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7/24/2019 Nghin cu bn phn cn i cho Ng trn t bc mu

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b gio dc v o to

trng I hc nng nghip I

NGUYN TH TI

Nghin cu bn phn cn i cho ngtrn t bc mu

lun vn thc s nng nghip

Chuyn ngnh: khoa hc t

M s: 60.62.15

Ngi hng dn khoa hc: PGS.Ts. NGUYN NH H

H Ni - 2007


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Trngi hc Nng nghip H Ni - Lun vn Thc skhoa hc nng nghip ---------------------- i

Li cam oan

Ti xin cam oan y l cng trnh nghin cu ca ring ti. Cc s

liu, kt qu nu trong lun vn l trung thc v cha tng c ai cng b

trong bt k cng trnh no khc.

Ti xin cam oan rng cc thng tin trch dn trong lun vn u

c ch r ngun gc.

Tc gi lun vn

Nguyn Th Ti


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Trngi hc Nng nghip H Ni - Lun vn Thc skhoa hc nng nghip ---------------------- ii

Li cm n

Trong sut qu trnh hc tp v thc hin ti, ti nhn c s

gip , nhng kin ng gp, ch bo qu bu ca cc thy c gio Khoa

Sau i hc, Khoa t v Mi trng, Trng i hc Nng nghip I H

Ni.

c c kt qu nghin cu ny, ngoi s c gng v n lc ca

bn thn, ti cn nhn c s hng dn chu o, tn tnh ca PGS.TS

Nguyn Nh H, l ngi hng dn trc tip ti trong sut thi gian thi

gian nghin cu ti v vit lun vn.

Ti cng nhn c s gip , to iu kin ca Trung tm khuyn

nng huyn Bnh Xuyn - tnh Vnh Phc, UBND x Qut Lu - huyn Bnh

Xuyn, b con nng dn x Qut lu, bn b ng nghip, s ng vin, to

mi iu kin v vt cht, tinh thn ca gia nh v ngi thn.

Vi tm lng chn thnh, ti xin cm n mi s gip qu bu !

Tc gi lun vn

Nguyn Th Ti


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Trngi hc Nng nghip H Ni - Lun vn Thc skhoa hc nng nghip ---------------------- iii

Mc lc

Li cam oan iLi cm n ii

Mc lc iii

Danh mc cc ch vit tt v

Danh mc bng vii

1. M u i

1.1. t vn 1

1.2. Mc ch ca ti 21.3. i tng v phm vi nghin cu ca ti 2

2. Tng quan ti liu 3

2.1. c im chung v cy ng 3

2.2. c im sinh l dinh dng ca cy ng 4

2.3. Kt qu nghin cu bn phn cho cy ng 15

2.4. S cn thit phi bn phn cn i cho ng 29

3. Ni dung v phng php nghin cu 34

3.1. Ni dung nghin cu ca ti 34

3.2. Phng php nghin cu 34

4. Kt qu nghin cu v tho lun 37

4.1. Kt qu phn tch t trc th nghim 37

4.2. nh hng ca bn thm cc cht dinh dng th cp n mt s ch

tiu sinh trng ca cy ng 37

4.2.1. nh hng ca cc cht dinh dng th cp n s pht trin chiu

cao cy ng 37

4.2.2. nh hng ca cc cht dinh dng th cp n s ra l ca cy ng39


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Trngi hc Nng nghip H Ni - Lun vn Thc skhoa hc nng nghip ---------------------- v

4.8.2. nh hng ca bn thm cc cht dinh dng th cp n vic tch

lu N, P, K trong ph phm ca cy ng 57

4.9. nh hng ca bn thm cc cht dinh dng th cp n vic ht N,

P, K ca cy ng 58

4.10. nh hng ca bn thm cc cht dinh dng th cp ti cn bng

dinh dng trong bn phn cho ng 60

5. Kt lun v ngh 62

Ti liu tham kho 63


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Trngi hc Nng nghip H Ni - Lun vn Thc skhoa hc nng nghip ---------------------- vi

Danh mc ch vit tt

K hiu Ni dung

CT Cng thc

CTTN Cng thc th nghim

STSD Sinh trng sinh dng

STST Sinh trng sinh thc

TGST Thi gian sinh trng

LAI Ch s din tch l

PTNT Pht trin nng thn


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Trngi hc Nng nghip H Ni - Lun vn Thc skhoa hc nng nghip ---------------------- vii

Danh mc cc bng

Bng 4.1. Mt s ch tiu nng ho ca t nghin cu 37

Bng 4.2. nh hng ca vic bn thm cc cht dinh dng th cp

n chiu cao cy ng qua cc thi k sinh trng 38


n s l cy ng qua cc thi k sinh trng 40


n cc yu t cu thnh nng sut v nng sut ng 41

Bng 4.5. nh hng ca bn thm cc cht dinh dng th cp ntnh hnh su, bnh hi ng 45

Bng 4.6.nh hng ca bn thm cc cht dinh dng th cp n

nng sut sinh khi v h s kinh t ca cy ng 48

Bng4.7. nh hng ca bn thm cc cht dinh dng th cpti

mt s ch tiu cht lng ht ng 50

Bng 4.8. nh hng ca cc ch bn phn n hiu qu s dng

phn bn cho ng 52


n hiu sut s dng phn bn cho ng 53

Bng 4.10. nh hng ca bn thm cc cht dinh dng th cp n

vic tch lu N, P, K trong sn phm thu hoch ca cy ng 55


vic ht cc cht dinh dng a lng vo cy ng 58


cn bng dinh dng cho ng 60


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Trngi hc Nng nghip H Ni - Lun vn Thc skhoa hc nng nghip ---------------------- 1

1. M u

1.1. t vn

Cy ng c tn khoa hc Zea mayL, l mt trong nhng cy lng

thc quan trng hng u trn th gii ch sau la m v la nc, cung cp

ngun dinh dng quan trng cho ngi v ng vt, ng thi l nguyn

liu cho nhiu ngnh cng nghip.

Vit Nam, ng chim v tr quan trng trong c cu cy trng v sn

xut nng nghip. Gp phn ng k vo vic tng tng sn lng lng thc

v thu nhp cho nng dn.

Ng l cy trng pht trin mnh trn vng t bc mu do kh nng

chu hn v tnh thch ng rng nhng cng l cy c yu cu thm canh hp

l mi t hiu qu sn sut cao.

Trong thm canh cy ng, ngoi nhng yu t nh ging, k thut canh

tc th bn phn l mt bin php k thut khng ch c tc dng ln ti nng

sut, phm cht m cn l khu u t c nh hng quyt nh ti hiu qu

trng trt, c bit khi trng ng trn t bc mu.

mi thi k sinh trng, cy ng cng mt lc ht nhiu cht dinh

dng t a lng (N, P, K), trung lng (Ca, Mg, S) n vi lng (Zn, Cu,

Mn) theo mt t l cn i v xc nh (nhu cu cn i dinh dng). V vy

cy ng pht trin kho mnh cho nng sut cao, phm cht tt ngoi m

ln, kali, tu theo kh nng cung cp dinh dng ca t, cn quan tm cung

cp cc cht dinh dng thit yu theo yu cu ca cy - hay cn gi l bn

phn cn i. Nh m nng cao hiu qu phn bn, gim chi ph sn xut,

tng thu nhp cho ngi sn xut, ng thi n nh ph nhiu ca t v

gim thiu kh nng nh hng xu ca phn bn ti mi trng, to c s rt

quan trng cho vic pht trin sn xut ng bn vng.


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t bc mu l loi t ngho cc cht dinh dng nhng c din tch

ln v trng c nhiu loi cy khc nhau, trong c cy ng. V vy

m bo sn xut ng cho hiu qu cao trn t bc mu rt cn bn thm

cc cht dinh dng khc ngoi N, P, K m bo bn phn cn i. Tuynhin trong thc t sn xut ngi trng ng thng ch quan tm bn cc

loi phn N, P, K m cha quan tm ti nhu cu v cc cht dinh dng thit

yu khc. V vy cn thng qua nghin cu trong iu kin sinh thi c th

(t ai, ma v) xc nh nhu cu v hiu lc ca cc cht dinh dng

th cp nu trn. Xut pht t thc t trn chng ti tin hnh ti:

"Nghin cu bn phn cn i cho ng trn t bc mu".

1.2. Mc ch ca ti

Xc nh hiu lc ca cc cht dinh dng th cp (Ca, Mg, S, Zn, B)

i vi cy ng (ngoi N, P, K) nhm to ra cng thc bn phn cn i v

hp l cho cy ng trn t bc mu.

1.3. i tng v phm vi nghin cu ca ti

- Nghin cu c thc hin trn t bc mu vi ging ng lai thm

canh (LVN - 4) ti x Qut Lu, huyn Bnh Xuyn tnh Vnh Phc v ngnm 2006.

- Trong th nghim c s, dng cc loi phn m, ln, kali v cc

phn cha cc cht Ca, Mg, S, B, Zn v phn a yu t chuyn dng cho cy

ng trn t bc mu.


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2. Tng quan ti liu

2.1. c im chung v cy ng

Cy ng l cy lng thc c tim nng nng sut cao, nng sut k lc

trn th gii t 22 tn ht/ha. Ng ngoi tc dng l lng thc cn l

ngun thc n v nguyn liu sn xut thc n chn nui rt quan trng [11].

Cy ng c a vo trng Vit Nam t th k XVII. T cy ng

nhanh chng thch nghi vi iu kin t ai, kh hu ca nc ta, nn din

tch trng ng ngy cng c m rng.

Hin ti din tch trng ng Vit Nam chim v tr th hai sau lanc. Cy ng c v tr rt quan trng trong c cu cy lng thc cc tnh

trung du v min ni, do y nhiu dn tc s dng ng nh mt loi

lng thc chnh. ng bng, ng c trng nhiu trn cc vng t bi

ven sng v chim t l ln trong c cu cy trng v ng trn t hai v

la ca ng bng Bc B [11].

Trong nhng nm gn y ngh trng ng ca nc ta c bc pht

trin ln, m tin l cng tc lai to, chn lc, nhp ni cc ging mi c

nng sut cao, thch nghi rng thay th tng bc cc ging c ca a

phng. ng thi cc nghin cu v k thut trng, bn phn... c trin

khai, tng bc hon thin quy trnh k thut sn xut ng cho tng nhm

ging, tng vng sinh thi khc nhau to iu kin cho ngi trng ng yn tm

sn xut v vy nng sut v sn lng cng ngy mt tng cao [11].

Ng l cy c th trng trong nhng iu kin kh hu khc nhau: tuy

nhin nhit ti thch cho ng sinh trng mnh t 21 - 270C, nhit di

190C ng sinh trng chm li. Cy ng c kh nng chu hn v s dng nc

tit kim, nn ni c lng ma thch hp cho trng ng trong khong 600 -

900 mm/nm. Nhng cy ng cn nhiu nc v pht trin thun li, cho nng


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sut cao trong iu kin m cao, nht l giai on 7 - 9 l ti tr c [ 11].

Cy ng khng kn t nhng thch hp nht trn t ti xp, c pH t

t chua - trung bnh (5,6 - 7,0) giu mn v dinh dng. Ng l cy phm n,

do vy mun trng ng t nng sut cao th phi trng ng trn t c

mu m cao. Ng c th mc tt trn bt k mt loi t no nu c h thng

ti tiu y duy tr oxy cho r pht trin, hot ng tt v c kh

nng lu gi nc to m sut ma sinh trng. Nu trng ng trn t

bc mu th phi bn phn y v cn i [16].

Cy ng c th trng c nhiu v trong nm, min Bc thng

trng ng v ng, ng xun. Min Nam thng trng ng trong cc v h

thu v ng xun.

2.2. c im sinh l dinh dng ca cy ng

2.2.1. c im sinh trng v pht trin ca cy ng

Giai on sinh trng sinh dng (STSD) ca cy ng c bt u t

ny mm n khi tr c (khong 55 - 60 ngy), trong gm cc thi k

sau: ny mm - t gieo ht n khi cy c 3 - 4 l tht, cy pht trin ch yu

da vo dinh dng trong ht. Cy con - t khi cy 3 - 4 l n khi ng 7 - 9

l, cy cn c cung cp dinh dng cha nhiu do cn pht trin chm.

Vn cao v phn ho c quan sinh sn, t khi cy ng c 7 - 9 l n tr c,

cy pht trin mnh nn cn c cung cp nhiu dinh dng [11].

Giai on sinh trng sinh thc (STST) c bt u t khi ng tr c

phun ru ti chn, trong gm cc thi k: n hoa din ra trong vng 10 - 15

ngy, l thi k pht trin mnh v c nh hng quyt nh n nng sut ng

ht, cn cung cp nhiu dinh dng. Chn, ko di trong 35 - 40 ngy vi thi k

hnh thnh ht - xy ra tch lu cht kh mnh v thi k chn - kh ht v thn

l. Nh vy giai on STST ca cy ng c 35 - 40 ngy u l giai on cy

ng sinh trng pht trin mnh, yu cu c cung cp nhiu dinh dng [11].


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2.2.2. c im h r ca cy ng

Ng c h r chm, cn c vo hnh thi, v tr v thi gian pht sinh, c

th chia b r ng ra thnh 3 loi: r mm, tn ti t ny mm n khi ng 4 - 5

l, r t - pht trin t t thp nht, nm di mt t t 3 - 4 cm xut hinkhi ng c 4 - 5 l, chim u th tuyt i lm nhim v ht nc v thc n

trong sut i cy ng. R chn king mc t t gn st trn mt t lm

nhim v chng cho cy, cng tham gia ht nc v cht dinh dng [11].

B r ng c th n su 80 - 90 cm v lan rng 120 - 140 cm, phm vi

hot ng ca r ng c khc nhau tu thuc thi k sinh trng tnh theo s

l: 3 - 4 l; r lan rng 10 - 12 cm, n su 18 - 20 cm; 5 - 6 l: r lan rng 30

- 35 cm, n su 50 - 60 cm; tr c: r lan rng 60 - 70 cm, n su 80 - 90 cm;hnh thnh ht: r lan rng 90 - 100 cm, n su khong 200 cm. Trong iu kin

thch hp r ng c th m rng v m su khong 60 cm sau 4 tun trng.

thi k ra hoa gia cc hng ng gn nh c bao ph bi mt lp r. Lm t

r khi xi xo l hin tng kh trnh, v th sau khi xi xo cn tng cng

bn phn v ti nc gi m cho t r ng chng hi phc [11].

Nhn chung cy ng c b r pht trin, to kh nng chu hn v khai

thc c nhiu dinh dng t t cho cy.2.2.3. Yu cu dinh dng ca cy ng

Cy ng ht nhiu kali v m ri n ln ... Lng dinh dng cy ht

tu thuc vo nng sut, nng sut cng cao, dinh dng ly i cng nhiu.

Bng 2.1. Lng dinh dng cy ng ht to ra 10 tn ht/ha (kg/ha)

B phn N P2O5 K2O MgO CaO S CL Fe Mn Zn Cu B

Ht ngThn, l, r

19079

7833

54215

1838 45

1618

9,89,0

Tng s 269 111 269 56 45 34 18,8 3,4 0,6 0,6 0,2 0,1

Ngun: dn theo Nguyn Nh H [11]


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Smaraep T.E., tng kt vic bn phn cho ng M cho thy mun

thu hoch 36 t/ha cn bn khong 134 kg N, 33,6 kg P2O5v 112 kg K2O

cho ha [34]. Theo Trn Hu Min (1987) 1 tn ng ng xun cn 25 - 28 kg

N, 1 tn ng xun cn 28 - 30 kg N, 1 tn ng h thu cn 32 - 35 kg N, 1 tnng thu ng cn 30 - 33 kg N [13]. Theo T Vn Sn (1995) trong iu kin

thm canh t nng sut 45 - 50 t/ha, lng cht dinh dng cy ng ht

to ra 1 tn ng ht l 33,4 - 38,9 kg N, 12,3 - 14,0 kg P2O5, 23,8 - 28,9 kg

K2O [24]. Theo Nguyn Vn B (2001) ng l cy trng c tim nng nng

sut cao ng thi cng c nhu cu dinh dng ln. Trung bnh vi nng sut

6 tn/ha cy ng ht 155 kg N, 60 kg P2O v 115 kg K2O [3].

2.2.3.1. Nhu cu m ca cy ng

Cy ng cng nh cc loi cy trng khc rt cn m sinh trng

pht trin. m xc tin mnh pht trin r, thn, l, cht kh, to kh nng

quang hp ti a v tch lu nhiu vo ht. m lm cho bp ng to, nhiu

ht, to ra nng sut sinh hc v ht cao. m cn lm tng t l protit trong

ht, tng gi tr dinh dng ca ht ng. m ng vai tr quyt nh n

nng sut v phm cht ht [17].

Khi cy ng thiu m th cc l pha di s bt u vng i chp l

v lan dn dc theo gn l chnh. Cc du hiu thiu m s chuyn dn ln l

trn v cc l di s cht trc. Thiu m cn lm cy sinh trng pht trin

chm, ci cc, bp nh, ht lp dn n nng sut sinh vt v ht u thp.

c bit nu thiu m nhiu v ko di c th lm cht cy con hay khng

cho thu hoch [36].

Khi cy ng tha m c hin tng pht trin mnh thn l, ko di

thi gian sinh trng, c th b lp .

Nhu cu m to ra 1 tn ng ht khong 27 kg N v tu thuc ma

v m c th khc nhau [11]. Theo T Vn Sn (1995) cc ging ng mi c


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nhu cu dinh dng m cao trong sut qu trnh sinh trng pht trin. t

nng sut 40 - 50 t/ha lng m cy ht to ra mt tn ng ht l 33,4 -

38,9 kg N. Kt qu nghin cu ca vin Ln - Kali Atlanta (M) cho thy to

ra 10 tn ng ht cy ng ly i lng m l 269 kg N/ha [31]. Nguyn XunTrng (2000) cho bit to ra 9,5 tn ht/ha cy ng ly i mt lng m

l 191 kg N [29]. Trong sn xut chng ta ang trng nhiu loi ging ng c

c im sinh trng v mc s dng m khc nhau. Nhn chung cc ging

ng mi, cc ging ng lai cho nng sut cao cn lng m nhiu [13].

Trong qu trnh sinh trng giai on cy con, lng dinh dng

cy ht t nhng cng rt quan trng v thiu m vn nh hng rt xu ti

pht trin sau ny ca cy. Vic ht m ca cy ng bt u tng ln rtnhanh t sau khi ng c 7 l v t ti a trong khong giai on t 10 ngy

trc v 25 ngy sau khi tr c, thiu m thi k ny nng sut ng gim

rt r rt. Sau giai on ny vic ht m ca cy ng li gim mnh. Nh

vy trong vng i cy ng c hai thi k u v cui ca qu trnh sinh

trng nhu cu v m thp, cn cc thi k gia nhu cu m rt cao cn

quan tm cung cp dinh dng N cho cy vo cc thi k ny [11].

Cy ng phn ng rt r vi phn m. Bn phn m, lm ng sinh trng

pht trin mnh, l xanh cy mp. Trn chn t ngho dinh dng, phn m l yu

t quyt nh nng sut sinh hc v nng sut ht ca cy ng [28]. Do m c trong

thnh phn cu to tt c cc cht protit v axit nucleotit, l nhng cht gi vai tr

quan trng trong qu trnh trao i cht ca cy nn thc y qu trnh sinh trng

ph t trin, to nng sut ca cy ng v nng cao hm lng protit trong sn phm.

Tt c cc loi t trng trt u cn phi bn thm m, c bit trn cc loi t c

ti [2]. Theo Berger K.C., hin tng thiu m cy t khi c pht hin sm.

Khi cy ng c 3 - 5 l th tc sinh trng gia t ng do nhu cu m ca cy

cng tng nhanh. Thng thng cy ng cn khong 3,5 kg N/ha/ngy v c th

t ng gp i nhu cu ny giai on cy cn nhiu m.


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Theo Nguyn Mng (1968) t lc mc n lc tr cy ng ht 2/3

lng m, s cn li ht t tr v sau [16].

Bng 2.2. T l dinh dng cy ng ht trong qu trnh sinh trng

(nghin cu trn cy ng c TGST 125 ngy)

Cht dinh

dng

25 ngy

sau ny

mm

25-50 ngy

sau ny

mm

50-75 ngy

sau ny

mm

75-100

ngy sau

ny mm

100-125

ngy sau

ny mm

Tng

s

N % 8 35 31 20 6 100

P2O5 % 4 27 36 25 8 100

K2O % 9 44 31 14 2 100


Theo Vin Ln - Kali Atlanta (M) [31] lng m c cy ng ht

trong cc thi k sinh trng tng ng nh sau: cy con 21 kg N, sinh

trng sinh dng 94 kg N, phun ru 84 kg N, to ht 54 kg N v chn 16 kg

N. Nghin cu M vi cc ging ng c thi gian sinh trng 125 ngy

cho thy: 25 ngy u nhu cu v m ch chim 8% tng nhu cu. 25 ngy

tip theo nhu cu m tng ln rt nhanh chim 35% so vi ton b nhu cu

(ng vi thi k hon chnh b r v to thn l, phn ho cc c quan sinh

sn). 25 ngy tip theo cy ng vn yu cu lng m cao chim 31% so

vi ton b nhu cu (l thi k hon thin cc b phn sinh sn v th phn).

25 ngy tip theo cy ng cn 20% tng lng m nui ht. 25 ngy cuinhu cu m ca cy ng ch chim 6% so vi ton b nhu cu. Nh vy

trong vng i ca cy ng hai thi k sinh trng u v cui c nhu cu

m thp, cn cc thi k gia nhu cu m rt cao.


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2.2.3.2. Nhu cu ln ca cy ng

Cng nh m, ln c vai tr quan trng i vi i sng cy ng. Ln

tham gia vo thnh phn cc hp cht nucleotit: ADN v ARN, cc hp cht

cao nng lng ATP, ADP y l nhng cht quan trng nht trong qu

trnh phn chia t bo, to mi cc b phn c th.

i vi cy ng ln c tc dng xc tin h r pht trin mnh, nh

hng tt n qu trnh to cc c quan sinh trng, tng kh nng chng

chu vi nhit thp v hn, ng thi to kh nng chng chu su bnh

hi tt hn cho cy ng. Ln cn c nh hng tt n bng c, hoa, bp,

lm tng cht lng ht v sc sng ca ht, thc y nhanh qu trnh chn.Cy ng ht ln kh tan trong t rt km, do vy ng c dng lm cy ch

th nh gi lng ln d tiu trong t. Ln c vai tr hn ch nhng tc

ng xu khi bn tha m [11, 35, 36].

Thiu ln thng xy ra thi k cy con, cn tr vic hnh thnh cc sc

t nn lm cc l gi v thn c mu tm, cy mc yu. Vo u v bt k s

hn ch t nhin no i vi s pht trin ca r u dn n hin tng thiu

ln, ngay c khi ln trong t cung cp cho cy. Vic thiu ln lm cyng c bp nh, mo m nhiu ht lp, chn mun [11].

giai on cy ng c 3 - 4 l, ln c vai tr quan trng d nhu cu

khng nhiu v l thi k khng hong ln ca cy ng, nu thiu ln trong

giai on ny s lm gim nng sut nghim trng. Nhu cu ln ca cy ng

tng mnh trong khong thi gian 25 - 50 ngy sau mc, do cn cho s pht

trin ca b r, cc c quan sinh trng, phn ho hoa, to tin cho nng

sut cao sau ny. Thi k 50 - 100 ngy sau trng (trc tr c n lm ht),cy ng ht lng ln ln nht (khong 65%), c bit vo thi k th phn

to ht. Thi k chn yu cu ln gim dn, 25 ngy trc thu hoch cy ch

ht 5% so vi tng nhu cu ca cy ng. Nh vy cng ging N, nhu cu ln


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ca cy ng c hai thi k u v cui ca qu trnh sinh trng thp, cn

cc thi k gia nhu cu ln rt cao [11].

Qua phn tch, ngi ta thy ln c trong ht ng t l 0,55 - 0,60%

v trong thn l 0,30 - 0,35% [28]. Theo Berger K.C., s thiu ht ln ng

thng xy ra thi k cy con, biu hin u tin l l c mu tm v

cc biu hin khc nh l thn mc thng, yu, bp nh, mo m v ht lp.

Thiu ln cn dn n hin tng chn mun, bng c nh v t hoa. Vo u

v, bt k mt s hn ch t nhin no i vi s pht trin ca r nh: nhit

thp, t qu kh hay qu m u dn n hin tng thiu ln ngay c

khi ln trong t cung cp cho cy [37]. Theo Trn Vn Minh (1995)

ln c tc dng lm tng nng sut ng r rt, nng sut ng t l thun vi

lng ln bn [15].

Theo T Vn Sn (1995) cc ging ng mi c nhu cu dinh dng

ln cao t nng sut 45 - 50 t/ha, lng dinh dng ln c cy ng

cn ly i t t to ra mt tn ng ht l 12,3 - 14,0 kg P2O5[24]. Theo

Vin Ln - Kali Atlanta (M), to ra 10 tn ng ht/ha cy ng ht mt

lng ln l 111 kg P2O5. Theo Nguyn Xun Trng (2000) to ra 9,5 tn

ht/ha cy ng ly i mt lng ln l 89 kg P2O5 [29].

Nguyn Mng (1968) cho bit t lc mc n lc tr cy ng ht

1/2 tng nhu cu ln v s ln cn li cy ng ht t tr v sau [16].

Theo T Vn Sn (1995) cc ging ng mi c nhu cu dinh dng ln

cao v ht ln mnh thi k sau tr c [24]. Theo Vin Ln - Kali

Atlanta (M), to ra 10 tn ng ht/ha lng ln ht trong cc thi k

sinh trng tng ng nh sau: cy con 4 kg P2O5, sinh trng sinhdng 30 kg P2O5, phun ru 40 kg P2O5, to ht 28 kg P2O5v chn 9 kg

P2O5 [31]. inh Th Lc (1997) cho bit mc d lng ln cy ht trong

50 ngy u ch l 30% tng nhu cu nhng ln l yu t sng cn cho s


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pht trin ban u ca cy, do c tc dng phn ho cc b phn kch

thch s pht trin ca b r, phn ho hoa c hoa ci, to tim nng,

nng sut cao sau ny. Thi k 50 ngy tip theo, nht l thi k to ht,

cy ng ht ln ln chim khong 65% tng nhu cu tch lu cc chtto ht, cy ht ln t ti 1,7 kg/ha/ngy. Thi k chn cy yu cu ln

gim dn, cy ch ht 5% so vi tng nhu cu ca cy ng [17].

2.2.3.3. Nhu cu kali ca cy ng

i vi cy ng kali c coi nh l nguyn t quan trng th hai sau

m th hin lng ht kali xp x lng ht m. Kali c vai tr trong duy

tr cc chc nng sinh l, cn thit cho hot ng ca keo nguyn sinh cht,

xc tin qu trnh quang hp, vn chuyn cc sn phm quang hp tch lu v

ht. Kali thc y qu trnh ht cc cht dinh dng khc, sinh trng pht

trin, quang hp, vn chuyn tch lu cht kh vo ht ng. ng thi c nh

hng ln n hiu qu s dng nc, km hm s thot hi nc, tng kh

nng chng chu sng gi, nhit thp v su bnh hi, lm b r pht trin

mnh v n su xung t [11, 17]. Kali l nguyn t a lng khng trc tip

tham gia vo cc cu trc c th cy trng, tuy vy kali gi vai tr quan trngtrong qu trnh trao i ng, bt v trao i protit, xc tc cho qu trnh hot

ng ca cc loi men. Kali c tc dng lm giu hm lng ng, bt,

protein trong cy v trong ht [1].

Theo T Vn Sn (1995) bn kali lm tng t l K, gim t l N trong

thn l, lm cn i dinh dng ca ng, c tc dng lm tng tui th ca l,

tng sinh khi v tng nng sut [24]. S kh hn s gy nh hng r rt khi

khng cung cp kali [37].

Thiu kali lm cho b r ca cy ng km pht trin v pht trin theo

chiu ngang; cy d v km chu hn; ban u dc theo mp cc l di


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c mu vng hoc lu ri lan dn vo gn l v cc l trn; t thn cy ngn,

pha bn trong t c mu nu m; bp ng nh, ht d bong khi li [11].

Theo Berger K.C khi cy thiu kali cc l pha di b vng hoc nu

v lan dn vo gn l, ln cc l trn. Mt triu chng thng thng khc ca

s thiu kali l khi ct dc thn cy s thy cc t bn trong c mu nu

m. Thiu kali t nh hng n kch thc ca bp, nhng cc ht u

mt khng pht trin v c th lm bp lp [37].

Tha kali gy hin tng thiu Ca v cn tr vic hp th Mg, B, Zn v

c m amn ca cy ng [11].

Theo Vin Ln - Kali Atlanta (M), to ra 10 tn ng ht/ha cy ng

ly i mt lng kali l 269 kg K2O [30]. Theo Nguyn Xun Trng (2000)

to ra 9,5 tn ht/ha cy ng ly i mt lng kali l 235 kg K2O[28].

Hu ht nhu cu kali ca cy ng c ht giai on sinh trng

sinh dng, cho ti tr c, cy ng ht khong 84% lng kali cy

cn. Nguyn Mng (1968) cho bit t lc mc n lc tr cy ht 3/4

lng kali, s cn li ht t tr v sau [16, 31]. Nhng 25 ngy u cy

ng cng ch ht 9% tng nhu cu. Cy ng ht kali nhiu nht vo cc

thi k gia nhm to t, pht trin thn l, th phn, kt ht (25 - 50

ngy sau mc cy ng ht 43%; thi k phun ru - kt ht 30%). Cc thi

k sau vic ht kali gim mnh (thi k hnh thnh ht 14%; thi k chn

2%).Kali tch lu nhiu thn l (khong 80%) v tch lu trong ht t

hn nhiu [31].

Theo Berger K.C cc thi k m nhu cu dinh dng cao, cy ng

ht kali nhiu hn m [37]. Theo inh Th Lc (1997) cc thi k to t,

th phn, chn sa v chn cy ng cn nhiu kali, cn phi bn phn b sung

nu t c biu hin thiu kali [17].


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2.2.3.4. Nhu cu v cc yu t dinh dng khc ca cy ng

Ngoi m, ln, kali cc nguyn t th cp cng rt cn thit i vi sinh

trng pht trin, nng sut v phm cht ca cy ng.

Canxi c vai tr tng cng s vng chc cho mng t bo, to lp

lng ht ca r v tch lu tinh bt. Canxi cn ng vai tr trong trao i cht

hidrat cacbon v protit. Canxi l nguyn t i khng vi st, hn ch tnh

c ca st d tha, n nh qu trnh dinh dng cy ng. Bn vi c tc

ng ci to t, ngoi ra, cn cung cp lng canxi cn thit cho cy [28].

Theo Vin Ln - Kali Atlanta (M), to ra 10 tn ng ht/ha cy ng ly i

mt lng canxi l 45 kg CaO [31]. Nguyn Xun Trng (2000) to ra 9,5

tn ht/ha cy ng ly i mt lng canxi l 57,1 kg CaO [29]. Trung bnh

vi nng sut ht 6 tn/ha cy ng ht 15,7 kg CaO [4].

Magi tham gia vo thnh phn dip lc v mt s coenzym, c vai tr

trong qu trnh oxy ho kh ca cy cng nh qu trnh ng ho v vn

chuyn photpho. Magi gn cc khu trong qu trnh chuyn ho hidrat

cacbon, tng hp cc axit nucleic, thc y qu trnh chuyn ho v hp thung ca cy. Thiu magi c th thy trn t chua, t xi mn ra tri

mnh vi biu hin l xut hin nhng l di cc sc trng dc theo gn l

v mp l c mu tm [28]. Theo Vin Ln - Kali Atlanta (M), to ra

10 tn ng ht/ha cy ng ly i mt lng magi l 56 kg MgO [31]. Nguyn

Xun Trng (2000) cho bit to ra 9,5 tn ht/ha cy ng ly i mt

lng magi l 73 kg MgO[29]. Theo Nguyn Vn B, trung bnh vi nng

sut ht 6 tn/ha cy ng ht 33,5 kg MgO [4].Lu hunh tham gia vo mt s cht protit v mt s phc hp este.

Lu hunh tham gia vo qu trnh oxy ho kh, l mt nguyn t kch hot

s hnh thnh dip lc [28]. Theo Vin Ln - Kali Atlanta (M), to ra 10


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tn ng ht/ha cy ng ly i mt lng lu hunh l 34 kg [31]. Nguyn

Xun Trng (2000) to ra 9,5 tn ht/ha cy ng ly i mt lng lu

hunh l 21 kg S[29]. Theo Nguyn Vn B, trung bnh vi nng sut ht 6

tn/ha cy ng ht 16 kg S [4].Thiu lu hunh l cy chuyn sang mu vng a, gn l bin sang

mu vng, cc tri cy sinh trng km. Cc ging ng lai c tim nng

nng sut cao thng i hi nhiu lu hunh tng t nh photpho [9].

Thiu lu hunh thng xy ra trn t ct hoc t ngho cht hu c, t

xi mn ra tri mnh v biu hin trn cc l trn vi mu xanh nht, cy

chm pht trin [11].

Cy ng cn cc nguyn t vi lng vi lng rt t, nhng vai tr ca

chng i vi cy cn thit khng km g phn a lng. Chng c vai tr rt

ln i vi sinh trng v pht trin ca cy, gp phn nng cao cht lng

nng sn. Cy b thiu mt trong cc nguyn t vi lng s khng sinh

trng v pht trin c bnh thng. Bn phn vi lng thng mang li

hiu qu kinh t cao, do ch cn bn rt t [9].

Bo bo m cho hot ng bnh thng ca m phn sinh ngn cy;

xc tin qu trnh tng hp cc prtit, lignin v chuyn ho cc hidrat

cacbon, thc y qu trnh phn chia t bo. Bo y mnh vic ht canxi ca

cy v m bo cn i t l K:Ca trong cy [29]. Theo Vin Ln - Kali

Atlanta (M), to ra 10 tn ng ht/ha cy ng ly i 0,1 kg B [31].

Nguyn Xun Trng (2000) to ra 9,5 tn ht/ha cy ng ly i 0,19

kg B[29]. Thiu bo thng thy trong iu kin trng dy v cy ng c

bn phn y nhng vn thy cn ci hay ht lp.

Km thc y qu trnh hnh thnh cc hooc mn trong cy, lm tng tnh

chng chu hn v su bnh ca cy ng. Km lm tng kh nng tng hp cc

axit nucleic, protit, thc y vic s dng v chuyn ho m trong cy [9]. Theo

Vin Ln - Kali Atlanta (M), to ra 10 tn ng ht/ha cy ng ly i 0,6 kg


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km [31]. Theo Nguyn Xun Trng (2000) to ra 9,5 tn ht/ha cy ng

ly i 0,38 kg km[29]. Thiu km t c vi, t c kt cu km v ngho

cht hu c v t giu ln d tiu; bn nhiu phn ln cho ng c th dn n

vic thiu km nhng ni t km d tiu [11]. Cy b thiu km c th lm gim50% nng sut, mc d cy khng c biu hin ra triu chng bn ngoi [9].

Theo V Kim Bng (1991) x l ZnSO4 khng ch nh hng n nng sut

ht m cn lm tng hm lng axit amin khng thay th nh lyzim v triptophan

[28]. Hong H (1996) x l Zn cho ng thu c kt qu hm lng dip lc tng

s tng 10 - 16%, ch s din tch l (LAI) tng 10 - 32%, nng sut ng tng 6 -

13% so vi i chng khng x l [28]. Trn Th

ng (1995) s dng phn vilng Zn (mui sunphat) cho ng (VM - 1) lm tng nng sut t 107% so vi

i chng cng thc x l B, 126% cng thc x l vi Zn [28].

2.3. Kt qu nghin cu bn phn cho cy ng

2.3.1. Cc loi v dng phn bn cho ng

nh hng xu ca t c pH thp i vi ng c l ch yu l do Al3+di

ng cao. Khi t c pH 4,5 - 4,7 bn vi cho ng c hiu lc cao nu lng vi

trung ha 1/2 chua thu phn ca t. pH>5 khng cn phi bn vi, do

pH trn, Al3+di ng b c nh ht, khng cn gy tc hi g cho ng na.

Phn chung hay cc loi phn hu c khc l loi phn cn bn cho

ng trn mi loi t, nn s dng phn hoai mc. Cn u tin bn phn

hu c khi trng ng trn t ngho mn, t hai v la, t xm bc mu,

t thnh phn c gii nng [11].Dng phn m bn tt nht cho ng l amn nitrat hay sunphat amn

v ur cng tt nhng i hi qu trnh chuyn ho thnh amn nn cn trn

ln vo t trnh b bay hi.


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Bng 2.3. Hng dn s dng phn vi lng cho ng

Loi

nguyn tDng phn

Lng bn

(kg/ha)Phng php bn

ZnSO4. H2O 3,4 Lt; thc theo hngKm

Phc km 0,5 - 1,3 Thc theo hng

St sunphat 1 - 3% 300 - 400 lt/ha Phun qua lSt

St v c 30 Bn ngay khi c biu hin thiu st

ng sunphat 24 Bn lt theo hngng

ng sunphat 8 - 12 Bn trc khi gieo ht

MnSO4 20 Bn riMangan

MnSO40,7% 1 - 2 Phun qua l 30 v 60 ngy sau

khi gieo

Bo Borax 10 Lt trc khi gieo

Natri Molipen 1,25g/kg ht Trn vi ht gingMolipen

Natri Molipen 0,1% hun qua l 60 ngy sau khi trng


Dng phn ln thng bn cho ng l cc loi ln supe ho tan hayamn photphat nu nh khng c yu cu khc.

Loi kali thng bn cho ng l kali clorua va ph hp li r nht, trkhi t thiu lu hunh th c th dng kali sunphat p ng c K v S.

Cc loi phn vi lng cng thng c s dng cho ng nh bng trn.

Nu c iu kin nn s dng cc loi phn NPK chuyn dng cho ng [11].

2.3.2. Lng phn bn cho ng

Lng phn bn cho ng tu t trng, ging v mc ch sn xut

(tim nng, nng sut), ph t v c trnh thm canh.

Lng phn ho hc khuyn co bn cho ng mc thm canh cao

theo bng di (trn nn bn 10 - 20 tn/ha phn hu c).


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Bng 2.4. Lng phn bn cho ng thm canh

Lng bn (kg/ha)Loi t Loi ng

N P2O5 K2O

Ng lai 160 - 200 60 - 90 60 - 80

Ng thng 120 - 150 50 - 70 40 - 60t ph sa

Ng rau (thu non) 100 - 120 40 - 60 40 - 60

Ng lai 140 - 180 80 - 100 90 - 120

Ng thng 120 - 140 60 - 90 80 - 100t xm, ct

Ng rau (thu non) 100 - 120 40 - 60 40 - 60

Ng lai 160 - 200 80 - 100 80 - 100

Ng thng 120 - 150 60 - 80 40 - 60t vng

Ng rau (thu non) 100 - 120 40 - 60 40 - 60


Lng phn chung cn bn cho ng trung bnh l 8 - 10 tn/ha bn

c t 10 - 15 tn/ha cng tt. Bugai S.M. (1975) lm th nghim trong 7 nm

lin tc cho thy, bn 20 tn phn chung/ha lm tng nng sut ng trung

bnh 14,8 t/ha so vi khng bn. Th nghim trng i hc Nng nghip

Ucrain trong 6 nm lin tc cng bn lng phn chung nh trn lm

tng nng sut ng trung bnh 12,6 t/ha. Th nghim Polecki bn 20 tn

phn chung cho 1 ha lm tng nng sut ng 11,6 t/ha, cn khi bn 30 - 40

tn phn chung lm tng nng sut ng l 18,6 t/ha [2]. Tuy nhin, hiu lc

phn bn c bit cao khi bn phi hp phn hu c v v c. Cng theo kt

qu nghin cu 6 nm lin trng i hc Nng nghip Ucrain cho thy

bn 20 tn phn chung v 30 kg N, 30 kg P2O5v 30 kg K2O vo trc lc

cy t cho nng sut 53,5 t/ha [2].

Lng phn bn cho ng mt s nc khc nh sau: Tip Khc c

bn 120 kg N, 59 kg P2O5, 68 kg K2O/ha; Cng ho lin bang c (vng t


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tht) bn 150 - 200 kg N, 150 kg P2O5v 200 kg K2O/ha; Xnegan bn 120 kg

N, 60 kg P2O5v 60 kg K2O/ha; Camrun bn 120 kg N/ha [34]; n bn

N: 100 - 125 kg/ha; P: 60 kg P2O5/ha; K: 30 kg K2O/ha. Brazin liu lng bn

cho ng lai l 50 - 90 kg N, 50 - 80 kg P2O5v 30 - 60 kg K2O/ha [6].

Theo Hong Minh Chu (1998) Innxia ngi ta bn cho ging

ng lai vi lng 120 - 180 kg N, 45 - 60 kg P2O5, 30 - 60 kg K2O/ha cn

ging ng a phng th lng bn l 40 - 90 kg N, 30 - 45 kg P2O5, 0 - 30

kg K2O/ha. Thi Lan ngi ta bn phn cho cc ging ng lai vi lng

45 - 120 kg N, 45 - 60 kg P2O5, 0 - 60 kg K2O/ha. cn vi ging ng a

phng th lng bn l 30 - 40 kg N, 30 kg P2O5, 0 - 30 kg K2O/ha. Philippin ngi ta bn phn cho cc ging ng lai vi lng 90 - 140 kg N,

45 - 60 kg P2O5, 0 - 60 kg K2O/ha, cn vi ging ng a phng th lng

bn l 40 - 90 kg N, 30 kg P2O5[6].

Theo Zikriyaeua M.F., hiu lc ca phn ln chu nh hng ca t l

ln di ng trong t. Trn nn 120 kg N khi m t l ln di ng trong t ln

hn 53 mg/100g t, bn phn ln khng c hiu lc. Cn khi t l ln di ng

trong t l 21 mg/100g t th lng ln c hiu lc l 90 kg P2O5, loi t

ny cung cp m ln theo t l 4:3 lm nng sut tng n 50% [34].

Trepachep E.P., tng kt trn 180 rung ng vng Moxkva thy khi P2O5di

ng t t 15 - 40 mg/100g t (phn tch theo phng php Kiecxanop) th

khng cn bn phn ln. Theo Khaniep M.Kh., khi lng ln di ng trong

t t t 1,5 - 2,7 mg/100g t th bn n 120 kg P2O5vn cho bi thu cao

nht. Trn loi t ny hiu lc ca phn ln khng km hiu lc ca phn

m, r rng N, P2O5, K2O ph hp s cao hay thp th ch yu l do t l

cht dinh dng c trong t [34].

V kali, theo di nhiu th nghim ca cc tc gi Lin X c thy vn

hiu lc ca phn kali cng chu nh hng rt r ca lng kali trao i


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c trong t. Kt qu nghin cu ca Tulin A.S., Kliuchko P.E. cho thy khi

t c lng kali trao i (phn tch theo phng php Maslova) t 25 - 31,1

mg/100g t th vic bn phn kali khng c hiu lc d bn vi lng thp,

bn 45 kg K2O c khi li lm gim nng sut. Theo Hutinaep K.H. ch khilng kali trao i trong t khong 14,2 - 20,8 mg/100g t th bn phn

kali mi c hiu lc. Th nghim ca Niknova N.A., trn t c t l kali rt

thp 4 - 5 mg K2O trao i/100g t, hiu lc ca phn kali rt r. loi t

ny so vi trng chay th thy bn 60 kg K2O, 60 kg P2O5nng sut cng gn

bng bn 60 kg N, 60 kg P2O5 [34].

Tng hp cc kt qu nghin cu bn phn cho ng Vit Nam,

Nguyn Nh H cho bit: lng phn m thng bn cho ng t 100 150

kg N/ha, mc thm canh cao c th bn ti 200 kg N/ha. cc nc lng N

bn cho ng u cao hn 120 kg N/ha, nhiu nng dn t nng sut trn

12 tn ng ht/ha (trong iu kin ch ng ti) M bn ti 300

kgN/ha. Lng phn ln bn cho ng dao ng t 40 - 100 kg P2O5/ha,

thng bn 60 - 90 kg P2O5/ha. Lng bn kali cho ng tu thuc vo iu

kin c th dao ng t 40 - 120 kg K2O/ha, thng bn t 60 - 100 kg

K2O/ha. Khi ng c bn nhiu m hn th trong nhiu trng hp ng cngcn nhiu kali hn. Ng trng lm thc n chua cho gia sc cn rt nhiu kali,

t 200 - 300 kg K2O/ha [11].

Cc hng dn bn phn cho ng Vit Nam thng phn theo nhm

dng chung cho nhiu i tng t:

Trng Cng Tn v cng s khi bn phn cho ng lai CP - 888 s

dng lng phn bn (kg/ha): 100 N, 40 P2O5, 30 K2O cho 1 ha [27].

Theo quy trnh thm canh ca Vin Nghin cu Ng, i vi ging

ng MSB - 49, TBS - 2, HSB - 1 trng trong v ng bn: 5 - 7 tn phn

chung/ha, 100 - 120 kg N/ha, 60 kg P2O5/ha, 70 kg K2O/ha. Theo B Nng


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nghip v PTNT thm canh ging ng VM - 1 cn bn cho 1ha: 5 - 10 tn

phn chung, 120 kg N, 45 kg P2O5, 50 kg K2O/ha.

i vi ging ng lai nh: LVN - 10, LVN - 12, CP - 888, CP - 999,

Bioseed 9681 th mc u t phn bn cho 1 ha l: 10 - 15 tn phn chung,

140 - 160 kg N, 100 - 115 kg P2O5, 70 - 110 kg K2O/ha. Trng ng bu v

ng mc u t phn bn cho 1 ha nh sau: 8 - 10 tn phn chung, 140 -

160 kg N, 50 - 60 kg P2O5, 80 - 100 kg K2O/ha [17].

Theo Nguyn Vn B (2001) lng phn bn khuyn co cho ng phi

tu thuc vo t, ging ng, thi v. Ging c thi gian sinh trng di hn, c

nng sut cao hn cn phi bn lng phn cao hn. t chua phi bn nhiu

ln hn, t nh v v gieo trng c nhit thp cn bn nhiu kali hn [3].

Trong thc t cng c nhng khuyn co bn phn cho ng trong

nhng iu kin c th:

Theo Trn Hu Min (1987) phn bn v mt c lin quan mt

thit vi nhau. Trn t bi Sng Hng trng vi mt 5 vn cy/ha bn

100 N - 60 K2O - 30 P2O5/ha cho nng sut 30 t ht/ha. Nu trng vi mt

6 vn cy/ha:

- Bn lng 120 N - 90 K2O - 60 P2O5/ha cho nng sut 40 - 45 t ht/ha.



Nu bn vi lng cao hn i vi ging ng Vit Nam th nng sut

khng tng m gim dn, hiu qu phn bn thp [13].

Theo khuyn co ca Vin Khoa hc Nng nghip min Nam (

Trung Bnh, 2000), liu lng phn bn cho 1 ha ng vng ng Nam B

v Ty Nguyn l: 120 kg N, 90 kg P2O5, 60 kg K2O cho v h thu, cn v

thu ng c th tng lng K2O ln 90 kg [28].

Theo Trn Th D Tho v Nguyn Th Sm (2002), trn t xm ca vng


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ng Nam B, lng phn bn cho ng c hiu qu kinh t cao nht l 180 kg N,

80 kg P2O5, 100 kg K2O/ha (ging LVN-99) [28].

Theo L Qu Tng v Trn Vn Minh (2003) lng phn bn thch

hp cho ng lai trn t ph sa c duyn hi Trung b trong v ng xun

l 10 tn phn chung, 150 - 180 kg N, 90 kg P2O5, 60 kg K2O/ha, tiu tn

lng m t 22,6 - 28,8 kg N/tn ng ht, trong v h thu bn 10 tn phn

chung, 150 kg N, 90 kg P2O5, 60 kg K2O/ha [14].

Theo Nguyn Cng Thnh, Nguyn Th Cc v Dng Vn Chn (1995)

th ng bng sng Cu Long, mc kinh t ti u bn cho ng trn chn t

la vng Ty Sng Hu l 200 kg N, 100 kg P2O5, 100 kg K2O/ha [28].Nghin cu bc u ca Nguyn Vn Bo cho thy i vi ging ng

MSB - 49 v LS6 trong iu kin v xun H Giang ch nn bn mc 120

- 150 kg N, 50 kg P2O5, 50 - 60 kg K2O/ha. Cng theo tc gi trn, liu lng

bn phn thch hp i vi ng ph thuc vo nhiu yu t: ma v, t ai,

ging ng [2]. Lng phn bn khuyn co cho ng lai Trung tm Khuyn

nng H Giang: 8 - 10 tn phn chung, 120 - 140 kg N, 50 - 60 kg P2O5,

100 - 150 kg K2O/ha [18].

Liu lng khuyn co chung trn t bc mu cho ging ng chn

sm l: 8 - 10 tn phn chung, 120 - 150 kg N, 70 - 90 kg P2O5, 100 - 120

kg K2O/ha. Liu lng khuyn co trn t bc mu i vi ging ng chn

trung bnh v chn mun l: 8 - 10 tn phn chung, 150 - 180 kg N, 70 - 90

kg P2O5, 120 - 150 kg K2O/ha [3].

Tng kt th nghim bn phn cho ng lai vng ng Anh - H Ni(1996 - 1998), Nguyn Th Hng i n kt lun:

i vi ging ng lai v ng th ngng bn phn kinh t trn t bc

mu nh sau: 170 kg N, 90 kg P2O5, 90 - 150 kg K2O/ha [12].


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L Thanh Hi (2002) cho rng, trn t bc mu mc phn bn ph

hp v kinh t i vi ging ng lai HQ - 2000 l 100 kg N, 120 kg P2O5,

160 kg K2O/ha. Theo tc gi, vi liu lng ny tng lng ht NPK ln,

hiu sut s dng phn bn cao v nng cao c cht lng ht ng [28].

Theo Vin Th nhng - Nng ho: lng phn bn i vi ging ng

lai trn t bc mu (kg/ha) t nng sut cao l: 150 N, 90 P2O5, 120

K2O/ha; t nng sut kinh t l: 120 N, 120 P2O5, 90 K2O/ha [33].

Theo Nguyn Vn B kt qu ca m hnh bn phn cn i cho ng

ng trn t bc mu (ch yu l cn i N - K) cho thy bn phn cn i

mc kinh t l: 150 kg N, 90 kg P2O5, 90 kg (trn nn 8 tn phn

chung/ha) v mc t nng sut ti a l: 180 kg N, 90 kg P2O5, 120 kg

K2O ( trn nn 8 tn phn chung/ha). t nng sut v hiu qu kinh t

cao, c th bn cho ng ng trn t bc mu 150 - 180 kg N, 90 kg P2O5,

90 - 120 kg K2O trn nn 8 - 10 tn phn chung/ha [4].

Theo L Vn Cn Chu u, mc d cy trng khng c biu hin

thiu Mg nhng nu l t chua v thnh phn c gii nh, th ngi ta cng

bn Mg (5 10 kg MgO/ha) nht l t nh pht trin trn phin thch. Nu

cy c biu hin thiu Mg r rt, th ngi ta bn 40 60 kg MgO/ha. C th

phun ln l, tuy nhin bin php bn phn magi vo t vn l bin php bn

phn cn bn. Khi bn phi hp vi vi, ngi ta thng bn vi nhiu hn

Mg [5]. Theo Mineev V.G. trn t nh nn bn cho ng 60 - 70 MgO/ha [39].

Dierolf, T. khuyn co bn cho ng lai 20 - 40 kg MgO/ha [38].

Theo V Hu Ym hin nay, nhu cu bn lu hunh ngy cng tr nn

cp thit, cy trng ngy cng phn ng vi lu hunh. Do vy, cn lu tmn lu hunh nht l i vi h thng lun canh c cy b u v cy h

thp t l cc loi cy trng c nhu cu lu hunh cao. Th nghim cho thy

ngay c trn t bc mu Sc Sn H Ni hm lng lu hunh rt thp,

nu thay th ur bng sunphat m v thay tecrmophotphat bng supe ln


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n th tho mn v nhu cu lu hunh cho cy u tng l cy c

nhu cu lu hunh cao (Bi Th Vnh 1994) [35]. Dierolf, T. khuyn co bn

cho ng lai 10 - 20 kg S [38]. Theo Mineev V.G. lng S bn cho hu ht cc

cy trng trn t nh khong 50 - 60 kg/ha [39].Theo V Minh Kha vn bn Ca cn t ra i vi cc cy a chua,

chu chua v a kim.

Liu lng B thng dng Lin X c bn vo t: bn t 0,5

1,5 kg B/ha [39]. Theo Mineev V.G. lng bn cho ng 1 kg B/ha. Theo

Nguyn Xun Trng lng phn Bo bn cho ng 10 kg borax/ha [29].

Theo V Hu Ym bn vo t i vi B bn 15 30 kg Borat/ha.

Theo mt s tc gi nghin cu bn ZnSO4vi liu lng 0,4g cho

mt gc ng, cng tng nng sut ng t 5 10 t/ha [35]. Theo Mineev

V.G. lng bn cho ng 3 - 5 kg Zn/ha [39]. Theo Nguyn Xun Trng

lng phn phn km bn cho ng 3,4 kg ZnSO4/ha [29].

Tm li kt qu nghin cu v thc t s dng phn bn cho ng

trong v ngoi nc cho thy trong bn phn cho ng rt cn cung cp cc

cht dinh dng thit yu p ng nhu cu cn i dinh dng cho ng,

trong lng v t l phn N, P, K bn cn i cho ng trn t bc mu

kh thng nht. Vic cn thit bn thm cc cht dinh dng th cp cn

cha r cn thng qua nghin cu c th xc nh hiu lc v s cn thit

trong bn phn cn i cho ng trn t bc mu.

2.3.3. T l cc nguyn t NPK trong bn phn cho ng

Theo V Hu Ym, khi tnh t l cc nguyn t N, P, K bn cho ng

ngi ta thng da vo mt trong hai cn c sau: t l N - P2O5 - K2O trongsn phm thu hoch v kh nng cung cp N - P2O5 - K2O ca t. Cho nn

tu theo ti liu xut pht mi tc gi a ra mt t l NPK nht nh, c khi

trng nhau v c khi mu thun nhau [34].


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Phn tch ng khi t sn lng 100 bushel/acre, Wallace a ra lng

bn 160 N, 40 P2O5, 125 K2O Ib/acre vi t l N:P:K bn l 4:1:3. Theo Vin

Khoa hc Sn ng (Trung Quc), i vi ng xun hay ng h, t nng

sut 4500 - 5000 kg/ha cn cung cp cho ng 4,11 - 4,43 kg N, 1,18 - 1,51 kgP2O5v 3,51 - 3,78 kg K2O/t ht vi t l N:P:K thay i trong phm vi

4:1:3 v 3:1:3. Theo ti liu tng kt 12 im th nghim ca Vin t - Phn

tnh H Bc (Trung Quc, 1959) cho thy: cc mc nng sut ng t 3000 -

7500 kg/ha nng sut cng tng nu vic cung cp NPK tng thm, t l

N:P:K bn khong 2:1:3. Nghin cu Vonta Thng vi ging ng ngn

ngy cho thy lng NPK huy ng trn t feralit l: 1,44 kg N, 0,5 kg P2O5

v 1,5 kg K2O/ha v t l N:P:K huy ng li l 3:1:2 [34].

Vit Nam theo Trn Hu Min (1978) kt qu th nghim trn cc

loi t ph sa (1985 - 1987) cho thy ng t nng sut 30 - 40 t/ha cn

bn phn N, P, K theo t l 2:1:1, cn mun t nng sut cao hn t 50 - 70

t/ha cn bn theo t l 3:2:1 [9]. Theo T Vn Sn (1995) mun ng t

nng sut cao cn c t l N:P:K lc thu hoch l 5:2:3 [24].

Theo V Hu Ym (1975) [34] da vo hm lng NPK trong snphm thu hoch quyt nh t l N:P:K bn phn cho cy l khng hp l

v thc ra lng cht dinh dng trong sn phm thu hoch thay i nhiu

tu theo ging, kh hu, vn l nhng yu t nh hng su sc n tnh di

truyn nhiu hn l yu t t ai. Cng mt ging, trong hon cnh t ai

khc nhau, cy vn c gng m bo tnh n nh ca n trong t l cn i

dinh dng ni b. Kt qu th nghim lu nm i vi ng ti tri th

nghim ging Mironopski cho thy: do lng v t l phn N, P, K bn chong khc nhau sau 10 nm th nghim nng sut trung bnh t c rt khc

nhau, ni c lng phn bn bn tng gp i, nng sut thu hoch li

gim gn mt na. S d nh vy l v bn phn khng tnh n nhu cu dinh


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dng ca cy. Kt qu ca nhiu th nghim trn t podzon ng c (

Lin X c) cho thy t l cht dinh dng cn bn cho ng l 3:1:3, t

giu ln v kali th t l c th l 2:1:3 , khng nn bn phn theo t l 1:1:1

v nu trong cy t l ln gn vi m v kali th nng sut ng gim r rt.Trong khi Niknva N.A. cho rng loi t tho nguyn rng th t l

N:P:K nn phi hp l 1:1:1 hay 1,5:1:1 [34]. Tri vi ti liu trn Cng

ho Lin bang c ngi ta bn cho ng mt lng ln v kali rt cao. Theo

Seit, bn N, P2O5, K2O cho ng theo t l 1:1,5:1,2 s rt ngn c thi gian

chn ca ht. Nng cao t l ln, kali cng vi Mg trong bn phn lm tng

kh nng chng lm cho nng sut tng [34].

Theo Nguyn Vn B, kt qu ca m hnh bn phn cn i cho ng ng

trn t bc mu cho thy t nng sut kinh t bn phn theo N: P2O5: K2O

= 1: 0,6:0,6 (trn nn 8 tn phn chung/ha) cn t nng sut ti a

bnphn theo t l N: P2O5: K2O = 1:0,75:0,5 (trn nn 8 tn phn chung/ha) [4].

Nh vy c th ni bt k mt loi t no, i vi ng, m cng l

yu t c nh hng rt ln n nng sut. Cn ln v kali c bn hay khng

bn v bn bao nhiu ch yu phi da vo t l ln v kali d tiu c trong

t. Khi tnh t l nguyn t N:P:K ph hp bn cho ng thng da vo t

l dinh dng c trong t. V vy m t l N:P:K bn cho ng mi vng

cng khc nhau. Cc kt qu nghin cu v t l N:P:K bn cho ng trn t

bc mu c nhiu v kh thng nht.

2.3.4. Phng php bn phn cho ng

Tng hp t cc quy trnh hng dn bn phn cho ng Vit Nam

ca Nguyn Nh H (2006) cho thy trong bn phn cho ng thng chia

tng lng phn bn ra bn: lt v 2 - 3 ln bn thc, trong :

Bn phn lt cho ng ch yu dng hai loi phn hu c v ln


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bn lt, c th bn lt theo hai cch: ri u hay bn theo hng. Bn ri

u phn trn rung sau ba k, c u im l nhanh, tn cng

nhng phn khng tp trung vo gc, tc dng phn chm v hiu qu

thp. Bn phn theo hng l hnh thc bn phn sau khi lm t xong,phn c gii xung y rch, rch trc thnh hng, ri lp nh mt

lp t bt trc khi tra ht ging. Bn theo cch ny phn c bn tp

trung gn gc ng nn nhanh pht huy tc dng, nhng tn cng v

chm, nu ht ging tip xc trc tip vi phn khong, nht l phn

gy chua c th gy xt ht, thi mm v cht [11].

Bng 2.5. T l bn phn cho ng cc thi k

T l bn (%)

Thi k

N P2O5 K2O

Lt khi trng 25 - 30 55 - 60 20 25

10 - 15 ngy sau gieo (4 - 6 l) 40 - 45 20 - 25 25 30

35 - 40 ngy sau gieo (9 - 12 l) 30 - 35 20 45 50


Vic bn lt m v kali cho cy ng c nhng kin khc nhau: v

xt v nhu cu ca cy giai on u th cha cn nn c khuyn co

khng cn bn lt m v kali. Nhng do trng ng trong iu kin t cn

(kh), lng phn bn nhiu, cy c th chu c nng mui tan cao nn

bn lt 1/3 tng lng N v K2O v cn bn sm tho mn nhu cu m v

kali, thc y qu trnh cy non sinh trng. Do vy khi trng ng v ng

mun ng pht trin mnh rt ngn thi gian sinh trng, ngay thi gian

u c th bn lt mt lng NPK cao trong iu kin t c m 70 - 80%

v lp xa ht 15 - 20 cm. Nu bn lt nhiu m, ln v kali th phi chia ra


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mt phn bn ri trc khi gieo v phn cn li bn vo lc gieo [11].

Bn phn thc cho ng lm 3 t:

Bn thc t 1, khi cy ng c 3 - 4 l tht nhm gip cy ng pht trin

b r, chuyn t dinh dng ht sang dinh dng t t c tt, thng bn 1/3m + 1/3 kali. Pha phn vi nc ti cho cy hay ti bng nc gii pha

long. Nu t m c th bn trc tip vo t cch hai bn gc cy ng 5 - 7

cm ri u phn vo rch ri kt hp vun nh lp phn quanh gc ng.

gim cng bn phn khi c bn lt ln v kali c th khng bn thc 1 [11].

Bn thc t 2, khi cy ng c 7 - 9 l tht nhm thc y s pht trin

ca b r t, gip cho cy ng ht c nhiu cht dinh dng, pht trin

thn l, phn ho c quan sinh sn v chng . Thng dng 1/3 m + 1/3kali trn u vi phn bn vo rnh rch su 5 - 7 cm hai bn hng ng v

cch gc ng 10 - 15 cm, sau lp t vun vo gc [11].

Bn thc t 3, lc cy ng xon nn (10 - 15 ngy trc tr) tc dng tt

cho qu trnh phn ho bp v tr c, tung phn th tinh ca cy ng, to iu kin

cho thn l pht trin ti a, gi b l xanh lu quang hp nui ht. Dng ton

b lng phn cn li bn trc tip vo t nh t 2 v ko t vun ln cui [11].

Bng 2.6. Quy trnh bn phn NPK chuyn dng cho

cy ng min Nam

Thi kLoi phn

N:P2O5:K2O (%)Lng bn (kg/ha)

Lt 22 - 18 - 10 100 200

7 - 10 ngy sau mc 25 - 12 - 07 200 300

35 - 40 ngy sau mc 25 - 0 - 25 50 100



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Khi s dng cc loi phn NPK, ngoi bn lt, ln cn c th bn lm

nhiu t cng loi phn v c khc bng cc loi ln ho tan trong nc

theo yu cu ca cy. i vi phn m cn chia ra nhiu ln trong ch

trng t bn trc khi tr c. Kali chia ra nhiu ln nhng tp trung vo giaion trc phun ru [11].

Thc t sn xut cho thy vic chia phn bn thc vo 3 t tuy c

em li hiu qu phn bn cao hn nhng li tn nhiu cng bn phn hn,

nht l t bn th 3. V vy trong sn xut cn p dng phng php bn

phn vi 2 ln bn thc:

Theo Nguyn Xun Trng (2000) t l bn phn cho ng cc thi

k nh sau:- Lt trc khi trng: 25 - 30% N, 55 - 60% P2O5v 20 - 25% K2O.

- Thc khi ng 4 - 6 l: 40 - 45% N, 40 - 45% P2O5v 25 - 30% K2O.

- Thc khi ng 9 - 12 l: 30 - 35% N, 45 - 50% K2O [29].

Nguyn Th Hng, khi nghin cu phn bn cho ng lai vng ng

Anh - H Ni p dng k thut bn nh sau:

- Bn lt ton b phn chung, phn ln v 1/3 N.

- Bn thc: lc ng 7 - 9 l l 1/3 N + 1/2 K2O.Lc ng xon nn 1/3 N + 1/3 K2O [11].

Trung tm Khuyn nng tnh H Giang a ra cch bn cho ng lai nh sau:

- Bn lt ton b phn chung + phn ln.

- Bn thc: phn m + phn kali chia lm 2 ln bn.

+ Thc ln 1: lc ng 3 - 5 l, bn 40% N + 40% K2O.

+ Thc ln 2: lc ng 7 - 9 l, bn 60% N + 60% K2O cn li [18].

Theo Phm Th Ti v Trng ch (2005) a ra quy trnh bn cho

ng nh sau:

- Bn lt: ton b phn hu c, phn ln v 1/4 lng m.


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- Thc ln 1: khi cy ng 3 - 4 l bn 1/4 lng m v 1/2 lng kali.

- Thc ln 2: khi cy ng 7 - 9 l bn 1/2 lng m v 1/2 lng kali [26].

Theo ng Hng Dt (2003) quy trnh bn cho ng nh sau:

- Bn lt: ton b phn chung bn theo hng + ton b phn ln bn

theo hng hoc theo hc + 1/4 lng phn m + 2/3 lng kali.

- Bn thc ln 1: bn thc lc cy ng cao 10 - 15 cm, vi 2/4 lng

m + 1/3 lng phn ln.

- Bn thc ln 2: bn lc cy ng cao 60 - 70 cm, vi 1/4 lng m

cn li [8].

2.4. S cn thit phi bn phn cn i cho ng

Vit Nam l mt nc phi nhp khu ti 90 - 93% nhu cu v phn m,

30 - 35% nhu cu v phn ln v 100% nhu cu v phn kali. Th nhng thc t

li cho thy, do thiu hiu bit, nng dn s dng phn bn cn rt lng ph nn

hiu sut s dng phn m mi ch t 35 - 45%, phn ln v kali khong 50 -

60%. Trong cc gii php nng cao hiu lc phn bn, hn ch mt cht dinhdng th bn phn cn i gi vai tr ch o [32]. Theo FAO vic bn phn

khng cn i cho cy trng c th lm gim 20 - 50% hiu lc ca phn bn [3].

Bn phn cn i c hiu l cung cp cho cy trng ng cc cht dinh

dng thit yu, liu lng, t l thch hp, thi gian bn hp l cho tng i

tng cy trng, t, ma v c th m bo cho nng sut cao, cht lng

nng sn tt v an ton mi trng sinh thi. V nguyn tc mun m bo mt

h sinh thi bn vng th cy trng ht i bao nhiu, loi g u phi hon tr

cho t chng y cc cht dinh dng c th. Tt nhin, c nhng cht cy

trng ht rt nhiu song trong t li rt sn th khng cn thit phi bn [3].


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Bn phn cn i p ng c ti thiu 3 yu cu: bn ng v cc yu

t dinh dng cy trng cn, bn v lng v bn ph hp v t l cc

nguyn t . Bn phn cn i khng c ngha l phi cung cp cho cy trng

cc nguyn t dinh dng bng nhau v khi lng. c c s cho vic bn

phn cn i cn thit phi bit c kh nng cung cp dinh dng ca mi

loi t, nhu cu dinh dng ca mi loi cy trng v s ph thuc ca mi

yu t vo tng iu kin thi tit cng nh ch canh tc c th [3].

Bn phn cn i v hp l l thc hin 5 ng: ng loi phn, bn

ng lc, bn ng i tng, ng thi tit, ma v v bn ng cch.

Bn phn cn i, hp l c nhng tc dng tt sau: n nh, ci to

ph nhiu ca t, bo v t chng ra tri, xi mn, tng nng sut v

phm cht nng sn. Bo v ngun nc, hn ch kh thi c hi gy

nhim mi trng [9].

Trng ng trn t ct, t xm, t bc mu cn quan tm bn c

N, P, K v cc phn trung lng, vi lng, phn hu c. Bn phn cn i

cho cy trng l mt bin php bo v thc vt rt c hiu qu, v to cho cy

trng pht trin kho mnh, c sc chng chu su bnh hi cao, gip t

nng sut cao phm cht tt. Bn phn cn i cho cy trng l mt phn

quan trng, khng th thiu ca IPM [11].

Theo Nguyn Vn B (2001) bn phn cn i m - kali cho ng c hiu

lc cao hn nhiu so vi la. Bi thu do bn phn cn i (trung bnh ca liu

lng bn m) c th t 33 t/ha trn t ph sa Sng Hng, 37,7 t/ha trn t

bc mu, 11,7 t/ha trn t vng. Xt v hiu qu kinh t th bn phn cn i

cho ng trn t bc mu, t xm c li nhiu hn t ph sa v t ct vng [3].


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Bng 2.7. Hiu qu bn phn cn i cho ng

S kg ng thu c t 1 kg

phn bn nguyn chtH s li

Cng thct ph sa t bc mu t ph sa

t bc

mu

NP 11,2 0,05 2,47 0

NPK 11,0 12,6 2,80 3,20

Ngun: dn theo Nguyn Vn B [3]

Bn tng loi phn ring r hiu lc khng cao, bn kt hp th hiulc tng ng k, cao hn c tng hiu lc ca mi loi phn bn [3].

Kt qu nghin cu phn bn cho ng ng trn t ph sa Sng Hng cho

thy: nu ch bn m th hiu qu u t thp, h s li ch t 1,98 nu bn kt

hp m - ln th h s li tng ln 2,47 cn nu bn y m - ln - kali th h

s li l 2,80. Khi lng m bn cng cao th cng cn thit phi bn cn i.

Bng 2.8. Cn i dinh dng cho ng trn t ph sa Sng Hng

Cng thc

bn

Nng sut

t/ha

Bi thu

t/ha

Hiu qu, kg ng/kg dinh

dng nguyn cht

H s

li

Khng bn

N

NP

K

NK

NPK

4,5

14,8

28,0

4,5

21,3

37,5

-

10,3

23,5

0

16,8

33,0

-

8,6

11,2

0

8,0

11,0

-

1,98

2,47

0

2,25

2,80

Ngun: dn theo Nguyn Vn B [3]


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Bn phn cn i v c - hu c cho ng cng rt quan trng v phn hu

c ngoi tc dng cung cp mt phn cht dinh dng cn li ci thin tnh cht

vt l t gip cy sinh trng tt hn. Phn chung rt tt cho ng, song khng

bn phn khong, c bit l m th hiu lc ca phn chung cng rt thp.Ch bn phn chung, hiu qu t 30 kg ng/tn phn chung, cn nu bn kt

hp vi m th hiu sut tng ln 126 kg ng ht/tn phn chung [3].

Vic bn phi hp cc dng phn c cha lu hunh cng nh phn c

cha km u gp phn cn i nhu cu ca cy v tng nng sut ng ng

tin cy. t nng sut ng cao v n nh, ng cn c bn cn i, c

bit l gia cc nguyn t NPK [3].

bt k loi t no, i vi ng m cng l nhn t c nh hng

rt ln n nng sut, cn ln v kali bn bao nhiu da vo hm lng ln

v kali d tiu c trong t [11].

Trng ng cng cn quan tm bn thng xuyn cc dng phn cha S

nh supe ln v s dng phn vi lng Zn cho ng m bo ng cho nng

sut cao, phm cht tt, c hiu lc chung ca phn bn cao v hiu qu sn

xut cao [11].

Trng ng trn t ct, t xm, t bc mu cn quan tm bn c

N, P, K v cc phn trung, vi lng, phn hu c cn trn t cn ch

bn ln v kali.

Trn cc loi t ngho dinh dng nh t xm, t ct cn bn nhiu

ln v kali hn so vi ph sa, t bazan. Trn cc loi t bc mu, t

xm, t ct bn phn kali c tc dng tng nng sut r rt [11].Nhng rung trng ng s dng t phn hu c hay b thiu cc nguyn

t vi lng, s dng phn vi lng bn l rt tt. Phn vi lng c th dng

bn vo t, trn vi cc loi phn khc bn, phun ln l cy [9].


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Ng lai cn bn nhiu phn hn ng thng, ng thng cn bn

nhiu hn ng thu non (ng rau, ng bao t).

Theo nguyn Vn B (2003) kt qu ca m hnh bn phn cn i

cho ng ng trn t bc mu (ch yu l cn i N - K) cho thy bn phn

cn i cc mc u t phn bn t nng sut kinh t v nng sut ti

a u cho nng sut cao hn nhiu so vi cch bn ca nng dn va c u

t phn bn thp va khng cn i dinh dng (120 kg N, 90 kg P2O5, 60 kg

K2O = 1: 0,5:0,67 trn nn 8 tn phn chung/ha). Nh bn phn cn i

nng sut ng tng 27 - 88% vi li rng 2,4 - 4,7 triu ng/ha so vi cch

bn ca nng dn [4].


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3. Ni dung v phng php nghin cu

3.1. Ni dung nghin cu ca ti

- nh gi nh hng ca bn ring r v phi hp cc cht dinh dng

S, Ca, Mg, B, Zn (trn nn N, P, K) n sinh trng pht trin, su bnh hi,

cc yu t cu thnh nng sut, nng sut ca ng trn t bc mu.

- nh gi nh hng ca cc cng thc bn phn ti vic tch lu N,

P, K vo trong cy ng thi k thu hoch v cht lng sn phm.

3.2. Phng php nghin cu

3.2.1. Cng thc th nghim t mc ch ca ti, th nghim bao gm cc cng thc di y:

Cng thc th nghim

CTTN Ni dung cng thc th nghim (kg/ha) Phng php bn

1 10 tn phn chung - nn

2 Nn + 135N 90P2O5100K2O Nn 2

3 Nn 2 + 30S

4 Nn 2 + 120CaO

5 Nn 2 + 40MgO

6 Nn 2 +10Borax

7 Nn 2 + 3,4ZnSO4.H2O

8 Nn + 135N 90P2O5100K2O *

9 Nn + 120N 81P2O588K2O 107CaO 36MgO 27S

10 Nn + 135N 90P2O5100K2O 120CaO 40MgO 30S

11 Nn + 150N 101P2O5110K2O 133CaO 44MgO 33S

12 Nn 2 + 120CaO 40MgO 30S 3,4ZnSO4 10Borax

Bn lt: Ton b

phn chung cng

vi 65% P2O5+

22% N + 18% K2O

Bn thc 1: 45%

N + 20% P2O5+

36% K2O

Bn thc 2:

33% N + 15% P2O5+ 46% K2O


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* Bn lt ton b phn chung, phn ln cng vi 25% N v 25% K2O;

bn thc 1: 40% N + 35% K2O; bn thc ln 2: 35% N + 40% K2O.

3.2.2. Phng php b tr th nghim

Th nghim c b tr theo khi ngu nhin, 3 ln lp li.

Din tch th nghim: 12 m2.

3.2.3. K thut trng, chm sc

- Ging ng th nghim LVN - 4, lng ht ging 15 kg/ha.

- Thi v: v ng nm 2006.

- Lm t: t c cy ba k, nht sch c di, ln lung rng

khong 80 - 90 cm, cao 20 - 25 cm.

- Mt v khong cch: hng cch hng 70 cm, cy cch cy 28 cm.

Mt trng 50.000 cy/ha (1.800 cy/so).

- Phng php bn phn: theo cng thc th nghim.

- Chm sc: thng xuyn xi xo lm c, ti nc cho ng.

+ Dm ng: khi cy con thng hay b su xm cn hi nn phi tin

hnh dm nhng cy b mt m bo mt .

- Su bnh: cy ng thng xuyn mc mt s loi su bnh chnh nhsu xm, su c thn, bnh m l nh, bnh kh vn, bnh phn en Do

phi thng xuyn theo di c bin php phng tr c hiu qu.

3.2.4. Cc ch tiu theo di

- Cc ch tiu v sinh trng: chiu cao cy, s l cc giai on sinh

trng (3 - 4 l tht, 7 - 9 l tht, tr c v thu hoch). Mi th nghim theo

di trn 10 cy c nh du.

+ Cch o: o t gc st mt t n nh l c chiu cao ln nht.

+ m s l.- Cc yu t cu thnh nng sut:

+ S bp/cy: m s bp ca 10 cy trong 1 . Sau ly kt qu trung bnh.

+ S ht/bp: m s ht ca tng bp. S ht c tnh bng s ht


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trung bnh ca 10 bp/.

+ Trng lng 1000 ht (g)

- Nng sut thc thu

Thu hoch ton b thn l v bp c trn th nghim cn ti tnhnng sut bp, thn l v tng sinh khi. Trong 1 th nghim ly thn, l,bp ca 10 cy c nh du (cn bp ring, thn l ring sau phi kh tht tnh t l hao, dng tnh nng sut kh, tnh cc yu t cu thnh nngsut v ly mu phn tch).

- Theo di nh hng ca cc ch bn phn n mt su/m 2vmc hi ca su bnh.

+ Phng php theo di theo phng php hng dn ca IRRI.

3.2.5. Cc ch tiu phn tch- Phn tch t trc th nghim: pHKCL, OM, N, P, K, Ca, Mg, S, Zn, B

tng s v d tiu.

- Phn tch hm lng N, P, K trong cy ng v ht ng thi k thu hoch.

- Phn tch hm lng tinh bt trong ht ng.

* Phng php phn tch

+ Xc nh N tng s bng phng php Kjendhal (theo Bremner).

+ Xc nh P tng s trong t bng quang ph k.+ Xc nh P d tiu bng phng php Oniani.+ Xc nh K tng s bng phng php quang k ngn la.+ Xc nh K d tiu bng phng php Maslopva.+ Xc nh Ca d tiu bng phng php chun vi TrilonB.+ Xc nh Mg d tiu bng phng php chun vi TrilonB.+ Xc nh S d tiu bng phng php Trilon B.+ Xc nh Zn d tiu bng phng php dng dch chit HCl 0,1N.+ Xc nh pH bng my o pH metter.

+ Xc nh OM theo Walkley - Black.+ Xc nh tinh bt bng phng php It.

3.2.6. Phng php x l thng k s liu

X l kt qu th nghim theo chng trnh phn mm IRRISTAT.


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4. Kt qu nghin cu v tho lun

4.1. Kt qu phn tch t trc th nghim

Bng 4.1. Mt s ch tiu nng ho ca t nghin cu

Ch tiu n v tnh S lng Ch tiu n v tnh S lng

pHKCL 4,6 K2O mg/100g t 4,7

OM (%) 1,4 Ca2+ ll/100g t 1,12

N (%) 0,06 Mg2+ ll/100g t 3,09

P2O5 (%) 0,06 SO42- ll/100g t 1,12

K2O (%) 0,42 Zn2+ mg/kg t 0,24

P2O5 mg/100g t 6,1

Kt qu phn tch t trc th nghim c trnh by bng 4.1 cho thy:

t th nghim trng ng c pH chua, ngho mn, ngho cc cht dinh

dng tng s v d tiu.

Nh vy mun trng ng t nng sut cao, phm cht tt trn t bc

mu cn phi ch bn y v cn i cc cht dinh dng.

4.2. nh hng ca bn thm cc cht dinh dng th cp n mt s

ch tiu sinh trng ca cy ng

4.2.1.nh hng ca bn thm cc cht dinh dng th cp n s pht

trin chiu cao cy ng

Chiu cao cy ng l do c tnh ging quyt nh. Tuy vy cc yu t

mi trng: nhit , m, cht dinh dng cng c nh hng n chiu

cao cy ng trong phm vi nht nh. Kt qu nghin cu nh hng ca

phn bn ti s pht trin chiu cao ca cy ng c trnh by bng 4.2.


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Bng 4.2. nh hng ca bn thm cc cht dinh dng th cpn chiu cao cy ng qua cc thi k sinh trng

Chiu cao cy cc thi k sinh trng (cm)CTTN

3 - 4 l tht 7 - 9 l tht Tr c Thu hoch

1 27,9 70,5 208,7 210,2

2 28,6 90,6 267,0 268,0

3 28,6 92,7 270,7 270,9

4 29,0 93,9 271,2 271,5

5 28,5 92,8 268,9 270,5

6 28,8 90,9 267,6 269,9

7 28,7 91,5 267,0 271,8

8 28,6 90,5 268,1 268,2

9 28,3 91,1 267,9 270,0

10 29,1 91,5 268,1 272,2

11 29,1 91,5 268,7 272,3

12 28,7 91,1 268,4 271,6

Kt qu bng 4.2 cho thy:

thi k 3 4 l cc ch bn phn khc nhau lm tng chiu cao

cy ng t 0,4 1,2 cm so vi i chng khng bn phn khong (CT 1), cc

liu lng phn bn t gy nh hng n chiu cao cy do y l thi k cy

ng sinh trng v pht trin rt chm. Nhng t thi k 7 9 l n tr c v

thu hoch th s nh hng ca phn bn n s pht trin chiu cao cy ng

l rt r rt. Chiu cao cy ng ca cc cng thc c bn phn tng so vi

cng thc khng bn phn (CT 1), thi k 7 9 l t 20 23,4 cm, thi k

tr c t 58,3 62,5 cm v thi k thu hoch t 57,8 62,1 cm. nh hng

ca phn bn n s pht trin chiu cao cy ng rt r vo thi k tr c.


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So snh cc cng thc c bn b sung thm 30S, 120CaO, 40MgO,

10Borax, 3,4ZnSO4.H2O trn nn 135N, 90P2O5, 100K2O/ha (CT 3, 4, 5, 6, 7)

vi cng thc bn 135N, 90P2O5, 100K2O/ha (CT 2) thy t c s chnh lch

v chiu cao cy cc thi k sinh trng u ca cy ng. Nhng thi kt tr c c s chnh lch chiu cao ng k, thi k thu hoch cc cng

thc c bn thm cc cht dinh dng trung, vi lng cao hn 1,9 - 3,8 cm

so vi CT 2.

So snh hai cng thc c cng mt lng bn 135N, 90P2O5, 100K2O/ha

(CT 2, 8), nhng cch bn khc nhau, thy khng c s chnh lch v chiu cao

cy cc thi k sinh trng ca cy ng.

So snh cng thc bn 135N, 90P2O5, 100K2O (CT 2) vi cc cng thc

c bn cc cht trung lng cc mc khc nhau (CT 9, 10, 11) v c vi

lng (CT 12) t giai on ng tr c n thu hoch ca cy ng cho thy vic

phi hp ng thi cc cht dinh dng trn lm tng r chiu cao cy ng.

4.2.2.nh hng ca bn thm cc cht dinh dng th cp n s ra l

ca cy ng

S l cng do c tnh ging quyt nh, song cc yu t mi trng:

nhit , m, cht dinh dng cng nh hng n s l ca cy ng

trong phm vi nht nh. Kt qu nghin cu nh hng ca phn bn n s

ra l ca cy ng c trnh by bng 4.3.


thi k 3 4 l, cc ch bn phn khc nhau lm tng l ng t

0,2 0,5 l so vi cng thc i chng khng bn phn khong (CT 1).

Nhng thi k 7 9 l v tr c th ch bn phn khc nhau lm tng

s l tng ng l t 0,8 1,2 l v 0,7 1,3 l so vi cng thc i chng

khng bn phn (CT 1).


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Bng 4.3. nh hng ca bn thm cc cht dinh dngth cp n s l cy ng qua cc thi k sinh trng

S l ca cy ng cc thi k sinh trngCTTN

3 - 4 l tht 7 - 9 l tht Tr c Thu hoch

1 3,2 7,0 12,5 12,5

2 3,5 7,8 13,2 13,3

3 3,5 8,0 13,7 13,7

4 3,5 8,0 13,6 13,6

5 3,4 7,9 13,5 13,6

6 3,5 7,9 13,5 13,5

7 3,5 8,0 13,5 13,6

8 3,4 8,0 13,2 13,39 3,4 8,0 13,4 13,4

10 3,7 8,2 13,8 13,8

11 3,7 8,2 13,8 13,8

12 3,7 8,1 13,7 13,7



vi cng thc bn 135N, 90P2O5, 100K2O/ha (CT 2) thy thi k 3 4 l lkhng c s chnh lch nhau v s l, cn thi 7 9 l, tr c v thu hoch

th c s chnh lch nhau v s l nhng khng ng k. Nh vy l khi c

b sung thm ring r cc cht dinh dng trung, vi lng (CT 3, 4, 5 , 6, 7)

th t c nh hng n s l ca cy ng.


(CT 2, 8), nhng cch bn khc nhau, thy khng c s chnh lch v s l

cc thi k sinh trng ca cy ng.So snh cng thc bn 135N, 90P2O5, 100K2O/ha (CT 2) vi cng thc

bn 135N, 90P2O5, 100K2O, 120CaO, 40MgO, 30S/ha (CT 10) thy CT 10 c


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s l nhiu hn CT 2 cc thi k 3 4 l, 7 9 l, tr c v thu hoch l 0,2

l, 0,4 l, 0,6 l v 0,5 l.

So snh hai cng thc bn 135N, 90P2O5, 100K2O, 120CaO, 40MgO,

30S/ha (CT 10) v cng thc bn 135N, 90P2O5, 100K2O, 54CaO, 40MgO,20S, 3,4ZnSO4, 10Borax/ha (CT 12) thy s l ca CT 10 cao hn CT 11

cc thi 7 9 l, tr c v thu hoch u l 0,1 l.

So snh cc cng thc 9, 10, 11 thy s l ca CT 10 cao hn s l ca

CT 9 cc thi k 3 4 l, 7 9 l, tr c v thu hoch tng ng l 0,3 l,

0,2 l, 0,4 l v 0,4 l. CT 10 v CT 11 c s l l tng ng nhau.

4.3. nh hng ca bn thm cc cht dinh dng th cp n cc yu

t cu thnh nng sut v nng sut ng

4.3.1. nh hng ca bn thm cc cht dinh dng th cp n s ht

trn bp

Bng 4. 4. nh hng ca bn thm cc cht dinh dng th cp ncc yu t cu thnh nng sut v nng sut ng

Cc yu t cu thnh nng sutCTTN

S ht/bp P1000 ht (g)Nng sut

kg/ha1 201,6 281,9 25102 344,7 319,7 49053 355,1 327,8 51984 352.3 329,4 52505 352,0 326,0 52906 349,1 325,7 51507 351,2 326,3 51658 345,5 321,1 5005

9 349,1 326,9 511510 355,0 332,5 540511 366,6 334,7 551012 367,5 337,9 5525

LSD(5%)

154,5


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Cng thc 1 c s ht/bp thp nht 201,6 ht, cng thc 12 c s ht/bp

cao nht 367,5 ht. Chnh lch v s ht/bp ca hai cng thc ny l 165,9 ht.

Ch bn phn khc nhau nh hng r rt n s lng ht, cth l lm tng t 143,1 165,9 ht/bp so vi cng thc i chng khng

bn phn khong (CT 1).

Cc cng thc c b sung thm 30S, 120CaO, 40MgO, 10Borax,

3,4ZnSO4.H2O trn nn 135N, 90P2O5, 100 K2O/ha (CT 3, 4, 5, 6, 7) c s

ht/bp cao hn s ht/bp ca cng thc bn 135N, 90P2O5, 100K2O/ha (CT

2) l 10,4 ht, 7,6 ht, 7,3 ht, 4,4 ht v 6,5 ht.

So snh hai cng thc c cng mt lng 135N, 90P2O5, 100K2O/ha(CT 2, 8), cch bn khc nhau, thy CT 8 c s ht/bp cao hn s ht/bp

ca CT 2 l 0,8 ht. Nh vy vi cng mt lng bn nhng cch bn khc

nhau t c nh hng n s ht/bp.

So snh cng thc bn 135N, 90P2O5, 100K2O/ha (CT 2) vi cng thc


s ht/bp cao hn CT 2 l 10,3 ht. iu ny cho thy khi bn phn cn i

v y cht dinh dng lm tng mnh s ht/bp ca cy ng.So snh hai cng thc bn 135N, 90P2O5, 100K2O, 120CaO, 40MgO,

30S/ha v cng thc bn 135N, 90P2O5, 100K2O, 120CaO, 40MgO, 30S,

3,4ZnSO4, 10Borax/ha (CT 10, 12) thy cng thc 10 c s ht/bp t hn s

ht/bp ca cng thc 12 l 12,5 ht.

So snh cc cng thc 9, 10 v 11 thy s ht/bp ca cng thc 10

cao hn s ht/bp ca cng thc 9 l 5,9 ht v thp hn cng thc 11 l

11,6 ht. Nh vy khi gim lng N, P, K bn th s ht/bp gim v ngcli khi tng lng N, P, K bn th s ht/bp cng tng.

Tm li, khi bn y v cn i cc cht dinh dng t a lng

n vi lng c nh hng rt r rt n s ht/bp ca cy ng.


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4.3.2. nh hng ca bn thm cc cht dinh dng th cp n trng

lng 1000 ht ng


So snh cc cng thc bn phn khong vi i chng khng bn (CT 1)

thy bn phn khong lm tng trng lng 1000 ht t 37,8 56,0g.

Cc cng thc c bn b sung thm 30S, 120CaO, 40MgO, 10Borax,

3,4ZnSO4.H2O trn nn 135N, 90P2O5, 100K2O/ha (CT 3, 4, 5, 6, 7) c trng

lng 1000 ht cao hn cng thc bn 135N, 90P2O5, 100K2O/ha (CT 2) l

8,1g; 9,7g; 6,3g; 6,0g v 6,6g cho thy tc dng lm tng trng lng 1000

ht ca vic bn thm.So snh hai cng thc c cng mt lng bn 135N, 90P2O5,

100K2O/ha (CT 2, 8) thy CT 8 c trng lng 1000 ht cao hn CT 2 l

1,4g. Vy vi cng mt lng bn nhng cch bn khc nhau t nh hng

n trng lng 1000 ht.



trng lng 1000 ht cao hn CT 2 l 12,8g. Vy khi c bn b sung Ca,Mg, S th trng lng 1000 ht ng tng ln rt r rt.

So snh cng thc bn 135N, 90P2O5, 100K2O, 120CaO, 40MgO,

30S/ha (CT 10) vi cng thc bn 135N, 90P2O5, 100K2O, 120CaO, 40MgO,

30S, 3,4ZnSO4, 10Borax/ha (CT 12) thy CT 10 c trng lng 1000 ht t

hn CT 12 l 5,4g. Vy cng thc c bn y cc nguyn t t a

lng n vi lng c nh hng r n trng lng 1000 ht.

So snh cc cng thc 9, 10, 11 thy CT 10 c trng lng 1000 ht

cao hn CT 9 l 5,6g v CT 10 c trng lng 1000 ht thp hn CT 11 l

2,2g. Nh vy, khi gim lng N, P, K bn th trng lng 1000 ht gim v

ngc li khi tng lng N, P, K bn th trng lng 1000 ht cng tng.


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4.3.3.nh hng ca bn thm cc cht dinh dng th cp ti nng sut

ng

Kt qu bng 4.4 cho thy cc ch bn phn khc nhau lm

tng nng sut ng t 2395 3015 kg/ha (tng 95,4 120,1%) so vi cngthc i chng khng bn phn khong (CT 1).

Bn b sung thm 30S, 120CaO, 40MgO, 10Borax, 3,4ZnSO4.H2O

trn nn 135N, 90P2O5, 100K2O/ha (CT 3, 4, 5, 6, 7) c nng sut cao hn

cng thc bn 135N, 90P2O5, 100K2O/ha (CT 2) l 393 kg/ha (tng 5,97%),

345 kg/ha (tng 7,03%), 385 kg/ha (tng 7,84%), 245 kg/ha (tng 4,99%),

260 kg/ha (tng 5,30%). Nh vy cc cng thc c b sung thm cc cht

dinh dng (CT 3, 4, 5, 6, 7) u c nh hng r ti nng sut ca ng.


(CT 2, 8) thy cng mt lng bn nhng cch bn khc nhau t nh hng n

nng sut ng.



nng sut cao hn rt r so vi CT 2 l 500 kg/ha (tng 10,2%).



30S, 3,4ZnSO4, 10Borax/ha (CT 12) thy CT 10 c nng sut thp hn CT 12

khng r (120 kg/ha). Vy cng thc c bn thm vi lng (CT 12) c

nng sut tng khng ng k so vi CT 10.

So snh cc cng thc 9, 10, 11 thy CT 10 c nng sut cao hn r so

vi CT 9 (290 kg/ha - 5,67%) v thp hn CT 11 khng r (105 kg/ha). Nh

vy, khi gim lng N, P, K bn th nng sut gim v ngc li khi tng

lng N, P, K bn th nng sut tng khng ng k (1,94%). iu ny cho

thy rt nn bn phn cho ng nh CT 10.


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4.4. nh hng ca bn thm cc cht dinh dng th cp n tnh

hnh su bnh hi ng

4.4.1.nh hng ca bn thm cc cht dinh dng th cp n tnh hnh

su hi ng

Bng 4.5. nh hng ca bn thm cc cht dinh dng th cpn tnh hnh su, bnh hi ng

Mt su (con/m2) T l cy bnh (%)CTTN

Thi k tr c Thi k chn Thi k tr c Thi k chn

1 0,5 0,4 9,2 10,1

2 1,2 0,9 11,6 9,9

3 1,1 0,9 11,5 9,6

4 1,0 0,7 11,2 9,3

5 1,2 0,9 11,4 9,4

6 1,2 0,9 11,6 9,7

7 1,1 0,7 11,5 9,4

8 1,2 0,8 11,7 9,8

9 0,4 0,2 8,9 7,5

10 0,3 0,1 5,6 3,7

11 0,4 0,2 6,1 4,2

12 0,4 0,2 6,6 4,2




vi cng thc bn 135N, 90P2O5, 100K2O/ha (CT 2) thi k tr c v chn


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cho thy cc cng thc c bn thm tng cht dinh dng th cp c xu

hng lm gim mt su hi nhng khng nhiu ( thi k tr c CT 3, 4,

7 c mt su thp hn CT 2 tng ng l 0,1 con; 0,2 con; 0,1 con; thi

k chn thy CT 4, 7 c mt su thp hn CT 2 u l 0,2 con).

So snh hai cng thc c cng mt lng bn 8 10 tn phn chung,

135N, 90P2O5, 100K2O/ha (CT 2, 8) thy thi k tr c c mt su l

nh nhau. thi k chn CT 8 c mt su thp hn CT 2 l 0,1 con. Nh

vy vi cng mt lng bn nhng cch bn khc nhau rt t nh hng n

mt su cc thi k sinh trng ca cy ng.

So snh cng thc bn 135N, 90P2O5, 100K2O/ha (CT 2) vi cng thcbn 135N, 90P2O5, 100K2O, 120CaO, 40MgO, 30S/ha (CT 10) thy c hai

thi k tr c v chn, CT 10 c mt su thp hn rt nhiu so vi CT 2 l

0,9 con; 0,8 con. iu ny chng t rng khi bn cn i v y cc cht

dinh dng th kh nng khng su ca cy ng l rt cao.


30S/ha (CT 10) vi cng thc bn 135N, 90P2O

5, 100K

2O, 120CaO, 40MgO,

30S, 3,4ZnSO4, 10Borax/ha (CT 12) thy c hai thi k tr c v chn CT

10 c mt su thp hn CT 12 u l 0,1 con.

So snh cc cng thc 9, 10, 11 thy c hai thi k tr c v chn CT

10 c mt su thp hn CT 9, 11 u l 0,1 con. cng thc 10 bn 135N,

90P2O5, 100K2O, 120CaO, 40MgO, 30S/ha c mt su (con/m2) thp nht,

thi k tr c l 0,3 con/m2, thi k chn l 0,1 con/m2. Nh vy khi bn phn

cn i v y cht dinh dng, th cy sinh trng v pht trin khe. Do

mt su cc thi k l rt thp. iu ny chng t rng khi bn phn

cn i lm gim mt su hi trn cy ng.


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4.4.2. nh hng ca bn thm cc cht dinh dng th cp n tnh hnh

bnh hi ng


So snh cc cng thc c bn b sung thm 30S, 120CaO, 40MgO,10Borax, 3,4ZnSO4.H2O trn nn 135N, 90P2O5, 100K2O/ha (CT 3, 4, 5, 6, 7)

vi cng thc bn 135N, 90P2O5, 100K2O/ha (CT 2) thi k tr c v chn

cho thy cc cng thc c bn thm tng cht dinh dng th cp c lm

gim t l cy b bnh nhng khng nhiu (CT 3, 4, 5, 7) c t l bnh thp

hn CT 2 tng ng l 0,1%; 0,4%; 0,2% v 0,1%. CT 2, 6 c t l bnh

ngang nhau. thi k chn thy CT 3, 4, 5, 6, 7 c t l bnh thp hn CT 2

l 0,3%; 0,6%; 0,5%; 0,2% v 0,5%.So snh hai cng thc c cng mt lng bn 135N, 90P2O5,

100K2O/ha (CT 2, 8) thy thi k tr c CT 8 c t l bnh cao hn CT 2 l

0,1% v ngc li thi k chn CT 2 c t l cy bnh cao hn CT 8 l

0,1%. Nh vy vi cng mt lng bn nhng cch bn khc nhau rt t nh

hng n t l bnh hi ng.


bn 135N, 90P2O5, 100K2O, 120CaO, 40MgO, 30S/ha (CT 10) thy c hai

thi k tr c v chn, CT 10 c t l cy b bnh thp hn rt nhiu so vi CT

2 l 6,0%; 6,2%. iu ny chng t rng khi bn cn i v y cc cht

dinh dng th kh nng khng bnh ca cy ng l rt mnh.



30S, 3,4ZnSO4, 10Borax/ha (CT 12) thy hai thi k tr c v chn CT 10

c t l bnh thp hn CT 12 l 1,0% v 0,5%.

So snh cc cng thc 9, 10, 11 thy thi k tr c CT 10 c t lbnh thp hn CT 9, 11 l 3,3% v 0,5%. thi k chn CT 10 cng c t l

bnh thp hn CT 9, 11 l 3,8% v 0,5%. Nh vy cng thc 10 bn, 135N,

90P2O5, 100K2O, 120CaO, 40MgO, 30S/ha c t l bnh thp nht, thi k

tr c l 5,6%, thi k chn l 3,7% cho thy kh nng khng bnh cao.


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4.5. nh hng ca bn thm cc cht dinh dng th cp n cc

nng sut ng

Bng 4.6.nh hng ca bn thm cc cht dinh dng th cpn nng sut sinh khi v h s kinh t ca cy ng

CTTNNng sut

ht(kg/ha)

Nng sutph phm

(kg/ha)

Nng sutsinh khi(kg/ha)

H skinh t

1 2510 4705 7215 0,352 4905 8355 13260 0,373 5198 8480 13680 0,384 5250 8565 13815 0,385 5290 8630 13920 0,386 5150 8590 13740 0,387 5165 8500 13665 0,388 5005 8635 13640 0,379 5115 8170 13285 0,3910 5405 8655 14005 0,3911 5510 8740 14250 0,3912 5525 8900 14425 0,38

Kt qu nghin cu bng 4.6 mt ln na cho thy: cc ch bn

phn khc nhau c nh hng r rt n cc nng sut ng.

Cc cng thc c bn phn khong khng ch lm tng nng sut ng

ht m cn lm tng nng sut ph phm (thn, l, li) t 3465 4195 kg/ha,

nng sut sinh khi t 6045 7210 kg/ha so vi i chng khng bn.


vi cng thc bn 135N, 90P2O5, 100K2O/ha (CT 2) thy nng sut ph phm

tng t 125 275 kg/ha, nng sut sinh khi tng t 405 660 kg/ha. iu ny


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chng t rng nh hng ca tng cht dinh dng trung, vi lng n cc nng

sut sinh khi v ph phm ca ng l ng k.


(CT 2, 8) thy CT 8 c nng sut ph phm v nng sut sinh khi cao hn CT 2 l280 kg/ha v 380 kg/ha. Nh vy vi cng mt lng bn nhng cch bn khc

nhau c kh nng nh hng n nng sut sinh khi v nng sut ph phm.



nng sut ph phm v nng sut sinh khi cao hn r so vi CT 2 l 300

kg/ha v 745 kg/ha.

So snh cng thc bn 135N, 90P2O5, 100K2O, 120CaO, 40MgO,30S/ha (CT 10) vi cng thc bn 135N, 90P2O5, 100K2O, 120CaO, 40MgO,

30S, 3,4ZnSO4, 10Borax/ha (CT 12) thy CT 10 c nng sut ph phm v

nng sut sinh khi thp hn CT 12 l 245 kg/ha v 420 kg/ha.

So snh cc cng thc 9, 10, 11 thy nng sut ph phm ca CT 10

cao hn CT 9 l 485 kg/ha nhng thp hn CT 11 l 245 kg/ha. Nng sut

sinh khi ca CT 10 cao hn CT 9 l 720 kg/ha nhng li thp hn CT 11 l

175 kg/ha. Nh vy khi gim lng N, P, K bn th nng sut ph phm,nng sut sinh khi u gim. Ngc li khi tng lng N, P, K bn th nng

sut ph phm v nng sut sinh khi tng.

H s kinh t i vi ng t gi tr t 0,35 0,39. Cng thc khng bn

phn (CT 1) c h s kinh t thp nht 0,35 cn cc cng thc c bn phn c

h s kinh t t t 0,37 0,39. iu ny cho thy cc cng thc c bn phn

u c h s kinh t cao hn so vi cng thc khng bn phn khong (CT 1).


vi cng thc bn 135N, 90P2O5, 100K2O/ha (CT 2) thy CT 2 c h s kinh

t thp nht 0,37 cn cc CT 3, 4, 5, 6, 7 u c h s kinh t l 0,38.


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h s kinh t cao hn nhiu CT 2. Nh vy khi bn y v cn i cc cht

dinh dng khng nhng lm tng nng sut sinh khi m cn lm tng mnhh s kinh t v nng sut ht cho cy ng, s mang li hiu qu kinh t cao.



30S, 3,4ZnSO4, 10Borax/ha (CT 12) thy CT 10 c h s kinh t cao hn CT

12. iu ny cho thy CT 12 bn nhiu hn CT 10 nhng nng sut ht tng

khng nhiu do hiu qu kinh t t c l khng cao.

4.6. nh hng ca bn thm cc cht dinh dng th cp n chtlng ht ng

Bng4.7. nh hng ca bn thm cc cht dinh dng th cpn mt s ch tiu cht lng ht ng

CTTN hm lng proteintrong ht (%)

Nng sut protein(kg/ha)

Hm lng tinh bttrong ht (%)

1 7,38 185,1 25,3

2 7,63 374,0 25,7

3 7,63 396,5 26,0

4 7,63 400,3 26,0

5 7,69 406,7 26,0

6 7,69 395,9 26,0

7 7,69 397,1 26,0

8 7,63 381,6 25,8

9 7,56 386,8 26,0

10 7,75 418,9 26,0

11 7,75 427,0 26,0

12 7,75 428,2 26,0


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Cc ch bn phn khc nhau c nh hng n hm lng protein

trong ht. So snh cc cng thc c bn phn khong vi cng thc khng bn

(CT 1) nhn thy hm lng protein trong ht tng t 0,18 - 0,37%, nng sutprotein tng t 188,9 - 243,1 kg/ha.

So snh cc cng thc c bn b sung thm 30S, 120CaO, 40MgO, 10Borax,

3,4ZnSO4.H2O trn nn 135N, 90P2O5, 100K2O/ha (CT 3, 4, 5, 6, 7) vi cng thc

bn 135N, 90P2O5, 100K2O/ha (CT 2) cho thy bn thm cc cht trn lm hm

lng protein trong ht tng 0,03 0,06, nng sut protein tng t 7,6 26,3 kg/ha.

So snh cng thc bn 135N, 90P2O5, 100K2O/ha (CT 2) vi cng thc bn135N, 90P2O5, 100K2O, 120CaO, 40MgO, 30S/ha (CT 10) thy CT 10 c hm

lng protein trong ht cao hn l 0,12% v nng sut protein cng cao hn 44,9

kg/ha so vi CT 2. iu ny ni ln rng khi bn cc cht dinh dng th cp

cho ng lm tng mnh hm lng protein v nng sut protein trong ht ng.

So snh cng thc bn 135N, 90P2O5, 100K2O, 120CaO, 40MgO, 30S/ha

(CT 10) vi cng thc bn 135N, 90P2O5, 100K2O, 120CaO, 40MgO, 30S,

3,4ZnSO4, 10Borax/ha (CT 12) thy hai cng thc ny c hm lng protein trong

ht l nh nhau nhng nng sut protein ca CT 10 thp hn CT 12 l 9,3 kg/ha.

So snh CT 9, 10, 11 thy khi gim lng m bn (CT 9) th hm

lng protein trong ht gim, thp hn so vi CT 10, 11 l 0,19%. Nng sut

protein ca CT 10 cao hn CT 9 l 32,1 kg/ha v CT 10 thp hn CT 11 l

8,1 kg/ha. Nh vy bn cc cht dinh dng cho ng nhng mc thp

lm hm lng protein v nng sut prtein trong ht gim so vi mc bn CT 10 nhng khi tng lng bn mc cao hn khng lm hm lng

protein trong ht tng. iu ny cho thy cng thc bn 135N, 90P2O5,

100K2O, 120CaO, 40MgO, 30S/ha (CT 10) cho cht lng sn phm tt.


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Cc ch bn phn khc nhau c nh hng n hm lng tinh bt

trong ht ng. So snh cc cng thc c bn phn khong vi cng thc khng

bn (CT 1) thy hm lng tinh bt trong ht tng t 0,4 - 0,7%.

Cc cng thc c bn phn u c xu hng lm tng hm lng tinh

bt trong ht ng.

4.7. nh hng ca bn thm cc cht dinh dng th cp n hiu

lc v hiu sut ca phn bn cho ng

4.7.1.nh hng ca cc ch bn phn n hiu lc phn bn cho ng

Bng 4.8. nh hng ca cc ch bn phnn hiu qu s dng phn bn cho ng

Bi thu nng sut so vikhng bn phn

Bi thu nng sut so vich bn N,P,K

CTTNNng sut ht

(tn/ha)Kg/ha % Kg/ha %

1 25102 4905 2395 95,43 5198 2688 107,1 293 6,04 5250 2740 109,2 345 7,0

5 5290 2780 110,2 385 7,86 5150 2640 105,2 245 5,07 5165 2655 105,8 260 5,38 5005 2495 99,4 100 2,09 5115 2605 103,8 210 4,3

10 5405 2895 115,3 500 10,211 5510 3000 119,5 605 12,312 5525 3015 120,1 620 12,6


Cc ch bn phn khc nhau c nh hng n hiu qu s dng phn

bn cho ng. So snh cc cng thc c bn phn khong vi cng thc khng

bn (CT 1) cho thy hiu lc rt cao ca phn khong bn cho ng trn t bc

mu, lm tng nng sut ng t 2395 3015 kg/ha (tng 95,4 120,1%).


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Cc cng thc c bn b sung thm 30S, 120CaO, 40MgO, 10Borax,

3,4ZnSO4.H2O trn nn 135N, 90P2O5, 100K2O/ha (CT 3, 4, 5, 6, 7) lm tng

nng sut ng t 245 - 385 kg/ha (tng 5 - 7,8%) so vi bn 135N, 90P2O5,

100K2O/ha (CT 2). Nh vy cc cng thc c b sung thm cc cht dinhdng (CT 3, 4, 5, 6, 7) lm tng c hiu qu s dng phn N,P,K kh r.

Cc cng thc 9, 10, 11, 12 lm tng nng sut t 110 - 520 kg/ha (tng

2,3 - 10,6%) so vi CT 2 , cho thy c bn v cn i cc cht dinh dng cho

hiu qu s dng phn bn cao hn c. Trong

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