PAUL TRNG, TRN TN VN V ELISE PINNERS

HNG DN K THUT

Trng c Vetiver gim nh thin tai, bo v mi trng

INTERNATIONAL BNG C VETIVER: Gii php tin cy, hiu qu, thn thin vi mi trng

NH XUT BN NNG NGHIP H NI - 2008

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MC LCLI GII THIU LI NI U LI CM N V CC TC GI 11 13 15 Error! Bookmark not defined. 17 17 17 17 18 18 18 19 20 20 25 25 25 26 26 26 26 27 27 27 27 27 28 28 28 28 28 28

Phn 1. CY C VETIVER 1. GII THIU 2. MT S C IM CHNH CA C VETIVER 2.1. c im hnh thi 2.2. c im sinh l 2.3. c im sinh thi 2.5. c im di truyn 2.5.1. Ging Vetiveria zizanioides L (tn mi: Chrysopogon zizanioides L) 2.5.2. Ging Vetiveria nemoralis 2.6. Kh nng tr thnh c di Phn 2. NHN GING C VETIVER 1. GII THIU 2. VN M 3. NHN GING 3.1. Tch khm trng r trn 3.2. Nhn ging t cc b phn ca cy m 3.2.1. ChuNn b ging 3.2.2. Phun dung dch bo ty 10% 3.2.3. X l v trng 3.2.4. u im v nhc im ca phng php trng bng r trn v hom 3.3. Trng bng chi hoc nui cy chi trong ng nghim 3.4. N ui cy m t mt phn ca cy m 4. CHUN BN TRN G 4.1. Ti bu 4.2. Bng c 4.2.1. u im ca vic s dng ti bu v bng c 4.2.2. N hc im ca vic s dng ti bu v bng c 5. VN M C VETIVER VIT N AM

Phn 3. TRNG C VETIVER GIM NH THIN TAI, BO V C S H TNG 35 1. MT S DN G THIN TAI C TH GIM N H BN G C VETIVER 35 2. MT S N GUYN L N NN H MI DC 36 2.1. Hnh thi mi dc 36

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2.2. S n nh ca mi dc 36 2.2.1. Cc sn dc t nhin, taluy ng v.v. 36 2.2.2. Xi l b sng, b bin v mt n nh cc cng trnh gi nc 36 2.2.3. Lc gy trt 37 2.2.4. Lc khng trt 37 2.3. Cc kiu mt n nh mi dc 38 2.4. Tc ng nhn sinh n trt l 38 2.5. Gim nh trt l 38 2.5.1. Xc nh cc khu vc c nguy c trt l 38 2.5.2. Phng nga trt l 38 2.5.3. X l, khc phc hu qu trt l 39 2.6. n nh mi dc bng thc vt 40 2.6.1. Mt s u nhc im ca bin php bo v mi dc bng thc vt 40 2.6.2. n nh mi dc bng thc vt Vit N am 41 3. N NN H MI DC BN G C VETIVER 42 3.1. N hng c im c o ca c Vetiver thch hp vi mc ch n nh mi dc 42 3.2. N hng c im c o ca c Vetiver thch hp vi mc ch gim nh thy tai 43 3.3. Sc khng ct v khng ko ca r c Vetiver 44 3.4. c tnh thy lc 45 3.5. p lc nc l rng 45 3.6. Mt s ng dng ch yu ca bng c Vetiver gim nh thin tai, bo v c s h tng 46 3.7. Mt s u nhc im ca bng c Vetiver 46 3.7.1. u im 46 3.7.2. N hc im 47 3.7.3. Phi hp vi cc bin php khc 47 3.8. Phn mm m hnh ha v thit k bng c Vetiver 48 4. HN G DN CHI TIT N NN H MI DC BN G C VETIVER 48 4.1. Mt s lu 48 4.1.1. Mt s lu v k thut 49 4.1.2. Mt s lu khc khi ra quyt nh, lp k hoch v t chc trng c Vetiver 49 4.2. Thi gian trng c Vetiver 49 4.3. Vn m c Vetiver 50 4.4. ChuN n b trng c Vetiver 50 4.5. Thit k trng c Vetiver 50 4.5.1. sn dc t nhin, taluy, b ng t p 50 4.5.2. ni xi l b sng, b bin v cc cng trnh gi nc mt n nh 51 4.6. Trng c Vetiver 51 4.7. Chm sc c Vetiver 52 4.7.1. Ti nc 52 4.7.2. Trng gim 52 4.7.3. Phng tr c di 52 4.7.4. Bn phn 52 4.7.5. Ct ta 52

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4.7.6. Bo v 52 5. MT S D N TRN G C VETIVER GIM N H THIN TAI, BO V C S H TN G VIT N AM 53 5.1. Bo v cc cn ct ven bin Min Trung 53 5.2. Bo v , k, gim nh xi l b sng 54 5.2.1. Bo v , k, gim nh xi l b sng Min Trung 54 5.2.2. Bo v , k, gim nh xi l b sng v bo v cc cm dn c vt l ng bng Sng Cu Long 54 5.3. Bo v k, gim nh xi l b bin 55 5.4. Bo v taluy ng, gim nh trt l ng giao thng 55 Phn 4 TRNG C VETIVER X L NHIM T, NC V BO V MI TRNG 58 1. GII THIU 67 2. N HN G C IM C O CA C VETIVER THCH HP VI MC CH BO V MI TRN G 67 2.1. c im hnh thi 67 2.2. c im sinh l 68 3. PHN G N GA V X L N HIM N GUN N C 68 3.1. Tiu gim nc thi 68 3.1.1. X l cht thi v sinh 68 3.1.2. X l nc thi thm r t bi rc 69 3.1.3. X l nc thi cng nghip 69 3.2. Ci thin cht lng nc thi 69 3.2.1. Chn gi bn t v cc ha cht nng nghip b ra tri t ng rung 69 3.2.2. Hp th v thch nghi vi kim loi nng v cc cht nhim khc 69 3.2.3. Vng t ngp nc 70 3.2.4. Phn mm x l nc thi cng nghip bng c Vetiver 71 3.2.5. Phn mm x l nc thi sinh hot bng c Vetiver 71 3.2.6. Xu th pht trin trong tng lai 72 4. X L N HIM T 72 72 4.1. Kh nng thch nghi vi cc iu kin t xu 4.1.1. Chu c t chua, phn v hm lng Mangan cao 72 4.1.2. Chu c t mn c hm lng N atri cao 72 4.1.3. Phn b kim loi nng trong c Vetiver 72 4.1.4. Kh nng thch nghi vi kim loi nng 73 4.2. Ci to v phc hi t m bng bin php thc vt 73 Phn 5 HN CH RA TRI, XI MN TRONG CANH TC NNG NGHIP V NHNG NG DNG KHC CA C VETIVER 80 1. GII THIU 80 2. HN CH RA TRI, XI MN TRON G CAN H TC N N G N GHIP BN VN G 80 2.1. N guyn l gi t v nc 80 2.2. N hng c im quan trng nht c Vetiver c th gi t v nc 80

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2.3. So snh cc bin php lm rung bc thang v trng c Vetiver theo ng ng mc 81 2.4. Trng c Vetiver vng ng bng hay b l lt 82 2.5. Trng c Vetiver trn vng i ni 83 Hiu qu gi t 84 2.6. Thit k v khuyn nng 84 3. MT S N G DN G KHC TRON G CAN H TC N N G N GHIP 86 3.1. Phng tr su c thn cho la v ng 86 3.2. Lm thc n cho gia sc 86 87 3.3. Lm lp ph nga c di v gi N m cho t 4. CI TO T CAN H TC V BO V CC KHU DN C VT L 87 4.1. Bo v cc n ct 88 4.2. Trng c Vetiver ci thin nng sut vt nui cy trng trong mi trng bt thun i bn kh N am Trung B 88 4.3. Hn ch xi mn, ra tri trn t chua phn nng 89 4.4. Bo v c s h tng nng thn 89 5. MT S N G DN G KHC 90 5.1. Lm th cng m ngh 90 5.2. Lp nh 90 5.3. Lm gch 90 5.4. Lm dy lt 90 5.5. Lm cy cnh 90 5.6. Chit xut tinh du lm m phN m, dc phN m 90 TI LIU THAM KHO 92

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DANH MC BIU BNGBng 1.1. Kh nng thch nghi ca c Vetiver mt s nc Bng 3.1. Cc kiu mt n nh mi dc Bng 3.2. Mt s tc ng vt l ca lp ph thc vt n mi dc Bng 3.3. dc v kh nng to lp ph thc vt trn mi dc. Bng 3.4. Sc khng ko ca r mt s loi thc vt Bng 3.5. ng knh v sc khng ko ca r mt s ging c Bng 3.6. su ra r c Vetiver trn taluy ng Hn B (Khnh Ha) Bng 4.1. Cht lng nc m ly trc v sau khi x l bng c Vetiver Bng 4.2. So snh ngng chu kim loi nng c Vetiver v cc cy c khc 19 38 41 41 44 45 56 71 73

Bng 5.1. Hiu qu ca bng c Vetiver gim nh nc mt chy trn v xi mn, ra tri t nng nghip. 84 Bng 5.2. Gi tr dinh dng ca c Vetiver, c mt v c Kikuyu Bng 5.3. Tnh hnh sn xut v s dng tinh du Vetiver trn th gii 86 91

DANH MC NH V HNH VHnh 1.1. C mc thng ng, rt cao v cng, to thnh hng ro ngn cn ra tri t. Error! Bookmark not defined. Hnh 1.2. C Vetiver chu chy rt tt, ch hai thng sau, khi c ma phc hi tr li. Error! Bookmark not defined. Hnh 1.3. C Vetiver trng trn ct ven bin Qung Bnh (tri) v t chua phn G Cng (phi) Error! Bookmark not defined. Hnh 1.4. C Vetiver trn t chua phn nng Tn An (tri) v t kim nng vng kh nng N inh Thun (phi) Error! Bookmark not defined.

Hnh 1.5. nh hng ca nhit t ti kh nng pht trin r c Vetiver.Error! Bookmark not defined

Hnh 1.6. L c Vetiver: Vetiveria zizanioides (tri) v V. nemoralis (phi).Error! Bookmark not defined

Hnh 1.7. Cy c Vetiveria nemoralis (tri) v Vetiveria zizanioides (phi).Error! Bookmark not defined Hnh 1.9. R c Vetiver trong t (tri v gia) v trong nc (phi).Error! Bookmark not defined. Hnh 1.11. Vetiveria nigritana Mali, Ty Phi. Hnh 2.2. Tch khm c Vetiver Error! Bookmark not defined. Error! Bookmark not defined. 6

Hnh 1.8. R c Vetiver: Vetiveria nemoralis (di) v V. zizanioides (trn).Error! Bookmark not define

Hnh 1.10. Tri: Vetiveria nemoralis (c ) Qung N gi; phi: Ty N guyn.Error! Bookmark not defi Hnh 2.1. Trng c Vetiver bng my (tri) v thu hoch bng tay (phi).Error! Bookmark not defined.

Hnh 2.3. Tch khm (tri), nhng bn hoc phn chung chuN n b trng (phi)Error! Bookmark not def Hnh 2.4. Dnh c Vetiver non (tri) v gi (phi) sn sng mang trng.Error! Bookmark not defined. Hnh 2.5. C r hoc gc (tri) v hom c Vetiver (phi) sn sng mang trng.Error! Bookmark not defi Hnh 2.6. Phun dung dch bo ty (10%) cho c Vetiver ging.Error! Bookmark not defined. Hnh 2.7. Ph kn hom ging bng ti nilon trong 24 gi.Error! Bookmark not defined. Hnh 2.8. Trng trn lung c bn phn chung. Error! Bookmark not defined.

Hnh 2.9. R trn v ti bu (tri), cho c vo ti bu (gia) v sn sng mang trng (phi).Error! Bookmark n Hnh 2.10. Trng c trong cc bng (tri), ly ra (gia) v sn sng mang trng (phi). Error! Bookmark not defined. Hnh 2.12. Vn m Qung N gi (tri) v Bnh Phc (phi).Error! Bookmark not defined. Hnh 2.14. Vn m Bc N inh (tri) v Bc Giang (phi).Error! Bookmark not defined. Hnh 3.1. To thnh bc tng chn sinh hc dy v hiu qu.Error! Bookmark not defined. Hnh 3.2. Minh ha nguyn l n nh mi dc bng c Vetiver (b r cc hng c c tc dng nh nhng neo t (tri). Trong thc t cc hng c Vetiver gip bc tng t ny khi b nc l qut i (phi).Error! Bookmark not defined. Hnh 3.3. Tng quan sc khng ko - ng knh r c Vetiver.Error! Bookmark not defined. Hnh 3.5. M hnh thy lc gim nh cng l bng cc hng cError! Bookmark not defined.

Hnh 2.11. Vn m i hc Cn Th (tri) v Tn Chu (An Giang) (phi).Error! Bookmark not de

Hnh 2.13. Vn m Qung Bnh (tri) v dc ng H Ch Minh (phi).Error! Bookmark not defin

Hnh 3.4. Tc dng tng sc khng ct ca r c Vetiver theo chiu su t.Error! Bookmark not define

Hnh 3.6. Ct chy L Thy (Qung Bnh) nm 1999, lm tr mng ca mt trm bm (tri) v ph sp ngi nh gch ba gian ca ngi ph n ny (phi).Error! Bookmark not Hnh 3.7. a im trng c th nghim (tri); u thng 4/2002 - mt thng sau khi trng (phi) Error! Bookmark not defined. Hnh 3.8. u thng 7/2002 - bn thng sau khi trng - cc hng c mc tt v pht huy tc dng. Error! Bookmark not defined. Hnh 3.9. Thng 11/2002 - cn ct n nh sau ma ma. Lu cy c bn a mc ln rt tt gia cc hng c . Error! Bookmark not defined. Hnh 3.10. Vn m (tri); Trng i tr thng 11/2002 (phi).Error! Bookmark not defined. Hnh 3.11. Bo v m cu dc quc l 1 (tri); Cc loi cy bn a thay th - Thng 12/2004 (phi). Error! Bookmark not defined.

Hnh 3.12. Tham quan thc a sau hi tho thng 2/2003. C Vetiver vn xanh tt d va tri qua ma ng lnh nht trong vng 10 nm (tri); N gi dn Qung Tr tham quan vn m ti nh Qung Bnh thng 6/2003 (phi).Error! Bookmark n Hnh 3.13. Trng c Vetiver cnh m tm, ct ngang mng thot l ra sng Vnh in - Thng 3/2002 (tri); Kt hp cng k bo v b sng Vnh in Thng 11/2002 (phi). Error! Bookmark not defined.

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Hnh 3.14. Thng 12/2004 - cu T Cu - 2 ma l c Vetiver cng vi k bo v tt b sng (tri); N gi dn a phng t trng c Vetiver bo v cc m nui tm (phi). Error! Bookmark not defined. Hnh 3.15. C Vetiver cng k bo v b sng Hng Hu.Error! Bookmark not defined. Hnh 3.16. C Vetiver bo v sng Tr Bng (tri); c hai mi ca mt on Error! Bookmark not defined. ngn mn h lu sng Tr Bng (phi). Hnh 3.17. Bo v mi trong mt on ngn mn (tri) v mt on knh thy li (phi). Error! Bookmark not defined.

Hnh 3.18. Mt on b sng Tr Khc x Bnh Thi b xi l nghim trng (tri); Trc y ngi dn vn dng cc bao ct tm bo v b (phi).Error! Bookmark not defin

Hnh 3.19. N ay c Vetiver c gii thiu v ngi dn nhit tnh tham gia trng (tri); B sng c bo v ngay c trong ma l thng 11/2005 (phi).Error! Bookmark not d Hnh 3.20. C Vetiver bo v sng (tri) v b sng, b knh (phi) An Giang.Error! Bookmark no Hnh 3.21. C Vetiver bo v b cc khu dn c trnh l (tri); N h c Vetiver m mt di b t kh ro rng ti 5m c bo v (phi).Error! Bookmark not defined. Hnh 3.22. C Vetiver trn t chua phn h thng bin G Cng, pha sau rng c (tri), gip gim nh xi l mi v to iu kin cho cy c bn a phc hi (phi). Error! Bookmark not defined. Hnh 3.23. Th nghim c Vetiver bo v mi ngoi h thng bin mi p Hi Hu (tri); N hng c Vetiver c trng bo v mi trong bin t trc 1-2 nm (phi). Error! Bookmark not defined. Hnh 3.24. C Vetiver trng bo v taluy ng dc tuyn ng H Ch Minh, c lp hoc kt hp vi cc bin php truyn thng khc.Error! Bookmark not defined. Hnh 3.25. t thi ra ba bi khi lm ng c th b cun tri theo sng sui (tri) v di chuyn rt nhanh xung h lu nu khng c c Vetiver bo v (phi). Error! Bookmark not defined. Hnh 3.26. Taluy ng lin tc trt l, n t xung gy tc ng (tri) nhng c Vetiver gp phn lm chm li v gim ng k quy m trt l (phi). Error! Bookmark not defined. Hnh 3.27. Ch sau vi trn ma, taluy mi m b xi mn, ra tri nghim trng (tri) v c Vetiver c trng bo v (phi). Sau 8 thng c mc tt, n nh c taluy, ngn chn hon ton xi mn, ra tri.Error! Bookmark not defined. Hnh 4.1. B r v thn l cc k n tng ca c Vetiver, to thnh hng ro chn rt tt. Error! Bookmark not defined. Hnh 4.3. Kh nng hp th v chu c nng N v P cao.Error! Bookmark not defined. Hnh 4.4. C Vetiver loi sch to xanh trong 4 ngy. Error! Bookmark not defined.

Hnh 4.2. Kh nng hp th N v P ca c Vetiver rt cao so vi cc cy c khc.Error! Bookmark not d

Hnh 4.5. Hm lng thuc tr c trong t pha trc v sau hng c Vetiver.Error! Bookmark not de Hnh 4.6. Kim sot xi mn v x l nc thi cc m nui c nc ngt ng bng sng Cu Long. Error! Bookmark not defined. 8

Hnh 4.7. C Vetiver Bc N inh (tri) v Bc Giang (phi).Error! Bookmark not defined. Hnh 4.9. Vng t ngp nc trng c Vetiver (tri) v x l nc thi thm r t bi rc (phi) xtralia. Error! Bookmark not defined. Hnh 4.10. C Vetiver trng bi ly nc thi t tri ln Bin Ha (tri) v Trung Quc (phi). Error! Bookmark not defined. Hnh 4.11. S b tr x l nc thi sinh hot bng c Vetiver.Error! Bookmark not defined. Hnh 4.12. M hnh lc nc thi bng cc lung c Vetiver.Error! Bookmark not defined. Hnh 4.13. C Vetiver chu ng c pH=3,8; Al bo ha 68%-87% trong t.Error! Bookmark not Hnh 4.14. pH=3,3 v hm lng Mn cc k cao, ti 578mg/kg, c Vetiver vn sinh trng v pht trin tt. Error! Bookmark not defined. Hnh 4.15. C Vetiver thch nghi rt tt vi t c mn cao.Error! Bookmark not defined.

Hnh 4.8. Hiu qu ca c Vetiver tiu gim N it trong nc thi sinh hot.Error! Bookmark not defined

Hnh 4.16. Phc hi m than stralia (tri) v m bxit Venezuela (phi).Error! Bookmark not defin

Hnh 5.1. Dng chy mnh lm cc cy c bn a ng rp nhng hng c Vetiver vn ng thng, gp phn lm chm dng chy v gim nh xi mn.Error! Bookmark not def Hnh 5.2. B t p theo ng ng mc trn sn dc (tri trn) gp phn li dng chy ra ni khc (tri di). Hng ro c Vetiver dn dn cng to nn cc b t (phi trn) nhng vn cho nc mt chy chm v dn u trn sn dc (phi di), qua gim nh ra tri, xi mn v nc mt ngm nhiu hn, su hn xung di t (Greenfield 1989). Error! Bookmark not defined.

Hnh 5.3. Ph sa mu m c gi li khi nc l chy qua cc hng c Vetiver Darling Downs, xtralia (tri) v cho v cao lng bi thu (phi).Error! Bookmark not define Hnh 5.4. Trng c Vetiver gim nh xi mn, ra tri v ph lung vng ch Tata, min N am n . Error! Bookmark not defined. Hnh 5.5. Vn trng: trng c Vetiver trn t dc 50o (d n gim ngho ng Bali, Phillipin). Error! Bookmark not defined. Hnh 5.6. Trng c Vetiver gim nh ra tri, xi mn v ph lung trn cc n in c ph Ty N guyn. Error! Bookmark not defined. Hnh 5.7. Trng c Vetiver gim nh ra tri, xi mn, gim dc a hnh v ci to t trong d n trng sn min Bc Vit N am.Error! Bookmark not defined. Hnh 5.8. Su c thn (Chilo partellus). Error! Bookmark not defined.

Hnh 5.9. C s l thuyt ca bin php trng c Vetiver phng tr su bnh cho hoa mu: thu ht su bnh ti trng ni chng t c kh nng sng st.Error! Bookmark not d Hnh 5.11. Trng c Vetiver tr su c thn cho ng Zulu, N am Phi.Error! Bookmark not defined. Hnh 5.12. C Vetiver non c th l ngun thc n cho tru b.Error! Bookmark not defined. Hnh 5.13. Bo v cc n ct mt khu ngh dng Senegal (Mamadou Sy).Error! Bookmark not de

Hnh 5.10. Su c thn non t c kh nng sng st trn l c Vetiver c lng.Error! Bookmark not defi

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Hnh 5.14. R c Vetiver c th xuyn qua lp kim vi cng ht nc di su gip c sinh trng tt. Cc loi cy khc nh ng v nho khng lm c nh th v s cht nu khng c ti. Error! Bookmark not defined. Hnh 5.15. t ct lc ban u (tri); cng y sau khi ci to bng cch ph mt bng thn, l c Vetiver c trng nho (phi).Error! Bookmark not defined. Hnh 5.16. N n ng trn t chua phn nng Tin Giang trc v sau khi trng c Vetiver. Error! Bookmark not defined.

Hnh 5.17. Bo v m tm cnh mng thot l t ng ra sng Vnh in ( N ng) - d n th nghim do i s qun H Lan ti Vit N am ti tr.Error! Bookmark not de Hnh 5.18. Bo v ngn mn h lu sng Tr Bng, Qung N gi.Error! Bookmark not defined. Hnh 5.19. ng nng thn Qung N gi. N a bn phi nh c c Vetiver bo v, na bn tri i chng. Error! Bookmark not defined. Hnh 5.20. th cng m ngh t c Vetiver ca Thi Lan.Error! Bookmark not defined. Hnh 5.21. th cng m ngh t c Vetiver ca Venezuela.Error! Bookmark not defined. Hnh 5.22. T tri sang phi: lu lp l c Vetiver Fiji, i hc Tng hp Cn Th v Zimbabwe Error! Bookmark not defined. Hnh 5.23. N h lp l c Vetiver Venezuela. Error! Bookmark not defined. Hnh 5.24. Trng c Vetiver gia c mt on b k g dc sng (tri) v l c c ct ra, phi kh lm lt buc la (phi). Error! Bookmark not defined. Hnh 5.25. Trng c Vetiver ven h nc ngoi Brisbane, xtralia.Error! Bookmark not defined.

Hnh 5.26. C Vetiver lm cy cnh xtralia, Trung Quc v Vit N am.Error! Bookmark not defined.

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LI GII THIU Bng c vetiver - gii php tin cy, hiu qu, thn thin vi mi trngKhng c nhiu loi cy va c o, a nng, va kinh t, hiu qu, thn thin vi mi trng, li n gin nh cy c Vetiver. Khng c nhiu loi cy tng c s dng mt cch lng l t hng trm nm nay, ri bng nhin c ph bin, ng dng rng ri v nhanh chng n vy trong vng 20 nm tr li y trn khp th gii, nh cy c Vetiver. V chc cng khng c nhiu loi cy c t cho nhiu ci tn thn thng, tru mn nh cy c Vetiver: no l cy c l tng, cy c c o, cy c thn diu, cy c a nng v.v., ri th bc tng sng, hng ro sng, neo t sng v.v. Bng c Vetiver (Vetiver System) s dng mt loi cy nhit i rt c o, c Vetiver Vetiveria zizanioides - gn y c phn loi li l Chrysopogon zizanioides. N u trng ng cch, c Vetiver c th mc trn rt nhiu loi t v trong rt nhiu iu kin kh hu khc nhau, c bit l iu kin kh hu nhit i v cn nhit i. N c rt nhiu c tnh c o, him khi cng thy ring mt loi thc vt no . N hng c tnh th hin r nt nht khi c Vetiver c trng thnh nhng bng c ken dy, iu cc k quan trng trong hu ht cc ng dng ca bng c Vetiver. C Vetiver Vetiveria zizanioides, hin c s dng vo nhng mc ch ht sc khc nhau gn 100 nc trn th gii, c ngun gc t N am n . N khng kt ht, khng lan truyn ba bi v phi trng bng hom khi mun nhn rng. C nhiu phng php nhn ging, nhng nhn bng hom r trn l n gin nht, t mt hom c th c ti 30-40 nhnh ch sau 3-4 thng. N hng nhnh ny sau c tch ra thnh cc hom mi (khong 23 nhnh mt hom) v c trng cch nhau khong 10-15 cm, thnh hng dc theo cc ng ng mc a hnh. N h th, khi ln s to thnh cc bng c dy, rm, lm chm v phn tn u nc chy trn b mt sn dc, ngn chn ra tri bn t, gim nh xi mn. Mt hng c trng thnh c th gim ti 70% nc chy b mt v ti 90% bn t ra tri. Bn t b chn li pha sau cc hng c, lu dn s to nn cc bc thang, lm thoi dn a hnh sn dc. Bin php ny rt n gin, s dng lao ng th cng, chi ph thp nhng li rt hiu qu. Khi dng bo v cc cng trnh c s h tng, chi ph ca bin php ny ch bng khong 1/20 so vi cc bin php cng trnh truyn thng. nhiu nc, cc nh k thut gi y l cc neo t sng, v b r s, n su ca c Vetiver rt khe, c sc khng ko trung bnh ti 1/6 sc khng ko ca thp. C Vetiver c th trng thu hoch trc tip nh mt loi nng sn nhng hng lot nghin cu th nghim v ng dng i tr trong 20 nm qua nhiu nc trn th gii cn cho thy, cy c Vetiver c bit c hiu qu trong cc lnh vc phng trnh, gim nh thin tai (l lt, xi mn, trt l, st l t dc, xi l b sng, b bin, bo v taluy ng, b knh mng, p v.v.), bo v cc lu vc sng, cc rng u ngun, bo v mi trng (gim nh nhim t v nc, x l nc thi, rc thi, d lng thuc tr su, thuc bo v thc vt, ci thin cht t v.v.), cha k hng lot ng dng khc. Tt c nhng ng dng k trn, di hnh thc bo v hoc ci thin t ai, bo v c s h tng, hoc cung cp cc dng nng sn, u trc tip hoc gin tip tc ng n cuc sng ca cc h dn ngho nng thn. 11

Bng c Vetiver c th s dng trong hu ht cc lnh vc lin quan n pht trin nng thn v pht trin cng ng. Cng ngh ny cn c ph bin v ng dng mt cch thch hp trong cc k hoch pht trin cng ng, a phng hoc khu vc, to cng n vic lm cho cc t chc, c nhn cc a phng, t cc khu sn xut, cung cp cy ging, n trin khai bo v mi trng, gim nh thin tai, hoc lm cc mt hng th cng, m ngh, lm vt liu ph lung, lp nh, lm thc n cho gia sc v.v. N i cch khc, y chnh l cng ngh c th gp phn gim ngho ng k i vi mt b phn ln cng ng. Bng c Vetiver thuc v cng ng v ai cng c th chia s mi thng tin v cng ngh ny. Tim nng ng dng Vetiver l rt ln v nhng hiu bit v cy c ny cn c ph bin rng ri hn, y hn trong x hi. Mng li Vetiver Quc t nhn thy rng y vn cn mt s kh khn, quan ngi, lng l, thm ch nghi ng v cc gi tr cng nh hiu qu ca cy c Vetiver. Tuy nhin, phn ln cc trng hp ng dng c Vetiver cha t kt qu mong mun l do cha hiu bit hoc cha c hng dn y v cy c ny. y l mt cun cN m nang tng hp, chi tit v thc tin, xut pht t cc hot ng nghin cu, ng dng Vit N am v nhiu ni khc trn th gii. Cun sch c bin son ng thi bng c hai th ting Anh v Vit v Mng li Vetiver Quc t cng nhn c cam kt dch sang cc th ting khc nh Trung Quc, Ty Ban N ha v Php. Ti tin rng cun cN m nang s c n c bi tt c nhng ai s dng hoc tuyn truyn, c sy cho vic s dng bng c Vetiver. Thay mt Mng li Vetiver Quc t, ti xin chn thnh cm n tp th tc gi v nhng ng gp to ln ca h. Dick Grimshaw N gi sng lp v Ch tch Mng li Vetiver Quc t (TVN I).

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LI NI UC Vetiver tng c du nhp vo Vit N am t kh lu nhng ch yu ch sn xut tinh du. Vi mc ch gp phn gim nh xi mn trn t dc Vit N am, nm 1998, ng Ken Crismier (Mng li Vetiver Quc t - The Vetiver N etwork International - TVN I) dch cun sch C Vetiver - hng ro chng xi mn (Vetiver grass - the hedge against erosion) ca N gn hng Th gii sang ting Vit v h tr kinh ph N h Xut bn N ng nghip pht hnh 5.000 bn. N m 1999, cng vi s gip ca ng Ken Crismier, B N ng nghip v Pht trin N ng thn mi TS. Paul Trng (xtralia) v TS. Diti Hengchaovanich (Thi Lan) sang Vit N am gii thiu v cy c ny trong mt lot hi tho H N i, N gh An v Thnh ph H Ch Minh. TS. Paul Trng cn gip xin c mt s c ging t Thi Lan trng th nghim Vit N am. Mng li Vetiver Vit N am (Vietnam Vetiver N etwork - VN VN ) c thnh lp t nm 1999 do ng Ken Crismier lm iu phi vin. T 2001 n 2003 v t 2003 n nay, cng vic ny ln lt do TS. Phm Hng c Phc (i hc N ng lm Thnh ph H Ch Minh) v TS. Trn Tn Vn (Vin Khoa hc a cht v Khong sn, B Ti nguyn v Mi trng) m nhn. Sau mt s ng dng th nghim thnh cng (GS. Thi Phin v ng nghip Vin Th nhng N ng ha (B N ng nghip v Pht trin N ng thn), TS. Phm Hng c Phc v ng nghip Cng ty Thin Sinh v Binh on 16, TS. L Vit Dng v ng nghip i hc Tng hp Cn Th, TS. Trn Tn Vn v ng nghip v.v.) th c Vetiver c ng dng rng ri Vit N am. Cc B N ng nghip v Pht trin N ng thn v Giao thng Vn ti ln lt ra quyt nh (s 4727/Q/BN N -KHCN ngy 8/10/2001, s 3553/Q-BGTVT ngy 31/10/2002 v s 241/Q-BGTVT ngy 24/01/2005) cho php s dng c Vetiver gim nh thin tai, bo v c s h tng. Hng lot d n nghin cu hoc ng dng, th nghim hoc i tr c trin khai, trong c nhng d n quy m rt ln nh bo v taluy ng H Ch Minh, bo v sng An Giang, Qung N gi, bo v bin Hi Hu (N am nh) v.v. T nm 2003, c Vetiver v ang c th nghim trong x l nhim t v nc, x l nc thi, rc thi, bo v mi trng mt s a phng nh Bc Giang, Bc N inh, Thi Bnh, Tha Thin-Hu, ng N ai, Cn Th, An Giang v.v. n nay, c Vetiver c bit n v c s dng gn 40 tnh thnh trong c nc. TVN I nh gi rt cao tc pht trin v nhng kt qu t c trong vic nghin cu, ng dng c Vetiver Vit N am, v ti Hi ngh Quc t ln th 4 v c Vetiver (ICV-4) din ra ti Caracas, Venezuela (22-26/10/2006), TVN I trao nhng gii thng ln nht cho VN VN : gii Qun qun Vetiver (Vetiver Champion), gii Gim nh Thin tai (Disaster Mitigation Prize) v bng Chng nhn Trnh Cp 1 (Certificate of Technical Excellence Class 1). Cun cN m nang C Vetiver - hng ro chng xi mn k trn do tc gi John Greenfield bin son v c N gn hng Th gii xut bn ln u tin nm 1987. ng nh tn gi ca n, cun sch ch yu hng dn v k thut ng dng c Vetiver chng xi mn trn t dc. T n nay c 20 nm v c Vetiver c ng dng rng ri trong rt nhiu lnh vc khc, c bit l trong gim nh thin tai v bo v mi trng. Trn c s tng hp mt s lng s cc kt qu nghin cu v ng dng c Vetiver

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trn th gii v Vit N am, tp th tc gi nhn thy n lc cn bin son mt cun cN m nang mi, chi tit hn, vi nhiu ng dng hn, thay cho cun sch xut bn trc y ca N gn hng Th gii. Tp th tc gi trao i v tng ny v nhn c s ng h nhit thnh ca Mng li Vetiver Quc t. Cun sch hng ti i tng ng o l cc k s, nh qun l v cc nh xy dng chnh sch trong cc lnh vc xy dng, giao thng, thy li, nng nghip, phng chng thin tai, bo v mi trng v.v., cng nh cc cng ng a phng. Lin hip cc hi Khoa hc v K thut Vit N am (VUSTA) lp Hi ng thN m nh bn tho cun sch theo Quyt nh s 1457/Q-LHH ngy 31/10/2006. Cun sch chc chn cn c mt s li k thut v t ng m do hn ch v nng lc v thi gian, tp th tc gi cha kp hon thin. Rt mong c bn c lng th v gp kin cc ln ti bn sau c hon thin hn. Mi gp , trao i xin lin h vi TS. Trn Tn Vn, Vin Khoa hc a cht v Khong sn, Thanh Xun, H N i, Vit N am. Tel: 84-4-8547335; Fax: 84-4-854-2125; Email: van@rigmr.org.vn; van@vigmr.vn; trantv@gmail.com. Paul Trng, Trn Tn Vn v Elise Pinners.

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LI CM NMng li Vetiver Vit N am xin chn thnh cm n: i s qun Vng quc H Lan ti Vit N am v Trng i hc Thy li H N i h tr v to iu kin cho vic bin son v xut bn cun sch ny; Qu Donner, Qu Di truyn Wallace ca Hoa K, Qu Ambertone Trust ca Vng quc Anh, Chnh ph an Mch, i s qun Vng quc H Lan ti Vit N am v Mng li Vetiver Quc t h tr v khuyn khch hu ht cc cng trnh nghin cu v pht trin (R&D) nu trong cun sch ny; S gip v ng h ca Trng i hc Tng hp Cn Th v Gio s Hiu trng L Quang Minh; Trng i hc N ng lm Thnh ph H Ch Minh; B Ti nguyn v Mi trng; c bit l Lin hip cc hi Khoa hc v K thut Vit N am (VUSTA) - c quan t chc thN m nh v nh gi phin bn ting Vit ca cun sch ny; S c v v gip nhit tnh ca rt nhiu ngi hin ang nghin cu v ng dng c Vetiver Vit N am, c bit l cng sc ca dch gi Trn Cng T, cc ng nghip Lng Th Tut, N guyn Th Yn N gc v on Th Anh trong vic chuN n b phin bn ting Vit ca cun sch ny.

Cc s liu s dng trong cun sch ny khng nhng ch l kt qu nghin cu v trin khai ca cc tc gi m cn l ca cc bn ng nghip t khp ni trn th gii, nht l Vit N am trong my nm gn y: 1. n : L. Haridas; 2. Cng G (DRC): Dale Rachmeler, Alain N dona; 3. i Loan: Yue Wen Wang; 4. H Lan: Henk Jan Verhagen; 5. Indonesia: David Booth; 6. Lo: Werner Stur; 7. Mali v Senegal: Criss Juliard; 8. Mng li Vetiver Quc t (TVNI): Bob Adams, Mark Dafforn, John Greenfield, Dick Grimshaw, Criss Juliard, Mike Pease, Dale Rachmeler, Joan & Jim Smyle; 9. Nam Phi: Johnnie van den Berg, Roley N ofke; 10. xtralia: Ralph Ash, Bruce Carey, Errol Copley, Darryl Evans, Barbara & Ron Hart, Jim Klein, Clive Knowles-Jackson, Frank Mason, Peter Pearce, Ian Percy, Cameron Smeal, Bill Steentsma; 11. Philippin: Eddie Balbarino, N oah Manarang; 12. Thi Lan: N arong Chomchalow, Diti Hengchaovanich, Reinhardt Howeler, Suwanna Parisi, Surapol Sanguankaeo, Department of Land Development, Royal Project Development Board; 13. Trung Quc: Liyu Xu, Hanping Xia, Liao Xindi, Wensheng Shu;

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14. Vit Nam: Cc cng ty Thin Sinh (KS. Trn N gc Lm) v Thin An (KS. L Tun An), nh thu d n trng c Vetiver gim nh xi mn, bo v taluy ng H Ch Minh; Cng ty Kellogg Brown Root (KBR), nh thu chnh trong D n gim nh thin tai tnh Qung N gi do AusAid ti tr: ng Ian Sobey; i hc Tng hp Cn Th: L Vn B, Lu Thi Danh, TS. L Vit Dng, L Vn Hon, N guyn Vn M, Dng Minh, L Tn Phong; i hc N ng lm Thnh ph H Ch Minh: TS. L Vn D, TS. Phm Hng c Phc; Trung tm Khuyn nng Qung N gi: KS. V Thanh Thy.

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Phn 1 CY C VETIVER1. GII THIU Bng c Vetiver (Vetiver System - VS) do N gn hng Th gii trin khai ln u tin t gia nhng nm 80 ca th k trc ti n nhm gi t v nc bng cch s dng c Vetiver (tn khoa hc l Vetiveria zizanioides L., mi i li l Chrysopogon zizanioides L.). N hng ng dng ny hin nay vn gi vai tr rt quan trng trong sn xut nng nghip. Tuy nhin, mt lot kt qu nghin cu - pht trin trong hn 20 nm qua chng minh thm rng, do nhng c im c o ca cy c Vetiver, bng c Vetiver ngy nay cn c th s dng nh mt bin php k thut - sinh hc (bio-engineering) nhm n nh t cc sn dc, mi dc, x l nc thi, x l nhng vng t nhim v ci thin mi trng v.v. Bng c Vetiver l bin php s dng thc vt rt n gin, d lm, rt thn thin vi mi trng, khng tn km, t tn cng duy tu bo dng nhng li rt hiu qu trong vic gi t, gi nc, hn ch ra tri, xi mn, n nh, phc hi v ci thin cht lng t. C Vetiver c trng theo hng, to thnh nhng b ro kn lm chm tc nc chy, phn tn rng nc mt chy trn, hn ch ra tri, xi mn, gi N m cho t v tch t t cng nh phn bn, thuc tr su vo nhng ch nht nh. Do nhng tnh cht c o v hnh thi v sinh l nh s trnh by di y, cc bng c ny tt hn hn cc loi b ro bng cht liu khc tng c nghin cu, th nghim. N goi ra, c Vetiver cn c b r rt pht trin, n su v gn kt cht vi t, khin t kh b r, ngay c khi chu tc ng ca dng nc chy xit. B r n su v pht trin rt nhanh ca c Vetiver cn gip n chu hn rt tt v gi cho nhng sn t dc b st l. 2. MT S C IM CHNH CA C VETIVER 2.1. c im hnh thi C Vetiver khng c thn ngm, nhng b r s ca n pht trin rt nhanh, trong nhng iu kin thch hp th ngay trong nm u tin r c th n su ti 3 - 4m. N h , n c kh nng chu hn c bit v gip hn ch xi mn t ngay c khi c dng nc xit chy qua. Phn thn trn mt t ca c Vetiver mc thng ng v rt cng, chc. Khi c trng dy, c s mc st vi nhau to thnh mt hng ro kn, gip n chu c dng nc chy xit, hn ch xi mn t v phn tn nc mt chy trn rt hiu qu (Hnh 1.1). N hng chi non pht trin t phn c r nm di mt t gip c Vetiver chng chu c la chy, sng, gi, s gim p ca ngi i li v chn th gia sc. Sc chng chu su bnh cao. Khi b bn t lp, r mi c th mc ra t nhng on thn pha trn v c Vetiver tip tc pht trin v pht huy tc dng. C th, mt lp t dy c th tch li pha trc bng c, gip gim nh xi mn, ra tri bn t.

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2.2. c im sinh l C Vetiver chu c nhng bin i ln v kh hu nh hn hn, ngp ng v khong dao ng nhit rt rng, t -22oC n 55oC. Sau khi b tc hi bi kh hn, sng gi, ngp mn v nhng iu kin bt thun khc, khi thi tit tt tr li v t c ci to, c Vetiver c kh nng phc hi li rt nhanh. C Vetiver c th thch nghi c vi rt nhiu loi t c pH dao ng t 3,3 n 12,5 m khng cn n bin php ci to t no (Hnh 1.2-4). C Vetiver c kh nng chng chu rt cao i vi cc loi thuc tr su, thuc dit c v.v. C Vetiver c kh nng hp th rt cao cc cht ha tan trong nc nh N it (N ), Phtpho (P) v cc nguyn t kim loi nng c trong nc b nhim. C Vetiver c kh nng chng chu rt cao i vi cc loi thuc tr su, thuc dit c v.v. C Vetiver c th mc tt trn nhiu loi t chua phn, t kim, t mn v t cha nhiu N a, Mg, Al, Mn hoc cc kim loi nng nh As, Cd, Cr, N i, Pb, Hg, Se v Zn.

2.3. c im sinh thi Mc d c nhng kh nng c o nu trn, nhng v l ging c in hnh ca min nhit i nn c Vetiver khng chu c bng rm. Bng rm lm gim kh nng sinh trng v pht trin ca c, thm ch c th lm cho n li i. V vy, tt nht l nn trng c Vetiver ni t trng, khng b cc loi thc vt khc che ph, thm ch khi mi trng c th cn phi tr c di. Khi trng nhng ni nn t khng n nh, d b st l, xi mn, c Vetiver trc ht gip hn ch c st l, xi mn, tin ti n nh nn t (c bit l ni t dc), tip gip ci thin iu kin mi trng, vi kh hu, sau c th trng c nhng loi cy khc m ta mun. Vi nhng c im , c th coi c Vetiver nh l ging cy tin phong nhng vng t xu.

2.4. Kh nng chu lnh ca c VetiverMc d l mt loi thc vt nhit i, nhng c Vetiver vn c th sng c nhng ni rt lnh. Khi ch c ngn c b tp, cn nhng im sinh trng ngm di t ca n vn sng. xtralia, khi nhit xung n -14oC, c Vetiver vn sinh trng v pht trin. min Bc Trung Quc, n vn sng c trong thi gian ngn khi nhit xung n -22oC. Cn Georgia (Hoa K), c Vetiver c th sng -10oC, v ch cht khi nhit xung n 15oC. N hng nghin cu gn y cho thy nhit t ti u cho r c Vetiver pht trin l 25 C. nhit t 15oC, vn c mt s t chi non nh ra v 13oC, r vn mc thm 12,6cm/ngy. N h vy l c Vetiver khng ng ng nhit ny, v bng phng php ngoi suy c th bit hin tng ngh ng xy ra khi nhit xung khong 5oC (Hnh 1.5).o

Kh nng thch nghi ca c Vetiver c nu tm tt Bng 1.1. 2.5. c im di truyn 18

Hin c 3 ging c Vetiver c trng gi t. 2.5.1. Ging Vetiveria zizanioides L (tn mi: Chrysopogon zizanioides L) n c 2 dng V. zizanioides l: Dng Bc n, d sinh, c ra hoa kt ht; v Dng N am n, khng hoc rt t ra hoa kt ht.

Dng Bc n mc hoang nhng vng m ly ngp nc Bc n , ch yu ly tinh du, khng dng gi t. Dng N am n ch yu ly tinh du v c th trng gi t v nc nhiu ni trn th gii nh c nhng c im c o nh nu trn. Kt qu nghin cu gn y ca Chng trnh xc nh ADN cho thy, trong s 60 mu ly t 29 nc thuc Bc M, N am M, Chu , Chu i Dng v Chu Phi (tc l ngoi vng N am ) c 53 mu (88%) thuc v dng V. zizanioides v tnh. Tt nht trong s ny l ging Monto (xtralia), ging Sunshine (Hoa K), ging Vallonia (N am Phi) v ging Guiyang (Trung Quc). iu c ngha l mi kt qu nghin cu, pht trin v ng dng trn ton th gii u c th c chia s v u da trn cng mt ging c. Th d, mi kt qu t c xtralia ch yu u t ging Monto, v u c th c s dng mt cch hon ton tin cy Vit N am khi ging ny cng c trng Vit N am. Ging c Vetiver hin c trng rng ri Vit N am c ngun gc t Phillipin hoc Thi Lan v thuc dng N am n, khng ra hoa kt ht v ngi ta thng gi l c Vetiver.Bng 1.1. Kh nng thch nghi ca c Vetiver mt s nciu kin bt thun Cht t pH mn (gim nng sut 50%) mn (cn sng) Hm lng nhm (% Al no) Hm lng Mangan (Mn) Hm lng Na Hm lng Mg xtralia 3,3-9,5 -1 17,5mScm 47,5mScm-1 Khong 68-87% >578 mgkg -1 48% (trao i Na) -1 2400mgkg (Mg) N v P, phn chung Mt s nc khc 4,2-12,5 (vi hm lng Al ha tan cao)

Phn bn C Vetiver pht trin c ni t kh cn N v P (300kg/ha NPK) v n cng sinh vi khun mycorrhiza. Kim loi nng Acsen (As) Cadmi (Cd) ng (Cu) Crm (Cr) Niken (Ni) Thy ngn (Hg) Ch (Pb) Selen (Se) Km (Zn) V tr a l iu kin kh hu Lng ma hng nm (mm) Lnh (nhit t) 100-250mgkg-1 -1 20mgkg 35-50mgkg-1 -1 200-600mgkg -1 50-100mgkg >6mgkg-1 >1500mgkg >74mgkg-1 -1

>750mgkg-1 15-37 v Nam 450-4000 -11oC 41 v Bc n 38 v Nam. 250 - 5000 -22oC

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iu kin bt thun Nng Hn hn (ma khng ng k) Lm thc n gia sc (l non)

xtralia 45oC 15 thng 55oC

Mt s nc khc

C th lm thc n cho b C th lm thc n cho b sa, sa, b tht, nga, th, cu, b tht, d, cu, ln, c chp. kanguru. N = 1,1% P = 0,17% K = 2,2% Protein th 3,3% Cht bo th 0,4% Cht x th 7,1%

Gi tr dinh dng

2.5.2. Ging Vetiveria nemoralis y l ging c th ra hoa kt ht, c ngun gc v mc rng ri cc vng ni cao Thi Lan, Lo, Vit N am, c th c Campuchia v Mianma na. Thi Lan, n ch yu dng lp nh. Khc bit chnh gia ging V. zizanioides v ging V. nemoralis l ging V. zizanioides mc cao, to, thn cng v khe hn, b r dy hn v mc su hn, l rng hn v c sng mu xanh nht gia (Hnh 1.6-10). Mc d ging V. nemoralis hiu qu khng cao nh ging V. zizanioides nhng ngi dn mt s tnh ven bin Min Trung Vit N am (ting a phng gi l C ) v Ty N guyn t lu bit ch li ca n v trng gi cho b rung la c vng chc. 2.5.3. Ging Vetiveria nigritana Ging c ny c ngun gc t Ty Phi v N am Phi, c th ra hoa, kt ht. Phm vi s dng v phn b ca n ch hn ch lc a ny (Hnh 1.11). 2.6. Kh nng tr thnh c di Mt yu cu bt buc trong cng ngh sinh hc l mi ging cy c c s dng u khng c php tr thnh c di, gy hi cho mi trng. Vetiver l ging c khng tham lam, khng xm hi n cc cy c khc. N khng c thn b ngang, cng khng c thn r m ch pht trin bng cch sinh sn v tnh t r hoc hom, do vy n hon ton p ng c yu cu nu trn. C Vetiver c du nhp vo o Fiji t hn 100 nm nay, c s dng gi t v nc t hn 50 nm nay v n cng khng tr thnh c di mi trng mi ny. Khi cn thit, c th tr c Vetiver bng cch phun Glyphosate hoc o r ln v phi kh. Tm li, vi nhng c im hnh thi, sinh l, sinh thi ph hp, kh nng thch nghi tt vi nhng iu kin thi tit khc nghit m li khng c kh nng tr thnh c di, c Vetiver ngy nay c s dng rng ri nh mt bin php k thut sinh hc (bioengineering) nhm n nh t cc sn dc, mi dc, x l nc thi, x l nhng vng t nhim v ci thin mi trng v.v. Tuy nhin, cn phn bit chnh xc cc ging c Vetiver khc nhau v chng ti xin khuyn co l ch nn s dng ging V. zizanioides vo nhng mc ch ny. Ging c (V. nemoralis) mc d c th l ging bn a Vit N am nhng kh nng pht trin khng cao v quan trng hn, b r ca n ngn, khng thch hp n nh nhng sn t dc. Hn na, cng cha c cng trnh nghin cu no v kh nng ca n trong x l nc thi, phc hi v ci thin mi trng.

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Hnh 1.1. C mc thng ng, rt cao v cng, to thnh hng ro ngn cn ra tri t.

Hnh 1.2. C Vetiver chu chy rt tt, ch hai thng sau, khi c ma phc hi tr li.

Hnh 1.3. C Vetiver trng trn ct ven bin Qung Bnh (tri) v t chua phn G Cng (phi).

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Hnh 1.4. C Vetiver trn t chua phn nng Tn An (tri) v t kim nng vng kh nng Ninh Thun (phi). Cc dng: VVZ008-18, hito v i Loan. Hai dng sau tng t nh dng Sunshine. X l nhit : ban ngy 15oC, ban m 13oC. (Y.W. Wang)

Hnh 1.5. nh hng ca nhit t ti kh nng pht trin r c Vetiver.

Hnh 1.6. L c Vetiver: Vetiveria zizanioides (tri) v V. nemoralis (phi).

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V. nemoralisHnh 1.7. Cy c Vetiveria nemoralis (trn) v Vetiveria zizanioides (phi).

V. zizanioides

V. zizanioides

V. nemoralisHnh 1.8. R c Vetiver: Vetiveria nemoralis (di) v Vetiveria zizanioides (trn).

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Hnh 1.9. R c Vetiver trong t (tri v gia) v trong nc (phi).

Hnh 1.10. Tri: Vetiveria nemoralis (c ) Qung Ngi; phi: Ty Nguyn.

Hnh 1.11. Vetiveria nigritana Mali, Ty Phi.

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Phn 2 NHN GING C VETIVER1. GII THIU pht trin bng c Vetiver, cn mt lng cy ging rt ln v cht lng cy ging l iu kin tin quyt m bo cho s thnh cng ca h thng ny. V vy, rt cn to lp nhng vn m c kh nng cung cp mt lng ln c ging cht lng cao v gi thnh h. Mng li Vetiver Quc t khuyn co nn dng ging c Vetiver khng ra hoa kt ht trnh hin tng bin thnh c di trong mi trng mi. N hng th nghim ADN cho thy nhng ging c Vetiver khng ra hoa kt ht c s dng rng khp trn th gii u c tnh di truyn tng t nh ging Sunshine ca Hoa K v ging Monto ca xtralia. N hng ging ny u c ngun gc xut x t n . V khng c ht ging nn vic nhn ging phi thc hin bng phng php v tnh. 2. VN M vn m c th nhn ging c Vetiver bng hom v bng phng php cy m. Di y l mt s yu cu cn thit xy dng k hoch v to lp mt vn m ging c Vetiver cho nng sut cao v d qun l: Cht t: Tt nht l dng t ct pha hoc t nhiu mn d nh, t gy tn thng cho r v c r. Cng c th dng t tht pha nhng khng nn dng t tht nng. a hnh: C Vetiver khi trng thnh c th pht trin tt ni ngp nc. Khi mi trng, c non d b ci cc do nc ng. V vy, nn chn ni t hi dc trnh ng nc khi c ma hoc khi ti qu nhiu nc. Cng c th m c ging ni t bng nhng lu trnh ng nc, nh hng n s sinh trng v pht trin ca cy con. Bng rm: C nh hng xu n s sinh trng, pht trin ca c Vetiver, v vy nn m ni t trng. Cng c th m ni khng hon ton b che ph bi bng rm. Trng c vn m: Hom ging hoc cy con cn trng dy thnh hng theo ng ng mc d s dng my mc khi thu hoch. Ti nc: N n s dng h thng phun ti c u trong nhng thng u tin. V sau, khi c ln th c th ti ngp chn. Thu hoch: Khi c trng thnh (3-5 thng sau khi trng), c th thu hoch bng tay hoc bng my. N u dng my, cn o r su 20-25cm di mt t, trnh khng lm tn thng phn c r ca c. Mun vy, tt nht l nn dng cy mt li hoc cy mt a c th iu chnh d dng (Hnh 2.1). S dng cc loi my mc: nhng vn m quy m ln, c th dng my cy c iu chnh trng c Vetiver. C th s dng mt s loi my nng nghip khc nh my to lung, my lm c, my ct, my thu hoch. Hng dn k thut: Mun m c Vetiver t hiu qu cao cn hng dn k thut y cho i ng cn b, cng nhn chm sc vn m. 25

3. NHN GING C 4 phng php thng c dng nhn ging c Vetiver: Tch khm trng thnh thnh nhiu cy trng r trn. N hn ging t cc b phn ca cy m. Trng bng chi hoc nui cy chi trong ng nghim c s lng ln cy ging. N ui cy m t mt phn ca cy m nhn c nhiu cy ging.

3.1. Tch khm trng r trn Tch khm c m mt cch cN n thn, nh nhng thnh tng dnh nh, mi dnh c 2-3 nhnh c. Ct b phn thn l bn trn, ch li mt on khong 15cm, ct bt cc on r tha, trnh lm tn thng phn c r (Hnh 2.2). Trc khi trng, nu c th nn nhng cc dnh c trn vo hocmn, vo phn chung hoai hoc t bn pha sn st gi N m v kch thch ra r. C ging cha trng ngay c th t vng nc nng di nh nng mt tri m bo t l sng cao trc khi trng ra din rng (Hnh 2.3). 3.2. Nhn ging t cc b phn ca cy m C 3 b phn ca cy c Vetiver trng thnh c th dng nhn ging l (Hnh 2.4-5): Dnh c; C r hoc gc cy; Hom.

Hom c th ly t thn hoc gc cy. Chn hom t nhng thn c, chc, khe, c t t r v chi non c th mc khi c N m. Hom c th t nm hoc cm thng ng vo ct N m hoc mi trng c phun sng thc cho r v chi non sm xut hin mi t. TS. L Vn D i hc N ng Lm Thnh ph H Ch Minh nhn ging c Vetiver theo 4 bc sau: ChuN n b hom ging; Phun dung dch bo ty 10% (Hnh 2.6); Ph kn hom ging bng ti nilon trong vng 24 gi (Hnh 2.7); em hom trng trn lung bn phn chung. 3.2.1. Chun b ging Hom: Chn nhng thn c Vetiver trng thnh v c nhiu t v chi hn so vi cc thn non. Ct ly tng hom di 30-50mm, vt ct di t 10-20mm, bc ht l gi bao quanh bn ngoi. Thng thng, sau mt tun chi s mc ra. Cy: Chn nhng cy c Vetiver trng thnh, c t nht 3-4 l pht trin y . CN n thn tch tng nhnh r v c r b tn thng.

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C r: T b phn ny ca cy c Vetiver trng thnh s mc ra cc mm. Tt nht l s dng phn trn ca c r mt cy c Vetiver trng thnh. 3.2.2. Phun dung dch bo ty 10% Dung dch bo ty c cha rt nhiu hocmn v cc cht kch thch sinh trng khc nh axit gibberellic, cc hp cht indol-axetic (IAA). Cch chuN n b dung dch bo ty nh sau: Bo ty ly t ao, h, sng, ngi v; Cho vo nhng ti nilon kn c dung tch 20lt; Khong 1 thng th bo ty hon ton hoai mc; Gn b phn cht rn, ch gi li phn nc; Ct gi dng dn. 3.2.3. X l v trng 3.2.4. u im v nhc im ca phng php trng bng r trn v hom u im: Rt hiu qu, t tn km v sm c cy ging trng; Khi lng cy ging gn nh, t tn cng vn chuyn; Rt d trng bng phng php th cng; C th trng bng my trn din tch ln. Nhc im: D b tn thng do b kh, nht l trong iu kin thi tit bt thun; Khng c hin trng lu trc khi trng; Phi trng trn t N m; Trong nhng tun u tin cn thng xuyn ti nc; N n trng trn t nh lung, ni tin nc ti.

3.3. Trng bng chi hoc nui cy chi trong ng nghim TS. L Vn B i hc Tng hp Cn Th p dng mt phng php nhn ging rt n gin v hiu qu (L Vn B et al., 2006). C 4 giai on ca phng php ny u c tin hnh trong mi trng lng: Kch thch m chi ngang; N hn thnh nhiu cy con; Thc cho cy con ra r; Thc cho cy pht trin nhanh di mi che hoc trong nh knh.

3.4. Nui cy m t mt phn ca cy m

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N ui cy m l phng php nhn ging trn quy m ln c nhiu cy c ging Vetiver. Phng php ny khng cn n mt s lng ln cy m, dnh hoc hom v l phng php rt quen thuc i vi cc nh sn xut rau, hoa, qu trn th gii. Cch lm c th khc nhau ty theo tng ni, nhng u ch s dng mt s rt t m ca cy c Vetiver, nui cy chng trong mi trng c bit, m bo v trng. N hng cy nh sinh ra c m trong mi trng thch hp cho n khi pht trin y thnh cy ging th em trng trn din rng (chi tit xin xem trong Truong, 2006). 4. CHUN BN TRNG Trong nhng iu kin bt thun, m bo c mc tt, v nhanh, t l sng cao, khi cy ging c sn xut theo nhng phng php nu trn tui trng thnh hoc s lng cn thit, c th tip tc chuN n b thm mt bc trc khi em trng trn din rng bng cch: Trng trong ti bu; v Trng thnh cc bng c.

4.1. Ti bu Cy con hoc dnh cy r trn trong chu hoc ti bu c cha na t trn vi na mn trong thi gian 3-6 tun ty theo iu kin nhit . Khi c t nht 3 chi non th em trng (Hnh 2.8-9). 4.2. Bng c Bng c l mt dng ti bu ci tin, c th cha c nhiu dnh r trn hoc gc ging, trng gn st bn nhau trn nhng lung di (khong 1m) chuN n b t trc, va d vn chuyn, va d trng. Cch lm ny tn sc lao ng, nht l nhng ni kh khn nh nhng sn dc cao; hn na, t l cy sng kh cao v r cy khng b xon gp hoc b li nh trng hp cho vo ti bu (Hnh 2.10). 4.2.1. u im ca vic s dng ti bu v bng c Sc chng chu cao, t b nh hng bi thay i nhit v N m; Gim bt cng ti nc sau khi trng; C pht trin nhanh sau khi trng; C th tm trc khi trng trong thi gian di hn ti a im trng; D p dng trong iu kin mi trng khng thun li. 4.2.2. Nhc im ca vic s dng ti bu v bng c Chi ph sn xut cao hn; Thi gian chuN n b lu hn, 4-5 tun hoc hn; Khi lng vn chuyn ln hn (chi ph cao hn); Chi ph chm sc trong khi ch i ti a im trng cao hn.

5. VN M C VETIVER VIT NAM

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Vit N am c rt nhiu ni lm thnh cng vn m c Vetiver (Hnh 2.11-14) v c t nhng vn m ny c s dng trng trong nhiu d n khc nhau trong nc v nhn rng ra cho nhiu c s khc.

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Hnh 2.1. Trng c Vetiver bng my (tri) v thu hoch bng tay (trn).

Hnh 2.2. Tch khm c Vetiver (di).

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Hnh 2.3. Tch khm (tri), nhng bn hoc phn chung chun b trng (phi).

Hnh 2.4. Dnh c Vetiver non (tri) v gi (phi) sn sng mang trng.

Hnh 2.5. C r hoc gc (tri) v hom c Vetiver (phi) sn sng mang trng.

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Hnh 2.6. Phun dung dch bo ty (10%) cho Hnh 2.7. Ph kn hom ging bng ti nilon c Vetiver ging. trong 24 gi.

Hnh 2.8. Trng trn lung c bn phn chung.

Hnh 2.9. R trn v ti bu (tri, gia) v ti bu sn sng mang trng (phi).

Hnh 2.10. Trng c trong cc bng (tri), ly ra khi bng (gia) v sn sng mang trng (phi).

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Hnh 2.11. Vn m i hc Cn Th (tri) v Tn Chu (An Giang) (phi).

Hnh 2.12. Vn m Qung Ngi (tri) v Bnh Phc (phi).

Hnh 2.13. Vn m Qung Bnh (tri) v Nng (phi).

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Hnh 2.14. Vn m Bc Ninh (tri) v Bc Giang (phi).

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Phn 3 TRNG C VETIVER GIM NH THIN TAI, BO V C S H TNG1. MT S DNG THIN TAI C TH GIM NH BNG C VETIVER Hin nay, trn th gii cng nh Vit N am, c Vetiver c ng dng hiu qu chng xi mn, ra tri trn cc sn t dc, ngoi ra n cn c s dng gim nh tc hi ca nhiu loi thin tai nh trt l, st l sn dc, taluy ng, xi l b sng, b knh mng, b bin, xi l, st l , p v.v. Vit N am, trong nhng nm va qua, nhiu trn ma ln gy ra hng lot nhng v trt l v l bn nhiu tnh min ni. Chng hn nh v trt l, l bn , l qut khng khip nm 1996 huyn Mng Lay (in Bin), v trt l cc ln trn o Hi Vn ( N ng) trong t ma l cui nm 1999 lm gin on giao thng Bc - N am trong hn na thng, chi ph khc phc tn trn 1 triu la M v.v. Trong s nhng im trt l ln nht Vit N am vi quy m ti hn 1 triu m3 t , c th k n im trt l cnh h Thit nh Bc (Hoi N hn, Bnh nh), hoc cc im trt khu vc cc x An N ghip v An Lnh (Tuy An, Ph Yn). Trt l khng nhng gy thit hi v ti sn, c s vt cht m nhiu khi cn gy cht ngi, cha k nhiu tn tht khc khng tnh m c v mi trng. Xi l b sng, b bin v h thng k bo v chng xy ra thng xuyn hu khp cc vng ca Vit N am. Mt s th d in hnh nh xi l b sng Ph Th, H N i, xi l b bin Hi Hu (N am nh), xi l b sng nhiu tnh ven bin Min Trung nh Tha Thin-Hu, Qung N am, Qung N gi, Bnh nh, xi l b sng, b bin cc tnh ng bng sng Cu Long v.v. N hng thin tai ny thng xy ra vo ma ma km theo l lt, nhng mt s ni nh thn Hu Vin (Cam L, Qung Tr), hoc ngay nh H N i, xi l b sng cng xy ra vo ma kh, khi mc nc sng cn nht. Trt l ang ngy cng xy ra ph bin hn nhng ni hot ng nhn sinh ang c trin khai rm r. Trn on ng H Ch Minh di hn 1.000km t H Tnh n Kon Tum c ti gn 200km , ang v c nguy c xy ra trt l nghim trng. N guyn nhn chnh c xc nh l do cha hiu bit y nhng c im a cht bt li khc phc chng khi thit k cng nh khi thi cng tuyn ng; hn na cn do trnh k thut thi cng, xy dng ng ca Vit N am vn cn nhiu hn ch. Mt lot s c trt l xy ra trong thi gian gn y ngay cc th x Yn Bi, Lo Cai, Bc Kn c xc nh l do ngi dn o xc chn dc, ly mt bng xy dng nh ca, to ra nhng vch taluy dng ng, lm mt n nh mi dc d gy trt l. N guyn nhn cui cng nhng khng km phn quan trng l, mc d khng ph bin nh nhiu nc khc, trt l Vit N am cng c khi xy ra do nhng trn ng t mnh, nh tng xy ra nm 1983 Tun Gio, hoc nm 2001 ngay ti th x in Bin v trn ng t in Bin i Lai Chu. Trt l khng ch gy ra nhng thit hi trc tip m cc bin php khc phc, x l hu qu cng rt tn km v N h nc thng khng c kinh ph cho nhng cng vic ny. 35

Chng hn, chi ph k bo v b sng thng tn 3-5 t ng/km, c khi ti 10-15 t ng/km, c bit k Tn Chu ng bng sng Cu Long mt ti gn 100 t ng/km. Chi ph k bo v ton b cc on xi l b sng ring tnh Qung Bnh c tnh ti hn 350 t ng trong khi ngn sch N h nc cp hng nm ch khong 5 t. p bin thng tn 10-15 t ng/km, nhng nhiu on cng ln ti 30-40 t ng/km. Sau khi cn bo s 7 thng 9/2005 lm h hi nhiu on bin, mt s nh qun l iu cn cho rng h thng bin s hin nay cng cha ly g lm vng chc, mi ch kh nng chng li gi bo cp 9. H cho rng cn xy dng h thng bin vng chc hn, kh nng chng li gi bo ti cp 12, vi chi ph ln ti 100-150 t ng/km. Hin nhin l ngn sch N h nc lun lun thiu v do vy, cng tc xy k p , bo v b sng, b bin thng mang nng tnh cc b, ch nhng ni xung yu nht, chc chn khng bao gi c bo v tt c nhng on b sng, b bin cn bo v. Tm li l sc ngi, sc ca nh b hn rt nhiu so vi thin tai, v vy n lc cn xem xt li chin lc phng chng thin tai truyn thng m trong ch ch trng nhng bin php cng trnh, cc b, cng nhc v tn km nh hin nay. Cc s c nu trn u l nhng th d in hnh ca hin tng mt n nh mi dc (hoc sn dc), khi t b ri di chuyn xui dc di tc ng ca trng lc. N hng dch chuyn ny c th din ra rt chm, kh nhn bit bng mt thng, nhng cng c th rt nhanh, ch trong vng mt vi pht hoc thm ch mt vi giy. C nhiu nguyn nhn gy ra cc dng thin tai ny, v do vy, gim nh tc hi ca chng, c bit l bng bin php k thut sinh hc - bng c Vetiver - ta cn lm quen vi mt s nguyn l n nh mi dc c bn. 2. MT S NGUYN L N NNH MI DC 2.1. Hnh thi mi dc Mt s sn dc un ln thoi v mm mi trong khi mt s khc li dc ng. Hnh thi ca nhng sn dc t nhin ph thuc ch yu vo kiu loi t v iu kin kh hu. Chng hn i vi t bn vng, c bit l cc vng kh, qu trnh bin i ha hc xy ra yu v chm hn nhiu so vi qu trnh bin i vt l. Do vy, nh dc thng hi li n gc cnh trong khi vch (mt thong) li gn nh dng ng, di chn c ng tch t l vi gc ngh (gc dc nht ti ng t b ri c th n nh) khong 30-35. N gc li, nu t km bn vng, c bit l cc vng N m, thng b bin i ha hc mnh v d b ra tri nn sn dc thng c lp t ph dy, nh vng ln trong khi chn dc li hi lm vo. 2.2. S n nh ca mi dc 2.2.1. Cc sn dc t nhin, taluy ng v.v. S n nh ca mi dc da trn tng tc gia hai loi lc, lc gy trt v lc khng trt. Lc gy trt thc N y vt liu di chuyn xui dc trong khi lc khng trt tc dng theo chiu ngc li. Khi lc gy trt thng c lc khng trt, mi dc tr nn mt n nh. 2.2.2. Xi l b sng, b bin v mt n nh cc cng trnh gi nc Mt s chuyn gia thy lc c th cho rng xi l b sng, b bin v mt n nh cc cng trnh gi nc cn c xem xt tch bit vi cc kiu mt n nh mi dc khc v

36

chng chu nhng tc ng khc. Tuy nhin, c th thy l chng cng da trn mt c ch chung l tng tc gia cc lc gy trt v lc khng trt nh trn. Trong thc t, c ch xi l b sng, b bin v mt n nh cc cng trnh , p c hi phc tp hn. l kt qu tng tc gia thy lc tc ng phn y v chn b hoc chn , p, v trng lc tc ng ln b hoc , p. Chng s tr nn mt n nh khi lng sng hoc b sng b xi dn, lm tng chiu cao hoc dc b, khin trng lc tr nn ln hn sc khng ct ca t to b. Bn t b xi l c th tch li ngay di chn b hoc lng sng, hoc c dng chy vn chuyn tip v pha h lu. Xi l b do dng chy thng xy ra di hai hnh thc, mt l xi l dn b mt v hai l trt c khi khi y sng chn b b xi qu mc khin b sng tr nn cao v dc hn. Ty thuc vo cc c tnh c l ca t to b v trc din b m ph hy c th xy ra theo nhiu kiu khc nhau, nh trt phng, trt xoay hoc l. N goi ra, b sng, b bin hoc cc cng trnh gi nc cn c th b xi l, mt n nh di tc ng ca sng hoc hin tng si ng ng, khi cc lp t to b c nhng c tnh c l qu khc bit nhau. 2.2.3. Lc gy trt Lc gy trt ch yu l trng lc, nhng ngoi ra cng cn mt s lc khc hoc yu t khc tham gia gy trt, chng hn nh gc dc, t to mi dc, iu kin kh hu v nc: Trt l xy ra nhng mi dc cao, gc dc ln ph bin hn nhiu so vi nhng mi dc thp, thoi. N c ng vai tr cc k quan trng trong vic gy ra trt l (nc l k th s mt ca n nh mi dc): dng sng v dng chy, nc xi chn dc, lm mt ch da, tng lc gy trt. N c cng c th lm tng lc gy trt bng chnh bn thn trng lng ca n, tc l lp y vo cc l rng, khe nt c trc trong t , khin trng lc tng ln. N c cn gy ra p lc nc l rng, lm gim sc bn khng ct ca t to nn mi dc. Quan trng hn, nhng thay i t ngt (c tng ln gim) ca p lc nc l rng c coi l yu t quyt nh gy ra trt l. N c tng tc vi t , lm t yu dn, gim dn lc khng trt ca chng.

-

2.2.4. Lc khng trt Lc khng trt ch yu l sc bn ca t , bao gm lc dnh kt (kh nng ca cc ht t dnh kt vi nhau) v lc ni ma st (ma st gia bn thn cc ht t vi nhau), tc dng theo chiu ngc li vi lc gy trt. T s gia lc khng trt v lc gy trt c gi l h s an ton (SF). Mi dc c coi l n nh nu SF > 1, ngc li mi dc s mt n nh. Thc t t nht SF cng cn t 1,2-1,3. Ty theo mc quan trng ca mi dc v nhng thit hi c th xy ra m ta phi m bo c c h s an ton ln hn.

37

Tm li, n nh mi dc ph thuc tng ha vo: kiu loi t v sc bn ca chng, hnh thi mi dc (chiu cao, gc dc), iu kin kh hu, lp ph thc vt v thi gian. Tng yu t c th ng vai tr quan trng khc nhau i vi cc lc gy trt v lc khng trt. 2.3. Cc kiu mt n nh mi dc C th phn loi mt s kiu mt n nh mi dc (Bng 3.1) ty theo kiu di chuyn v thnh phn t tham gia qu trnh di chuyn. Thng thng trong mi trng c th xy ra l hoc trt phng theo mt hoc vi b mt gim yu no . Mi trng t ng nht hn, khng c cc b mt gim yu nn thng xy ra trt xoay hoc trt chy. Trong thc t, trt l thng xy ra hn hp, tc l c hai hoc vi kiu di chuyn cng xy ra trong mt hoc c hai mi trng t v . 2.4. Tc ng nhn sinh n trt l Trt l l cc hin tng a cht t nhin, xy ra c ni c ngi ln ni khng c ngi. Th nhng cc hot ng nhn sinh li c tc ng ng k ln cc sn dc. S kt hp gia cc iu kin t nhin bt kh khng (ng t, ma bo ln v.v.) vi cc hot ng nhn sinh bin i a hnh khng lng trc (chng hn o xc lm mt chn mi dc, cht ph, t rng, pht trin th v.v.) c th s gy ra trt l nghim trng.Bng 3.1. Cc kiu mt n nh mi dcKiu di chuyn l Trt Xoay Phng Chm Nhanh Vt liu tham gia qu trnh di chuyn - - Trt xoay trong - Trt phng trong - oi, trn t - St t - Trt xoay trong t - Trt bn - t oi, t trn - t chy - Dng bn (nc chim khong 30%) - Dng bn v.v.

Chy

Hn hp

Kt hp hai hoc nhiu kiu di chuyn

2.5. Gim nh trt l Cng tc gim nh trt l thng bao gm 3 giai on: 1) Xc nh cc khu vc c nguy c trt l; 2) Phng nga; v 3) X l, khc phc hu qu trt l. Trong c 3 giai on ny, iu thit yu l cn hiu bit y cc iu kin, c im a cht khu vc (c th) xy ra trt l. 2.5.1. Xc nh cc khu vc c nguy c trt l Cng vic ny thng do cc nh a cht thc hin, bao gm: 1) Phn tch nh my bay hoc v tinh khoanh nh cc a im tng xy ra trt l, v 2) Kho st thc a ti nhng ni hoc c nguy c xy ra trt l. N hng ni ny thng c a hnh sn dc, g gh, cy ci trn tr hn xung quanh, c nc ngm thm r, cc lp nm ra pha ngoi ng v.v. Sau thnh lp bn tai bin trt l, ch r nhng khu vc c nguy c xy ra trt l nhng mc khc nhau. 2.5.2. Phng nga trt l 38

Vic phng nga tn km v hiu qu hn nhiu so vi vic x l, khc phc hu qu trt l. C rt nhiu phng php phng nga trt l, k c cc bin php cng trnh v phi cng trnh. Trong s cc bin php cng trnh c th k n thot nc ngm, nc mt, gim bt cao v gc dc taluy, trng cy, c, xy tng chn, neo , phun va b tng v.v. nhng iu quan trng l chn la v p dng ng bin php ph hp nht. Hn na, ch nn coi chng nh l nhng bin php b sung, h tr thm cho mi dc sau khi m bo rng mi dc t n (hoc t nht cng tm thi) n nh. iu ny, mt ln na, li i hi phi c hiu bit y v cc c im, iu kin a cht khu vc ang c quan tm. 2.5.3. X l, khc phc hu qu trt l i vi cc sn dc t nhin, c th x l, khc phc hu qu mt s im trt l, chng hn bng bin php thot nc, tho kh nc cho c khi trt, gim p lc nc l rng trong khi trt, ngn chn trt l tip tc xy ra. N hng im trt l xy ra dc cc ng giao thng hoc mt s a im quan trng khc u cn phi c x l v cng vic ny thng rt tn km. N u p dng ng, bin php thot nc mt, nc ngm s rt hiu qu. N hng tic rng bin php ny thng khng c coi trng. Thay vo ngi ta li chn nhng bin php phc tp, tn km hn nhiu m thc t li cho thy hiu qu t c rt thp. Hin ti Vit N am, bin php bo v b sng, b bin, n nh mi dc ph bin nht l cc bin php cng trnh cng, cc b, chng hn nh k bng hc hoc b tng, m hn, tng chn v.v. Chng v ang c p dng hng my thp k nay nhng trt l, xi l vn tip tc xy ra v ngy cng tr nn trm trng hn. Vy nhng nhc im chnh ca chng l g? Xt t gc kinh t, nhng bin php ny rt tn km nh nu trn, v ngn sch N h nc dnh cho nhng cng vic ny khng bao gi . T gc k thut v mi trng, c th nu thm mt s tr ngi nh sau: Cn phi khai thc hoc cc nguyn liu lm b tng t mt ni no , gy ra nhiu tc ng tiu cc ti mi trng. Cc bin php cng trnh cng bo v b sng, b bin khng hp th c bt nng lng ca sng/dng chy. Chnh xc hn, chng khin dng chy/sng ri thm, do cn lm gia tng thm xi l. N goi ra, nhng cng trnh ny thng c tnh cc b, kt thc t ngt, khng chuyn tip t t sang phn b t nhin. Kt qu l chng ch c th li tai bin xi l n mt v tr khc, pha b i din hoc pha h lu. N h th tai ha li cn trm trng hn. Mt s trng hp nh vy tng xy ra nhiu ni thuc cc tnh ven bin Min Trung. Cc bin php cng trnh cng, cc b thng a thm vo h thng sng mt lng ln hc, xi mng, ct, thi ra sng mt lng ln t , khin dng chy b chuyn, y sng nng dn, cui cng lm trm trng thm tai bin l lt v xi l, bi lng. iu ny c bit ng Vit N am khi cc n v thi cng thng t thi trc tip xung sng. Trong mt s trng hp khc, hc c trc tip th xung nc gia cng phn chn b ang mt n nh. i ch, y sng cn c lt thm mt lp khan, khin dng chy b nng hn i. Cui cng, mt khi nhng bin php ny tht bi, dng nc cun i nhng m hn, r , k lt mi v.v., ri chng khp mi ni di y sng.

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Cc cng trnh cng khng tng hp vi nn t mm yu, d xi l bn di. Di sc nng ca cng trnh, nn t bn di b ln hoc b ra tri, lm nt v, ln, dn n ph hy lp cng ph trn. N gi ta th thay cc bn b tng bng cc lp hc kt hp vi vi a k thut nhng vn khng chm dt c cc hin tng ln v xi ngm. Hin tng ny v ang xy ra rt nhiu ni, in hnh l trng hp bin Hi Hu vi c mt on lt khan b v do xi ngm bn di. Cc cng trnh k cng, cc b ch c th gip gim bt xi l b mt. Chng khng c tc dng nu xy ra trt l ln vi mt trt nm su pha di. Tng chn b tng hoc xy l bin php n nh mi dc ph bin nht dc cc tuyn ng giao thng. Tuy nhin phn ln y ch l bin php th ng, ch trt l xy ra. V mt khi trt l xy ra th nhng tng chn ny cng theo nh tng thy kh nhiu ni dc tuyn ng H Ch Minh. Trong mt s ng dng khc, th d nh bo v cc n ct, cc cng trnh k cng hon ton khng ph hp. Vy m chng vn c xy dng mt s ni, chng hn dc mt s on trn tuyn ng ven bin Ph Yn - Bnh nh.

2.6. n nh mi dc bng thc vt Vic s dng thc vt nh mt bin php k thut - sinh hc ci to t, hn ch xi mn v n nh mi dc c bit n t hng trm nm nay v ang tr nn ngy cng ph bin trong mt vi thp k gn y. l v cng ngy ngi ta cng hiu bit v c nhiu thng tin hn v cc loi thc vt c th s dng c trong thit k cng trnh, mt khc cn do tnh hiu qu v thn thin vi mi trng m cch tip cn mm mi ny mang li. Di tc ng ca mt lot yu t trnh by trn, mt mi dc c th tr nn mt n nh do: 1) xi l b mt, v/hoc 2) nhng yu im trong cu trc ca n. Xi l b mt to nn cc rnh xi, dn dn lm mi dc tr nn mt n nh; cn nhng yu im trong cu trc ca mi dc c th dn n trt c khi, c mng. V lu di, xi l b mt cng c th dn n trt l v do vy bo v b mt mi dc cng chnh l mt dng phng nga trt l v n cng ng vai tr quan trng nh cc bin php gia cng cu trc bn trong khc. Trong rt nhiu trng hp, ch cn p dng bin php ny, va hiu qu li va kinh t hn rt nhiu so vi cc bin php gia cng cu trc mi dc khc. Thng thng, mt lp ph thc vt tt, chng hn bng bin php trng c (hoc gieo ht) l hn ch xi l, xi mn, cn mt s loi cy thn g hoc cy bi c b r n su khc c th lm cu trc mi dc bn vng hn. Tuy nhin, nhng mi dc va thi cng xong, lp t mt thng cha c m cht, do rnh xi vn c th pht trin mc d c trng c. Cc loi cy thn g hoc cy bi thng kh mc hoc mc chm trong mi trng bt thun nh vy. C th v th m cc k s thng khng coi trng hiu qu ca lp ph thc vt m mun p dng ngay cc bin php cng trnh. Tm li, trong rt nhiu trng hp, bin php bo v b mt mi dc truyn thng bng cc ging cy, c bn a khng t hiu qu n nh mi dc nh mong mun. 2.6.1. Mt s u nhc im ca bin php bo v mi dc bng thc vt

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u nhc im ca bin php bo v mi dc bng thc vt c th nhn nhn trn c s cc tc ng c ch hoc c hi nh nu Bng 3.2. Bng 3.2. Mt s tc ng vt l ca lp ph thc vt n mi dcTc ng Nhm tc ng c ch Gia cng mi dc bng b r, to neo, nm, b H s din tch, hnh thi v phn b r, sc khng ko ca r; Khong cch trng, ng knh cy v su cho t, gi li cc tng ln, lin kt cc ht t cy bm vo t, chiu dy v th nm ca lp t chu tc ng ca thc vt, sc khng ct ca t Gim m ca t, tng lc ht ca t do r ht m ca t, mc nc ngm, p lc nc l rng nc nui cy v tr li kh quyn thng qua con ng h hp Gim lng nc ma thc t ri xung mi dc do Lng ma thc t tc ng ln mi dc ng li trn thn l ri bay hi Tng sc khng thy lc cc h thng knh mng H s nhm Manning tiu thot nc Nhm tc ng c hi R n xung lm nt t, H s din tch, hnh thi v phn b r Cy to lm mi dc nng thm (c khi c li ty iu Ti trng trung bnh ca thm thc vt ln mi dc kin thc t) Gi bo tc ng ln cy, qua ln mi dc, c khi Vn tc gi thit k, cao trung bnh ca cy trng lm bt gc cy thnh Tng tnh thm ca t Thay i m ca t theo chi su c trng vt l lin quan

Tng kt v kh nng to lp ph thc vt i vi cc khong dc khc nhau c nu Bng 3.3.Bng 3.3. dc v kh nng to lp ph thc vt trn mi dc. dc () 0 - 30 30 - 45 > 45 Lp ph thc vt C D mc, c th p dng k thut trng thng thng Cy thn g/cy bi D mc, c th p dng k thut trng thng thng

Kh dn, c th p dng k thut gieo ht; trn sn ht Kh dn c vi lp t ph Cn p dng k thut c bit Nhn chung ch thc hin c trn cc bc, ng c mi dc

2.6.2. n nh mi dc bng thc vt Vit Nam Cng vi cc bin php cng trnh cng, vic n nh mi dc bng cc gii php mm do hn nh s dng thc vt cng v ang c p dng tuy t ph bin hn nhiu. Trong gim nh xi l b sng, bin php k thut - sinh hc ph bin nht c l l trng tre. gim nh xi l b bin, ngi ta trng bn, c, phi lao, da di v.v. Tuy nhin, nhng bin php ny cn c mt s nhc im sau: Tre mc thnh bi, khng to c hng ro kn. N c l vn c th len qua, v tp trung khong trng gia cc bi, v th sc ph hy cn ln hn, gy xi l nghim trng hn.

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Tre c r chm, nng, ch xung ti su khong 1-1,5m, khng cn bng vi phn thn ngn cao, nng. Do vy cc bi tre thng ch lm b sng nng thm ch khng gp phn n nh b. Vi r chm nng nh vy, nhiu trng hp thy b sng b xi hm ch, to iu kin xy ra trt l quy m ln hn. c, nhng ni chng mc c, c th to nn i m gip gim bt nng lng sng v cc dng chy ven bin, gim nh xi l b bin rt tt. Tuy nhin, c li kh mc v cy con hay b chut n mt ngn v khng tip tc ln c na. Thc t ny tng thy ven bin H Tnh v mt s ni khc. Phi lao t lu v ang c trng trn hng ngn hecta cn ct ven bin Min Trung. Tng t nh vy, da di cng c trng dc cc b sng, sui cng nh ven cc cn ct. Tuy nhin, chng thng ch c tc dng chn gi, tc l hn ch ct bay, ch khng to c hng ro kn v b r cng khng n su gim nh ct chy. mt s ni p ct dc cc dng chy, pha trn trng phi lao, da di nhm hn ch ct chy nhng khng thnh cng. Cc li ct vn tip tc xm ln ng rung, nht l v ma ma. N goi ra, phi lao con khi mi trng nu gp thi tit qu lnh (di 10oC) cng c th b cht, trong khi da di cng c th kh ho khi thi tit qu kh nng v.v.

Rt may l c Vetiver mc rt nhanh, chu c nhng iu kin khc nghit v thi tit v cht t, c th to nn hng ro kn v cng vi b r n su, c th gip n nh, gia cng mi dc trong khong thi gian tng i ngn. y chnh l gii php thay th rt tt cho cc loi cy c bn a nu trn. Tuy nhin, cn ht sc lu l c Vetiver khng phi l mt cng c vn nng, v cn tm hiu k trc khi p dng bin php ny. 3. N NNH MI DC BNG C VETIVER 3.1. Nhng c im c o ca c Vetiver thch hp vi mc ch n nh mi dc N hng c im c o sau y ca c Vetiver c nghin cu, th nghim v pht trin thnh mt bin php k thut - sinh hc n nh mi dc rt hiu qu: Mc d c xp vo loi c, nhng v tc dng n nh t th c Vetiver ging nh cy thn g hoc cy bi pht trin nhanh. Trn mt n v din tch, r c Vetiver cn khe hn r cy thn g. B r s gm hng ngn vn r nhnh n u v rt su, c th xung ti 2-3m ngay trong nm u tin. Kt qu trng mt s ni cho thy, trong vng 12 thng u, r c Vetiver c th n su ti 3,6m trn mi dc t p. B r nh vy gn kt cht cc ht t, ng thi neo cht lp t b ri pha trn vi lp t n nh hn bn di, v vy cy c rt kh b bt gc. B r nh vy cng gip c Vetiver chu hn rt tt (lu rng tt nhin r c s khng n xung qu su so vi mc nc ngm. V th, nhng ni mc nc ngm cao, r c Vetiver c th s khng n su nh nhng ni kh ro hn). R c Vetiver c sc khng ko rt cao, thm ch cn cao hn c mt s loi cy thn g, gip gia cng mi dc rt tt. R c Vetiver c sc khng ct thit k trung bnh khong 75MPa, tc l bng 1/6 sc bn ca thp v c kh nng tng sc khng ct ca t ln ti 39% su 0,5m.

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R c Vetiver c th xuyn qua t b m cht nh t tht, t st cng thng thy min nhit i, tr thnh mt loi neo rt tt cho lp t p hoc t ph. Cc bng c Vetiver c tc dng phn tn u nc mt chy trn, gim bt tc dng chy, qua gim nh ra tri, xi mn. N c chy chm li cn c thm thi gian ngm, tng thm N m cho t. Cc hng c Vetiver, nh cc lp ro cn sinh hc, gi li bn t ti ch, qua gim bt c ca nc mt chy trn. Khi b bn t lp, r mi, chi mi c th mc ra t nhng on thn pha trn v c Vetiver tip tc pht trin. Kt qu l to thnh cc bc thm pha trc cc hng c, dn dn gim dc sn v gim nh xi mn, ra tri. Bn t b gi li ng thi cng cha c ht cy c bn a, dn dn c th t mc c. Chu c nhng bin ng thi tit cc hn, nh hn hn ko di, l lt, ngp ng, c th sinh tn trong khong nhit rt rng t -14oC n 55oC. (Truong et al., 1996). Sau khi nhng iu kin bt li qua i, c Vetiver c kh nng phc hi rt nhanh, c bit l khi c chm bn tt. Chu c nhiu loi t rt xu, nh chua phn, mn, t kim (Le Van Du and Truong, 2003).

C Vetiver ch pht huy tc dng tt khi lin kt vi nhau to thnh hng ro kn. Cc sn dc t nhin, cc mi dc o (taluy ng) v p (, p) u c th n nh bng bin php trng cc hng c Vetiver theo ng ng mc. B r n su gip n nh cu trc mi dc trong khi phn thn bn trn gip phn tn u nc mt chy trn, gim xi l v gi li bn t, to iu kin tt cho cc cy c bn a mc theo (Hnh 3.1). Hengchaovanich (1998) nhn thy rng c Vetiver vn c th mc trn sn dc ti khong 55o. N mc nhanh hn, khng kn t v gip n nh mi dc tt hn nhiu so vi cc ging cy c khc. Mt c tnh na cng lm c Vetiver khc bit hn vi cc ging cy khc, l kh nng xuyn su ca r. Sc mnh v sc sng bN m sinh khin n c th xuyn qua c c t cng ln gc b nt n. Thm ch n cn c th xuyn qua c c lp b tng nha ph ng. Tc gi trn cng cho rng thc t r c Vetiver ging nh cc neo t sng n su ti 2-3m, cng l bin php m cc k s theo trng phi cng thng la chn n nh mi dc (Hnh 3.2). 3.2. Nhng c im c o ca c Vetiver thch hp vi mc ch gim nh thy tai gim nh cc dng thy tai nh l lt, xi l b sng, b bin, xi mn t, bo v p, bo v mi dc v.v., c Vetiver thng c trng thnh hng theo hai hng song song v ct ngang dng chy. N hng c im c o ca c Vetiver cng pht huy tc dng rt tt: Do b r c bit n rt su v rt khe, mt khi mc tt th cc hng c Vetiver c kh nng chng chu c dng nc chy xit. Kinh nghim min Bc Queensland (xtralia) cho thy c Vetiver c th chu c nc sng ma l vi tc trn 3,5m/giy, v vn tr vng mt con knh thot nc min N am Queensland vi tc nc chy ln ti 5m/giy.

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ni nc nng, chy chm, nhng thn c Vetiver rt cng v thng c th to thnh mt hng ro kn lm gim tc dng chy (hay lm tng sc khng thy lc) v chn gi bn t. Chng vn c th ng thng trong dng nc su ti 0,6-0,8m. dng nc su, chy xit, ngn c Vetiver rp xung, va bo v lp t mt ng thi hn ch bt tc dng chy. Khi trng trn cc cng trnh gi nc nh hoc p, cc hng c Vetiver gip lm gim lu tc dng chy, sng leo, sng trn b v do lm gim lng nc chy trn vo khu vc cn bo v. Chng cng gip lm gim c hin tng xi l git li rt thng xy ra khi dng nc hoc sng di ngc tr ra sau khi trn qua , p. V l ging cy mc cc vng t ngp nc, c Vetiver c th sng lu di trong iu kin ngp nc. Kt qu nghin cu ca cc nh khoa hc. Trung Quc chng minh rng c Vetiver c th sng hn hai thng khi b ngp hon ton trong nc trong. Di y xin trnh by chi tit thm v mt s c tnh v tc dng ca c Vetiver.

3.3. Sc khng ct v khng ko ca r c Vetiver Cc th nghim ca Hengchaovanich v N ilaweera (1996) cho thy sc khng ko ca r c Vetiver tng t l nghch vi ng knh r, tc l cc r con c sc khng ct trn n v din tch ln hn cc r to. Sc khng ct ca r c Vetiver thay i trong khong 40-180MPa khi ng knh r thay i trong khong 0,2-2,2mm. Sc khng ct trung bnh thit k l khong 75MPa ng vi ng knh r 0,7-0,8mm, tc l kch thc ph bin nht ca r c Vetiver (gi tr trn tng ng khong 1/6 sc khng ct ca thp). iu ny chng t r c Vetiver khe ngang, hoc thm ch khe hn r mt s loi cy thn g khc tng c coi l c tc dng n nh mi dc (Hnh 3.3 v Bng 3.4). Hengchaovanich v N ilaweera (1996) cng lm mt s th nghim ct phng i vi cc mu t ln r c Vetiver, ly trong phm vi di t rng 50cm xung quanh hng c Vetiver 2 nm tui, cc khm c trong hng cch nhau 15cm. Kt qu cho thy r c Vetiver su 0,25m c th lm tng sc khng ct ca t ti 90%. su 0,5m sc khng ct ca t tng 39% v su 1,0m sc khng ct ca t tng 12,5% (Hnh 3.4).Bng 3.4. Sc khng ko ca r mt s loi thc vtTn khoa hc Salix spp Populus spp Alnus spp Pseudotsuga spp Acer sacharinum Tsuga heterophylia Vaccinum spp Hordeum vulgare Vetiveria zizanioides Tn thng dng Cy liu (Willow) Cy dng (Poplars) Cy tng qun si (Alders) Douglas fir Cy thch (Silver maple) Cy c cn (Western hemlock) Cy vit qut (Huckleberry) La mch (Barley Grass) Ru (Forbs Moss) C Vetiver Sc khng ko (MPa) 9-36 5-38 4-74 19-61 15-30 27 16 15-31 2-20 (2-7kPa) 40-120 (trung bnh 75)

Hn na, do b r dy v u, c Vetiver cn lm tng sc khng ct ca t trn mt n v si g cao hn so vi r cy thn g (6-10 kPa/kg r c Vetiver so vi 3,2-3,7 kPa/kg

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r cy thn g trong mt m3 t (Hnh 3.4). Cc tc gi gii thch rng khi b r c n xung xuyn qua mt trt tim nng ca khi t, cc dch trt dc theo s lm xut hin ng sut ko trong r c; thnh phn ng sut tip tuyn vi mt trt s trc tip gp phn khng trt, trong khi thnh phn ng sut php tuyn vi mt trt s lm tng p sut ln mt trt, qua cng gp phn khng trt. Cheng et al (2003) b sung cc nghin cu ca Hengchaovanich bng cc th nghim i vi r ca cc ging c khc (Bng 3.5). Kt qu cho thy mc d c Vetiver c ng knh r trung bnh nh th hai, sc khng ko ca n ln gp 3 ln so vi cc ging c khc.Bng 3.5. ng knh v sc khng ko ca r mt s ging cGing c C Bc thn Late Juncellus C a Lis (Dallis grass) C ba l (White Clover grass) C Vetiver C rt (Common Centipede grass) C Bahia (Bahia grass) C Manila (Manila grass) C Becmuda (Bermuda grass) ng knh r trung bnh (mm) 0.380.43 0.920.28 0.910.11 0.660.32 0.660.05 0.730.07 0.770.67 0.990.17 Sc khng ko trung bnh (MPa) 24.504.2 19.743.00 24.643.36 85.1031.2 27.301.74 19.233.59 17.552.85 13.452.18

3.4. c tnh thy lc Khi trng thnh hng, c Vetiver s dn dn to thnh mt hng ro kn vi nhng thn c mc thng, chc khe, c th ng vng trong dng nc chy xit ti su 0,6-0,8m. N u b tr cc hng c hp l, chng c th lm gim tc dng chy v phn tn u nc mt chy trn, gip thot nc ma, nc l rt hiu qu. c tnh thy lc c Vetiver di tc ng ca dng nc su c nghin cu i hc Tng hp N am Queensland (xtralia) trong mt s th nghim cho nc chy qua mt knh dn c trng cc hng c Vetiver, nhm mc ch tm ra cc thng s k thut trng c Vetiver gim nh l lt (Hnh 3.5). Kt qu cho thy cc hng c Vetiver lm chm tc dng chy, gim nh ra tri, xi mn t. Kt qu p dng thc t cho thy cc hng c Vetiver bo v rt tt mt cnh ng trng k khi b thit hi v l lt (Dalton et al., 1996). 3.5. p lc nc l rng Lp ph thc vt c tc dng lm tng kh nng nc thm vo t cc mi dc v nhiu ngi lo ngi rng p lc nc l rng nh vy s tng ln, c th dn ti mt n nh mi dc. Tuy nhin, thc t quan st cho thy c Vetiver c nhng tc dng ngc li. Th nht, khi trng thnh hng, c Vetiver gip phn tn u v t t nc mt chy trn, hn ch tp trung nc cc b. Th hai, r c Vetiver ht (cng li u v t t) rt nhiu nc t trong t bc thot tr li vo khng kh thng qua thn l, khin c mt lp t dy 2-3m di chn cc hng c Vetiver lun lun kh ro hn so vi xung quanh. Dalton et al (1996) nghin cu v kh nng cnh tranh N m trong t ca mt s ging hoa mu xtralia. H nhn thy rng trong iu kin t ma, r c Vetiver ht rt nhiu nc trong phm vi di t rng ti 1,5m tnh t chn hng c. N h th kh nng 45

thm nc ca di t s tng ln, gim bt nc mt chy trn v cng vi vic gim thiu mc ra tri, xi mn. Trn cc mi dc trng c Vetiver vi cc hng cch nhau khong 1m theo chiu thng ng, kh nng mt nc theo cch trn cn ln hn na. T gc a k thut, hiu ng ny gip mi dc tr nn n nh hn nhiu. phng trng hp ma qu nhiu vt qu kh nng ht nc ca c Vetiver, c th thit k cc hng c khng hon ton nm ngang, khng song song vi ng ng mc a hnh, m hi xin cho mt vi tiu bt lng nc tha ti mt ch no c sn h thng cng thot nc (Hengchaovanich, 1998). 3.6. Mt s ng dng ch yu ca bng c Vetiver gim nh thin tai, bo v c s h tng Do nhng c im nu trn, c Vetiver rt c tc dng trong cc d n giao thng, thy li, gim nh thin tai, c bit nhng ni t d b trng n, phn r, xi mn nh t kim nng hoc c hm lng natri cao, t chua phn v.v.: n nh mi dc dc cc tuyn ng b, ng st v.v., c bit hiu qu i vi cc ng giao thng nng thn, min ni, ni khng c kinh ph cho vic n nh, bo v taluy v ni cng ng a phng thng tham gia thi cng, xy dng ng; n nh p, gim nh xi l b sng, knh mng, b bin v.v. v bo v chnh cc cng trnh cng nh k b tng, xy, r v.v.; Bo v taluy hoc mi dc ni ca vo v ca ra ca h thng cng dn; Thot nc; Bo v m cu, ni chuyn tip gia kt cu hoc b tng vi nn t; Lm hng ro ngn gi bn t ca vo ca h thng cng dn, thot nc; Lm hng ro hn ch tc dng chy ca ra ca h thng cng dn, thot nc; Trng thnh hng theo ng ng mc pha trn knh mng n nh mi dc, ngn gi bn t khi b ra tri, xi mn xung knh mng; Trng thnh hng theo ng ng mc pha trn cc rnh xi ngn khng cho chng pht trin tip; Trng thnh hng dc theo b , p, pha trn mc nc sng hoc h hn ch xi l, xi mn do sng v; Gim nh nc mt chy trn, ra tri, xi mn, thu gi bn ct v.v.; Trong lm nghip, c Vetiver cng c trng ba rng, taluy ng ven rng nhng ni t dc hn ch xi mn, rnh xi pht trin sau khi thu hoch g v.v.

3.7. Mt s u nhc im ca bng c Vetiver 3.7.1. u im u im chnh ca bng c Vetiver so vi cc bin php cng trnh truyn thng do gi thnh v hiu qu ca n. Th d, p dng VS vo vic n nh, bo v mi dc Trung 46

Quc gip tit kim ti 85-90% chi ph (Xie, 1997; Xia et al., 1999). xtralia, so vi cc bin php cng trnh truyn thng, bng c Vetiver cng gip tit kim ti 64-72% chi ph (Braken and Truong, 2001). Tm li, chi ph ti a cho VS cng ch bng khong 30% so vi cc bin php truyn thng; Cng nh cc bin php k thut - sinh hc khc, bng c Vetiver rt thn thin vi cnh quan, mi trng, rt xanh so vi nhng bin php cng trnh truyn thng dng b tng, , st thp v.v. iu ny c bit quan trng cc th, ni mi trng b xung cp nghim trng do cc hot ng pht trin c s h tng; Chi ph duy tu, bo dng bng c Vetiver rt thp. Khc vi nhng bin php cng trnh khc bt u xung cp t khi a vo s dng, hiu qu ca bin php k thut - sinh hc li tng dn theo thi gian, khi lp ph thc vt dn trng thnh. Bng c Vetiver cn c chm sc, bo v tt trong khong 1-2 nm u, nhng khi mc tt th hu nh khng cn trng coi na. Do vy, bin php ny c bit thch hp vi nhng vng xa xi ho lnh, ni m vic duy tu, bo dng kh trin khai v tn km; c bit c hiu qu ni t cn ci v d b xi mn, ra tri; c bit thch hp vi nhng vng yu cu chi ph nhn cng thp v.v. 3.7.2. Nhc im N hc im chnh ca bng c Vetiver l c Vetiver khng chu c bng rm, nht l giai on u. Di bng rm, mt phn c Vetiver s chm ln; v trong bng rm hon ton, thm ch n b li hn do mt kh nng cnh tranh vi cc ging cy c khc thch nghi vi bng rm. Tuy nhin, nhc im ny mt kha cnh no li rt hu ch, th d trong mt s trng hp, ngi ta cn mt ging cy tin phong, to iu kin n nh v ci thin mi trng cho cc ging khc mc tip, v sau th khng cn n ging cy tin phong na. Cc hng c Vetiver trng theo ng ng mc ch pht huy tc dng khi cy pht trin tt. Do vy, c t ti pht trin tt, cn c mt khong thi gian d phng khong 2-3 thng nu thi tit m p v 3-4 thng nu thi tit lnh. C th khc phc vn ny bng cch trng sm ngay t ma kh. C Vetiver ch thc s pht huy tc dng nu chng to thnh hng ro kn. Do vy, cc khong trng gia cc khm trong hng cn c trng gim kp thi. Vic trng, ti nc v chm sc gp kh khn nhng taluy cao v dc. Cn bo v, khng cho tru b ph hoi trong thi gian u. 3.7.3. Phi hp vi cc bin php khc Bin php trng c Vetiver c th pht huy tc dng tt mt cch c lp hoc kt hp vi nhng bin php truyn thng khc. N h vy c th pht huy trit u im, hn ch ti a nhc im ca bng c Vetiver v tng thm tin cy v an ton. Th d, ti mt on b hoc b sng no , phn di chn , phn ngp nc, c th gia cng bng hoc b tng, cn phn trn th trng c Vetiver. N goi ra, cn c th kt hp trng c Vetiver cc loi cy khc, th d nh tre, th cy xa nay vn thng trng bo v b sng, b . Kinh nghim cho thy rng, nu ch trng

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tre khng thi th khng hiu qu lm v tre c mt s hn ch m c Vetiver c th b khuyt c. 3.8. Phn mm m hnh ha v thit k bng c Vetiver Prati Amati Srl (2006) i hc Tng hp Milan (Italia) xy dng phn mm tnh sc khng ct tng thm ca nhiu loi t trng c Vetiver, rt c ch trong vic xc nh, thit k trng cc hng c Vetiver n nh mi dc, nht l cc mi dc t p. N hn chung, i vi cc loi t v mi dc thng thng, trng c Vetiver c th gip lm tng n nh ln ti 40%. s dng phn mm cn nhp mt s thng s c th v mi dc nh: kiu loi t, gc dc, hm lng nc cc i, lc dnh kt nh nht ca t v.v. Kt qu tnh ton s cho s lng c cn trng trn n v m2, khong cch gia cc hng c v.v. chng hn: 30 cn trng cc hng c cch nhau khong 1,7m; 7-10 khm/m di; 45 cn trng cc hng c cch nhau khong 1m; 7-10 khm/m di.

4. HNG DN CHI TIT N NNH MI DC BNG C VETIVER 4.1. Mt s lu Cn nhn mnh rng bng c Vetiver l mt cng ngh mi, cn nm vng v p dng ng mi t kt qu. N u p dng khng ng s khng t kt qu nh , thm ch nhiu khi cn tht bi. L bin php k thut - sinh hc bo v t, p dng ng bng c Vetiver cn c kin thc c bn v sinh hc, th nhng cng nh cc nguyn l v a k thut, thy lc, thy vn v.v. Khi p dng, c bit l trn quy m va v ln, tt nht l nn c s tham gia ca cc chuyn gia c kinh nghim. Tuy nhin, nhng hiu bit v tham gia v qun l cng ng cng rt quan trng. Do vy, tt nht l trin khai d n vi s t vn ca cc chuyn gia v c Vetiver (kt hp gia chuyn gia nng hc v chuyn gia a k thut) cng vi ngi dn a phng. Mc d theo h thng phn loi thc vt, Vetiver thuc loi c nhng trong thc t, vi b r n su v rng, n li ging nh mt loi cy. Hn na, Vetiver ph hp vi rt nhiu ng dng khc nhau nh nhng c tnh c o nhng cng ht sc khc nhau ca n, chng hn b r su dng n nh mi dc, to hng ro kn v dy phn tn u nc v gi li bn ct, v kh nng chu ng cao i vi cc c cht c dng cho mc ch ci to, x l nhim t v nc v.v. Mt s trng hp khng t kt qu tt ch yu l do p dng khng ng ch khng phi do bn thn cy c Vetiver hoc cng ngh VS. Chng hn trong mt d n ng cao tc Phillipin, bng c Vetiver c p dng bo v cc mi dc, nhng kt qu thu c rt ng tht vng. V sau ngi ta mi bit rng, t k s thit k, cn b k thut theo di thi cng n nhng cng nhn trng v chm sc c u cha h c kinh nghim cng nh cha c hng dn k thut cn thit p dng cng ngh ny trong bo v, n nh mi dc. Kinh nghim mt s nm qua Vit N am cng cho thy, u p dng ng th thnh cng, ngc li s tht bi. Mt s th nghim Ty N guyn t kt qu rt tt, nhng khi trin khai i tr dc tuyn ng H Ch Minh th mt s a im taluy cao, dc, khng

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git cp v.v. vn tip tc xy ra trt l. Do vy, bo m thnh cng, cn lu mt s iu sau y: 4.1.1. Mt s lu v k thut Vic trng c cn c thit k cN n thn v cn c chuyn gia c kinh nghim kim tra; Sau khi trng, c Vetiver cha pht huy tc dng c ngay v mi dc rt c th b trt l trong mt vi thng u. Do vy mi dc d kin bo v bng c Vetiver cn n nh hoc tm thi n nh v cu trc bn trong, t c kh nng trt l t nht l trong my thng u cho n khi c Vetiver hon ton pht huy tc dng ca n; Ch nn trng c Vetiver trn cc mi dc t vi gc dc khng vt qu 45-50o; C Vetiver khng a bng rm, v vy nn trnh trng di cu, di bng cy.

4.1.2. Mt s lu khc khi ra quyt nh, lp k hoch v t chc trng c Vetiver Thi gian: Khi lp k hoch trng c cn lu v ma v khong thi gian cn thit m ging. Chm sc: Khi mi trng, c Vetiver c th cha pht huy tc dng ngay, thm ch mt s c th cht, cn trng dm kp thi. Do vy, khi lp k hoch, d ton cng cn lu vic ny. N hiu hng mc cng vic a phng c th t lm c (chng hn nhn cng, phn bn, cy ging, chm sc, bo dng v.v.). y l u im ca bin php trng c v cng l c hi to thm cng n vic lm cho a phng, m bo cht lng cng nh s bn vng ca cng trnh. Rt nn phi hp cht ch, ti a vi cng ng a phng ngay t khu thit k, quyt nh cc hng mc cn mua sm, k hp ng, u t v bo m cht lng cng trnh. Cc cp c thN m quyn quyt nh cn c tinh thn sn sng v khuyn khch cng ng a phng chp nhn bin php trng c Vetiver thay cho cc gii php truyn thng khc. c bit, khng nn coi nh l mt bin php bo v cc b, c tc dng tc th ng ni xung yu nht. N gc li, nn p dng vi quy m ln t c hiu qu chung mt cch dn dn v lu di mi v sau.

4.2. Thi gian trng c Vetiver Thi gian trng c tnh cht quyt nh i vi thnh cng v mc chi ph ca phng php ny. Trng vo ma kh i hi nhiu cng sc ti nc. Kinh nghim trng c ma kh vng cn ct Min Trung cho thy khi mi trng, mi ngy cn ti 1 hoc 2 ln. N u khng ti, cy c Vetiver khng cht nhng chm pht trin. N u trng trn quy m ln, th d trn nhng taluy sut dc tuyn ng H Ch Minh, kh c th la chn c thi gian trng thch hp nht, do vy cn ti hng ngy bng c gii trong nhng thng u sau khi trng. N u thi tit khng thun, phi ti 3-4 thng, thm ch 5-6 thng sau khi trng c Vetiver mi pht trin n nh, v phi 9-10 thng sau khi trng mi hon ton pht huy tc dng. V vy, cc chuyn gia khuyn co l nn trng khi bt u ma ma, c ngha l phi bt u m ging vo ma xun. 49

Cng c th trng c Vetiver trong v ng - xun, nht l Min Bc. Mc d c ni, c khi nhit xung di 10o nhng c Vetiver vn khng cht, v khi gp ma phn v tit tri m ln l c pht trin ln ngay. Min Trung, ni nhit thng xuyn trn 15o, vic trng c Vetiver trn quy m ln c th bt u t ma xun. 4.3. Vn m c Vetiver Ging tt v cng l yu t quyt nh i vi thnh cng ca d n. Chi tit v m v nhn ging c Vetiver c trnh by Phn 2. N i chung, tr cc d n trng i tr do cc cng ty chuyn nghip thc hin, khng cn lm vn m tp trung quy m ln m ch cn mt s vn m phn tn, mi vn rng vi trm m2, do mt s h nng dn ph trch l . N hng h ny k hp ng v c thanh ton theo s lng c ging m h cung cp theo yu cu ca hp ng. 4.4. Chun b trng c Vetiver i vi cc d n trng c Vetiver trn quy m va v ln, cn c s tham gia ca nhiu ngi dn a phng, c th tin hnh theo cc bc sau:

Bc 1: Chuyn gia kho st hin trng; Bc 2: Trao i vi ngi dn a phng v nhng kh khn, tr ngi v nhng binphp gii quyt;

Bc 3: Gii thiu v cng ngh mi (qua hi tho hoc lp tp hun v.v.); Bc 4: T chc th nghim (lm vn m, k hp ng v.v.); Bc 5: iu hnh, gim st vic thc hin; Bc 6: Trao i v kt qu th nghim (qua hi tho, hi ngh u b v.v.); Bc 7: T chc thc hin trn quy m ln.Trong trng hp d n trng c Vetiver do cc cng ty chuyn nghip thc hin th nn p dng cc bc 1, 4, 5 v 7 nhng s tham gia ca ngi dn a phng vn rt cn thit, t nht l cn nng cao nhn thc cng ng nhm gim thiu nhng hnh ng ph hoi hoc khng tru b dm p. 4.5. Thit k trng c Vetiver 4.5.1. sn dc t nhin, taluy, b ng t p n nh t dc hoc taluy ng, nn b tr trng cc hng c Vetiver nh sau: dc khng nn vt qu 1(H): 1(V), thm ch 1,5:1 hoc thoi hn trn t d b xi ra v/hoc cc khu vc ma nhiu (trong H - chiu ngang, V - chiu ng); N n trng c Vetiver theo ng ng mc vi khong cch gia cc hng (o xui dc) vo khong 1,0-2,0m. ni t d b xi ra, cc hng c nn cch nhau khong 1,0m v tng ln ti 1,5-2,0m nhng ni t n nh hn; Hng u tin nn trng ng mp trn ca taluy i vi tt c taluy cao trn 1,5m; Hng di cng nn trng st chn taluy v dc theo rnh thot nc; 50

Gia cc hng u tin v di cng, khong cch gia cc hng cn li nh nu trn; i vi nhng taluy cao trn 10m, c cch khong 5-8m theo chiu thng ng li nn git cp, nhng ng c rng 1-3m v trng cc hng c Vetiver trn . 4.5.2. ni xi l b sng, b bin v cc cng trnh gi nc mt n nh gim nh l lt, bo v , k, b sng, b bin nn b tr trng c Vetiver nh sau:

dc b hoc , k ti a khng nn qu 1,5 (H): 1 (V), nn 2,5:1 hoc thm ch thoi hn. H thng bin Hi Hu (N am nh) thc t c dc t 3:1 n 4:1; C Vetiver nn trng theo hai hng: n nh b hoc , k, trng c Vetiver theo ng ng mc, song song vi chiu dng chy, vi khong cch gia cc hng (o xui dc) l 0,8-1,0m. Trong mt d n bo v bin mi y Hi Hu (N am nh), khong cch trn ch cn 0,25m; gim tc dng chy, trng cc hng c Vetiver vung gc vi chiu dng chy vi khong cch gia cc hng khong 2,0m i vi t d b xi ra v 4,0m ni t tng i n nh. d n bo v sng Tr Bng (Qung N gi), cc hng c ny thm ch c trng cch nhau ch 1,0m;

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Hng ngang trn cng trng dc theo mp nh dc, hng di cng trng ngang mc nc thp nht (lu l mt s ni mc nc sng c th thay i rt ng k theo ma v do vy c th chn ng thi im nc kit nht trng hng di cng cng thp cng tt. Do mc nc c th ln cao, mt vi hng di cng c th mc chm hn cc hng trn); gia trng cc hng theo ng ng mc vi khong cch nu trn; Khi trng c Vetiver trn cc ngn mn, trong mt khong thi gian no mn ca nc c th tng ln, c th nh hng n s pht trin ca c Vetiver. Theo kinh nghim ca mt d n gim nh thin tai tnh Qung N gi, nn thay c Vetiver bng mt s loi cy chu mn khc nh da cn, ging v.v.; Trong mi trng hp, nh trn nu, c th kt hp bng c Vetiver vi nhng bin php truyn thng khc, th d nh phn chn , k c th lt , b tng hoc vi a k thut, cn na trn th trng c Vetiver.

4.6. Trng c Vetiver o cc rnh su v rng khong 15cm; t cc khm c Vetiver thnh hng, mi khm c 2-3 dnh, khong cch gia cc khm c l 10-12cm ni t d b xi ra n 15cm ni t bnh thng; t trn cc mi dc, sn taluy ng hoc , k t p thng cn ci, do vy nn trng c bng cc ti bu, c bit l i vi cc d n quy m ln, yu cu c pht trin nhanh. Rt c t cc ti bu ra ri t thnh hng trong cc rnh o sn vi khong cch nh trn. Sau t c thng ng v ln cht bng t, nu c th trn ln t vi phn chung v mn th cng tt; t b sng thng mu m, vic ti nc lc u cng khng tn cng sc, do vy c th trng c r trn;

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Khi trng, nn bn phn N PK theo hng vi liu lng 100g/m di. ni t chua phn nn bn thm vi bt khong 100g/m di; Ti nc ngay sau khi trng c; Trong thi gian u, khi c Vetiver cha pht trin tt, c di c th ln t. tr c di nn phun thuc tr c, chng hn dng Altrazin.

4.7. Chm sc c Vetiver 4.7.1. Ti nc Trong 2 tun u sau khi trng, nu thi tit kh cn ti nc hng ngy, 2-4 tun tip theo c th ti cch nht. Sau , mi tun ti 2 ln cho ti khi c mc tt; Khi c trng thnh khng cn ti na. 4.7.2. Trng gim N hng ch c khng mc c hoc b nc ra tri i trong thi gian u sau khi trng th cn trng gim; Tip tc kim tra cho n khi to thnh hng ro kn v khe. 4.7.3. Phng tr c di Cn phng tr c di trong nm u tin, nht l cc loi cy thn leo; C Vetiver rt nhy cm vi thuc tr c Glyphosate, khng nn s dng loi thuc ny tr c ni trng c Vetiver. 4.7.4. Bn phn N i t kh cn, nn bn phn N PK sau khi trng v vo ma ma th hai. 4.7.5. Ct ta Ct ta cng l mt khu quan trng khi p dng bng c Vetiver. C th tin hnh t ct u tin khong 4-5 thng sau khi trng thc cho c pht trin nhiu chi mi. V sau, mi nm c th ct ta 2-3 ln, li khong 15-20cm phn thn ni trn mt t. K thut n gin ny nhm: Gim bt lng l kh c th che khut cc chi non, gip cho chng pht trin tt hn; Lm cho nhng hng c Vetiver xanh ti, thn thin vi mi trng v phng ha hon c th xy ra.

Phn l xanh b ct i c th s dng vo nhiu mc ch, nh lm thc n cho tru b, lm nguyn liu th cng nghip, lp nh v.v. Tuy nhin, khi trng c Vetiver vi mc ch gim nh thin tai, bo v c s h tng th ng nn qun rng mi l mc ch chnh. Chng hn cn bo m rng c cao, rm khi ma ma bo ti. Cn sau ma ma bo th c th ct. Mt thi im ct thch hp na c th l vo khong 3-4 thng trc ma ma bo. 4.7.6. Bo v Khi c Vetiver cn non, tru b rt c th n n, gim p ln hoc cng c th c mt s ngi v thc n nh ph. Khi pht trin tt, c rt cng, khe, khng cn hp dn

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tru b, khng s b ph na. Do vy, nhng ni cn thit, c th lm hng ro bo v c trong my thng u sau khi trng. 5. MT S D N TRNG C VETIVER GIM NH THIN TAI, BO V C S H TNG VIT NAM 5.1. Bo v cc cn ct ven bin Min Trung Di ct ven bin Min Trung rng hn 70.000ha c cc iu kin kh hu, th nhng rt khc nghit. Hin tng ct bay thng xuyn xy ra, cc cn ct di ng dn theo gi. N goi ra, hin tng ct chy cng rt ph bin trong ma ma bo vi hng trm khe, sui, c thng xuyn ln tm thi, chy ngc t pha cc n ct ven bin v pha ni ng. Cc tai bin trn hng nm cun theo mt lng ct rt ln ln dn di ng bng nh hp, che ph nh ca, vn tc, nh hng n i sng ngi dn. Mt s trn l ct ln cn ph hy c s h tng, thm ch gy thit hi v ngi. i dc ven bin Min Trung, hn nhiu ngi nhn thy cc li ct ln ang hng ngy gm dn cc cnh ng m N h nc cng nh tng ngi dn ang phi tm rt nhiu bin php x l nhm gim nh hu qu. T lu, c hn mt chng trnh trng rng trn ct rt ln, vi cc loi cy nh phi lao, bch n, keo, da di v.v. N hng k c khi rm th nhng loi cy trn cng ch hn ch c phn no tai bin ct bay, cn ct chy th cha c bin php no t ra c hiu qu. Thng 2/2002, vi s ti tr ca i s qun H Lan ti Vit N am v h tr k thut ca Elise Pinners v TS. Phm Hng c Phc i hc N ng Lm Thnh ph H Ch Minh, TS. Trn Tn Vn v ng nghip Vin Khoa hc a cht v Khong sn (B Ti nguyn v Mi trng) th nghim n nh cc cn ct ven bin Qung Bnh. a im la chn l mt cn ct thuc lm trng N am, k thn Ph Lu, cng huyn L Thy (Qung Bnh). Hng nm v ma ma, nc t cc cn ct ven bin ngc v pha Ty, to thnh dng sui, gy xi l rt mnh cn ct, lm ny sinh mu thun gia lm trng v ngi dn s ti. Sau khi kho st hin trng, gii thiu v hng dn k thut cho ngi dn a phng, D n tin hnh trng th nghim 3 hng c Vetiver men theo cn ct. Lo ngi v kh nng sinh tn ca c Vetiver trong mi trng bt thun, mt lng phn chung v/hoc t tt c bn thm trc khi lp ct. Thi gian u, cc hng c c ti ngy hai ln, sau gim xung ngy mt ln. Sau 4 thng c mc tt, to nn cc hng ro kn v cn ct tr nn n nh. Lnh o Lm trng rt phn khi vi kt qu t c v quyt nh trng i tr c Vetiver mt s ni khc cng nh bo v mt m cu dc ng Quc l s 1. Kt qu trng i tr cn cho thy, c Vetiver vn pht trin c ngay c khi trng trc tip bng r trn vo ct, khng cn trn thm t tt hoc phn chung. Cy c Vetiver cn tip tc lm ngi dn a phng ngc nhin khi sng qua mt ma ng lnh nht trong vng hn chc nm qua, khi nhit xung di 10oC, lm cht c m la ln cy phi lao non, buc ngi dn a phng phi cy v trng li 2 ln. Sau 2 nm, cc ging cy bn a nh phi lao, da di mc rt tt chnh v tr ca cc hng c Vetiver, lm chng li dn sau khi hon thnh s mnh tin phong, ci to t ca chng. D n chng t rng khi c chm sc tt, c Vetiver c th chu ng tt nhng iu kin bt thun v th nhng v kh hu (Hnh 3.6-12). Theo GS. Henk Jan Verhagen i hc Cng ngh Delft (H Lan), hon ton c th p dng bin php ny hn ch ct bay bng cch trng cc hng c Vetiver chn ngang hng gi cc yn nga gia cc n ct hoc nhng ni c a hnh thp khc, ni vn tc gi c th rt ln. 53

Thng 2/2003, D n t chc hi tho khoa hc v tham quan thc a vi hn 40 i biu t 10 tnh ven bin Min Trung v cc c quan hu quan tham d. Kt qu v kinh nghim ca D n c tip tc trin khai cc huyn Vnh Linh v Triu Phong (Qung Tr, 2003, do Qu World Vision Vietnam ti tr), Qung N gi (D n gim nh thin tai tnh Qung N gi 2003-2006, do AusAid ti tr). 5.2. Bo v , k, gim nh xi l b sng 5.2.1. Bo v , k, gim nh xi l b sng Min Trung Cng trong khun kh D n nu trn, c Vetiver c trng nhm gim nh xi l b sng, bo v cc m tm v bo v nn ng Thnh ph N ng (Hnh 3.13-15). Kt qu l thng 10/2002, Chi cc Phng chng lt bo v Qun l iu Thnh ph cng quyt nh trng i tr nhiu on sng, kt hp vi k hc phn di nc. N goi ra, S Khoa hc Cng ngh Thnh ph cng ti tr tip mt d n th nghim trng c Vetiver bo v taluy dc tuyn ng ln khu ngh mt B N . T kt qu ca D n nu trn, c Vetiver c khuyn co s dng trong mt d n gim nh thin tai khc tnh Qung N gi do Chnh ph xtralia (AusAid) ti tr. Vi s t vn k thut ca TS. Trn Tn Vn, thng 7/2003 KS. V Thanh Thy v ng nghip Trung tm Khuyn nng tnh trng c Vetiver 4 a im th nghim - bo v sng, ngn mn v knh thy li. Mc d trng vo gia ma kh, phi ti nc hng ngy nhng c Vetiver mc tt c 4 a im, v chu ng tt ma l cng nm. Sau thnh cng ca nhng th nghim trn, D n quyt nh trng i tr c Vetiver kt hp vi k lt trn nhiu on khc 3 huyn. D n rt ra mt s bi hc kinh nghim v thay i cht t v thit k nhm ph hp hn vi iu kin a phng. Chng hn, cy ging v cy da nc, chu mn tt hn, c trng hng di cng bo v chn ngn mn, pha trn tip tc trng cc hng c Vetiver. ng thi, c Vetiver cng c ph bin rng ri ti ngi dn a phng h t p dng bo v chnh mnh t ca mnh (Hnh 3.16-19). 5.2.2. Bo v , k, gim nh xi l b sng v bo v cc cm dn c vt l ng bng Sng Cu Long Vi s ti tr ca Qu Donner Foundation v t vn k thut ca GS. Paul Trng, TS. L Vit Dng v ng nghip i hc Tng hp Cn Th th nghim trng c Vetiver gim nh xi l b sng ng bng sng Cu Long. Ma nc y ko di ti 3-5 thng, dng chy rt mnh, chnh lch mc nc so vi ma kh ti 4-5m. B sng, b knh mng c cu to bi t bn st ph sa, rt d b ra tri, xi l. N goi ra, phng tin giao thng ch yu trong vng l ghe my, thuyn my cng sut ln, lin tc to sng lm trm trng thm tai bin xi l. Mc d vy, c Vetiver vn mc tt, gim nh xi l, bo v b sng, b knh mng (Hnh 3.20-21). Cc tnh An Giang v Tin Giang ca ng bng sng Cu Long hng nm thng b l ln, ko di ti 3-4 thng v ngp su ti 6-8m. N h ca ca ngi dn a phng nu khng c xy trn nhng khu vc c bo v s b ngp. V vy, ngi dn thng khng th xy nh kin c v h phi dng li hng nm sau mi ma l. Do vy, vn an c sinh sng lu di tr nn rt bc thit. gii quyt vn ny, chnh quyn a phng ra gii php xy dng cc cm dn c vt l, bng cch chn nhng khu t cao v ly t xung quanh tn cao thm vt trn mc nc l trung bnh hng nm. Tuy nhin b cc cm dn c ny thng b xi l 54

di tc ng ca dng chy l v sng v do vy cn c bo v. Bin php trng c Vetiver t ra rt c hiu qu, cha k v ma kh n cn rt c tc dng trong vic x l nc thi sinh hot t cc cm dn c. Trn c s nhng kt qu , tnh