KHOA HOC C 6 H G N G H I
XAC DIIMH LOAI DUIVG DfCH DIIMH DUaiMG THICH HDP DE TRDIMG THIJY CAIMH IVIDT SO LOAI RAD AIM LA
Nguyen Minh ChungS Trin Khic Thi^ Nguy&n Khic Thki San^
Hoing Minh Chiu^, Nguydn Th; An^
T6MTAT
Nghi6n ciiu duoc thuc hi^n tr^n 4 lo?i rau (rau xa Idch, rau cai xanh, rau cdn tiy vi rau mudng) vdi 3 cong thiic dung dich dinh dudng, trong do: 2 dung djch do Vifen Nghidn cuu Rau Qua Ha Npi san xuat 64 so sanh voi ddi chiing la dung djch do Vi^n Sinh hpc N6ng nghidp (Trudng Dai hpc N6ng nghidp Ha Npi) san xuat.
Ket qua nghien ciiu cho th^y: Dung djch dinh dudng ciia Vi^n Sinh hpc Nong nglii^p, dung djch dinh duong VRQl ciia Vi^n Nghien ciiu Rau QuS phii h(7p cho siai xufLt rau xa Uch, rau cai xanh va rau cin tSy.
Sau trong 20 ngay tren cac dung dich nay. nSng suit xa lich dgt tuong ting 1^ 35,46 va 35,28 ta/lOOO m^;
nang suat cai xanh tuong ling dat 38,52 vk 38.94 ta/1000 m^. Sau tr6ng 30 ngay tr^n cac dung djch nay, nang suat cin tSy tuong ung dgt 46,25 vi 46,06 ta/1000 ml Dung dich dinh dudng VRQ2 phii hpp cho san xu^t rau mudng, nang suat rau mudng d cic liia hii dat tir 44.56 d^n 63,52 ta/1000 m^. Ca 3 loai dung djch dinh duong d^u dam bSo ham lupng nitrat, chi, cadimi trong rau thip hon nhi^u so voi nguOng cho ph^p. Ham lupng nitrat trong xa lach tir 243 d^n 343 mg/100 kg tuoi, trong cai xanh tir 285 den 342 mg/100 kg tuoi.
Ham lupng chi trong xa lich tir 0,028 d^n 0.053 mg/100 kg tuoi, trong cai xanh tir 0,045 d^n 0,062 mg/100 kg tuoi. Ham luong catmi trong xA lach tir 0,005 den 0,009 mg/100 kg tuoi, trong cai xanh tir 0.004 d^n 0.008 mg/100 kg turn.
Tit]ih6a:Xa lach, cai xanh, can tiy, dung dich, dinh duong, thuy canh.
LIWBAU
Dien tich rau xanh d nude ta hien dang bi thu hep bdi qui trinh do thi h o i va phit trien cic khu cong nghiep v i 6 nhidm hoa chit ngiy cing gia tang [1]. Be gop phan dam bao nhu ciu rau xanh, thi mdt trong nhiing bien phip hieu qua dd la ap dung cdng nghe thuy canh tuan hoin NFT (Nutrient Film Technique). Cdng nghd niy cd the ting ning suit rau ti-en don vi didn tich tir 7-10 Ian [3]. Thuc tidn cho thay, tir khi ki thuit thuy canh du nhip vio Viet Nam da cd nhieu nghidn ciiu vk dung dich dinh dudng de trong ciy. Nguydn Tlii Din (1998) da khio nghidm dung dich dinh dudng Thing Long cho thay, khong thua kem gi so voi dung dich dinh dudng ciia Dai Loan ddi vdi rau i n li, hoa v i q u i vk nang suat, chat lugng [3]. Nguydn Khic Tliii Son v i Nguy§n Quang Thach (1996) d i sOr diing 8 lo?J dung dich, trong dd CO 4 loai dugc su dung nguydn bin la dung dich nhip tir Dii Loan (d/c), dung dich FAO, dung dich Knop, dung dich I Mai v i 4 loai dung dich dupe cai ti^n tit 4 dung dich nguydn ban trdn, de hi^n khai
NCS. Vi^n Nghifin ciiu Rau qua Vi^ Nghien cuu Rau qui
Tnrcmg D^ii hpc Nong lam Thai Nguyen
nghien ciiu ddi vdi cai xanh va ca chua. Ket qua cho thiy: Tit ca 7 dung dich tu pha chd vi cai tidn ddu cho ning suat cii xanh thap han so vdi su dung dung dich nhip tir Dii Loan. Dudi diy li ket qui nghien ciiu tdng the nio ve dung djch dinh dudng cho cic loai rau an li. Do dd, nghidn ciiu xac dinh dung dich dinh dudng thich hgp cho timg chiing Ioai rau an l i khic nhau, gdp phan ha gii thinh sin pham so vdi dung dich nhip ndi.
I . VAT LIEU, niQI DUNG VA PHUONG PHAP NGHIBV CUU l.Vit U$u nghidn ciiu
* Gii thi: Nghidn ciiu sir dung gii the dupe phdi trdn theo ti Id 50% gii th^ cua Vien Tho nhudng Ndng hoi sin xuat vdi 50% hot xa dira.
* Dung dfch dinh du&ng: Nghidn ciiu sir dung ddi chiing l i dung dich ciia Vidn Sinh hpc Ndng nghidp - Trudng Dal hpc Ndng nghiep H i N6i san xuit; ba dung dich dinh dudng d^ nghidn ciiu la cua Vidn Nghidn ciiu Rau Qui san xuat, duge gpi la VRQl, VRQ2, VRQ3. Thinh phan cic loai dung dich dinh dudng niy nhu sau: (-) Dung dich dinh dudng ddi chiing gdm: dung dich A (nitrat amdn, nitrat canxi, sit d dang EDTA) vi dung dich B (nitrat kali, mono-kali phdt phit, sunphit magid, sunphat mangan, chelat kem, axit boric, chelat ddng, mdlipetat amdn); (-) dung dich dinh dudng VRQl
NONG NGHIEP VA PHAT TRIEN N O N G THON - KY 2 - THANG 5/2012 37
KHOA Hpc C 6 N G NOhk
gdm: dung dich A (nitrat canxi, sit d dgng E D T J ^ v i dung dich B: amdn phdtphit, phdt phit kali, nitrat kali, sunphit magid, sunphit kdm, axit boric, sunphit mangan, sunphit dong, mdlipetat amdn); (-) dung djch dinh dirdng VRQ2 gdm: dung djch A (niti-at amdn, nih*at canxi, s i t d dgng EDTA) v i dung dich B (phdt phit amdn, phdtphit kali, nitrat kali, sunphit magid, sunphit kdm, axit boric, sunphit mangan, sunphit ddng, mdlipetat amdn).
Cic dung djch dinh dudng trong cic cdng thuc duge pha theo ty 10 thich hgp. Dinh ky ki^m tra ndng dp hull hi^u (EC = effective concentration) trong dung djch dd Uieo ddi lupng dinh dudng cin bd sung qua cic giai dogn sinh trudng, phit tridn cua ciy.
2. N^i dung nghidn ciiu
Nghidn cim duge tidn hinh vdi 3 logi dung djch dinh dudng vi 4 Ioai rau (xi lich, cai xanh, cin tiy vi rau mudng). Moi loai dung djch dinh dudng li mOt cdng thuc thi nghidm nhu sau: (-) CTl (ddi chiing):
Dung dich dinh dudng ciia Vidn Sinh hpc Ndng nghidp, Trudng Dai hpc Ndng nghidp H i Ndi; (-) CT2: Dung dich dinh dudng VRQl; (-) CT3: Dung dich dinh dudng VRQ2.
Ddi vdi x i lich, cai xanh v i can tay, nghidn ciiu duoc tien hinh tii thing 8 ddn thing 9 nim 2007.
Ddi vdi rau mudng nghidn aiu dugc tien hinh tir thing 10 nam 2007 den thing 3 nim 2008.
3. Dja d i ^ v i thdi gian nghidn ciiu: Nghidn cihi dugc tien hanh tai n h i ludi ciia Vien Nghidn ciiu Rau Qui (Hi Npi) ti-ong khoing thdi gian tir thing 8/2007 d^n thing 3 nim 2008.
4. Phuong p h ^ nghidn cuu
* He thdng thuy canh: Nghidn cihi su dung h^
thdng thiiy canh tuan hoin. H§ thdng niy gom cac dng nhira (dng cip va thoit dung djch) dudng kinh 110 mm, dii 24 m; d i t trdn gii s i t chic chin, cao 80 cm. Cic dng nhtra dugc due s i n cic 16 6,5 cm, cich nhau 15 cm dd dua ciy vio dd. Cic dng dat cich nhau 10 - 12 cm, nghidng v^ phia bd thu dung djch, dat ddc 1° so vdi m i t dat. O dau c^p dung dich, c i c dng cd hd thdng cung cap dung dich dinh dudng duoc didu chinh lupng v i tdc dd bdi khoi didu chinh.
Cac dung dich dugc dung trong Ihiing nhua, d i t cao hon dng din dung dich 0,7 m. Dung dich dugc cho chay qua cac dng nhua rdi vio bd chiia. Khi dung djch ti-ong thiing chay hdt 2/3 thi van phao ddng
bom 2 chidu d i y dung djch tir bd thu nguge 1^ b(
cip. Cii nhu thd, dung djch chay tuin hoan ti-on|
sudt thdi gian sinh trudng ciia ciy. Ciy con dupe • uom trong rg nhua cd dudng kinh 6,5 cm, cao 10 cm, 3 c i y / l rg khi dugc 2- 3 l i thit dua vio he thdng thuy canh tuin hoin.
Phuong phip bd' tri th/ nghiem: Ckc thi nghidm d^u duge bd tri theo kidu tuin tu hai hang, gdm 4 lin nhic l^i. Mdi d chgn 5 ciy dd theo dOi.
Tdng didn tich thi nghidm trong n h i ludi 150 m^;
di0n tich thi nghidm li 5 mVd.
•* Cic chi tiSu nghiin cihi:T'\kn hinh theo dOi 3 nhdm chi tidu sau: (1)- C i c chi tidu vd smh trudng theo phuong phip do, ddm, bao gdm: thdi gian sinh tiTj6ng (ngiy), sd l i / c i y Oi). chidu cao ciy vi dudng kinh tin (cm); (2)- cac chi tidu vd ning suit: khoi lugng ciy (g): cin khi thu hoach; ning suit li thuydt vi ning suit th^c thu (ta/1000 m^; (3)- cic chi Ueu v^ chit lugng sin phim: dudng tdng so (%): theo phuong phip Bectrand; chat khd (%): theo phuong phip say khd kidt; vitamin C (mg/kg tuoi): theo phuong phip Tilman; NO3" (mg/kg tuoi): theo phuong phip s i c ki ion; Pb va Cd (mg/kg hroi): theo phuong phip do tren miy cue phd.
* Xu li so lieu: Ckc s6 li^u nghidn ciiu dupe xuli thdng kd bing phin men IRRISTATE v i Excel.
1 . KET QUA NGHEN CUU VA THAO LUAN
1. Anh hudng ciia l o ^ dung djch dinh dudng ddn tinh hinh sinh trudng c i c lo^i rau trdng trii vij bing cdng ngh^ thuy canh tuin hoin
Kdt q u i thi nghidm d bang 1 cho thIy; Trong thdi vy thing 8 den thing 9 chi tidu chieu cao cay va sd li cua x i lich, cai xanh va can tiy d cdng thiic 2 ludn tuong duong vdi c i c chi tidu niy d cdng thiic ddi chung. Cy thd nhu sau:
Sau khi dua len h$ thdng thiiy canh 20 ngay cay x i lich, cai xanh d CT2 sinh tinidng tdt, tuong duong vdi ddi chiing (CTl). Cay x i lich, chidu cao ciy dat 24,5 cm; sd l i dat 15,4 l i / c i y - Tuong duang doi chiing va cao hon CT3. Ciy cai xanh, chieu cao cSy d^t 36,0 cm; sd l i dat 13,5 la/cay - Tuong duong doi chimg v i cao hon CT3.
Sau khi dua len h^ thdng thiiy canh 30 ngay. cay cdn tay d C r 2 sinh trudng tdt, tuong duong vdi d^i chung (CTl), chidu cao ciy dat 44,4 cm; sd l i dat 8,8 l i / c i y - Tuong duong ddi chiing v i cao hon CT3.
38 NONG NGHllP VA PHAT TRIEN NONG THON - KY 2 - THANG 5/2012
KHOA HOC CdNG NGHl
Bang 1. Anh huong c i a loai dung dich dinh duAig d^n chiiu cao v i s6 l i cic loai rau trdng trii vu bJng c6ng ngh$ thiiy canh tuin hoin
Vu nghien
cuu
8-9/
2007 1-oai dung dich dinh duong
CTl (d/c) CT2 CT3
10 (15) ngiy sau khi dua ten he thdng thuy canh
Chiiu cao ciy (cm) Xi
lach 13,5 13,5 11,5
Cai xanh 16,5 16,3 14,5
CSn tiy 23,5 22.5 21.0
So li tren ciy Oi) Xi lich
7,5 7,8 6,5
Cii xanh
7,7 8.0 6.8
Can tiy 6.4 5,9 5,3
20 (30) ngay sau khi dua ten h$ thdng thuy canh (tnroc thu hoach) Chiiu cao ciy (cm)
Xi lich 24.1 24.5 21.4
Cai xanh
36.2 36,0 31,5
Cin tiy 43,7 44,4 40,2
Sd la tren cay ai) Xa lich 15,0 15,4 13.9
Cii xanh
13,9 13,5 12.7
Can tiy 8,6 8,8 7.7 Ghi chu: Ch tiy theo ddi dot 1 a giai dom 15 ngiy, dot 2 a giai do^ 30 ngiy sau khi dua I6n he Uid'ng thuy canh tuin hoin.
Bang 2. Anh hudng ciia loai dung djch dinh dudng ddn chidu cao rau mudng trdng trii vu bing cdng ngh^
thiiy canh tuin hoin (cm) Lo^iidung
dich DD CTl (d/c) CT2 CT3
Sau khi dua ten h§ thdng thuy canh 7
ngiy 25.6 25,5 28,8
14 ngiy 24,7 26,8 29,5
21 ngiy 23.7 26.0 28.6
28 ngiy 22,8 26,5 28,5
35 ngiy 23,6 27.4 30,7
43 ngiy 24,7 25,3 36,2
50 ngiy 25,7 24.8 36.5
57 ngiy 20.7 22.0 30.4 Ghi chii: Chieu cao cua rau mudng dupe do tai thdi diem mdi lua hii
Sd lidu d bang 2 cho thay d CT3, cay rau mudng sinh trudng tdt, chidu cao ciy dat 28,5- 36,5 cm - Cao hon CT 1 vi CT 2 d tit ca cic dot theo ddi. Cu tiid, sau khi dua Idn he thdng thuy canh 73 ngiy, trong khi rau mudng d ddi chiing (cdng thiic 1) cao 23,1 cm thi a cdng thiic 3 rau mudng cao 30,7 cm, tuong ling vdi cao hon 32,9% so vdi ddi chiing. Nhu vay, ddi vdi rau mudng, dung dich d cdng thiic 3 tdt hon ddi chiing.
2. Anh huong ciia l o ^ dtmg dtch dinh dudng ddn nang suit cic l o ^ rau trdng trii vvi bing cdng ngh$
thuy canh tuin hoin
Kdt qui thi nghidm d bang 3 cho thay:
- Vd chi tidu khdi lugng cay: Khdi lugng cay ciia c i 3 loai rau d cdng thiic 2 tuong duong cdng thiic ddi chiing (cdng thiic 1).
- Vd chi tidu ning suit: Kdt qua xii li thdng ke cho thiy, c i 3 loai rau l i x i lich, cai xanh vi can tiy deu cd ning suit d cdng thiic 2 tuong duong cdng thiic ddi chiing (cdng thiic 1) va cao hon ning suat d cdng thiic 2 mpt cich chic chin. Cu thd, ning suit cua 2 cdng thiic niy nhu sau: x i lich dat 35,28 ta/1000 m^i cii xanh dat 38,94 ta/1000 m^; cin tiy dat 46,06 ta/1000 m^
Bang 3. Anh hudng ciia loai dung djch dinh dudng ddn khdi lugng ciy vi ning suit mdt sd loai rau trdng trii viJi bing cdng ngh^ thuy canh tuin hoin
Nam TN
2007 Loai dung dich dinh duong CTl (d/c)
CT2 CT3 Ftest CV.%
Khdi lu(?ng ciy (g/ciy) X i l i c h
55,3 57,8 52.5
Cai xanh 59.5 58.7 49,5
Cin tiy 71,5 71,7 58,2
-
Ning suit li thuydt (ta/lOCO m') X i l i c h
39,82 41,62 37,80
Cai xanh 42,84 42.26 35.64
Cin tiy 51,48 51,62 49,10
Ning suit thuc thu (ta/1000 m^
X i l i c h 35,46 a 35,28 a 30,16 b 2 1 , 2 1 "
1,2 Cai xanh
38,52 a 38,94 a 31.06 b 54,17**
1,1
Can tiy 46,25 a 46,06 a 43,53 b 31,9**
1,2 NONG NGHIEP VA PHAT TRIEN NONG THON - KY 2 - THANG 5/2012 39
KHOA HQC C 6 N 0 NGHE
Bang 4. Anh huong cua lo?i dung djch dinh duflng din ning su& rau muing tiing trii vu bing cdng nghi thuy canh tudn hoin
Thoi gian nghiin
cuu
10/07- 3/08
Thdi gian nghien
cuu
10/07- 3/08
Loai dung dich DD
CTl (d/c) CT2 CT3 Ftest CV.*
Loai dung dich DD
CTl (d/c) CT2 CT3 Ftest CV,96
Ilia 1 Khdi Iui?ng (g/ciy)
82.6 110.6 144,8
NSthuc thu {ta/1000
m'^
28,75 c 37,78 b 48,58 a
...
0,9 lira 5 Khdi luong (g/cay)
89.6 126.5 192,1
-
NSthuc thu (t9/1000
32,78 c 34,33 b 62,84 a
•**
1,0
lira 2 Khdi lugng (g/ciy)
84,6 116.5 175,2
NSthi,rc thu (t?/1000
m") 29,46 c 35,56 b 61,25 a
...
1,0 lua 6 Khdi luong (g/ciy)
88,7 136,5 200,5
NSthvc thu (t?/1000
m^
28.75 c 39.34 b 63,52 a
...
0.9Ilia 3
Khdi
luijng (g/ciy)87,5 126,2 182,3
NSthi.rc thu (ta/1000
m^
30,78 c 36,33 b 62,04 a
...
1,0 Ilia 7 Khdi lugng (g/ciy)
88.5 130.8 171,7
- -
NSthuc thu (ta/1000
m^
29,46 c 38,58 b 50,06 a
...
1,2
Ilia 4 Khdi lugng (g/ciy)
82,7 136,5 193.9
NSthuc thu (ta/1000
m^
27,79 c 38.38 b 62,58 a
***
1,1 Ilia 8 Khdi luong (g/ciy)
82.0 123,6 164,8
- -
NSthuc thu (ta/1000
m^
25,73c 30,78b 44,56a
...
1,4
Kdt qua nghidn ciiu d bang 4 cho thay; 6 cdng
thiic 3, ning suit rau mudng d tit ca cic liia hii dat 44,56 ddn 63,52 ta/1000 m^ Trong khi dd, ning suit rau mudng cua cic liia hii d ddi chung chi d^it td 30,78 ddn 39,34 ta/1000 m=^. Kdt qua xir li thdng kd cho thay, ning suit rau mudng d cac lira hii ddu cao hon cdng thiic ddi chiing (cdng thiic 1) vi cao hon cdng thiic 2 mgt cich chic chin.
Nhung kdt qua niy hoin toin phii hgp vdi nhiing nghidn ciiu trudc cua cic tic gia: Nguyen Thj Ddn, 1998 [3]; Nguyen Khic Thii Son vi Nguyen Quang Thach, 1996 [51; Vu Quang Sing, 2000 [4].
Ket qua tii nhimg nghidn ciiu niy ddu khing djnh ring chiing ta cd thd chii dgng pha chd dung djch dinh dudng dd trdng ciy thiiy canh khdng kem gi va cd gia thanh thap hon so vdi dung dich nhip ngoai.
3. Anh hudng cua lo^i dung djch dinh dudng ddn ham lugng nitrat vi mdt sd m^t sd kim lo^i ning trong xi lidi, cii xanh trdng trii vu bing cdng ngh$ ttiiiy canh tuin hoin
Kdt qua phin tich d bang 5 cho thay, trdn cic loai rau d cic cong thiic dung dich dinh dirdng him
lugng nitrat, chi va cadimi ddu dudi ngudng tieu chuan cho phep rit nhidu. Du lugng nitiiit (NO3) trong xa lich tir 243- 343 mg/kg; trong cai xanh tii 285- 342 mg/kg - Bing 1/5 gidi hgn tdi da cho phep.
Him lugng Pb va Cd trong cac lo^i rau thuong pham cung rit thip: ti-ong rau xa lich, Pb bi 0,028- 0,053 mg/kg; Cd tii 0,005- 0.009 mg/kg; tiong rau cai xanh, Pb tii 0.045- 0,062 mg/kg; Cd tir 0.004- 0,008 mg/kg. Ca chi vi cadimi ddu dudi ngudng cho phep rit nhidu (ngudng cho phep cua chi li 1,0; cadimi li 0,1 vdi xi lich vi 0,2 vdi cai xanh mg/1 kg san phim tuoi). Didu niy, ciing phu hgp vdi nhiing kdt luin cua Pham Nggc Son (2006) nghidn ciiu ung dung ki that thiiy canh va khi canh trong san xuit rau cai xanh, xa lich d Hai Phong di kdt luin: Trdng ciy bing ki thuat thuy canh, khi canh cho ning suit cao va san pham an toan [6]. Nim 2000, Vd Kun Oanh, Nguydn Quang Thach va Cao Thi Thiiy nghidn ciiu anh hudng ciia lupng bdn, each bdn, mat do trdng ddn sa sinh trudng, phit tridn va tich luy NO3 ciia ciy cai nggt ti-dng ti-ong dung djch di cho thiy, d tat ca cac cdng thiic thi nghidm him lugng NO3 ddu dudi miic cho phdp cua Td chuc Y td TTid gidi (WHO) [1].
40 NONG NGHllP VA PHAT TRIEN N 6 N G THON - K i 2 - THANG 5/2012
KHOA HQC C 6 N 0 N 6 H |
Bang 5. Anh hudng cua dung dich dinh dudng ddn h i m lugng nitrat, chi, catmi trong x i lich vi cii xanh trdng trii vu bing cdng ngh^ thiiy canh tuin hoin
Loai rau
Xilich
Rau cai xanh
Cdng thiic dung dich
CTKPHNNI) CT2(VRQ1) CT3(VRQ2) CT4 (VRQ3) CT1(DHNNI) CT2(VRQ1) CT3(VRQ2) CT4 (VRQ3)
N O , (mg/kg tuoi) Trong rau
292 343 268 243 323 285 286 342
Gidi han cho ph6p
(TCVN)
1500
1500
Pb (mg/kg tuoi) Trong rau
0,051 0,053 0.028 0,044 0,058 0,048 0,045 0,062
Gidi han cho ph6p (TCVN)
1,0
1,0
Cd (mg/kg tuoi) Trong rau
0.007 0.005 0.009 0.008 0,008 0,005 0,004 0,008
iff
0,1
0.2
IV. KET LUAN VA BE NGHI
1- Dung dich dinh dudng cua Vidn Sinh hpc Nong nghidp (Trudng Dai hoc Ndng nghidp H i Ndi), VRQl cua Vidn Nghidn ciiu Rau Qua phii hpp cho san xuat rau xa lich, rau cai xanh v i rau cin tiy. Sau trong 20 ngay trdn cic dung dich nay, ning suit xa lach dat hiong ling l i 35,46 v i 35,28 ta/lOOO m^; cai xanh hiong iimg dat 38,52 v i 38,94 ta/lOOO m^ Sau trong 30 ngiy trdn cac dung dich nay, ning suit can tiy tirong ling dat 46,25 va 46,06 ta/lOOO m^. Dung dich dmh dudng VRQ2 phii hgp cho sin xuat, ning suat rau mudng d cac liia hii dat tir 44,56 ddn 63,52 ta/1000 m l
2- Ca 3 loai dung dich dinh dudng ddu dam bao ham lugng nitrat, chi, cadimi trong rau thap hon nhidu so vdi ngudng cho phep. Him lugng nitrat ti-ong x i lich tii 243 ddn 343 mg/100 kg tuoi, ti-ong cai xanh tii 285 ddn 342 mg/100 kg tuoi. Him lugng chi ti-ong x i lach tii 0,028 ddn 0,053 mg/100 kg tuoi, trong cai xanh tii 0,045 ddn 0,062 mg/100 kg tuoi.
Him lugng catmi trong x i lich tir 0,005 ddn 0,009 mg/100 kg hioi, ti-ong cai xanh tii 0,004 ddn 0,008 mg/100 kg tuoi.
3- Tidp tuc nghidn cuu tiidm ndi dung dung dich dinh dudng, didu chinh pH v i EC cua dung dich dinh dudng cho tiing giai doan sinh trudng, phat tridn cua toig loai rau.
TAlLJ$UTtlAMKHi^O
1. Hoang Minh Chiu, 2010. Nghiin cihi xac dinh gidng vi gii thd thich hop nhhn ^ng ning suit va chit luong xi lich, cai xanh, cin tiy trSng bing cdng ngh$ thuy canh tuan hoin (NFT) trong nha ludi. Luin vin Thac si Khoa hoc Ndng nghiep, Trudng Dai hgc Ndng nghidp H i Ndi.
2. Nguydn Thi Dan, 1998. Kdt q u i khio nghiem dung dich tiiiiy canh Thing Long ddi vdi mdt sd loai rau i n li, i n qua v i hoa. Tap chi Khoa hpc Ky thuat Rau, Hoa, Qui, (3), ti". 17-19.
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N 6 N G NGHllP VA PHAT TRIEN NONG THON - KY 2 - THANG 5/2012 41
KHOA HQC C 6 N 0 NGHE
TO FIND OUTTHE BEST HYDROPONIC NUTRIENT SOLUTION FOR SOME TYPES OF LEAF VEGETABLES
Nguyen Minh Chung. Tran Khac Tlii, Nguyen Khac Tliai Son, Hoang Minh Chau, Nguyen Du An Summary
Originating from a desire to reduce production costs, and find out suitable types of hydroponic nutrient solution for different types of leaf vegetables, a study was conducted on 4 types of vegetables including lettuce, Chinese cabbage, celery and water morning glory with three formula of nutrient solution. Two solutions by Hanoi Fruit and Vegetable Research Institute was studied in comparison with the control solution by the Institute of Agricultural Biology (Hanoi University of Agriculture). The results show that the nutrient solution by the Institute of Agricultural Biology (Hanoi University of Agriculture), nutnent solution VRQl by Hanoi Fruit and Vegetable Research Institute are suitable for lettuce, Chinese cabbage and celery.
After 20 days grown in this solution, tiie yield of lettuce reached 35.46 and 35.28 quintal/1000 m*
respectively; the yield of Chinese cabbage reached 38.52 and 38.94 quintal/1000 m^ respectively. After 30 days grown in this solution, the yield of celery reached 46.25 and 46.06 quintal/1000 m^ respectively.
Nutrient solution VRQ2 is suitable for water moming glory, the yield of different picking times ranged from 44.56 to 63.52 qiiintal/1000 ml All three nutrient solutions ensured the proportion of nitiates, lead and cadmium in vegetables is much lower than the permitted proportion. The proportion of nitrate in fresh lethice is from 243 to 343 mg/100 kg, in fresh Chinese cabbage is from 285 to 342 mg/100 kg. TTie proportion of lead in fresh lettuce is from 0.028 to 0.053 mg/100 kg, in fresh Chinese cabbage is from 0.045 to 0.062 mg/100 kg. The proportion of cadmium in fresh lettuce is from 0.005 to 0.009 mg/100 kg and in fresh Chinese cabbage is from 0.004 to 0.008 mg/100 kg.
Key words: Lettuce, Chinese cabbage, celery, liquid, nutrition, hydroponics.
Ngudi phan b i ^ : TS. Bui Huy Hidn
42 N 6 N G NGHIEP V A PHAT TRIEN N 6 N G T H 6 N - KY 2 - THANG 5/2012
