BQ CONG THUDNG
CONG TY CO PHAN BONG
MI^N
BAG
BAO
CAO
TOMG
K^r
De
tai:
"NGHIEN
ctru THdl
VU VA CAC
BI$N
PHAP KY THUAT
TRONG BONG NANG SUAT CAO PHU HOP
V6l
CAC VUNG
DOI NUI
6
LAI CHAU"
Thuc hien theo Hgp ddng sd
115.09
RD/HD-KHCN ky ngay 04
thing
03
nam 2009 giira
Bd
Cdng thuong va Cdng ty
Co
phan Bdng Miln Bac

de tai 3
1.2.1.
Muc tieu khoa hgc cdng nghe 3
1.2.2.
Muc tieu kinh te xa hdi 3
1.3.
Thdi gian va dia diem nghien cuu 4
Phan 2: Tong quan tai lieu 5
2.1.
Nhimg nghien
ciiu
ve thdi vu gieo bdng 5
2.2.
Nhumg nghien
ciiu
ve mat do gieo trdng 5
2.3.
Nhimg nghien cuu ve lieu lugng phin bdn 8
2.4. Nhimg nghien cuu ve bien phip bim nggn tia cinh 9
2.5.
Nhiing nghien cuu ve
sir
dung thudc trir cd tren cay bdng 10
2.6.
NC va ap dung cic BP ky thuat tdng hgp trong canh tic bdng
11
Phan 3: Vat lieu, noi dung va
phvong
phap nghien
ciru

Die
diem thdi tiet khi hiu
ciia
Phong Tho - Lai Chau
21
4.2.
NC inh hudng
ciia
thdi vu gieo
din
STPT vi ning suit
VNO 1
-2
24
4.2.1.
NC inh hudng
ciia
thdi vu gieo
din
STPT
ciia
gidng
VNO 1
-2 24
4.2.2.
Nghien cuu inh hudng
ciia
thdi vu gieo den siu benh hai 25
4.2.3.
Cic yeu td cau thinh nang suit vi ning suat bdng

ciiu
inh hudng
ciia
mat do gieo trong dieu kien gieo so le 35
4.6.
De xuat mot sd bien phip ky thuit bd sung cho quy trinh ky thuit 39
sin xuat bdng nang suit cao tai Phong Thd - Lai Chau.
Phan 5 : Ket luan va de nghi 41
5.1.
Ket
luan 41
5.2. Dl nghi 41
Phan 6: Tai lieu tham khao 42
A. Tii lieu Tiing Viet 42
B.
Tii lieu Tieng
nude
ngoii 43
Phu luc
1:
Mot sd ylu to khi tugng Mudng Lay thing
4-11/2009
Phu luc 2, 3, 4
Phu luc 5, 6, 7
F F
Phu luc: Sd lieu phan tich dat
BIEU THONG TIN
1.
Ten de tii: Nghien
cim

1-
Phan Qudc Hien Ky su Ndng hgc
2-
Nguyen Van Trung Ky su Ndng hgc
4-
Nguyen Chi Thinh Ky su Ndng hgc
5-
Nguyen Van Dinh Ky thuat vien
8. Muc tieu nghien cuu:
Xic dinh mot sd bien phip ky thuit
phii
hgp trong sin xuat bdng tai viing
niii
Phong Thd gdp pin hoin thien qui trinh ky thuit tham canh bdng ning suit cao
phii
hgp vdi dieu kien dat dai vi trinh do canh tic vi tip quin cua ddng bio din tdc Lai
Chau.
9. Ndi dung nghien
ciiu:
- Nghien
ciiu
inh hudng cua cic thdi vu gieo den den sinh trudng phit trien vi
ning suit bdng lai
VNOl-2.
- Nghien
ciiu
inh hudng
ciia
cic bien phip ky thuit: xu ly thudc diet cd trudc khi
gieo,

vii mac,
\
7 7 7
S
chan man, quan io, det hing thd cim nhung hien nay do sin pham vii, quin
io,
chin min sin xuat nhieu, gii ci re phu hgp vdi
tiii
tien
ciia
ngudi ndng din
va dugc van chuyen den bin khip mgi noi nen ngudi dan mua rat thuan tien.
Mat khic, dong bao trdng giong bdng cd dia phuang cho ning suit thap 4-5
ta/ha, chit lugng xa khdng dim bio, chieu dii xa ngin (trung bmh chi dat
15-17
mm) khdng dip
iing
yeu cau cho che bien cdng nghiep, han niia gii ci thap nen
sin xuit bdng dia phuang ngiy bi mai mot, dien tich ngay cing bi thu hep.
y F
F
Nam 2007, Cdng ty Bdng mien Bac da dua cic gidng bdng lai
VNI5,
VNOl-2 trdng thu tai mot sd xa tren dia ban huyen Phong Thd, Than Uyen vdi
dien tich 50 ha. Ket qui cay bdng sinh trudng phit trien tdt cho nang suit trung
/
t
binh dat 13-14 ta/ha. Cdng ty da thu mua het toin bd sin pham kip thdi cho ba
F F
F

cii
khoa hgc bd sung hoin thien qui trinh
sin xuat bdng cho vimg mien mii li het
siic
cin thilt.
Xuit phit hi yeu ciu thuc tien tren, chiing tdi tiln hinh thuc hien dl tii
"Nghien
ciru thdi vu vd cdc bien phdp ky thudt trdng bdng ndng sudt cao
phii
hap vdi viing ddi niii Lai Chdu "
1.2. Muc tieu cua de tai
1.2.1.
Muc tieu khoa
hpc
cong nghe
Xac dinh mot sd bien phip ky thuat phu hgp trong sin xuit bdng tai viing
mil Phong Thd gdp phan hoan thien quy trinh ky thuat tham canh bdng nang
F y
F >
suit cao phu hgp vdi dieu kien dit dai, trinh do canh tic vi tip quin cua ddng
bao dan tdc tinh Lai Chiu.
1.2.2. Muc tieu kinh te - xd hoi
- Tren ca sd ket qui nghien
ciiu
cic giii phip ky thuit ap dung vio sin
xuat se gdp phan nang cao ning suit, hieu qui kinh te cua cay bdng, tir dd
khuyen khich ndng din manh dan trdng bdng, thiic day viec md rgng dien tich
F
vi ting sin lugng bdng xo cung cap cho nginh cdng nghiep Det - May trong
nude.

ciru
ve thdi vu gieo bong trong va ngoai
nirdc
Thdi vu gieo trdng cd tinh chat quyet dinh tdi nang suit ciy bdng. Viec
xac djnh thdi vu an toin, thdi vu gieo bdng thich hgp ciing li mot vin de phiic
tap,
chiu su chi phdi cua hing loat cic yeu td nhu dieu kien khi hau thdi tiet,
die
tinh gidng, tap quin canh tic, quy luat phit sinh phit trien cic
loii
sau benh hai
trong nam. Tuy nhien, vdi nhiing viing trdng bdng hoan toan dua vio
nude
trdi
F F F F
thi yeu td chinh quyet dinh thdi vu li lugng mua vi
sir
phin bd mua trong nim.
O cic viing trdng bdng d
vT
do cao,
miia
ddng cd tuyet, phii dgi nhiet do
dat cao tren 13-14 C mdi bat dau gieo. Ndng dan viing luu vuc song Duong Tir -
F F F F
Trung Qudc gieo bdng vio giura tiet cdc vii den lap ha tir 21/4 - 6/5. Nhung d
cac
nude
chau Phi, mudn dat nang suit cao phii gieo bdng sdm vio
liic

din
5/6 duang lich, rieng vung mil Tiy Bac gieo bdng tu 5/5
din
25/5 cho nang suit cao.
2.2.
Mot so nghien
cihi
ve mat do gieo trong bong
Mat do li ylu to quan trgng inh hudng rat
Idn
den cic ylu td cau thinh
nang suit va cic chi tieu sinh ly khic lien quan den ning suit. Tuy theo dilu
kien dat dai, khi hau va dieu kien canh tic
ciia
viing, vdi moi giong muon phit
huy het tiem nang nang suit thi cin phii xic dinh dugc mat do tdi thich. Theo
Ly Vin Binh va Phan Dai Luc
(1991),
d Trung Qudc muon ning cao ning suit
bdng trudc het phii quan tam den dien tich li, phii dieu chinh hoat ddng quang
hgp d cay bdng lien quan den dieu kien ngoai cinh De cd chi sd dien tich li
toi uu, ngudi ta cd the dung cic bien phip ky thuat nhu dilu chinh mat do gieo
trdng, phan bdn, che do
nude
tudi
[2].
F
y
t F
Tren the gidi, mat do gieo trdng cho bdng thay ddi rat

khoing
each
hang thuin
Igi
cho cdng tic thu hoach. Ket qui nghien
ciiu
ve mat
F
y
F
do tai Texas
ciia
Landivar cho thiy, khi ting mat do gieo trdng tu 3,7 den 5,5
cay/foot (tuang duang 12
din 18 ciy/lm^)
vdi khoing cich hing li 38 inch
(tuang duang 0,965 m) thi nang suit bdng cd xu hudng giam. Ong dua ra
khuyen cao ve mat do gieo trdng cho vimg niy la 30.000 den 60.000 ciy/miu
Anh
(hrang
duang 74.000
din
128.000 ciy/ha)
[18].
Theo Vii Cdng Hau, tai Viet Nam, doi vdi cic giong bdng
luoi
chi nen
gieo d mat do 4 van cay/ha. d nhiing vimg cd nhiet do cao vi do im khdng khi
cao thi khdng nen trdng qui diy. Gidng cd cinh qui dii mat do khdng dugc
vugt qui 3 den 4 van ciy/ha. Ddi vdi cic gidng cinh ngin cd

Quing Nam
F
y F
ciing cho thay: khi tang mat do gieo trdng thi thdi gian sinh trudng tir gieo den
tin thu ngin lai, sd qui/m vi nang suit ly thuyet cd xu hudng ting[6].
Tai
vimg
F
Duyen hii Nam Trung Bd
nude
ta, mat do cua gidng bdng lai
VNO
1-2 trong
dieu kien khdng xir ly PIX cho ning suit cao nhit li 7,5 van ciy/ha.
Theo Duong Xuan Dieu (2003) trong pham vi mat do nghien cuu tir 3,7
van ciy/ha den 12,5 van ciy/ha, khi ting mat do gieo trdng, cic chi tieu chieu
cao cay, chi so dien tich li tang theo
sir
tang cua mat do gieo trdng d mgi giai
doan. Sd
qui/m^
vi nang suit bdng dat tdi da d mat do 7,5 van ciy/ha, sau do
>
F F
Ft
giim dan. Mat do cho ning suit cao nhit niy
iing
vdi chi sd dien tich li tdi da li
F F
> >

ciy/m^.
2.3.
Mot so ket qua nghien
ciru
ve phan bon cho cay bong
F F F F F F
Phin bdn cd inh hudng den ning suit vi cic yeu td ciu thinh ning suit
F
"%
F F F
nhu sd qui/m , khdi lugng qui, nhung khdng inh hudng den chit lugng xo
y
F
F
bdng. Khi lugng dam bdn ting thi chieu cao ciy, sd cinh qui vi sd qui/cay
F F
ciing tang. Cic nghien
ciiu
cho thiy lugng phin bdn cho bdng dat
hieu
qui nhit
trong dieu kien trdng bdng thim canh cd phu ming polyethylene li
100kg
N +
40kg
P2O5
+ 50kg
K20/ha
.
Tai An Do, tren cic vimg bdng cd tudi ngudi ta bdn dam vdi lugng hon

ciiu
cua Vii Xuin Long cho thiy muc phin bdn cing cao ty le
thinh qua cing tang. Bdn phin vdi
miic
240 kg N + 80 kg
P2O5
+ 80 kg
KjO/ha
cho sinh trudng chilu cao ciy, so lugng hoa qui tren ciy, khdi lugng qui vi
F F
nang suit bdng cao nhat.
Lieu lugng phin bdn cing ting thi thdi gian sinh trudng hi gieo den tin
thu cd xu hudng dii han. Dong thdi sd qui/ciy, so
qui/m^
ning suat ly thuylt
tang. Tuy nhien, hieu qui kinh tl dat cao nhat d lilu lugng phin bdn 90 kg N +
45 kg
P2O5
-I- 45 kg
K20/ha.
Cic lilu lugng phin bdn khic nhau inh hudng
khdng ding kl den phim chit xo bdng (Le Quang
QuyIn,
Tran Thanh Diing
2003).
Tai viing Mai Son - Son La, theo tic gii Do Khic
Ngii
(2002) lugng phin
bdn cho giong bdng lai VN20 d
miic

100 kg + 50 kg + 50 kg/ha vi bdn 3
lin/vu
cho nang suit
va hieu qui cao.
2.4.
Mot so ket qua nghien
ciru
ve bien phap bam ngon tia canh
Bam nggn (hay ngat nggn) li mot bien phip ky thuit rit quan trgng, do nd
anh hudng den tinh hinh sinh trudng vi nang suit cua ciy bdng. Bim nggn qui
sdm hay qui mudn deu giy ra hieu qui xiu. Vi neu bim nggn qui sdm, sd
lugng cinh qui it vi cinh nich lai phit trien manh. Cdn bim nggn mudn qui thi
khdng cd tic dung ting ning suit mi sd cinh qui vd hieu lai tang do nu hoa
rung nhieu.
Vien Khao
ciiu
Ndng Lim da tdng ket, nhirng noi bim nggn sdm, chi de
fv
F F F
lai tren cay 5-6 canh qui din den ning suit khdng cao. Nhirng nai bim nggn
qui mudn, de nhieu cinh qui nen ciy khdng du
sue
nudi, ddng thdi qui phia
tren thudng bi rung cdn nhiing qui phia dudi nhd vi khd nd. Tdm lai, bim nggn
^
F
sdm qua hay mugn qui deu cd hai cho ning suit bdng
[12].
F F
Nhirng nghien

cinh qui, lim tang sd
qui/m^
vi ting nang suat bdng so vdi ddi chiing ve mat sd
tuyet ddi.
'
y
F
g,.,r
Ket qui nghien
ciiu ciia
Choi, B.H. ve thdi ky ngit nggn cho ciy bdng
gidng CAMD-2-2 cho thiy, viec ngit nggn sdm qui (40 ngiy sau gieo) se lim
^
F F
glim nang suit bdng. Ngat nggn vio giai doan 60 ngiy (tuang
iing
vdi 14 canh
qui/cay) cd tic dung lim ting nang suit bdng 16, 69% so vdi ddi chiing. Trii
lai,
viec ngat nggn mugn vio giai doan 70 ngiy sau gieo (tuang
iing
vdi
16
cinh
qui/cay) chi lim ting nang suat 8,36% so vdi khdng ngit [13].
Qua thuc tien sin xuit d cic viing trdng bdng phia Bac cGng di dua ra
khuyen cio chung la nen ip dung bim nggn cho nhung rugng bdng sinh trudng
manh, trdng diy du mat do, chieu cao ciy dat 90 cm vi hing bdng da khep tin.
hoac khi cay bdng dat 12 cinh qui cho nang suit bdng hat cao.
2.5. Mot so ket qua nghien

F F
thudc tru cd cho sin xuit bdng.
Viec nghien cuu sir dung thudc trir cd trong sin xuit bdng d phia Bic
dang trien khai nghien
ciiu,
nhung
chii
yeu li sir dung cic loai thudc diet cd d
7
F
giai
doan chuan hi dit, phun trudc khi gieo bdng
7-10
ngiy.
2.6. Mot so ket qua nghien
ciru
va ap dung cac bien phap ky thuat tong hgp
trong canh tac bong.
Viec ip dung tdng hgp cic bien phip ky thuit ddi vdi giong bdng lai
VN20 trong ci hai trudng hgp ting mat do, cd phun chit dieu hoi sinh trudng
X
F F F
hoac khdng tang mat do deu lim ting ning suit so vdi ddi chiing tu 24,28% den
37,12%
vi mang lai hieu qui kinh te cao,
Iii
thuin cao han ddi
chiing
tu 1,1
trieu den 1,9 trieu ddng/ha (Dinh Quang Tuyen, 2004).

mua nen
viec xudng gidng diing thdi vu, gieo bdng vdi mat do hgp ly, vi ip dung cic
>
F y
F
bien
phip ky thuat
phii
hgp vdi dieu kien sin xuit cua ddng bao din tdc li rit
^
F
can thiet.
12
PHAN
3
VAT LIEU, NOI DUNG VA
PHT/ONG
PHAP NGHIEN
ClTU
3.1.
Doi
tu-oTig
nghien
cihi
*
Gidng bdng VNOl-2:
- VNOl-2 li gidng bdng lai cua Vien nghien
ciiu
ciy bdng vi ciy
cd sgi, cd ngudn gdc tir td hgp lai

Hoat chit: Paraquit
+ Do ddc: Nhdm 2
+ Co che tic ddng: Tiep
xiic
-I-
Cdng
dimg :
Diet cd trudc khi trdng, diet cd giiia hing, giura
ludng.
+ Luu y
:
Phun dinh hudng vio cd, trinh phun vio phin xanh cua ciy
- Thuoc tru cd Ally 20 DF :
+ Hoat chat:
Mesulfuron
methy.
Chi
phim dang huyen
phii
khd.
-I-
Do ddc: Thudc nhdm dgc 3
+ Ca che tic ddng:
Li thudc trii cd chgn lgc, ndi hap, hau niy mim.
13
Thudc xam nhap qua li vi di chuyen khip ciy cd
din
tin thin,
F
xw

sinh
trudng, phit trien vi ning suit bdng lai
VNOl-2.
3.3.
Phvong
phap nghien
ciru
- Phuong phip thi nghiem ddng rugng: Cic cdng thiic thi nghiem dugc
F
t
F
y
mj
y F
/St
bd tri theo kieu khdi diy du ngiu nhien, 3 lan nhic lai, dien tich mdi d
tiiy
thudc
vio timg thi nghiem. Cic thi nghiem dugc trien khai thuc hien tai 3 bin thudc 3
xa Khdng
lio,
Hoang Then vi Xi Bin Lang, huyen Phong Thd, tinh Lai Chiu.
Thi nghiem 1: Nghien cuu inh hudng cua thdi vu gieo den sinh trudng
phat trien vi nang suit bdng
VNOl-2.
Thi nghiem gdm 6 thdi vu (Cdng thiic)
Thdi vu
Tl:
Gieo ngiy 20/4; Thdi vu T2: Gieo ngiy 30/4
Thdi vu T3(d/c): Gieo ngiy 10/5; Thdi vu T 4: Gieo ngiy 20/5

Thi nghiem bd tri theo kieu khdi diy du ngau nhien, 3 lin nhic lai, dien
tich 200
mVd.
Dien tich toin thi nghiem
2800m^
ke ci dien tich bio ve.
Thi
nghiem gieo bdng ngay
15/5/2009.
F
y
t
F
Phun thudc 1 lin vio ngiy 6/5/2009 (thdi diem phun thudc tru cd 10 ngiy
trudc khi gieo bdng, phun 30 binh/ha, mdi binh
12
lit, phun deu
true
tiep len ciy cd
Mat do gieo bdng 5,5 van cay/ha, khoing cich gieo 40 cm - 45 cm .
Lugng phan
bdn:
100kg Ure + 300kg NPK
/ha.
Bdn
Idt
300kg NPK
(5:
10:3)
Bdn thiic 2 lan: Lan

P3:130kg
Ure +
300kg NPK
+ 25kg KCl tuong img
75N
+
3OP2O5
+
24K2O.
+
P4:
160kg
Ure +
300kg
NPK + 50kg KCl tuong
iing 88N + 3OP2O5
+
39K2O.
+
P5:190kg
Ure +
300kg
NPK + 75kg KCl tuang
iing
102N +
3OP2O5
+
54K2O.
- Thi nghiem bd tri theo kilu khdi diy du ngiu nhien, 3 lin nhac lai, dien
9

sinh trudng phit trien vi nang suit bdng
VNO
1-2:
- Thi nghiem gdm 4 cdng thiic (4 mat do):
CTl (D/C): 4,2 van ciy/ha (khoing cich gieo 80cm x 30cm x
Iciy)
CT2:
5,0 van ciy/ha (khoing cich gieo 80cm x 25cm x
Iciy).
CT3:
5,5 van cay/ha (khoing cich gieo 70cm x 26cm x
Iciy)
CT4:
6,0 van ciy/ha (khoing cich gieo 70cm x 24cm x
Iciy)
- Thi nghiem bd tri theo kilu khdi day
dii
ngau nhien, 3 lin nhic lai, dien
tich
lOOmVd.
Dien tich toin thi nghiem
1500m^
kl ci dien tich bio ve.
- Thi nghiem gieo ngiy 25/5/2009.
- Lugng phan bdn:
100kg
Ure + 300kg NPK/ha.
16
Thi nshiem 5: Anh hudng
ciia

Phuffng
phdp theo ddi ddnh gid ray xanh, benh xanh
liin,
benh moc
suffng.
»>f
benh dom
Id
(theo phuong phip thdng dung theo quy dinh cua nginh bdng).
* Riy xanh :
Theo ddi riy xanh dinh gii cip riy hai d thdi ky 60 - 70 ngiy sau gieo
bdng
(chii
yeu quan sit li d tang giira vi ting nggn cua ciy bdng).
Cap 0 : Li khdng hi hai.
Cap
1
: Li chdm cong vi cd bieu hien hi hai
Cip 2 : 1/3 sd li tren ciy hi cong vi cd bieu hien ving.
Cap 3 : 2/3 sd li tren ciy hi cong vi chuyen miu ving
Cap 4 : Toin bg li bi cong, ving vi chdm chiy.
F
A
7
Cap 5 : Li hi cong nhieu vi chuyen miu ving dd.
* Benh hai:
Dieu tra
100
cay/5 diem cheo gdc.vio thdi ky 70 - 80 ngiy sau gieo bdng,
tinh ty le benh (%) va chi so benh (%) theo cic cdng thiic sau:

F
• Cap 2:
>5-15%
dien tich li hi benh, hoac <5% dien tich li hi benh
va 5% sd qui thdi do benh.
• Cap 3:
>15-30%
dien tich li bi benh, hoac 5-15% dien tich li hi
benh va
10%
sd qui thdi do benh.
• Cip 4: >30-50% dien tich li bi benh, hoac
15
-30% dien tich li bj
benh va
15%
sd qua thoi do benh.
• Cip 5: >50% dien tich li bi benh, hoac 30-50% dien tich li hi
F F
benh vi 20% sd qui thdi do benh.
3.4.
Cac chi tieu theo ddi
- Cac chi tieu ve sinh trudng, hinh thii, ning suit vi siu benh hai tren ciy
bdng dugc quan
trie
theo phuong phip thdng dung theo quy dinh cua nginh
bong.
- Thdi gian sinh trudng (ngay): sd ngiy tu khi gieo den tan thu .
- Cac chi tieu sd cinh qui, cinh
due:

khic;
tong thu tir mdi d thi nghiem sau dd xic dinh hieu qui kinh te.
3.5.
Phirong phap canh tac trong cac thi nghiem
- Cic thi nghiem dugc bd tri tren chin dit dai dien cho viing sin xuit vi
trong dieu kien phu thudc
nude
trdi hoin toin. Dit ddi cd dia hinh ddc (do ddc
ft
' ^
X
dudi 20 ), loai dat den thinh phin ca gidi trung binh, ting canh tic tir 30 - 40
cm (dit trdng ngd vu 2008).
F F
7
/
- Dit sau khi lim sach cd tien hinh xdi xio nhe, trdi mua du im tien hinh
gieo hat (trir thi nghiem sir dung thudc diet cd trudc
liic
gieo).
- Bdn
Idt
bang phin NPK Lim thao (5:10;3 ). Bdn thiic bing phin dam
ure va kali vio giai doan 25-30 ngiy ( 50% Ure + 50% KCl) vi 50 -55 ngiy sau
gieo (50% Ure + 50% KCl).
- Cic bien phip ky thuit canh tic khic deu dugc thuc hien tren co sd tuin
thu nguyen tic sai khic duy nhit cho timg thi nghiem.
19
3.6.
Phu-Qfng

duong vdi Phong Thd ).
\Chi tieu
ThangV
1
2
3
4
5
6
7
8
9
10
11
12
Lugng mua
(mm)
25
51
68
152
239
443
485
293
159
37
62
11
Nhiet do TB

TB (%)
76.6
76.6
78.4
78.8
81.8
85.6
87.4
86.8
81.8
81.0
80.5
74.4
Ngu6n:Cuc thong ke Lai Chdu so lieu trung binh 5 nam 2004 - 2008.
21
Qua nghien
ciiu
cic sd lugng khi tugng vi
die
diem sinh trudng phit
•
' '
7
trien
ciia
cay bdng cho thiy d diy cd the gieo bdng vio thing 4, thing 5. Giai
doan niy lugng mua trung binh thing dat
152
- 239 mm, mua khdng qui nhieu,
dii

tirgng
tiir
thang 1-12
viing
Than uyen (Tirong
dirang
vdi Phong Tho)
600
500
400
300
200
100
0
-•—
Thang
-•—
Luang
mua
Nhiet
d6
TB
' SO
gid
ning
(gid)
^K m ^ ^ ^ ^
V
•',i
1 2 3 4 5 6 7 8 9 10 11 12