung cp nhng k thut c bn nht
trong cng tc chn cy m, thu hi, ch bin, gieo m, k thut lm vn m, k thut qun l v
chm sc cy con.
Hnh 1: Rng ngp mn Vnh Chu vi cc loi
c, Bn, Mm pht trin.
Hnh 2: Rng ngp mn C Lao Dung v Long Ph
vi Bn chua pht trin ch yu.
8
2 S cn thit phi xy dng cc vn m
nhng iu kin t ai thch hp, cc loi cy rng ngp mn thng c kh nng ti sinh t nhin
rt tt. Tuy nhin, i vi mt s dng lp a khng thch nghi cho ti sinh t nhin ca cy rng ngp
mn, c bit l nhng ni b xi l, b bi lp qu mnh. Mt khc ma ra hoa, to qu v sn xut ht
ging, tri ging khng trng hp vi thi im trng rng.
Chng hn, thi im thch hp trng rng Bn Sc Trng l thi im thng 5 - 7 hng nm. V
trng vo thi im ny s trnh c tnh trng ph sa bi lp cy con t thng 8 - 10, hoc ma gi
chng gy xi l nghim trng vo thng 11 n thng 2 hng nm. Nhng tri Bn chua thng chn
vo thng 9 - 12, tp trung vo thng 10 - 11. Thi im ny khng thch hp cho vic trng rng .
Do , lp vn m l cch tt nht c cy con t tiu chun vo ng thi im thch hp cho
trng rng.
9
3 Cc dng vm m
Vm m cy rng ngp mn c thit lp to cy con v chm sc cy con n khi chng c
tiu chun cho trng rng. C cc dng vn m chnh sau y:
Vn m c nh l vm m c thit lp cho chng trnh trng rng lu di. Vn m c
quy m tp trung v u t ln dn n chi ph v gi thnh cy con cao.
Vn m tm thi c xy dng nhng ni trng rng vi din tch nh, ch s dng phc v
cho cc hot ng trng rng trong mt vi nm.
C hai dng vn m cy ngp mn ch
yu hay s dng, l vn m trn t
cao khng ngp nc (vn m ni), vn
m ngp nc thy triu (vm m
chm).
Vn m ni l vm m c thit lp
trn cc khu t kh, khng ngp nc k c
lc triu cao. Vn m dng ny thng
c thit lp cho chng trnh trng rng
lu di, c thit k v xy dng quy m,
u t ln (Hnh 3).
Vn m chm c xy dng nhng
ni trng rng vi din tch nh, ch s dng
phc v cho cc hot ng trng rng
trong vng vi ba nm tr li (Hnh 4).
Hnh 3: Vn m cy ngp mn trn t cao phi
thng xuyn ti nc.
Hnh 4: Vn m cy ngp mn c xy dng
chm, thng xuyn ngp nc thy triu.
10
4 Chn la lp a xy dng vn m
Chn la ni xy dng vm m l bc u tin khi xy dng vm m, nh hng n t l sng
ca cy con v s thnh bi ca cng tc trng rng. Di y l nhng ch khi thit lp vm m.
a. Khng nn chn nhng v tr sau y
o Xa ngun nc, iu ny gy kh khn cho vic ti nc cho cy con;
o Nhng ni trng, d b ngp nc, hoc nhng ni g cao d b xi mn hoc ra tri;
o Xa thn xm gy kh khn cho chm sc;
o Gn cc bi chn th sc vt, d b sc vt ph hoi; v
o Thiu ngun t v phn to bu.
b. Nn to lp vn m nhng ni sau y
o Gn ngun nc ngt hoc nc l ti cho cy hng ngy;
o Thun li cho vn chuyn cc vt liu nh t lm bu, phn bn, cy con em i trng;
o Thun li cho tiu thot nc, khng gy ng nc, t ti xp, thot nc;
o C ly n a im trng rng ngn; v
o Nn t tng i bng phng.
c. Din tch vn m
o Din tch vm m c th bin ng t 1 - 10 ha, ph thuc vo din tch trng rng v lng
cy con i hi cung cp. Nhn chung din tch vn phi ln sn xut cy m, sn xut
v chm sc cy con, lm lip m cy, ng bu v cc hot ng khc.
o Theo kinh nghim, trng mt ha (ha) rng c vi mt 10.000 cy, vi t l d phng
cy cht l 20%, th cn din tch lip m cy l 350 m2, thm din tch lm vic l 150 m
2. Nh
vy din tch thch hp sn xut cy ging trng 1 ha l 500 m2.
o i vi Mm bin, vn m sn xut cy con trong bu nn c din tch khong 2.000 m2
sn xut 100.000 cy ging mi nm, trong din tch lung gieo m chim khong 65%
phn cn li c s dng cho cc cng trnh ph tr nh: li i li, ni chun b t, ti bu v
hn hp rut bu.
o i vi vn m sn xut cy Bn chua r trn th sn xut 1.000.000 cy ging cn din
tch khong 5.000 m2, trong din tch t lm lip gieo chim khong 70%.
11
5 Thit k vn m
Cc vn m cy ging c thit k thnh cc khu chnh sau (xem trang ba v Hnh 5):
(i) Khu cha vt liu: Khu ny dng cha vt liu nh: t kh, tro tru, phn bn, ha cht,
mn... v cc cng c, thit b.
(ii) Khu chun b t v lm bu: dng cho vic x l v trn vt liu lm rut bu nh: t, tro tru v
ng bu.
(iii) Khu sn xut cy con: Khu ny c din tch ln nht chim khong 60 - 70% din tch vn v
c phn thnh cc lung nh; s ht trc tip i vi sn xut cy r trn hoc to thnh cc
lung xp bu ni lon i vi sn xut cy ti bu.
(iv) H thng ti tiu: Xung quanh vn cn c b bao va i li, vn chuyn vt t va ch
ng ti tiu nc. H thng ti l cc rnh c o dc theo ranh vn m m bo
ti v thot nc.
(v) Gin che: B tr h thng gin che m bo cho c khu gieo ht cng nh khu m cy con. Gin
c lm bng cc cc tre chng mi che, sao cho t mi ti mt t khong 1,5 m
thun tin cho vic chm sc cy con. Cn che nng cho cy con bng tm li nha mu en
hoc bng l da nc. Che ma cho cy m bng cc tm nilon trng c ph ln khung
(Hnh 6).
Khu chun b t
Khu mcy con
Hnh 5: Vn sn xut cy con trong ti bu.
Hnh 6: Gin che lung gieo ht v m cy.
12
15 - 20 cm
1,2 m 30 cm
Li i
Lung m
5.1 Vn m chm
a. Vn m cy ti bu (Hnh 7)
o Lung gieo m c o su xung di mt t nn t 15 - 20 cm.
o Lung c kch thc 1,2 m, di ty thuc vo l t, thng thng 20 - 25 m.
o Gia cc lung cha ng i li 30 cm.
o Cc lung c thng vi nhau v thng ra h thng knh ti tiu nc.
b. Vn m sn xut cy con r trn (Hnh 8)
o t lp vn m cy con r trn sau khi chn la, c cy ba hoc xi nhiu ln. Cc loi
c di c dn sch. Sau vn c phn chia thnh cc l nh v o mng rnh to
thnh cc lip gieo m, vi b rng ca lip l 6 m, di 20 - 50 m (ty theo hnh dng ca tng
khu t).
o Tin hnh p b bao xunh quanh vn m m bo ch ng ti tiu nc. Cc mng
rnh c thng sut vi knh rch bn ngoi m bo cung cp nc ti v tiu ng tht
tt.
Hnh 7: Vn m chm thch hp cho a s cy rng ngp
mn.
Hnh 8: Vn m sn xut cy Bn con r trn.
13
1,2
m
Lung m cy
0.3 - 0.4 m
B bao ng i
Foot
path
5.2 Vn m ni
c thit k tng t nh vn m chm nhng c la chn ni t cao, t ngp nc v khng
cn h thp cao nn lung (Hnh 9).
Hnh 9: S vn m ni.
14
6 La chn loi cy trng rng thch ng vi cc dng lp a
6.1 Thu hi tri ging v tr mm
Ty theo tng loi cy m thu hi cc loi vt
liu khc nhau, i vi cc loi cy h c
th thu hi tr mm, loi cy Mm th thu hi
tri, loi Bn chua th thu hi ht (Hnh 10 v
11 v Bng 1). Nhn chung a s cc loi cy
ngp mn thu hi tri ging vo thng 8 - 10.
Vic thu hi c thc hin bng cch tro
ln cy hi tri chn, hoc thu nht di nn
rng, hoc thu gom tri ging tri theo thy
triu, cc knh rch ca cc khu rng chn
ging.
Bng 1: Vt liu trng rng ca mt s loi cy rng ngp mn ti Sc Trng.
STT Loi cy Vt liu trng Phng thc trng rng
1 Mm bin (Avicennia marina) Tri Trng thun loi hoc hn giao
2 c (Rhizophora apiculata) Tr mm Trng thun loi
3 ng (R. mucronata) Tr mm Trng thun loi
4 D vi (Ceriops tagal) Tr mm Trng thun loi
5 Bn chua (Sonneratia caseolaris) Ht Trng thun loi
6 Cc trng (Lumnitzera racemosa) Ht Trng thun loi hoc hn giao
Hnh 10: Thu hi tr mm cc loi cy h c.
Hnh 11: Thu hi tri Mm.
15
6.2 Nhn bit tri chn
Bng 2: S bin i mu sc ca tri khi chn mt s loi cy rng ngp mn.
STT Loi cy Mu sc
Khi cn xanh Khi chn
1 Mm bin (Avicennia marina) Mu xanh xm Mu vng nht
2 c (Rhizophora apiculata) Mu xanh m Mu xanh xm, mu xanh cnh gin
3 ng (R. mucronata) Mu xanh m Mu xanh xm
4 D vi (Ceriops tagal) Mu xanh Mu xanh xm, mu xanh cnh gin
5 Bn chua (Sonneratia caseolaris) Mu xanh xm Mu xanh thm
6 Cc trng (Lumnitzera racemosa) Mu xanh Mu cnh gin
6.3 La chn loi cy ngp mn trng rng
Theo kt qu nghin cu (Thnh, 2008) vng ven bin ca sng thuc tnh Sc Trng c khong 22 loi
cy rng ngp mn. vng ca sng, ni c s giao thoa gia ngun nc ngt t sng ra bin,
ngp thy triu ln trung bnh trong ngy cc loi cy in hnh vng ny thng gp l Bn chua
(Sonneratia caseolaris) hoc Da nc (Nypa fruticans). ni xa ca sng, mn ca nc thng
cao hn so vi vng ca sng, thng gp cc loi Mm bin (Avicennia marina) hoc Mm en
(Avicennia officinalis). Trn nhng vng t cao, t mn, ch b ngp khi thy triu ln cao trong thng
hoc trong nm xut hin cc loi Cc (Lumnitzera racemosa) hoc tra nht (Hibiscus tiliaceus).
Kt qu trng rng ngp mn tnh Sc Trng t nm 1993 tr li y, cho thy cc loi cy c trng
thnh rng c t l kh cao l Mm bin (Avicennia marina), Bn chua (Sonneratia caseolaris), c i
(Rhizhophora apiculata).
Cn c vo kh nng thch nghi ca cc loi cy rng ngp mn, iu kin lp a, t ai v cc kt qu
trng rng ngp mn tnh Sc Trng trong nhng nm qua, c th chn la nhng loi cy ngp mn
trng rng ch yu sau y:
6.3.1 Bn chua (Sonneratia caseolaris (L.) Engl.)
Cy Bn chua (Sonneratia caseolaris) l loi cy trng thch hp i vi vng bi bi ven bin gn ca
sng cc x thuc huyn C Lao Dung v Huyn Long Ph. t ph sa c dng bn mm n cht.
Ngp bi thy triu trung bnh hng ngy di 1,5 m. Thi gian ngp t 6 n 12 gi trong ngy.
6.3.2 Mm bin (Avicennia marina (Forssk.) Vierh.)
Cy Mm bin (Avicennia marina), l loi cy trng thch hp i vi vng bi bi ven bin xa ca sng
cc x huyn Vnh Chu. t ph sa dng bn mm n cht. Ngp bi thy triu ln trung bnh
hng ngy di 1 m. Thi gian ngp t 6 n 12 gi trong ngy.
6.3.3 c (Rhizophora apiculata Bl.)/ng (Rhizophora mucronata Lamk.)
c i (Rhizhophora apiculata), v ng (Rhirophora mucronata Lume) l nhng loi cy thch hp
cho cc lp a pha sau ai rng Mm v Bn. Nn t c dng bn mm n st mm. Thy triu
ngp 6 - 8 gi trong mt ngy. Nhng ni mt t cao ch yu l t st cng, ch ngp nc khi triu
cng th c th h thp mt t, to iu kin cho thy triu ln xung v bi t ph sa trng rng.
16
6.3.4 Cc vng/Cc trng (Lumnitzera racemosa Willd.)
Cc trng sng vng ven bin c t bn cht n t st cng, vi thch ng rng t vng ngp
triu trung bnh ti vng t ch ngp khi triu cng v chng c th chu ng c nhng vng b
ngp ng trong mt khong thi gian nht nh bi nc ngt, nhng cng sng c trong mi trng
c mn qu cao ln ti 78 (Wells, 1982).
6.3.5 D vi (Ceriops tagal (Perr.) C.B. Rob.)
D vi (Perrottet) C.B. Robinson thch hp cho cc lp a pha sau ai rng Mm v Bn. Nn t c
dng bn mm, bn cht, n rt cht, t tht hoc pha ct. Thy triu ngp t nht l 4 gi trong mt
ngy. Nhng ni mt t cao, nn t cht hoc rt cht, thy triu ch ngp khi ln cao trong ngy th c
th h thp mt t. To cho thy triu ngp ln mt t, v bi t ph sa trng D. So vi c, th
D vi c sinh khi nh hn.
17
7 K thut gieo m cy con ti bu
7.1 Chun b t
Dng lung ni
t c ly t bn ven cc knh rch,
phi kh, p nh (Hnh 12) trn ln vi tro
tru hoc mn b thc vt (sp) (Hnh 13)
theo t l 5:1, c trn thm phn chung v
phn NPK (0,5%) t ng rut bu phi l
t ti, xp, thm nc, ng knh ht t
18
7.4 Xp bu vo lp m cy
Hn hp rut bu c b y ti bu v nn
cht theo ng thao tc k thut. Xp bu
thnh hng vo lung m cy (Hnh 15)
trc khi cy cy con vo bu khong 7 - 10
ngy cho t trong bu n nh v phn
trong bu phn hy, sau bm nc ngp
bu t, ri tho nc ra ngoi. Mi tun
bm ngp bu 1 ln gi m cho bu t.
7.5 Gieo ht, cy cy m, tr mm vo bu
Trc khi gieo ht hoc cy cy m hay tr mm, bu t cn c ti m nc cn thn.
o i vi tr mm cc loi nh c, ng, D vi cm trc tip 1/3 tri vo gia ti bu, gi tr
mm ngay ngn theo hng thng ng. Nn chn nhng ngy tit tri rm mt hoc lc sng
sm v chiu ti cy tr mm.
o i vi Bn chua, Cc trng do t l ny mm thp nn cn gieo 2 n 3 ht trn mt bu.
o Hoc sau khi thu hi v x l, ht c gieo trc tip xung lung gieo cy m c chun b
sn. Sau khi cy m t chiu cao 5 - 7 cm th nh cy vo bu.
o i vi Mm bin tri cng c gieo trc tip vo bu v khi no tri ny mm s c vn
chuyn vo lung m.
7.6 Chm sc cy m trong vn
Lm gin che: Che bng 60 - 70% cho cy con bng tm li nha mu en hoc l da nc trong
thi gian khong 2 tun u; sau 1 thng, ty theo tnh hnh thi tit v tnh trng ca cy m iu chnh
t l che sng khong 30 - 50%. Sau 2 thng gim dn t l che bng xung cn 20 - 30% v sau 3 thng
th d b gin che hon ton khi cy con cng cp.
Ti nc: Khi cy mi cy, mi ngy ti 2 ln vo bui sng v chiu ti, mi ln ch ti 1 lng
nc nh t mt lung. Khi cy ln, nhu cu nc tng ln, cn ly nc thy triu vo ngp
bu.
Bn phn: Phng php bn phn l ha phn vo nc ti cho cy, 1 lt nc ha 3 - 4 gram
phn NPK (16:16:8) + DAP. Sau khi ti phn, phi dng nc l ti ra, khng phn bm nhiu
gy chy l cy. Mi ln bn phn kt hp phun thuc tr su n l.Trong ln bn cui cng ch nn s
dng phn ln v kali lm cho cy cng cp trc khi xut vn v phi ngng hn vic bn phn
hm cy trc khi xut vn 20 ngy.
Nh c, ph vng: Hng tun, kim tra v nh sch c di ngay khi mi mc trn lung m cy hoc
trn ti bu. Lun gi cho mt t thng thong, tng kh nng thm nc, gim s bc hi b mt
bng bin php xi vng thng xuyn.Sau mi trn ma hoc sau 1 s t ti nc cn kim tra v
tin hnh xi vng. Dng que nh hoc mi dao nhn xi nh, su khong 2 - 3 cm, xi xa gc, trnh
lm cho cy con b tn thng.
o bu: Sau 3 thng cn o bu trnh cho cy con m r su xung t.
Hnh 15: Xp bu vo lung.
19
8 K thut sn xut cy con r trn
8.1 Chun b t gieo m
Bc 1: t gieo m c cy ti, ba k v phi i trong thi gian 15 - 20 ngy.
Bc 2: Dn snh c di.
Bc 3: Sau tin hnh bm nc cho ngp mt t 10 - 15 cm ngm trong 3 - 5 ngy.
Bc 4: Bn thm 0,2 m3 tro tru v 10 kg phn NPK (16:16:8) cho 100 m
2 t gieo, dng my xi lm
ti t v tin hnh ba ti bng ri dng chang san phng mt lung.
Tiu c, dit tr mm mng su bnh hi cho t vn m bng ha cht phun, trn u trong t.
Ph bin l dng Formalin phun ln mt lung trc khi gieo ht khong 15 ngy phng tr nm
bnh (1 lt Formalin 38% trong 15 lt nc phun cho 40 m2 mt lung).
8.2 Gieo ht
Ht c gieo theo phng php s t (s
trn nn t m) (Hnh 16), chia lm 3 phn
s lm 3 ln nhm m bo ht c gii
u trn ton din tch lung s. Trc khi s
cn rt ht nc trn mt lung v phi ro 1
ngy. Thi im s ht: ht c s vo lc
sng sm hoc chiu mt lc tri lng gi.
8.3 Chm sc cy con
Ti nc: Ti nc theo phng php bm nc trc tip vo lung gieo, ty theo chiu cao ca
cy con m quyt nh mc cn ti. Vic ti nc phi c thc hin lin tc lun m bo duy
tr m trong vn.
Bn phn: Bn phn vo thi k cy bc vo thng tui 2 n thng tui 5 v chm dt bn phn
trc khi nh cy em trng t nht l 1,5 thng.
t 1: Sau khi s 30 - 35 ngy bn phn t 1 s dng phn Ur vi liu lng 4 - 6 kg/ha.
t 2: Sau khi bn t 1 l 30 ngy vi liu lng 6 - 8 kg/ha.
t 3 v 4: nh k 25 ngy/1 ln vi lng bn 10 kg ur.
t cui bn 15 kg ur + 7 - 9 kg DAP/1 ha/1 ln sau ln 4 l 25 ngy.
Hnh 16: Chun b t gieo cy r trn.
20
9 K thut sn xut mt s loi cy ngp mn
Mi loi cy c c im v ht ging khc nhau, dn n k thut gieo m v chm sc cng khc
nhau. Bng 3 v Bng 4 ch ra mt cch chi tit cho tng loi.
Bng 3: c im ht ging, k thut gieo v chm sc mt s loi cy rng ngp mn ti vn m.
Loi cy
c im ht
Cch
gieo
ht
Chm sc Thu
hi
(thng)
S
ht/
tri
Trng
lng
tri/kg
Vt
liu
gieo
Thi
gian bt
u ny
mm
Mm bin
(Avicennia
marina)
7 - 9 1 300 Tri 3 ngy
Gieo
trn mt
t
Ti nc m
hng ngy + Phng
tr cua, cng
c
(Rhizophora
apiculata)
7 - 10 1 40 Tr
mm 7 ngy
Cm
su 1/3
tri
Ti nc m
hng ngy + Phng
tr cua, cng
ng (R.
mucronata) 7 - 9 1 10 - 12
Tr
mm 7 ngy
Tr
mm
cm su
1/3 tri
Ti nc m
hng ngy + Phng
tr cua, cng
D vi (Ceriops
tagal) 6 - 8 1 120
Tr
mm 10 ngy
Tr
mm
cm su
1/3 tri
Ti nc m
hng ngy + Phng
tr cua, cng
Bn chua
(Sonneratia
caseolaris)
8 - 11 500 -
1.500 10 - 12 Ht 4 ngy
Rc
mnh
trn nn
lung
Ti nc m
hng ngy + Phng
tr cua, cng
Cc trng
(Lumnitzera
racemosa)
8 - 9 1 8.000 -
10.000 Ht 7 ngy
Gieo
trn mt
t
Ti nc m
hng ngy + Phng
tr su bnh hi.
21
Bng 4: K hoch gieo, chm sc v thu hoch mt s loi cy rng ngp mn.
Hot ng Thng
1 2 3 4 5 6 7 8 9 10 11 12
Lp k hoch v kinh ph cho hat
ng trng rng
Thit k trng rng
Bn chua (Sonneratia caseolaris)
-Thu hi tri v gieo ht
-Lp v qun l vn om
-Trng rng
Mm bin (Avicennia marina)
-Thu hi tri v gieo ht
-Lp v qun l vn om
-Trng rng
c (Rhizophora apiculata)
-Thu hi tri v gieo ht
-Lp v qun l vn om
-Trng rng
Cc (Lumnitzera racemosa)
-Thu hi tri v gieo ht
-Lp v qun l vn om
-Trng rng
D (Ceriops tagal)
-Thu hi tri v gieo ht
-Lp v qun l vn om
-Trng rng
Qun l, bo v rng
nh gi chng trnh trng rng
hng nm
22
9.1 Bn chua (Sonneratia caseolaris (L.) Engl.)
9.1.1 Thu hi, bo qun v ch bin ht ging
Thu hi ging
Ngun ging ti Sc Trng nn thu hi cc lm phn rng t nhin, hoc rng trng ti x An Thnh
Nam, huyn C Lao Dung v x Trung Bnh, huyn Long Ph. Bi v hai x ny c rng trng v rng t
nhin sinh trng tt, thch nghi vi iu kin t nhin nh t ai, kh hu, mn ca vng ca sng
ven bin Sc Trng (Hnh 17).
Cn tin hnh vic kho st chn khu rng t yu cu cho ging tt trc khi thu hi. Cc khu rng
trng t cc tiu chun sau y c th dng thu hi ging:
Sc sinh trng ca rng t mc t trung bnh kh tr ln so vi khu vc.
Cy mc tng i ng u, t l sng cao.
Tui rng t 5 nm tr ln, c nhiu cy sai bng sai tri.
v tr tng i thun li cho vic thu hi, vn chuyn ging.
Ngoi vic chn rng, khi thu hi cn phi tin hnh chn nhng cy m tt ly ging, cc cy m
c chn ly ging nn cch xa nhau, ti thiu l 10 - 15 m. Nhng cy t cc yu cu theo trt t
quan trng sau y c th chn lm cy m ly ging:
Sinh trng chiu cao v ng knh thn vt hn nhng cy xung quanh.
Thn thng, khc thn di cnh di v khng hoc rt t khuyt tt.
Hnh 17: La chn cy Bn thu hi ging.
23
B r dy, rng v cn i.
C tri, cng sai cng tt.
Bo qun v ch bin ht ging
Tri ging thu t rng v, em 5 - 7 ngy cho phn hy phn tht qu, sau dng sng i ly ht.
Ht em ra nc l cho sch, ni rm mt cho ro nc, sau em gieo trn lung chun b
sn.
9.1.2 Sn xut cy con trong bu
Thi v gieo ht to cy con
T thng 10 n thng 11. Ht sau khi c ra sch, phi ro nc th tin hnh gieo m. Nn gieo
ht thnh vi t, mi t cch nhau 5 - 7 ngy c th ri u cc cng vic nh cy cy, ti nc,
lm c, ph vng, bn phn v c cy ging xut vn u n trong sut ma trng rng.
Lm lung gieo ht v m cy
Lung gieo ht to cy m: lm trn nn t thp, c lp bn lng 5cm. Ri phn NPK 20 kg/1.000 m2.
Sau dng chang san phng mt lung to thnh dng bn sn st. cho nh sng c phn phi
u trn lung v tin che bng nn b tr lung gieo theo hng ng - Ty. Ngoi ra, nhm phng
bnh l c r hoc thi r, trc khi gieo ht 1 ngy cn x l t lung gieo bng Benlat (6 gram Benlat
ha trong 10 lt nc phun u cho 100 m2) hoc Captan (4 tha Captan ha trong 5 lt nc phun cho
100 m2). Lung m cy trong ti bu: thp 10 cm, lung rng 1 m, di 10 m.
Cy cy m vo bu
Nh cy m: Khi cy m t 20 - 25 ngy tui, c 8 - 10 l, cao 0,5 - 10 cm th nh cy vo bu.
Trc khi nh phi ti m lung gieo. Dng tay nh cy m nh nhng ch c r v t cy vo
khay c nc sch ngp r.
Cy cy: Dng que chc l chnh gia rut bu, chiu su ca l bng chiu di ca r cy. t cy
ngay ngn, dn t lp xung quanh v n nh cho t cht c r. Nn chn nhng ngy tit tri rm mt
hoc lc sng sm v chiu ti cy cy.
Ti nc: Ti nc gi m thng xuyn.
Thu hoch cy con
Sau khong 4 - 5 thng k t khi cy c cy vo ti bu, cy con c th pht trin tiu chun xut
vn em i trng. Cy con cao 80 - 100 cm vi ng knh c r khong 1 cm. C thn thng v b r
tt; tn l xanh ti. Cy khe mnh v khng b su bnh.
9.1.3 Sn xut cy m r trn
Chun b t gieo m
t gieo m c cy ti phi i t 15 - 20 ngy, ba k v san phng, trn tro tru v phn NPK
(16:16:8). Bm nc cho ngp mt t 10 - 15 cm ngm trong 3 ngy mi tin hnh ba ti bng.
Gieo ht
Ht c gieo theo phng php s t (s trn nn t m). Chia ht lm 3 phn s lm 3 ln
nhm m bo ht c gii u trn ton din tch lung s. Trc khi s cn rt ht nc trn mt
24
lung v phi ro 1 ngy. Thi im s ht: ht c s vo lc sng sm hoc chiu mt lc tri lng
gi.
Chm sc cy con
Sau khi s 7 ngy th ht ny mm, sau 10 - 12 ngy sau ra 2 l mm, sau 1 thng c 8 - 10 l.
Ti nc theo phng php bm nc trc tip vo lung gieo, ty theo chiu cao ca cy mm m
quyt nh mc cn ti. Lun m bo duy tr m trong vn. Bn phn vo lc thng tui 2
n thng tui 5 v chm dt bn phn trc khi nh cy em trng t nht l 1,5 thng:
t 1: Sau khi s 30 - 35 ngy bn phn t 1 s dng phn Ur vi liu lng 4 - 6 kg/ha.
t 2: Sau khi bn t 1 l 15 - 20 ngy vi liu lng 6 - 8 kg/ha.
t 3 v 4: nh k 10 - 15 ngy/1 ln vi lng bn 10 kg ur + 500 cc Atonik (phn dng)/1
ha/1 ln bn.
Cc t tip theo bn 15 kg ur + 7 - 9 kg DAP/1 ha/1 ln vi nh k bnh qun 20 ngy/ln.
Thu hoch cy con r trn
Tiu chun cy con khi xut vn:
ng knh c r: > 1,0 cm;
Chiu cao thn cy: 80 - 100 cm;
Tui cy: 6 - 9 thng tui;
Hnh thi: cy h r pht trin tt, sinh trng tt, khng c su bnh.
Phng php thu hoch
Nh ta tuyn chn, t nh ta u tin khi c khong 40% s cy t tiu chun. Sau khi nh 3 ngy
bn hn hp phn DAP + NPK + Vibac 88 cho cy li. Lng phn bn t 30 - 50 kg/ha ty thuc vo
mt cy cn lu li trong vn. Ln nh chn th hai cch sau khong 1 thng ri. S ln nh tuyn
chn khng c vt qu 3 ln. Trc mi ln thu hoch cy ging phi ngng bn phn trong thi gian
ti thiu l 1,5 thng. Nh cy theo phng thng ng t di ln, khi nh cm (nm) 1/3 thn cy
pha di. Cy con sau khi nh phi b li thnh b, mi b 100 cy m bo cho vic bo qun, vn
chuyn v a n im trng rng.
9.2. Mm bin (Avicennia marina (Forssk.) Vierh.)
9.2.1 Thu hi, bo qun v ch bin ht
ging
Mm bin ra hoa vo thng 3 - 5, tri thng
chn vo thng 7 - 9. Thu hi tt nht vo
thng 8 - 10. Tri cn nguyn vn khng b
su, bnh, c trng lng trn 300 tri/kg.
Tri ging thu t mt t rng hoc thu hi
trn cy. Qu khi chn v qu c mu hi
vng hn so vi qu xanh (Hnh 18).
Sau khi thu hi tt nht l em trng ngay.
Trong iu kin cha th trng ngay cn bo
qun bng cch tri ging ni rm mt, ri
lp dy khng qu 20 cm, thng xuyn ti
nc cho tri lun lun m. Thi gian bo
qun khng nn qu 5 - 10 ngy.
Hnh 18: L, hoa v tri Mm bin.
25
9.2.2 Cy cy vo bu
Sau khi thu hi tri ging v, tin hnh cm 2/3 tri xung gia ti bu theo hng thng ng. Nn
chn nhng ngy tit tri rm mt hoc lc sng sm v chiu ti cy (Hnh 19).
9.2.3 Chm sc cy m trong vn
Ti nc: Khi mi cy, mi tun bm ngp lung mt ln. Khi cy ln cao 20 - 25 cm, nhu cu
nc tng ln, cn ly nc thy triu vo ngp bu.
Bn phn: Phng php bn phn l ha phn vo nc ti cho cy, 1 lt nc ha 3 - 4 gram
phn NPK (16:16:8) + DAP. Sau khi ti phn, phi dng nc l ti ra, khng phn bm nhiu
gy chy l cy. Mi ln bn phn kt hp phun thuc tr su n l. Trong ln bn cui cng ch nn s
dng phn ln v kali lm cho cy cng cp trc khi xut vn v phi ngng hn vic bn phn
hm cy trc khi xut vn 20 ngy. Kim sot su bnh hi: Theo di vn m pht hin su
bnh hi, c bin php phng tr kp thi.
9.2.4 Thu hoch cy con
Sau khong 6 - 8 thng k t khi c cy
vo ti bu, cy con c th pht trin tiu
chun xut vn em i trng. Tiu chun c
th ca cy con nh sau:
Cao 30 - 40 cm;
L c t 8 - 10 l (Hnh 20);
C thn thng v b r tt; v
Cy khe mnh v khng b su
bnh.
Hnh 19: Chm sc cy mm con trong vn m.
Hnh 20: Tiu chun cy xut vn.
35 - 40 cm
26
9.3 Cy c (Rhizophora apiculata Bl.)
9.3.1 Thu hi tr mm
Thu hi ging ti cc lm phn rng trng ti x ti Vnh Hi, huyn Vnh Chu. c ra hoa vo thng 3
n thng 5, tri thng chn vo thng 7 - 12, tuy nhin, vic thu hi tri ch nn tin hnh vo thng
8 - 9, lc ny tri chn r, t b su c tri, t l sng cao.
Tiu chun tr mm
Tri cn nguyn vn khng b su, bnh, c
chiu di ln hn 23 cm, ng knh trn 1
cm v c trng lng trn 20 gram, cha ra l
v r (Hnh 21).
Bo qun tr mm
Tri ging thu t rng v, tt nht l em
trng ngay. Nu cha trng ngay cn bo
qun nh sau:
tri ging ni rm mt, ri mt lp
thnh lp dy khng qu 20 cm.
Thng xuyn ti nc cho tri lun lun m.
Thi gian bo qun khng nn qu 10 ngy.
Cho tri ging vo cc bao ti sau t xung knh, rch ni c nc thy triu ln xung thng
xuyn. Bo qun theo cch ny c th ko di khong 15 ngy. Khi vn chuyn tri ging i xa, cn ch
ti m thng xuyn
9.3.2 Cy tr mm vo bu
Cm 1/3 tri c cm trc tip vo gia ti bu, gi tr mm ngay ngn theo hng thng ng. Nn
chn nhng ngy tit tri rm mt hoc lc sng sm v chiu ti cy tr mm.
9.3.3 Chm sc cy m trong vn
Lm gin che
Che bng cy con bng tm li nha mu en trong thi gian khong 1 - 2 tun u; ty theo tnh hnh
thi tit v tnh trng ca cy m iu chnh t l che sng khong 30 - 50%. Sau gim dn cng
v t l che bng khi cy con bt u n nh.
Ti nc
Nhm cung cp nc cho nhu cu sinh trng v pht trin ca cy con. Khi tr mm mi cy, mi
tun bm ngp lung mt ln. Khi cy ln, nhu cu nc tng ln, cn ly nc thy triu vo ngp
bu.
Bn phn
Phng php bn phn l ha phn vo nc ti cho cy, 1 lt nc ha 3 - 4 gram phn NPK
(16:16:8) + DAP. Sau khi ti phn, phi dng nc l ti ra, khng phn bm nhiu gy chy
l cy. Mi ln bn phn kt hp phun thuc tr su n l. Trong ln bn cui cng ch nn s dng
Hnh 21: Khng chn tr mm ra nhiu l, r.
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phn ln v kali lm cho cy cng cp trc khi xut vn v phi ngng hn vic bn phn hm
cy trc khi xut vn 20 ngy.
Nh c, ph vng, lun gi cho mt t thng thong, tng kh nng thm nc, gim s bc hi b
mt bng bin php xi vng thng xuyn. Sau mi trn ma hoc sau 1 s t ti nc cn kim tra
v tin hnh xi vng. Dng que nh hoc mi dao nhn xi nh, su khong 2 - 3 cm, xi xa gc,
trnh lm cho cy con b tn thng.
Tiu chun cy xut vn
Sau khong 4 - 5 thng k t khi c cy vo ti bu,
cy con c th pht trin tiu chun xut vn em
i trng. Tiu chun c th ca cy con nh sau:
Cao 40 - 50 cm, c t 8 - 10 l (Hnh 22).
C thn thng v b r tt, cy khe mnh v khng
b su bnh.
9.4 Cc trng (Lumnitzera racemosa Willd.)
9.4.1 Thu hi, bo qun v ch bin ht ging
Chn cy m
Cy m c tui t 10 - 15 nm, sinh trng
v pht trin tt, khng su bnh, khng
khuyt tt, tn cn i. Tt nht l thu ging
lm phn rng t nhin thun loi hoc rng
trng c cht lng tt.
K thut thu hi, bo qun
Tri Cc trng chn vo thng 8 - 10, nhng
thi gian thu ht ging tt nht vo thng 9 khi
tri cn ang nm trn cy. Tri ging sau khi
thu hi c phi ly ht, sau phi kh
v ct tr ni thong mt.
Hnh 22: Cy c tiu chun xut vn.
Hnh 23: L v hoa ca loi Cc trng (Lumnitzera
racemosa).
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9.4.2 Gieo m
Cch 1: To cy con trong vn m theo phng php ngm ht bng nc l trong vng 24 gi, vt
ht v gieo trong khay ny mm, khi nt nanh th cy trc tip vo bu
Cch 2: Gieo vi ht trc tip trn cc lung
9.4.3 Chm sc
Chm sc cy con cn ch trng n ch
nc ti thng xuyn, ni vn m thit
k chm c th a nc thu triu ln xung
hng ngy. Sau thi gian chm sc khong 8
n 10 thng, chiu cao cy t t 30 - 40 cm
l lc xut vn. Hnh 23 v 24 cho thy hoa
v hnh thc tng trng ca rng cc trng.
9.5 D vi (Ceriops tagal (Perr.) C.B. Rob.)
D vi thch hp vng c t bn cht vng ca sng, ven bin, thng xuyn c thy triu ln
xung, vng t giu cht hu c, thnh phn c gii t ch yu l st, mn.
Bin thch ng rng t vng thp ti vng t cao. Tuy nhin, ngp triu thch hp cho s sinh
trng ca D vi t 100 - 200 ngy/nm. ngp triu cao, hoc thp di 100 ngy/nm v trn
200 ngy/nm l t thch hp cho s sinh trng ca D vi .
Chng thch hp mn t 20 - 30o/oo ti C Mau v c kh nng chu mn n 60 - 80
o/oo ti Bc
Liu v Cn Gi, thnh ph H Ch Minh. Hnh 25 cho thy hoa ca cy D vi.
9.5.1 K thut thu hi, bo qun ging
Tri D vi (Hnh 26) chn vo thng 8 - 10,
khi chn tri chuyn sang mu xm nu, thi
gian thu vt tri ging tt nht vo thng 9.
Khi thu hi xong c gng em trng ngay.
Nu cha trng c ngay, phi tri ging
ngm di ni nc chy, c bng mt.
ni kh phi thng xuyn ti nc ngy 2
ln v khng nn gi lu qu 15 ngy.
Hnh 24: Rng Cc trng trng thun loi.
Hnh 25: L v hoa ca cy D vi.
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Tiu chun tri ging
Tri ging phi cn nguyn vn, cha
m r,
Tri di 15 - 25 cm,
ng knh tri 0,5 - 1,0 cm, v
Trng lng bnh qun 80 - 120 tri/kg.
9.5.2 Cy tr mm vo bu
Cm 1/3 tri D vi cm trc tip vo gia ti bu, gi tr mm ngay ngn theo hng thng ng.
9.5.3 Chm sc cy m trong vn
K thut chm sc cy D vi c thc hin nh i vi c.
Tiu chun cy xut vn:
Sau khong 4 - 5 thng k t khi c cy vo ti bu, cy con c th pht trin tiu chun
xut vn em i trng. Tiu chun c th ca cy con nh sau.
Cao 30 - 35 cm, c t 6 - 8 l.
C thn thng v b r tt, cy khe mnh v khng b su bnh.
Hnh 26: Qu D vi khi chn chun b trng rng.
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10 Cc bin php phng tr su, bnh hi trong vn m
Giai on cy con trong vn m rt mn cm vi cc tc ng ca thi tit, kh hu v su, bnh. Do
vy, kim sot su, bnh hi l vic lm rt cn thit, duy tr v bo m s sinh trng bnh thng
ca cy con trong sut thi gian vn m.
Sau y, l mt s ri do chnh do su, bnh gy ra trong vn m cn lu :
10.1 X l t, ht ging trc khi gieo m
Phi i t, phi t trong khong 10 ngy vi nhit ngoi tri khong 30 - 35C. Bin php
ny tuy i hi thi gian lu v tn cng nhng c th p dng c vi quy m ln (xem
chng 8.1).
Khi cn gp t gieo m kp thi c th dng cc loi ha cht phun, trn u trong t. Ph
bin l dng Formalin phun ln mt lung trc khi gieo ht khong 15 ngy phng tr
nm bnh (4 lt Formalin 38% trong 60 lt nc phun cho 150 m2 mt lung).
Hnh 27: Cua, cng o hang lm cht cy con. Hnh 28: Cua, cng cn hi cy con trong vn
m.
Hnh 29: Su v nm gy hi cy con. Hnh 30: Su non n l c.
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Trc khi gieo, ngoi vic kch thch cho ht ging ny mm, cn tin hnh tiu tr mm mng
su bnh cho ht:
o Loi b ht cc tp vt trong l ht.
o Bo qun ht khng b tip xc vi mi trng su bnh hi.
o Ngm, trn ht vo cc dung dch sau: dung dch Formalin 0,15% trong 15 - 30 pht, hay
dung dch Sunfat ng 0,3 - 0,5% trong khong 2 gi, hay thuc tm 0,5% trong 2 gi.
10.2 V sinh vn m
Hn ch ti a vic s dng ngun nc nhim, nc c ti cho vn m. Thay nc
cho vn m cy r trn trong thi gian ngp nc.
X l cc cy con b cht, gom li v a ra khi vn m ri t.
Thng xuyn pht quang bi rm, c di xung quanh vn. Ri vi bt xung quanh b bao v
cc li i li.
Gi cho vn m lun thong, khng nc bn ng trong vn.
V sinh cc dng c v vt liu trong vn.
10.3 Chm sc vn m
Ht ging thu hi phi c kim tra su, bnh trc khi em gieo. Cn kim tra theo di vn m
thng xuyn nm bt sm s xut hin cc loi su bnh hi, c bit lc ht hoc tr mm mi
m chi, giai on ny l giai on mn cm nht, nn thng b su, bnh ph hoi.
Cng trong giai on m chi, cc loi cua cng thng cn ph cy non (Hnh 27 v 28). Cn chuyn
nhng cy b su bnh ra xa khu vc vn m trnh s ly lan trong vn m.
Mt s bin php chm sc sau y nu thc hin khng ng k thut s to iu kin cho su bnh
xm nhp v pht trin, cn phi hn ch:
Phun thuc: qu liu lng gy chy l.
Bn phn: qu nhiu gy lp l.
Ti nc: qu m gy ng nc (i vi phng thc gieo m trong bu t trn lung
m nn cng).
Ngoi ra, vic tng cng kim tra theo di vn m nm bt sm s xut hin cc loi su bnh
hi c x l thch hp cng l bin php phng nga c hiu qu tch cc.
10.4 Cc bin php tr su, bnh hi
Su n l
Bin php canh tc: Khi su ha nhng cho nc vo lip ngp gc cy nhng b cht. y l
bin php c hiu qu cao phng tr s ph hoi ca su hi v an ton cho mi trng. Sau
cn lm v sinh sch s xung quanh khu vc sn xut cy.
Bin php ha hc: Su giai on tui 1 - 2, c th s dng 1 s loi thuc tip xc nh: Viher 25
ND, pha 0,5 lt/400 lt nc phun cho 1 ha hoc Decis 25 EC, pha 10 CC/bnh 8 lt, phun 50
bnh/ha.
Khi su tui 3 - 4, c th s dng thuc v c: Dazinon 50%, pha 1 lt/400 lt nc phun
cho 1 ha. Cng c th s dng cc loi thuc BVTV nh: Bundock, Pardan, Regent dit tr.
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Su c chi
Bin php canh tc: khi thy c trng su xut hin ri rc trn cc phin l, phi ngt phn l
c trng b xa ra khi vn, su non n ra khng th di chuyn i xa c s b cht.
Bin php ha hc: Khi pht hin thy su non c kh nng pht trin thnh dch c th dng
thuc: Padan 10 G vi liu lng 0,6 - 0,8 kg/ha. Padan c th hn hp vi nhiu loi thuc tr
su khc nh: Padan 10 G 380 hot cht + Azodrin 375 hot cht; hay Padan 380 hot cht +
Parathion + 280 hot cht.
Pha hn hp trong 400 lt nc phun cho 1 ha.
Nm c r
y l loi bnh c kh nng gy hi rt nghim trng do c th gy cht cy con hng lot v ly lan
nhanh trn din rng. Nguyn nhn gy bnh l do Nm Rhizoctonia gy nn.
Triu chng: thng xut hin trong vm m to cy con trong bu ch yu giai on cy di 1,5
thng tui v vn m cy con r trn ch yu thng tui 2 - 4. Vt en xut hin gn c r to thnh
vt ngang quanh thn, sau lan truyn rt nhanh kt thnh mng nh kiu mng nhn l lng phn
gia thn cy lm cho cy b ho v cht hng lot. Bnh pht trin nghim trng nu vn m iu
kin m t lin tc.
Bin php phng tr:
Bin php canh tc
o Trc khi gieo ht cn dn vn m sch s, thu gom c em t, t gieo m phi
c lm ti xp, thot nc tt.
o C th x l t trc khi gieo ht bng cch sy t nhit 60C trong thi gian 30 pht
hoc phi i t trong khong 10 ngy nhit 30C.
o Thng xuyn theo di, pht hin kp thi, khi c du hiu bnh xut hin, phi m bo
khng mt lung gieo b m t, nc bn trng ng.
Bin php ha hc
o S dng thuc dit nm nh: Kitazin v Roval x l t.
o Khi bnh mi pht sinh, c th dit tr bng cc loi thuc sau y: Vicben - C 50 BHN nng
20 gram/bnh 8 lt; hay Vicben - C 50 BHN nng 15 gram + Fuji-One40ND 20 ml/bnh 8
lt, hay Tobsim v Tilt 250 ND trn ln em phun vi liu lng 24 ml/bnh 8 lt.
Ngoi nhng loi su bnh thng gp trn y, trong vn m cn gp mt s bnh hi khc nh
bnh hoi t, bnh m nu... nhng thng xut hin ri rc v khng gy hi nghim trng.
Ring i vi cy con r trn, do thi gian nui dng trong vn kh di v ch canh tc khng cao
do vy nhng thi im mn cm nh: thi tit giao ma ma nng hoc sau khi bn phn 2 - 3 ngy
cn ch ng phun thuc phng tr dch su n l. Cc loi thuc thng dng nh: Decis, Regent, Cyper
Alpha, Padan, Bulldock c s dng vi nh k khong 10 - 15 ngy/ln s hn ch ti a kh nng
gy dch.
Cn lu rng vic p dng h thng k thut gieo m, v sinh vn thng xuyn, sm pht hin s
xut hin cc loi su bnh v chut ph hoi dit kp thi l ni dung quan trng v hiu qu nht
trong vic phng tr cc tn hi do cc tc nhn ny gy ra.
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Ti liu tham kho
Xun Phng, 2006. Nghin cu trng th nghim c i (Rhizophora apiculata) trong ti bu
nylon ti vng bi bn kh khn huyn Vnh Chu, tnh Sc Trng. Phn vin nghin cu
khoa hc Lm nghip Nam B, Tp HCM. 40 trang.
Phn vin iu tra quy hoch rng Nam B (FIPI), 2006. Bo co hin trng s dng t vng phng h
xung yu tnh Sc Trng. 16 trang.
Phm Trng Thnh, 2008. Rng ngp mn Sc Trng 1965 -2008. Ti liu d tho cha xut bn.
Wells, A. G. 1982. Mangrove vegetation of Northern Australia. In. Clough, B.F. (ed.) Mangrove
ecosystems in Australia: structure function and management. Australian National University
Press, Canberra.
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