Tgp chiKhoa hgc Trudng Dgi hgc Cdn Tho Phdn A: Khoa hgc Tu nhiin. Cdng nghi vd Mdi tntdng. 35 (2014): 90-103
Tap chl Khoa hoc Tru'dng Dai hoc Can Thtf website: sj.ctu.edu.vn
QUAN L V NGUdN NlTdC MAT CHO HE THONG CANH TAC LUA VUNG VEN BifeN DONG BANG SONG CtJtJ LONG
Hong Minh Hoang', Van Pham Dang Tri' va Nguyen Hidu Trung' Khoa Mdi trudng & Tdi nguyen Thiin nhiin, Trudng Dgi hgc Cdn Tha Thdng lin chung:
Ngdy nhgn: 03/09/2014 Ngdy chdp nhdn: 29/12/2014 TUle:
Surface water resources management for rice farming systems in the coastal areas of the Vietnamese Mekong Delta Tit khoa:
Hi thong canh tdc lua, bien doi khi hgu, tdi nguyen nude mat, vimg ven biin, vd mo hinh Stella
Keywords:
Rice farming systems, climate change, surface water resources, coastal area and Stella—
ABSTRACT
Sea-water intrusion and its negative impacts on rice farming systems in coastal plains of the Vietnamese Mekong Delta are increasing rapidly both in space and lime. The main focus of this study was lo analyze possible solutions to enhance (surface) water storage capacity which could be used to irrigate rice- fields during the water-shortage period (caused by temporal salinity intrusion).
The study was done based on the system-thinking approach and based on the actual characteristics of the study area (local weather, canals system and existing farming systems), and bio-characteristics of crops (growing period and water demand at each Rowing stage). A mathematical model describing interaction between above factors was developed to realise a mutual relationship between demands and availability of water supply during the crop season. The simulation results showed that if the surface water area and depth of internal canals was enhanced (+2.4ha and +0.5m, respectively) in combination with the prediction salinity intrusion, surface water to irrigate 120 ha of rice-field in the lime of salinity intrusion (15 day) could be secured In addition, adjusting the cropping caleruiar and applying water-saving (irrigation) approach (i.e. the alternate wetting and drying technique) also helped to ease negative Impacts of temporal water-shortage due to the rise of salinity from supply water sources.
-^•^-*-~^Tdr dgng tiiu cue cita xdm nhgp man doi vdi he thong canh tdc lua d vimg ven biin Ddng bdng sdng Ciiu Long dang gia tdng nhanh chong cd ve khong gian ldn thdi gian. Mvc lieu chinh eia nghiin cuu ndy la phdn tich cdc gidi phdp khd thi di tra nude nggt nhdm gia tdng ngudn nude nggt phuc vu sdn xudt lua trong thdi gian thieu nude do xdm nhgp man. Nghiin ciiu dugc thuc hiin dva vdo cdch tiip can he Ihdng dva tren ca sd cdc dgc tinh tv nhiin cua vimg nghien ciiu (thdi tiet dia phuang, hi thong kenh muong vd hi thong canh tdc hien co) vd dgc diim sinh hgc cita cdy trong (cdc giai dogn phdt triin vd nhu cdu nude d lung giai dogn phdt trien). Cdc yiu to tren dugc long hgp vd xdy dung thdnh mo hinh todn trong do mo td vd phdn tich cdc moi quan he tdc dgng ldn nhau giUa nhu cdu vd khd ndng cung cdp nude trong sudt miia v|t Kit qud md phong cho thdy niu tdng thim 2.4 ha diin tich mdt nude vdO.5 m chiiu sdu kenh so vdi hiin trgng kit hgp vdi dv bdo xdm nhgp mdn thi co the ddm bdo lugng nude ludi chol20 ha liia trong thdi gian xdm nhgp man 15 ngdy.
Ngodi ra, gidi phdp thay ddi lich ihdi vu vd dp dung phuong phdp tudi tiit kiim cho cdy lua cUng cd thi gidm thiiu dugc dnh hudng cua viic thiiu nude (tgm thdi) do xdm nhgp man gdy ra.
Tgp chi Khoa hgc Trudng Dgi hgc Cdn Tha Phdn A: Khoa hgc Tv nhien. Cdng nghi va Mdi trudng: 35 (2014): 90-103 v i giiia cic ylu td frong tu nhien vdi nhau (vi du:
mdi tiiong quan gifta khi nha khih vdi nhiet dp khdng khf) Id rit khd khin. Do \%y, xac dinh mii tuong quan gifla cic ylu td tbeo m^t tu duy hd thdng dt quin ly tdng hgp r^;udn tdi nguydn nude cd thi hd frg vide ddnh gji t6ng quan thyc trgng quan ly ngudn tdi nguyen nude (Espmosa, 2000;
Pollard and Toit, 2008; Dzwairo et al, 2010) Id vin dd rdt quan frpng ttong bdi cdnh hien nay. Md hinh tu duy he thong (vi du: Stella) da duge flng dyng nhieu frong cdc Imh vye mdi trudng nhim md phdng cae dien bien thyc te ttong ty nhien vi dua ra eic dy bio cdn thiet (Costanza and Ruth, 1998; Leal Neto et al, 2006; Elsawah et al, 2012).
Thdng qua vide xdy dung md hinh dOng, Costanza et al. (1998; 2001) da till hien sy tac dOng qua lgi gifta su phdt ttien cua tdo v i c i hk\, sy kit hgp gifta hd sinh thai vd kinh t l cua rtmg ngip man d Vinh Chesapeake (Brazil). Tilp theo dd, Slraonovie, (2002) da xdy dyng md hinh he thong vl sy bien dpng ngudn tii nguydn nude todn ciu lidn quan den cac ITnh vuc quan ttpng nhu: ndng nghidp, cdng nghidp, ddn so. Tuy nhidn, md hlnb cua Sunonovic xiy dyng de md t i biln ddng nguon nude cho toin cdu chua dd de phin inh chi tilt cho tflng ITnh vuc cy thi ttong md hinh (vi dy: ITnh vyc ndng nghiep). Trdn nln tang dd, Panigrahi et ai (2006; 2011) da nghien cuu thu h?p lai eho ITnh vye ndng n^idp bing viec xdy dyng hd chfla nude eung cap cho ndng nghidp d mien Ddng cda An Dd dya ttdn md hinh hd thdng. Lien quan ddn viec qudn ly ngudn nude bing md hinh h | thdng, Traore and Wang, (2011) di xdy dyng md hinh he tiidng cho hd chfla nude mua ty nhidn phyc vy cho sin xuit ndng nghiep d vdng ban khd cdn d Gaoua vd Fada N'Gourma cua Chiu Phi. 6 Vi^t Nam ndi chung va ddng DBSCL ndi rieng, cd nhilu nghidn cflu ve md hinh he thdng (vi dy: Ngd Ngpc Hung, (2008)) di nghidn curu vd iing dyng vao ITnh vyc mdi trudng va nhieu ITnh vye khdc. Qua dd cho thdy, md hinh hd thdng d i dugc dp dyng rpng rdi vdo ITnh vyc qudn ly tii nguyen nude vi eic ITnh vyc khic.
1 GIOI THIEU
Biln ddi khi hau (BDKH) da va dang lam ttiay ddi cdc didu kidn ty ijiien (lugng mua, nhiet dd v i nude biln ding) va dnh hudng (tidu cyc) den ddi sdng cua con ngudi (Patz et al, 2005). Viet Nam la mpt frong nhung qude gia chiu tdc dpng nghiem frpng cfla hien tupng BDKH, die biet Ii frong ITnh vye ndng nghiep (Yu et al, 2010; GFDRR, 2011;
Bd Tii Nguyen vd Mdi Trudng, 2012). Mdt frong nhftng anh hudng nghiem frong cua BDKH den ITnh vyc ndng nghidp li hien tugng thidu ngudn nude ngpt eung cip cho he thdng canh tic Ifla do man xim nhap d vflng ddng bang ven bien (Wassmann et al, 2004; Seal and Baten, 2012).
Ddng bing sdng Cuu Long (DBSCL) ndm d hg luu sdng Mekong va la vung gdp phdn quan frpng cho an ninh luong thyc quoc gia v i xuit khiu ggo cfla Vidt Nam. Mac dfl vay, ddy cung la vdng dang bi tdc dpng tieu cyc cua BDKH, die biet Id vung ven biln (Vien, 2011; Le Anh Tuin, 2012; UNU- WIDER et al, 2012). BDKH da tdc ddng tieu cyc din hd thdng canh tdc Ida viing ven bidn DBSCL vl vdn de thieu ngudn nude ngpt cung cdp tudi do xdm nhip tnw\ (Wassmann et al, 2004; Nhan et al, 2011; Nguydn Thanh Binh et al, 2012) vi hien trgng xdm nhgp mdn dugc dy bio s2 cang gia tdng ve khdng gian vi thdi gian frong tuong lai (Bp Tii Nguyen vi Mdi Trudng, 2012; UNU-WIDER et al, 2012). Tbeo cdc kjcb bin BDKH eho tiiiy, ttong tuong lai didn bien cfla khi hiu ngiy cang theo hudng bit Igi ddi vdi con ngudi d DBSCL (Trill Quoc Dgt et al, 2012; Van et al, 2012).
Dieu ding quan tim Id xim nhip man ngiy cang ting nhung kha ning thich ung ciia phdn Idn cdng ddng vd cbinh quyen dia phuong khu vyc ven bien DBSCL cdn chua cao. Gidm luu lugng tfl thugng ngudn vi man xim nhip sau vio dit lidn dgc theo kenh rach dugc dy bio se cdn phuc tap ban trong tuong iai (Mekong ARCC, 2013; Vien Klioa hpc Thfly lgi midn Nam, 2013). Do viy, nlu khdng cd bien phip kip thdi dl thich flng vdi hien ttang xim nhgp mgn thi DBSCL se cdn bflng chiu tic hai ning nd do BDKH giy ra ttong tuong lai (Chinh Phfl Viet Nam, 2013).
Vi^c thieu cac cdng cy hien dai (vi dy: md hinh toin, thidt bj quang ttdc mdi trudng tu d0ng) dd h§
ttg cdng tdc ddnh gid tdc dpng cua sy thay ddi cd thd cd ttong tuong lai len san xuat Ida li vin de cung cin dugc quan tdm, ddc bidt la trong vide quin ly ngudn nude tudi. Tuy nhidn, vide xic dinh su tie ddng qua iai gifla hogt dpi^ eon ngudi va mdi trudng (vi du: tic ddng cfla vide sfl dung thudc bao ve thyc vit ngiy cdng nhieu ttong canh tic Ida)
2 PHU'OfNG PHAP NGHIEN CUtJ Phuong phdp nghien ciiu dugc thyc hien g6m cdc ndi dung: (1) xdc djnb khu vyc nghidn cdu; (2) tdng hgp, thu thdp cac sd lieu lien quan ddn vi|c xiy dyng md hinh can bing nude; (3) xdy dung md hinh; (4) hieu chinh va kiem djnb md hinh; (5) xay dyng cdc kich bdn thich flng vdi hi?n frgng thilu nude do xam nb^p man; vi, (6) dinh gii cdc tdc dgng cfla dieu ki?n ty nhien din sy biln ddng
Top chi Khoa hgc Trudng Dgi hgc Cdn Tha Phdn A: Khoa hgc Tv nhiin, Cdng nghi vd Moi irudng: 35 (2014): 90-103 n&Jdn nude tudi cho khu vuc nghien eflu ttong
tttong lai.
^-1 Khn virc nghien cuu
Hioi^n Nga Nam (tinh Sdc Trang) cd ranh ^ d i g j ^ vdi tinb Bge Lieu v i Hgu Giang (Hmh 1), l i viing chuydn sin xuit Ida cd chit lupng cao v i dang bi inh hudng bit I^ do tic ddng cda BDKH.
Hing ndm, Huyen bi anh hudng bcri nude Iu td Hgu Giang va nude min tu BM; Lieu dpc theo tuyln kenh Quan Ld Phyng Hi?p; ttong dd, nude mgn tu Bac Lieu di anb hu&ig nghiem frpng den sin xuit ndng nghidp eua Huy?n. Theo bio cio eua Phdng Tii nguyen v i Mdi trudng bi^en Nga Nam, tinh hinh xam nhgp mgn ngdy cdng frd ndn nghiem
trpng (tang vl khdng gian, thdi gian va ndng dp man) tfl nam 2005 din 2012. Anh hucmg cfla nude man den hd thdng ndng nghiep cda Huyen trong nhftng ndm gdn day cd xu hudng gia tang (nude man den sdm hon, ndng dd cao hon, xdm nhgp sdu hon v i keo ddi hon). Huyen ed h$ thdng gdm 9 cdng ngan man dpc theo tuyln kdnh Phyng Hidp;
tuy nhien, hien nay nude man di xim nhip siu vio ndi ddng vi xim nhgp vdo he thong kenh trfl nude ben frong ndi ddng din den tinh frgng ndng dan khdng the bom nude vdo rudng. Hien trang nude mdn xam nhgp vao he thdng kdnh (kdnh chinh cung nhu npi ddng) gay thieu nude ngpt eung cdp cho cdy Ifla di giy thiet hgi ding ke cho sin xuit ndng n ^ d p cfla Huyen.
Hinh 1: Ban do huy|n NgS Nam 2.2 S6 lieu dau vio, didu kifn ban dau va gia dinh trong md hinh cin bing nurdc
So li?u diu vdo:
Cic du lieu khi tupng thuy van theo ngay (lugng mua, nhiet dp, dp dm, sd gid ning, tdc dp gid, va hoc thoit hoi nude) nam 2011 - 2012 dupe cung cip tu trgm khi tugng thfly van tinh Sdc Tring.
DO li^u md phdng cho tuong lai (lugng mua vi nhidt dp) dugc xudt ra tfl md hinh PRECIS tgi cdc tpa dd nrong flng vdi cac trgm quan trie tiiyc tl va duac cung cdp bdi ttimg tim SEA START (bttp"//www.startor.th/) vdi 2.225 d ludi bao phfl toan bp khu vyc DBSCL, dp phdn giii tuong duong 20 X 20 km. Dft lieu mua xuit ra tu md hmh PRECIS dugc hieu chinh lgi theo phuong p h ^ cdt
(A) va khu vuc nghien cfliiQ
vi hieu chiitirdiing'din cua Hong Miiih Hoang vi Van Phgm Ding Tri, (2013) nhdm cung cip tiidng tin vd lugng mua dy bdo frong tuong Iai d vflng ngbien eflu.
Dft lieu xim nhgp mgn duge eung cip tfl trgm quan trdc cfla buydn Ngd Nam va dft lieu dy bio man (2013) dugc cung cip bdi Vidn Khoa hpc T h ^ lgi miln Nam, (2013).
Didu kidn ban diu: Tdng dien tt'ch rupng d khu vyc nghidn cflu li 120 ba, myc nude rudng ban ddu l i 0 cm vd tdng di|n tich bl m§t cua hd thdng kdnh ndi ddng la 1.2 ha vdi chilu siu hien frgng ndm 2013 Id 1 m dugc thu thap tryc tilp tgi vimg nghien edu.
- Gia dinh: B I mdt dit li bing phing frong qui trinb tinh toin vd xiy dyng md hmh va myc
Tap chiKhoa hgc Trudng Dgi hgc Cdn Tha Phdn A: Khoa hgc Tv nhien, Cong nghi vd Mdi trudng: 35 (2014): 90-103 nude trft ttong kdnh ting den 1.5 m se ty chdy ttin
vdo rupng.
2 J Bac b'nh vl dit, giong liia, lich thdi vu va phmmg phip tudi tgi khu vuc ngbien cuu
Mau dit dugc thu thdp vdo thing 4/2013 vd dugc phin tich (thinh phdn cdp hgt, cic he sd thuy dung (FC), dg im bio hda (SAT), vi dilm heo (WP)) tgi phdng phin tich hda ly vd phi nhidu dit thudc Bd mdn Khoa hpc Dat, Dgi hpc Cin Tho (Bdng 1). Qua cic die tinh cda mdu dat dugc phin ti'ch cho thay, dit tai khu vyc nghien cuu la loai dat set cd khd ndng gift nude cao nen gid tri thim (fryc Bang 1: Thanh phan ciu tao loai d i t tgi khu vye nghi
di) Id khdng ddng kl (Le Anh Tudn, 2005). Theo ket qui nghien cflu cfla Le Van Khoa, (2003) vi Nguyen Minh Phugng et al, (2009), qui frmh canh tdc lua se tgo ra ting dl cdy (tdng nen de), cd tie dung gift nude bl m§t, ngin nude thim xudng ting dudi v i nude td ting dudi thim len ting radt Ngodi ra, loai dat tgi vflng n^idn cuu cd ciing die tinh ly-bda vdi loai dit ttong n ^ d n cim cda Sivapalan and Palmer, (2014) d Kununurra, Tdy Uc, ve viec xdc djnh Iugng nude thim eua dat frdng Ifla vdi gii frj Iugng nude mit di do thim Id 1 mm/ngiy vi duge ip dung cho nghien eflu nay.
LoTTdat % SAT FC % cit % set
0.5 38 0.5 3 1 _ Si > Limax "* Thoat nu(
% thjt 61.5 0 - 1 5 c m
15 - 30cm
59 56
0.58 0.55
0.1 0.1 - Giong Ifla ST5 dugc ngudi din sd dyng tgi
khu vye nghien cflu vdi tbdi gian sinh trudng khoing 115 - 120 ngdy vi dugc chia lim 4 giai dogn phit fridn. Trong nghien cflu niy, mua vy Ddng Xudn (DX) bit diu tfl ngay 1/12/2011 din ngiy 24/3/2012 va mda vu He Thu (HT) bdt diu tii ngdy 12/4/2012 den ngdy 31/7/2012.
Phuang phip tudi dvcqc xay dung trong mo hinh dua vio phmmg phap tudi thyc te cua ngufri dan tgi vflng nghidn cuu. Tgi khu vyc nghien cuu, ngudi din dp dyng phuang phap qudn ly nude cho sdn xuit Ifla li nhu nhau cho 2 vu DX va HT. ^k i p dyng vio mo hinh, phmmg phap tudi ciia ngudi din dugc md phdng lai theo (CT I) vd lugng nude cin tudi dupe md phdng theo cdng thflc (CT 2). Trong qui ttinh canh tic, tdy thudc vio dilu kidn thdi tiet (mua v i hgn ban) ma lupng nude cung cdp tudi vi so lin bom nude thay d6i nhung vin' giftginyc^nudcjdcr.djnb (Ltmin vd Ltmax) qua cdc giai'dogn phit triln cda cdy Ida.
Thdi gian phdt triln cfla cdy lua, thdi gian bom nude vd raye nude qua cdc giai dogn dugc thi hien qua Bing 2:
if = * . i - t p - i f * t . f f < , » £ r o ( C T l ) Trong dd: Kc: He so ciy frdng dya tiieo (TCVN 8641:2011); Kj: hd sd cdng thing vl nude; ETo:
lugng bdc tiiodt hai cfla cay frdng (mm/ngiy); P:
lupng mua (mm/ngiy); vd, S,: myc nude cdn Igi so vdi myc nude ban diu trdn rudng (mm/ngiy). Q moi giai doan phdt friln cua cdy lua, myc nude fren rudng Id khac nhau vdi Lnnax Id myc nude eao nhit va Lnnin Id myc nude nhd nhit va S, thudc khoing gii tri gifta L^w vi Lunu,; ndu S, vugt muc L^aji (do mua) thi ein thoat nude ra vi ngugc Igi, nlu S; nhd ban Hunm thi cdn bom nude vdo (CT).
Si<Ltmu.-* Bom nirdc Bang 2: Lich bom nirdc va muc nude qua cac
giai dogn phdt trien cua cay lua vung d nghidn cuu
Cic giai dogn 0 - 1 5 15-60 60-100 100-115 phit trien ngdy ngay ngay ngay Thdi gian gifta
2 lan bam nude
Khdng bom Muc nude max
3 em 8 cm 8 cm 0 cm
(Lmin) 1 cm 3 cm 3 cm 0 cm
Ngudn: Kel qud dieu tra thuc dja lgi khu vur nghien cuu 2.4 Xiy dung md hinh md phdng biln ddng ngudn nude trong hd thSng canh tic lua
2.4.1 Soc thodt hai nude tham chieu (ETo) Bdc thoit hoi nude tham ehilu (ETo) la lugng nude mdt di qua be mit dit, mit thoang cfla vflng chda nude vd qud trinh thodt hoi qua mat Id, thdn cua ciy do tie ddng ciia nang Iugng mat ttdi, gid, dp im, v i cie ylu td mdi trudng khdc (FAO, 1998). Gid tti ETo dugc xic dinh theo phuang phap Penmen-Monteith (CT 3) do phuong phip nay cho ket qud phfl hgp nhat vd xic dinh nhu ciu nude cfla ciy fr^ng do kdt hgp nhilu mdi c^uan hd cic ylu td khi hdu (Meyer, 1999; Tri^u Anh Ngpc et al, 2006; FAO, 2012).
903 ETft
T^ ChiKhoa hgc Trudng Dgi hgc Cdn Tho Phdn A: Khoa hgc Tv nhiin. Cdng ngh? vd Mdi Irudng: 35 (2014): 90-103 Trong do: EToi B ^ tiioit h o i n u d e (mm
" g s y ) ; Rn: L u d i bdc xa fren b l mat cdy fr^ng (MJm-^ngdy'); G: Thdng lugng nhidt cfla d i t (Him-^ n g a y ' ) ; Tt Nhiet dp tiamg bmh khdng khi tai dp eao 2 m ("C); U2: Tdc dd gid tai 2 m c h i l u c a o so vdi mdt dk (m.s-'); e,: A p s u i t h o i n u d e b i o h d a (kPa); e„: A p s u i t hoi nude thyc t l (kPa); (er- e.): S y t h i l u byt dp lyc bao hda hoi n u d e (kPa); A:
D d n ^ i e n g eua d u d n g quan he g i u a nhiet dd vdi dp s u i t h o i b i o hda tgi nhiet dp t (kPa°C-^); vd, 7:
H i n g sd b i l u nhiet ( k P a ° C ' ) .
2.4.2 Nhu cau nude cho cdy trong (ETJ N h u edu n u d e cho cdy frdng ( E T J l i lupng n u d e mdt di trong qua trinh bdc thodt hai n u d e v i cung l i l u g n g n u d e e i n eung c i p dfl eho cdy trdng ttong q u a trinh phdt frien dugc xdc dinh theo cdng thflc ( C T 4). H e sd Kc ddi vdi c i y lua duac s u dung theo T C V N 864:2011 v l cdng trinh tiifly lgi 1^ thudt tudi tieu n u d e cho cdy luong thyc vd cay t h y c pham; ttong dd, Kc d cac giai doan p h i t triln t d 0 - 15 ngay, 15 - 60 ngdy, 60 - 100 n g i y vd 1 0 0 - 115 n g i y l i n lugt la 1.12, 1.44,1.82 v i 1.63.
ET^=Hr>fEra (CT4)
2.4.3 Tuang Idc giUa nguon nude Irong rugng vd kinh ngi dong
Ddi v d i kenh, l u g n g n u d e vao bao gdm t u lugng m u a , ttgm bom, lugng nude c h i y trdn tfl rugng; l u g n g n u d e ra bao gdm tfl bdc hoi, t h i m , thodt n u d e v a d u g c thd hidn qua p h u o n g ttinh ( C T 5).
rt*i) = I ^ t 4- P -MT^} - ( i t <- B + DO ( C T 5) - Ddi vdi rudng, lugng nude v i o bao gdm tfl lugng m u a , lugng n u d e chdy t r i n tft kenh;
lupng n u d e r a bao gdm tfl bdc thodt hoi cay frdng, t h i m , thodt n u d e vd d u a c till hidn qua p h u o n g frinh ( C T 6).
f f e a J = CRa 4 Cu) - (L -fr ET, + D J ) ( C T 6) - S u t i c dpng giua ngudn nude frong kenh v i ngudn n u d e ttong rudng cfla hd thdng canh tdc lua d u g c minh hpa d (Hinh 2) va d u g c t h i hidn qua p h u o n g frmh ( C T 7). C i e phuong ttmh fren d u g e xdy d y n g t h i n h mdt md hinh he thdng dpng the hi?n mdi quan he c i c t i c dpng ldn nhau theo thdi gian bdng phdn mem he thdng Stella 10.0.
r ^ = i t X i J -t J t C i ) = (/?i + P -I- C^ -I- CQ - ( / i + £ - { - / , + ET^ + D) Trong do: Ri: N u d e vdo kenh t d m u a
(m^/ngay); Ri: N u d e vdo rupng tfl m u a (m'/ngay);
C^ N u d e vdo kdnh t d ru^ng (m^/ngay); O : N u d e v i o rudng td kenh (mVngiy); P: N u d e v i o kenh do bom (m-'/ngiy); / / : L u g n g n u d e m a t d o t h i m cua
(CT7) kdnh (m^/ngdy); / j : L u g n g nude m i t do t h i m cua rudng (m^/ngdy); E: L u g n g nude bdc hoi tfl kdnh (m^/ngiy); ETei L u p n g nude bdc t h o i t hoi (m'/ngay); va, i> = (Di + D2): Tidu n u d e (m^/ngay).
Th(»thai cua caytrmg A.
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trong Kenh m DTi 1.2ha M
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H i n b 2 : S o d o m i n h hpa sur bien d d n g nguon nirdc g i u a r u d n g va k e n h cua h e t h o n g c a n h Cac lua 2.5 HifU c h i n h v i kiem dinh ehinh md hinh vd vy H T dugc sfl dyng cho m y c Cdc y l u to cua cdc bidn frong md hinh d u g c
xdy d y n g n h u nhau cho vy D X va HT; ttong dd, sd lieu cua vy DX d u g e sfl dyng eho m y c dich hi?u
dich kiem djnh md hinh.
P h m m g p h d p hieu c h i n h :
Tgp chi Khoa Im Trudng Dgi hgc Cdn Tho Phdn A: Khoa hgc Tv nhien. Cong nghi vd Mdi trudng: 35 (2014): 90-103 Chgn biin hieu chinh: biln "Trgm bcrm" li
mdt frong cdc biln quan trpng nhit frong md hinh do quylt dinh din lugng nude bom vio vd thdi gian bom nude di kit qua md phdng cfla md hinh phu hgp vdi kit qua thyc tl vl each qudn ]•$ nude cho sdn xuat lua va dugc chpn Idm bien hieu ehinh.
Cic ylu to trong biln "Tram bom" dugc thi hidn qua phuong trinh cin bing nude (CT 8) vd dugc dinh nghTa nhu sau: Lugng nude bom vao (Qp) phy Ihugc vdo tdng lugng nude trdn rudng bao gdm lugng nude sdn cd tren rupng (Q), lugng nude tu mua (Qr) (nlu cd mua) vi lugng nude tfl kdnh
chiy trdn vio mdng (Qk). Trgm bom se tiln hanh bcnn nude ndu tdi^ lugng nude trdn rudng "nhd ban" bode "bing" lupng nude thap nhit dugc quy djnh tai mflc bom nude (Dr*(L + ffo-fa) trong do:
Dr Id diin tich rudng, L Id mice nude rugng ban ddu, Hfmin Id muc nude md tgi do liin hdnh bam nude). Bdn canh dd, biln ndng dd min (Ec) cung quan ttpng ttong vide quy dinh mflc ndng dg mSn khdng dugc phep bam nude Lugng nude bom vdo bdng tdng didn tieh rudng nhin vdi myc nude rupng va ttfl di phin lugng nude sin cd ttdn ru^ng vdi lugng nude vio rudng tu mua (neu cd mua).
Qp = //" Q + Qr + Qk <= DT*iL+H^,„) and Ec<%> then Dr*(L+M^) - (Q+Qr) else 0 (CT 8) Trong do: Qp: Lupng nude bom vdo (m^; Q-
Lugng nude sdn cd ttong ruOng (m'); Qr: Lupng nude vdo rupng tfl mua (m^); Qk: Lugng tfl kenh vdo rudng (m-*); Dr: Dien tich rudng (m-); Ec:
Ndng dp mdn (%o); L: Myc nude luOng ban diu (m); Himin: Myc nude thip nhit quy dinh gidi hgn (dudi) bom nude vio (m); va, Hmua: Myc nude eao nhat quy dinh gidi ban (fren) ngung bom nude (m).
Hi?u chinh biln "Trgm bom":
Birdc 1: Hiiu chinh gid tri Himta: Hidu ehinh gid tti Hunix dd ket qui cfla md hinh phu hgp vdi kdt qui thyc td vd myc nude cao nhit.
Birdc 2: Hieu chinh gid tri Hmda: Sau khi hidu chinh Hunax tien hdnh hipu chinh Pitmm de ket qud cfla md hinh phu hgp vdi kdt qui thyc tl ve myc nude thap nhat
Budc 3: Hieu ehinh Iai vdi budc 1 v i budc 2 den khi kdt qui md phdng myc nude (cao nhdt vd thdp nhit) cfla md hlnb tuong duoi^ vdi gid trj myc nude thyc tl qua cdc giai dogn phat ttidn cfla cay lua. Trong nghidn cflu ndy, khodng chap nhan sai lech myc nude ciia md hinh vi thyc te ttong khodng ±0.5 cm.
2.6 Xiy dyng cdc kfch ban thi'ch flmg Cdc kjcb ban dugc xdy dyng cho ca hai vu DX v i HT nhim dd khic phuc tinh ttgng thilu ngudn nude tudi cho sdn xuit Ida do inh hudng bdi xdm nhip m|in v i thich flng vdi sy biln ddng eua ngudn nude tudi cho tuong lai. Cdc kich bdn dugc xiy dyng cho viing nghidn eflu bao gdm:
Ddnh gia kha ning dy bio man frong viec
quan ly nude cho ciy Ifla vdi gii dinh li ngudi din sd nhan duge thdng tin du bio min tfl ca quan dia phuang, tfl do ehfl ddng bom frfl nude vdo kenh npi dong khi nude min xdm nhgp den.
Tliay ddi lich thdi vu de thich flng vdi tiidi gian min xim nhap. Gidi phip nay dugc ip dung bing each bdt ddu mua vy mdi sau khi kit thdc thdi gian man xdm nhgp.
Ap dyng phuong phdp tudi tidt kidm nude (AWD) hay edn ggi la tudi ngdp-khd xen kd dugc nghidn cuu bdi Vien Ngbien eflu Lua quoc tl (IRRI) phdt triln vd dang dugc flng dyng vdo thyc te tgi mdt sd khu vyc d DBSCL (Tuong, 2003;
2007) dl thay ddi phuang phdp tudi truyin thong.
- D I xudt gidi phip thich flng vdi tinh ttang thilu nude do xdm nhip min bing viec co cdu 1^
h? thdng kdnli muong ndi ddng nhdm tdng khd ning trft nude.
Giim didn tich dit canh tdc Ida dl gidm Iugng nude su dyng.
Md rdng kenh ngLdong^(r^ng,.,siu). ting kha ndng trft nudc.-'^ • -v---' ^.'iasSk i? ?tiii •i-iv...-,;:;
2.7 Binh gia sy tdc dpng cda cie dilu ki^n i\f nhien din kha nang cip nirdc trong tuong lai Vide ddnh gii sy tic ddng cfla eic didu kien ty nhidn ddn khi nang c ^ nude cho sin xudt Ida tai khu vyc nghien cflu frong tuang lai dugc thyc hidn tiidng qua vi?c phdn tich dp nhgy cfla md hinh. Cac biln ttong md hinh dugc chpn dl phdn tich dd nha^
gdm: (I) sy thay ddi Iugng mua; (2) sy thay ddi nhidt dd; vd (3) su thay ddi thdi gian xim nhgp man nhay dupe till hien d Bing 3.
Bang 3: Cdc yeu to phan ti'ch dp nhay cho md hinh c^n bing nude Cic ylu td Thay ddi luyng mua Thay ddi nhidt dp
50%; 75%; 95%
Khdng ddi Khdng ddi
Khdng ddi 50%; 75%; 95%
Khdng ddi
Khdng doi Khdng dk\
20nfiay; 25ngdy; 30ngiy
T^p chi Khoa hgc Trudng Dgi hgc Cdn Tha Phdn A: Khoa hgc Tu nhiin. Cong nghi vd Mdi trudng: 35 (2014): 90-103 G i i tri cfla l u g n g m u a v i nhiet dp gjai dogn
(2015 - 2030) tfl md h m h PRECIS tbeo kieh ban phit tiiii A2 dUgc chpn dd phan tich dd nhgy cho md hinh, tiidng qua dd nhdm dl ddnh gid su biln dgng ngudn nude frong qui trinh sin xuit khi dilu kien thdi tilt thay doi. Day sd Heu dugc s ^ xip theo thfl ty 2 nam lidn tilp nhau vd chpn cdc gid tri cua Percentile 75%, 85% vd 95% cua giai doan md phdng (2015 - 2030), frong dd gii tri mua tfl md binh PRECIS duge bleu chmh lgi tiieo phuang phdp cua Hdng Minh Hoing vd Vin Pham Dang Tri, (2013).
Xdm nhip man dugc du bio sd tdng ldn vl khdng gian l3n thdi gian d cdc cfla sdng trong tuong lai (Van et al, 2012; Vidn Khoa hpc Thuy lpi mien Nam, 2013). Theo nghien cuu cua Le _Sdni, (2006) thi diln biln dd man frdn sdng vflng DBSCL rit phuc tgp, phy thudc vdo ddng chdy
khdng dn dinh cua chl dp frilu giy ra nen chua ddnh gid dugc hien trang xim nhip min d viing nghien cdu. Do viy, gid dinh rdng thdi gian man xdm nhip ttong tuong lai tang len Id 20, 25 vi 30 ngiy so vdi hi?n tai li 15 ngiy nhim de dua ra cac giai p h ^ thich flng vdi hien frgng thieu ngudn nude tudi khi thdi gian xam nhgp man tdng len frong tuong Iai.
3 KET QUA VA THAO LU4.N 3.1 Md hinh cSn bdng nirdc giira ru$ng va kSnh Nhihig yen td lidn quan cd inh hudng den sy bien dpng ngudn nude gifla rudng vd kenh ttong qud frinh sdn xudt Ida tgi vung nghidn eflu duge tdng hgp v i xiy dyng tbinh md hinh he thdng dpng bien ddi theo thdi gian. Md hinh he thdng da the hidn chi tiet mdi quan he cua cdc yeu td vd sy bidn ddng ngudn nude gifla rudng vi hd thdng kdnh ndi ddng (Hinh 3).
Hinh 3: Md hinh can bing nude (ddng) giira 3.2 Hi^u chinh va kilm djnh md hinh a. Hieu chinh mo hinh
Md hinb sau kbi bi^u chinh di cho kit qua md phdng phu hgp vdi tiiyc tl vl myc nude frdn rudng qua cac giai dogn phdt ttien cfla cdy Ida (Hmh 4).
Ket qui md phdng cfla md hinh vl myc nude (myc nude cao nhit vi tiidp nhit) ddi vdi gid ttj Honn vd H ban diu cdn chdnh Ipch ldn so vdi thyc td vi syTbenh l?ch vugt muc gii tri chip nhin (> 0.5
rudng va kdnh ndi ddng dviing nghien curu cm) dugc thi hien qua (Bing 4). Qua cdc budc thyc hien tiieo phuang phap hieu chinh, kit qud hieu ehinh eudi ciing cda md hinh cho ket qui phfl hgp vdi kit qui thyc tl ve myc nude cao nhit yd tiidp nhit (Lmm va Lmax) vd gid frj sai ldch thda dilu kidn chip nhdn (<0.5 em); khi dd, d biln "Tram bam", ket qud gid tti Hnnm = (1-9, 3.9, 4.35, 0 era) vd Hmax = (4.1, 9.4, 10, 0 cm) lin lugt qua cdc giai dogn phit ttiln cua cdy Ida.
Tgp chiKhoa hgc TrudngDgi hgc Cdn Tha Phdn A- Khoa hgc Tvnhiin, Cong nghi vd Moi irudng- 35 (2014)- 90-103 Bdng 4: Ket qua hidu chinb muc nude tren rupng (cm) qua cac giai dogn phit triln ciia ciy lua
Cac giai dogn phat tridn 0 - 1 5 ngay
1 D L^miii J- O * 'mjn
IS - 6» nsay 60 -100 neiy TBLmin TBLmi TB Lnl. T B I « „
100-115nsiy TB Lml. TB Lm., MP
TT Sail£ch
MP TT MP TT Sai lecli H O HCf
0.2 1 0.8
0.95 1 0.05
1.8 3 I J
28.6 3 0.14
1.86 3 1.14
3 3 0
6.6 8 1.4
7.98 8 0.02
1.4 3 1.6
2.8 3 0.2
5.97 8 2.03
7.93 8 0.07
Ghi chu: * Tgi gid trf mgc nuac khdo sal Ihuc li; MP: Md phong, TT: Thve ti; HC: Cdc ldn hiiu chinh; HCf: Hieu ehinh cudi ciing: TB: Trung binh (cm), Lmm. Muc nude thdp nhat. Lmax: Mvc nude eao nhdt
• iVTi,re mroT mii plinng trxtctc hifii chinh
• M v c avtfc th^rc t l Lmin
- M i r r ninrc mn p h n n g sail hifn rhinh M u c u i r d c t h u c t l L u a x
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Hinh 4: Ket qua md phdng ve phmmg phap quin ly nude so vdi thyc t l b. Kiem dinh mo hinh
d vy HT, myc nude frdn rudng biln ddng nhilu hon so vdi vu DX; tuy vay, kit qud myc nude rupng md phdng (cao nhit vd thip nhit) qua cdc giai doan phit friln cua cay Ifla vdn phfl hgp so vdi
thyc tl (Hinh 5). Su biln dOng vl myc nude trong vy HT la do dnh hudng bdi lugng mua vi diy cung li ydu td lam gidm sd Idn bom nude so vdi vy DX.
Qua do cho thiy, md hinh cho kit qud md phdng phd hgp vdi kit qui thyc tl dja phuong ve cdch qudn ly ngudn nude cho sdn xuit Ifla.
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12 f 10
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^OP chi Khoa hgc Trudng Dgi hgc Cdn Iha Phdn A: Khoa hgc Tv nhien. Cdng nghe vd Mdi Irudng: 35 (2014): 90-103
^ 3 J xSy dung cdc kich ban thich ung vdi hien trang thilu nude
j.i.7 Khd ndng du bdo man trong qudn ly nguon nude cho nong nghiip
Trong thdi gian xdm nhip man, tdng nhu ciu nude cho cdy ifla Id 120.000 m^ ttong khi do tdng lirpng nude cd kha ndng cung cdp cho eay lua (bao gom lugng nude frd frong kdnh va lugng nude sin CO tten rudng) ttong giai doan niy li khoing 18^000 m^ (Hinh 6). Vdi lugng nude hidn tgi cbi ed thd cung cap dugc khodng 2 ngiy cho cdy lua frong
thdi gian xara nhgp man. Tuy nhidn, vide dy bdo man cd thd gidp ndng dan ehfl ddng bom nude trfl vd frdnh bom nude man vdo kenh ndi ddng vi do vdy Idm ting lugng nude cung eip (bao gdm lugng nude tfl rugng va kdnh) cho nhu cdu tudi len khodng 64.000m^ (Hinh 6) cho nhu cdu nude cfla ciy Ifla. Ket qui cda md hinh cho thiy, du bdo xdm nhgp mdn cd kha nang Idm gidm thieu thdi gian thidu nude nhung khdng the cung cap dfl nude cho Ifla li do dien tich trfl nude cfla he thdng kenh ndi ddng ehua dfl Idn vd do thdi gian xam nhap min keo ddi.
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Hinh 6: Tdng nhu cau nuo'c vi lugng nude cd kha nang cung cap khi cd dy bdo man 3.3.2 Thay doi lich canh tdc
Giii phdp tiiay d6i Ijch canh tie cd thi frdnh dugc hidn trang tiiilu nude tudi eho ciy Ifla do xim nhip mgn frong didu kidn hien tgi d viing nghien cflu (Hinh 7). Tuy nhien, vide thay ddi Ijch canh tie sd tao ra mpt khoang thdi gian ddi gida 2 vy; do vay, ndng ddn ed till tan dyng khodng thdi
gian ndy de trdng nhung logi ciy hoa mdu ngdn ngiy. Bdn cgnh do, giii phdp thay ddi lich canli tdc se gap rui ro cho vy HT do gip dieu kidn thdi tidt bit lgi (lugng mua eao), die bidt Id d giai dogn cudi vy, se dnh hudng den qui trinh phit fridn cfla ciy Ifla, ning suit vi dnh hudng den qud trinh thu hogch.
—Nirdc trd" t r o o g r a ^ D g —N'dngSd m^n
Hinh 7: Giai phap thay ddi Ijch thdi vu tranh hi|n trang s i m nhip min 3 3 3 Ap dung phuang phdp tudi tiit kiim nude
Phuong phdp tudi tiet kiem nude cd the tidt kidm dugc lugng nude vi so lin bom nude so vdi phuang phip W<*i truyen tiidng. Phuang phdp ttrdi tilt kiem nude cd the tilt kiem dugc lugng nude
khoang 200.000m^ vd gidm duge 4 lin bom nude so vdi phuang phip tudi cfla dja phuang (Hinh 8).
Ket qui ndy cd y nghia quan frpng frong vide keo dii thdi gian tudi nude va tidt kiem dugc lugng nude tudi cho ciy Ida ttong thdi gian xim nhip mdn.
Tap chiKhoa hgc Trudng Dgi hgc Cdn Tho Phdn A: Khoa hgc Tv nhiin. Cong nghi vd Mdi trudng: 35 (2014): 90-103
I 1,000
Tong llrgrng Diro'c 1,001
• - - - S6 U B b o u t B i i ^
8 0 2
Phinmg pfaip tirdl iJ|a phirong Pbinmgphip tiT«ltigtkl^iii
Hinh 8: So sinh vl tong lugng nude va so lan bom nude cua phuong phip tudi tilt Idem nude vdi phuang phip tudi d vung nghidn cuu trong mua vu BX
vdi gia tri ban dau. Trong lya chgn niy, tdng nhu eiu nude cho cay Ida la 90.000 m^ v i tdng lugng nude cd the eung cap (bao gdm Iugng nude frdn 3.3.4 Gidi phdp tdng diin lich kinh trii ngi
ding kit hgp vdi du bdo xdm nhgp mgn Vide dy bio xim nhap man tuy khdng giii quydt dugc hien frang xdm nhgp mdn nhung lim giam tiiilu dnh hudng cda hien frgng thilu nude do xim nhgp mdn vi giup ngudi dan chfl dpng bom nude trfl frong rudng vi frdnh viec bom nude min vdo rudng. Vi vdy, ket hgp gifla vide dy bao xim nhip man vdi cic giii phip khic sd cho hieu qua cao frong vin dd dam bdo ngudn nude tudi cho ndng nghi?p bj dnh hudng bdi xam nhgp mdn. Mdt s6 gidi phip kit hgp ting dien tich kdnh trfl nude vd du bio xim nhip man tai vimg nghien cflu cho ket qud nhu sau:
a. Gii? hiin trgng diin tich canh tdc lua vd tdng dien tich kenh ngi dong
Trong didu kidn hidn tgi, khi ting chieu sau kenh them 0.5 m vd tdng didn tieh bd mit kdnh thdm 2.4 ha kit hpp vdi dy bao man thi lugng nude trfl cd khi nine cung eip dfl cho nhu ciu nude cua i Ecdyilflatbab gom lugng nude frdn rudng va lugng nude trfl trong kdnh) frong thdi gian min xam nhip 15 ngdy. Khi do, tdng lugng nude cd khd nang cung cdp la khodng 120.000 m^ tuong duong vdi tdng nhu cdu lugng nude ttong giai dogn niy la 120.000 m^.Vdi gii fri niy, lupng nude trfl cd thi cung cip nude cho toin bd didn tich Ifla (120ha) frong tbdi gian xam nhap man 15 ngiy.
h. Kit hgp viic gidm dien tich canh idc lua vd Idng diin tich kinh
Ndu giim dien ti'ch canh tic lua sd ddn den giim lugng nude cung cip cho nhu ciu nude cua ciy Ifla va khi dd gidm dugc didn tich kdnh phdi md rgng. Do v^y, nlu gidm di 25% didn tieh tr^ng Ifla hidn tai tiii di^n tieh bl mat kdnh ein tdng thera li 1.5ha va chilu siu kenh cin ting thdm 0.5 m so
rupng vd lupng nude trfl frong kdnh) sau khi md rdng kdnh Ii khoing 90.000 m^. Vdi gid frj tren, tdng Iugng nude frfl cd thi cung cip nude tudi cho 75% didn tich Ida frong thdi gian xim nhip min 15 ngdy.
Neu gidm 50% didn tieh frdng Ida hi^n tgi thi di?n tieb be mat kenh cin tang len la 0.8 ha vi ehidu siu kdnh ting them Id 0.5 m so vdi gii tri ban diu. Trong lya chgn nay, t6ng lugng nude cd thi cung cip tudi (bao gdm lugng nude trdn ru^ng vd lugng nude trd ttong kdnh) la khoang 64.000 m^
tuong duong vdi tdng nhu cdu nude cho cdy Ifla li khoing 61.000 m^. Vdi gid tti frdn, t6ng lupng nude trfl cd the cung cap nude tudi cho 50% di^n tich lua ttong thdi gian xim nhip man 15 ngdy.
3.4 Biln dong ngudn nude tirdl trong tuung Iai 3.4.1 Biin dgng do su thay doi lugng mua Trong tuong Iai, lugng mua cd xu hudng ting cao hon so vdi hidn tai va anh hudng den ngudn nude tudi eho cay Ifla. Lupng mua tdng cao trong tuang lai se lam gidm lugng nude tudi v i tilt ki?m dugc ehi phi bom nude cho ndng din. Kit qud md phdng cho thiy, lugng mua ting frong tuong lai ed till dfl Iugng nude eung cip tudi cho nhu ciu nude cua eay Ifla frong vu HT (bi dnh hudng bdi xam nhap man) (Hlnb 9).Error! Reference source not found. Tuy nhien, vio miia mua eic ylu t6 bit lgi vl thdi tiet cd thd gay ra nhu: mua kem theo gid ldn, nhiet dp xudng thip thdi gian chieu sang ttong ngiy gidm, ngip ung,... cic yeu td niy cd thi cd tic dpng gay dd ngi, dich benh inh hudng din ndng suit Ida (Yoshida, 1981; Nguydn Bio Vd, 2009).
TQP chi Khoa hgc Trudng Dgi hgc Cdn Tha Phdn A: Khoa hgc Tv nhien. Cong nghi vd Mdi tnrdng: 35 (2014): 90-103
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Hiuh 9: Anh hirdng ciia SIJT thay dot lirgrng mua den ngudn nude tudi cho tuong lai giai dogn (2014 - 2030) nhu ciu su dung nude cua ciy ttdng v i lam tang lugng nude cung cip. Nhiet dp tang ttong tuong lai lim tang nhu can su dung nude cda ciy Ida ciing nhu tang lupng nude bdc hoi ddn din lugng nude bom va so ldn bom cao hon so vdi hifn tgi (ffinh 10) die bidt la vio mua khd trong vu DX.
Vin dd nay se anh hudng Idn din tinh frgng thilu byt ngudn nude cung cdp tudi cho ndng nghidp frong tuong lai khi ban ban keo ddi vd xim nhip man ngay cdng tang cao. _ _ _ _ _ ^ ^ 3.4.2 Biin dgng do su thay doi nhiet do
Khd ndng cung cip nude tudi eho sin xudt Ida d vung ngbien cflu biln ddng kbdng ding kl khi nhiet dd thay ddi frong tuong lai. Theo md binb dy bdo, nhidt dd tnmg binh ttong tuong lai eao ban so vdi hien tgi v i din din ting nhu ciu nude sfl dyng cho cdy Ida (ETc). Kit qud ndy phu hgp vdi nghidn cihi cua Shrivastava et al (2012) va Vuong Tuin Huy et al (2013) l i khi nhi?t dp ting sd lam tang
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Hinh 10: Anh hudng cua sy thay doi ciia nhiet dp den ngudn nude tuoi cho tuong lai giai dogn (2014 - 2030) ndng nghiep ngiy cang trd ndn nghidm frpng, die biet Id dnh hudng den vy HT (Hinh 11). Do v|y, giii phip md rdng kdnh hay thay ddi Ijch thdi vy cin sdm thyc hien dl thieh ung vdi thyc frang xim 3.4.3 Biin dgng do sir thay doi thdi gian xdm
igp man
Xam nhgp m|n ngiy cdng tdng frong tuang lai din din thdi gian thilu nude ngdy cdng kdo dai ddn
din vide dim bdo ngudn nude cung cdp tudi eho nhap man frong qua trinb sdn xuat ndng nghiep.
TlidlglaBDitilODgi:^- - Tktfl g i u mfn 25 agjly - Tbiri giifl rafii 30 ngi)-
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Hinb 11: Anh hudng cua sy thay ddi thdi gian xam nhgp man den bien dpng nguon nude tudi 4 K^TLU^N
Trong tuong lai, hgn hdn k^o dai cd the inh hudng din sy phit tridn cfla eay Ida. Sy thay ddi
bit thudng vd lugng mua va thdi gian xam nhip man frong tuang Im se inh hudng ding kl din ngudn nude cung cap eho sin xudt Ifla cfla ngudi ddn vung ven bidn. Viec md rdng kenh npi ddng cd
Tgp chi Khoa hgc Trudng Dgi hgc Cdn Tha Phdn A: Khoa hgc Tv nhiin, Cong nghi vd Mm Irudng: 35 (2014): 90-103 till khic phyc tiiuc frgng thieu nude cung cap tudi
cho sin xuit Ida ttong tiidi gian xam nhj^ man.
Viec tdng them 2.4 ha di?n tich mat nude vi 0.5 m ehilu sdu kdnh so vdi hidn frang kit hgp vdi dy bio xam nh|p min cd till dam bdo lugng nude ttrdi cho 120 ha Ifla frong 15 ngiy. Ngoii ra, vide thay doi lich tiidi vy vd dp dyng phuang phip tudi tilt kiem nude eung cd till han che inh hudng cua viec thilu nude do xam nhap mdn tal khu vyc nghien cflu.
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