thuy canh w

7/31/2019 THUY CANH W

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B GIO DC V O TO

TRNG H K THUT CNG NGH TP.HCM

KHOA MI TRNG V CNG NGH SINH HC

SEMINAR

K THUT THY CANH

NNGCAO CHT LNG CY

TRNGGVHD: Thy Bi Vn Th Vinh

NHM SVTH: 1. Trng Khnh Linh

2. Dng Hynh Anh

3. Nguyn Th Ngc Trn

4. Nguyn Th Hai Thng

5. Hynh Th Thun

6. L Th Kim Loan

-2007-

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LI GII THIU

Mi mt ngy tri qua , cuc sng ca con ngi cng theo m pht

trin . V c nh th , dng nh cuc sng dn dn tr nn vt khi tmkim sot ca h .

Phi , c mt cuc sng sung tc , y tht s l iu m aicng m c nhng tri li chng ta dn phi nh i ci m con ngicn nht : sc khe .

Nhng cng khng th ph nhn rng bn cnh con ngi cng nghin cu ra rt nhiu phng thc va ci thin cuc sng va cth m bo an tan cho sc khe ca chng ta .

V mt trong nhng phng php c th sn xut ra rau sch mkhng hao tn qu nhiu nhn cng hay sc lc , chng ta cng c th tlm ti nh . Chnh l Thy Canh .

Nhm lm ti ny mong rng s gip cho cc bn cng nh mingi hiu bit thm phn no v cch thc trng trt ny .

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MC LC

Li gii thiu 2

Phn I : Tng quan v k thut thu canhI / Gii thiu 4II / Li ch ca vic nui trng thu canh ...7

Phn II : Cht dinh dng Mi trng nui trng thu canhI / Nhu cu - nhim v cht dinh dng 10II / Dung dch dinh dng ..13

Phn III : Cc yu t mi trng nhhng n s sinh trng v

pht trin ca cy trng thy canhI / nh hng ca s thong kh.............................................................19II / nh hng ca s ngp ng..............................................................19III / nh hng ca nhit ....................................................................20IV / nh hng ca nh sng..................................................................20V / nh hng ca nng v t l nguyn t khong............................20VI / nh hng ca gi th......................................................................20

Phn IV : Cc loi hnh thu canhI / H thng thu canh khng hi lu ..20

II / H thng thu canh hi lu .20III / H thng c s dng gi th rn ..20IV / H thng kh canh ..21V / K thut thu canh mng mng dinh dng NFT ..21

Phn V : Quy trnh k thut thu canhI / H thng thy canh ca trung tm pht trin rau Chu ..23II / Qui trnh thy canh ..24III / Mt s im cn lu khi trng thy canh vo ma ma min Nam .24IV / So snh gia cy trng cn t v thy canh 25V / Mt v d v qui trnh k thut thy canh 26

Nhn xt chung .29

Ti liu tham kho 30

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PHN ITNG QUAN THY CANH HC

(hydroponics)I / GII THIU:

1. K thut thy canh l g?

Thy canh l k thut trng cy khng dng t m trng trc tipvo mi trng dinh dng hoc gi th m khng phi l t. cc gi thc th l ct , tru, v x da , than bn, vermiculite perlite..

K thut thy canh l mt trong nhng ngh lm vn hin i. chnla mi trng t nhin cn thit cho cy pht trin l chn s dngnghng cht thch hp cho s sinh trng v pht trin ca cy, trnhc s pht trin ca cn trng, c di v cc bnh tt t t.

M hnh thy canh

2. S lc lch s nghin cu:

2.1. Ngoi nc:

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K thut thy canh c t lu.theo nhng t ng ghi chp t chtng hnh ca ngi ai cp trong vi nm trc cng nguyn, m t lis trng cy trong nc.

S nghin cu ca nhng nin i gn y cho thy vn treo

babilon v vn ni kashimir v ti aztec indians ca Mehico cng cnnhiu ni trng cy trn va h trong nhng h cn. hin ti vn cn nhiub trng cy c tm thy gn thnh ph Mehico.

1699 , John Woodward ( Ngi Anh ) th nghim trng cy trongnc c cha cc loi t khc nhau.

- Nhng nm 60 ca th k 19 Sachs &Knop (c) sn xut racc dung dch nui cy

- Trong nhng nm 30 ca th k 20 ts.W.F.Gericke (California) ph bin rng ri thu canh nc m. nhng nng tri thy canh di ng cung cp thc phm rau ti cho lnh m trong sut thi gian chintranh qun s ti Nam Thi Bnh Dng.

Trong s trong tri ln nht th trng cho mc ch kinh doanhnh hoa Cm Chng, Layon, Cc

Ngoi ra cn c cc c s trng thy canh hoa , c, Thyin

a phn nc chu m la tinh trng thc phm phc v cho lngthc l ch yu: nam phi 400ha, h lan 3600ha

Nht Bn y nhanh k thut thy canh sn xut rau sch . anton thc phm l mt trong nhng vn m ngi nht quan tm, hln lo ngi thuc tr su, cc cht ph gia nng nghip . Hn na v dintch canh tc hp nn kiu trng thy canh ny li p ng nhanh nhu cucho tinh thn v i sng ngi Nht Bn.

2.2.

trong nc:Vic nui trng thy canh c bit n kh lu, nhng cha c

nghin cu c h thng v c ng dng trng cc loi cy cnh nhiuhn.

T 1993, gs, L nh Lng _ khoa sinh hc H quc gia H Niphi hp vi tng nghin cu v trin khai Hngkong tin hnh nghin

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cu ton din cc kha cnh khoa hc x hi cho vic chuyn giao cngngh v pht trin thy canh Vit Nam

n thng 10/1995 mng li nghin cu v trin khai c phttrin H Ni, Tp.Hcm , Cn o, s khoa hc cng ngh mt s tnh

thnh . Cng ty Gold Garden& Gino, nhm sinh vin i Hc Khoa Hc TNhin Tp. Hcm vi phng php thy canh vi loi rau xanh thng dng,ci xanh, ci ngt, x lchphn vin cng ngh sau thu hoch. Vin sinhhc nhit i cng nghin cu v sn xut. Ni dung ch yu l:

+Thit k v phi hp sn xut th cc vt liu dng trng thy canh.

+ Nghin cu trng cc loi cy khc nhau , cy truyn t nui cy mvo h thng thy canh trc khi a vo t mt s cy n qu kh trngtrc tip vo t.

+ Trin khai thy canh quy m gia nh, thnh th v nng thn.

+ Kt hp thy canh vi d n rau sch thnh ph.

Qu trnh v cc h thng trong vic nghin cu trng hoa ng sc theo quym thy canh

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H thng thy canh theo quy m nh

II / LI CH CA VIC NUI TRNG THY CANH :

1. Li ch ca vic nui trng thy canh :

Ngy nay thy canh c vai tr quan trng trong i sng hng ngyca chng ta. N to ra v s iu kin thun li t vic pht trin cy trngkhng tn din tch t canh tc, li th thu hoch sn phm cao trnh tnhtrng tht thu do cc iu kin khch quan ln ch quan, p ng c nhucu anh sch v sinh an ton thc phm ca con ngi trong thi k phttrin hin i

Tm li nhng u im ca k thut thy canh hin i:

1/ Khng cn t, ch cn khng gian t hp dng c cy trng, do vyc th trin khai nhng vng t nh hi o, vng ni xa xi, cng nh

ti gia nh trn sn thng , balcon

2/ Khng phi lm t, khng c c di , khng cn ti.

3/ Trng c nhiu v c th trng tri v.

4/ Khng phi s dng thuc tr su bnh v cc ha cht c hi khc.

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5/ Nng sut cao, v c th trng lin tc.

6/ Sn phm hon ton sch v ng nht, giu dinh dng v ti ngon.

7/ Khng tch ly cht c khng gy nhim mi trng.

8/ Khng i hi lao ng nng nhc, ngi gi , tr em u c th thamgia hiu qu.

Tuy nhin k thut thy canh cng c nhiu yu im:

1/ Ch trng c cy rau qu ngn ngy

2/ Gi thnh sn phm cn cao.

2. Thy canh vi vic sn xut rau sch :

Vic ng c thc phm do thuc tr suhay ha cht bo v thcvt chim t l cao. Tuy ng c khng khng gy ra ng c tc thinhng nh hng lu di c th gy ung th.

Cc thuc tr sau c hi ti vo rau vi nng gp 10-20 ln, ckhi 50 ln. Chnh v th m tnh trng rau sch s dng tr thnh minhu cu cp thit.

Vy th no l rau sch?

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nh ngha rau sch c rt nhiu kin khc nhau. Hin nay, VitNam cha c mt tiu chun no chnh xc cho rau sch ch c th xcnh c bng vic da vo gii hn cho php ca dung lng thuc trsu v thuc bo v thc vt ca FAO & WHO: rau sch l rau c dlng thuc bo v thc vt khng vt mc cho php d lng cc c

t vi sinh c hi ti sc kho con ngi mc ti thiu cho php .

Hin nay sn xut rau sch c tin hnh theo cc m hnh cngngh khc nhau : thy canh cch ly, nh li cch ly, canh tc hu c vsn xut trn ng rung.

Tuy nhin vi mi m hnh vn then cht vn l phn bn, ncti, quy trnh s dng nng dc v cc bin php nng hc khc nhau bo v thc vt .

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PHN IICHT DINH DNG - MI TRNG

NUI TRNG THU CANHI / Cht dinh dng : nhu cu - nhim v ca mt s cht v khongcht quan trng :

Nhng nguyn t cn thit cho s sinh trng v pht trin thch hpl O, H, C, S, Mg, Mn, Fe, Cu, Zn, Bo, Mo. Mt s nguyn t th ch cn vis lng rt t, tuy nhin mt trong s cc nguyn t c th tr thnhmt nhn t gii hn i vi s lnh mnh ca cy. Nhiu nguyn t ctm thy trong cc enzyme v co-enzyme, trong khi nhng cht khc thquan trng i vi s tch tr thc n. S thiu ht bt k mt nguyn tno u th hin ra vi nhng triu chng v c th ring, c th cho tabit l cy ang thiu loi nguyn t no.

Carbon v oxy c cung cp bi khng kh dng CO2. Kh CO2c xm nhp vo c th thc vt qua quang hp hay ha tan trongnc.1 . Cc nguyn t :a) Oxy (O2) :

O2 ng vai tr quan trng i v sinh trng v pht trin ca cy,do chc nng tham gia vo qu trnh h hp.

Chc nng sng c th b ngng li nu nh khng c qu trnh h

hp. khi hp th O2 qua r c th gim st nu nh r mc trong nckhng c thong kh, hoc gia lp ct m khng kh khng th voc.b) Hydro (H2) :

Cy hp th H2 hu ht l t nc, thng qua qu trnh thm thu r. N rt quan trng v cht bo v cacbohydrat u c thnh phn chnh lH, cng vi O v C. Tnh acid ca mi trng ph thuc vo lng ion H+,cn tnh kim ty thuc vo lng ion OH-.

2 . Nguyn t a lng:

Hin din vi phn nghn n vi phn trmBao gm: N:1-3%; K: 2-4%; Ca: 1-2%; Mg: 0.1-0.7%; S: 0.1-0.6%; P:0.1-0.5%

C th xp Cl, Na, Si vo nhm nguyn t a lng v chng c hmlng rt thay i ty thuc vo loi thc vta) Nit (N2) :

L thnh phn bt buc ca protit cht c trng cho s sng

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Cc hp cht Nit cn cung cp nng lng cho c th, tham giacu to ADP v ATP.

Nit cn l thnh phn ca nhiu Vit B1, B2, B6, PPng vai tr lnhm hot ng ca nhiu h enzyme y ha kh, trong c s to thnhadenine

Nit cn tc ng nhiu mt n s ng ha CO2, khi thiu Nitcng ng ha CO2 gim lm gim cng quang hp. Khi cung cpy Nit cho cy lm tng hp auxin tng ln. Nit cn nh hng ncc ch tiu ha keo ca cht sng nh a nc, nhtt nhhng n cng quang hp, h hp v cc qu trnh sinh l trao icht. Dng s dng ure, (NH4)2SO4, NH4NO3

Nu cy trng hp thu N2 vt qu nhu cu th than cy s mmmng v kh hnh thnh hoa. Tuy nhin, nu khng cung cp lng cnthit, cy s b cng do tha xenlulo v lignin thnh t bo

Nit l nguyn t a lng duy nht m cy trng c th hp th

c dng anion v cationKhi thiu Nit th than l, b r km pht trin, l c mu xanh nht,phin l mng, nh hng n quang hp nn nng sut gim r rt.b) Photpho(P) :

P l thnh phn quan trng trong s sinh trng, P cn thit cho sphn chia t bo, s to hoa v tri, s pht trin ca r. P c lien quann s tng hp ng, tinh bt v P l thnh phn ca cc hp cht caonng tham gia vo cc qu trnh phn gii hay tng hp cc cht hu ctrong t bo

Khi thiu P cy c biu hin r rt v hnh thi bn ngoi, l nng

sut gimS thiu P thng i i vi s thiu N2 v c triu chng gn tngt nhau v P lin h n s bin dng N2 .c) Kali (K) :

K lm gia tng n s quang hp v thc y s vn chuyn gluxitt phin l vo cc c quan. Kali cn tc ng r rt n trao i protit, lipit,n qu trnh hnh thnh cc vitamin .

K rt cn thit cho s sinh trng v c vai tr quan trng trong vicduy tr cht lng qu .

Tuy nhin, khi tng hm lng K th li gy nh hng bt li cho

vic hp th Mg .K gip cho vic tng tnh chng chu ca cy vi nhit thp, khhn v bnh .

Khi thiu K th s tch t ammoniac cao, gy c hi cho cy .d) Canxi (Ca)

Canxi l thnh phn mui pectat ca t bo (pectat canxium) c nhhng trn tnh thm ca mng. Trong t bo Ca hin din khng bo,m gi l gi nhiu Ca hn l non .

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Khi nng Ca cao trong mi trng th Fe b kt ta cho nn cccht ny gim hoc khng di chuyn vo trong t bo, kt qu l b vng ( vFe l thnh phn cu to cc dip lc t). Ca cn l cht hot ha ca vienzyme nht l ATPase .

Khi thiu Ca c bit l trong mi trng thy canh th r s b nhy

nha a n s hp thu cht dinh dng b tr ngi, cy ngng sinhtrng pht trin v cht. Biu hin thiu ngn chi l non thng bxon, l b tua chy ba l, than cung hao gy, sinh trng b chtCa2+ cn l cht i khng ca ion K+.e) Magi(Mg) :

L thnh phn cu trc ca dip lc t, c tc dng su sc v nhiumt n qu trnh quang hp, ph tr cho nhiu enzyme c bit ATPaselien quan trong bin dng carbonhydrat, s tng hp acid nucleic, s btcp ca ATP vi cc cht phn ng .

Khi thiu Mg l b vng, quang hp km dn n nng sut gim .

3 . Nguyn t vi lng :Cc nguyn t vi lng c vai tr quan trng trong i sng thc vt.

Hm lng khong mt phn nghn n mt trm phn nghn. Cc nguynt vi lng tham gia vo qu trnh y ha kh, quang hp, trao i N vgluxit ca thc vt, tham gia vo cc trung tm hot tnh ca enzyme vvitamin, tng tnh chng chu ca c th thc vt i vi cc iu kin mitrng bt li. S thiu ht cc nguyn t vi lng c th gy ra nhiubnh v cht

Cc nguyn t vi lng : Cu, Bo, Zn, Mo

a) Km (Zn) :Tham gia trong qu trnh tg hp auxin, v Zn c lien quan n hmlng tryptophan aminoaxid, tin than ca qu trnh sinh tng hp NAAZn cn l cht hot ha ca nhiu enzyme dehydogenaza, c th c vai trtrong s tng hp protein .

Zn c tc dng phi hp vi nhm GA3, Zn c lien quan n sinhtng hp vitamin nhm B1, B2, B6, B12 .

Zn cn thc y s vn chuyn cc sn phm quang hp t l xungcc c quan d tr, tng kh nng gi nc, ngm nc ca m .

Khi thiu Zn th cng tng hp trypthophan t undol v xin b

km hm nn r khng to c hoc km pht trin, l b bc mu sc tb hy hoi, l km pht trin dng l khng bnh thng .b) Lu hunh (S) :

Gi vai tr m trong t bo .S l thnh phn cu trc ca cystein, methyonin, to cu ni S-S to

cu trc bc 3 ca protein .

c)St (Fe):

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C vai tr quan trng trong phn ng oxy ha kh, l nhn ca poocphyrin, Fe tham d trong chuyn in t quang hp .

Fe cn xc tc s kh CO2 ca OAA ( oxaloacetic acid), succinicacid. Fe ng vai tr kt hp gia enzyme v i cht enzyme d dnghot ng .

S thiu ht nhanh chng biu hin trn l v s ngn chn ssinh trng v pht trin. D thiu ht Fe thng dn n bnh vng ltrm trng, gim lng clorophin l. Fe khng hoy ng mnh trong cyv tc ng thiu ny s biu hin mu vng trn nhng l non .

Lng Fe gim trong mi trng dung dch dinh dng kh nhanhso vi nhng nguyn t khc trong mi trng do:

- Qa trnh oxy ha Fe bi tia UV khi m dung dch dinh dng cungcp cho cy di dng cc tia phun sng

- PH ca dung dch dinh dng vt qu 6.5- S hp thu ca cy trng cho s sinh trng v pht trin

- Tr thnh dng khng tan bi mt s cu phn khc trong mitrng- Thiu Fe thng b vng hon ton v b chy sm ngn, mp l.- Nu mi trng nhiu Zn, Cu, P dn n thiu Fe- Nu mi trng thiu Mg, Ca , K cng dn n thiu Fe

d) ng (Cu) :Cng l thnh phn cu to ca nhiu enzyme xc tc cc phn ng

oxy ha kh, can thip vo cc phn ng oxy ha cn O2 phn tthiu Cu l km pht trin, l mu xanh m, nu thiu nhiu dn n chtmt phn ca l .

Cu cn c tc dng ngn nga s pht trin ca vi sinh vt trong mitrng dinh dng nc .e) Mangan( Mn) :

nh hng ca Mn i vi cy trng kh ging Fef) Silic (Si) :

Si c 2 hiu qu ng k sau:- Chng li s tn cng ca cn trng v bnh tt- Chng li tc dng ca kim loi

II . Dung dch dinh dng :

1. S pha ch :Trong thy canh tt c cc cht cn thit cung cp cho cy u cs dng di dng cc mui khong v c c ha tan trong dung mi lnc .

Nu s dng cc mi trng dinh dng vi dng nc th phi nmr nguyn tc pha ch chng khng b kt ta lm mt tc dng ca hacht .

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S thnh cng hay tht bi ca vic trng thy canh u ph thucvo vic x l cht dinh dng, iu ny c th t c ty thuc vo PH, nhit v dn in ca mi trng .

2 . PH :

Trong mi trng dinh dng, PH rt quan trng cho s sinhtrng v pht trin ca cy .

PH c tnh da trn mc hot ng ca cc nguyn t khcnhau vi cy trng .

Vic iu khin PH ca dung dch rt quan trng ngn chn pHtng ln qu cao s gy ra tnh trng kt ta ca Ca3(PO4)2, gy ngt ngdn dung dch v bm quanh b r ca cy. ngn chn pH tng cao sdng H3PO4, HNO3 hoc cng c th s dng NH3 .

Nu pH xung di 5.5, KOH hay mt vi cht thch hp khc c ththm vo dung dch tng pH ln .

S thay i pH trong dung dch dinh dng thng xy ra khnhanh, ph thuc vo ln ca h thng r v th tch dinh dng camt cy .

Gi th c s dng cng lu th nhng nhn t hu c ng litrong cng nhiu v cn nhiu s iu chnh cn thit t c pHnh mong mun .

Trong thy canh a s cc cy trng thch hp vi mi trng hiacid n gn trung tnh, pH ti u t 5.8-6.5 .

Trong nui trng thy canh, pH c cn bng bi hot ng cacy. Nu pH tng khi cy s thi ra cc mui acid vo mi trng, c

th l nguyn nhn lm cht c trong mi trng tng ln v lm hn chs dn nc. nu pH gim xung th cy s thi ra cc thnh phn ionbaz, c th lm gii hn vic hp thu cc mui gc acid, nn r cy khngcn thit hp thu .

Nhn chung pH ca mi trng nn kim tra thng xuyn khi trngthy canh c th 2-3 ln/ tun .

Lu :- S thay i pH ca mi trng dinh dng trong thy canh c th do

cc vi sinh vt gy ra .-

PH ni bo khng ch ph thuc vo mi trng chung quanh m visinh vt c th kim sot c mt phn nh tit cc ion .- PH trong t bo khng ging nh mi trng ngoi, ngay trong ni t

bo pH cng khng ng nht .- Nhng th nghim nghin cu gn y cho thy:

+ PH ca t bo do pH ca mi trng quyt nh .+ PH tc ng n s vn chuyn cc cht dinh dng qua mng t

bo .

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3 . Nhit :Dao ng v nhit trong mi trng dinh dng thy canh

khng ch tc ng n pH m cn nh hng n ha tan ca ccdng cht .

Nhit ca nc thch hp ha tan cc cht khong l 20-22oC.

4 . B sung cht dinh dng :Hai yu t cn c xem xt nghin cu mt dung dch b sung :- Thnh phn dung dch .- Nng d dung dch .Trong thi gian sinh trng v pht trin ca cy , cy s s dng

cc cht dinh dng theo nhu cu i hi ca chng .i vi loi cy c thi gian sinh tng tng i di th vic b sung dinhdng l rt cn thit .

Trong nghin cu ngi ta c th da vo gi tr ca dn in

(EC : electro\ conductivity) ; s phn hu cc mui khong (TDS : Toatldissolved salts ) hoc nhn t hon tan (CF : conductivity factor ) ca ccmy o iu chnh b sung cht dinh dng vo mi trng nui trngthu canh .

dn in (electro conductivity EC ) hay yu t dn in(conductivity factor CF ) c th c biu din nh millisiemen (mS) hayphn triu (ppm) .

Electro conductivity ch tnh cht ca mt mi trng c thchuyn ti i dng in . dn in ca mt dung dch l s dn ca

dung dch ny c o gia nhng in cc c b mt l 1 cm2

khongcch 1 cm , n v tnh l mS/cm ; hoc c th hin n v ppm (partsper million) i vi nhng my o TDS (total dissolved salt ) .

Ch s EC ch din t tng nng ion ho tan trong dung dch , chkhng th hin c nng ca tng thnh phn ring bit .

Trong sut qu trnh tng trng , cy hp thu khong cht m chngcn , do vy duy tr EC mt mc n nh l rt quan trng .

Nu dung dch c ch s EC cao th s hp thu nc ca cy din ranhanh hn s hp thu khong cht , hu qu l nng dung dch s rtcao v gy c cho cy . Khi ta phi b sung thm nc vo mi

trng .Ngc li , nu EC thp , cy s hp thu khong cht nhanh hn hpthu nc v khi ta phi b sung thm khong cht vo dung dch .

Mt s gii hn EC v TDS i vi mt s loi cy trng :

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EC (ms/cm) TDS (ppm)Cm chng 2.4 5.0 1400 2450

a lan 0.6 1.5 420 560Hoa hng 1.5 2.4 1050 1750

C chua 2.4 5.0 1400 3500X lch 0.6 1.5 280 1260

X lch xoong 0.6 1.5 280 1260Cy chui 1.5 2.4 1260 1540Cy da 2.4 5.0 1400 1680Du ty 1.5 2.4 1260 1540

t 1.5 2.4 1260 1540

DO ( dissolved oxigen ) :DO l n v dng o hm lng oxigen ho tan trong mt lt

nc , n v (mg/l) . o DO bit c thong kh ca mi trngdinh dng . Ch s DO cao thun li cho hot ng h hp v bin dngca h r .

DO ph thuc vo nhit , p sut v mn ca dung dch .

4.1 . Thnh phn dung dch (t l cht dinh dng khong ) :c xc nh bi cc cht m cy i hi . Vic phn tch phin l

da trn nng dinh dng khong c trong m l , v l l ni xy ra qutrnh quang hp v do lng enzym trong m l cao nht . Nng dinhdng khong trung bnh trong ton cy thng t hn nng trong l , vvy mt dung dch b sung cn bn phi da trn nng cc cht ctrong m l m chng s cung cp cho thn , ht v tri .

Cc cy cn nh d dng thiu ht cht dinh dng nhng him khino to ra cht c Chnh v vy , tc gi s dng dung dch ban u cnng cao . Tuy nhin , dung dch b sung c y cht dinh dngny ch thch hp cho cy giai on u (thch hp cho s to l saugiai on ny mm ) , v n s tr nn qu m c khi thn v l pht

trin . Cho nn tc gi thay i thnh phn ca dung dch b sung theotng thi k pht tin ca cy nhm ngn cn s tch lu dinh dngkhong trong dung dch . Chu trnh sng c chia thnh 3 giai on sauy (tng ng vi 3 loi dung dch b sung ) :

+ Giai on u ca s pht trin cy : thng l m t (startersolution) .

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+ Giai on pht trin : trong sut giai on pht trin thn v l phttrin nh nhau (vegetative refill solution) .

+ Giai on trng thnh : giai on trng thnh , l pht trin tithiu , cht dinh dng c huy ng vo trong ht v tri (seed refillsolution) .

S pht trin ca r xy ra ch yu giai on u v t quan trnghn giai on sau . Trong sut giai on trng thnh , r rt t pht trinv gn nh ngng hn .

4.2 / Nng ion trong dung dch :B sung c xc nh bi t l thot hi nc . S thot hi nc

quyt nh t l tiu th nc , s pht trin quyt nh t l tiu th chtdinh dng khong (s vn chuyn dinh dng khong t dung dch sangcy) . c lng s thot hi nc i vi s pht trin ca cy trong mitrng thu canh l 300 400 kg (litres) nc/ 1kg sinh khi kh . T l

chnh xc tu thuc vo m khng kh , m khi thp s lm tng sthot hi nc nhng khng tng s pht trin . Lng CO2 cao lm ngkhu v tng qu trnh quang hp , chnh v vy s thot hi nc n mtt l no s gim xung cn 200kg nc /1kg sinh khi kh .

Hiu bit v t l ny s rt c li trong vic quyt nh nng tng ng cho dung dch b sung . Tng nng ion c th c duy trbng cch iu chnh tnh dn in ca dung dch . Nu tnh dn in giatng , cn lm long dung dch b sung , nhng thnh phn cht dinhdng vn phi gi nguyn . Tnh dn in khng thay i nhanh cho nnch cn theo di vi ln trong tun .

4.3 .S chuyn vn ca dinh dng khong trong dung dch:Cc dinh dng khong thit yu c th c t theo 3 nhm sau

y da trn cch m chng b loi ra khi mi trng dinh dng (do cyb hp th) :

+ Nhm 1 : NO3, NH4 , P , K , Mn cc cht ny c hp thu mtcch ch ng nh r v b loi ra khi mi trng trong vi gi .

+ Nhm 2 : Mg , S , Fe , Zn , Cu , Mo , C cc cht ny c hp thu mc trung bnh v b loi khi mi trng nhanh hn nc .

+ Nhm 3 : Ca, B , cc cht ny c hp th mt cch th ng v

thng tch lu trong dung dch .Mt trong nhng kh khn trong vic theo di v iu chnh tng loiion l nng nhm 1 phi c gi mc thp nht nhm ngn cn stch lu cht c trong m thc vt . Tuy nhin , nng thp th rt khtheo di v iu chnh .

Nu nng cht dinh dng cao th iu ny cho bit l cy cnthm nc , do nc c thm vo l cn thit (nc c thm vobi hot ng ca cy ) .

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Khi nng cht dinh dng gim hn mc cho php th2i cay cnb sung dng cht nhiu hn nc .

iu cn ch l vic b sung mui khong hay nc cn ph thucvo ma v gieo trng . Vo nhng thng ma nhiu , t nng th b sungnc vo l t cn thit , v nhu cu nc cn thit cho s quang hp v

lng nc bc hi khng quan trng .Nu ch b sung nc m khng ch n b sung khong cht th

s nh hng n cht lng sn phm c th lm gim hng v ca rauqu . Trong thc t vic trng thu canh c cho thy iu trn khi trngcc loi rau n l nh : ci x lch , ci ngt , rau cn ty

Trong a s cc loi cy th nng tng cng ca cht dinh dngtrong khong t 500ppm - 2000ppm khng lm nh hng n p sutthm thu ca t bo . Tuy nhin mt s loi nh c chua , du ty cnnng mi trng dinh dng cao khong 3500ppm , hoc nng dinhdng c gi tr thp nh ci x lch xoong v gi tr trung bnh nh da

chut .Tu thuc vo giai on tng trng v pht trin ca cy , cho nnvic thm vo dung dch b sung theo mt tn s nht nh l iu khngcn thit . Cc cht dinh dng c hp thu nhanh chng s d dngc bin i trong m thc vt c ngha l cy c kh nng d tr chtdinh dng trong , r , thn , l v s nhanh chng bin i cho nhu cucn thit ca cy .

Cy s nhanh chng ly i vi loi khong thng dng trong khi litch lu cc cht khc . Cho nn nng ca N, P , K , trong dung dch cth mc thp (0.1mM hoc vi ppm) bi v cc cht ny c hp thu

vo cy . Vic duy tr dinh dng khong nng cao trong dung dch cth dn n tnh trng mt cn bng dinh dng do cy hp thu cccht qu nhiu .

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PHN IIICC YU T MI TRNG NH

HNG N S SINH TRNG VPHT TRIN CA CY TRNG THUCANH

I / nh hng ca s thong kh n s ht cht dinh dng :Ngun O2 trong nc l do O2 khuch tn t khng kh (nh gi) s

chuyn ng ca nc . Tuy nhin lng O2 trong nc lun khng cao ,O2 thng b mt do nhiu nguyn nhn :

+ Do to , ng vt ph du h hp .

+ Do qu trnh oxy ho cc cht hu c v v s trong nc .+ Ngun O2 do to quang hp thi ra l n nh v quan trng nht

cho nc . Trong nc sinh vt ly O2 kh nhng thi CO2 rt d dng .Mi trng bo ho O2 l mt trong nhng s kin quan trng nht

nh hng n s sinh trng v pht trin ca vi sinh vt . Khi tha O 2 ,gy ra tc hi cho tt c cc sinh vt . Cc sn phm trao i cht (axitamin) trong trng thi ch tha oxy c th tham gia phn ng to cc chtc cho c th nh H2O2 ...

Cc nh nghin cu thy s ht cc cht khong t mc caonht mi trng c nng O2 t 2 3% . Khi nng O2 di 2% tc

ht khong gim . Nhng nu tng nng O2 t 3 100% th tc khng thay i .Ngoi ra nh hng ca nng CO2 , N2 , H2S v pH mi trng .

S tch lu N2, H2S v nhiu kh khc trong nc gy c ch hot ng htkhong ca h r .

II / nh hng ca s ngp ng i vi h r :S thiu O2 trong vng r xy ra khi t thot nc km sau cn

ma hoc sau khi ti gy gim tng trng v gim nng sut cy trncn .

Mc d mi thc vt bc cao cn c nc t do , nhng nu qunhiu nc trong mi trng , r cy trn cn c th b tn hi thm ch gycht v n ngn cn s trao i di chuyn ca oxy v cc kh khc , gia tv kh quyn .

Khi b ngp thi gian ngn , r cy b thiu O2 do O2 ho tan vnchuyn chm trong cc khe t y nc . Khi t m ln s h hp vi sinhvt c kch thch th O2 c th b cn kit hon ton trong vng 24 gi vv vy r chuyn t iu kin thng kh sang mi trng k kh .

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III / nh hng ca nhit :Nhit l yu t quan trng nh hng n s tng trng v pht

trin ca thc vt trong quang hp , h hp , cc phn ng bin dng trns dinh dng nc , khong , s thot hi nc v chuyn nha .

Mt s nghin cu cho thy khi tng nhit mt gii hn hp

lm tng s ht cc cht dinh dng . V d nh r cy i mch non sau10 gi tch lu K+ , NO3- , v Cl- nhiu hn t 5 10 ln so vi 6oC .

V c ch nh hng ca nhit ln s ht khong th nhiunghin cu cho thy nhit nh hng ch yu ln qu trnh traoi cht , ln qu trnh lin kt gia cc phn t trong cht nguyn sinh vicc nguyn t khong .

IV / nh hng ca nh sng :nh sng nh hng mnh n s ht khong . Nu cy bp

trong ti 4 ngy th kh nng hp thu P khng xy ra v kh nng ny s

phc hi dn khi a cy bp ra ngoi nh sng . nh sng cn nh hngn kh nng hp thu NH4 , SO4 tng mnh , trong khi s hp thu Ca ,Mg t thay i . Nhn chung tc ng ca nh sng lin quan n qu trnhquang hp , trao i nc v tnh thm thu ca cht nguyn sinh .

V / nh hng ca nng v t l cc nguyn t khong mitrng n s ht khong :

T l gia cc ion trong mi trng v mi lin quan gia chng vicng ht khong , ngi ta thy c 3 hnh thc tng quan gia ccion : i khng , h tr v khng nh hng ln nhau .

Hin tng i khng ion l hnh thc tng quan ph bin i vicc cation . Th nghim khi tng nng K+ th s hp thu Ca2+ gim ngk .

VI / nh hng ca cc gi th nui trng thu canh :Gi th trng cy phi c nhiu tnh cht ging t , phi l ch

da cho h thng r , to iu kin cho r mc di ra tm nc v chtdinh dng v phi l phng tin cung cp O2 , nc v dinh dng chos sinh trng v pht trin ca cy .

Vic la chn mt ga th no ph thuc vo nh hng ca cc

yu t bao gm gi tin , hiu qu , cn nng , t l xp , kh nng chngli s phn hu , tnh tr , kh nng gi nc , tnh ng u v bn vng ,c v trng cao , bn v c kh nng ti s dng c . Gi th phikhng cha cc vt liu gy c c th nh hng c hi ti mi trngdinh dng v c pH ca mi trng .

PHN IV

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CC LOI HNH THU CANHI / H thng thy canh khng hi lu :

H thng ny cn c gi l h thng m dch dinh dng khng

tun hon m ch s dng mt ln. Khi nng , pH hay dn in thayi, th dch s thay i.- K thut ngm r: cy c trng trong chu cha cc gi th tr

c c l r pht trin c ra bn ngoi chu. chu gi th cha cyngp trong dung dch khong 2-3 cm, mt s r ca cy c ngm trongdung dch cn mt s khc li nm trong gi th tip xc vi khng khnhiu hn.

- k thut ni: Cy c nui trong chu c nh trn vt liu nh nitrn mt dung dch dinh dng v dung dch c thng kh nhn to.

- K thut mao dn: c hai loi chu c s dng trong k thut

ny. cy c trng trong cc chu cha gi th, dung dch dinh dngcha t mt chu cha bn di c mao dn ln ti chu cha cy trn thng qua dy dn.

II / H thng thy canh hi lu :Cn c gi l h thng ng, tc l dch dinh dng c bom

qua h thng r cy v dch d c thu nhn, lm y v ti s dng.- K thut mng mng dinh dng: dung dch dinh dng chy qua

cc knh c dc to ra mt lp mng dinh dng trong knh v tip xctrc tip vi r cy cung cp dinh dng.

- K thut dng su: dung dch dinh dng chy qua cc ng nhaPVC v tip xc vi r cy bng cch thm qua cc chu cha gi th cc l. H thng sp xp cc ng nha theo hnh zig zag tn dng ckhng gian nui cy, th hin c th mnh ca thy canh

III / H thng thy canh c s dng gi th rn :Cc h thng kt hp gia dung dch lng v cc gi th rn cy

pht trin bn trn, h thng c th l ng hoc m:- K thut ti treo: cy ging c cho vo cc l bn ca cc ti

treo chc cc gi th tr ( thng l x da ), di khong 1m, c dng hnhtr, ngoi trng trong en, x l UV dy, lm bng polyethylene. Dchdinh dng c bm ln nh ca mi ti t dch dinh dng s thmxung gi th v ti r cy.

- K thut ti tng trng: cy ging c trng vo cc ti nhatng hp cha gi th ( thng l bt x da kh trng ), chng tia UV,ngoi trng trong en, di khong 1-1.5m, cao khong 6cm v rng khong18cm di mi bn ti c khe nt nh thot nc hoc ra tri.

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- K thut rnh: trng cy vo cc rng cha gi th( c th l btx da c, ct, si, ru, vermiculite, perlite, mc ca c hay hn hp ccvt liu ny) c phn cch vi t bng vt liu khng thm nc. Dchdinh dng v nc c cung cp qua mt h thng ti nh git hayti th cng. y rnh mt ng ng knh 2.5cm c xoi l thot

dch dinh dng tha.- K thut chu mi trng: cy c trng vo cc chu ( bng

t st hay plastic) cha gi th v c cung cp dinh dng bi mt hthng vi ti.

IV / H thng kh canh:Cy trng thc vt c c nh trong cc l trn cc tm xp v r

c treo trong khng kh di cc tm ny. Cc tm ny c xp thnhdng hp knh ngn chn s xm nhp ca nh sng v kch thch stng trng ca r, ng thi ngn chn s tng trng cu to v nm.

Dch dinh dng c phun vo r dng sng, mi ln phun ko dikhong vi giy, 2-3 pht th phun mt ln. Lm nh vy c tc dng gim cho r v dch dinh dng c thong kh. Cy hp thu cht dinhdng v nc t lp dung dch dnh vo r.

Thun li ln ca k thut ny l tn dng khng gian ti a. K thutny c mt cy trng cao gp i so vi k thut khc. Mt ng dng uth khc ca k thut ny l to ra cy sch t t cc mu ct xutkhu.

V / K thut thu canh mng mng dinh dng NFT :

N l mt bin th ca h dng chy su . N cng l dng thu canhhp dn nht i vi cng ng do tnh cht v dng v bn ngoi ca n .Cht dinh dng c cho n vo cc ng d tha rt xung do

trng lc tr li b cha . Mt lp mng mng dinh dng cho php cc rc tip xc n nh vi cht dinh dng v lp kh pha trn cng lc .

PHN VQUI TRNH K THUT THY CANH

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I. H thng thy canh ca trung tm pht trin rau Chu (AVRDC)(Asian vegetables Researche and Deverloppement Center):

H thng thy canh ny do tin s Hideo Imai v tin s DavidMidmore nghin cu v hon thin. H thng gm:a. Mt hp xp c kch thc thay i ty theo tng loi cy trng.

thng c chiu di 50 60cm, rng 40 cm, cao 30 cm. hp xp ctc dnggi cho dung dch nui cy khng b thay i v nhit gysc cho cy (iu kin min Bc, iu kin min Nam).

b. Vt liu chn cy cn gi l gi th cy (dng tro, tru, ct, thanvn, cui).

c. R nha hay ly nha nggi th (nhng loi chuyn dng trngnhng loi cy khc nhau).

V d:Loi trng x lch c th dng 1 r nha, ly nha c ng knh ykhong 3cm, ng knh ming ly khong 4-5cm.Loi trng c tm, c chua, t th phi c kch c ln hn. R nhac cm vo cc np hp xp c l sn.

Trng thy canh cy x lch.

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u im ca h thng :- Dung dch dinh dng ph hp vi mi loi cy trng, c bit

l rau.

- C khong cch thch hp gia cy v dung dch. To iukin cho mt phn r nm l lng v th trong khng kh.Phn cn li nm trong dung dch, ht nc v cht dinhdng.

- i vi nhng cy c thi gian sinh trng ngn (3 -4 tun) thga trnh trng khng cn b sung dung dch nh x lch, cixanh lc c thu hoch th dung dch cng sp ht.

- Hp xp kn c tc dng cch nhit, trnh nh sng cho b r.Hp gn nh di chuyn d dng khi cn thit.

- Xung quanh ni t hp c li nylon che cch ly cn trng

gy bnh.

II. Qui trnh thy canh :1 . Chun b vt liu:

- Hp xp c nylon en ng dung dch. Nylon en c tcdng ngn nh sng bn ngoi khng lt vo dung dch bo vb r.

- Khung g c chn cao khong 15cm chng hp xp vgip cho vic di chuyn c d dng khi cn thit (trnghp c bo).

- Khung bng ng nha hoc tre li che, cy n qu.- Nylon che ma.- R, ly nha.- Li nylon che chn cn trng.- Cc cht dinh dng v nc pha.

2 . Thao tc c th tng bc :a. Chun b khung:

t khung vo ni nh trng cy. Ni c nh sng mt tricng nhiu cng tt, trnh ni khut nng. cn li hng ra

pha ngoi tin m kha chm sc cy.b. Treo li:Treo trn khung , nh trng hp treo mn.

c. Chun b hp xp:Lt nylon en vo trong y hp trc khi d dung dch vohp.

d. Pha dung dch:

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Ln lt ha tan cc dung dch a lng, vi lng, cht stvo hp cha 30 lit nc ong sn.

e. Chun b gieo ht:Ct mnh li lt vo r (ly) cho tro, tru, mt ca, vn x davo dung dch dung dch mao dn lm m gi th, cho ht

ny mm ln ri ph lp tru hun t cung cp mcho ht ging.

f . Theo di v chm sc :- Nu mc nc trong hp tt xung di 15cm so vi mp hp

th cn b sung 5 lit dung dch.- Gia c cc, li, li che, m che ma phng ma to gi

mnh.

III . Mt s im cn lu khi trng thy canh vo ma ma min

Nam :Trc khi trng, cn che ma cho cy. Tt nht nn lm mi che ttm lp nha cng trong sut c mu hng, mu xanh da tri hoc khngmu. Khong cch gia mi che v nn khong 3cm. C li bao quanhcng tt trnh ht ma v cn trng.

Cn t cc hp xp trng cy trn cc b gch chng nng nhiu lthng dng chng nng cho trn nh, hoc b bng g r tin nh cppha dng risao cho khong cch t hp xp ti sn khong 30 40cm.

Khng bao gi cho dung dch ngp ton b r hoc r nha en v

nh th lm cho cy khng h hp c. lun gi cho khong cch na br ra khi r nha th r ch c ngp vo dung dch khong 2cm, phncn li phi nm trong phn khng kh bn trong hp.

Ni t hp phi c chiu nng ti thiu 6 gi/ngy i vi cyrau.

Cn ch li trng bao quanh, phi chn loi khng gi nhit khng lm tng nhit bn trong cy trng nht l vo ma h minNam.

IV . So snh gia cy trng cn t v thy canh :

Trng cy cn t Thy canhTrong t trng, cc vi khun phiphn ct cc cht hu c phc tpthnh cc nguyn t c bn nhnitrogen, phosphor, potassium(kali) cng nh cc nguyn t vt(vi lng).

Thc n cho cy c cn bng(dung dch dinh dng) c hatan thng vo nc nn thc vtc th nhn cht dinh dng honho mi lc.

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t trng khng th sn sinh nhiucht dinh dng trn mi din tch cho h r hp thu.

Thy canh mang lng thc nc cn thng ti r hn l bt rthc vt tm ti n.

t trng gim st gi tr dinhdng ca n v kh o cc pH

v mu m.

Gi tr pH v dinh dng ca ncc o v duy tr d dng, v vy

thc vt lun c n.Ch khi cc cy trng trn t cti, cc nguyn t c bn mi cth ha tan vo nc.

Trong mt h thng thy canh, m hin din trong cc khong thigian c ko di hay trong milc.

t trng ng vai tr vt ch ivi nhiu vi sinh vt c hi.

Cc mi trng trng thy canh ltr, v trng, mt mi trng rt vsinh cho thc vt v ngi trng.

t trng cn nhiu vic ti, cs hin hin ca cc sinh vt gy

hi cao hn, thc vy ln chmhn, cn nhiu khng gian v schm sc hn.

Thy canh lm tng s sinh trngv sn lng trn mi din tch ca

thc vt , gim cc sinh vt gyhi, bnh tt v nhu cu ti ncca thc vt.

V . Mt v d v qui trnh k thut thy canh:

X lch v rau mung thy canh, Cn Th

U IM :

1. Khng phi lm t khng c c di.

2. Trng c nhiu v, c th tri v, khng cn ti.

3. Khng phi s dng thuc tr su bnh, tr c di.

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4. Nng sut cao hn t 25% n 50%.

5. Sn phm hon ton sch ng nht.

6. Ngi ga yu tr em c th tham gia c hiu qu.

7. Khng tch ly cht c, khng gy nhim mi trng.

IU KIN TRNG :

Tn dng mt bng sn thng, ban cng hay khong sn trc nh:

- nh sng cho cy quang hp t nht 5-6 gi trong mt ngy.

- Cn trnh nc ma dung dch dinh dng khng b pha long, c thlm mi che bng ni lng trng.

- Cn phun nc 2-3 ln vo bui tra nng gt i vi rau n l.- Cn trnh cho cy khi b nght th: Khng bao gi cho dung dch ngphon ton b r, cha phn na b r nm trn mt dung dch.

VT LIU

1. Hp xp (45 x 60 x 15 cm)

2. Cht dinh dng

3. R nha gieo ht4. Ht rau (x lch, rau mung, ci xanh, ci ngt, hng qu...)

5. X da, tro tru

6. Bnh phun nc

TRNH T THAO TC :

1. Chun b hp xp: Hp xp c sn en bn trong hoc lt ni long en ng dung dch.

2. Khoan l: Dng ng nc bng nha (c ng knh tng ngming r) c l trn np hp, s l ph thuc vo tng loi cy trng: Raumung, x lch, ci xanh, ... c th 24 l.

3. Chun b r gieo ht: Dng x da nhi di y r, nhi tro tru bntrn, t r vo cc l c trn np hp.

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Chun b hp xp, sn en; Khoang l trn np ht; Chun b r gieo ht

4. Gieo ht: 2-3 ht vo mi r su khong 1cm

5. Pha dung dch: Dinh dng c c ng trong chai, lc tht u vothng xp, thm lng nc theo hng dn, sau khuy u. Mcnc cch ming thng t nht 2 cm.

6. Kt thc: t np hp c sn r nha gieo ht ln trn hp xp chadng dch dinh dng, sao cho y r nha ngp trong dung dch t 1-2

cm.

Gieo 2 - 3 ht vo mi r; Pha dung dch dinh dng; t np hp lnthng

Ch : Theo di mc nc trong hp xp, cn pha dinh dng thm vokhi mc nc thp hn b r.

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NHN XT CHUNG

Qua , chng ta c th hiu thm phn no v mt cng ngh tin

tin sn xut ra cc sn phm sch phc v i sng con ngi. Tuy rngh thng nui trng thy canh vn cha hon ton l mt gii php honho cho vic phc v i sng ca con ngi nhng phi ni rng cho nthi im hin ti th y l mt cng c gip ch rt c hiu qu cho nhucu ca chng ta .

Trong tng lai s cn rt nhiu cuc nghin cu nng cao chtlng h thng ny v mong rng con ngi s ngy cng gim bt cgnh nng lo lng v an ton sc kho cho bn thn mnh v cho gia nh.

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TI LIU THAM KHO

my.opera.com

www.cuctrongtrot.gov.vn

www.hcmbiotech.com.vn

rausach.com.vn

Sch : thu canh cy trng (TS V Th Bch Mai )( Nh xut bn i hc Quc Gia TPHCM 2003 )
http://www.cuctrongtrot.gov.vn/http://www.hcmbiotech.com.vn/http://www.cuctrongtrot.gov.vn/http://www.hcmbiotech.com.vn/

thuy canh w

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