KHOA HOC C O N G N G H E
K E T Q U A IMGHIEIM C l i U BOIM PHAIM CHO RIJIMG TROIMG K E O T A I TUqiMG [Acacia mangiuni[ CUIMG C A P
G 6 L Q I M O Q U A I M G I M I I M H
VQ Ti^n Lam^ Nguyen Huy Son^
Pham Dinh Sam^ Hd Trung Luong^
TOMTAT
Keo tai tuong (Acacia mangium) la cay trdng lam nghiep chii luc a nuoc ta hien nay, de nang cao nang suat gd rung trong, mot trong nhung bien phap ky thuat quan trong la bon phan cho rirng trong. Tuy nhien, can phai can cii vao dac diem dat de xac dinh loai phan va lieu luong phan bon cho phu hop nhdm dat duoc muc dich chiing ta mong mudn. Dat a khu vuc thi nghiem co do pHuci ~ 3,57-3,73, ham luong miin 1,10 - 2.53%, ham lugng ni to tdng sd (Nts) 0,063 - 0,155%; ham lirong P.O5 d6 tieu thap duoi 3 mg/100 g dat, ham luong K2O dh tieu 6,6 - 17,4 mg/100 g dat. Sau 1 nam trong voi 5 cong thiic bon lot khac nhau, ty le sdng trung binh cua Keo tai tuong dat 92,59%, dirong kinh trung binh (Dj 3) dat 2,79 cm, chi^u cao trung binh (Hvn) dat 1,89 m, duong kinh tan trung binh (Dt) dat 1,22 m; tdt nhat a cong thiic bon 500 g NPK (16:16:8) voi duong kinh ngang nguc dat 3,47 cm, chifeu cao 2,11 ra, dirtmg kinh tan dat 1,42 m; k^m nhat 6 cac cOng thiic khong bon phan voi cac gia tri tuong irng la 2,34 cm; 1,73 m va 1,17 m. Sau 2 nam tudi, tiic la sau 1 nam bon thuc vol 9 cong thiic khac nhau, ty 1^ sdng trung binh cua Keo tai tugng toan thi nghiem dat 88,72%, duong kinh trung binh toan dat 7,58 cm, chieu cao trung binh dat 6,56 m, duong kinh tan trung binh dat 4,38 m. Giua cac cong thuc bon phan da co su khac nhau kha ro ret. cac cong thirc bon ian (P-fl^) tot hon han so voi cong thuc chi bon NPK (16:16:8), trong do tOt nhdt a cong thiic bon 0,4 kg PaOs/gdc voi duong kinh dat 8.43 cm, chieu cao dat 6,81 m; kem nhat o cong thiic khong bon phan lam ddi chiing chung voi cac tri sd tuong iing la 6,77 cm va 6,20 m.
Tii khda; Bon phan, Keo tai tuong, sinh trudng, tinh Quang Nmh.
1 . BAT VAN BE
Keo tai tugng (Acacia mangium) la mot trong nhiing loai cay trdng chu luc d nude ta trong nhidu nam vira qua va hien nay. La cay sinh trudng nhanh, nang suat gd cao, go cd dac diem phu hgp vdi cong nghe che bien cac san pham npi that sir dung trong nuoc vd xudt khau. Dien tich rimg trdng sdn xuat d- nude ta hien nay co khoang tren 2,9 trieu ha (Bp Nong nghiep va PTNT, 2018), it nhat cd khoang 50%
dien tich Id rimg trong cdc loai keo, trong dd phan Idn la Keo tai tuong. Theo de an tai co cau ngdnh lam nghiep (Bd Nong nghiep va PTNT, 2013) cdn phdi trdng mdi khoang 1,0 trieu ha va 0,35 trieu ha cai tao rimg tu nhien ngheo kiet, dac biet la phdi qui hoach viing ti-dng rimg tap trung cung cap gd lon cho che bien khoang 1,2 trieu ha, trong dd uu tien cac loai cay moc nhanh cung cap gd lon. De nang cao nang suat gd rimg trdng cao hon nira, dac biet la nang suat rimg (rdng kinh doanh gd Idn Keo tai tirong vdi chu
ky kinh doanh tren 10 nam, cdn thiet phai ap dung he thdng cac bien phap ky thuat tham canh rimg. Trong dd, bdn phan cho rimg trdng la mot trong nhimg bien phap ky thuat quan trgng chinh ciia trdng rimg tham canh va tham canh rimg trdng (Nguydn Huy Son va cong su, 2006). Duoi day xin gidi thieu ket qua budc dau v^ co so khoa hgc bdn phan cho Keo tai tuong d giai doan 2 nam tudi trdng b Uong Bi (Quang Ninh).
Z. VAT UEU VA PHUONG PHAP NGHIEN CUU 2.1. Vdt li^u nghidn ciru
Gidng Keo tai tuong gdm 4 xuat xii: BV.48.02 {Vudn gidng Bau Bang); Oriomo; Ham Yen va Vudn gidng BaVi, trdng hdn hop theo tyle 1:1:1:1. Cay con cd bdu dugc gieo uom tir hat; tieu chuan cay con khi trdng 3 - 4 tiiang tijoi, dudng kinh cd rk (Doo) 0,4 cm - 0,6 cm, chieu cao 25 cm - 30 cm. Mat do trdng ban dau la 1.100 cay/ha (3x3m). Phan bdn gdm NPK (16:16:8), phan hiru ca vi sinh (VS), che pham sinh hgc (MFl), P2O5 (16,5%) va K p (60%).
' Vien Nghien cuu Lam sinh
^ Trung tam Nghidn cuu Lam san ngoai go
KHOA HOC C O N G N G H E
2.1.1. Phuongphip dieu tra thu thap sdheu dat Loai dat va da me xac dinh theo phuang phap chuyen gia. Hdng nam trudc khi quyet dinh Ueu lugng vd loai phan bdn tien hanh dao 3 phdu dien, d cac vi tri chan, sudn vd dinh ddi moi phdu dien lay 3 mdu dat vd dung trgng d cdc tdng: 0 - 20 cm, 30 - 50 cm vd 80 -100 cm (mdi man dat dugc ti-gn deu tu cac phau dien va lay 0,5 kg de di phan tich). Cdc chi beu ly hda tinh ddt phan tich theo cac tieu chuan Qudc gia tai Vien Nghien ciiu Sinh thai va Moi trudng rimg (Vien Khoa hgc Lam nghiep Viet Nam), gdm: Dung trgng theo tieu chuan TCVN 6860: 2001; pH^ci tiieo TCVN 5979: 2007; him ca tong sd theo TCVN 4050 - 85; dam tdng sd (Nts) theo TCVN 6498: 1999; PgOg d§ tieu tiieo TCVN 5256: 2009; K2O dd tieu theo TCVN 8662: 2011; CEC theo TCVN 6646: 2000; thdnh phdn CO giai theo TCVN 5257:1990.
2.1.2. Phuang phap thu thap va phan tich miu li Sau 1 nam trdng vdi 5 cong thirc bdn phan, lap lai 3 lan, mdu Id dugc thu thap tdng cong la 15 mdu.
Sau khi do thu thap sd lieu dmh ky khi cay dat 12 thdng tuoi xir ly so lieu tien hanh chon 01 cay cd chi sd trung binh ve D13, Hvn va Dt cua moi cong thirc thi nghiem rdi tien hdnh thu moi cay 20 la banh te d giira tdn de phan tich, tong sd cd 15 mau la dai dien cho 5 cong thiic bdn Idt va duoc lap lai 3 lan. Tuong tu nhu thd de thuc hien lay mdu la truoc khi bon thiic cho cac nam tiep theo. Chi tieu phan tich gdm: Ni to tdng sd (Nts) phan tich theo tieu chuan 10 TCN 451:
2001; lan tong so (Pts) theo tieu chuan 10 TCN 453:
2001; kali tdng sd (Kts) theo tieu chuan 10 TCN 454:
2001.
2.1.3. Phuongphap bd tii thi nghiem - Bdn lot Thi nghiem bdn lot dugc bd tri theo khdi ngau nhien lap lai 3 lan, gdm 5 cong thiic sau day: CTl. Bdn 1.000 g Vi sinh Song Gianh/hd (VS);
CT2. Bdn 500 g NPK/hd; CT3. Bdn 1.000 g VS Song Gianh -H 500 g NPK/hd; CT4. Bdn 50 g che pham vi sinh MFl/hd; CT5. Khong bdn phan (ddi chiing chung - DC).
- Bon thic. Tren co sd thi nghiem bdn Idt, sau khi phan tich ham lugng N, P, K trong la Keo tai tugng 1 nam tudi, xac dinh trong dat thieu lan so vdi nhu cdu cua cay; tir cac cong thirc thi nghiem (8 cay X 8 hang tdng la 64 cay/1 6 thi nghiem da trir di hang bao quanh) b cac cong thiic bdn Idt, mdi 6 thi nghiem dupe chia lam 2 phdn mdi cong thiic 32 cay
(neng cong thiic ddi chiing khong chia vd khong bdn thiic de lam ddi chiing chung), mot phan bdn thiic 200 g NPK/gdc a>dn thiic nhu b-ong san xudt dai tra), phdn con lai bdn tiuic P2O5 (16,5%) va K2O (60%) vdi cac Udu lugng khac nhau (g/gdc) theo 9 cong thirc sau day:
CTl.l. Bdn tiuic 100 g K2O -H 200 gPaOs;
CT1.2. Bdn tiiuc 200 g NPK ^ C l ) ; CT2.1. Bdn tiuic 100 g K^O + 400 gPaOs;
CT2.2. Bdn thiic 200 g NPK (DC2);
CT3.1. Bdn thuc 100 g K^O + 600 gPaOj;
CT3.2. Bdn tiuic 200 g NPK (DC3);
Cr4.1. Bdn thuc 100 g K^O + 800 gPaO^;
CT4.2. Bon tiiiic 200 g NPK (DC4);
(Jr5. Khong bon phan (ddi chiing chung-DC).
2.1.4. Phuongphap thu thap va xuly sdh'eu - Thu thap sd Ueu theo phuong phap dieu tra 6 tieu chuan dinh vi, dung lugng mdu 32 cay/cong thiic thi nghiem. Chi tieu do dem gdm: ty Id sdng (TLS) theo phuong phap thdng ke; dudng kinh ngang nguc (D13) do bdng thuoc palme cd dd chinh xac tdi 0,1 mm; chidu cao viit ngon (Hvn) do bang thuoc do cao Vtec cd d6 chinh xac tdi 0,1 m; dudng kinh tdn (Dt) do bang thude day theo hinh chieu tan (hinh chieu diing cua tan la cay) tren mat ddt.
- Xu ly sd lieu theo phuong phap thdng ke toan hgc ling dung cac phan mdm chuyen dung tren may tinh nhu: Excel, SPSS (Nguydn Hai Tuat va cong su, 2006).
3 . KET QUA NGHEN GUU VA THAO LUJUU
3.1. Dac dilm dat vd dd m? noi bd tri thi nghi§m Dia diem xay dung mo hinh thi nghifim la dat cua Trudng Cao ddng Nong Lam Dong Bdc quan ly, thugc dia ban phuong Bdc Son, thanh phd Uong Bi, tinh Quang Ninh. Khu vuc bd tri cac thi nghiem chii yeu la dat feralit phdt trien tren da put dinh, thugc nhdm da bien chat. Thuc bi chu yeu: Tham tuoi: co la tre, cd Idt, cd tranh va duong xi; cay bui: Sim, mua, sdm, cao trung binh duoi 7 m, dp che phu 60 - 70%, la hien trudng trdng rimg Thong nhua ghep khdng thdnh cong tir truoc nam 2010, nen co the xem day la mot dang dat moi ddi voi Keo tai tugng. Ket qua phan tich mot sd tinh chat vat ly ddt (Bang 1) cho tiiay dung trgng ddt, tdng A do sau 0 - 20 cm dao dong 0,987-1,006 g/cm^ tang B do sau 30 - 50 cm dao dong
KHOA HOC CONG NGHE
1,124 - 1,275 g/aa', ting C do sau 80 - 100 cm dao pMu dien chiem ty 1ft kha cao, kha nang gift niroc dong 1,195-1,489 g/cml Mat khac, ham lucmg set va kha tdt, phii hop cac loai keo noi chung va Keo tai set vat ly (cap hat < 0,02 mm) o tang mat cua cac tuong noi rieng (Hung, 2016).
Bang 1. Bac di^m vgt ly ciia dat noi thi nghigm KihiftuPD
Mtt20 (chan) Mtt21 (suon) Mtt22 (gki dinh)
Do sau (cm) 0-20 30-50 80-100 0-20 30-50 80-100 0-20 30-50 80-100
Dung trong (g/cm=)
0,987 1,124 1,485 1,007 1,125 1,489 1.066 1,275 1,195
<0,002 (mm) 30,96 39,30 37,08 31,46 37,10 36,05 26,89 30,96 48,07
0,002-0,02 (nim) 24,77 22,75 24,72 25,20 25,79 24,74 24,82 22,70 16,72
0,02-2,0 (mm) 44,27 37,95 38,21 44,34 38,91 39,21 48,29 46,34 35,21 Ket qua phan tich tinh chat hda hoc cua dat
(Bang 2) cho thay dat cd phdn iing rat chua vdi do PHKCI ~ 3,57 - 3,73. Hau het cdc phdu dien deu co ham lugng mim cua tdng mat d miic trung binh. Cu the, tang mat 0 - 20 cm cd ham luong miin a miic trung binh (2,37 - 2,53%), tdng 30 - 50 cm d' miic ngheo (1,29-1,31%) va tdng 80 -100 cm b can dudi ctia
Bang 2. B&cdiim hda hgc ciia ddt noi thi nghiem
miic ngheo (1,06 - 1,15%). Tuong tu nhu vay, ham lugng ni to tdng sd (Nts) phan lon d mirc trung binh, tang mat (0 - 20 cm) cua cac phdu dien Nts dao dong 0,127 - 0,155%, tdng 30 - 50 cm chi cdn 0,068 - 0,123%, tdng 80 -100 cm chi con 0,063 - 0,105% (Cam nang nganh lam nghiep, 2006).
Ki hiftu PD Mtt20 (chan) Mtt21 (suon) Mtt22 (gan dinh)
D6 sau (cm)
0-20 30-50 80-100
0-20 30-50 80-100
0-20 20-50 80-100
PHKCI 3,57 3,70 3,73 3,61 3,71 3,72 3,65 3,70 3,72
Miin
(%)
2,53 1,31 1,15 2,50 1,29 1,10 2,37 1,31 1,06
Nts
(%)
0,155 0,123 0,100 0,152 0,117 0,105 0,127 0,068 0,063
(mg/kg) 16,96 15,26 5,70 16,90 15,27 5,45 30,85 16,14 6,37
KjO (mg/kg)
174,41 151,65 95,74 104,39 132,61 75,34 94,77 85,18 66,11
CEC (Ldl/100)
15,89 12,31 24,46 15,59 12,97 23,26 18,87 14,09 22,87 Ham luong P2O5 dft tieu o miic rat ngheo <3
rag/100 g dat (<30 mg/1 kg dat). Ham luong KjO dft heu dao dpng 6,6 -17,4 mg/100 g dat va giam dan tu tang mat xuong t ^ g duoi. Dat khu vuc nghien cuu CO ham luong K2O o muc tu ngheo den trung binh.
Tii ket qua phan dch cac mSu dat lai bang 1 va 2 CO th^ thay dat o khu vuc nghiftn kha chua, ham luong miin va dam a miic trung binh, kaU o miic ngheo den trung binh, nhung lan a miic rat nghfto, dac biet la ham luong lan de heu rat ngheo, ket qua nay cung rat phii hop voi nhan dinh cua Sunpson, J. A., (2000) khi nghiftn ciru dac diem dat trong Keo tai tuong o Trung Quoc va Kalimantan. Vi vay, khi trong rimg
can phai tang cuimg loai phan co ham lugng P2O5 cao.
3.2. Anh huong cua phan b6n Idt dfo sinh tnrong oia Keo tai taong sau 1 nSm trong
Voi dac di^m dat nhu da trinh bay cr tren, thi nghiem bon lot phan cho Keo tai tuong khi trftng gom 5 cong thirc (Bang 3), sau 12 thang tudi voi cac cdng thuc thi nghiem bdn lot khac nhau, ty le sdng trung binh cua cac cong thirc thi nghiem dat kha cao, trung binh toan thi nghiem dat 92,59%, dao ddng 81,48-100%, cao nhat d cdng thirc CT3 va CT4 (100%), thap nhat a cdng thiic CT2 (81,48%).
KHOA HOC CONG NGHl
Bang 3. Sinh trudng ciia Cdng thiic thi nghiem
(CTTN) CTl: 1,0 kg VS CT2:0,5kgNPK CT3:0,5kgNPK + l,0kgVS CT4: 0,05 kg MFl CT5: Khdng bdn (DC)
Trung bmh Sig.F (0,05)
TLS
(%)
86,11 81,48 100,0 100,0 95,37 92,59
Keo tai tuong 12 thang tu6i (6/2016 - 6/2017) Dudng kinh
D,,3 (cm) 2,68 2,96 3,47 2,50 2,34 2,79
Sd(%) 42,79 43,74 33,77 33,51 35,98 37,96 0,000
Chieu cao Hvn (m)
1,83 2,00 2,11 1,79 1,73 1,89
Sh(%) 28,48 28,05 22,28 26,01 24,31 25,83 0,000
Budng kinh tan Dt (cm)
1,14 1,22 1,42 1,14 ^ 1,17 1,22
Sdt (%) 30,14 34,50 28,55 29,99 24,08 30,64 0,000 Kha nang smh trudng cua Keo tai tugng giira cac
cong thiic thi nghiSm giai doan 1 nam tuoi kha nhanh ke ca cong thiic khong bdn phan lam ddi chiing. Tuy nhien, ket qua phan tich phuong sai cho thdy giira cac cong thiic thi nghiem bdn Idt phan da khde nhau kha rd ret ca dudng kinh ngang nguc, chidu cao vut ngon va dudng kinh tan (Sig.F < 0,05).
Dudng kinh ngang nguc (D13) trung binh toan thi nghiem dat 2,73 cm, dao dong giira cdc cong thitc thi nghiem 2,34 - 3,17 cm, tdt nhat d cong thuc bdn lot 0,5 kg NPK ket hgp 1,0 kg phan hiru co vi sinh (CT3), thap nhat d cong thiic khong bdn phan lam ddi chimg (CT5). Chieu cao trung binh toan thi nghiem (Hvn) dat 1,89 m, giua cac c6ng thirc thi nghiem dao dong 1,73 - 2,11 m, sinh trudng tdt nhat vdn d cong thiic bon lot 0,5 kg NPK ket hgp 1,0 kg phan hiru co vi sinh (CT3), thap nhat d cong thirc khong bdn phan 1dm ddi chiing (Crr5). Sinh trudng dudng kinh tdn trung binh toan thi nghiSm (Dt) cung dat 1,22 m, dao dong 1,14 - 1,42 m, dudng kinh tan Bang 4. Hdm lugng N, P, K trong
Idn nhat vdn d cac cong thirc CT3 (1,42 m), nhd nhat Id d cac cong thirc CTl va CT4 (1,14 m). He sd bi^n dong cua dudng kinh (Sd) trung binh toan thi nghiem la 37,96%, he so bien dong chieu cao (Sh) trung binh toan thi nghiem la 25,83%, he sd bien dong cua dudng kinh tdn (Sdt) trung binh toan thi nghidm la 30,64% (Bang 3). Didu ddng chii y la d cac cdng thiic bdn 0,5 kg NPK thi kha nang sinh trudng cua Keo tai tugng deu tdt hon cac cong thiic khac.
Didu nay cd the ly gidi rang tuy Keo tai tuong cd kha nang cd dinh dam sinh hgc, nhung cay con mdi trdng tren dat mdi vdn can phdi cd mot lugng ni to dd tieu
(Ndt) nhdt dinh giup cho su cong sinh giua vi khuan cd dinh dam vdi hd rd cam cua cay de hinh thdnh ndt sdn cd dinh dam dugc nhanh hon. Ket qua nay cQng rat phu hop vdi ket qua nghien ciiu bdn phan cho rimg trdng Keo lai d Quang Ninh ciia Nguyin Huy Son va cong su (2018).
3.3. K^t qud phan tich N, P, K tdng s6 troBg Id Keo tai tijgng sau 1 nam tuoi
cdc mdu la Keo tai tugng 1 nam tudi SdTT
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
-
BP BP BP BP BP BP BP BP BP BP BP BP BP
K T F - m P J K KTr-R3P5T5 KTr-R2PlT3 KTr-R3P4T3 KTr-RlPlT2 Krr-R2P2T4 KTr-R2P5T5 KIT-R2P4T1 KTT-R3P1T2 KTT-R1P2T3 KTT-R3P3T1 KTT-R3P3T4 KrT-RlP3T5 BP-KTT-R1P4T4 BP-KTT-R1P5T2
Tdng sd (%) N
1,447 1,336 1,661 2,612 2,239 1,152 1,643 1,589 2,437 1,762 1,157 1,578 1,699 2,025 1,621
P , 0 , 0,531 0,359 0,509 0,408 0,431 0,512 0,624 0,292 0,575 0,447 0.300 0,270 0,352 0,388 0,447
K,0 0,193 0,205 0,217 0,217 0,229 0,121 0,253 0,253 0,229 0,217 0,108 0,193 0,265 0,217 0,157
KHOA HOC CONG NGHl Phan tich ham lugng cdc nguyen td da lugng (N,
P, K) trong la cay Keo tai tugng sau nam thir nhat, k^t hgp sd heu phan tich dat dd lam ca sd xac dinh nhu cdu phan bdn thuc cho nam thir hai.
Ket qud phan tich 15 mdu la cua Keo tai tuong sau 1 nam tuoi d cac cong thiic bdn lot phan khde nhau (Bang 4), so sanh vdi ket qua phan tich thanh phan hda hgc dat (Bdng 2) cho thay ham luong ni to tdng sd (Nts) trong la cao hon nhieu so vdi ham lugng Nts trong dat, cao nhdt d ldp dat mat (0 - 20 cm) Cling chi cd 0,127 - 0,155%, nhung trong la cd 1,152 - 2,612%; dieu do chiing td nhu cdu sir dung N kha Idn, mot phan N do ddt cung cap, phdn Idn la do cay cd kha nang cd dinh dam sinh hgc thong qua he thong ndt sdn dugc cung cap bd sung, nen ham lugng N trong Id rat cao va da dap iing duoc nhu cau ve N cho cay. Dac biet, ham lugng P2O5 tdng sd trong Id cay lon hon nhiSu so vdd d trong ddt, ham luong P2O5 de tieu d ldp dat mat cao nhdt cung chi 16,90 - 30,85 mg/kg dat, tuong duong vdi 1,690 - 3,085 mg/100 g dat, nhung trong la cua Keo tai tugng cao hon khoang 1,5-2 Idn so voi d trong dat, dieu nay co the thay nhu cdu vd P2O5 cua Keo tai
tugng khd Idn md trong ddt lai rat thieu. Ngugc lai, ham lugng K ^ trong la rat thdp, cdn thap ban ca d trong dat, mac du ham lugng KjO cua dat d miic ngheo, cao nhdt d ldp ddt mat cimg chi dao dong 94,77 - 174,41 mg/kg dat, tuong duong 9,477-17,441 g/100 g ddt, trong khi ham lugng K2O trong la dao dong 0,108 - 0,265%, tuong duong 1,08 - 2,65 mg/100 g Id, dieu nay cho thdy nhu cdu ve K2O khong Idn ddi vdi Keo tai tugng. Nhu vay, day ciing la co sd khoa hoc cdn thiet phai bdn bo sung P2O5 cho Keo tai tuong b cac giai doan tuoi khac nhau.
3.4. Anh huong cua bdn thiic P2O5 d^n sinh tnrong cua Keo tai tugng 2 nam tudi
Tir ket qua phan tich dat ban ddu va ket qua phan tich man la cho thay nhu cdu dinh duong trong la can lan hon la dam va kali. Vi vay, nam thir hai da dieu chinh phan bdn thuc tang ham lugng P^f)^ b mot sd cong thiic (Bang 5), sau 2 nam trdng, tiic la sau 1 nam bon thuc, ty le sdng trung binh toan thi nghiem tuy cd giam so vdi nam thir nhat khodng 4%, nhung vdn cdn 88,72%, dao dong giira cac cong thiic 80,65 - 98,36%, chu ydu la do gay do gio bao.
Ky hieu CTTN CTl.l CT1.2 CT2.1 CT2.2 CT3.1 CT3.2 CT4.1 CT4.2 CT5
Bang 5. Sinh tnidng cua Keo tai tmmg 24 thang tudi (6/2016-6/2018) Ndi dung CTTN
bdn thiic phan 0,1 kg K,0 -I- 0,2 kg P,0^
0,2 kg NPK (DCl) 0,lkgKzO-i-0,4kgP,Os 0,2kgNPK(DC2) ClkgKjO+O.OkgP^Os 0,2 kg NPK (DC3) 0,lkgK2O+0,8kgPi,Os 0,2 kg NPK (DC4) Khdng bdn (DC)
SigF
TLS
(%)
84,44 83,33 85,00 90,04 98,36 80,65 93,33 90,00 93,33 88,72
Dudng kinh D,,3 (cm) 7,09 6,94 8,43 8,21 8,11 7,68 7,92 7,10 6,77 7,58
Sd(%) 24,07 22,52 21,82 25,78 20,95 27,29 23,23 27,08 23,40 24,01 0,000
Chidu cao Hvn (m) 6,53 6,30 6,81 6,64 6,75 6,42 6,78 6,64 6,20 6,56
Sh
(%)
10,91 9,02 8,88 13.00 8,32 15.47 10,71 9,83 12,25 10,93 0,000
Dudng kinh tan Dt (cm)
4,08 4,01 4,78 4,49 4,84 4,12 4,75 4,48 3,84 4,38
Sdt
(%)
18,59 13,06 16,30 21,44 18,32 20,34 16,83 19,94 22,09 18,55 0,000 Sau 2 nam tudi, dudng kinh ngang nguc trung
binh (Di^s) toan thi nghiem da dat 7,58 cm, tang trudng binh quan (Ad) dat 3,79 cm/nam; sinh trudng chieu cao viit ngon trung binh (Hvn) toan thi nghiem cung dat 6,56 m, tang tiirdng trung binh (Ah) toan thi nghiem dat 3,28 m/nam. Thong qua lugng tang trudng binh quan cua ca dudng kinh (Ad) va chieu cao (Ah) trong 2 nam dau cho thay kha nang sinh
trudng cua Keo tai tuong kha nhanh, nhat la khd nang sinh trudng d nam tini hai khong thua kem so vol Keo lai d mot sd mo hinh trong trong khu vuc.
Ket qud phan tich phuong sai cho thay ca dudng kinh vd chidu cao vut ngon trung binh giira cac cong thu'c thi nghiem da khac nhau khd ro ret (Sig F < 0,05), sinh trudng cao nhat b cong thiic bdn tiiiic 0,1 kg K2O + 0,4 kg P2O5 (CT2.1) vdi dudng kinh (Di,:t) dat
105
KHOA HQC CONG N G H l
8,43 cm va chieu cao dat 6,81 m, thdp nhat d cong thiic ddi chiing (CTTS) chi vdi cac tri sd tuong irng ve dudng kinh va chieu cao la 6,77 cm va 6,20 m. Neu so sdnh timg cap mot each tuong ddi giua cac cong thiic bdn thuc P2O5 va K2O vdi cac cong thirc chi bdn NPK thi cac cong thiic bdn P2O5 vd K2O cd khd nang sinh trudng cd dudng kinh va chieu cao luon luon cao hon ddng ke. Dieu nay chiing td bdn bd sung lan da cd tac dung khd ro ret ddi vdi khd nang sinh trudng cua Keo tai tugng, ket qua ndy hoan toan phii hop vdi nhan dinh ban ddu ve su thieu hut lan cua dat, dong thdi cung hodn toan phii hgp vdi nhan dinh cua Simpson, J. A. (2000) khi nghien cim vd dac diem dat cua rimg trdng Keo tai tugng d AustraUa. Mat khde, he sd bien dong cua cd dudng kinh (Sd) va chieu cao (Sh) da gidm nhieu so vdi nam thii nhdt, tuy nhiSn he sd bidn ddng trung binh ciia dudng kinh van cdn cao la 24,01%, nhung he sd bidn dong cua chieu cao da gidm rat manh chi cdn 10,93%. Dieu nay chiing td rdng khd nang sinh trudng ca dudng kinh va chidu cao cua cac ca the trong qudn thd da ddng deu hon so vdi nam thir nhat.
Ngoai ra, dudng kinh tan (Dt) trung binh toan thi nghiem giai doan 2 nam tuoi da dat 4,38 m, ket qua phan tich phuang sai cung cho thay khd nang sinh trudng ciia dudng kinh tan (Dt) giiia cac cong thirc thi nghiSm bdn phan cung khac nhau khd ro ret (Sig.F<0,05), cao nhdt d cong thiic CTS.l dat 4,84 m va thap nhat d cong thirc CT5 cung dat 3,84 m. Vdi cac tri sd trung binh ve dudng kinh tan nhu vay chung td rimg d tdt cd cac cong thiic thi nghiem da giao tan kha manh so vdi cu ly trdng la 3 x 3 m.
4 . KET LUAN
- Dat d khu vuc thi nghiem rat chua (pH^ci ~ 3,57-3,73), ham lugng miin d miic ngheo den trung binh (1,10 - 2,53%), hdm lugng ni to tdng sd (Nts) b miic ngheo den trung binh (0,063 - 0,155%); ham luang PaOs d l heu d miic rdt ngheo (<3 mg/100 g ddt), ham lugng K^O de tieu d miic tir ngheo den tning binh (6,6 -17,4 mg/100 g dat).
- Sau 1 nam trdng vdi 5 cong thuc bdn Idt phan khac nhau, ty le sdng trung binh dat 92,59%, dudng kinh trung binh (D13) dat 2,79 cm, chieu cao tnmg binh (Hvn) dat 1,89 m, dudng kinh tdn (Dt) dat 1,22 m; tdt nhdt d cong thirc bdn lot 500 g NPK/hdc vol dudng kinh dat 3,47 cm, chidu cao dat 2,11 m, duong kinh tan dat 1,42 m; kem nhat d cdc cong thiic khong bdn phan vdi cac tri sd tuong iing la 2,34 cm, 1,73 m
va 1,17 m.
- Sau 1 nam tuoi, ham luong m to tong so (Nts) trong la Keo tai hrgng cao hon nhieu so vdi 6 trong ddt nhd khd nang cd dmh dam sinh hgc, dao dong tii 1,152 - 2,612%; ham luang P^Oj tong sd trong Id cao gap tir 1,5 - 2 lan so voi d trong dat, dao dpng 0,270 - 0,624%; ham lugng P^Os trong ddt thap vd d trong la cao, chimg to nhu cdu P2O5 cua Keo tai tuong rat Idn;
ham lugng K2O trong dat d muc ngheo den trung binh nhrnig trong la lai thap hon nhieu, dao ddng 0,121 - 0,265%, chiing td nhu cdu K2O khdng Idn. Vi vay, khi trdng rimg Keo tai tugng d day can phai bo sung P2O5.
- Sau 2 nam tudi, tiic la sau 1 nam bdn thiic vdi 9 cong thiic khac nhau, ty le sdng trung binh toan thi nghiem dat 88,72%, dudng kinh (Dj 3) trung binh dat 7,58 cm, chieu cao trung binh (Hvn) dat 6,56 m, dudng kinh tdn trung binh (Dt) dat 4,38 m; giiia cac cong thuc bdn thiic da cd su khde nhau rd ret, cac cong thiic bdn lan (P2O5) luon luon tdt hon cac cong thirc khong bdn lan, tdt nhat d cong thtrc bdn thiic 0,1 kg K2O + 0,4 kg P2O5 vdi dudng kinh dat 8,43 cm, chieu cao dat 6,81 m; kem nhat d c6ng thirc kh6ng bdn phan lam ddi chiing chung vdi cdc trj sd tuong ung la 6,77 cm va 6,20 m.
TAI LIEU THAM KHAO
1. Bd Nong nghiep va PTNT (2018). Quyet dinh sd 1187/QD-BNN-TCLN ngay 3/4/2018 ve viec cong bd hien trang rimg toan qudc nam 2017.
2. Bg Nong nghiep va PTNT (2013). Quyet dinh sd 1565/QD-BNN-TCLN ngay 8/7/2013 phe duyet de an tai co cdu nganh lam nghiep.
3. Nguydn Huy Son, Pham Dinh Sam, Vu Tien Lam, Hd Trung Luong (2018). Ket qui budc dau nghien cdu co sd khoa hoc bdn phan cho rimg tiong Keo lai a Quing Ninh. Tap chi Khoa hgc Lam nghiep, sd 4 nam 2018, trang 107-115.
4. Simpson, J. A. at al (2000). Effect of site management in A mangium plantation on thecoastal lowlands of subtiopical Queensland, Austraiha. In:
Site management and producstivity in tropical plantation forests. (Eds: E. K. S. Nambiar, C.
Cossalter, A Tiarks and J. Ranger: workshop proceeding, 7-11 December 1999, Kerala, India, p 61- 71. Centre for International Forest Research, Bogo, Indonesia, p. 73-82.
KHOA HOC CdNG NGHE
5. Nguyen Hai Tudt va cac cong su (2006). Phan productivity of Acacia hybrid plantations for a range tich tiidngk^ tiong lam nghi$p. NXB Ndng nghiep. of climates and soils in Vietnam, Forest Ecology and
6. Trieu Thai Hung, Auro C. Almeidac, Aheta Management.
Eylesa.Caroline Mohammed (2016). Predicting
PRELIMINARY RESULTS OF FERTIUSER APPUCATION IN Acada mangium FOR SAWLOG PRODUCTION IN QUANG NINH PROVINCE
Vu Tien LamS Nguyen Huy Son^ Pham Dinh SamS Ho Trung Luong^
' Silviculture Research institute (SRI)
^ Non Timber forest Products Research Centie (NTFPRC) Summary
Acacia mangium is a major plantation tree species m Vietnam. One of the most important technical measures to increase the productivity of the plantation is fertilised application. The study was conducted in Quang Ninh province. North Vietnam to examine the effect of fertilsier apphcation on productivity of A man^/um planted as for sawlog production. The soil properties in the expenmental site were low to medium with acidic sod (pHKCl ~ 3.57-3.73), humus content (from 1.10 to 2.53%), total nitrogen content (Nts) (0.063- 0.15%); PjOg content fless than 3 mg/lOOg soil) and K2O content (from 6.6 to 17.4 mg/lOOg). Results showed that after one year of planting with 5 different fertiliser regimes, the average values of survival rate, diameter (D^j), height (Hvn) and crown diameter (Dt) were 92.59%, 2.79 cm, 1.89 m and 1.22 m, respectively. The highest tree growth was observed in fhe fertUser treatment which was apphed as 500 g of NPK (16: 16:8) per tree, with D,,= 3.47 cm, Hvn = 2.11 m, Dt s 1.42 m; while the slowest growth of the plantation was found in the control (ml-fertiUser) treatment. At the beginning of ihe second year, additional of PaOj and K^O was impplemented. The average value of survival rate, D,.,_, Hvn and Dt at age two years were 88.72%, 7.58 cm, 6.56 m and 4.38 m, respectively. The tree growth m all fertiliser treatments were significantly higher than that in the control treatment (nil-P^Oj) of which the highest value of D1:, (8.43 cm) and Hvn (6.81 m) was obtained in the treatment applied as 0.4 kg VJd^ per tree. The results mdicated that application of phosphorus, especially at planting, is nessesary for sustaining productivity of A mangium plantation.
Keywords: Acacia mangium, fertiliser application, growth, Quang Ninh province.
Ngudi phan bien: PGS.TS. Nguyen Minh Thanh Ngay nhan bdi: 8/4/2019
Ngdy thSng qua phan bien; 8/5/2019 Ngdy duyet dang: 15/5/2019
