VTEN DIA LY • VIEN KH&CN VIET NAM HOI DIA LY VIET NAM X„A\ DUTVG HE THONG PHAN LOAI V A B A N D O CANH QUAN TINH DONG THAP PHUC VU MUC D I C H SU DUNG HOP LY TAX NGUYEN VA PHAT TRifeN B E N VUNG Nguye[.]
VTEN DIA LY • VIEN KH&CN VIET NAM HOI DIA LY VIET NAM X„A\ DUTVG H E T H O N G PHAN LOAI V A B A N D O CANH Q U A N TINH DONG THAP PHUC VU M U C D I C H S U DUNG HOP LY TAX N G U Y E N VA PHAT T R i f e N B E N V U N G Nguyen Ho', Hoang Bac^ DAT VAN DE Viec sii' dung hgp ly tai nguyen thien nhien Ianh thd dang la van de thdi sir cua Viet Nam ndi chung va ciia Ddng Thap noi rieng Trong qua tnnh phat trien tinh Ddng Thap cung da dua nhung ke hoach phat trien rieng nham kJiai thac hieu qua cac tai nguyen thien nhien \di sir ddi mdi cac chinh sach kinh te da va dang tao nen nbiSu ebiiyin biln rSt tich cue tat ca cac ITnh vuc ciia ddi sdng xa hdi Cd nhieu tac ddng cd tinh chit tich circ nhu thiic day tang trudng kinh te va chuyen djch ca c§u cay trdng, vat nudi phii hgp hon \ di dieu kien hdi nhap eiia nude ta hien nay, ben canh cung sinh khdng it vAn de bat cap dac biet rat nhieu van de lien quan den viec su dung chua hgp ly ngudn tai nguyen thien nhien van de mdi trudng nhu d nhiem moi trudng nude, suy thoai mdi trudng 6k, sir gia tang cac qua trinh va hien tugng tai bien cac boat ddng san xuSt tir ndng nghiep, cdng nghiep gay Bang phuong phap tiep can dja ly tu nhien tong hgp nhim hilu bilt, nam vung nhung dac diem dieu kien tu nhien, tai nguyen thien nhien tinh Ddng Thap cung nhu cung nhu dl khai thac \ a su' dung hgp ly ngudn tai nguyen cd y nghTa khoa hgc va thuc tiln rk quan trgng De dat dugc muc tieu nay, viec xay dung he thong phan loai va ban canh quan tinh Ddng Thap, cung nhu ti6n hanh phan tich cac dac dilm phan hda chung theo Ianh thd, danh gia canh quan se la ca sd quan trgng nhim dua cac djnh hudng sir dung hgp ly tai ngu>'en, bao ve mdi trudng va phat trien kinh te ben vQng Ianh thd nghien euu la \\k sire co y nghTa va can thiet I CAC NHAN TO THANH TAO CANH QUAN TINH DONG THAP I.l.Vj tridjaly Tinh Ddng Thap trai dgc theo sdng Tiln (thugc he thdng sdng Mekong) theo hudng Tay Bac - Ddng Nam vdi tong dien tich tu nhien la 3.238,05 km2, cd dudng bien gidi vdi cac tinh lan can va nude ban Campuchia la 354,62km Tga dja Ii: tir 10007' den 10058" vT Bac va tir 105012' din 105058' kinh Ddng Tu'can: Phia Bac giap Campuchia (cd dudng bien gidi dai 48,702km) Phia Nam giap tinh VTnh Long (dai 52.83km) Phia Ddng giap tinh Long An (dai 71,74kin) va tinh Tiln Giang (dai 43.37km) Phia Tay giap tinh An Giang (dai 107,82km) va tinh Can Tho (dai 30,16km) Dai hoc Dong Thap "Vien Dia Iv 516 Hdi nghi Khoa hgc Dia ly Todn qud'c lan th&S - Ha Ndi, 201Q VIEN DIA LY - VIEN KH&CN VIET NAM HOI DjA LY VIET NAM Vdi vj tri nam hoan toan viing DBSCL, mot viing ddng bang chau thd tre va rgng Idn, vj tri dja ly se anh hudng rat Idn tdi dac diem tu nhien ciia Ianh thd 1.2 Dja chat Cau tnic dja chat khu vuc khdng may phirc tap, cac tao dja chat Id tren mat dat gdm: Tram tich Pleisto.xen mucin: cd tudi 25.000 - 10.000 nam, vdi nhieu ngudn goc khac Chimg Id nhieu nhat d Tan Hdng, Tam Ndng va mot sd it d Hdng Ngir ma ta quen ggi la phii sa cd cac nai khac bj chim sau: -36 met d Cao Lanh, -29 met d Sa Dec Be day ciia tram tich tir - met Su xuat hien ciia cac Idp laterit tren mat chimg td qua trinh phong boa, boc mdn xay manh me vao cudi giai doan Pleistoxen Tram tich Holoxen: Ngoai trir vimg phii sa cd d phia tay bac ciia tinh, tram tich Holoxen phan bd khap nai Cac tao dja chat Id tren mat dat gdm: Tram tich biln, tram tich bien - gid, tram tich dam lay - bien, tram tich Proluvi - dam lay, tram tich long sdng cd, tram tich sdng - bien, tram tich sdng - dam lay, tram tich sdng Nhu vay, DBSCL ndi chung va Ddng Thap ndi rieng deu dugc tao chii yeu tir cac tram tich Cac boat ddng tram tich anh hudng true tiep den su tao cac dang dja hinh, dat dai, tham thuc vat, va la ca sd quan trgng de hinh canh quan 1.3 Dja hinh Ddng Thap dugc chia 02 vimg dja hinh Idn : - Vimg phia Bac sdng Tien: thugc khu vuc Ddng Thap Mudi (DTM), dja hinh tiro'ng ddi bang phang, cd hudng ddc Tay Bac - Ddng Nam, cao d vimg bien gidi va vimg ven sdng Tien, thap dan ve phia trung tam, tao vimg long mang triing rgng Idn cd dang ddng kit kin, phii sa sdng bien bdi dap da tao viing dat phen rgng Idn Toan vimg cd cao phd bien tir 1,0 - 2,0m; cao nhat > 4,0ni; thap nhat 0,7m Rieng dja ban Hdng Ngu, Tan Hdng cao phd bien tir 2,5 - 4,0m; nai thap nhat la khu virc My An vdi cao 0,7 - 0,9in - Vimg phia Nam sdng Tien: nam kep giii'a sdng Tien va sdng Hau, dja hinh cd dang Idng mang, hudng ddc tir hai ben sdng vao, cao phd bien tir 0.8 - 1.0m: cao nhat la l,5in; thap nhat la 0,5m Dac diem ciia vung la quanh nam cd nude nggt, he thdng sdng rach tu nhien phong phii, tiem nang tudi tieu tu chay kha Idn Tren dja ban tinh cd nhilu nhung khdng dn djnh bdi mdi va sat Id Do cao ciia dja hinh d day khdng dang ke nen cac yeu td tu nhien khu vuc chii yeu chju tac ddng ciia quy luat dja ddi va yeu td hoan luu quyen, anh hudng ciia quy luat dai cao hau nhu bj triet tieu tren lanh thd nghien ciru Nhu vay ciing vdi nen dja chk, dja hinh la phan quan trgng cau tnic dung ciia canh quan tinh Ddng Thap Ck\ triic dja hinh bang phang, thap dan theo hudng tay bac - ddng nam ciing vdi hudng ddng chay cua sdng Mekong, chinh dja hinh vdi cao khac da tao nen sir phan hda ciia canh quan thdng qua qua trinh di chuyen ciia vat chat, cac nguyen to hoa hgc Day cung la mot ca sd de phan chia phu lap canh quan ciia lanh thd nghien ciru 1.4 Khi hau Hdi nghi Klioa hgc Dia ly Todn qud'c lan thve S - Ha Ndi, 2010 517 VTEN DIA LY • VIEN KH&CN 'VIET NAM HOI DIA LY VTET NAM Dong Thap nam vimg nhiet ddi gid miia can xich dao, quanh nam ndng am, lugng mua nam Idn, cac ylu td kill tugng cd su phan hda theo miia rd ret: miia mua tir thang - 1 triing vdi gid miia Tay - Nam, miia klid tii' thang - nam sau triing vdi gio miia Ddng - Bac Chi dd nhiet: Nhiet trung binh nam kha cao (khoang 27''C), dn djnh theo khdng gian va thdi gian Nhin chung khdng cd su khac biet Idn so vdi nhung nai khac d DBSCL, Thang cd nhiet trung binh cao nhat nam, thang 01 thap nhat Nhiet cao nhat d Cao Lanh khoang 37,2°C, thap nhat khoang 15,8 C Chi dm: Do km khdng cao va dn djnh, it bien ddi qua cac nam, am trung binh nam dao ddng tii' 83 - 85%, tai Cao Lanh trung binh la 83%, cao nhit 100%, thap nhat % Miia km tir thang - 11, am trung binh d Cao Lanh tir 81 - 87% Miia khd tir thang 12 - 4, im trung binh d Cao Lanh tir 78 - 82% Chi ndng: Do nam d khu vuc can xich dao nen Ddng Thap cd sd gid nang trung binh nam cao, trung binh qua cac nam dao ddng tir 2300 - 2500 gid/nam, nhien cd sir phan hda theo miia kha cao nen sd gid nang tap trung Idn vao cac thang miia khd Trung binh mdi nam d Cao Lanh cd 2.521 gid nang, binh quan gid/ngay Sd gid nang giam dan theo hudng Ddng Bac - Tay Nam Che gid, bao: Trong nam thjnh hanh hudng gid chinh: gid miia Tay Nam thjnh hanh tir thang den thang 11, thdi tir vjnh Thai Lan hoac vjnh Belgan den mang nhieu hoi nude gay mua va gid miia Ddng Bac thjnh hanh tir thang 12 den thang thdi tir cao ap luc dja hoac cao ap can chi tuyen nen klid va hanh Tdc gid trung binh nam 1,0 - l,5m/s, trung binh Idn nhat 17m/s Che mua: Chi mua lien quan mat thiet den che gid miia Trong nam hinh miia khd am tuo'ng phan sau sac: miia mua tii' thang - 1 triing vdi miia gid miia Tay Nam Miia khd tii' thang - triing vdi miia gid miia Ddng Bac Theo thdi gian, mua d day tap trung vao miia su boat ddng manh me cua gid miia Tay nam Miia mua d day keo dai khoang thang, tii' thang den thang 11 nhung dinh mua thudng roi vao cac thang 8, Lugng mua cac thang miia mua tap trung den khoang 90% tdng lugng mua ca nam Khi hau cd vai trd rat quan trgng sir hinh thanh, phat trien va phan hoa canh quan Khu vuc nghien ciiu cd dac diem hau ndi-chi tuyen, nd da quyet djnh su hinh don vj canh quan Idn nhat la he canh quan nhiet ddi gid miia Nhung dac diem ciia cac yeu td hau cdn anh hudng true tiep den su phan boa cac do'n vj canh quan nhd ban nhu cac kieu canh quan dua vao nhirng dac diem sinh hau cua lanh thd Tinh Ddng Thap vdi sir phan boa rd ret miia mua va miia khd ciia tat ca cac yeu td hau, nhung hau nhu khdng cd su phan hda ve mat khdng gian lanh thd nghien ciru da hinh nen kieu canh quan: rimg kin thudng xanh nhiet ddi mua mua Ddi vdi cac loai canh quan ciing cd sir tham gia ciia yeu td hau gian tilp thdng qua moi quan he tuong hd giua cac nhdm quan xa thuc vat va loai dat Nhu vay, cd the ndi ciing vdi nhan to dja hinh, hau cd vai trd quan trgng quyet djnh su hinh va phan hoa cua canh quan lanh thd nghien ciru 1.5 Thuy van Nam d luu chau thd sdng Mekong, tinh Dong Thap chju anh hudng ciia chi ddng chay sdng Mekong, thuy trieu bien Ddng, che thuy van sdng Tiln, sdng Hau, he thdng sdng Vam Cd va che mua khu virc 518 Hdi nghi Khoa hgc Dia ly Todn qud'c lan thii'S - Hd Ndi, 2010 VIEN DIA LY • VIEN KH&CN VIET NAM ^^ HOI DIA LY VIET NAM Chi thuy van sdng Tien va song Hau chia miia: - Mita kiet: tir thang - hang nam Vao miia kiet, ngoai yeu td thuy trieu cdn phu thugc vao dien biln luu lugng tir thugng ngudn sdng Mekong dd ve Bat dau lii' ihang nguon nude dua ve sdng Tien giam dan, thdi ky kiet nhat hang nam tir trung tuan thang 5, day cung la thdi ky ma sir xam nhap ciia thuy trieu bien Ddng tren sdng Tien va sdng Hau manh nhat Dau thang d thugng ngudn da cd mua nhung luu lugng d sdng Tien va sdng Hau vao cuoi thang mdi rd net Luu lugng nhd nhat tren sdng Tien tai My Thuan tir 800 900mVs, tren sdng Hau tai CSn Tha 700 - SOOmVs - Mua lu: tir thang - 1 hang nam Lii tren sdng Tien, sdng Hau dugc hinh mua d thugng ngudn sdng Mekong va mua khu vuc gay So vdi thugng ngudn, lu d day thudng cham ho'n thang va ket tliiic tre hon thang Liru lugng Idn nhat tren sdng Tien tai My Thuan khoang 16.000 - 18.000mVs, tren sdng Hau tai Can Tha 21 OOOmVs Ciing vdi yeu td hau, thuy van la mot nhu'ng nhan td quan trgng tao, cd vai trd Idn sir van chuyen, phan bd lai vat chat ciia canh quan 1.6 Lop phii tho nhu'ong Theo ket qua dieu tra dat ciia Phan vien Quy hoach va Thiet ke ndng nghiep mien Nam (1997) va ket qua chinh ly ban dd dat (Dai hgc Ndng Lam - 1998), Ddng Thap cd cac loai dat chinh sau: - Nhdm dat cat (Arenosols): Dat cat cd dien tich 66,55ha chiem 0,02% tdng dien tich tu nhien toan tinh va dugc phan bd d huyen Thap Mudi Dat hinh tren nen cat cu (cat gidng), khdng chira vat lieu sinh phen va khdng bj nhiem man - Nhdm dat phii sa (Fluvisols): Dat phii sa cd dien tich 183.939,65ha, chiem 56,85% tdng dien tich tir nhien toan tinh Dat hinh tir tram tich phii sa sdng non tre, khong chira vat lieu sinh phen va khdng bj nhiem man Phan bd dgc theo song rach va cac cii lao cua sdng Tien, sdng Hau, hang nam dugc bdi dap them phii sa mdi - Nhdm dat phen (Thionic Fluvisols): Dat phen cd dien tich 92.380,87ha chiem 28,55% tdng dien tich toan tinh Day la nhdm dat khd khan sir dung cai tao, bj han chi bdi cac dgc chat phen (chua AL^"", Fe"""^, S04"") - Nhdm dat xam: Nhdm dit xam cd dien tich 26.531,41 chiem 8,20% tong dien tich lu nhien toan tinh Dat xam viing hinh tren mau chat phii sa cd (Pleistocene), phan bd chii yeu d ven bien gidi Campuchia Dat la nhan td chi mdi tuong quan tac ddng giira cac nhan td sdng va cac nhan td khdng sdng Dat cung the hien id mdi quan he tac ddng ciia cac nhan td mang tinh dja ddi va phi dja ddi Do dd, su phan boa cac cap canh quan, dat dugc xem nhu la mot yeu td quan trgng, mot chi tieu de xem xet Lanh thd nghien ciiu vdi dac diem phong phii ve loai dat, ciing vdi nhan td sinh vat da tao nhieu loai canh quan khac Day la mot cap don vj canh quan quan trgng viec danh gia tdng hgp dieu kien tu nhien, tai nguyen thien nhien cho cac muc dich thuc tien cu the ciia dja phuang 1.7 Sinh vat Nam khu vuc chju anh hudng ciia nhieu ludng di cu sinh vat, cac tac nhan nhan tac ciing vdi cac dieu kien tu nhien nen Idp phii thuc vat ciia Ddng Thap kha phong phii, gdm: tham thuc vat tu nhien (riing tram, trang cay bui, trang cd); cac tham thuc vat nhan tac (cay hang nam, cay lau nam, rirng trdng, cay an qua, ) Hdi nghi Klioa hgc Dia ly Toan qud'c lan thii'S - Hd Ndi, 2010 ^'^ VIEN DIA LY - VIEN KH&CN VIET NAM HOI DIA LY VTET NAM Trong khu N'UC nghien cu'u vdi su phong phii \ a da dang ve tham thuc y^at da hinh nen cac kilu canh quan khac Ben canh dd sir tac ddng tuong hd giua cac loai dat va cac nhdm quSn xa thuc vat phat sinh da hinh nen cac loai canh quan hit sue da dang, mang dac trung rieng ciia lanh thd 1.8 Mire nhan tac Con ngudi vira la nhan td tao canh quan viia la nhan td tac ddng lam biln doi canh quan Ngay nay, hku bet cac canh quan tu nhien tren lanh thd nghien ciru deu cd su can thiep cua ban tay ngudi d cac miic do, theo ca chieu hudng tich cue va tieu cue, lam thay ddi bd mat canh quan (dieu thi hien rat rd qua dien tich dat chua sir dung toan tinh chi chilm ed 0,02% tdng dien tich tu nhien) Cac tac ddng tich cue nhu boat ddng thiiy Igi, dao kenh din nude, thau chua rira phen; len Hep trdng cay, hinh cac canh quan nhan sinh vdi cac cay trdng thuan Igi cac he sinh thai ndng nghiep, ndng - lam nghiep; hinh cac canh quan dd thj, Qua viec nghien euu dac diem cac nhan td tao canh quan tren day, cd the thay cac nhan td tao ludn cd mdi quan he va tac ddng tuong bd lan mot the thong nhat va tao nen su phan hoa phirc tap ciia canh quan Tren nen chung la he thdng canh quan nhiet ddi am gid miia, su phan hoa ve dja hinh, che nhiet am, sir da dang ve thd nhudng thuc vat da tao nen su phan hda cac dan vj canh quan kliac nhau, phan bd tren rat nhieu klioanh vi, vdi nhiing dac trung rieng ve cau tnic, chuc nang cung nhu klia nang khai thac sii' dung II DAC DILM CANH QUAN TINH DONG THAP II.1 He thong phan loai canh quan va ban canh quan tinh Dong Thap Qua dac diem cac nhan td tao canh quan cd the thay, tren nen chung he thdng canh quan nhiet ddi am gid miia, su phan hda ve dja hinh, sir da dang ve thd nhudng, thuc vat, cac tac ddng nhan tac da gdp phan hinh nen mot he thdng tuang ddi da dang cac canh quan cua khu vuc tinh Ddng Thap Tren co' sd ke thira cac ket qua nghien ciru ly luan va kinh nghiem thuc tien cua cac tac gia va ngoai nude, da de xuat mot he thdng phan loai cho lanh thd gdm cap nhu sau [Bang: 1]: Bdng I He thdng phan loai cdnh quan dp dung cho xay diaig bdn cdnh quan tinh Dong Thap tile 1:100 000 TT Cap phan vj He thong canh quan Phu he canh quan Lop canh quan 520 Cac chi tieu phan chia Vidu Dac trung quy mo ddi tu nhien, - He thong CQ nhiet ddi dugc quy djnh bdi vj tri lanh tho so am gio miia vdi vi tri Mat trdi va cac hoat dong tir quay ciia Trai dat xung quanh no Dac trung djnh lugng cua dieu kien - Phu he thong CQ gio hau dugc quy djnh bdi hoat dong miia khong co miia dong ciia hoan luu quyen mdi lanh vdi hai he thuc vat tuang tac giira dieu kien nhiet - im d tieu bieu dac trung: Ma lai quy mo a ddi, quyet dinh su tdn tai va - Indonesia phat trien ciia quan the thuc vat lien quan den viing sinh thai he thuc vat The hien su tac dong tong hgp ciia cac - Ldp canh quan dong nhan to dia hinh va hau, tir dd tao bang dac trung bdi cac nen cac canh quan khac ca vl qua trinh tich tu vat chat ban chat va dien mao Hdi nghi Klioa hgc Dia ly Toan qud'c Ian thii'S - Hd Ndi, 2010 VIEN DIA LY - VIEN KH&CN VIET NAM Phu lap canh quan Kieu quan canh Loai (nhom loai canh quan) Cac dac trirng trac lugng hinh thai khiion kho lap, the hien can bang vat chat giua cac dac trung trac lugng hinh thai dia hinh, cac dac diem hiui va dac trung ciia quan the thuc vat The hien su tac dong lan giua hai nhan to hau va sinh vat, quyet dinh su tao cac kieu tham thuc vat phat sinh Dac trung bdi moi quan he tuang ho giua cac nhom quan xa thuc vat va loai dat, qu)'et dinh moi can bang vat chat ciia canh quan qua cac dieu kien hau, tho nhuong va nhan tac HOI DIA Lie VIET NAM - Phu lop canh quan ddng bang thap - Kieu canh quan rirng kin thudng xanh nhiet ddi mua miia - Loai canh quan rirng kin thuong xanh tren dat nhiem phen - Loai canh quan liia nude tren dat phii sa xa song Ban dd canh quan Ddng Thap la sir the hien mot each day dii, chi tiet cac dac trung ciia cac tdng the ttr nhien theo he thdng phan loai Tren ban dd canh quan Ddng Thap don vj CO sd dugc the hien la cap loai canh quan Chinh sir tac ddng tuong hd lan giiia cac nhan td tao da tao nen 26 loai canh quan khac thugc mot kieu canh quan la kieu canh quan rimg kin thudng xanh nhiet ddi mua miia nam phu Idp canh quan: phu ldp canh quan ddng bang thap ciia ldp canh quan nhat: ldp canh quan ddng bang Trong tdng sd 26 loai canh quan ciia phu ldp canh quan ddng bang thap cd loai canh quan (sd 1, 2, 3) thugc nhdm dat cat va dat xam khdng bj ngap nude (hoac ngap it) vao miia lu, cac loai canh quan cdn lai deu bj ngap nirdc miia IT; (mot sd canh qu^n chi ngap vao nhfrng nam cd lu Idn) Hdi nghi Klioa hgc Dia ly Todn qud'c lan thii'S - Hd Ndi, 2010 521 HOI D I A LY VIET NAM VIEN DLA LY • VIEN KH&CN VIET NAM Tren ban canh quan nen mau thi hien phu ldp canh quan va sd tii' den 26 the hien cac loai canh quan Trong dd, cac don vj canJi quan lap lai mot each cd quy luat khdng gian, cac canh quan sd 8, 13, 17, 26 chi xuk hien mot \kn, canli quan sd xuat hien vdi sd \kn Idn nhat: 86 lan Cac canh quan cdn lai xuit hien vdi tan suit dao ddng tii' den 72 Ian Bang chu giai bait canh quan tinh Dong Thap CQ R i m g k i n thircmg x a n h nlii^t d o i m u a m i i a Kieu C d n h q u a n P h u ldp Loai CQ Cay a n q u a Lop phii TV CQ Ritng va lau n a m Lu3 c i v liang C a y bill, Sinh va( nSni t r i n g CO thuy sinh kliac Loai d a t ^"~^ ^^^^ Dat cat va dnt x a m [ k l i o n g n g a p nmrc m i i a CTC.X : 11 12 13 lu) Dong bang Dong bang Dat p h i i s a v e n s o n g Pf.Pg Dat p h i i s a x a s o n g P,Pb 10 Dat nhiem phen S 14 15 16 Dat p h e n s a u Sp2 18 19 :o Dnt p h e n n o n g Spl :J :5 thap " • 17 21 22 26 Ghi chu: Cdnh quan nhan sinh dupe the hien bd'ig mot nen mau rieng II.2 Dac diem cau triic canh quan tinh Dong Thap Cac hgp phan ciia canh quan cd quan he tuang hd vdi nhu la mot he thdng va su tuong tac tao cau triic cua canh quan Cau true cua canh quan chinh la su td chirc ben ciia cac ddi tugng va hien tugng pham vi ciia he thdng vat chat phirc tap dd (A.G Ixatsenco, 1965) Cac mdi quan he khdng chi the hien bang su tac ddng qua lai giiia cac yeu td va phan tao canh quan ma nd cdn dugc the hien bang mdi lien he phu thugc giua cac cap canh quan he thdng canh quan Lop cdnh quan Ldp canh quan la cap phan vj cd dac diem hinh thai kien tao rd net, dac trung bdi tinh ddng nhat tuong ddi ciia hai qua trinh Idn chu trinh vat chat: bdc mdn va tich tu, cac khoi dia hinh khac ve vj tri va cao chi phdi Xet tren binli dien chung, khu vuc nghien cun nam trgn ven luu vuc ciia sdng Mekong (sdng Tien va sdng Hau), dugc hinh tren mot dja hinh bang phang nen chi dugc phan chia ldp canh quan ddng bang, cd hudng nghieng Tay Bac - Ddng Nam, tich tu phii sa la qua trinh dja mao chii yeu dien d day, thudng xuyen dugc bdi dap bdi phii sa sdng Mekong va vat lieu dugc dua tir thugng nguon xudng lam tang mau md cho dat Phu lap cdnh quan Phu ldp canh quan dugc chia bdi miic ket hgp ciia hai nhan to dja hinh - hau va bdi cudng cua cac vdng tu^n hoan vat chat - nang lugng Vg dja hinh, mac dii sir chenh lech ve cao dja hinh d Ddng Thap khdng dang ke, nhien sir chenh lech van tao su kliac biet giua cac don vj canh quan, la nhung canh quan bj ngap nude vao miia lii (gdm nhung nai cd cao trung binh tir 2m trd len bj ngap kit it va thdi gian ngap ngan hon vdi nhiing kliu vuc trung, sau ben trong) va canh quan khdng bj ngap nude miia lii (nhung nai cd cao trung binh - 4m, cac gidng, gd cat, cac de tu nhien ven sdng thugc nhdm dat cat va dat xam phan bo chii yeu d kJiu vuc phia Bac, Tay Bac tinh Tuy co sir phan hda ve mat hinh thai dja hinh va phan hda rk nhd vS mat kin' hau nhung 6'\ku 66 la ^22 Hdi nghi Khoa hgc Dia ly Toan qud'c lan thii'S - Hd Ndi, 2010 VIEN DIA LY • VIEN KH&CN VIET NAM HOI DIA LY VIET NAM chua dii de phan chia lanh thd nghien ciru nhieu phu ldp khac Nhin chung toan tinh Dong Thap la mot ddng bang thap, bang phang vdi su chenh lech cao dja hinh khdng dang ke, dd chi cd phu ldp canh quan la: phu ldp canh quan ddng bang thap Trong phu ldp canh quan ddng bang thap van tdn tai mot sd loai canh quan (1, 2, 3) khdng ngap nude miia lu vdi cao trung binh tren 3m (3 - 4in), nhdm dat thugc cac loai canh quan chii yeu la nhdm dat cat va dat xam vdi nhieu dang dja hinh gd, gidng cat tram tich gid bien, tram tich sdng de lai, tham thirc vat chii yeu la rirng thir sinh tren dat cat va nhdm thuc vat nhan tac tren dat cat va dat xam, phan bd tap trung chii yeu d phia bac va tay bac tinh (Hdng Ngu, Tan Hdng, Tam Ndng) Kieu cdnh quan Kieu canh quan dugc phan chia theo dac diem dac trung ciia sinh hau quyet djnh su tao cac tham thirc vat phat sinh khu vuc nghien ciru Dac trung sinh hau ciia lanh thd da chi phdi rat Idn den sir hinh va phat trien ciia canh quan khu vuc, tac ddng den cac qua trinh van ddng va chuyen hda cac canh quan Dieu kien sinh hau dja phuong vdi nhiet trung binh 27 C, am trung binh 82%, lugng mua trung binh 1359mm (tap trung khoang 90% vao miia mua), thdi ky khd doi vdi chu ky sinh trudng ciia thuc vat tir , - thang da tdn tai tren lanh thd nghien euu kieu canh quan: kieu cdnh quan rimg kin thuang xanh nhiet dai mua mua Loai cdnh quan Loai canh quan la dan vj ca sd ciia he thdng phan vi canh quan khu vuc nghien ciru, ma su hinh lien quan chat che vdi quy luat tu nhien mang tinh dja phuang, no the hien qua mdi tuang tac gitia cac dac diem hinh thai nhu ddc, muc chia cat, cac dac diem ddng chay, cac loai dat, cac kieu tham thuc vat Tren ca sd su tuong tac dd, dac biet la su tuang tac ket hgp giua loai nhdm dat vdi loai kieu tham thuc vat phat sinh tren toan lanh thd nghien ciru, da xac djnh dugc 26 don vj canh quan loai canh quan, phan bd d 647 khoanh vi, tan suat lap lai ciia don vj canh quan cao nhk la 86 (canh quan sd 4) va thap nhat la (cac canh quan sd 8, 13, 17, 26) Rieng cac canh quan sd 8, 17, 22, 26 la canh quan mat nude mang dac trimg rieng, cd he sinh thai thuy sinh Nhu vay, dac diem cau true canh quan lanh thd nghien ciru gdm: ldp canh quan ddng bang, kieu canh quan riing kin thudng xanh nhiet ddi mua miia, phu Idp canh quan ddng bang thap va 26 loai canh quan phan bd tren 647 khoanh vi III DAC DIEM C H t r c NANG VA DINH HlTOTSfG STT DUNG CANH QUAN LANH THO NGHIEN ClTU Til' cac dac diSm cau true kha da dang va cd quy luat ciia canh quan dong thdi thdng qua phan tich chirc nang canh quan da cd th8 xac djnh ve ban chat su phii hgp tuong ddi ciia tirng don vj cho viec bd tri phdng hd, san xuat kinh tS ciia tinh gdm: n i l Chiic nang phong ho, bao ve moi truong Cac canh quan cd chirc nang phdng hg va bao ve mdi trudng la cac canh quan phan bd o vimg dau ngudn cua sdng T\kn dja phan Dong Thap va mot so sdng nhd d vimg ven bien gidi Campuchia, dja hinh chii y^i la cac de tu nhien, cac gd ven sdng hoac cac gidng cat cd vdi cao trung binh tren 2,0m, tap trung d phia bac va tay bac ciia tinh (Tan Hdng, Hdng Hdi nghi Klioa hgc Dia ly Todn qud'c lan thii5 - Hd Ndi, 2010 523 VIEN DIA LY • VIEN KH&CN VIET NAM HOI DIA LY VIET NAM Ngu) Tren cac dja hinh phan Idn la tham thuc vat cay trdng hang nam vdi liia nude chiem uu the mot so no'i cd rii'ng trdng gdm cac he sinh thai rirng tram, bach dan va keo la tram Do cd dja hinh tuong ddi cao va d dau ngudn nen cac canh quan cd chirc nang ngan ddng cha\ tran tren be mat va cha\' tran dgc theo cac sdng vao sau ndi ddng, lam giam tac dung cua ddng chay va chain thdi gian ngap lut d cac viing trung ben Cac canh quan chia hai nhdm chuc nang lien quan den dac trung sinh thai canh quan: Nhdm canh quan phan bd tren nhdm dat cat va dat xam vdi he sinh thai rirng trdng (loai canh quan sd 1) Nhom canh quan phan bd tren nhdm dat cat va dat xam, dat phii sa xa sdng, dat phii sa ven sdng vdi he sinh thai cay trdng hang nam, chii yeu la liia nude (cac canh quan sd 3, 5, 11) va he sinh thai cay bui, trang cd (canh quan sd 7) III.2.Chiic nang phuc hdi ty nhien va bao ton La nhung canh quan cd tham thirc vat rimg tu nhien, phan bd d cac khu vuc trung thap, nam sau ndi ddng ciia \iing Dong Thap Mudi Nhdm chuc nang bao gdm cac canh quan sd 9, 14, 18, 23, hau het dang dugc khoanh nudi de phuc hdi rirng, cd chirc nang quan trgng va dac biet dac trirng cho viing Dong Thap Mudi la vira bao ton va tri cac he sinh thai dat ngap nude irng phen viia bao tdn cac ngudn gen ddng thuc \ at quy hiem, ket hgp vdi trdng rirng san xuat de khai thac cd chgn Igc 111.3 Chiic nang khai thac kinh te va phat trien nong nghiep b6n vung Canh quan cd chirc nang khai thac kinh t^ chii y6u cho phat trien ndng nghiep d lanh thd nghien ciiu dugc hinh tren dja hinh bang phang, cd nai trung thap da dugc cai tao Mot sd canh quan DTM, trung thap, cd Idp phen boat ddng va phen tiem tang cao gay khd khan cho phat triln ndng nghiep cd tbi ket hgp md hinh nong lam ket hop hay ndng lam ngu kk hgp, hoac cd bien phap cai tao, canh tac hgp ly nhung can het sire chii y den viec giu- phen va bao ve mdi trudng Cu the nhdm chuc nang gdm: Canh quan lua nude: gdm cac loai canh quan 3, 5, 11, 16, 20, 25, chiem dien tich Idn nhat, phat triln tren nhieu loai dat khac nh§t la tren dat phii sa (so 5, 11), phan bo rgng khap tinh; Canh quan cay trdng hang nam: gdm cac loai sd 6, 12, 21, phat trien tot nhSt tren dat pbii sa ven sdng (so 6) Canh quan sd 13 (cay bui va trang cd tren dat phii sa) neu dugc dau tu cai tao 6k phat triln canh quan cay trdng hang nam se rat tot vi loai canh quan phan bo d sdng, cii lao va ven sdng Tien, sdng Hau; Canh quan cay an qua va cay lau nam khac: gdm cac loai 2, 4, 10, 15, 19, 24, phat triSn tren dat phii sa sdng, phan bd dgc theo cac sdng Idn, d cac dang dja hinh giong de ven sdng, cdn, xen lln vdi cac khu dan cu, tap trung d Chau Thanh, Sa Dec, Lai Vung, Tp Cao Lanh, huyen Cao Lanh ) 111.4 Chuc nang phat trien ngu nghiep ben vung Gdm cac canh quan mat nude, cd thdi gian ngap va lugng nude cung ckp quanh nam, gdm cac canh quan sd 8, 17, 22, 26 Ngoai ra, dac thii cd he thdng sdng, rach chang chjt va cd miia nude ngap keo dai trung binh tir thang trd len nen mdt sd canh quan tiep giap vdi cac sdng, rach (dac biet la cac sdng Idn) cd thS phat triln ngu nghiep tren sdng (nudi ca be), hoac cac canh quan ndng nghiep nhung cd vj tri thuan Igi, gan ngudn nude va thdi gian ngap nude tir thang trd len cd the phat triSn ngu nghiep theo miia theo hinh thirc ndng - ngu kk hgp (cac canh quan so 4, 5, 6) Nhu \ay can cii' vao cac dac diem cau tnic canh quan, chimg ta thay mdi canh quan cd cac chirc nang tu nhien rieng Tuy nhien, hien nhu c^u khai thac phuc 524 Hdi nghi Klioa hgc Dia ly Toan qud'c lan thii'S - Hd Ndi, 2010 VIgN DjA LY • VIEN KH&CN VIET NAM HOI D|A LY VIET NAM VU muc dich phat trien kinh te nen cac chirc nang tu nhien ciia canh quan khu vuc da cd sir thay ddi Tuy vay, de di sau nghien ciru chirc nang ciia mdi canh quan cu thS ddi vdi tirng muc dich sir dung nham dam bao sir ben viing ve mat mdi trudng sinh thai, su dung hgp ly tai nguyen, mang lai hieu qua kinh te cao, can tien hanh danh gia canh quan cho cac muc dich sir dung bang cac phuong phap djnh lugng hoac ban dinh lugng IV KET LUAN Van de tiep can dja ly tu nhien tdng hgp cd the gdp phan lam sang td ban chat ciia tu nhien, lam rd cac quy luat phat sinh, phat trien, cac dac trung phan hda cd quy luat ciia tu nhien de qua dd dua dugc nhiing hudng sii' dung phii hgp phat trien eiia mdi dan vj lanh thd Hudng nghien ciru phan tich, danh gia canh quan cho muc dich sir dung hgp ly lanh thd da dirge van dung nghien ciru d lanh thd tinh Ddng Thap Thdng qua nghien ciru dac diem tu nhien da xay dung dugc mdt he thdng phan loai va ban canh quan tinh Ddng Thap ti le : 100.000 vdi sir phan hda cu the gdm: ldp canh quan, phu Idp canh quan, kieu canh quan va 26 loai canh quan Da xac djnh chirc nang chinh la: chirc nang phdng hd va bao ve mdi trudng; phuc hdi tu nhien va bao tdn; khai thac kinh te va phat trien ndng nghiep ben vung; phat trien ngu nghiep ben vung Nghien ciru xay dunghe thdng phan loai va ban dd canh quan tinh Ddng Thap, phan tich cac dac diem cau tnic, chirc nang va ddng lire canh quan dugc xem nhu la mdt budc dem quan trgng cho cac cdng tac tiep theo ciia viec nghien ciru dja ly tu nhien tdng hgp phuc vu cho muc dich khai thac, phat trien ben vung lanh thd Day cung chinh la ca sd quan trgng, tao tien de de tien tdi danh gia canh quan cho cac muc dich cu the nham dua cac djnh hudng sir dimg hgp ly cac ngudn tai nguyen, phuc vu muc dich bao ve mdi trudng va phat trien kinh te ben vung tinh Ddng Thap TAI LIEU THAM KHAO D.L Armancl Khoa hoc vi cdnh quan NXB KH&KT Ha Ngi, 1983 Nguyin Tiit Ddc Lii, Phen vd man a Ddng Thap Mudi Ky yeu HNKH: Sir dung tai nguyen nude va han chS hau qua lu lut vimg DTM, Tp.HCM, 1995 Trang 60 - 66 Pham Hoiing Hai, Nguyin Thuong Hung, Nguyin Ngoc Khanh Ca sd cdnh quan hoc ciia viec sir dung hap Ii ngudn TNTN, bao ve mdi trudng lanh thd Viet Nam NXB Giao due 1997 Pham Hoang Hiii Nghien cini cdnh quan km vuc sdng Ddng Nai nhdm phat trien kinh te - xd hdi, bao ve mdi trudng Tap chi cac khoa hgc ve Trai Dat, sd 3, nam 2006, Trang 351 - Pham Hoang Hai, Dang Thi Hue Xay dung he thong phan loai cdnh quan tinh Phii Tho ti le : 100.000 Tuyen tap cac bao cao khoa hgc, Vien Khoa hgc va Cdng nghe Viet Nam, Vien Dia Ii, Ha Ndi 2008 Trang 563 - 569 Nguyen Cao HuSn Danh gid cdnh quan theo dip can kinh te sinh thdi NXB DHQG, Ha Ndi, 2005 A.G Ixatsenko, Ca sa cdnh quan hoc vd phan vimg dia ly tu nhien NXB Khoa hgc vaKT thuat Ha Ndi, 1969 Hdi nghi Klioa hgc Dia ly Todn qud'c lan thii'S - Hd Ndi 2010 ^^^ ... phu Idp canh quan: phu ldp canh quan ddng bang thap ciia ldp canh quan nhat: ldp canh quan ddng bang Trong tdng sd 26 loai canh quan ciia phu ldp canh quan ddng bang thap cd loai canh quan (sd 1,... kieu canh quan: kieu cdnh quan rimg kin thuang xanh nhiet dai mua mua Loai cdnh quan Loai canh quan la dan vj ca sd ciia he thdng phan vi canh quan khu vuc nghien ciru, ma su hinh lien quan chat... canh quan loai canh quan, phan bd d 647 khoanh vi, tan suat lap lai ciia don vj canh quan cao nhk la 86 (canh quan sd 4) va thap nhat la (cac canh quan sd 8, 13, 17, 26) Rieng cac canh quan sd