KHOA HOC CONG NGHl
T I I V H TQAIM LUDIXIG DAIVI BOIM V A O T H O I K Y T R U O C T R O 1 0 IMEiAY D U A V A O C H i S O D I E P LLJC CHO M O T
S O GIOIXIG IXIGO V U DOIVG T A I T H A I IVGUYEIXI Biii van Quang^, Nguy&i Thd Hiing=, Nguy&i Thi Lln^, Tiln Thmg Kidn^ Ph?m Qudc Toatf
T6MTAT
Thi nghi&ra nghifin cdu xac dinh luong dam boo cho ng6 tiioi k^r tnroc tr5 10 ngay dua vao chi sd difip luc (CSDL) ovu dong tai Thai Nguyfin dupc ten hanh Iren hai gidng ng6 lai LVN99, LVN14. Thi nghifim gom 17 cong thiic voi luong dam (N) bon khac nhau qua cac thoi ky sinh tnrdng d a ngo. Kdt qua thi nghiem hai nam 2011 va 2012 cho thiy: O giai doan truoc trd 10 ngay h& so sii dung dam (SDD) phu thugc ca vao luong bon thai ky 8-9 la va luong bon then ky truoc trd 10 ngay. Nhom cong thiic khong bon N a thoi ky 8-9 la co hifiu suat SDD cao nhat (12,1 - 18,3 kg ngo/kg N), nhung nhom cong thiic b6n 75 kg N/ha d ttioi ky 8-9 la CO hifiu suat SDD nho nhit CSDL it thoi ky truoc trd 10 ngay co tuong quan chat voi nang suit Lupng d^m bon, CSDL va nang suit ng6 co quan hfi theo phuong trinh Y = - 288,1007 + 17,52617 * CSDL + 1,144589 * Nao,2218583*CSDU-0,001945353*N3^-O,02703836*CSDL*N voi R^=0,92. Dua vao phuong trinh nay ta co thd tinh toan duoc luong dam bon cho ngo giai doan truoc tro 10 ngay khi bidt gii tn CSDL (do nhanh tren dong ruong) de dat nang suat muc tieu.
Ti^Ui6a: Chl sd diep luc, dam, ngd. Thai NguySn, tiidi ky trade trd 10 ngay, vgdong.
1 . BAT VAN B^
Cay ngd (Zea mays L) la mdt trong ba c^y quan trpng cung d p luong thiic cho loai ngudi, la ngudn thuc an cho gia siic, cung d p nguydn lidu cho cdng nghidp, lim hang hda xuat khau (Ngd Hiiu Tinh, 2003) [4]. O Viet Nam, ngd i l cay luong thuc thu hai sau d y liia, mac du nhiing ndm gan day, sin xuat ngd da dat duoc nhimg thinh tuu ldn nhd phit tiien gidng ngd lai vl cii thidn cic bidn phip ky thuat canh tac nhung nang suat binh quan cdn thap, gia thinh san xuat cao. Nang suit ngd binh quSn ciia nudc ta nam 2013 dat 44,3 ta/ha, bing 80,25% nang suat ngd binh quan cua thd gidi, bing 44,43% nang suit ngo bmh qudn cua My (FAO, 2015) [7].
Dd nang cao nang suat va san luong ngd can tie ddng rlt nhidu d c bidn phap ky thu^t, trong do phan bdn cd vai trd rlt quan trong, anh hudng tdi 30,7%
ndng suit (Berzeni, Gyorff, 1996) [5]. Trong sd d c nguyen td da lugmg thiet ydu thi dam dupc xem 11 nguyen td quan trpng nhat cho qui trinh sinh tnrong than la, nd hoa vl hinh thinh hat. Hidn nay, dam thudng dupc bdn vdi lieu lupng vl thdi gian dinh tnrdc trong khi nhidu nha khoa hoc da chiing minh ring, nhu d u ve dam ciia cay trdng bidn ddi rat ldn
' Ph6ng Kinh tfi Thanh pho Cim Pha - Quang Ninh
^ Trudng Dai hpc Nong LSm Thiii Nguyen
do su khac nhau ve kha nang cung d p dam ciia dat va tinh trang dinh duong N cua cdy. Vi vay, bdn dam theo sd lirong va sd lan dinh sin nhu qui trinh khuyen cao khdng tranh khdi khi thua, khi thieu dpm (Dobermann vl cs, 2003) [6]. Bi tang ndng suit va hidu qua sir dung dam thi lidu lupng va thdi gian bdn d^m can dupc xac dinh de du doan nang suit, ddng thdi xac dinh lupng dam cln bdn cho ngd d thdi ky sinh truong sinh duong.
Nhidu nghien cuu ve quan ly dinh duong dam cho ket qui: Su khac nhau ve chi sd dipn tich 11, khdi lupng chat khd, him lupng didp luc vl him lupng dam trong 11 ddu lim cho phan xa va hap thu Inh sing ciia 11 khic nhau (Thomas va cs, 1995; Uhart, Andrade, 1995) [8], [9]. May do chi so didn tich la (CSDL) (SPAD-502, Minolta, Ramsey, NJ) 11 chi sd tin c$y phan Inh h i m lupng diep luc trong 11 va cd tuong quan ch$t vdi ham lupng N trong than la. Tren the gidi, nhieu tic gia da sii dung may do CSDL de xlc dinh him lupng diep luc trong la cay, tinh trang dam cua d y , du tinh lidu lupng v l thdi gian bdn N, du tinh nang suit cdy trdng. Tuy nhidn, nhitag nghidn cuu niy d Vidt Nam chua cd nhieu, ddc biet chua cd nghien ciiu nio dupc thuc hien d Viet Nam ve su dung CSDL trong tinh toin lupng dam bdn cho ngd thdi ky trudc trd 10 ngay.
Xuat phit tir van dd trdn chung tdi da tidn hanh nghien ciiu de tii: 'Xic dinh luong dam bon cho ngd NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 11/2015 25
KHOA HOC CONG NGHE
vao thoi ky iruoc tid 10 ngay dua vao chi so diep Iuc".
2 . VAT I E U VA PHUDNG PHAP I W H e i Cini 2.1. Vat lieu nghifin oiu
Gdm 2 gidng ngo lai LVN14 (Gl) va LVN99 (G2) do Vien Nghien cihi Ngo chon tao.
2.2. Dia didm va thdi gian nghien ciiu Dia diem nghien cuu: Thi nghiem dupc tien hanh tai Khu Thi nghiem cay trdng can - Trudng Dai hpc Nong Lam - Dai hoc Thai Nguyen.
Thdi gian nghien ciiu: Thi nghiem dupc tidn hanh dvu dong 2011 vavu dong 2012.
2.3. Phuong phap nghidn ciiu
Thi nghiem phan bon dupc bd tri theo kieu 6 chinh 6 phu (Split-Plot Design). 3 lln nhic lai, d ldn la hai gidng ngo lai LVN14 va L\'N99 va 6 nhd la 17
Bang 1. Cac cdng thiic bdn dam trong thi nghidm
cong thuc (cd 1 cdng thuc khong bdn dam, 16 cong thiic bdn d thdi ky va lupng bdn khac nhau). Dien tich cac 6 nhd la la 35 m- (7 m x 5 m), dien tich 6 lon la 68,6 m-. Gieo trdng 7 hang/d vdi khoang each 70 cm X 25 cm (mat do 57.000 cay/ha). Mdi cong thiE phan bon thi nghiem duoc tien hanh tren 2 gidng ngo lai LVN14 va LVN99. Ndn thi nghiem: 2 tin phan huu CO VI sinh + 90 P.Os + 90 K.O. Cac chi tieu theo doi va phuong phap theo doi dupc tien hanh theo Quy chuan ky thuat qudc gia ve khao nghiem gia tn canh tac va sii dung ciia gidng ngo (QCVN 01-56:
2011/BNNPTNT). Chi sd diep luc dupc do bdng may (may SPAD 512 Minota) do vao nhirng liic troi khong mua, trudc bdn phan mpt ngay, thdi ky trubc trd 10 ngay (xoay non); do la dau tien tii tren xuong (do 3 diem each nhau 3-5 cm va tinh trung bmh ciia 3 lan do) do d khoang giiia la tinh tii be den miit la va do d phan giiia tinh tu mep la den phin gdn la d giiia CT
1 2 3 4 5 6 7 8 9
Lining N bon vao thoi ky (kg N/ha) 4-5 la
0 50 50 50 50 50 50 50
8-914 0 0 0 0 0 25 25 25
TnlDc trd 10 ngiy
0 0 25 50 75 0 25 50 50 1 25 75
CT
10 11 12 13 14 15 16 17
Luong N b6n v4o thcri ky (kg N/ha) 4-5 la
50 50 50 50 50 50 50 50
8-9 la 50 50 50 50 75 75 75 75
Tnroc tro 10 ngSy
0 25 50 75 0 25 50 75
3. KFT QUA VA THAO LUAN Hieu qua SDD (su dung dam) ciia mdt sd giong
ngd lai vu dong dupc tinh thong qua 2 thong sd: He sd SDD (phan tram Iupng dam hap ihu so voi luong dam bon) va hieu suat SDD (kg ngo hat/kg N). Ket qua tinh toan duoc the hien qua bang 2 va 3.
Bing 2. Hd sd sii dung dam d rapt sd thdi ky sinh trudng ciia mdt sd gidng ngd lai thi nghidm vu ddng
^ 1 1 vl 2012) (sdhcu U-ung bmh 2 vu) 3.1. Hidu qua sir dung dam d okc thdi ky sinh
trudng cua mdt sd gidng ngo lai thi nghidm vu dong ndm 2011 vd 2012
CAng fluic diumgN
Ixte) KOAO) 2(50ftO) 3(50*25) 4(50*50) 5(50*75) 6(50-^:0)
Lirpng N cay hiit (kg/ha) Gl ' G2
He so sii dung dam bon a thoi ky... (90 Chung cho cavu
Gl G2
41,3 1 43,2 ! - ! 60,2 61.6 73,6 75.1 89,0 91.0 105,8
76.7 106,3
77,6 37,9 43.1 47,7 51,6 47,2
36,7 42,5 47,8 50,5 45,8
8 - 9 1 4 Gl
65,8 G2
Trade trf 10 ngiy Gl
53,4 57,5 60.7 63,9
G2
54,2 58,9 59,7
N O N G NGHIEP VA PHAT TRIEN N O N G THON - KY I - THANG 11/2015
KHOA HOC CdNG NGHE 7(50-25:25)
8 (50-25:50) 9 (50-25:75) 10 (50:50:0) 11 (50:50-25) 12 (50:50:50) 13 (50:50:75) 14 (50:75K)) 15 (50:7525) 16 (50:75:50) 17 (50:75:75)
92,1 106,6 119,1 88,5 105,0 118,7 127,5 97,9 112,9 126,4 132,1
92,4 106,4 119,3 88.7 104,7 119,9 128,5 99,4 113,5 125,9 130,6
50,8 52.3 51,9 472 51,0 51,6 49,3 45,3 47,8 48,6 45,4
492 50,6
50,7
.
45.4 1 56,4 492 ' 51,1 48,7 ' 44,9 46,8 47,3
50,3
43,7
_
54,2
_ .
50,4 61,7 59,9 56,6 66.4 60,5 52,0
-
60,1 56,9 45,6
59,5 57,8 55,6
.
64,2 62,4 53,1
.
56,3 53,1 41,7 Ket qua 6 bang 2 cho thay:
He sd SDD bdn 6 thdi ky 4 -5 11 cua ngd khong cao, trung binh 2 vu dat 37,9% (gidng LVN14) va 36,7% (gidng LVN99).
He sd SDD bdn 6 thdi ky 8- 9 la cd xu hudng ^ le nghich vdi lupng dam bdn. Cdng thiic bdn 25 kg N/ha c6 he sd SDD cao nhat 1165.8% (gidng LVN14), 63,9% (gidng LVN99). Cdng thiic bdn 75 kg N/ha cd he sd SDD thap nhat la 50,3% (gidng LVN14), 50,4%
feidngLVN99).
Hd so SDD 6 thoi ky trudc trd 10 ngay phu thude vao d lugng dam bdn d ftidi ky 8-9 la va bdn trudc fid 10 ngay. Nhdm cdng thiic khdng bdn dam d tiidi ky &-9 la cd hd sd SDD cd xu hudng tang theo lupng dam bdn othdi ky trudc trd 10 ngay, dat 53,4 - 60,7%
aVN14), 54,2 - 59.7% (LVN99). Cic nhdm cdng tinic khic cd he sd SDD ty Id nghich vdi lupng dam bdn, cdng thuc bdn 25 kg N/ha vao thdi ky trudc trd 10 ngay cd hd so SDD cao nhat, cdng thuc bdn 75 kg N/ha cd hd sd SDD thap nhaL
32. H i ^ SU& sii dung dam
Hieu suit sii dung dam dugc thd hidn d bing 3.
Sd lieu 6 bing 3 cho thiy hieu suit su dung dam 6
thin ky 4 - 5 la k h i cao, dat 23,4 kg ngd hat/kg N aVN14), 23,1 kg ngd hat/kg N (LVN99).
Hidu suit sii dung dam a thdi ky 8-911 tang ty le n ^ c h vdi lupng dam bdn. Cdng thiic bdn 25 kg N/ha cd hidu suat SDD cao nhat 24,6 kg ngd hat/kg N (LVN14), 24,8 kg ngd hat/kg N (LVN99). Cdng thiic bdn 75 kg N/ha cd hipu suit SDD thap nhat 11 14,9 kg ngd hat/kg N (LVN14), 15,5 kg ngo hgt/kg N (LVN99).
Hieu suit sii dung dam d thdi ky trudc trd 10 ngay phu Ihudc vio d lupng dam bdn d tiidi k^ S-911 va thdi ky trudc trd 10 ngiy. Nhdm cdng thiic khdng duoc bdn dam d tiidi k^ &-911 (CT 2, 3, 4, 5) cd hieu suit SDD la 12,1 - 18,3 kg ngd hat/kg N a V N U ) , 12.6 - 20,6 kg ngd hat/kg N (LVN99).
Nhdm cdng tinic dupc bdn 25 kg N/ha vao thdi ky 8-9 la (CT 6, 7, 8, 9) cd hieu suat su dung dam dat 10,3 - 17,6 kg ngo hat/kg N (LVN14), 10,5 - 17,1 kg ngd hat/kg N(LVN99).
Nhdm cdng thiic dupc bdn 50 kg N A a vio thdi ky &-9 11 (CT 10,11,12,13) cd higu suit SDD gilm rat nhieu so vdi miic bdn 25 kg N/ha, chi dat 4,5 - 13,0 kg ngo hat/kg N (LVN14), 4,3 - 13,4 kg ngd hat/kg N(LVN99).
Bang 3. Hidu suit su dung d^m d mdt sd thdi 1^ sinh tiudng ciia mdt sd gidng ngd lai thi n g h i ^ vu ddng (2011 v l 2012) (sd heu trung bmh 2 vu)
Cdng fliiic (Lugng Nb6n) 1(0*0) 2(50*0) 3(50*25) , 4 00*50)
; 5(50*75)
Ndng suat ( t ? / h ^ Gl 33,43 45,13 49,72 52,85 5420
G2 34,12 45,65 50,79 53.48 55.07
Hi^usuat Chun^ cho cavu
Gl 23,4 21,7 19.4 16,6
G2 23,1 222 19,4 16,8
su dung dam bdn or thdi k^...
(kg hat/kg N)
8-914 TrmictrolOngay Gl G2 Gl
18,3 15.4 12.1
G2
20.6 15,7 12,6
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 11/2015
KHOA HOC CdNG MGHJ
=.!
6 (50:25:0) 7 (50:25:25) 8 (5025:50) 9 (50:25:75) 10 (50:50:0) 11 (50:5025) 12 (50:50:50) 13 (50:50:75) 14 (50:75:0) 15 (50:75:25) 16 (50:75:50) 17 (50:75:75)
51,27 55,68 57.24 58,99 54,77 58,02 59,65 58,14 56,33 59,35 58,62 53,63
51,85 56,12 57,79 59,71 55,81 59,15 60,48 59,04 5727 60,42 58,85 53,90
23,8 22,3 19,1 17,0 21,3 19,7 17,5 14,1 18,3 17,3 14,4 10,1
23,6 22,0 18,9 17,1 21,7 20,0 17,6 142 18,5 17,5 14,1 9,9
24,6
19,3
14,9
24,8
-
17,6 11,9 - 1 10,3 20,3
15,5 13,0
9,8 4,5 12,1 4,6 -3,6
^ 17,1 11,9 10,5 _ 13,4
9,3 4,3 12,6 32 -4,5 Nhdm cdng thiic dupc bdn 75 kg N/ha vio tiidi
ky 8-9 la (CT 14,15,16,17) cd hieu suit SDD gilm rO ring theo lupng dam bdn a tiidi ky trudc trd 10 ngiy. Cong thiic bdn 25 kg N/ha cd hieu suit SDD dgt 12,1 kg ngd hat/kg N (LVN14), 12,6 kg ngd hat/kg N (LVN99); cdng tinic bdn 75 kg N/ha cd hidu suit SDD giam manh va chi dat 3,6 kg ngd hat/kgN (LVN14),4,5kgngdhat/kgN (LVN99).
3.3. Anh hudng cua d c cdng thiic bdn dgm ddn him lupng d^m trong d ^ , chi sd d i ^ l^c tiidi ^ trudc trd 10 ngiy v l ndng suit ngd
Theo nghidn ciiu cua nhidu tic gil thi CSDL vl
trudc trd 10 ngiy tuong quan chat vdi nang suat aia cay trdng (Nguydn Thi Hieu, 2012; Nguydn Thi Lan vacs., 2008; Phgm Qudc Toin. 2012)[2], [3], [4].M qui thi nghiem cho thiy lupng dam bdn va CSDL co tuong quan, anh hudng tdi hd sd SDD, hidu suat SDD, nang suit cua 2 gidng ngd lai.
Chling tdi tidn hinh lay mSu trudc khi bdn phan 1 ngay vio giai doan trudc trd 10 ngay dd xac dinh him lupng dam (HID) trong tiian, CSDL HLD, CSDL vl nang suit la ket qui tnmg binh cua 2 giong vl 2 vu dong nam 2011 vl 2012 dupc trinh bay tai bang 4.
him lupng dam (HID) b-ong than giai dogn 8-9 la vl
Bing 4. Him lupng d^m, chi sd didp Ivc tiidi I ^ trudc tr6 10 ngiy v l ndng suit ngd trung binh vy ddng (2011 v l 2012)
CT 1 2 3 4 5 6 7 8 9
CSDL 28,930 32,818 32,280 32,362 32,200 33,650 33,717 34,270 33,600
HLBeO 1,14 1,31 1,32 1,29 1,33 1,52 1,55 1,54 1,52
NS (t?l/ha)
33,77 45,39 50,25 53,16 54,64 51,56 55,90 57,51 59,35
CT 10 11 12 13 14 15 16 17
CSDL 35,593 35,333 35,710 35,370 37,570 37,748 37,870 37,535
HLD (90 1,74 1,73 1,75 1,76 1,91 1,94 1,93 1,93
NS (ts/ha) 55,29 58,58 60,06 58,59 56,80 59,89 58,73 53,76 D^ thay duoc moi quan h^ giua CSDL vi nang suat tien hanh phan tich h6i quy va k^t qua dupc trinh bay a phuong trinh (1) va do thi 1.
NS . - 0,4152 CSDL' + 30,208 CSDL - 491,17 R ' - 0 , 7 5 (PTl)
Phuang trinh (1) va do thi 1 cho tiiay quan h^ giua CSDL thoi ky truoc tr5 10 ngay va nang su^ ngo vii dSng (2011 v4 2012) la phuong trinh bac 2 vdi h i s6 IP- 0,75. Nhu vay co M sir dung CSDL la mdt trong nhing chi tidu de dtr bdo nang suat ngd cd do tin cay cao. MSt NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 11/2015 tang ty le thuan vdi luong dam bdn; HUD trong cay va
CSDL d cdng thiic 1 do khdng bdn ndn ihip hon nhdm cic cdng thiic khac lan luot theo thii tu tang dan la:
Nhdm cdng thiic 2, 3, 4, 5, nhdm cdng thiic 6, 7, 8, 9, nhdm cdng thiic 10, 11,12,13 va nhdm cdng thiic 14, 15,16,17.
Nang suat ngd d cdng thuc 1 do khdng bdn dam d c4c thdi kJ ndn cd nang suit thip nhSt.
28
KHOA HOC CONG NGHE
khac, vide xac dinh CSDL cd thi thuc hidn nhanh va chi phi fliap hon so vdi phuong phap xac dinh H I S trong cay.
V v D « n g
3.4. l i n h t o i n lugrng d^m bon cho ngd dua v i o chi sd didp luc
Qua ket qui tren chpn chi tieu CSDL de xay dung qui trinh tinh toin lieu lupng N bdn thiic cho ngd giai dogn trudc trd 10 ngiy. Kdt qua phin tich hdi qui da bidn de xac dinh Inh hudng dia CSDL trudc khi bdn vl Ueu lupng dam bdn thdi ky trudc trd 10 ngiy (N3) tdi nang suat ngd dupc the hien d phuong trinh (2):
Dd thi 1- Quan hd giQa CSDL va nang suit ngd vy ddng (2011 v l 2012)
Y = - 288,1007-Hl7,52617*CSDL+l,144589*N3-0,2218583*CSDL2-0,001945353*N32-O,02703836*CSDL*N R^=0,92 (PT2)
Cic thdng sd cua phuang trinh: R^=0,92; sai sd trung binh: 1,77 (ta/ha) hxong duong vdi 3,26%.
Trong do: Y: Nang suat hat ciia ngo d vu ddng (tg/ha). CSDL: Chi sd didp luc do d thdi 1^ budc trd 10 ngay. N3: Lupng dam bdn d thdi k^ trudc trd 10 ngay Otg/ha).
Nang suit ngd vu ddng tuong quan dudng cong b£kc 2 vdi ca CSDL vl lupng dam bdn vio thdi ky trudc trd; dd dat nang suat cao nhat thi CSDL vl lupng dam bdn vao thdi ky trudc trd 10 ngiy trong thi nghidm tuong iing khi giai phuong trinh (2) 11: 37 v l 37 kg N/ha, khi dd nang suit dat 59,31 ta/ha.
Didu niy cd nghia 11 ndu CSDL vl luong dam bdn vao thdi ky trudc trd 10 ngiy ldn hon tri sd tren thi nang suit ngd se giam, nang suat dat dupc cao nhat dd gpi 11 nang suit tdi da vd ky thuat (Nguydn The Dang v i e s . , 2011) [1].
Bing 5. Khuydn d o higng dam bdn cho ngd drtiidi 1^ trudc trd 10 ngiy theo CSDL Phuong trinh (2) cd he sd R^ dat 0,92 cd nghia 11 trong didu kien tiii nghiem, bidn dpng cua CSDL vl lupng dgm bdn giai doan trudc trd 10 ngiy quyet dinh tdi 92% gil tri bidn ddng cua nang suit ngd vu ddng. Sai sd trung binh giiia nang suit du blo theo phuong trinh (2) vdi nang suat thuc te 111,77 ta/ha v l sai sd giiia nang suit du bao va nang suat thuc te 113,26%.
3.5. Fhuong p h ^ tra bang dd xlc dinh lupng N bdn tdi da vd k^ thuSt v l Iupng dgm bdn tdi tiiich v^
kinhtd
De giup cho cln bd khuydn ndng v l ndng dan cd the dd ding bidt dupc lupng N cln bdn nhim dat dupc nang suit tdi da ve ky thuat v l nang suit tdi thich ve kinh te khi hp bidt CSDL trudc khi bdn (do bing miy do CSDL), chiing tdi tinh toan dua vao phuong trinh (2). Kdt qua dupc trinh bay d bing 5.
Thdi vu
1 Vu ddng
Chi so diep luc
2 29 30 31 32 33 34 35
Nang suat khdng bdn dam (ta/ha)
3 33.58 38,01 42.00 45.55 48,66 51.32 53,54
Luong dam can bdn va hieu suat sii dung dam ling vol cac miic nang suit N bdn tdi thich ve kinh te
Nang suat (ta/ha)
4 49,96 52,08 53,92 55,31 56,65 57.72 58,36
Luong dam can bdn (kg/ha) 5 80 75 70 60 55 50 40
Hieu suat ciia dam (kg ngd
/kgN) 6 20,5 18,8 17,0 16,3 14.5 12.8 12.0
N bdn toi da ve ky thuat Nang suat
(ta/ha) 7 50,27 52,29 54,07 55,58 56,84 57,84 58,59
Luong dam cin bdn (kg/ha) 8 93 84 79 70 65 57 50
Hidu suat cua dam (kg ngd /kgN)
9 17,9 17,0 153 14,3 12,6 11,4 10,1
jlJNONG NGHIEP VA PHAT TRIIN NONG THON - KY 1 - THANG 11/2015 29
KHOA HOC CdNO NOHE
5531 57.53 57,97
58,70 58,85 58,68 10
113 9,5 7,1
59,08 59,31 59,02
30 7,2 5,9
Cach tra bang: Trong bang 5 d thdi ky trudc trd 10 ngay, CSDL cua ngd duoc bd lii d cdt 2, nang suit khdng bdn dam d cdt 3... va hidu suat cua dam d cdt 9. Vi du khi do CSDL cua ngd d giai doan trudc trd 10 ngiy dupc chi sd 36 (cdt 2) thi luong N d n bdn de dat nang suit tdi da vd ky thuat la 44 kg N/ha (cdt 8) vi nang suit cd th^ dat theo tinh toan la 59,08 ta/ha (cdt 7) vdi hidu suit SDD la 8,6 kg ngd/kg N (cot 9).
Tuong iing khi tra luong N bdn tdi thich ve kinh te la 30 kg N/ha (cdt 5) thi nang suit cd the dat theo tinh toin 14 58,70 ta/ha (tra cdt 4) va hieu suit su dimg dam la 11,3 kg ngd hat/kg N bdn (cdt 6).
Bing 6. Nang suit va cic roiic dam khi bift CSDL
Tidp tuc tra bang, vdi m6i CSDL ta cd thl tinh toan dupc luong dam can bdn de dat nang suit tdi da ve ky thuat hoac tdi thich vd kinh td.
3.6. Bing tra Ding suit kfai bift chi sd di$p life vi lupng N bdn
Tir khoang gia tri CSDL Ihuc t^ trong thi nghifm (td 29 ddn 39) va lupng N bdn thtrc ti thdi ky time trd 10 ngay (0-75 kg N/ha) khi tiin hanh thi nghiftn vu ddng (2011 va 2012). chling tdi lap bang tra nSng suit khi cd gia tri CSDL (theo cdt) va luong N bon thuc thdi ky tmde trd 10 ngay (theo hang). Kit qua dupc trinh bay d bing 6.
Nbdn r.SDI, (1) 29 30 31 32 33 .34 35 36 37 38 39
0 (2) 33.58 38,01 42,00 45,55 48,66 51,32 53,54 55,31 56,64 57,53 57,97
10 (3) 36,99 41,15 44,87 48,15 50,99 53,38 55,33 56,83 57,89 58,51 58,68
Nang suit (ts>/ha) 20
(4) 40,01 43,90 47,35 50,36 52,93 55,05 56,73 57,96 58,75 59,09 59,00
30 (5) 42,64 46,26 49,45 52,18 54,48 56,33 57,74 58,70 59,22 59,29 58,93
dat dupc d cic rmic d^m 40
(6) 44,88 48,24 51,15 53,62 55,64 57,22 58,36 59,05 59,30 59,10 58,46
50 (7) 46,74 49,82 52,46 54,66 56,41 57,72 58,59 59,01 58,99 58,52 57,61
(kg/h^
60 (8) 48,20 51,01 53,39 55,31 56,80 57,83 58,43 58,58 58,29 57,55 56,38
70 (9) 49,28 51,82 53,92 55,58 56,79 57,56 57,88 57,77 57,20 56,20 54,75
75 (10) 49,67 52,08 M,04 55,56 56,64 57,27 57,46 57,2:
56,51 55,37 53,79 Bing 6 cho thiy, cu mdi gil tri cua CSDL khi
bdn cic miic dgm khic nhau thi thu dupc nang suit tuong ling khi tra bing. Vi du: Cd CSDL 1136 (cdt 1) khi khdng bdn dam (cdt 2) thi nang suit du blo se 11 55,31 tg/ha; ndu bdn 50 kg N/ha (cot 7) tiii nang suit se 11 59,01 tgAa. Hoac khi bidt CSDL, mudn dupc nang suit muc ti^u dinh trudc nao dd ta cd thd tra. cic miic dgm tuong iing. Vi du: Khi ta cd CSDL 11 36 (cdt 1), ndu can nang suit dat 50-55 tg/ha; ha bang 5 (cdt 2) dd dgt miic nang suit 50-55 tg/ha thi khdng d n phli bdn; dd dat nang suit 56-58 tg/ha thi tra bing (cdt 3,4) cd cic miic bdn la 10-20 kg N/ha.
4.K^UlANVAfl£NGHi 4.LK^hi|n
- Hd sd SDD va hd suat sii dung dgm bdn o thoi ky trudc hd 10 ngiy phu tiiupc ca vio lupng dgm bon thdi ky 8-9 11 vl lupng dam bdn thdi ky trudc tr6 10 ngay.
- CSDL tiidi ky trudc trd 10 ngiy tuong quan chat vdi nang suit (R^ = 0,75) vl cd thd 11 chi sd tin cay dd du blo nang suit va tinh toan lugng N bon thiic cho ngd d thdi ky trudc trd 10 ngiy dd dat nang suit muc tigu.
4 ^ . D d n g h i
Tiep tuc nghign ciiu trdn nhidu gidng ngd khac v l nhidu dia phuong khac dd cd kdt qui tin c^
khuydn cao sii dung phuong phap bdn dam cho ng*
30 NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 11/2015
KHOA HOC CdNG NGHl dua vao tinh trang dinh duong dam cua cay thdng
qua CSDL TNLranUMKHU
L Nguydn The Dang. Nguy&i Ngpc Nwig, Dang Van Minh, Nguyfa Thd Hung, Duong Thi Thanh Ha, Phan Thi Thu Hing, HI Xuin Linh (2011). Giio tiinh:
Dat va dinh dudng cay trdng. tfeh Nong n ^ e p , HI Nffl.Tr.l75-18L
2. Nguydn Thi Hidu (2012). Nghiin cuu inh huongcuamatdd vahwngdambdn athdiky7-9la dSn sinh truong, phit trien aia mdt sd gidng ngd lai tai Thii Nguyin. Luan van thac si khoa hpc cay trdng. Dai hpc Thai Nguyen.
3. Nguyen Thi Lan va cs. (2008). Sii dung may do CSDL de xlc dinh lupng dgm bdn cho lua vu xuan vio thdi ky lam ddng tai Thai Nguyen. Tap chi Ndng nghiep va Phat trien ndng tiidn. Sd 6. Tr. 17 - 21.
3. Phgm Qudc Toan (2012). Nghiin cuu tieu luang dam bon demy dung cdng thiic bdn phan bop ly thdng qua chi sd diip luc cho ngo vu xuan tai Thai Nguyin. Luan van thac si khoa hpc cay trdng. Dai hpc Thai Nguyen.
4. Ngd Hiiu Tmh (2003). GUo tiinh: Cay ngd.
Nxb Nghe An.
5. Berzenyi, Z., Gyorff, B. (1996). Anh hudng cua cac yeu td trdng trpt khac nhau den nang suit ngd.
Bio Ndng nghiip vi Cdng nghi thuc pham, 7(199).
Tr.5.
6. Dobennann A., Witt C , Abdulrachraan S., Gines H. C , Nagarajan R., Son T. T., Tan P. S., Wang G. H., Chien N. V., Thoa V. T. KL, Phung C. V., Stalin P., Muthukrishnan P., Ravi V., Babu M., Simbahan G. C , and Adviento M. A. A (2003). Soil fertihty and indigenous nutrient supply in irrigated rice domains of Asia, Agron. J 95, pp. 913-923.
7. FAO statistic, 2015.
8. Thomas R., Sinclair, Russell, C. Muchow (1995). Effect on nitrogen supply on maize yield: I Modeling Physiological Responses. Agronomy Journal Vol 87, (4). pp, 632 - 641.
9. Uhart S. A., Andrade. F. H. (1995). Nitix)gen deficiency in maize: 1. Effects on crop growth, development, dry matter, partitionaing and kernel Set Crop science 35 (5), pp, 1376 -1383.
CALCULATION OF THE NTHIOGEN DOSAGES AT 10 DAYS BEFORE FLOWERING BASED ON CHLOROPHYLL INDEX TO SOME CORN VARITIES IN WINTER SEASON
IN THAI NGUYEN
Bui Van Quang^, Nguyen The a n ^ , NguyenTHLatf, TianlhingKieff', PhamQuocToarf 'Cam Pha City Economic Department-Quang Ninh
*Ihai nguyai Univera^ of Agriculture and Forestiy Summary
An expenment including two com vaneties 0^VN99 and LVN14) and 17 trearaents with different N rates and timings was conducted in winter crops of 2011 and 2012 to develop a method for prescrizing N rate applied at 10-day l>efore heading of com UKUg chloropyl meter index (SPAD). The results from the experiment ^ows that ai^lied agronomic N use efficiency is dependent on N rate appLed at both 8 or 9-leaf stage and 10-day before heading. Treatments without N application at 8 or 9-leaf stage have the highest agronomic N use efBdency ranging from 12.1 to 18.3 kg com seed per kg N applied w4iile the Ueatments with 75 kg N applied at 8 or 94eaf stage have the lowest agronomic N use efficiency. Value of SPAD measured at 10-day before heading has high correlation with crop yield. Com yield was predicted by SPAD value and N rare aRjlied at lOday before heading precisely and accurately by equation: Y = - 288.1O07-Hl7.52617*CSDLfl.l44589*N3^.2218583*CSDL^-O.001945353*N3^-O.02703836*CSDL*N wltii R-=0.92. Using tills equation, we may determine N rate when knowing SPAD at lOday before heading to obtain target yield.
Keywords: The clilorophyU, mtrogen, com. Thai Nguyen, before dowering penod of 10 days, winter season.
Ngudi phan bifin: TS. Bui Huy Hife Ngiy n h ^ bli: 25/9/2015 Ngiy thdng qua phan bifin: 27/10/2015 N g ^ d u y ^ dang: 3/11/2015
NONG NGHIEP VA PHATTIitEN NONG THON - KY 1 - THANG 11/2015
