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Xu hudng giam nang suat rimg tidng qua mot sd chu ky kinh doanh dang la mot ydu cau thuc tidn cdn nghidn ciru giai quyet nham phat tri6n lam nghiep ben vung a Viet Nam. Nghien cuu ndy nhdm danh gia anh hudng cua de lai vat lieu hiru co sau khai thac (VLHCSKT) den sinh trudng, nang suat va smh khdi rimg tidng keo la tram (Aauricuiifotmis) qua 3 chu ky (CR) kinh doanh tai Phii Binh, tinh Binh Dmmg. Rimg tidng san xuat d CKI (1995 - 2002), ning tiong thi nghidm CK2 (2002 - 2008) va rimg trong tiii nghiem CK3 (2008 - 2013).
Thi nghidm duoc bd tri tbeo khdi ngiu nhien day du vdi 5 lan lap lai, gom 3 cdng thiic thf nghiem la: (Fl) lay di tiian bo VUICSKT chu k^ 1 va 2; (Fm) de lai VLHCSKT chu ky 1 & 2 va (Fh) dd lai gdp ddi VLHCSKT chu ky 1, de lai VLHCSKT d chu ky 2 va cd bdn lot 300 g supe phdt phat don/cay 16,5% P^Oj (hrong duong 36 kg P/ha). Mgt dp tidng rung 1.667 ciky/ha. Kdt qua cho thdy, dd lai VLHCSKT da lam tang ty Id sdng, sinh tmdng, nang sudt vd sinh khdi rimg tidng keo la tiam a cac chu ky sau. Mac dii tudi ning d chu ky sau fliap hon so vdi chu ky trudc, nhung sau 5 nam rtmg tidng d CK3, thi nghiem thiic Fh la tdt nhat. co trii lupng 185,6 mVha, vuot 2,8% so vdi CK2 180,4 mVha. Nang suat rtmg QVIAI) b CK3 nghidm thuc Fh dat 37.1 mVha/nam so vdi 30,1 m^/ha/nam d CK2, day la mot budc cai thien rat ldn ve nang sudt ning trong. Sinh khdi rimg d CK3 tuong duong vdi CK2 m$c dii tudi rimg thap hon 1 nam. Sinh khdi khd tidn m§t ddt cua nghidm thuc Fh dat 142,8 tdn/ha, vuot 10,2% so vdi Fm (129,5 tdn/ha) va vuot 17,6% so vdi nghidm thdc ddi chdng Fl (121,5 tdn/ha). Nhu vSy, dd lai VLHCSKT da gop phan cai thidn do phi cua dat va n ^ g cao n5ng sudt rung tidng keo M tiam d cdc chu ky sau tidn ddt xam phat tridn tidn phu sa cd d tinh Binh Duong.
Tiikhda: Vat h^u huu ca sau Idiai thac (VLHCSKT), sinh tru&ng, nang suit, sinh idioi rimg.
1 _ 9jij ylm B[ dirge eho la mdt hong nhung nguyen nhan chinh ldm giam dp phi ciia ddt va nang sudt rimg trdng (Pham The Dung va cs, 2012). Do vdy, ky thugt quan ly lap dia tidn tidn bang vide dd lai vdt Ueu huu co sau khai , , , , , , , , ttide (VLHCSKO giiip cai thidn dd phi cua dat vd keo eua ca nuoc men nay khoang 1,1 tneu ha vm chu . , ^^ , ^ * ' » ' i. -^ i
; A l , ' - nang cao nang suat nmg tiong dang Id mot phuong Hidn nay d nudc ta, keo dang Id lodi cdy chu lue
trong hdng rimg cdng nghidp eung cap nguydn lidu cho nganh chd bidn gd. Tong didn tich rimg hdng
thiic quan ly rimg bdn virng qua ede chu ky kinh doanh. Bdi vidt nay gidi thieu kdt qua nghien cuu anh hudng cua vide dd lai VUICSKT ddn t^ Id sdng, smh trudng, nang sudt vd sinh khdi rimg hdng keo Id ham qua cdc ehu k^ kinh doanh.
2. VAT Liu VA PHUDNG PI k^ kinh doanh ngdn 6 - 8 nam vd cd xu hudng ngdy
eang tang (Nambiar & Harwood, 2014). Vide phdt tridn rimg hdng keo da ed nhiing ddng gdp ddng kd hong phat tiien kinh td- xa hdi, gdp phdn giam nhap khau gd, dap ung nhu cdu nguydn lieu eho chd bidn gd ngdy cdng tang eao.
Tuy nhidn, nang suat rimg hdng phu thupe rat
ldn vao ehon gidng, didu kipn lap dia va phuong ttiiic 2.1. Vdt lidu nghidn cihi
quan ly rimg. Su bdn viing san xudt lam nghidp ehinh * ^ ^ ^^^^ ^^hidn cuu: Tram Thuc nghidm Lam Id nang sudt dn dinh vd ngay eang duoc cai thidn qua nghiep Phii Binh, thude Vidn Khoa hge Um nghidp cdc chu ky kinh doanh, didu nay chi cd ttid dat duoc Nam bp tai xa An Bmh, huydn Phii Gido, tinh Binh dua hdn su bdn vung vd sue san xudt cua ddt Trong Duong, ed vi hi tga do dia ly: 10" 52' 12" ddn 11" 30' vi kinh doanh rimg hdng hidn nay, ed xu hudng suy ^^ ^^^ ^^ 106« 20' ddn 1070 06' kinh dp.
giam nang sudt rimg sau nhidu ehu ky kinh doanh * Bit a khu vuc nghien cuu: Id ddt xam vang bdi phuang thiic eanh tac tmyen thdng nhu cay, dot trdn phii sa cd (Aerisol chromic), mdu chat da phien, hay ldy di cdc vat hdu sau khai thde; phuong thiic nay noi dia hinh cao, dinh ddi bdng cd dp ddc 1 - 3°. Ddt cd cau tnie thit set pha cat d tang mat va hong ' Vien Khoa hpc Lam nghi?p Nam bp
N 6 N G NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 1/2015 129
KHOA HOC CbNG NGHE khoang 0 - 20 cm, khong co bi^n ddi nhi^u v6 cau
tnie. Dat chua, co PHH2O trung binh = 4,0 va khong thay doi nhi^u giira cac tang. Bo chua trao doi PHRCI bien dpng 3,98 - 4,00 cho thay dat hoi chua. Ham Iupng cation trao ddi K*, Ca*^ va Mg*^ a muc trung binh va ham lupng dinh duong trong dat ngheo (Cac bon hiiu ca bidn dpng khoang 2%, N < 0,2%, lan d l adu 3 - 8 m g / k g d a t ) .
* Ddi ttrong nghi&n cuu: loai cSy keo la tram trdng thuan loai trdn dat xam vang phat tridn trdn phu sa cd tai Tram Thuc nghiem Lam nghidp Phii Binh, tinh Binh Dupng va dupc danh gia qua 3 chu ky kinh doanh nhu sau:
• Chu k^ 1: trdng nam 1995, khai thac nam 2002 (7 nam).
- Chu ky 2: trpng nam 2002, khai thac nam 2008 (6 nam).
- Chu k^ 3: trdng nam 2008, theo ddi ddn nam 2013 (5 nam).
2.2. Phuong p h ^ nghidn cthi - Phuongphip bd Iri thi nghiem
Thi nghidm duoc bd tri theo khdi ngiu nhidn day dli gdm 3 nghiem thiic va 5 lin lap lai.
Cac nghi&m thiic la;
Fl: My di toan bg VLHCSKT 6 chu ky 1 va 2.
Fm: dd fei VLHCSKT sau khai thac chu ky 1 v4 2.
Fh: de lai gap ddi lupng VLHCSKT a chu kJ' 1, dd jai VLHCSKT p chu ky 2 va cd bdn lot 300 g supe phdt phat don/cay (tupng duong 36 kg P/ha).
Tdng didn tich cua 15 d thi nghidm la 17.280 m^
didn tich mdi d la 1.152 m ' (12 hang x 16 cay/hang)i trong dd didn tich d do ddm la 576 m^ (8 hang x I2' cay/hang = 96 cay), didn tich viing dem la 576 m^
gdm 2 hang cSy bao xung quanh d do ddm.
VLHCSKT p day la tpto bg canh, nggn cay cd dudng kinh < 5 cm, la, vp cay, hpa, qua, cay bui, tham tuoi, tham muc de lai sau khai thac. Tdng lupng sinh khdi khd de lai o CK2 la 20,97 tan/ha va cay bui, tham tuoi 9,87 tan/ha (Kieu Tuan Dat va cs, 2014)!
Toan bd VLHCSKT dupc chat ngan < 1 m va rai deu, khdng ap dung cp gioi h-png lam dat va cham sdc rimg trpng 2 nam dau bang phun thudc diet cp Rpund-up vdi lieu lupng 4 lit/ha trong 2 nam dau.
• Phuongphip thu thip sdlieu - Do dem sinh trudng:
Sd li$u vd sinh trupng, tru lupng, san luong, sinh khdi rimg d chu ky 1, 2 dupc sir dung sd heu cua du an CIFOR (Vu Dmh Hudng va cs, 2008). Rung chu ky 3 dupc do dinh ky 1 nam/lan gdm: ty le sdng (X), Hvn (m), Di3 (cm) va xac dinh trir lupng cua lam phan, Iupng gd thupng phim lay ra va Iugng VLHCSKT dd Iai sau khai thac rimg.
- Thu thap miu sinh khdi trdn mat dit:
Hang nam, p chu k^ 2 va 3, chpn ra 15 diy mlu tidu chuin dai dien chp cac cap kinh ciia lam p h ^ dugc ha dd tinh sinh khdi. Mdi cay dupc c^t Iim 5 doan bang nhau, than, vo, canh, la va hoa qua dupc xac dmh khdi Iupng tupi ngay tai hien trudng va lay miu 0,5 kg cho timg bd phan than cay. Miu dupc say khd d 76°C ddn khi khdi Iupng khdng ddi va can Iai ffi xac dinh sinh khdi khd. Tir sd lidu sinh ciia 15 cay ti6u chuin, thiet lap phupng trinh tupng quan de tinh toan sinh khdi chp ca lam phan, ap dung phupng trinh:
Y^,0682)P«>= (vdi R-0,9885), Irpng dd: Y la tdng sinh khdi khd ciia cay (kg/cay); X Ii dudng kinh ngang nguc (cm) (Vu Dinh Huong & et al., 2004).
- Phinmg phip xuly sdheu
So Udu thu thap dupc x u Iy thep phuong phap thdng kd sinh hpc va su dung Excel 7.0 de tinh toan xu Ijr sd hdu thdng ke v i so sanh giua cac nghiem thiic.
3.KCriHI«VATHAaLltilN
3.1. Dinh g i i ly I^ sdng c i a ciy qua c i c chu kf kinh doanh
Ket qua sp sanh ly Id sdng cua cac nghidm thiic khi ap dung ky thuat quan ly VLHCSKT qua cac chu ky kinh dpanh dupc thd hidn p hinh 1.
S» sanh t^ le song cib cac nghiem thvc qila3chnl^kfaibdoaiih
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KHOA HOC CdNG N G H |
O CKI rimg trdng san xuat keo Id tram khi khai thde d tudi 7 ed ty Id sdng ttidp, chi dat 78,1%. Den CK2 dp dung quan ly VLHCSKT da ldm tang ty Id sdng cua rung ldn 91,3% d nghidm thiie giii lai VLHCSKT, 91,7% d nghidm tiuic giii Iai gdp ddi lugng VLHCSKT va cao hon so vdi ddi ehiing khi lay di ti)dn bg VLHCSKT ty Id sdng chi dat 87.9%. Ket qua ddnh gia ty le sdng d CK3 cung dugc cai thidn so vdi 2 chu k^ kinh doanh trudc dd va nghidm thue Fh
& Fm cd su khdc bidt rd rdt so vdi edng thiic ddi ehung. Nghidm thur cd ty Id song cao nhat la Fh (94,8%), Fm (90,8%), ttiap nhdt la Fl (86,3%) va giiia cac nghidm thuc da cd su khde bidt rd ret ve mat thong kd ^ < 0,001). Dieu ndy cd the ly gidi rdng, vide de lai VLHCSKT da tao ttidnh ldp ttiam ehe phii b^ mat vd giii am cho ddt, lam tang dinh dudng eho dat giup cay khde manh vd ehdng chiu tdt hon vdi di^u kien ngoai eanh tac ddng, giiip ndng eao ty Id sdng cua ning hong d cae chu k^ sau.
3.2. Sinh tnidng dudng kinh (Di^
Ddng thai sinh trudng dudng kinh d vi tri 1,3 m ciia cac nghidm thuc qua edc chu k^ kinh doanh dugc the hidn d hinh 2.
sdm khep tdn va tir tuoi 3 h d di da bat ddu ed su canh tranh ve khdng gian dinh dudng, ndn sinh trudng v^
dudng kinh cd khoang each cham lai va sinh trudng chi^u eao tang manh. O ca hai ehu ky sau thi nghidm thiie Fh ludn cho sinh trudng dudng kinh ldn nhat, ti^p d^n Id nghidm tinic Fm vd ttidp nhat Id Fl. O CK3 sau 5 tuoi dudng kinh d nghidm thiic Fh = 13,2 cm, tuong duong vdi nghidm thiie tot nhat cua rung hong CK2 = 13,5 cm (6 tiidi). Nhu vay, de lai VLHCSKT da gdp phan lam nit ngdn sinh trudng dudng kinh than cay trudc khoang 1 nam.
3.3. Sinh trudng chi^u cao (Hvn)
Ddng thdi sinh trudng chieu cao vut nggn trung binh ciia rung qua cdc chu ky kinh doanh dugc th^
hidn dhinh 3.
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H i n h 2. D O n g t h d i s i n h t r u d n g d u d n g k i n h q u a c d c c h u k ^ k i n h d o a n h
R u n g h o n g c h u k ^ 1 c d m a t d d 833 c d y / h a , s a u 7 n a m t h u h o a e h d u d n g k i n h t r u n g b i n h d a t 14 c m , e a o h o n C K 2 ( r i m g 6 tiidi) v a C K 3 ( n i n g 5 tiioi). O c a 2 e h u k y k i n h d o a n h s a u , d giai d o a n rimg 1 - 3 t u o i thi s i n h t r u d n g v e d u d n g l d n h ed sir k h a e b i e t r d t l d n giiia c a c n g h i e m thiic. D ^ n giai d o a n r i m g 4 • 5 n a m t u d i v d n cd s u k h a c b i e t ed y n g h i a t h d n g k e v e e h i tidu d u d n g k i n h giiia c a e n g h i d m t h i i c , n h u n g e h e n h l d c h t h u h e p h o n s o v d i k h i r t m g c d n n o n . D i e u n a y c h o t h a y , k h i h o n g r i m g d m a t d o 1.667 c a y / h a r i m g
Btffl dpog sinh Inniiig Hvii (m) cua cac n^iieffl due qua 3 diQ 1^ ldnh doanh rung trong k » la fr
H i n h 3 . D O n g Ihdi s i n h t r u d n g c h i ^ c a o q u a c d c c h u k ^ k i n h d o a n h
N h u v a y , q u a e d c c h u k y k i n h d o a n h t h i s i n h t r u d n g c h i ^ u c a o ciia l a m p h d n d u g e c a i ttudn r d t r d r e t Cf C K I cd c h i ^ u c a o c u a l a m p h d n r d t t h d p , c h i d a t 11,7 m s a u 7 n d m . D ^ n C K 2 c h i ^ u c a o n g h i d m t h i i e t o t n h a t d a t 16,7 m s a u 6 n a m vd d ^ n C K 3 s a u 5 n a m cd s i n h t r u d n g c h i ^ c a o 19,2 m v u g t h d i r a t n h i e u s o v d i 2 c h u k ^ t r u d c d d . O e a 2 e h u k y s a u , e d c n g h i d m t h i i c d e l^ii V L H C S K T cd s i n h t r u d n g c h i ^ u e a o k h d c b i d t s o vdi d d i c h i i n g (Fl). K h i s o s a n h s i n h t r u d n g c h i ^ u c a o d C K 3 d c i m g n g h i d m tinic F m ( d e lai V L H C S K I ) v u g t h O i h o n s o v d i C K 2 Id 14%.
3.4. l Y u h i g n g r i m g q u a c d c c h u k ^ k i n h d o a n h T r i i l u g n g c u a rimg h o n g q u a c a c c h u 1 ^ k i n h d o a n h d u g c cai t h i d n m d t c d c h r d r e t k h i dp d t m g b i d n p h d p q u d n ly V L H C S K T , k i e m s o a t e d d a i b a n g t h u d c didt c d v a k h d n g ed t a c d d n g e a y x d i d d t d c a c c h u k y s a u . K e t q u a d d n h gid q u a 3 c h u 1 ^ k i n h d o a n h dtroc t h e h i d n d h i n h 4.
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 1/2015 131
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O cdc chu ky sau, giiia cdc nghidm thiie ed su khdc bidt rd rdt vd tru lugng ning, cao nhdt d nghiem thiic ITi sau dd d^n Fm vd thap nhat la nghidm thiic Fl. Khi de lai VLHCSKT d chu ky 2 da lam tang tili lugng rimg tir 151,9 mVha ldn 165,2 mVha va ti^p tiic duy til vide d^ lai VLHCSKT d chu ky 3 da lam tang tru lugng rung ldn 169,3 mVha khi rimg d tuoi 5. Vide de lai gap ddi lugng VLHCSKT eua chu ky 1 ldm tang tru lugng rimg tii 151,9 mVha ldn 180,4 mVha va khi ti^p tiic de lai VLHCSKT cua chu ky 2 cd bdn b6 sung thdm 300 g supe lan don/cay d CK3 da cho trii lirgng ning d tudi 5 Id 185,6 mVha. 6 ca 2 chu ky sau, khi de lai VLHCSKT thi tili lugng rimg trong keo Id trdm cd sir khac biet rd ret ve thdng kd d ca 3 nghidm thiic. Sau 5 nam rimg trong d CK3, nghidm tiiuc Fh cd tioi lugng eao nhdt (185,6 mVha) tang 9% so vdi Fm (169,3 mVha) va tang 19% so vdi Fl (155,4 mVha). Khi so sanh d nghiem thiie Fm thi CK3 vugt 2% so vdi CK2 cho du tuoi rimg thap hon.
Nhu vdy, hidu qua ciia vide de lai VLHCSKT da lam tang trii lugng ning tiong keo la ham qua eae chu ky kinh doanh.
3.5. Nang sudt rimg qua cdc chu k^ kinh doanh
Lugng tang trudng butti qudn hdng nam (MAI) (m^/ha/nam) ciia rimg trong keo la trdm qua cdc ehu ky kinh doanh khi giir lai VLHCSKT la khdc bidt rd rdt, dtrgc th^ hidn d hinh 5.
O chu ky 2 sau 6 nam giii lai VLHCSKT da lam tang MAI 2 - 5 mVha/nam so vdi ddi chiing va giiia cdc nghiem thiic cd s u khac bidt rat rd rdt vk thdng kd. O ehu kjr 3, cac nghidm tiiirc git^ lai VLHCSKT da ed MAI tang 3 - 6 mVha/nam d tudi 5, cu th^: i) Bb, Fm ed MAI fang ldn luot Id 19,5% vd 8,9% so vdi d6i chiing (Fl); ii) Fh dat eao nhdt 37,1 mVha/nam, Fm la 33,9 m^/ha/nam, cdn doi ehiing 31,1 m^/ha/nam Khi so sdnh nghidm thiic Fm khi d^ lai VLHCSKT 6 chu ky 3 thi nang suat ning vugt 23% so vdi CK2. 6 chu ky dau hong rimg san xudt thi nang suat thap dat 18,6 mVha/nam, den chu ky 2 khi d^ lai gap doi VLHCSKT da nang nang sudt rimg len 30,1 mVha/nam va ddn ehu ky 3 khi d^ lgi VLHCSKT va bdn b6 stmg 300 g supe lan don/cdy da cho nang sudt riing d tudi 5 dat 37,1 m^/ha/ndm, tuong dtrong vdi rimg hong Keo lai tham canh hdn ldp dia tot nhat d Vidt Nam. So lidu nay cho thay, hem nang pMt tri^n keo la ham d vimg Ddng Nam bd bang ede l^
thuat giii lai VLHCSKT se dem Iai hidu qua kinh te cao cho ngudi hong rtmg.
3.6. Sinh kh6i rimg
K^t qua nghidn eiiu smh khdi rimg hong keo Id hdm qua 3 chu k^ kuih doanh khi giti lai VLHCSKT d cdc chu ky sau da cd tde ddng ldn den sinh khoi khd cua ning Qiinh 6).
Bico iKng MAI (m^/ha/nam) caa 3 nghiem Ihuc theo tu6i m n g qua 3chulLy kinh doanh
O i l CKI H m h 5. B i & dOng lugng t a n g h u d n g b i n h qudn n a m H i n h 6^ B i ^ dOng t 6 n g 7 i n h k h d i k h d
Blen doQg loBg sinh kh^ kh6 (tSn/ha) cda cdc nghifin thik qua3 chukykiQh doanb riing Irong keo la IrSm
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KHOA HOC CONG NGHE Nhu vay, sinh khdi rimg trdng keo la trdm d ehu
k^ 2 va 3 khi giu lai VLHCSKT da vugt hdi so vdi chu ky kinh doanh dau. 6 CK2 de lai VLHCSKT sau 6 nam da ldm tang sinh khdi rimg khoang 9% va gap ddi lugng VLHCSKT sau 6 nam da lam tang 18,5% so vdi ddi chung (lay di VLHCSKT). O CK3 de lai VLHCSKT (Fm) sau 5 nam da ldm tang 6,7% sinh khdi vd d^ lgi VLHCSKT cd bdn bo sung 300 g supe ldn don/cay (Fh) tang 16,7% so vdi edng thiie ddi chirng Fl Oay di VLHCSKT). Tong sinh khdi khd cua nghidm thiic Fh Id eao nhat, sau dd d^n Fm va thap nhat Id Fl vd giiia cdc nghidm thuc cd su khde bidt rdt rd rdt d tdt ed ede tudi rimg. Qua 11 nam ap dung quan ly lap dia bang bidn phdp d& lai ATJICSKT da ed mdt ngudn dinh dudng dang ke tra 1^ cho ddt tii nguon VLHCSKT, tdng cay bui tham tuoi dudi tan ning va lirgng vat rung hdng nam da giiip cai thien dd phi cua ddt d ede ehu ky sau (Ki^u Tuan Dat va es, 2014). T6ng sinh khdi khd cua nghidm ttiiic Fm sau 11 nam giti lai VLHCSKT hrong duong so vdi CK2 (rimg 6 nam tuoi) va vugt 153% so vdi CKI (rimg 7 nam tuoi).
4.KnLIMlN
Giii lai VliiCSKT da gdp phdn lam tang ty le song cua rimg hdng keo la ham qua cdc chu ky kinh doanh. Sinh trudng eay qua cac chu ky ngdy cdng dugc cai thidn: i) ehieu cao d CK3 cua nghidm thiie Fh la tot nhdt, ed Hvn = 19,2 m, vugt hOi 16% so vdi CK2; ii) dudng kinh d 2 chu ky sau khi de lai VLHCSKT d^u ed smh trudng eao hon so vdi nghidm ttiiic ldy di todn bd VLHCSKT.
Sau 11 nam (6 nam CK2 va 5 nam CK3) giii lai VLHCSKT da gdp phdn tang trii lugng rimg d edc chu ky sau. O CK3 trii lugng ning da tang 11% so vdi CK2 vd 41% so vdi CKI mac du tudi rung thap hon.
Sau 5 nam tru lugng riing trong d CK3 cua nghidm thiic Fh Id tot nhat, dat 185,6 m^/ha, tuong dtrong MAI = 37,1 mVha/nam vugt ti-di so vdi CK2 (30,1 mVha/nam) vd CKI chi ed 18,6 m^/ha/nam. Ddy la mdt birdc cai thidn rat ldn ve nang sudt rimg khi nd dang ed xu the gidm sau ede chu ky kinh doanh.
Sinh khoi khd hen mat ddt ciia ning hong keo la tram b CK3 tang 10% so vdi ehu ky 2 va tang 179% so
vdi ehu ky 1 mac dii tuoi rung thap hon. O CK3 nghidm tiuic Fh dat 142,8 tdn/ha, vugt 10,2% so vdi Fm (129,5 tdn/ha) va vugt 17,6% so vdi nghiem ttiiie ddi chimg Fl (121,5 tdn/ha).
Nhu vay vide de lai vat lieu hiiu eo sau khai thac rimg da lam tang nang suat cua ning khoang 3 mVha/nam. D^ lai VLHCSKT va bdn bd sung ttidm 300 g supe lan don (16,5% P205)/cay eho nang sudt rimg tang khoang 3 m^/ha/nam so vdi ddi chiing ady di todn bd VLHCSKT) •
TAI lEi nUM WHO
1. Kieu Tuan Dat, Pham The Dung, Ld Thanh Quang, 2014. Xic dmh cic ngudn dinh duong cd kha nang cung dp cho dit trong tidng ning keo li tiim (Aauriculiformis) dPhii Binh, Binh Duang. Tap chi Khoa hgc Ldm nghidp, s6 3/2014, hang 3469 - 3475.
2. Pham Lh^ DOng, Kieu Tuan Dat, Vu Dinh Hudng, Ld Thanh Quang, Pham Van Bdn. Quin ly vat heu sau khai thic rimg nhim ning cao do phi da't vi ning suit rimg tidng keo li tiim luin ky sau. Bdo cao tdng ket de tdi trgng di^m cap Bg, nam 2012.
3. Pham Th^ Dung, Kieu Tudn Dat, 2014.
Nghidn ciiu quin l^lip dia nhim ning cao nang suit ning tiong keo li trim (A. auriculiformis) tai tinh Binh Duong. Tap chi Ndng nghidp vd Phat tri^n Ndng tiidn, s6 7 nam -2014, hang 97 -102.
4. Nambiar E. K S. and C. E. Harwood, 2014.
Productivity of acacia and eucalypt plantations in South-East Asia. 1. Bio-physical determinants of production: opportunities and challenges.
International Forestiy Review. Vol.16 (1), 2014.
5. Vu Dinh Huong, Le Thanh Quang, Nguyen Thanh Bmh, Pham The Dung, 2008. Site management and productivity of Acacia auriculiformis Plantations in South Vietnam. In:
Nambiar, E. K. S. (ed.): Site management and productivity in tropical plantation fores. Workshop proceedmgs, 22-26 November 2004 Phacicaba, Brazil, and 6-9 November, Borgor, Indonesia, 123- 138. Center for International Forest Research, Bogor, Indonesia.
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 1/2015 133
KHOA HOC CdNG NGHE
THE EFFECT OF SLASH RETENTION TO INCREASE P R O D U C n v n Y OF A auricw •*' PLANTATION AFTER PRODUCTION ROTATIONS IN PHU BINH, BINH DUONG PROV i'JCE
Kieu Tuan Dat, Pham ^ 'uiig Summary
The tendency on decrease of plantation yield after business rotadon becomes an issue which should be solved for forest sustainable development in Vietnam. This study conducted to appreciate tbe effective of retention of organic residue after plantabon harvesting on growth, yield and dry biomass of AauricuUformis plantation during tiuee rotation in Phu Bmh, Binh Duong province. They are production forest in first rotation - CKI (199&-2002), experimental forest in second rotation- CK2 (2002-2008) and experimental forest in tiiird rotation - CK3 (2008-2013). The experimental design was a randomized complete block with three treatments and five replications. Treataients are : i) Fl - all aboveground organic master including tbe crop tree, understory, slash and Utter of CKI & CK2 is removed; li) Fm - stem wood +bark harvested. Stand is felled and tops and branches are cut and retained in the treatment's plot and all other organic residue of CKI
& CK2 is left; iii) Fh - double slash of CKI and retained residue of CK2 and added 300 g of fertilizer single super phosphate (16.5% Yp^/ti^ (equivalent 36 kg P/ha). Planted density is 1,667 stocks/ha.
Experimental result pointed: the retention of organic residue is to increase survival rate of tree and tbe growth, yield, dry biomass of Aauriculiformis plantation. In CK3 with 5 years old plantation, tbe wood volume of Fh treatment is maximum by 185.6 m^Aa and over 2.8% to compare with 180.4 m^/ba in CK2 - older one year. Mean annually mcreasing (MAD in C¥3, is 37.1 m'/ha/year to compare with 30.1 m^/ha/year in CK2 that is an important step to improve plantation productivity. The dry biomass of plantation m CK3 and CK2 is equal while plantation of CK2 older CK3 1 year. In CK3, dry biomass of Fh is 142.8 ton/ha and over 10.2% & 17.6% to compare with Fm (129.5 ton/ha) and Fl (121.5 ton/ha), respectively.
By this way, the retention of organic residue contributed to improve a soil fertility and increase a productivity of AauncuM»m/s plantation on gray- alluvial soil in Binh Duong province.
Ifey word: Slash retention, growth, productivity, biomass.
Ngudi phdn bidn: TS. Dd Anh TuSn Ngdy n h ^ bdi: 10/11/2014 Ngdy tiidng qua phdn bidn: 12/12/2014 Ngdy duydt dang: 19/12/2014
