Top chi Khoa hgc TrudngDgi hgc Cdn Tho Phdn.4: Khoahgc Tunhien. Cdng ngbe vd Mdi Iru&ng: 29(2013): 37-44
^ ^ Tap chi Khoa hoc Tru'dng Dai hpc Can Thd website: sj. ctu. et^u. vn
CAC YEU TO MOI TRlTonSG v A CAC THANH PHAN DAM TRONG RlTNG NGAP MAN TAI CON ONG TRANG, TINH CA MAU Vo Nguon Thao^, Truang Thi Nga^ va Huynh Trpng Khiem^
' Khoa Mdi truang & Tdi nguyen Thiin nhiin, Trudng Dgi hoc Cdn Tha
^ Trung tdm Nghien cicu vd Ifng dung ky thudt rimg ngdp Minh Hdi, tinh Cd Mau Thong tin chung:
Ngdy nhdn: 23/05/2013 Ngdy chdp nhdn: 24/12/2013 Title:
The environmental factors and nitrogen forms in Ong Trang hillock, Ca Mau province
Td khda:
Yeu td tndi tnrdng, thdnh phdn dgm. rimg nggp man,
cdn Ong Trang, mua Keywords:
Environmental factor, nitrogen form, mangrove forest, season
ABSTRACT
Research was carried out af the Ong Trang hillock, Ca Mau province. The results showed that soil temperature, pH and Eh ranged fi-om 28.2(fC to 28.24"C, 7.10 to 7.38 and -176 to 60 mV in the rainy season, and ranged from 28.68"C to 28 74"C, 6.62 to 7.05 and-161 to 79 mVin the dry season.
The total nitrogen and N-NH.,' in the soil were of high concentration in the studied site oflhe Rhizophora apiculata (0.20% ± 0.018 and 26.80 mg/kg ± 4.79 in the rainy season and 0.18% ± 0.014 and 11.43 mg/kg ±2 98 in the dry season). At Bruguiera parviflora site, high concentration of N-NOf was found (1 37 mg/kg ± 0.15 in the rainy season and 0.48mg/kg ± 0.14 in the dry season). The water qualities including temperature, pH, DO, and salinity were characterized as 27.20''C to 27.30''C, 7.02 lo 7.21, 2.78mg/L to 2.87 mg/L, and 19.30%o to 19.40%o respectively in the rainy season and 27.76"C to 27.84''C, 7.17 to 7.38, 3.22 mg/L to 3 42 mg/L, and 29.12%o to 29.26%o respectively in the dry season. The concentration of N-NHj" in the water was high at the site gf Rhizophora apiculata (0.360 mg/L = 0.026 in the rainy season and 0.176 mg/L ± 0 012 in the dry season). The water concentration of N-NOs was high at the Bruguiera parviflora site (0.022 mg/L ± 0.004) in the dry season.
TOM TAT
Nghiin cuu dugc thuc hiin tgi 3 vi tri phdn bd cua Mam trdng. Dude doi vd Vet tdch. Kit qud cho thdy nhiit dg, pH vd Eh ddt vdo miia mua dao ddng tir 28.20°C - 2S.24"C. 7,10- 7.38 vd -176 - 60 mV vd vdo miia khd dao dgng n> 28,68^C - 28,74"C; 6.62 - 7,05 vd -161 - 79 mV. Diim nghien ciru Dude ddi cd hdm lugng dgm tdng cao (0,20% ± 0,018 vdo miia mua vd 0.18% ±0,014 vdo miia khd) vd N-NH/ trong ddt dao dgng 26,80 mg/kg = 4,79 vdo miia mua vd ll,43mg/kg ± 2,98 vdo mua kho. N-NOs' cd gid th cao d diem nghien ciru Vet tdch (1,37 mg/kg ± 0,15 vdo miia mua vd 0,48 mg/kg ± 0,14 vdo mua khd). Nhiet do nudc miia mira tir 27,20"C - 27.30"C;
pH 7,02 - 7,21; DO dao dgng 2,78 mg/L - 2,87 mg/L vd do mgn 19,30%o - 19.40%o. Miia kho dao ddng tit 27,76"C - 27,84"C; 7,17 - 7,38; 3,22mg/L - 3,42 mg/L vd 29.12%o - 29.26%o. Hdm luting N-NHi trong nudc cao d diim nghien ciru Dude ddi (0,360 mg/L ± 0,026 vdo mlta mua vd O.l'O mg/L ± 0,012 vdo miia khd). Hdm lirgng N-NO3' trong nudc cao d nai phdn bd Vet tdch (0,022 mg/L ± 0.004 vdo mua khd).
Tap cbi Khoa bgc Tnrong Dai bgc Cdn Tha 1 G l d l T H I f U
Rim^ nggp man li he sinh thai quan trpng cd ndng suit sinfa fapc cao d vimg ciia sdng, ven bien nhiet ddi (Phan Nguyen Hdng, 1999). Trong he sinfa thai nay dgm thudng Id chit dinh dudng hgn chi nhit (Vazquez et al, 2000). Mac dii v|y, rimg ngap man van cd nang suit cao do sy tuin hoin chit dinh dudng d day rdt hieu qud. Sy pfaan huy vit ryng ciia cdy ngap man da cung cap lugng dgm dang kl cho dit rimg. Vd diy ciing chinh la ngudn thitc in gidu chit dam cho cic loai sinh v|t cu tni trong rimg ngdp man vi cdc he sinfa thai ke can (Nguyen Thi Hdng Hgnh vi Mai Sy Tudn, 2005).
Dgm faiiu co qua qua frinh khoang hda sl cung cip cho sinh vat dudi dang amoni (NH4'*), nitrite (NO2") vd nitrate (NO?'). Sy frao ddi chit dinh dudng giiia rimg ngdp mgn vdi cic viing lan cgn phy thupc nhiiu vio cic yeu td nhu dja hinh, kieu tham thyc vit, dilu kiln khi hdu, chl dp thiiy friiu... (Alongi et al, 1992). Nghiin ciiu vl "Cdc yiu th mdi trudng va cdc thdnh phan dgm trong rung nggp mdn tgi cdn Ong Trang, dnh Cd Mau "
di dugc thyc hi|n nhdm danh gii thanh phan dinh dudng dam trong dit va nudc din sinh thai rimg nggp mgn va tim failu mdi liln hi giiia cac thanh phdn dam frong dit vi nudc vdi ede yeu td moi frudng tgi cdn Ong Trang
2 PHUONG TIEN VA PHU'ONG PHAP 2.1 ThM gian va dia diem nghien cOru Nghiin ciiu duge thyc hien tir thing 10 nam 2011 din thing 03 nam 2012 tai con Ong Trang, huy|n Ngpc Hien. tinh Ca Mau.
2.2 Chpn vj tri nghien ciru
Cic diim nghiin ciiu dugc bd fri tai cdc vi fri
Bang 1: Phuong phip do dac ^ a phan tich cic chi lilu mdi trudng
PhdnA. Kboa hgc Tu nbien. Congnghfvd Mdi tru&ng- 29 (2013): 37-44 phin bd chu yeu ciia cdc lodi cdy rimg ngdp man U Vet tdch, Duoc doi va Mim frang theo hudng tir khu vuc diu cdn den khu vyc mui cdn. Mdi diem nghien ciiu Igp 5 6 lilu chuan (20 m x 20 m) theo nguyin tic dudng eheo gdc. mdi d tieu chudn each nhau 50 m.
2.3 Phuxmg pfaap do dac vd pfaan ticfa cac chi tieu mdi tnrcmg
Viec thu mdu va do dac cdc chi tieu moi fru6ng dat vd nudc dugc thyc hien hai dgt vdo miia mua (thing 10 ndm 2011) va miia khd (thing 3 nam 2012).
Cic chi lilu mdi trudng nudc dugc do liic nuoc triiu cao nggp nin rimg vd cdc chi tiiu moi tnrfimg dit dugc do liie nudc triiu da rut khdi nin rimg.
Thdi gian do dac vd thu mdu yao liic 9 - 10 gio sdng. Ci mdi 6 tieu chudn se tiln hdnh thu 5 mlu ddt va 5 miu nudc, sau do frdn lgi thdnh mit mlu dit vi mpt mlu nudc.
Mau la cay dugc thu 3 mdu d m5i diim ngjiiln ciiu vdo miia mua (thdng 10 ndm 2011), bao gim:
li xanh (la tuoi vdn cdn d fren cay), la vang (la m(n rung xudng nin rimg nhung chua phdn hdy) vi la ndu (Ii ryng dudi nen rimg va da phdn hiiy).
Miu ddt dugc sir dyng de phan tich dam tdng la mau ddt kh6 khlng khi, mdu dit dugc s^ dyng dS phdn tich N-NH^"" vd N-NO3" la mau dit tuoi va mau li dugc dugc sur dyng dl phan tich dgm ting la mdu da dugc siy khd d nhiet dp 60''C. Phucmg phap do dgc vi phdn tich cac chi tiiu dugc frinh biy cu the d Bang 1.
Chi tieu Phuung phdp
Nhiet dp, pH va Eh dit N tdng frong dat N-NH^"" trong dit N-NOj" frong dit Nhiet dp. pH. DO va dp mdn nudc
N-NHj" frong nudc N-NOs' trong nudc N tdng frong la cay 2.4 Xulysolifu
Cac so lieu phan tich. do dac duoc tong hgp
Su dung may do vdi dau diln cyc thiiy linh theo phuong phip cua Wilkinson vi Baker (1997) d do sdu khoang 5 - 10 cm
Kjeldahl
Indophenol blue, so miu d budc sdng 640 nm.
Khii hydrazine sulfate, so miu d budc sdng 543 nm Do tgi hiln trudng bang may do da chi tiiu U-IO (Nhdt) So raau Indophenol blue, so mau d budc song 660 nm So raiu Salicylate, so maud budc sdng410nm Kjeldahl
bdng phan mem Excel 2003 vi dugc xii ly tfadng ke (phan tich T - test v i Duncan) bdng phan mem SPSS 13.0 d mirc y nghTa a = 0,05.
Tgp chi Kboa hgc Tnr&ng Dgi hgc Cdn Tha Phdn .i Kboa hgc Tu nlnen. Cong ngbe vd .Moi iruang: 29 12013i 37-44 3 KET QUA VA THAO LU4.N
3.1 Cdc yeu to moi tnrdng lien quan din su- cfauyen hda dam va cac thanfa pban dam troDg dat
3.1.1 Dg ngdp triiu
Kit qud d Bdng 2 cfao thdy cao trinh ragt ddt Bang 2: Cao trinfa dat d cdc diem ngfaien cuu
cao dan tir diem nghien cuu Mara trdng den diim nghiin cihi Vet tach. nghta la tir khu vuc raui cdn din khu vyc dau cdn. Neu Idy diem nghien ciiu Mira trdng lam chudn, dllm nghiin ciiu Dude ddi cd cao trinfa Id 25,9 cm vd diim ngfailn ciiu Vet tich CO cao frinh Id 46,7 cm.
Diem nghien ciru Cao trinh dat ngay 03/11/2012 (luc Cao trinh mat dat (niu ldy diem trieu cao nhat) (cm) Mam lam chuan) (cm) Mam frdng
Dude ddi Vet tich
-53.8 -27,9 -7,1
0.0 25.9 46,7 Diem nghien eiiu Mam trdng cd sd ngdy nggp
trieu binh quan Id 28 ngdy/tfadng va so ldn ngap trieu binh quan/thang la 42 ldn, tiip din tai noi phan bd Duoc ddi, 13 ngay/thang va tin suit ngap 16 lin/tfadng) vi tfadp nhdt la tai kfau \-yc V?t ticfa (6 ngdy/thdng vi 6 Idn/tfadng).
3.1.2 Nhiit dg ddt
Nhilt dp dit cd gia fri tdng ddn tir diera nghien ciiu Mim tring din diem nghiin ciiu Vet tach va miia mua cd nfai|t dp thip han so vdi miia khd (Bdng 3).
Bang 3: Nhiet dp dat ("C) d cac diem nghien ciru Mam trang Dude ddi Vet tdch Miia raua 28,20*0,04" 28,22±0.04" 28.24±0.06^
Miia khd 28,68*0.02" 28,72*0,04*^ 28.74±0.04' Ghi chu: Cdc gid trj a cimg mgt hdng cd cimg chu edi (a. b. c....) thi khdng khdc biet coy nghia thdng ke (p>0.05)
Nfaiet dp dit vio miia raua giiia cic dllm nghiin ciiu Mdm fring (28,20±0,04"C), Duoc doi (28.22±0,04''C) vi Vet tdch (28,24*0,06^0) khdng khac bill cd y nghia tfadng ke (p>0,05). Vao raua khd. nhiet do dat d diim nghien cihi Vet tich (28,74*0,04"C) khdng khic bilt cd y nghia thing ke (p>0.05) so vdi diim ngfailn ciiu Dude ddi (28.72±0,04**C) nhung Iai khdc biet ed y nghia thong kl (/?<0.05) so vdi diera nghiin ciiu Mam frdng (28.68±0.02''C). Nhilt dp dil d cac diim nghiin ciiu nhin chtmg thugn lgi cho ede qud trinh cfauyin hoa dam vd co frong dat.
3.1.3 pHddt
Kit qua kfado sdt d Hinh 1 cfao thiy pH dat cd xu faudng giam ddn tir dllm nghiin cuu Mira fring din diim nghiin ciiu Vet tich va miia mua cd pH dit cao hon so vdi miia kfad.
Hinfa 1: pH dat d cdc diem nghien ciru Ghi chii: Cdc gid tri a cdc col gidng nhau CO cung 1 chir cdi (.A. B. C hay a. b. c) thi khdng khdc biet co y nghTa thdng ke(p> 0.05)
Tri sd pH do dugc d diira ngfaien ciiu Mim frdng la 7,38*0.10 vao miia mua va 7,05*0,10 vao miia khd khdng khac biet cd v nghia thong ke
frang Duoc doi Vet lach (p>0,05) so vdi diim nghiin ciiu Dude ddi li 7.27±0.08 vao raiia mua va 6,88*0.11 vdo miia khd nhung lai khac biet cd y nghia thdng kl (p<0.05) so
Tap chi Khoa bgc Tnrdng Dgi hgc Cdn Tha Phdn A • Khoa hgc Tu nhien. Long ngn? va \toi truang- / y (JUIJ): y<-44 vdi d i i m nghiin ciiu Vet tdch Id 7,10*0,19 vao
miia mua vi 6.62*0.16 vio miia kfad. Gia tri pH dat d cac diira nghien ciru nhin chung thuin lgi cho su khoang hda nito, cd djnh dara, qud frinh amon hda va nifrate hda frong radi frudng ddt xiy ra.
3.1.4 Eh ddt
Kit qua d Bdng 4 cfao thiy Eh cd gid tri cao nhdt d vi tri cd dia hinfa cao nfait thupc khu vuc cuii mui cdn, noi phdn bo Vet tach vdi gii fri ghi nhin vao miia mua li 60 mV*l 1 vi vao miia kho Id 79 raV±12 . Tai noi phdn hi Dude ddi vdi gia fri Eh ghi nhgn vao miia mua li -143 mV±24 va vdo miia khd li -125 mV*28 Tai noi cd dia hinfa tfadp nhdt, Mdm trang vdi gia tri Eh vao miia mua la - 176 mV*25 va vao miia kho la -161 mV±23.
Bang 4: Eh dat (mV) d cdc diem nghien ciru Mdm trdng Dude ddi Vet tach Miia mua
Miia khd
-176*25' -161*23'
-143*24*' -125*28*'
60*11^
79*12"
Ghi chii Cdc gid Iri a citng mgi hdng co cimg chu cdi (a. b. c,...) tbi khong khdc biet cd y nghTa thong ke (p>0,05)
Gid trj Eh d diera nghiin ciiu Mdm frdng vd Duoc ddi mang gia tri dm. do do ham lugng NH4^
d hai diem nghien ciiu nay cd khuynh hudng chiira uu the ban so vdi d diem nghien ciiu Vet tdch. Cac kit qui niy liln quan din cao frinh, chl dp ngap trieu, tan suat ngap trieu nhu da trinh bay vd thao luin d trin
3.1.5 Hdm lifongdam tdng trong Id cdy vd trong ddt
Hdm lirgng dam ldng trong Id cdy Bang 5: Ham lugng dam tdng (%) trong la cay
Mam trdng Budc doi Vet tach Li xanh 1.79 1,03 1,06 Living 1.34 0,54 0,63 La nau 1J6 0^41 0,50 Ghi chu: Ld xanh Id Id tuai vdn con a tren cdy. Id vdng Id Id mdi rung xuong nen rirng nhimg chua phdn huy vd Id ndu Id Id rung du&i nen rirng vd da phdn huy
Kit qua nghien ciiu d Bang 5 cho thiy ham lugng dgm tdng trong la cay Mdm trang cd gia tri cao nhit (1.79% ddi vdi la xanh. 1.34% dii vdi la vang va 1,16% ddi vdi Ii ndu). tiep din la la cay Vet tich (1,06% ddi vdi li xanh, 0.63% doi vdi la vang vi 0.50% ddi vdi Id ndu) vd thip nhdt la Id cay Dude doi (1.03% ddi vdi Id xanh, 0,54% dii
vdi Id vang vi 0.41% ddi vdi li nau). Kit qua cho thdy hdm lugng dgm trong li xanh cao hon d tit ca frudng hgp. La niu da rung trin thim rimg bdt dau bi phan hiiy va bi mit dam do nudc thOy triiu vi dgm tir la sl la ngudn cung cip dinh dudng cho ddt va he sinh thdi bao gdra chuoi th^c dn. Ham lupng dara la Mim d 3 frgng thai deu cd khuynfa huong eao ban so vdi Dude va Vet. Dieu ndy rat cd y nghia trong thyc tl iing dung khi sy phan huy v|(
rung cua cay ngap min vd ddc biet la Mim cung cap lugng carbon vd dgm ddng kl cho ddt rimg La cay la ngudn thiic an gidu dam cho cdc dpng vat cir tni frong rimg ngdp man (Nguyin Thi Hdng H?inh Vfl c/v., 2005)
Hdm lucmg dgm tdng trong ddt
Bang 6: Ham lugng N t6ng (%) trong dat is cic diim ngfaien ciru
Mdm trdng Dirdc ddi Vet tich Muaraua 0,15*0.009'' 0,20*0.018* 0,14*0,011"
Mua kho 0,14*0,005" 0,18*0,014" 0,13*0,007'' Ghi cha- Cdc gid tri d cimg moi hdng cd cung chir cdi (a, b. c,...) ihi khdng khdc biet co y nghTa Ihdng ke (p>0.05)
Kit qui d Bing 6 cho thdy ham lugng dam tong frong ddt d cic dllm nghien ciiu deu d miic thap trir diim nghiin curu Dude ddi vio miia mua c6 ham lupng dam tong frong dit dgt mirc trung binh (Melson, 1961; trich dan bdi Ngd Ngpc Himg, 2004). Diim nghiin ciiu Dude ddi cd ham lupng dgra long frong ddt eao nhat vdi gid fri ghi nhgn 1^
0,20%±0,018 vio miia mua vd 0,18%*0,014 yao miia kho, tiep din la d diim nghien cuu Mira trang vdi gia fri Id 0,15%*0,009 vao miia mua va 0.14%±0,005 vdo raiia kfad va thdp nhit Id d diim nghiin ciiu Vet tich vdi giafri Ii0,14%*0,011 vao miia mua va 0,I3%*0,007 vao miia kho. Nhin chung dam tdng khdng thay ddi r6 ret theo mua.
3.1.6 N-NHi trong ddt
Hira lugng N-NHj"^ d diim nghien ciru Mdm trdng la 13,18*3,92 mg/kg vio miia mua v^
10,74*3,08 mg/kg vdo miia khd, d diim nghiin ciru Duoc ddi Ii 26,80*4,79 mg/kg vdo miia mua va 11.43*2,98 mg/kg vao miia kho va d diem nghien ciiu Vet tach la 15,86*4,77 mg/kg vdo miia mua vd 5,65*1,46 mg/kg vio miia khd. Kit qua cho thdy N-NH4* trong ddt o cac diim nghiin ciiu d raiie ngheo (Trin Vdn Chinh et al, 2010)
Tgp chi Khoa hgc Tru&ng Dai hgc Can Tha Phdn.4 Khoa hgc Tunhien. Cdng nghe vd .Mdi tnrang. 29(2013). 3/-44 Bang 7: Ham lirgng N-NH/ trong ddt (mg/kg) d
cac diem nghien cmi
Mam trdng Pudc doi Vet tdch Miia mua 13,18*3,92" 26,80*4,79" 15,86*4,77'' Mua khd 10,74*3,08" 11,43*2,98' 5,65*1,46'' Ghi chu: Cdc gid in a citng mdt hdng cd cung chir cdi (a, b, c,...) thi khong khdc biel cdy nghia ihdng ke (p>0.05)
3.1.7 N-NOs trong ddt
Hdm lugng N-NO3' frong dit cd gia tri cao nhdt
Hinfa 2: Ham lugng N-NO3" trong dat d cdc diim nghien cuu Ghi chu: Cdc gid Iri a cdc cgl cd citng 1 chu cdi (A. B. C hay a. h, c) ihi khong khdc biet co y nghia thong ke (p>0,05)
3.2 Cdc ylu to moi trudng lien quan den sy chuyen hda dgm vii cac thanh phan dam trong nirdc
3.2.1 Nhiit dg nudc
Kit qua khao sit d Bang 8 cho thiy nhi?! dp nudc d diim nghiin ciiu Mam trang khdng khdc bi|t cd y nghia thing ke (p>0,05) so vdi diem nghiin ciiu Dude ddi nhung lgi khdc biel cd y nghia thing kl (p<0,05) so vdi diem nghien ciiu Vet tdch.
Bdng 8: Nhift d$ nirdc ("C) d cac diim nghien ctru
Mdm trang Pud'c ddi Vet tdch Muaraua 27,20*0.00" 27,24*0.05" 27,30*0,00^
Mitakhd 27,76*0,05" 27.78*0,04"'' 27,84*0,05"
Ghi chii: Cdc gid tri a cimg mgt hdng ca cting chu cdi (a. b. c,...) thi khdng khdc biet cdy nghTa ihdng ki (p>0.05)
Nhiet dp nudc thdp nhdt d diem nghien ciiu Mim trdng (27,20''C±0,00 vio mua mua vi
d diem nghiin ciiu Vet tich (1,37*0,15 mg/kg vio miia mua va 0,48*0,14 mg/kg vio miia kfad). tilp din la d diem nghien ciiu Dude ddi (1.03*
0,29 rag/kg vao miia mua vd 0.19*0,10 rag/kg vao miia khd) vi thap nhit Id d diim nghien ciiu Mdm frdng (0,88*0,25 mg/kg vdo miia raua vi 0.11*
0,06 mg/kg vio mua kho) (Huih 2). Cdc kit qud nay cho thiy hira lugng N-NOj" frong ddt d cic diera ngfailn ciiu o mice rdt tfadp, chi cd hdm lugng N-NO3" d diim nghiin ciiu Vet tdch vdo raiia mua la dgt miic thdp (Tran Van Chinfa et al, 2010).
Drficdoi V?t tach 27,76°C*0,05 vao miia khd), tiep den la d diem nghiin ciiu Duoc ddi (27,24^*0,05 vio raua raua vi 27,78°C±0.04 vdo mua kfad) vd cao nhdt Id d diem nghien ciiu Vet tach (27,30°C *0,00 vdo miia raua va 27,84''C±0,05 vao raiia kho). Nhilt dp nudc d cdc diem nghien ciiu vao cd miia mua vi miia khd nhin chung deu thuan lgi cho qua frinh amdn hda sdn sinh NH4^ xay ra.
3.2.2 pHnudc
Kit qui d Hinh 3 cho thdy pH nudc do dugc d diem nghiin ciiu Vet tich (7,21*0,08 vao miia mua va 7,38*0,08 vdo miia khd) khdng kfaac biet cd y nghia thong ke so vdi diem nghien ciiu Dude ddi (7.16*0,05 vio raiia raua va 7.28*0.08 vao mtia khd) (p>0,05) nhung Igi khac bilt co y nghia thong kl so vdi diim nghien ciiu Mam frang (7,02*0,09 viomiiamua va7,l7±0,08 vaomiiakhd) (/7<0,05).
pH nudc d cac diim nghien ciiu nhin chung diu thudn Igi cho cho sy phat frien eila vi khudn nifrate hoa vd sy hiln diln ciia NHj* frong mdi trudng.
Tgp chi Klioa bgc Tnr&ng Dgi hgc Cdn Tba Khoa hoc Tu nhiin. Cong nghe vd .Mdi truang. 29 (2013): 37.44
• Miia mua 0 Mua kho
Hinfa 3: pH nirdc d cic diem nghiin eihi Ghi chu: Cdc gid tri a cdc col co ciing I chir cdi (.4. B, C hay a, b, c) thi khong khdc biel cdy nghia thing ki(p> 0.05)
3 2.3 Hdm lugng oxy hoa tan trong nudc Kit qud nghiin cim d Hinfa 4 cho thiy ham lugng oxy hoa tan (DO) trong nudc d cdc diim
Diroc doi Vet tach nghien ciiu vao miia mua khdng khac bi?t c6 y nghia thing kl (p>0,05) nfaung lgi khic bilt co y nghta thing kl vdo miia khd (/7<0,05).
Hinh 4: Him lugng DO trong mrdc if cdc diem ngfaien cuu Ghi chu: Cdc gid tri a cdc egt cd cimg I chir cdi (A. B, C hay a. b, c) ihi khdng khac biet coy nghia thing ke (p>0.05)
3 5 3,0 2.5 2 0 1.5 - 1.0 0.5
• Mua mira 0 Miia kho
Mam trang Him lupng DO d diira nghien ciru Vet tich la 2,87 mg/L±0,09 vdo miia mua va 3,42*0,02 mg/L vao mua khd. d diira ngfailn ciru Dude ddi Ii 2,82 mg/L*0,07 vio miia mua vd 3,31 mg/L±
0.06 vdo miia khd va d diera nghien ciiu Mam trang la 2,78 rag/L*0,ll vio miia raua va 3.22 nig/L±0.05 vdo miia kfad. Nfain cfaung. him lugng DO d cac diem nghien ciiu vio ed miia mua va raiia kho diu thuin Igi cho qua trinh nitrate hda frong moi fruong nudc xiy ra.
3.2.4 Dg mgn nudc
Theo khio sat d Bing 9 cho thay dp man nudc cd gii frj thip nhat o diim nghien ciiu Mira trang (19.30%o±0.00 vao miia mua %a 29.12%o±0.04 vao
miia khd). tiep den Ii d diem nghiin ciiu Dude doi (19,34%o*0,05 vao miia mua va 29,20%o*0,07 vao miia kho) vi cao nhit li d diim nghien ciiu Vet tich (19,40%o±0,00 vao raiia mua va 29,26%o
*0.05 vdo miia kho).
Bang 9: Dd man nird-c (%o) d cdc diem nghiin clhi
Mdm trdng Piro'c ddi Vet tdch Miia mua
Miia khd
19,30*0,00'' 19,34*0,05" 19.40*0,00' 29.12*0.04^ 29.20*0,07" 29.26*0,05^
Ghi chii Cdc gid tri d ciing mgt hdng co citng chir cai (a. b. c....) thi khong khdc biel coy nghia thong ke (p>0.05)
Tap chi Khoa bgc Tnr&ng Dgi hgc Can Tha PhdnA: Khoahgc Tunhien. Cdngngh^ va Moi tnr&ng. 29 12013)- 37-44 3.2.5 Hdm luang N-NH4 trong nudc
Kit qud nghien ciiu d Bang 10 cho thay him lugng N-NH4* frong nudc d diira nghiin cihi Dude ddi cd gia frj la 0,360 mg/L*0,026 vio raiia mua va 0,176 mg/L*0,012 vio mua kho. Tgi diem ngfailn eiiu Mira frang gid tri ghi nfadn Ii 0.344 mg/L*0,036 vdo raiia mua vi 0,165 mg/L
*0,0I7 vio miia kho vi d diira ngfailn ciiu Vet tach Id 0,318 mg/L±0,025 vdo miia mua vi 0,149 rag/L±0.012 vao miia khd. Tuy nhien, ham lugng ammdn dgc biet vdo miia mua Igi cao hon miia khd. dieu nay cd the do sy boa lan dgm tir cac vdt ryng da bi phdn hiiy frong mua khd Idra thinh phan niy hiln dien cao d trong mdi trudng nudc.
Bdng 10: Ham lugng N-NH4^ trong nudc (mg/L)
& cac diem nghien ciru
Mam trSng Pudc doi Vet tach Miia mua 0,344*0,036=0,360*0,026" 0,318*0,025' Miiakfad 0,165*0.017"" 0,176*0.016'' 0,149*0,012'^
Ghi chir Cdc gid trj a ciing mot hdng cd cung chu cdi (a. b, c....) thi khdng khdc biel cd y nghia thong ke (p>0.05)
3.2.6 Hdm lugng N-NOf trong nudc Qua hai dgt khao sat d Bang 11 cho thdy hdm lugng N-NO3" frong nudc vio miia raua d diem nghiin ciiu Duoc ddi la 0,053 mg/L*0,005 , 6 diem nghiin ciiu Vet lich Ii 0,049mg/L*0,008 va d diem nghiin ciru Mdm tring Id 0,042 mg/L*0,007.
Bdng 11: Ham lugng N-NO3' trong nirdc (mg/L) d cac diem ngfaien ciru
Mam trang Duoc doi Vet tach Miia mua 0,042*0,007" 0,053*0.005" 0,049*0,008"
Miia khd 0.011*0,003" 0,018*0,001" 0,022*0,004"
Ghi chii: Cdc gid tn a cimg mgt hdng co cimg chir cdi (a. b, c....) ihi khdng khdc biel COy nghia thdng ke (p>O.OS)
Vdo miia khd, hdm lugng N-NO3" frong nudc cao nhat d diim nghien ciiu Vet tich vdi gid fri la 0.022 rag/L*0,004 , tilp din li 6 diim nghien ciiu Dude ddi vdi gii frj Id 0,018 mg/L*0,001 vi tfaip nhit d diim nghiin ciiu Mam trine vdi gii frj Id 0,011 mg/L*0,003 . Kit qui cho thiy nifrat khdng khdng khdc bilt dang kl o cic khu vyc phan bo Mim. Dude vd Vet. Tuy nfailn hdm lugng nitrat dac bilt vao miia mua lai cao hon miia khd, dieu nay cd thi do sy hod tan dam tir cdc vdl ryng dd bi phdn hiiy frong miia khd lam thanh phdn nay hien dien cao d frong mdi frudng nudc. Tuang ty nhu d kit qud dgm amradn, dgm nitrate ciing cd xu hudng
cao frong mua raua cd tfal do cimg nguyin nhan nhu da thdo luan d fren.
4 KET LU^N VA » E XUAT 4.1 Kit lugn
Diem nghien ciiu Mam trang cd sd ngdy va sd lin ngdp trieu cao nhat (334 ngay/nam vd 502 lin/ndm) vd thdp nhat la d diem ngfailn ciiu Vet ticfa (72 ngay/ndm va 73 lin/nam).
Cic ylu td radi trudng nhu nfaiet dp, pH va DO diu CO liln quan din sy cung cdp dam va dac bilt li cic thinh phin dam vd co frong dat.
Dam long trong dit cd gii fri cao d diim nghien ciiu Dude ddi vao ci 2 raiia khd vd mua. Diera nghiin ciiu Vet tdch cd gia tri dam tong thip nhit kl ed frong 2 miia. Tuong ty dam tdng, him lugng N-NHi" frong dat cao d diira nghiin ciru Dude ddi.
Ham lugng N-NH4* vi N-NO3" frong nudc tai tat ca cic khu vyc ca 3 loai phan bd cd gid fri vao miia mua cao hon so vdi miia kfad.
Ham lupng dgm tdng trong Id cay Mam frang cd gid fri cao nhdt (1.79% ddi vdi la xanh. 1,34%
ddi vdi Id vang va 1,16% doi vdi la nau), tilp din li la cay Vet tach (1.06% ddi vdi Id xanh, 0.63%
doi vdi Id vang vd 0,50% doi vdi la nau) va thip nhdt la la cay Dude doi (1,03% ddi vdi Id xanh, 0,54% ddi vdi la ving va 0,41 % ddi vol Id ndu).
4.2 De xuat
Nghiin ciiu sy phdn hiiy Id vd vdt rung ciia Mdm, Duoc vd Vet de danh gia vai trd ciia la rimg frong viec cimg cap va tuin hoin dinh dudng.
TAI LIEU THAM KHAO 1 Alongi, D.M., K.G, Boto and A.I.
Robertson. 1992. Nitrogen and Phosphorous Cycles. In Tropical Mangrove Ecosystems (Eds. Robertson, A.I. and D.M. Alongi).
American Geophysical Union, Washington, DC, pp. 251-292.
2. Ng,d Ngpc Hung, 2004. Gido trinh thuc tap tho nhudng. Truang Dgi hpc Can Tha. Luu hdnh ndi bd.
3. Nguyen Thi Hdng Hanh va Mai Sy Tuin, 2005. Sy tich ty cacbon va nito trong miu phdn hiiy lupng rai va frong dit rimg ngap mdn fauyin Giao Thiiy. tinh Nam Djnh. Hgi thdo todn qudc ve vai trd cua he sinh thdi rirng nggp man vd ran san hd trong viic gidm nhe tdc ddng cua dai duang din mdi trudng, HaNoi, trang 271-276.
Tap chi Kboa bgc Tnrang Dai boc Cdn Tho Ph&n A - Khoa hgc Tu nhien. Cong nghi vd Moi tnr&ng, 29 (2013): 37-14 Phan Nguyin Hong (Chii bien). 1999. Rung
nggp mdn Viet Nam. Nha xuat ban Ndng nghiep, Hd Npi. 197 frang.
Trdn Vin Chinh (Chii biln), Cao Viet Ha, Dd Nguyin Hai. Hoang Vdn Miia. Nguyen Hihi Thdnh va Nguyin Xudn Thanh, 2010.
Gido trinh Thd nhudng hoc. Tnrdng Dai hpc Ndng nghiep I, Ha Ndi.
6. Vazquez, P., G. Holguin, M.E. Puente, A.
Lopez-Cortes and Y. Bashan, 2000.
Phosphate-solubilizing microorganisms associated with the rfaizosphere of mangroves in a semiarid coastal lagoon.
Biol Fend Soils 30:460-468.
7. Wilkinson, C. and V. Baker, 1997. Survey Manual For Tropical Marine Resources.
Australian Institute Of Marine Science, Townsville.
