fCHOA HOC CdNG N G H |
CAU TRUC SIIXIH KHOI CAY CA THE V A QUAIXI T H £ RUIXIG OUOC {Khizaphara aplculta B l u m e ) TAI CA IVIAU
Nguydn Thi Ha\ Vi6n Ngpc Nam^
T6MTAT
Nghian ciiu sinh khdi de xac dinh kha nang tich iQy cac bon cua rimg 1^ mot yeu cau khach quan nhdm cung cap m$t so co sd khoa hoc cho viec dmh gia rimg Ihong qua gii tri dich vt^ mdi frudng. Bat vidt cong bo nhang kdt qua nghien cuu duoc thuc hien tai rimg nggp mSn tinh Ca Mau, la noi rimg Dudc chiem uu thd vd xac dinh sinh khdi cay ca thd va qudn the rimg Dudc theo ckc bg ph&n la sinh khdi than cay, canh, la vk sinh khdi rl fren mat dat theo co kinh va cap tuoi rimg. Kdt qua nghifin ciiu cho thdy, ti le sinh khdi fhan khs cua cay Dudc chiem binh quan la 74,5%, bidn ddng 60,8 - 93,4% cda tong sinh khdi; ti le sinh khdi canh khd la 15,7%, bidn dong 3,3 - 26,4%; sinh khdi rd la 7,4%, cdn lai ti 1§ sinh khdi la la 2,5%, bidn dpng tir 0,9 - 12,4%. Cau tnie sinh khdi than frong qudn the la 79,5%, bidn ddng 74,2 - 84,2%; sinh khdi oia canh trung binh chiem 10,5% bidn dpng, 7,5 - 12,4%; sinh khdi rd chidm 5.4%, bidn dgng 4,4 - 6,4%; sinh khdi la chiem 4,6%, bidn dpng 3,6 ddn 6,1%. Tong sinh khdi oia quan the frung binh dgt 191,1 tanAa, tang dan tir co kinh nho ddn cd kinh ldn (49,6 - 357,4 tan/ha). Tong smh khdi cua quan thd d cdp hidi I la 86,1 tan/ha; cap tudi II la 162 tdn/ha, cap tuoi III la 207,7 tan/ha, cap tuoi IV la 276,1 tdn/ha, cap tudi V la 321,4 tan/ha va fren cap tudi VI la 357,1 tan/ha.
Tir kho^ Sinh khoi, rung duoc, rungng$p man, Ca Mau.
I.BATVANflE
Rimg ngap man d mui Ca Mau la khu ritng ngap man phong phti nhdt eua nudc ta, chiem vi tri quan frong, ddng thdi, ed vai frd to ldn vd kinh td va sinh thai mdi trudng. Dudc {Rhizophora apiculta Blume) la loai cay chidm uu thd frong rimg ngap man va tap trung nhidu d khu vijre phia Nam Viet Nam, dac bigf la d tinh Ca Mau. Trong nhiing nam gan day, vai frd ctia rimg frong vide hap thti CO2, giam nhe phat thai khi nha kinh vd vdn dd thuang mgi hda cae gia tri hap thti CO2 cua rimg duac sti quan tam ciia cgng ddng qudc te eung nhu d Viet Nam. Dd gdp phan xac dinh kha nang tich luy C va vai frd sinh thai mdi trudng ciia rimg ngap man, vigc xac dinh sinh khdi eua rimg ia mdt vigc iam quan frpng dau tien lam co sd cho nhiing phep tinh udc lupng tni lupng C ciia hg sinh thai rimg. Vi vay viec nghiSn ciiu ket cau sinh khdi ciia rimg Dudc tai tinh Ca Mau se ddng gdp mgt phan dang kd frong viec ctmg cap sd ligu ve cau tnie va md hinh udc tinh sinh khdi ciia ning lam CO sd xdc dinh khd nang tich liiy C cua rimg, cung cap thdng tin frong vi6c tham gia cac dtj an cd USn quan ddn giam phat thai tir mdt ning va suy thoai rimg va bdo tdn da dang sinh hoc (REDD*) frong
' Tnrdng Dai hoc Lam nghiep
^ Tmdng Dai hpe Ndng Lam TP. HCM
"luong lai.
2 . VAX UEU VA PHUDNG PHAP NGHlBy CUU
Nghien cuu dupc tidn hanh fren ddi tupng rimg Dude {Rhizophora apiculta Blume) tai Cd Mau tir edp tudi I (cap tudi nhd) ddn cap tudi VI (cap tudi ldn) (mdi cdp tudi each nhau 5 nam tinh tir liic bat dau frdng hoae tdi sinh ttr nhien). Nghign cthi tap trung xac dinh cau tnie sinh khdi cay ca thd va quan the rimg Dudc theo cac cb kinh va cdp tudi khae nhau, bao gdm sinh khdi theo cae bg phan than, eanh, la va rd frgn mat dat. Cac phuong phap nghien ciiu su dting la:
Phuang phip Up 6 tiiu cbudn vi tiiu thip sdMu ngoii hiin tnrdng
Lap d tieu chuan cd kich thude 50 x 50 m (2.500 m^) fr6n cac trgng tiiai rtmg khac nhau, frong mdi 6 tieu chuan, tidn hanh lap 5 d thu cap 10 x 10 m dien tich 100 m2vdi4dd4gdeval6dgiiiadd didu t ^ cac chi tieu smh tinrong va sinh khdi tiiuc vat Da thidt lap 56 d tieu chuan ngoai thuc dia (2.500 m^ vdi 280 d thir cap (100 m^.
Phuang phip do ddm smh khdi tirm vi Idy miu say tiong phong thi nghiem
Ap dung phuang phap giai tich tiian cay theo cd kinh, bdt dau vdi co kinh nhd nhat la 3 cm • i/m
134 C NONG NGHIEP VA PHAT TRIEN NONG T H 6 N - KY 1 - THANG 1 / 2 O I A
KHOA HOC C 6 N G N G H E
nhdt la 35 cm. Cay gidi tich la cky ti^u chudn binh quan vd dudng kinh, dupc bd tri ddu tir cd kinh nhd nhat ddn cd kinh ldn nhdt. Do didu kign Mp dia khd khan vd vigc ehat ha cay nhidu se anh hudng ddn san lupng va sinh thai ning cho ndn sd lupng eay tidu chudn duoc lya chpn chat ha la 46 cay dd dam bao vd mat thdng kd.
cay ti^u chudn sau khi ch$t hg, tidn hanh do chidu dai than cay, Dj 3 vd do tidt dign giua doan 1 m cho ddn hdt than cay, tdeh ridng timg bg phgn than, canh. Id, rd frgn mat dat va tidn hanh can, do sinh khdi tuoi 4 bg phgn ridng re ngay tgi hign trudng dd xac dmh sinh khdi tuoi frdn mgt ddt.
Sau khi xac dinh dugc smh khdi tuoi. tien hanh lay mdu timg bg phan cua cay, mdu dupc lay tai 3 vi tri gde. giiia than va ngpn. Sd mdu Idy la 4 bp phan x 3 mdu X 9 cay (frong tdng 46 eay, tidn hanh ehia 3 cdp h€X dign ngang bang nhau, mdi cdp lay 3 cay), khdi Itrpng ciia mdi mau la 5O0 gram, Mau lay xong can ngay bdng can dign tu de xdc dinh khdi lupng turn ban ddu. Mdu dupc bao quan cdn thgn franh lam roi rdt anh hudng ddn khdi lupng can ban ddu.
Phin ti'ch sinh khdi khd
Sinh khdi khd eua tiing bd phgn cua cay heu chuan (than, canh, la va rd fren mat ddt) duoc xac dinh theo phuong phap sdy d nhigt dp lOS^C eho than, cdnh vd rd. Id say b 80''C, mdu dupc say ddn khi trpng lupng khdng ddi. Sii dtuig can cd dg chinh xac 0,1 gam dd xae dinh sinh khdi khd ciia tiing mau.
Phuong phip xuly sdheu
Xic dinh hi sd chuydn ddi sinh khdi tiroi sang sinh khdi khd (P): Dtra frgn cac mdu phan tieh sinh khdi tgi phdng thi nghiem, hd sd chuydn ddi tii sinh khdi tuai sang sinh khdi khd kigt dupc tinh theo cdng Ihiic tdng quat sau:
Pi^ Wki Wti
Trong dd: Wki la khdi lupng khd kiet eua mdu i say d nhiet dd 105''C; Wti la khdi luong tuoi ciia mdu i trudc khi say.
J^c dinh sinh khdi khd timg bd pban (thin, dnh, la, ri): Sinh khdi khd timg bg phan (than, eanh, la, rd) eiia cay ca the giM tieh dupc xac dinh = Smh khdi tuoi x ti lg khd/tuoi theo cdng thiic:
W(Sk, Brk, Lk, Rk) = W(St, Brt, Lt. Rt) x Pi Trong dd: W(Sk. Brk, Lk, Rk) la sinh khdi khd cac bd phgn cay ca thd giai tich va W(St, Brt, Lt, Rt) Id smh khdi tiroi cua bp phgn i cay ca thd giai tich.
Sinh khdi khd cay ca the giai tich: Sinh khdi khd eay ed the dupc tinh bdng tong sinh khdi cua ede bp phan eua cay ck fhd (gdm sinh khdi khd ciia than, cdnh. la va rd mgt ddt).
Sinh khdi khd quin thd: Bdng tdng sinh khdi ctia cac c a y frong d tidu e h u a n va frdn h a .
3. KET QUA NGHBU CUU VII THAO LUAN 3.1. Kdt edu smh khdi khd eSy ed thd Tl le sinh khdi than khd cua cay ca thd Dudc chidm binh quan Id 74,5%. bidn dpng 60,8 - 93,4%; ti lg sinh khdi eanh khg Id 15,7%, bien dgng 3,3 - 26,4%;
suih khdi rg khd la 7,4%, edn lgi ti lg sinh khdi la la 2,5%, bidn dpng 0,9 - 12,4%. Kdt qua cQng cho thay khi dudng kinh tang ldn thi ly le % sinh khdi tiian cay eung tang theo frong khi su thay ddi t^ Id % ciia cac bd phdn khae (Id, rg) la khdng rd rdng, da sd khdng theo mgt quy luat nhdt dinh.
So vdi Thdng ba la (smh khdi gd chidm 74,4%
tiieo ket qua ciia Lg Hdng Phtic, 1996; smh khdi gd chidm 72.46% cua VO Tdn Phuang, 2011 ), Keo la fram (smh khdi gd chidm 78% theo kdt qua nghidn cim sinh khdi Keo la fram cua Vu Van Thdng, 1998) va loai Mam frang (sinh khdi gd chidm 91,32% theo kdt qua nghien ciiu smh khdi Mdm frdng ctia Vien Ngpe Nam, 2003) tiii Dudc cd ti lg smh khdi gd thap hon Keo la fram. Mdm frdng va eao han Thdng ba la.
•Wsk iWlk •Wbrk iWik
Hmh 1. Tl lg smh khdi khd than, cdnh. Id cSy Dudc
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 1/2016
KHOA HOC CONO HOM
TT 1 2 3 4 ."i fi 7 R 9 10 11 K
n
14^s
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 bb 36 37 38 39 40 41 42 43 44 45 46 TB
(cm)
4,77 5,41 5,73 6,21 6,37 6,53 6,68 7,00 7,32 7,64 7,96 8,28 8.59 8,91 9,23 9,55 9,87 10,19 10,35 10,66 10,98 11,14 11,46 11,78 12,10 12,41 12,73 13,05 13,53 13,69 14,16 14,32 15,28 15,92 16,55 16,87 18,94 21,65 23,87 26,10 28,17 28,65 30,40 35,17 12,91
(m)
9,0 9,0 9,0 11,5 10,7 10,7 11,6 13,0 11,9 11,9 12,5 13,7 13,5 14.9 15,6 13,6 13,6 13,5 14,3 14.8 14,8 15,5 15,0 15,0 15,0 16,0 15,0 14,5 16,8 15,5 11,9 15,8 16,0 17,5 19,4 15,8 19,0 18,0 19,5 25,5 23,0 20,5 23,0 24,8 14,9
Banjr 1. Kft clu sinh khdi khS c4v cA tbi Drak Sinh khoi kh6 tren mat M
w,»
kg 2,96 8,12 8,05 10,89 13,66 16,23 17,07 17,91 20,61 24,86 24,15 27,05 28,73 35,36 41,93 33,82 57,91 66,47 57,84 54,81 63,25 67,28 71,37 75,00 83,12 78,96 80,30 83,32 77,12 108,11 99,18 89,45 105,38 125,97 116,71 129,83 173,54 181,95 218,57 243,34 362,78 499.88 726,40 685,87 734,04 933,93 147,46
70,4
%
93,4 79,1 89,6 74,1 73,4 87,2 77,2 81,5 86,7 78,2 74,2 83,8 81,0 85,1 74,3 85,9 91,3 81.9 89,8 78,2 84,6 79,1 85,2 83,3 89,1 80,2 84,4 79,6 84,4 66,6 78,2 83,8 85,4 85,3 85.8 70,1 70,0 63,5 60,8 68,9 82,9 75,6 72,3 69,2 72,0 74,5
kg
w»
0,46 0,29 1,16 0,70 2,90 3,48 1,28 2,79 1,74 1,63 3,60 4,06 2,90 4,06 4,64 3,25 6,10 3.48 6,68 2,32 9,44 5,35 8,81 6,30 7,55 6,93 10,39 6,30 11,04 7,53 31,17 13,64 9,74 9,94 8.83 9,07 39,33 50,75 67,56 105,49 110,74 79,35 134,13 191,99 187,92 242,77 31,08
11,0
%
3,3 11,4 5,7 15,7 15,7 6,5 12,0 6,9 5,7 11,7 11,2 8,5 9,3 9,4 7,1 9,0 4,8 9,5 3,8 11,7 6,7 9,8 7,2 7,6 7,8 10,4 6,4 11,4 5,9 20,9 11,9 7,7 6,7 6,5 6,0 15,9 19,5 19,6 26,4 21,0 13,2 14,0 20,2 17,7 18,7 15,7
W kg 0,16 0,16 0,47 0,25 1,25 0,97 0,47 1,25 1,06 0,94 1,25 1,57 1,10 1,72 1,57 5,64 2,19 1,88 2,82 2,00 4,38 2,19 4,38 2,94 3,76 1,13 4,07 3,44 3,76 2,76 4,23 4,38 4,07 3,66 3,13 2,76 7,33 17,22 12,52 11,96 10,96 5,32 12,68 19,41 25,67 17,94 4,89
Ik
3,7
%
1,8 4,6 2,1 6,8 4,4 2,4 5,4 4,2 3,3 4,1 4,3 3,2 3,9 3,2 12,4 3,2 2,6 4,0 3,3 5,4 2,8 4,9 3,3 3,8 1,3 4,1 3,5 3,9 2,2 2,8 3,8 3,2 2,5 2,3 1,8 3,0 6,6 3,6 3,0 2,1 0,9 1,3 2,0 2,4 1,4 2,5
V,''
#»i..-
W kg 0,63 0,13 0,50 0,31 0,63 1,44 0,75 1,25 1,88 1,25 1,88 3,75 1,56 2,50 1,13 2,82 1,25 0,94 3,25 1,88 3,75 4,69 5,63 3,75 5,38 1,56 5,38 5,63 5,01 9,70 14,39 6,88 6,57 7,88 8,13 9,70 27,53 10,01 45,68 39,1, 41,92 1 18,77 87,60 51,93 112,63 103,24 14,61
t
"%
14,9 1,4' 4,9 2,6 3,4 6.5 3,8 5,4 7,4 4,4 6,1 10,3 4,6 5,7 2,3 6,2 1,9 1,3 4,6 3,1 4,6 5,9 6,2 4,3 5,4 1,8 5,4 5,7 5,2 7,6 9,7 6,0 5,2 5,3 5,9 6,4 11,1 3,9 13,3 98 8,0 3,1 9,1 5.5 10.6 ^
8,0 7 4 -
1
• «
_ _ W | k
k e ••'
4,2 "
S,? • 10,2 12,1 18.4 22,1 19.6 23,2 25,3 28,7 30,9 36,4 34,3 43,7 49,3 45,5 67,4 72,8 70,6 61,0 80,8 79,5 90,2 88,0 99,8 88,6 100,1 98,7 96,9 128,1 149,0 114,3 125,8 147,5 136,8 151,4 259 9
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N 6 N G NGHIEP V A PHAT TRIEN N O N G THON - KY 1 - THANG I / J Q ,
KHOA HQC C 6 N 0 M G H |
3.2. Kdt cdu sinh khdi khd qudn thd Dudc Ti Ie sinh khdi khd than cay cua quan tiid cao, chidm binh quan la 79,5%, bidn dgng 74,2 - 84,2%. Ti lg sinh khdi canh trung binh chidm 10,5% bidn ddng 7.5 - 12,4%. Tl le smh khdi la chidm 4,6%, bidn ddng 3.6 ddn 6,1%. Cdn lai sinh khdi la trung binh chiem 5,4% bien dgng 4,4-6,4%.
Tdng sinh khdi cda qudn thd trung binh dgt 191,1 tdn/ha, tang ddn ttr cd kinh nhd den cd kinh ldn (49,6 - 357,4 tdn/ha). Kdt qua eho thay, mat dp d cac qudn thd cd su khac nhau vd ciing cd su dnh hudng ddn smh khdi cua qudn thd rimg.
• W S i i W b r " W l \Vt
eho khdi luang sinh khdi cao nhat ma phu thude vao bd tri khdng gian hpp ly va str phat tridn dudng kinh ctia cay ca thd.
Hinh 2. Bidu dd ti lg smh khdi cac bg ph$n cua qudn thd Dudc
So sanh vdi ket qua nghidn ciiu sinh khdi tuoi rimg ngdp man cua Nguydn Hoang Tri, 1986 (rimg Dudc trudng thanh dat trung binh 171,3 tan/ha) va ciia Vign Ngpc Nam, 2003 (rimg Mdm frdng dgt tnmg binh 208,62 tan/ha) cho thdy smh khdi ciia rung Dudc d Ca Mau cao hon so vdi d ket qua nghien ctiu dkhu vtrc khac va cua loai eay ngap man khac.
3.3. Kdt cdu sinh khdi khd quan fhd Dudc theo cdkinh
Sinh khdi khd quan thd b khu vuc nghign ciiu phan bd fir cd kinh 3 cm ddn cd kinh 36 cm, frong do smh khdi phan bd tgp trung nhdt tir ca kinh 9 - 1 8 cm, frong dd sinh khdi chidm nhidu nhat la b cb kinh 12 cm vdi 50,2 tan/ha. O cd kinh 18 cm tuy sd cay khdng nhieu (63/3.539 cay) nhung lai cho luong sinh khdi kha cao (24,5 tan/ha), frong khi d ed kinh 3 cm va 6 cm cd sd lupng cay chidm phan nhidu nhung lupng smh khdi lgi rdt ttiap (3,5 - 16,4 tdn/ha). Didu nay chiing td, mat dp cay cao khdng
50
JO
1 .
20
10
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• Wl
• Wr
• TAGB iWSt •Wbi IWI i W r
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6 16 W 01 Dl 01
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9 40 33 04 01 02
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50 40 OJ ai 03
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48 37 05 02 03
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18 41 32 05 02 02
21 25 le 03 01 02
24 12 09 02 01 01
27 03 03 01 00 00
30 02 02 00 00 00
33 01 01 00 DO 00
36(1 01 01 DO OO DO
Hinh 3. Bidu dd phan bd sinh khdi cua qudn thd Dudc theo c& kinh
3.4. Sinh khdi khd qudn thd Dudc theo cdp tudi Sinh khdi ctia qudn thd Dudc bidn dgng theo dudng kinh va theo cap tudi. Sinh khdi eua ede quan thd tang dan Iheo cdp tudi cflng nhu tang len theo dudng kinh. Tong sinh khdi quan thd b cdp tudi I la 86,1 tdn/ha, cap tudi II Id 162 tan/ha, cap tiidi III la 207,7 tan/ha, cap hidi IV la 276.1 tdn/ha, cap tudi V la 321,4 tdn/ha va frdn cap tudi VI la 357,1 fan/ha.
• N/ha iTAGBltiln/ha)
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I N/ha 8395 2570 210 40 IS
• TAGBitan/ha) 33 38 09 03 02
Hinh 4. Bidu dd cdu tnie sinh khdi cua qudn thd Dudc cdp tudi I
Cap tudi cang tang tiii sd luong cd kinh frong qudn tiid cang tang. Didu nay cd tiid giai thich rang, mac dil rimg hi pha hiiy do bao sau nam 1978 va dupc frdng lgi nhung do khdng cd tac dpng, didu tiet vd mat dp nen ed su canh franh kha ldn vd khdng gian sdng, ddn ddn co kinh cd sir phan hda manh.
Bdn eanh dd, lap dia d khu vtrc nay am va cd sti Ign
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 1 /2016 137
KHOA HOC CdNG N G H £
xudng eiia thiiy tridu hgn tuc nen qua trinh tai sinh ttr nhien vdn didn ra thudng xuydn.
Danh gia sinh khdi timg cdp tudi, eho thay, d cap tudi I, quan the rimg Dudc chua cd su phan hda manh vd dirdng kinh. didu nay cd nghia la frong qudn thd chua cd hoae it cd sir eanh franh vd khdng gian dinh dudng. Qudn thd cd smh khdi phan bd tir cd kinh tir 3 cm dd'n cd kinh 15 em cd tdng smh khdi fren mat dat 86,1 tdn/ha vdi mat do trung binh la 11.230 cay/ha; lupng sinh khdi tap trung cao nhat la CO kinh 6 cm. mac du mgt dg phan bd nhidu nhat la d cd kinh 3 cm. Cdu tnie sinh khdi tuong ddi dn dinh ed dgng mdt dinh Igch frai vd phia cay dudng kinh nhd.
Sinh khdi khd eiia qudn the d cap tudi II tkp trung chu ydu d cd kinh 6 - 1 2 cm, cao nhdt la ed kinh 9 cm, cd tdng sinh khdi la 75,8 fan/ha. Smh khdi d cap tudi nay ed edu tnie mot dmh, phan bd kha chuan.
Hinh 5. Bidu dd cdu tnie sinh Mi6i eiia qudn thd Dudc c ^ tudi n
Tuong tu, cap tudi III, smh khdi quan thd tap frung chii ydu a cd kinh 9 cm va 12 cm, cao nhat la d cd kinh 12 cm (69,3 tdn/ha), cau tnie smh khdi cung cd dang mpt dmh, Igch fr^ vd ed kmh nhd. Tdng sinh khdi ma quan thd rimg dat dupc a cap tudi III la 207.7 fan/ha. Trong dd. smh khdi than la 167,9 tdn/ha, sinh khdi eanh la 20,5 tan/ha, smh khdi la la 8,5 tan/ha, edn lai sinh khdi rg la 10,8 tdn/ha.
So vdi kdt qua d rimg cdp tudi III, sinh khdi ning d cap tudi IV gia tang nhanh chdng theo ca kinh.
Mat dp sd cay d cd kinh nhd giam xudng. Cau tnie
rOmg mgt dinh, dat chuan. Sinh khdi tap trung <? cd kinh 12 cm ddn 18 cm. cao nhat la cdkinh 15 cm. dat 72,7 tiin/ha vdi mat dp 414 cay/ha.
70,00 60.00 . 50.00
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10.00 1000 .00
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e 9 992 1 1273 020 064 12 719 069
15 183 030
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Hinh 6. Bidu dd cdu tnie sinh khdi ciia qudn thd Dudc edp hidi UI
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30JXI 20,0D 10,00
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301 541 006 027
12 15 18 556 414 239 056 073 063
21 24 85 26 033 014 27011 5 004
Hinh 7. Bidu dd cdu tinie sinh khdi oia qudn fhd Dudc cap tudi IV
sajM 8000 70MI EOJXI 1 saoo '^ 40H1 saoo 20.00 loao
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24 3 00G 36 03 9 384 20 1!
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6 9 12 1 GO 353 367 2 06 17 36 3
5 IS V 173 6 SO 21 1S3 63 24 in 56 27 33 23 30 40 37
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33 13 15360 13 18
Hinh 9. Bidu dd edu tnie sinh khdi ciia qudn thd Dudc cdp hidi frdnVI
O cdp tuoi IV vd cap tudi V, can tnie sinh khdi cd dgng ragt dinh va cd phan bo tuong ddi dat chuan, sinh khdi tdp trung chti ydu a cb kinh 15 cm va 18 cm. So vdi kdt qua d rimg edp tudi fren VI, cau tnie sinh khdi quan the rimg Dudc da cd su bidn ddng.
Cau biic smh khdi luc ndy phan hda nhidu ^ n h , mdt dinh tap trung d ed kinh 21 cm cd sinh khdi cao nhat frong quan fhd (62.5 tdn/ha), dinh thii 2 tap frung d cd kinh 30 cm (40 tan/ha). Didu nay eho thay rimg da thanh thuc, tiid hign mot can tnie khdng bdn vtmg, can cd su khai tilde, didu chinh edu tnie hpp ly, bdn vung thtie day ldp eay kd ckn de tang cudng tich luy sinh khdi cho rimg gdp phdn nang cao gia tri sinh thdi ciia rimg.
4.ieLUM
Ti lg sinh khdi cac bg phan fren mat dat cua cay Dudc ciing nhu cua qudn fhd Dudc la rat khae nhau, chidm nhidu nhat Id bd ph$n sinh khdi than, tidp ddn Id sinh khdi canh, sinh khdi rd fr6n mat dat va chidm it nhdt la sinh khdi la.
Tdng sinh khdi cua foan lam phan ed su bidn dpng mgnh giua cac ed kinh va cap tudi, tdng sinh khdi qudn fhd tang len theo cd kinh va cap tudi.
M^t dp eay frong quan thd nhidu khdng anh hudng ldn ddn tdng sinh khdi quan thd ma chti ydu phti fliudc vao su bd fri khdng gian hop ly frong qudn thi.
Cau tnie sinh khdi cua quan thd da sd mgt dinh vd ed edu tnie tuong ddi ehuan d cap tudi II, cdp tudi IV vd cap tudi V, b cdp tudi frdn VI (rimg fir 30 nam frd ldn) bat ddu cd edu tnie phan hda nhidu dinh, thd hign cau tnie ning khdng bdn vung, thieu ldp cay kd cgn. Do do, d cap tudi nay can ed su didu ehinh dd tang sinh khdi eho rimg.
Tdng sinh khdi vd bidn dp phan hda cd kinh tang dan theo cap tudi, d cdp tudi I rimg cd tdng sinh khdi nhd nhat, tidp ddn Id cdp tudi II, UI, IV, V; cdp tudi frdn VI cd tdng sinh khdi eao nhdt, tuy nhidn liic nay miic dd chdnh Igeh sinh khdi so vdi cap tudi V da giam.
TAI LEU THAM KHAO
1. Vien Ngpc Nam, 2003. Nghiin cuu smh khdi va nang sudt sa cap qudn thd Mim trang (Avicennia alba BL.; tii nhiin tai Can Gid, TP. Ho Chi Mmh.
Lugn an tidn si khoa hpe ndng nghigp. Vien Khoa hpe Lam nghidp Vigt Nam. 172 trang.
2. Vu Tan Phuong va cs, 2007. Bio cio tdng kdt di tii "Nghiin cua lugng gii kinh te gii tri moi trmmg vi DVMTcua mdt sdloai nmg chu yi'u d Viet Nam". Trung tam Nghidn ciiu Smh thai vd Mdi trudng rimg (RCFEE). Hd Ndi.
3. Le Hdng Phtic. 1996. Danh gia sinh trudng, tang tiudng, sinh khdi, nang suat rung thdng ba li (Pinus kesiya Royle ex Gorden^ vung Di Lat, Lam Ddng. Luan dn Phd tidn si Khoa hoc Ndng nghigp. Vign Khoa hpe Lam nghigp Viet Nam, 152 trang.
4. Dang Trung Tan. 2001. Smh khdi rimg Dudc {Rhizophora apiculata). Kit qui nghiin cuu khoa hgc vi ky thuit Lim nghiip giai doan 1996 - 2000.
Vien Khoa hpe Lam nghigp Vigt Nam, Ha Ndi.
5. Vu Van Thdng, 1998. Nghiin ciiu easd xic duih suih khdi ciy ci le vi lim pban Keo la tiam (Acacia auriculiformis Cunn; tai Thai Nguyin Luan van tiiac si khoa hpe lam nghiep. Dai hoc Lam nghiep, 65 frang.
NONG NGHIEP VA PHAT TRIEN NONG T H 6 N - KY 1 - THANG 1 /2016
KHOA HOC CONG N G H |
BIOMASS STRUCTURE OF Rhizophora apiculata BLUME EST CA MAU PROVINCE Nguyen TTii Ha, Vien Ngoc Nam Summary
Biomass research to detemime the ablLly of forests accumulate carbon as an objective requirement to provide a scientific basis for the valuation of forest environmental service value. The article are published the results of research have been earned out m mangrove forest of Ca Mau provmce, where Rhi^iphora apiculata is dominant, about the biomass of individual frees and free population following the biomass of the trunk, branches, leaves and aboveground prop root based on the free diameter and forest age classes. The study results indicated that, the rate of tree parts of biomass was' Stem (74.596), branches biomass (15.7%), prop roots (7.4%) and leaves biomass (2.5%). Biomass structure of forest was; stem (79.5%) (from 74.2 to 84.2%), branches (10.5%), prop roots (5.4%) and leaves (4.6%). The averaged total biomass of the forest is 191.1 tons/ ha, increasing from small diameter to large diameter (from 49.6 to 357.4 tons/ha). The total biomass of the forest at age class I was 86.1 tons/ha, age class II was 162 tons/ ha, age class HI was 207.7 tons/ha, age class IV was 276,1 tons/ha, age class V was 321.4 tons/ha and above age class VI was 357.1 tons/ha.
Key words: Biomass, Rhizophora apiculata, mangrove forests. Ca Mau.
Ngudi phan bign: PGS.TS. Phgm Xuan Hoan Ngdy nhdn bai: 16/11/2015
Ngay thdng qua phan bign; 16/12/2015 Ngay duygt dang: 23/12/2015
NONG NGHIEP VA PHAT TRIEN N O N G THON - KY 1 - THAN© i
