KHOA Hpc CdNG N G H |
I\IGHIEI\I CLTL) Al\IH HU01VG ClIlA C H £ DO CAO D£I\I IXlAlXIG S U A T V A TIIVH TRAIXIG SIIXIH LY IVIIJ TREIXI HAI DblMG V d TilVH RRIV 3 VA P B 2 6 0 TAI D A T X A I U
lVll£l\l DOIVG [\IAIVI BO
Kim Tht ThiiyS D6 Kim Thdnh', Nguyen Thj Thanh Thfe*
T6MTAT
Nghidn ciiu n h i m xac dinh ch^ dO c^o mu thich h(?p cho 2 ddng v6 tinh cao su RRIV 3 vd PB 260 da dut^c tien hanh tir nam 2008 - 2010 tai CT TNHH MTV CS Ddu Ti^ng. Thi nghidm bao g6m 8 ch^ d$ c^o mi^ng ngua S/2 v6i nhip dO ego d3 ho|ic d4 k^t hpp kich thich 4, 6 , 8 lAn/nim vjk ddi chiing khflng kich thich. K^t qua cho th^y cdc ch^ dfl cao k^t hgp v6i kich thich d^u cho nSng su^t cao hon so v6i nghidm thurc ddi chung kh6ng kich thich tr&n ca hai nhjp dO ego d3 vi d4. Giira hai nhjp dfl c^o thi ch^ dO c?o nhjp dfl d4 cho nSng su^t ca t h i gam trdn cSy trdn l4n c^o ( g / c / c ) cao hon ch^ dfl ego nhjp dfl d3 trfen ca hai d6ng vfl tinh (DVO. DVT RRIV 3 td ra d&p ling tdt vdi nhjp dfl qio th^p vA cdc nghidm thiic d4 d i u c6 sdn lu(;mg cao hon cdc nghidm thuc d3, trong d6 ddp ling tdt nh^t b nghidm tiic d4 kich thich 6 Idn/nSm. Nhip dfl ego d3 ciia dflng vfl tinh PB 260 cd b i i u hi^n nSng sufit tdt hem, trong dd n g h i | m thiic kich thich 6 1 ^ / n d m la biiu h i | n tich cue nh^t, dat 2996 k g / h a / 2 nSm, tang 33% so vfli ddi chiing. Di§n b i l n cdc chi tiflu sinh ly mii dudd anh huong cOia nhip dfl cao vd t i n sd kich thich cung dirgrc ghi nhdn. Sau hai ndm thirc hi^n cho th^y cac nghi?m thiic CO bfli thudc kich thich d i u co b i i u hifln su hoat dflng tich cue ciia h § thdng dng mu thflng qua mflt sd chi tieu sinh 1^ n h u hdm lugng thiols, ldn vfl ca d i u cao hon so vfli ddi chiing, trong khi hdm lirgng duoiig thi thap hon. D i l u ndy cho thdy kich thich da ldm gia tang sii hoat dflng cua h^ thdng dng mu trong qud trinh b i l n duong tdi tao mii. T;^ 1^ khfl mat cao thdp, dirdi 296.
T u khfla: CSy cao su, dong vd tinh, chddd cao, sinh iymu, nang suat.
L B A T VJilV BE Loai d^t Dat xam bac mau.
Tir khi cao su duoc trong va thu hoach d quy md Ndm trong: 2002 va 2003, n3m md cao: 4/2008.
thuong mai, da co nhi^u bidn phap duoc ap dung vdi p j ^ ^ ^ g pl^^p ^ ^ ^ g . g^^ 2 t ^ g la.
muc dich nang cao nang suat vudn cay, trong dd ky thuat thu hoach mu Xk mdt trong nhOng bidn phdp quan trpng. Qua nhieu nam, da co nhi^u tien bo trong
ky thuat thu hoach mu da duoc dua ra, trong dd vide Qui md thi nghidm: 96 ha.
xac dinh che dd thu hoach dugc dua ldn hang dau. D^ Vanh m o cao: > 47 cm.
phat huy ti^m nang san lupng cua vudn cao su, ti-en ,-.. , . „ „ . , , . ,.•.. . „ „ , ,
^ , •' ^, J , , , , , . , Do cao m a cao: l,o m cach mat dat; l,z m cach
moi dong vd tinh can cd chd dp thu hoach mu thich ^^^ ^ ^ . hpp, hi do CO th^ thu dupe san luong t6i da, han chd
anh hudng d ^ tinh trang sinh ly mu va dam bao chu Th^^c kich thich: Ethephon nong dp 2,5%.
ky kinh te ciia vudn cily. Do v4y, vide nghidn cuu xac 2. Phuong phdp nghidn cuu dinh ch^ dp cao thich hpp cho cac ddng vd tinh mdi Id ^ Bd tn thi nghiem rat cin thi^t Dudi day la k^t qua nghidn ciru xdc djnh
chi dd cao phii hgp cho hai ddng vd tinh RRIV 3 vd PB 260 trdn vudn cdy t a tai Ddng Nam bd.
M$t dp trong: 555 cay/ha, khoang each trong: 3 x 6 m .
Nghidn cuu dupe ti^n hdnh trdn hai ddng vd tinh RRIV 3 va PB 260, hioi c^o 1-3 tai Id 65, 37 vd 38 thudc Ndng trudng Thanh An, Cdng ty LIIW DUNG VA PHMNG PHAP N6lll£N CIJU T N H H M T V C S D i u Tie'ng. C 4 c c j y t r o n g t h i n g h i e m l . V § t l i § U D g h i 6 n c i i u d u g c c^o t h e o c h ^ d p c a o ngiia t r M m a t BO-1 v a i D o n g vo t i n h : RRIV 3 v a P B 260. c h i f e d a i m i e n g c a o S / 2 , n h i p d o c a o d 3 h o J c d 4 , k i c h Ihich b S n g e t h e p h o n 2,5% voi 0, 4, 6, 8 l a n / n a m . T h i n g h i d m d u p e b o t r i t h e o k i ^ u k h 6 i d a y dii h o a n 'Vi?nNgliiSn ciiu Cao s u V i j t Nam t o a n n g a u nhiSn ( R C B D : R a n d o m i z e d C o m p l e t e
NONG NGHIEP VA PHAT TRIEN NONG THON - KV- 2 - THANG 10/2012 25
KHOA H Q C C 6 N G N 0 H |
Block Design) vdi 8 nghidm thiic vdi 3 1 ^ l$p Igi cd tdng s6 24 d ca sa (m6i d ca sb Id 1 phdn ego = 350 cdy). NOi dung cdc nghidm thiic nhu sau:
- NT I: S/2 D d3 6d/7 10m/12. ET 2,5% Pa 0/y (doi chiing, khdng bdi kich thich).
- NT 11: S/2 D d3 6d/7 lOm/12. ET 2,5% Pa 4/y (kich thich thdng 5,6,11,12)
- NT III: S/2 D d3 6d/7 lOm/12 . ET 2,5% Pa 6/y (kich thich ihdng 5,6,9.10,11,12).
- NT IV: S/2 D d3 6d/7 lOm/12. ET 2,5% Pa 8/y (kich thich thdng 5,6,7,8,9,10,11,12).
- NT V: S/2 D d4 6d/7 lOm/12. (d6i chung, khdng bdi kich thich).
- NT VI: S/2 D d4 6d/7 lOm/12. ET 2,5% Pa 4/y (kichtiiichtiidng5,6,ll,12).
- NT VII: S/2 D d4 6d/7 lOm/12. ET 2,5% Pa 6/y (kich thich thdng 5,6,9,10,11,12).
- NT Vin: S/2 D d4 6d/7 lOm/12. ET 2,5% Pa 8/y Odch thich thdng 5,6,7,8,9,10,11,12).
Ghi chii: S/2 : cao nua vdng thin; D (down): c^
mieng didp (mi^ng ngua); d3 hoSc d4:1 ngiy c^o nghi 2 hoic 3 ngay 6d/7:1 tuin 7 ngay cao 6 ngay. nghi ngiy chu nhit. lOm/12: C$o 10 thing/nim (m&c^o tir cudi thing 3 den thing 1 nim sau); ET: Kich thich ethephon hoat chdt 2,5% ai. Pa: bdi tr6n vd tii sinh khdng bdc mu dSy
b. Chitiiu quan trie vi tdn sd'guan trie - San lupng: Theo ddi san lugng mii nuoc vd mii tap ding nhdt cao. Tinh ndng suat cd th^ trdn mdi ldn c?o (g/c/c: gram/cay/cgo); nSng sudt cd th^ trdn nam (kg/cdy/ndm); vd ndng su^t q u ^ thi (kg/ha/ndm).
- Ham lugng cao su khd (DRC): Quan trdc 2 lan/thang O^y rnfai b ldn c^io ngay h-udc vd sau kich thich).
- Sinh tniong: Do vanh thdn (chu vi) a dO cao 1,5 met each mdt ddt 1 Idn/nSm vao thdng 12 hdng ndm.
- Khd mat cao: Quan trAc 1 Idn/thdng (vdo khoang ngdy 10 - 20 hdng thdng).
- Cdc chi tidu sinh ly mu: Hdm lugng duong (sucroza), ldn vd ca (Pi), thiols (RSH) vd ham lugng chat khd (TSC) dugc l^y mSu vd phdn tich hdng thdng theo phuong phdp l^y mau tidu chuSn ngdnh s6 10 TCN 762:2006 va 11TCN 762:2006.
•.KfrquAvAitiAoLuAN
1. Anh hti6ng cCia ch^ dO c^o d^n ndng s u ^ a. Ddng vd tinh RRfVS
K^t qud tir bdng 1 cho th^y, trong hai ndm ddu m^ 090, trung binh ndng suA cd th^ ti-dn m6i Un qio (g/c/c) cHa cdc nghi§m thiic ego d4 cao hon cdc nghidm thiic ego d3, tuang ting Id 41,6 g so vdi 28,8 g.
Trong CLing nhjp d$ 090 d4, cdc nghi$m thiic cd b6i thuric kich thich cho ndng su^t cao hon vd khdc bi^t cd y nghla thdng kd so vdi 6.6\ chCmg (khdng b'ch thfch). Cdc nghi$m thiic c^o d3 cQng c6 k^t qud tuong ti;, nhimg giOa cdc nghidm thiic kich thich vd ddi chiing khdc bi$t khdng c6 y nghla th6ng kd. Dilu niy cho thaiy ddng vO tinh RRIV 3 c6 khd ndng thich img vdi nhjp do th^p vd vi$c gidm nhjp dO c^o hi d3 sang d4 k^t hgp kich thich td ra hi^u qud, nang su^ mu (g/c/c) gia tdng khd tdt D6i vdi ddng vd tinh ndy khi gidm nhip <3$ c^o cdy cd thdi gian tdi t^o mii ddi Hon giua hai ldn c^o dua din ndng suit tdng cao (Chong kewi vd Sivakumaran, 1993).
Ddi vdi cdc nghidm thiic dp dimg chi dO cao d3 ndng sudt giiia cdc nghidm thiic cd kich thich (4,6 vd 8 Idn/ndm) khdc nhau khdng ddng k^, trong dd cao nh^t Id nghidm thiic kich thich 8 Un/nam voi ndng sudt d^t 30,8 g / c / c . Kit qud nay cho th^y khi ap dung nhip ^d d3 kich thich tii 4 - 8 iSn/ndm thi sd lan kich thich chua anh huong rd d i n ndng sudt Ddi vdi nhjp do ego thc(p d4 ciing tuong txf, ndng suit dudng.
nhu khdng gia tdng theo sd lin kich thich md lai cho ndng sudt cao n h i t 6 tin sd kich thich 6 Idn/ndm (dgt 128 g / c / c ) vd vugt hon ca nghidm thirc kich thich 8 lln/ndm (124 g/c/c). M$c dii khdng t^o dupe sv khdc bi$t cd y nghia thdng kd so vdi hai tdn sd kich thich cdn l^i nhung tin sd kich thich 6 lln/ndm dd t h i hi$n tinh vugt trdi b^ng tiii nghidm ndy.
Dilu ddng chii y Id, ddt vdi nhjp dd d4 cd sd l4n C90 it hon so vdi nhip ^0 d3 (tuong ling Id 123 vd 162 lin c^o trong 2 ndm) nhung ndng suit quin thi trong 2 ndm (kg/ha/2 ndm) cua c h i dO c^o d4 luon cao han c h i dd c^io d3 b cung mfii t i n sd kich ttiich. Ndi b^t la nghidm thiic nhip ^9 cao d4 vdi tin sd kich thich 6 lln/ndm dat ndng suat cao nhit (2.277 k g / h a / 2 ndm). Kit qud cung cho thiy 3 nghidm thiic ling dung kich thich ciia nhjp dO c^o d4 d^u cho nang suit cao hon vd khdc bidt cd y nghia thdng kl so vdi ddi chiing. Trong khi dr nhjp dd cao d3 chi c6
26
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 2 - THANG 10/2012'^
KHOA HQC C 6 N 0 M O H I
I n sd kich thich 8 lln/nam la cd sy khdc bi^t cd y ighia thdng kd so vdi nghidm tiiiic ddi chimg (2072 kg so vdi 1690 kg).
Sd li^u kdt qua v^ hdm lugng cao su khd (DRC) sau 2 ndm diu md cao cho thiy, cdc nghidm thiic nhip dd cao d4 (dao ddng tir 29,4% ddn 32,2%) cao hon nhip dg cao d3 (dao ddng tir 28,1% ddn 30,9%) vd cdc nghiem thiic cd kich thich ddu cd hdm lugng cao su
khd thip hon ddi chiing. Rd rdng kich thich vdi ca chd kdo ddi thdi gian chiy mil, tdng h^ sd pha lodng ndn da ldm hdm lugng DRC cua cdc nghidm thiic ndy gidm xudng. Mdc dii cd sir khdc bidt cd y nghia thdng kd so vdi nghidm thiic ddi chiing nhung hdm lugng DRC ciia cdc nghidm thirc kich thich van giii d mire binh thudng vd ddu trdn 28%.
Bing Chiti«u
g / c / c
kg/pc/ngay kg/cay/2 nSm
kg/ha/2 nam
DRC(%)
.. Ndng suit Ch^d«
1/2S d/3 l / 2 S d / 4 l / 2 S d / 3 1/2S d/4 1/2S d/3 1/2S d/4 1/2S d / 3 l / 2 S d / 4 l / 2 S d / 3 l / 2 S d / 4
vk h ^ lu^mg DRC cila DVT RRIV 3 rong hai nam 2008 vi 2009 Tin s6 kich thich
0/y (d/c) 25,6' (100) 35,2'«
(100) 9,1' 12,7'
4,2' 4,2' 1.690=
(100) 1.752''
(100) 30,9' 32,2-
4/y 29,5'' (115) 42,5"' (121) 10,8'' 15,5- 4,8"' 5,1' 1.978">«
(117) 2.139"
(122) 29,9"
31,1' 6/y 29,2'' (114) 44,9- (128) 10,6>«
16,4"
4,7"
5,4"
1.954"'' (116) 2.277"
(130) 28,8'' 30,0'''
8/y
11
43,7' (124) 11,4'' 16,1' 4,9"' 5,3"
2072-' (123) 2.224'
(127) 28,1' 29,4"
TB
28,8 41,6 10,5 15,2 4,7 5,0 1.923 2.098 29,4 30,2
LSD„,K
7,44
2,69 0,89
380,7
1,05 Glu chu: - Cac gia tri titn Cling chi tiiu aJa cac NT CO cung diu cii khdng a^ khic bi$t thdng ke; sd trong () chi phin trim so vdi dd'i chung; Pc: Phan cao; trung binh sdciycao/ha = 408 cay; trung binh sd ciy cao/phan cao =358 cay; sd lit cao d3 = 162, sd lit cao d4 = 123.
b. Ddng vd tinh PB 260
Qua hai ndm dau thuc hidn b-dn DVT PB 260 cho thiy cdc chi tieu vd ndng suit ca thd fe/c/c), ndng suit quan thd (kg/ha/2 ndm) cua cdc nghidm
Bang 2. Ndng suit cua DVT PB 260 trong hai ndm 2008 vd 2009
thirc cd kich thich ddu cao hon va khdc biet cd y nghia thdng kd so vdi ddi chiing khong kich thich (Bang 2).
Chi tieu
g / c / c
kg/pc/ngay
kg/cay/2 nam Ch^dO
1/2S d / 3 1/2S d/4 1/2S d / 3 1/2S d/4 1/2S d / 3
Tin sd kich thich 0/y
(d/c) 34,6 e (100) 38,5 d (100) 13,0 e 14,5 d 5,6 e
4/y 40,1 cd
(116) 47,1 ab
(122) 15,1 cd 17,7 ab 6,5 be
6/y 43,3 be
(125) 50,3 a (131) 16,3 be
18,9 a 7,0 ab
8/y 44,9 b
(130) 50,0 a (130) 16,9 b 18,9 a 7,3 a
TB
40,7 46,5 15,4 17,5 6,6
LSD^K
3,87
1,46
0,51
N 6 N G NGHIEP V A PHAT TRIEN N 6 N G THON - KY 2 - T H A N G 10/2012
27
KHOA H9C C 6 M 0 MOHj
kg/ha/2 n a m
D R C (96) 1/2S
d/4 1/2S d/3 1/2S d/4 1/2S d/3 1/2S d/4
4,7 f 2392 d (100) 2010 e (100) 30,9 b
32,7 a 5,7 de 2776 b (116) 2452 ed
(122) 29,1c
30,6 b 6,2 cd 2996 a (125) 2622 be (131) 28,7 c
30,2 b e.lde 3105 a (130) 2620 be
(130) 28,5 c
30,1b 5,7
2817,2
2425,9
29,3
30,9 216,7
0,91
Ghi chd: • Gii Iri Irong cung 1 chi tidu cua cic nghidm thuced cung 1 chd cii khdng cd khic bi^t thdng kd. Sd trong () chi phin trdm so vdi ddi chiing; Pc: FhAn cao: trung binh s6 ciy cao/phdn c^' 377 ciy: ttuag binh sdciycao/ha - 427ciy: sdlitcfo d/3 -162. Sdlitc^o d/4 -122
So sanh giua nhjp dO cao d3 va d4 eho thiy nang suit timg ea th^ trong m6i ldn C90 (g/c/e) vd nang suat trung binh tr6n phdn eao trong ngiy (kg/pe/ngay) khi C90 nhjp dO thip d4 lu6n cao hon nhip do c^o d3 6 eac tin s6 kich thich. Tuy nhien, miic gia tang nay khdng each bi^t rO nhu trfin d6ng vo tinh RRIV 3. d nhip dO c?o d3 du6ng nhu tin s6 kich thich c6 mdi tuong quan thuan vdi nang suit, trong dd nghiem thuc kich thich 8 lan/nam cho nang suit eao nhat va cao hon so vdi ddi chung 30%. Trong khi d nhip d6 cao d4 nglii^m thiic kich thich 6 lan/nam dat tuong duong nghidm thiic kich thich 8 lan/nam (tuong ling la 50,3 g / c / c va 50,0 g / c / c ) .
M5e dil nang suit ea t h i (g/c/c) cua nhjp dO cao d4 eao hon so vdi d3, nhung do ed sd lin ego it hon n4n nang suit quin t h i (kg/ha/2 nam) eiia nhjp do cao d4 thip hon so vdi nhjp dO cao d3 d ciing moi tan sd kieh thich. Nhjp dd ego d3, kich thich 6 va 8 lan/nam cho kdt qua tdt nhit, tang 25-30* so ddi chiing (2.966 va 3.105 kg/ha/2 nam). Tuy nhidn giOa 2 tan sd kich thich nay diu khdng cd su khac bi|t thdng kl.
Cimg vdi nhflng thay ddi v l mjt nang suit, hdm luong cao su khd ciia DVT PB 260 cung cd nhOng biln ddi nhit dinh dudi tdc dOng eua thudc kich tiiich va nhip do ego. Cdc nghidm thilc bdi thudc kich thich diu ed ham lupng eao su khd thip hon dpi chiing vd cd biiu hiin gidm din Iheo su gia tdng tdn sd kich thieh. Cdc nghi|m Ihiic cao nhjp dd thip d4 cd hdm luong eao su khd eao hon nhjp dO cao d3. Trung binh d nhip do cao d3 cd hdm lupng DRC % dao ddng tir 28,5 - 30,9« vd d4 dao dOng tir 30,1 - 32,7%.
Tdm lai: Kit qua sau hai nam thi,te h i | n cho thiy ddi vdi ddng vd tinh RRIV 3 nhip i d ego d4 k i t h(?p
vdi kich thich 6 lln/nam biiu hi|n tich cue nhdt v^
nang suit ca t h i (g/c/c) cung nhu nang suit qudn thi (kg/ha/nam). Trong khi nhjp do ego d3 kit hpp kieh thich 6 hode 8 Idn/nam trdn ddng vd tinh PB 260 Id thich hpp, bdi le 2 chd dd ego ndy cho sin lupng tdt nhit (tuong ling Id 2.966 kg/2 ndm va 3.10S kg/2 nam).
2. Anh hudng cua c h i dd c ^ din diin biln nang suit g / c / c qua cdc thdng
a. Ddng vd tinh RRIV 3
Trong giai dogn ddu md ego (thdng 5/2008), nang suit izlclc) ciia cdc nghidm thiic diu d miic thip (Dd thi 1)- Tuy vdy, budc sang giai dogn kidi thich diu tiin (thdng 6/2008) ndng suit tir cac nghidm thuc cd kieh thich trin cd hai nhip dp cao d i u cd biiu h i | n gia tdng. D i n dpt kich thich thii 2 (thdng 7/2008) si; ddp img vdi kich thich ldng ISn ddng k l , nhip dd ego d3 tang tir 15 - 51* so vdi doi chiing va nhjp dd ego d4 tang tir 29 - 41*. Qua dd thi eho thiy tit thang 7 din thdng 10/2008 ndng suit ciia cdc nghidm thuc d4 gia tdng d i u d$n qua cdc t h ^ vd cd sv gia tang mgnh d thdng 11 vd thdng 12 vd diy CQng Id nhimg thdng cho sdn lupng cao nhdt trong nam, edn ddi vdi cdc nghi|m thiic d3 cd miic ldng nang suit thip hon d4 k l ed nhung nghidm thiic ci kieh thieh vd tir thdng 7/2008 din cudi nam nSng suit ciia cdc nghi|m thiic d3 ddu thip hon so vdi cic nghidm thiic d4. DJc bidt, ndng suit cua nghifm thiic d3 kich thich 8 lln/ndm (kich thich vdo cic thdng 5, 6, 7, 8, 9,10,11 vd 12) trong thdng 11,12 W sut gidm vd t h i p hon cd ddi chiing. Khi budc sang thdng 1/2009, ddy Id giai dogn cudi miia cao, cdy 1^
diu ed biiu h i | n tut gidm ndng suit trin cd hai aliiP do cao d3 vd d4, do c i y chuin bj cho qud trinh qu^
28
NdNG NGHIf P VA PHAT TRIEN N 6 N G THON - K^ 2 - THANG 10/2012
KHOA Hpc C 6 N 0 NOHfe
ddng, liic dd h i u nhu si^ tdi smh mu tai cho kdt thiic, ho^t ddng bien dudng chdm d i n va mpt sd thdng sd sinh 1^, sinh hda khdc cd xu hudng tich tu lai vd din ddn ndng suit thip.
Kdt qua d ndm cao thii 2 cung tuang tu, trung binh ndng suit cd thd (g/c/c) cua cdc nghidm thiic ddu cd diem khdi diu thip, nhung sang thdng 6/2009 ndng suit cua cdc nghidm thiic ddu gia tdng manh. Trong dd cdc nghidm thvic cao d4 cd kich thich cho ndng suit g / c / c cao hon ddi chiing vd cdc nghidm thiic d3. Nhin chung, cdc nghidm thiic ddu cd ndng suit giam trong thdng 7 vd giu b miic dn dinh ddn thang 9; ndng suit lai tdng cao tir thdng 10 ddn 12, trong dd tdng rd nhat Id cdc nghidm thiic d4 cd kich thich. Cdc nghidm thiic d3 cung cd su gia tdng ndng suit trong giai doan nay nhung d miic t h ^ ban.
tdng rd r^t vd sau dd lai giam vao cudi miia cao (1/2009).
Sang ndm 2009 didn bidn cung tuang tu nhu ndm 2008 nhung vdi khdi didm cao hon vd d^ic bidt la ndng suit tdng manh trong thdng 6 vd giam trong thdng 7 vd thdng 8. Trong thdi gian ndy nhung nghidm thiic cd kich thich (nghidm thiic d3 va d4 kich thich 8 lln/ndm) ndng suit gidm nh? hon va duy tri d miic on djnh trong khi cdc nghidm thiic khdng kich thich ndng suit giam manh. Tir thdng 9 ddn thdng 12 cdc nghidm thuc dupe kich thich ndng suit gia tdng ddng kd, d$c bidt la cdc nghidm thiic cao d4.
Nhin chung cdc nghidm thiic d4 ludn cho ndng suit cao han cdc nghidm thiic d3 vd cdc nghidm thiic kich thich ludn cho ndng suit cao hon cdc nghidm thiic ddi chiing qua cdc thdng trong hai nam 2008 va 2009.
Dd thi 1- Didn bidn ndng suit cd thd (g/c/c) qua cdc thdng trong ndm 2008 vd 2009 trtn DVTRRIV3
b. Ddng vd tinh PB 260
Dien bidn tnmg binh ndng suit mii khd (g/c/c) qua cdc thang trong hai ndm dau thuc hidn trdn ddng vd tinh PB 260 duoc trinh bay a dd thi 2. Sd lidu cho thiy, diu miia ndng suit ttiap, chi dao ddng tir 20,1 - 22,0 g / c / c d nhip dd c^o d3 vd tir 14,6 - 17,6 g / c / c d nhip dd cao d4 va khdng cd su khac bi^t ddng kd giiia cdc nghiem thiic. Ddn thang 6 va thang 7 ndng ' suit gia tdng manh trdn cdc nghidm thiic, day vira la ' su gia tdng ndng suit theo miia vu, ddng thdi cOng la ' kdt qua ddp ung ciia 2 d(?t kich thich diu ndm. Tir ' thdng 8 ddn thang 11, cdc nghidm thiic cd kich thich ' vdn tidp tac giu mire tdng ddu, trong khi cdc nghidm i thiic cdn l?i khdng cd su gia tdng dang kd. Tii thdng
\ 11, san lu^ng cua hiu hdt cdc nghidm thirc ddu gia
Dd thi 2. Didn bidn ndng suit cd tiid (g/c/c) qua cdc thdng trong ndm 2008 vd 2009 trdn DVT PB 260
3. Didn bidn ndng suit (kg/ha/thdn^ qua cdc thdng trong hai ndm diu mdr c^o
a. Ddng vd tinh RRfVS
Nham theo ddi didn bidn ndng suit quan thd qua cdc thdng, sd lidu ndng suit (kg/ha/thang) da dugc tinh todn vd trinh bdy d dd thj 3. Ket qua cho thiy trong ndm 2008, cac nghidm thiic d cd hai nhip dp cao d3 vd d4 ddu cd bidu hidn tdng dan vd cudi ndm vd d^t dinh cao nhit vao thdng 12 va giua cdc nghidm thiic ndng suit kg/ha khdng cd su khac bidt dang kd.
Ddn ndm 2009, tai didm xuit phdt ddu miia cao tir khoang 7 0 - 1 1 0 kg/ha, ndng suit da tdng cao trong thdng 6 d hau hdt cdc nghidm sau dd ^ a m nhe ddn thdng 9 va tdng trd lai tir thdng 10 -12. kdt qua cung
\ N 6 N G NGHIEP V A PHAT TRIEN N 6 N G THON - K\' 2 - THANG 10/2012 29
KHOA Hgc C 6 N 0 NOHt
eho thiy cdc nghidm thiic su dijng kich thich ludn cho nang suit cao hon nghidm thiic ddi chung khdng kieh thich vd nghidm thirc ego d4 cho ndng suit cao hon cdc nghidm thuc d3 qua d e thdng, dgc bidt * nhiing thdng cd sir dyng kich thich.
b. Ddng vd linh PB 260
HKI> >
! • : • , • > - '
/ . I : l ! •-•
/U'^td^'-^ f
Do tlii 3. Di^n bif'ri nfijig suit kg/ha trong h;ii nani 200« vi 2009 Iri'ii DVI" R]UV 3
Dd thi 4. Didn biln ndng suit kg/ha trong hai ndm 2008 vd 2009 trin DVTPB 260 Didn biln ndng suit kg/ha/thdng qua edc thdng trong hai ndm (2008-2009) cho thiy, cdc nghi|m thiie su dung kich thich vdi cdc tdn sd khde nhau trong ndm trdn ca 2 nhjp dp cao d3 vd d4 luOn cao hon nghidm thiic khdng bOi kich thieh (ddi chiing). Cdc nghiim thiic cao d3 kieh thich tir 4 - 8 lan/nam ludn cho nang suit quin t h i (kg/ha/thdng) cao hon cdc nghiim thiic cao d4 cd cimg tin sd kieh thich. Chinh vi sd ldn cao trong thdng cua c h i dO ego d4 it hon so vdi d3 nin vide gia tdng ndng suit ea t h i trdn edc nghidm thiic ego d4 khdng du bil ddp cho vi|e gidm sd lin ego. Vi vdy nang suit (kg/ha/thdng) ciia edc
nghidm thiic ego d3 ludn cao hon cdc nghidm thiic c g o d 4 ( D d t h i 4 ) .
4. Didn bidn hdm lupng cao su khd (DROQ qiu cdc thdng
a. Ddng vd tinh RRIV 3
Didn biln hdm lupng cao su khd (DRC) qua cic thdng trong hai nam ddu md ego d DVT RRIV 3 thj hidn trong dd thj 5. Qua dd thi cho thiy, hdm lupng DRC eua cdc nghidm thiic b cd hai nhjp dd ego d3 vi d4 ddu cao d ddu miia ego, trung binh tir 32,9% - 42,1% nhung sau dd gidm mgnh tir thdng 6 din thdiig#
8. Trong nhimg thdng tilp theo hdm lupng DRC giu miic dn djnh hodc gidm nh? eho din cudi nam. YJA qud cQng cho thiy hdm lupng DRC gidm d cic nghidm thiic cd bdi thudc kich thich, do vdy nhiing thdng ed bdi thudc kich thieh DRC eiia edc nghidm thiic ndy ludn thip hon cdc nghidm thiic ddi chung vd tin sd kieh thich cdng eao thi hdm lupng DRC cdng thip. Nhip dd ego ciing cd dnh huong rd din hdm lupng DRC; sd Udu cho thiy d cdc nghi|m thiic ego d4 hdm lupng DRC ludn eao hon cdc nghidm thiie ego d3, dilu ndy cd t h i do ego d4 cd thdi gian nghi ego ddi hon n i n ed thdi gign tdi sinh mu tdt hon.
Dd thi 5. Didn bl&i KAiL lupRSSo su khd DRC (X) trong hai ndm 2008 vd 2009 trin DVT RRIV 3
b. Ddng vd tinh PB 260
Nhin chung, didn biln hdm lupng DRC cua dong v6 tinh PB 260 ciing tuong bf nhu eua ddng vd link, RRIV 3. Hdm lupng DRC d cdc nghidm thiic diu can d ddu miia ego, sau dd gidm mgnh trong nhiing thdng sau dd (Ihdng 6 thdng 7) vd dn djnh eho ih cudi nam. Cac nghidm thiic d4 cd hdm lupng DRC cao hon edc nghidm thiic d3 vd trong cimg nhjp iK 30
NONG NGHIEP VA PHAT TRIEN NONG THdN - KV' 2 - THANG 10/2012
KHOA HOC C O N G NGHl
ego thi nhiing nghi|m thiic cd kich thich hdm lupng DRC ludn thip hon nghidm thiic khOng kich thich (Do Ihi 6).
Qua cae thdng trong ndm, hdu h i t edc nghi|m thiic ddu cd ham lupng DRC d miie binh thudng, ehi ridng trong thdng 8/2008 hdm lupng DRC cua nghidm thiic d3 kieh thieh 8 lan/nam Id khd Ihip, ehi khoang 24«.
Dd thi 6. Didn bidn hdm lupng cao su khd DRC («) trong hai ndm 2008 vd 2009 trin DVT PB 260
5. Anh huong cda e h l d6 khai thdc din cdc chi lieu sinh l^ mu trin hai ddng vO tinh RRIV 3 vd PB 260
Bdn thong sd sinh ly mii, bao gdm: ham lupng dudng, ham lupng cae nhdm thiols (R-SH), Idn vo co (Pi) va ham lupng chat kho tong sd (TSC), la bdn thOng sd quan trpng cung cap hau nhu diy du cdc thong tin thiet yiu d l danh gid tinh trgng sinh ly ciia
; h i thdng maeh mu Oaeob, 1987). Kit qua v l edc chi I heu sinh ly mii trong thi nghiim t e n hai ddng vO linh RRIV 3 vd PB 260 dupe trinh bdy d phii luc 1 vd , 2 .
Kit qud cho thdy, trudc khi kieh thich tinh trang ' h i thdng dng mu cua tat ca cdc nghiim thiic trin ca I hai ddng vO tinh hogt ddng d miie binh thudng vd I hau nhu khOng ed su khdc biet ddng k l . Qua 2 nam theo doi thi nghiim cho thiy tinh trang sinh Iy mii eiia cac nghiSm fhiic ed ling dung kich thich vin duy
> tri a miie tdt Dang luu # nhat Id hdm lupng thiols (R- (SH) eiia cdc nghiim thiic kieh thich d i u cao vd i' khdng cd sir khdc bidt so vdi ddi chiing trdn cd hai (ddng vd tinh. Ddy Id su t h i hiin hogt dOng tich cue I'vd ben viing cua h | thdng dng mu, bdi vi thiols cao
« giiip bao v l maeh md vd duy tri ddng chay, giiip gia
tdng nang suit. Rilng ddi vdi ddng vo tinh PB 260, cdc nghidm thiic cao d4 k i t hpp kieh thieh cd hdm lupng thiols thdp hon cdc nghi|m thiic ego d3 tir 0,02 - 0,07 mM vd khde bi|t so vdi ddi chiing. Bidu h i | n ndy tuong tp nhu k i t qud eua nhiing nghidn ciiu trudc day (Dinh Xudn Trudng, 2003), dilu ndy cd thi thiy dupe sir ddp ling kdm vdi nang suit eua nhjp dO eao d4 trin ddng vO tinh ndy.
Hdm lupng lan vd co (Pi) trong mgch mil phdn dnh khd ndng bidn duOng trong mgeh md, do vdy khi hdm lupng Pi tdng eao dua din ndng suit tang. Trin thi nghiim ddng vO tinh PB 260 cdc nghiim thiic ego d3 cd hdm lupng ldn vO co eao hem cdc nghi|m thiie ego d4, dilu ndy phii hpp vdi bidu hi|n eao hon vl nang suit ciia cae nghidm thiic cao d3 so vdi cae nghiim thirc ego d4. Ngupe Igi, ddi vdi ddng vd tinh RRIV 3 thi cdc nghi|m thiic cao d4 ed hdm lupng lan vd CO phdn ndo cao hon cdc nghiim thiic cao d3, vi thi cdc nghiim thiie ndy cho nang sudt tich cue hem.
Kit qua d phu lue 1 va 2 cho thay r6 cd hai nghiim Ihiic ddi chiing cao d3 va d4 trdn hai ddng vO tinh diu ed hdm lupng dudng cao, nhung lai cd hdm lupng Pi Ihip hon edc nghiim thiic cd bOi thudc kich thieh. Dieu nay cho thiy cay biln dupng kem nin khd nang su dung dudng kem tich cue ddn din nang sudt thdp. Tuy vgy, khi dupe tac dpng kieh thich tir 4 - 6 Idn/nam, tinh trang sinh ly cua eay ed nhiing phan img tich cue trin cd hai nhip dO cao d3 vd d4, khi dd cay sii dung dudng tdt hon vd di kem vdi hoat dOng bien duong mgnh, vi thd nang sudt eiia cdc nghiim Ihiic nay cd biiu h i | n tdt hon (tuong tu k i t qua nghiin eiiu cua Nguyin Nang, 2003). Ngupe Igi, n i u kich thich din 8 Idn/nam thi eay bat ddu ed ddu hi|u phdn ling lai bdng cdch khOng sir dung dudng Idm nguyin li|u d l san sinh mu ma ed xu hirdng lich tu lai nin nang suat c6 phdn suy gidm (php luc 1).
Nhin ehung trin ca hai ddng vO tinh cua thi nghiim nay diu ed su sut giam ham lupng ehdt khO CTSC) sau kich thich so vdi trudc kich ihich. Ro rdng, kich thich da Idm gidm ham lupng chit khO TSC trong q u i hinh ego md (d' Auzac J., 1989). Tuy vdy, miic suy giam hdm lupng TSC eua edc thi nghi|ra ndy Ihi h i | n sp tich cpe; dd Id giam dd nhdt trong md, Idm thudn Ipi cho ddng chay md vd gdp phan tang sdn lupng khi dupe kieh thieh (De Jong, 1953).
Lidn h i vdi diin biln ndng suit (g/c/c) o dd thi 1 va dd th) 2 cho thiy ro vin d l ndy.
N 6 N G NGHIEP V A PHAT TRIEN N O N G THON - KV- 2 - THANG 10/2012
KHOA HQC C 6 N 0 NGHj
6. Anh hudng cua cdc e h l dO ego din khd rajt ego vd sinh trudng Irong ndm 2009
a.Kh6m$tcao
Kit qui qua hai ndm thi nghi|m eho thiy ty 1|
eay khd mdt cao (KMC) trdn hai ddng vd tinh RRIV 3 vd PB 260 d miie thip, trong dd ty l | KMC todn phdn (elp 4) bidn dOng tir 0,13« -1,22% (Bdng 3). Mgc dil edn d miic thap, nhung ty Id KMC todn phdn eua ddng vO tinh PB 260 cd biiu h i | n cao hon ddng vd tinh RRIV 3. Cdc nghiim thiic ego d3 sir dung kich thich tren PB 260 diu ed diu hidu khfl mgt ego eao hon so vdi e h l dd ego d4 cd ciing tin sd kich Ihich,
trong dd d nghi|m thiie ego d3, kich thieh 4 vi S Idn/ndm t^ Id KMC todn phdn cao nhdt (tuong ling 1,15% vd 1,22%).
b. Sinh tnrdng vi hao ddm khi c^o
Trong hai ndm ddu thpe h i | n thi nghi|m, kft qud dr bdng 4 cho thdy giOa cdc nghidm thiic khdng cd sv khdc nhau vd tdng trudng vanh. Giira cic nghiim thuc kich thich vd khdng kieh thich, kl ci nhiing nghidm thiie xir 1^ kieh thieh tii 6 din 8 Idn/ndm diu khdng cd su khdc bi$t thdng k l vl vanh thdn so vdi ddi chiing khdng kich thich trin cd hai ddng vd tinh.
NT
d3,0/y d3,4/y d3,6/y d3,8/y d4, 0/y d4, 4/y d4, 6/y d4, 8/y
idng 1.1Vl|kh( mdt ego trdn hai ddng vd inh cao B jR K l V 3 v d P B2tiU Ddng vd tinh
RR1V3 C l C 2 C 3
1 (0,07)
2 (0,14)
4 (0,28) 2 (0,15)
C 4
2 (0,14) 3 (0,20) 2 (0,13) 2 (0,14) 3 (0,22) 6 (0,42) 5 (0,37)
PB260 C l
1 (0,07) C 2
1 (0,07)
2 (0,14) C 3
1 (0,07) 1 (0,07) 1(0,07)
C 4 6 (0,43) 17 (1,15) 13 (0,96) 18 (1,22) 4(0,27) 2 (0,13) 6 (0,40) 15 (1,09) Ghichu:S6lTongngoScchi%caybikhdmi$ngcao.-i-Cl:c^pl:<25%,-i-C2:Cip2:ta26-50Si,*Ci:
Cap 3: td 51-75%, *C 4: Cap 4: > 76X.
Bdng 4. Tdng trudng vanh thdn vd hao dam ego trong nam 2009 DVT
RRIV3
PB260 Chi tiiu Vanh (cm)
Hao dam/nam Vanh (em)
Hao dam/nam
Nhjp do cao
d3 d4 d3 d4 d3 d4 d3 d4
Sd ldn kich thich 0/y (dc)
52,7 53,4 12,8 10,8 54,2 53,4 13,9 12,0
4/y 52,6 52,9 12,9 12,2 53,9 53,6 13,5 11,9
6/y 53,0 52,4 13,1 11,4 55,3 53,6 13,6 12,1
8/y 53,4 53,5 13,1 11,2 53,9 53,9 14,0 11,3
TB 52,9 53,0 13,0 11,4 54,3 53,6 13,7 11,8
* Ghi chd: So lan C9od4 trung hinh 60 lit c^; sd lin c^/nim d3 tnmg binh 78IitC90.
Nhin chung, niuc dd hao dam ego eua e h l dd ego d4 thdp hon so vdi nhjp dd d3, vi sd Idn ego trong nam eiia d4 Id 60 lat ego, trong khi nhjp dp d3 Id 78 Idt cao. Tmng binh miic hao ddm cua d4 tir 10,8 - 11,8 cm/nam vd ciia d3 Id 13,0 - 13,7 cm/ndm. Nhu
vdy ego d4 s8 tidt kidm dupe vd ego hon vd s i klo dai thdi gign ego trin vd nguyin sinh hon so vdi nhip di d3. Ngodi ra sd lin ego trong ndm cttng cho thdy cjo d4 s i it tdn cdng lao ddng hon so vdi ego d3. Nto vdy, ddi vdi nhiing ddng vd tinh thieh ling vdi nhip^
32
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 2 - THANG 10/2012
KHOA HOC C O N G NGHfi
c?o t h i p n h u D V T RRIV 3 , k h i d p d y n g c h d c a o d 4 sd c h o n d n g s u i t t u o n g d u o n g s o vdi ego d 3 vd m a n g lai n h u n g Igi ich d a n g k d .
nr. KET LUAN
N d n g s u i t c d t h d ( g / c / c ) ciia c d c n g h i d m thiic cd xir ly k i c h t h i c h d d u c a o h o n s o v d i d d i c h u n g k h d n g k i c h t h i c h . Kich t h i c h d a p i m g t d t d d n n d n g s u i t mii n g a y t r o n g n h i m g t h d n g d d u c a o .
N h i p d p c a o d 4 c h o n d n g s u i t c d t h d ( g / c / c ) , cao h o n n h i p d p c a o d 3 t r d n c a 2 D V T .
N h i p d p d 4 trdn d d n g vd t i n h RRIV 3 d d p l i n g tdt k i c h thich d d n n d n g s u i t , t r o n g k h i P B 260 t h d hidn n d n g s u i t c a o d n h i p d d d 3 .
T r d n d d n g vd tinh RRIV 3 n d n g s u i t q u i n t h d ( k g / h a ) ciia c h d d d c ? o d 4 c a o h o n c h d d d c a o d 3 . T r o n g d d , c h d d p c a o n h i p d d d 4 k i c h thich 6 l l n / n d m ( S / 2 d 4 l O m / 1 2 E T 2 , 5 % 6 / y ) c h o n d n g s u i t cao n h a t .
T r d n d d n g vd tinh P B 260, n d n g s u i t q u i n t h d ( k g / h a ) ciia c h d d p c a o d 3 c a o hoTi c h d d d c a o d 4 . T r o n g d d , c h d d d c a o n h i p d p d 3 k i c h thich 6 l a n / n d m ( S / 2 d 3 l O m / 1 2 + 2,5% 6 / y ) t h d h i d n n a n g s u i t tich circ n h a t ^n c h o n d n g s u i t t u o n g d u o n g vdi n g h i e m thiic k i c h t h i c h 8 l a n / n d m .
N h i p d p c a o d 4 tidt kidn d u p e vd c a o vd c d n g lao d d n g h o n s o vdi d 3 . C h u a t h a y c d sir k h d c bidt r d v e t d n g v a n h giiia c a c n g h i d m t h u c vd t ^ Id k h d m d t c a o d c a c n g h i d m thiic, d e u d m i i c t h a p .
Cdc c h i tidu s i n h ly d a p h d n d n h t a c d d n g tich c u e ciia k i c h t h i c h d d n q u d t r i n h b i d n d u d n g tai t a o m u c u a h d tiidng d n g m u t r d n c a 2 d d n g vd t i n h .
V. KNGM
Tidp t u e t h e o d d i t h i n g h i d m t r o n g t h d i g i a n ddi dd ed n h u n g k d t q u a x a c d a n g .
D d i v d i d d n g vd t i n h RRIV 3 , c d t h d l i n g d u n g nhip d d c a o d 4 k d t h p p k i e h t h i c h 6 l a n / n d m trdn fliue n g h i d m didn r d n g d d d d n h g i d s d m k d t q u a . Rieng ddi vdi d d n g vd t i n h P B 260 n d n t h u e h i d n c h d dp e a o d 3 k d t h p p k i c h t h i c h 6 l l n / n d m n g a y tir k h i m d i b i t d a u m d e a o .
TJilLfUTHAMKHAO
1. Do Kim Thdnh vd Kim Thi Thuy (2003). Phan loai kidu hinh eiia ddng vd tinh cao su. Bdo eao trinh bay tai IRRDB Workshop on Exploitation Technology, An Dp 15 -18/12/2003.
2. D6 Kim Thanh vd Nguydn Anh Nghia (1997).
Khao sdt didn bidn ede thdng sd sinh ly mii cay cao su Hevea Brasiliensis qua edc ndm cao. Bdo cdo trinh bay tai hpi thdo khoa hpc vd cao su thidn nhidn cua IRRDB. Thdnh phd Hd Chi Minh, 10/1997.
3. Dinh Xuan Trudng 2003. Nghiin cuu kha ning dip ting chat idch thich md ethephon ciia mdi sd ddng vd tinh cao su tai Lai Khi. Ludn vdn thac si khoa hpc ndng nghidp. Tnrdng Dai hpc Ndng Lam Thanh phd Hd Chi Minh.
4. Nguydn Ndng, 2003. Anh huong liu dai cua chit kich thich mu ethephon din ning suit, tinh trang sinh Iymu trin hai dong vd tinh cao su PB 255, VM 515 trin dat xim mien Dong Nam bd. Luan van thac si khoa hpc ndng nghiep. Trudng Dai hpc Ndng Lam Thanh phd Hd Chi Minh.
5. Nguydn Thuy Hai va Dd Kim Thanh (1993).
Bien thidn miia vu cua cae thdng sd smh ly mu eay cao su Hevea Brasihensis. Bao cdo trinh bay tai SHHTVidn NCCSVN, 1993.
6. d' Auzac J., Jacob J. L and Chrestin H. i Physiology of rubber tree latex. CRC Press, Inc.
Boca Raton, Florida
7. Do Kim Ihanh, 1995. Effects of tapping and stimulation Aequency on performance of yield and selected latex physiological parameter of rubber (Hevea brasiliensis MuelL Arg.) clones RRfM &X) and GT 1. Thesis Submitted in Fulfilment of the Requirements for the Degree of Master of Agricultural Science in the Faculty of Agriculture Umversiti Pertanian Malaysia.
8. d'Auzac (1989). The Hormonal stimulation of latex yield. In d'Auzac, J.; Jacob, J.L; Chrestin, H.
(eds) Physiology of Rubber Tree Latex. Bocaraton, Florida, CRC Press Inc. p: 290.
N 6 N G NGHlfP VA PHAT TRIEN N 6 N G THON - KY 2 - THANG 10/2012 33
KHOA HOC CdNO NOH|
9. Dejong, P. (1955). Stimulation of yield in Hevea yield stimulants. J. Rubb. Res. Inst Malaya, Vol. 17(^) brasiliensis. HI. Further observations on the e^ct of pp.158-16.
INFLUENCE OF TAPPING AND STIMULATION FREQUENCY ON YIELD AND PHYSIOLOGYCAL PARAMETERS OF LATEX ON TWO RUBBER CLONE RRIV3 AND PB 260
Kim Thi Thuy, Do Kim Thanh, Nguyen Tlii Thanh Thao Summary
A study was carried out to examine the effect of low tapping frequecy and stimulation on production and physiology of latex of two mbber clones RRIV 3 and PB 260 for the purpose of finding out the suitable tapping systerms. Results of this research show that tapping system d4 produced higher individual yield (g/t/t gam/tapping/tree) than that of tapping system d3 on two clones. However, the cumulative yield Ocg/ha) for 2 years of tapping system d4 of clone PB 260 is lower that of d3 because of lesser number of tapping of d4. Clone RRIV 3 have a good response to low tapping frequency, so yield of treatments d4 were higher than that of tapping frequency dS, and treatment with 6 times of stimulation per year have the best response in those treatments. Whereas, clone PB260 produces effectively when combine dS tapping frequency with 6 times of sdmulation per year and gets 2996 kg/ha/2 years. It increases by 3396 io comparison with control treatment and this difQrent is significant in statistic. Variadon of physiological indicators of latex under the influence of different tapping systems is recorded. After applying low tapping frequency for two years, some physiological parameters of latex expressed its positive activity, content of thiols and inorganic phosphate of the stimulated treatments are lower than unstimulated control, but there is not any significant difference. Tree panel dryness incidence of two clones is lower than 2 percent Key words: Rubber, done, tapping&equecy.physiohgy of latex, yield.
Ngudi phdn bidn: GS.TS. Nguydn Ngpc Kinh Ngdy nhdn bdi: 27/6/2012
Ngdy thdng qua phdn bi^n: 23/9/2012 Ngdy duy^t ddng: 8/10/2012
34
NONG NGHIEP VA PHAT TRIEN N 6 N G T H 6 N - KY 2 - THANG 10/20l§
KHOA H9C C 6 N 0 NOHt
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