NGHIEN CCrU-TRfiO TOI
GIAI PHAP ON D M NANG SUAT LUA VU DONG XUAN
6 DONG BANG SONG H 6 N G
PGS.TS NGUYEN VAN VIET
Vi(§n Khoa hoc H6r\q r\qW\$p V\$t Ham
(SOLUTION FOD (?>TABILITY Of WINTED-cSPDING DICE PDODUCTION IN THE D E D DIVED DELTA OF
VIET NAM
Climate change strongly Impact agricultural production of Vietnam. The growing, developing and forming crop yield depend on variaty of factors, In which climate conditions are the main factor. Further more, the paper discuss the result of research on the
relationship between the climate factors and winter- spring rice crop yield on the data base of the period
1961-2011. Consequently, to find the cause of the years with low rice crop yield; then, to suggest the strategies to be adapted with climate and weather anomalies in the Red River Delta.
The results showed that, up to now, cold and warm weather have still considered as natural disaster for winter-spring rice season in the north of Vietnam.
Based on the new technologies procedures and rice varieties with short duration, if the farmers move from winter-spring rice to late-spring rice, impasts of disadvantage climate on rice production will be diminished. Late-spring rice will be new croping pattern with high economic efficiency and sustainability in the Red River Delta.
Keyword: Winter-spring rice, late-spring rice, climate, climate change, wether, Red River Delta
I. Dat van de
Ddng bang song Hong la vung s^n xuat lua truyen thong v6i dien tfch 1,15 trieu ha, chiem 15,34%
dien tfch trong lua ca nudc (7,513 trieu ha). Day la vung co nang suat lua dong xuan cao nhat ca nudc, dat 57,3 ta/ha (2001), tang len 66,9 ta/ha (2011) va cao hdn vu mua.
Mac du trong thdi gian qua, nhieu tien bo ky thuat ve lua xuan da dUdc nghien cufu va chuyen giao vao san xuat, gop phan tang nang suat va san IUdng lua cua vung, nhUng do bien doi khf hau va nhiJng thay doi bat thadng cua thdi tiet ma nang suat lua ddng xuan khdng on djnh. Do vay, nhdm nghien ciJu (gom PGS.TS Nguyin Van Viet, TS Pham Dffc Hung Vien Khoa hoc Nong nghiep Viet Nam; TS Trin Xuin Djnh Sd Nong nghiep va Phat triin Ndng thon tinh Thai Binh;
ThS Nguyin Thj Vang Sd Nong nghiip va Phat triin Ndng thon tinh Ha Nam va PGS.TS Nguyin Van
Viit Trung tam Khi tuang Nong nghiep, Vien Nghien cffu Khf tffdng Thuy van va Bien doi Khf hau) da nghien cijfu va de xuat cac giai phap nham giai quyet van de nay.
II. Phuong phap nghien cihi
Tham khao tai lieu ve thdi tiet khf hau tai Trung tam Khf tUdng Ndng nghiep (Vien Nghien cufu Khf
o- u . onno Hoot tfong So thang 1.2012 j ^ Q ^ H O C
89
NGHIDN CCrU TRfiO 061
ta(?ng Thuy vSn v^ Bi6'n d6i Khf h§u), s6 li§u thd'ng k§ v^ skn xufi't lua cDa trung Udng v^ ckc tinh.
PhUdng phdp chuySn gia: Mdi ckc chuy§n gia cd kinh nghidm trong nghl§n cijfu vk chl d^o skn xud't cua ckc vi$n nghidn CLTU, Cgc tr6ng trpt, Sd ndng nghidp vd phdt triln ndng thdn hdi thdo ddng gdp y kid'n vd vid't cdc chuydn dd.
- PhUdng phdp didu tra: Didu tra theo phUdng phdp PRA, didu tra sdn xud't theo 3 tidu vung sinh thdi d D6ng bdng sdng H6ng. Sd' lidu khf tu<?ng thu thdp tU Trung tdm Khf tu^ng Ndng nghidp.
Sd' lidu thu dUdc xii ly theo phUdng phdp thd'ng kd sinh hpc.
in. Bet qua va thao loan
1. su thay dii cue thdi tiit trong vu ddng xuin vi mii quan h$ cua thdi tiit vdi sin xuit lua ddng xuin
1.1. Sff thay dii cua thdi tiit trong vu ddng xuin
Kdtqudt6ng hpp nhidu ndm cho thdy, thdi tidt vg ddng xudn bidn ddng thdt thudng, nhdt Id 5 ndm trd l9i ddy, m6i ndm mdt d^ng hinh khac nhau. SU bidn ddng Idn chCi ydu 6 thang 12 vd thdng 1, bidn dO thay ddi cd xu hudng lan rOng sang thang 2 vd ra cd sau tidt ldp xudn.
Trong 5 vy tU 2007-2011 cd 3 vg nghidng vd dm, 2 vg nghidng vd rdt va cac d0t ret khdng trung nhau.
Tfnh toan s6 Hdu nhidu ndm cho thay bidn do ndn nhidt cdc thdng chuyen tidp tU.ddng sarig xudn Id rat Idn.
1.2. Mii quan hi cua thdi tiit vdi sin xuat lua ddng xuin
Nghien cUu moi quan hd giufa
cdc ydu td' thdi tid't vdi sdn xudt lua ddng xudn thdy rdng, sg thay ddi nhidt dO Id mOt trong nhOng ydu td quan trpng dnh hudng ddn ndng sud't lua. Theo dd, cdc giai do^n sinh trudng vd phdt tridn khde nhau cua lua ddng xudn ydu cdu didu kidn nhidt dO khde nhau. TUdng Ung vdi cdc giai dogn m? - cdy - dd nhdnh Idm ddng trd bdng cua cdy lua thi didu kidn thudn I0i theo quy ludt chung Id rdt Ignh trung binh dm - dm, tUc Id rdt giai dogn mg, Ignh giai dogn cdy, trung binh giai dogn dd nhdnh, dm giai dogn Idm ddng vd trd bdng.
Qua cdc tdi lidu nghidn cUu trudc ddy cho thd'y, nhidt dd gidi hgn thdp cua mg ddng xudn Id 13°C, dudi ngudng dd 3-4 ngdy lidn tgc vdi tdng dd hgt nhidt dd >
4°C Idm mg bj chd't. Phdn tfch sd lidu khf tupng 47 ndm (1961-2007) thdy rdng, gieo mg vdo ddu thdng 2 cd mUc ddm bdo khdng bj rdt hgi ch? d xdc sud't trung binh. Do vdy, ndu gieo mg vao thdi dilm ndy cdn chu ddng bidn phdp tdng cudng chdng rdt, ddc bidt Id che phu nilon cho mg.
Thdi dilm lua trd an todn Id thdi dilm nhidt dd vupt ngudng 25°C.
Kdt qud nghidn cUu cho thdy xdc sudt ddm bdo nhidt dd trdn 25°C (trdn 80%) d dgi da sd cdc dja
phUdng Id ddu thdng 5 ddn trung tudn thdng 5.
2. Tinh hinh sin xuit lua v[f ddng xuin vi nguyin nhin inh hudng din ning suit
Ndng sudt lua ddng xudn vung Ddng bdng sdng Hdng tdng ddng k l qua cdc ndm, tU 53.1 tg/ha (1998) tdng Idn 66,9 tg/ha (2011).
Lua ddng xudn cung Id vg lua cd ndng sudt cao nhdt trong ndm, cao hdn 15-20% so vdi vg mua.
Su thay ddi thdi tilt cd mUc dnh hudng khde nhau ddi vdi cdc trd lua. Trong didu kidn biln ddng cua thdi tidt, trd xudn sdm cd mUc sgt gidm ndng sudt Idn nhdt, trong khi trd xudn mudn ludn cd ndng sudt dn djnh. Sd lidu dilu tra tgi Thdi Binh cho thdy ndng sudt lua ddng xudn 2007 gidm 22,1% so 2006.
Trd xudn mudn (dde biet Id lua lai) ed mUc sgt gidm ndng sudt ft hdn (11,0-18,5%) (bdng 1). Nguydn nhdn khdeh quan lam nang sudt lua ddng xudn 2007 bi giam sut Id do didu kidn thdi tiet bat Ipi, ddc bidt Id nhidt dd thdng 2 eao, Idm mg bj gid dng, cdc d0t rdt thdng 4 gdy dnh hudng d i n phdn hod ddng vd trd bdng, sd gid ndng va bUc xg trong ede thdng 3, 4, 5 eung thdp hdn trung binh nhilu ndm, lam sgt gidm qud trinh tfeh luy chdt khd, ddn ddn bdng bd, ft hgt. LUpng mUa ed
Gitfng Ilia - trii lua
Xuin sdm VN-10 Xuin muOn Khang ddn
Q-5 Lua lal
NAng sutft 2006 (t9/ha)
70,64 71,20 73,72 74,24
Ning suA 2007 (t9/ha)
55,04 58,00 61,59 66,06
Mi}c sgt glim tfi/ha
15,60 13,02 12,03 8,18
T9I$(%)
22,1 18,5 16,5 11.0 Bing 1. MUc syf giim nkng suit Ida d ckc trk lua, gidng lua vu xuin cd thdi tiit im
(2007) so vdi nkm binh thudng (2006) t^i Thki Binh
90 K M O A H o ' c S ^ ^'^^"9^2012
NGHI6N CQU - TRfiO £)0l
vg thd'p hdn trung binh nhilu ndm, gdy bd't Ipi eho sinh trudng vd phdt trien cua lua ddng xudn. Nguyen nhdn ehu quan la nhilu dja phUdng gieo ed'y sdm hdn Ijch thdi vg ndn gap ndng, Idm ma bj gid dng, khi cay lua phdn hod ddng sdm trong thang 3 va trd trudc 25.4 gdp nhidt do thd'p ndn trd khdng thudn Ipi.
3. Giii phip in djnh ning suit lua VIJ ddng xuin 6 Ding bing sdng Hing
3.1. DiSu chfnh thdi vij gieo ciy dffa trin thdi gian trd an toin
Phdn tfch eac y i u td tUdng quan giQa thdi d i l m phdn hda vd trd bdng thfch hpp cho vide hinh thanh sd hoa, thg phdn, chd't lupng hat phan trong vg xudn d mdt sd nam ret dam, ret hgi, nam am cho thay thdi d i l m lua xudn trd bdng cho nang suat cao nhd't la tU 10- 20 thdng 5 dUdng Ijch. 6 thdi d i l m nay djch v l trudc 30-35 ngay (dilm phdn hda ddng) tan suat nhiet dp trung binh ngdy Idn hdn 25°C d i u tren 85%, nen nhiet td'i thfch hpp cho lua nd hoa, thg phdn vdi tdn sud't tren 95%.
TU phdn tfeh trdn thdy rang, d l dgt nang sudt lua ddng xudn cao va dn djnh, y i u td then chdt la d i l u khiln cho lua trd vao thdi d i l m an toan. N l u Id'y thdi d i l m lua trd an todn la 1-20 thang 5, cd t h i tfnh ngupe thdi d i l m gieo ed'y eho tUng gid'ng lua vdi thdi gian sinh trUdng khac nhau. Vdi phUdng phap tfnh ngupe nay, tra ngan ngdy (120-125 ngdy) nen gieo tU 5-10 thang 2.
Trong khi dd tra trung ngdy (130- 140 ngay) nen gieo sdm hdn (1-5) thang 2.
3.2. Chuyin djch tri lua va giing ]sang tri xuin mudn
Kd't qud nghidn cUu cho thd'y trd Ilia xudn mu^n cd ndng sudt cao vd dn djnh nhdt, do vdy d l chCi d^ng vdi mpi thay ddi bd't thudng cDa thdi tid't, lua xudn bao gdm cdc tra xudn sdm, xudn chfnh vg vd xudn muOn ndn chuyin djch sang trd xudn mudn gieo mg xung quanh ldp xudn. SCr dgng cdc gid'ng lua ngdn ngdy d l trd vdo thdi d i l m an todn Id ddu thdng 5. Vg ddng xudn 2009, didn tfch gieo ed'y trd xudn mudn chilm 85,5%. Cdc t?nh cd ty Id didn tfch gieo ed'y xudn mudn cao Id: Nam Djnh (99,9%), Ha Nam (98%), HUng Ydn (93%)... Ndng sudt dgt khodng 61,5 tg/ha, cao hdn ndng sudt lua chung khodng 3,0 tg/ha. Vg xudn ret 2011, Uu the t h i hien cang trdi hdn ve nang sud't cua nhdm ngan ngay, eCia lua thudn va lua lai so vdi gid'ng ddi ngay xudn sdm (Xi23). Lua lai vUpt 35,8%, lua thuan nang sud't vUpt 25,9%, ngay lua chd't lupng eung vupt 2 1 % so vdi lua dai ngay (bdng 2).
Dien tfch lua lai tid'p tgc tang, cd ed'u gid'ng phong phu, la cd sd d l ndng cao ndng sud't, sdn lupng lua vg ddng xudn. Thgc td cho thdy, trong vg ddng xudn 2011 d i l u kidn thdi t i l t bdt thudng da dnh hudng xdu tdi qud trinh hd'p thu dinh dudng, quang hpp va dd nhanh cua cdy lua, nhung cdc gidng lua lai da t h i hidn khd nang sinh trudng va phdt triln, chdng chju tdt hdn cac gid'ng lua thudn trong d i l u kien blit thudn. Ddy Id mdt d i l u kien ddm bdo d l ddy mgnh md rdng didn tfch Ilia lai trong cac vg tdi, nhdt la khi thdi tid't ngay cdng cd nhOng bien ddng bd't thudng.
3.4. l\/ld rdng diin tfch lua gieo thing
Liia gieo thing la giai phdp quan trpng d l gidm bdt chi phf ve gid'ng, cdng lao ddng, gidm gid thdnh sdn pham. Tuy nhien dien tfeh liia gieo thing can dupe bd trf tren nhOfng chdn dd't chu ddng tudi tieu, gieo tap trung theo vung d l tranh hien
Tdn gidng
Xi23i'i TX111I'' TB R-1»i
HTIi'i N97W
MftdQ Kh6m/m2
35 35 35 35 35
Bdng/
khdm
6,6 6,4 6,2 6,5 7,2
H9t/
bdng
172,5 194,6 204,5 196,5 164,0
H9t chic/
bdng 135,0 177,5 181,0 171,5 150,0
T j l f lep (%) 21,7 9,0 11,5 12,7 9,1
PI 000 h9t(g)
25,0 26,0 25,0 24,0 25,0
NSLT (t9/ha)
77,96 103,40 98,19 93,64 94,50
NSTT (t^/ha)
62,37 84,70 78,55 74,91 75,60
So gidng dai ng4y(%)
100,00 135,80 125,94 120,10 121,21
Bing 2 So sknh nkng suit vk ckc yiu td ning suit giOa ckc nhdm gidng xuin sdm, xuin mudn vi^ xuin rit nkm 2011 t^i Thki Binh: (1) Gidng lua dki ngky (xuin sdm);
(^) Gidng lua lai; (3) Gidng Ida thuin NS; (4) Gidng Ida chit lUdng; (5) Gidng lua nip;
NSLT: Nkng suit ly thuyit; NSTT: Nkng suit thi/c thu
M
3.3. Tang diin tfch lua lai
Trong dieu kien bd't thudng eua thdi tiet, liia iai gieo tra xudn mudn van cho nang sudt cao vd dn djnh.
tupng rudng khd hgn hodc bj ling khi mdi gieo, lam dnh hudng den sinh trudng cCia cdy liia. Vu xudn 2011 do ret dam, ret hgi keo ddi, nhieu dja phUdng da sur dgng
Hoat tfong
S6 thang 1.2012 K H o ^ p j ' ) ^ 91
NGHIDN CCru - TRfiO B6\
phUdng phdp gieo thing nhim khde phgc dilu kidn bd't thudn cCia thdi tilt, ddm bdo k l hogch gieo ed'y. Ndng sud't Ilia gieo thing vg xudn 2011 khd eao, tdng so vdi ndng sud't liia ed'y theo phUdng phap truyin thd'ng 5-10%.
3.5. Ap dijng cic tUn b0 ky thuit mdi vio sin xuit lua
Nhdm tdng ndng sud't, hgn ehl phdt sinh sdu bdnh hgi, gidm chi phf, hg gid thdnh, nhilu tiln bO ky thudt dang dupe ndng ddn dp dgng vdo sdn xudt nhu sCr dgng phdn bdn tdng hpp NPK thay t h i eho phdn dPn, kit hpp phdn da lupng vdi phdn trung, vi lupng, phdn bdn r l vd bdn qua Id...
da ndng cao hieu qud sCr dgng phdn bdn; cdc tiln bd ky thudt "3 gidm 3 tang", SRI nhu sCr dgng hgt gid'ng ed pham cdp td't, xCr ly hat gidng trudc khi gieo, Idm mg khay, ehdm sdc mg khoe, cay ma non, cay thua 30-35 khdm/m^, cay 1 ddnh/khdm, bdn phdn sdm vd tdp trung... dang dan trd thdnh tap qudn canh tac cua ndng ddn.
Cae bien phap ky thudt Ung phd vdi thay ddi bdt thudng ciia thdi tilt cd t h i dp dgng bao gdm:
Nim im: Cdy mg non, gieo thing va Id rudng. Bidn phdp Ung phd khi gap dm giai dogn mg vd Ilia mdi cay Id xudn sdm vd chfnh vg gdm tang thdm lupng phdn cho bdn thiic (1-1,5 kg dgm urd/sdo) d l keo dai thdi gian sinh trudng, tang sd nhanh nhim bu cho eac nhanh chfnh trd trudc bj Idp. Dilu tilt muc nude thfch hdp (3-5 cm trdn mat rudng) d l tgo dilu kidn cho Ilia de nhanh tdi da nham ddm bao sd bdng tren ddn vj dien tfch.
Bdn tang lupng phan kali cho lan bdn ddn ddng (2-3 kg/sao) d l tang tfch luy chd't khd, gidm ty Id lep.
Ddi vdi trd xudn muOn do nhidt dd khdng khf cao, cdc giai dogn sinh trudng eCia cdy liia cd khd ndng riit ngdn, do vdy cdn dilu ch?nh c h l dO chdm sdc, bdn phdn theo tUng giai dogn sinh trudng eho h<?p \<i, cdn tdng lupng phdn kali d l ddm bdo 6-8 kg/sdo.
Nim rit: Ddi vdi mg: Che phCi nilon, budi trUa khi trdi dm trdn 15°C md nilon d 2 ddu ludng 1-2 gid eho thdng thodng d l cdy mg phdt triln tdt, hgn c h l tde hgi eCia ndm bdnh.
Ddm bdo dCi dm cho mg, khdng d l mg khd qud hodc ngdp nudc.
Khi thdi tilt dm, phun phdn bdn Id hodc cdc c h l phim khde din khi mg ra r l non mdi. Ap dgng bidn phdp xiie mg cdy, khdng nhd mg d l trdnh dUt r l . Ddi vdi liia: Rudng Ilia chit dudi 20% khdng edn ddm t?a, chd't 20 din 50% thi cdn tiln hdnh ddm t?a vd ehdm sdc liic thdi tilt da dm Idn (nhidt dd trdn 20°C);
nlu Ilia chit trdn 50% khi d'm thi nhd cdy liia edn sdng d l ed'y ddn.
Khi nhidt dd trdn 20°C liia da hdi xanh thi tdng cudng bdn thiic NPK d l Ilia dd sdm vd tdp trung. Thdo nude vd bdn thiie kali khi mdt dd Ilia da ddm bdo.
IV. Ket luan va de nghi
Dilu kidn thdi tilt khf hdu vg Ilia ddng xudn thudng cd bid'n ddi bd't thudng, trong dd cd khodng 21,27% sd vg dm, 34,04% sd vg ret vd 44,66% sd vg binh thudng.
Nhu vdy d'm hodc rdt Id quy ludt td't yd'u cua vg xudn d Ddng bdng sdng Hdng. Kit qud nghidn eUu thd'y ring trong vg liia ddng xudn sd ngdy cd nhidt dd trung binh dudi 20°C trong giai dogn ely din lam ddng, sd ngdy cd nhidt dp trong khodng 20-25°C vd sd gid nang giai dogn trd d i n chfn edng nhilu
thi ndng suit liia ddng xudn cdng cao.
Cdc gidi phdp chfnh d l dn djnh sdn xudt vg liia ddng xudn Id chCi ddng chuyin djch sang trd xudn mudn vdi cdc gidng ngin ngdy cd ndng sudt chdt lUpng cao, tdng tjf Id Ilia lai vd md rOng didn tfch liia gieo thing; dp dgng ddng bd ede gidi phdp ky thudt nhu che phu nilon cho mg, gieo thing, ely mg non, 10 rudng, bdn phdn edn ddi, dilu tilt nude hpp ly vd dilu chfnh cho Ilia trd vdo thdi dilm an todn (nCra ddu thdng 5) •
Tai lien tham khao
1. Ld Quang Huynh, Nguyin Vdn ViSt, Ld Otjrc Nhon. Co sd khi h§u ndng nghidp vd thdi vu gieo cSy lua ddng xudn d mi^n BSC Vidt Nam T^p chf Khi tU0ng ndng nghi$psd 12.1988.
2. Nguyin Vdn ViSt. Tdc ddng ctja dao ddng khi h$u d6n ndng s u j t lua ddng xudn d Ddng b i n g B4C Bd. Tdp cdng trinh bi^n ddi khi h$u Vi$t Nam, Vidn Khi tuong Thujr vdn. t $ p 1 . 1998.
3. Ddo Thd Tufin vd nhdm chuydn gia, 1991. D l cd mdt vg ddng xudn d Ddng b i n g sdng Hdng dn djnh vd vOng chic (Bao cdo).
4. Nguyin Vdn Vidt, Ph^m DiJlc Hung, Nguyin Trpng Khanh, Nguyin Vdn Vidt, Nguyin Hdng Son, Ddm Quang Minh, Ph^m Bich Hidn, vd CTV. Nghidn ciJfu tinh hinh skn xu^t lua ddng xudn trong trong d i i u k i i n b i i n ddi khi h$u vd nhOng giii phdp d l I n dinh sdn xufit liic ddng xudn S Odng b i n g sdng Hdng. T?ip chf Khoa hpc Cdng nghd Ndng nghidp Vidt Nam sd 4 (9) 2008.3-9.
