JOURNAL OF SCIENCE OF HNUE DOI: 10.18173/2354-1059 2017-0023 Natural Sci 2017, Vol. 62, No, 3, pp, 191-198
This paper is available online at htlp,//sldb.hnue.edu.vn
P H A N T I C H QUAN HE G I U A BIEN D O N G SU DUNG D A T VA BIEN DOI C U A M O T S O YEU T O K H I HAU, T H I E N T A I TAI T I N H HA T I N H
P h a m Vu C h u n g
Khoa Dta li - Qudn M Tdi nguyen. Truang Dgi hge Vinh Tom tat. Bien doi khi hau gia lang tan suit, cudng do han han, ngap lul, hoang mac hoa.,, la mpt trong nhimg nguyen nhan quan trong gay bien dpng dai san xudt nong nghiep lai tmh Ha TTnh. E)e phan tich anh hudng cua mot so cae y6u l6 khi hau va ihien lai d6n bi^n dong sfl dung dat nong nghiep a tiiih Ha TTnh Irong giai doan 2005 - 2015 chung l6i da su dung mo hinh hoi quy logistic da bien nham xac djnh luong quan gifla su bien dong su dung dii nong nghiep vdi su thay doi ciia mdl so yeu lo khf hau va Ihien lai. KH qua tfnh loan cho thSy;
Bien dong sfl dung dat co lucmg quan thu^n vdi su thay doi cua nhiet do.mflc do kho han, ngap lut, thoai hoa dat va co tuong quan nghjch vdi sy thay doi cua Mong mua nam, trong do ngip lut CO tac dgng thuan ldn nhat den bien dpng six dyng dai.
Tir khda: Bien dpng su dung dai, bien dfli khf h^u, cac ySu Id khf hau, thien tat, mo hinh hfli quy logistic. Ha TTnh
1. Mo-dau
Sfl dyng dat, d i e biet dat ndng nghiep lgi Ha TTnh trong thdi gian gin day cd nhieu bien dpng.
Cd nhieu nguyen nhan gay bien ddng sfl dung dat (BDSDD) va mdt trong nhung nguyen nhan quan quan trgng la do t i c ddng cua bien ddi khi hau (BDKH) va tliien tai. Sd lieu thuc te cho thiy:
Trong giai dogn 2005 - 2015 sy thay ddi cua nhiet do, lugng mua va sy gia tang tan suit, cudng dp cua nan^ ndng, mua Idn da lam gia tang ngap lut. han han, hoang mac hda... lam cho nhieu dien tich dat ndng nghiep n h u dat lua, d i t hoa mau, dat nudi trdng thuy san... khdng the san xual dugc v i budc phai chuyen ddi sang mue dich sfl dung k h i c hoac bo hoang hda [1]. Tuy nhien, viec dinh gia djnh lugng nhung tac ddng nay ggp nhieu khd khan, ddi hdi chudi sd lieu ve ddt tuong g i y t i e ddng v i ddi tuprng bi t i c dpng phii cd du dp dai thdng ke Trong trudng hgp cu the d linh Ha TTMi, do khdng cd eac chudi sd lieu thdng ke du dii chung ldi da chpn each tiep can danh gia djnh linh, thdng qua viee phan lieh mdi tuang quan/quan he gifla BDSDD va su Ihay ddi eua mdl sd ydu id khi hau va hien tugng thien tai trong xu the BDKH trong giai doan 2005 - 2015 lai tinh Ha 'Tinh bang md hinh hdi quy logistic da bien.
2. Ngi dung nghien cmi
2.1. Phuang phap nghien cuii va nguon so lieu 2.1.1. Phan tich h^i quy logistic da bien
De phan lich i n h hudng cfla mdl sd yeu Id klii hau va Ihien laj den BDSDD a tmh H i TTnh trong giai doan 2005 - 2015, t i e gia da su dung phuang p h i p hdi quy logistic da bien Ngaynhan bii 11/11/2016 Ngay nhan dang 12/1 2017
Tic gia lien he: Pham Vii Chung, e-mail: [email protected] .com
Ph^m Vii Chung
Phuang phap phan lich hdi quy Binary Logistic li mdl kl thuit thdng ke sfl dung bien phu thudc dang nhi phan de udc lugng xac suat mdt sy kien se xiy ra vdi nhflng thdng tin efla bien dpc lap ma la cd duac. Phan tich hdi quy cd uu diem la the hien mdi lien he gifla cic yeu td bang mot phutrng trinh hdi quy. Cae he sd hot quy la mpt trong nhflng biSu Men cfla mdi lien he giua eac yeu Id nghien eflu Tien hinh phan lich hdi quy logistic da Men bing phin mem SPSS.20 de xae dinh mdl tuang quan gifla cac yeu Id kM hau ddi vdi BDSDD. Md Mnh ham hdi quy logistic da bi&i ed dgng:
„Bo + B,.X] +B2.X2+ • + Bn.Xn
P ( Y = 1 ) = ^ g ^ ^ g^ jj^ ^ g^ jj^ ^ ^ g^ j j ^ j [ j
Hoac cd the viet dudi dgng:
f(y=i)\
CY=0)j : Bo+BiXi -I- B2X2 +••• -H BnXn
trong do: XI, X2,...., Xn- Cac bien ddc lip; Bl, B2,..., Bn: Hesd hdi quy cfla cic bien ddc lap.
He sd B phin inh lupng bien tMen cua Y kM mgt dan vi X thay ddi (khi bien X, thay ddi mpt dan Vl va cac bifin sd khic khdng fliay doi thi Y thay ddi B, dan vi); BO: Hing sd; P(Y=1) = PO: la xac suit xiy ra BDSDD; P (Y=0) = 1 - P (Y-1): la xic suit khdng xiy ra BDSDD.
Dd phu hpp tdng the cfla md hinh dugc danh gia dya vao chi tieu -2LL (-21og likelihood).
Gia tri -2LL cang nhd the hien do phfl hgp cao. Dgi lugng Wald x2 duge sfl dung de kiem djnh y nghia thong ke cfla he sd hdi quy tdng the.
Kiem dinh Wald (kiem dinh gii thuyet hdi quy khac khdng). Neu he sd hdi quy B deu bang 0 thi ti le chenh lech gifla cac xac suit se bang 1, tflc xic suit de sy kien xay ra hay khdng xiy ra nhu nhau, luc dd md hinh hdi quy khdng cd lac dung dy doan. Dai lugng Wald x2 dugc tinh dieo cdng thuc:
trong dd: B la he sd cua md Mnh hdi quy, s.e (B) la sai sd chuan cfla h? sd hoi quy B.
Vdi do tin ciy 95%, cac bidn doe lap dugc coi li cd y ngMa va cd luang quan vtii BDSDD khi gia tn P- value (Sig) <0,05 = 5%.
Hp so xac dinh R^ dugc djnh nghta nhu la ti lp (hogc %) cua sy bien dpng cua bien phu thugc Y dugc giii diich bdi cac bien dde lap Xj. (0 < R^ < I vdi R^ = 0 the hi?n X va Y dpc lap Ihdng ke, R = 1 the Men X vi Y phy thudc luyen tinh hoan hio) [1, 3].
Tnrdc kM dua gii trj cac bi8n vao md Mnh hoi quy, cac bi6n dugc kiSm tra Men tugng da cpng tuyen. Dd la trang thai cae bien ddc lap cd mdi luong quan Men hfln vdi nhau trong mo Mnh.
Da cgng tuyin lam sat lech hoac ddi dau cac hp so hdi quy yong phuang Irinh hdi quy kMen cho cac he sd cfla md Mnh kem y ngMa hon.
De loai bd hien lugng da cdng tuyen each don gian nhat la logi bd bien cd dau hieu cgng tuyen cao ra khdi md hlnh. De kiem tra Men lugng da cdng tuyen cd the dflng he sd phdng dai phuang sai (VIF) nham xae dinh diu hieu efla da cdng tuyen. He sd VIF dugc linh theo cdng thflc:
™ = T ^ (4) trong do: R^k la he sd tuang quan bdi cfla bien thu k trong md Mnh,
He sd phdng dgi phuang sai VIF cfla cac bidn cang ldn chflng Id cpng Uiydn cao. N6u VIF cua mdt bidn vucrt qua 10 tM biea dd duac coi la cdng tuySn cao, vi vay cin phai loai ra khdi mo Mnh [1, 3].
Phdn tich quan hf gida hien dpng su dung ddt vd biin doi cua mpi so yeu i6 khi hdu. thien ti
2.1.2. Dir lieu dau vao
P h u a n g trirfli hdi quy logistic the Men mdi quan he hdi quy gifla b i i n phu thudc va cac hien dpc lgp. Bien phu thudc la BDSDD v i cac bien ddc lap bao gdm: bien nMet dp trung binh nam;
lupng m u a trung binh n i m ; mflc dg khd han; mflc do thoai hda dat tidm nang; muc dp n g ^ lyt tinh Ha TTnh.
Gia tri e i c bien dugc trich xuat tfl cae ban do do t i c g i i xay dung hoac dugc k£ thua va bien tip lai, cu the:
- Biin nhiet dp tmng blnh nam: Dya tren ngudn sd lieu thu thap tfl tram KM tugng - Thfly van B i c Trung bd, gdm sd lieu nhiet dp trung bmh t h i n g va nam trong vdng 35 nam (tfl 1980 - 2014) cua 4 tram H u a n g Khe, Kim Cuang, Ha TTnh va Ky Anh da sfl dyng phirong phap ndi suy yong GIS de thanh lap ban dd p h i n bo tfliiel do trung binh nam cho tinh Ha Tinh, ti le 1/100.000.
Tren b i n dd phan hda cac dudng d i n g nhiel each nhau 2"C.
- Bien lugng mua ndm: Tac g i i da kd thfla ban do p h i n bd lugng mua n i m , ti le 1/100.000 vung B i c Trung bd cua dk lii KHCN-BDKH/11-15 [4], dugc dianh lap dua tren chuoi s6 lieu long lugng mua trung binh t h i n g va nam giai doan 1980 - 2014 cua 14 tram do mira tren lanh thd Ha TTnh.
- Biin h}n hdn: ki thfla ban dd mflc dp khd hgn, ti le 1/100 000 ciia d^ tai KHCN-BDKH/11-15 [4].
Hien irang mflc dp khd han cfla tinh Ha TTnh dugc danh gia ihdng qua chi so khd hgn (sd thing ed tan suat han > 30%).
- Bien thodi hda ddi tiim nang: Ke thfla ban dd Thoii hda dat tiem nang tinh Ha TTnh, li le 100.000 [5],
- Biin nggp lul. ke thua tfl ban d o ngap lul tinh H i TTnh [4] B i n do nggp lyt dugc xay dyng dya tren bin do nen dta Mnh ti le 1:100,000 vdi co sd dfl lieu dau v i o la Irgn Ifl lich sfl tren sdng Lam vao t h i n g 10 nam 2010. Do vgy, tuang quan giua bien n g i p lyt v i bien ddng sfl dyng dat chi dugc xem xel lgi vflng xay ra ngap lyt theo ban dd nggp lyt.
Bdn do Phdn bo nhiet dp trung binh ndm ttnh Hd Tinh
Bdn dd Muc dp khd hgn linh Hd Tinh
Bdn do Thodi hda ddt tiem ndng tinh Hd Ttnh
Pham Vu Chung
Ban dd Nggp lut tinh Hd Ttnh Bdn do BDSDD giai dogn 2005-2015 Hinh 1. Bdn do cdc bien trong md hinh hoi quy Logistic da biin 2.2. Ket qua va thao lu^n
2.2.1. Thilt l^p ca sd dir lieu dau vao ciia mo hinh hoi quy - Phdn cdp vd md hda dU- lieu
Do cac bien ddc lap deu cd nMeu gii tri bien tMen nen cac bien da duge phan cap Ihanh eic nhdm gia trj de vipc phan lich cic dai lugng dugc ro rang han. Gia Iri cua cac bien ddc lap cd the dugc chia thanh n cap (1, 2, 3... n) tfly thupc vao mue dp bien thien gia Iri eua eac bien. Sau khi phin cip, gia tri cua cac bien da dugc ma hda Iheo yeu cau cua md Mnh hdi quy.
Ddi vdi bien phu thupc dupc ma hda thanh gii tri nhi phan 0 va 1, trong dd gia tri 1 tflc la co xay ra bien ddng va gia tri 0 la khdng xiy ra bien ddng.
Kit qua phan cap gia tri va ma hda cac bien dugc the Men trong Bang 1.
Bdng 1. Phan cap vd md hda cdc bien dgc lap dug^c lira chgn trong md hinh hdi quy Bi^n
Nhi?t dp TB nam (°C) Luong mua TB nam (mm) Mirc dp kho han (cap dp) Thoai hoa dat (cap dp) Ngap iyt (m)
1
<18
<2000 Nhe Nhe
>0-l
Cap gia tri ciia cac bien dpc lap 2
18-20 2000-2400 Trung binh Trung binh
1-2 3 20-22 2400-2800
Ning Manh 2-3
4 22-24 2800-3200
>3 5
>24
>3200
- Chgn mdu gid tri cdc bien
Gia tri cac bien dugc xac dinh theo cac mau. Bang cdng cu lay mau trong phan mem Arc GIS da lira chpn ngau nhien 5.000 diem mau, mdi diem tuang iing mgi pixel sd lieu. Trong cac diem mau cd 2.744 diem mau dupc lya chpn tren cac klioanh vi dat ndng nghiep ed bien ddng: dit lua chuyen sang dat cay hang nam, dat lfla sang cay lau nam, lua sang nudi trdng thfly sin, lua sang dat hoang hda. dat cay hang nam sang dat lua, cay hang nam sang dat ciy lau nam, cay hang nam sang dat rung ^ n xual, cay hang nam sang dat nudi irong thfly san. cay hang nam sang dit hoang hda, dat cay lau nam sang rung sin xuit, cay lau nam sang dat hoang hda, dit nudi trdng thuy sin sang dat sdng sudi va mat nudc chuyen dung vi 2 256 dilm miu duge lua chpn tren eic khoanh vi d^ trdng lfla, dit trdng eay hang nam. dit trdng cay lau nam, dat nudi ydng thfly sin khdng biln ddng.
- Kiem tra hipn tuang da cpng tuyin
Tnrdc kM dua cic biln vao md Mnh hoi quy, cac bien can dugc kiem tra Men tupng da cdng tuyin. Kit qua kilm tra da edng tayin bing phin mem SPSS the hien trong Bang 2.
Phdn lich quan he giira bien dpng su dung ddt vd bien doi cUa mgt sd yeu to khi hdu. thien tai...
He sd [)hdng dai phuang sai VIF cua cic bien deu nhd han 10 (Bang 3), chung td Men tuang da cpng tuyen khdng anh hudng den md Mnh, vi vay cac bien dugc chap nhin de dua vio md hlnh hdi quy.
Bdng 2. Kit qud kiim tra da cpng tuyen stt
1 2 3 4 5
Ten bien Nhiet dp TB nam Luang mua TB nam Muc dp khp han Thoai hoa dat tiem nang Ngap lut
Ki hilu bien NHIETDO LUONGMUA KHOHAN THOAIHOA NGAPLUT
He so phong dai phirong sai (VIF)
1,148 1,177 1,145 1,053 1,147 2.2.2. Tinh toan cac thdng so cua cac bien
Tien hinh hdi quy limg budc theo phuang phap Enter. Tit ci cic biln dugc dua vio md hinh hdi quy sau dd dugc tuin tu loai tru bang tieu chuan loai trfl POUT Biln dugc giu lai trong md hinh kM gii Iri F (gia tri linh loan trung gian trong md hinh) khdng vugt qua gia tri POUT, dugc mac dinh bing 0,1. Md Mnh se dflng lai kM udc lupng tham so nhd hon 0,001.
Kit qua chay md Mnh cho thay: Gii in -2LL (-2 log likelihood) = 5428,391" la khdng ldn lam, chflng id md Mnh long the cd dd phfl hgp kha ldt.
He sd xac dinh R^ = 0,338 ndi len ti le phin bten ddng cfla su dyng dat dugc giii thich tu cac Men nhiet dp, lugng mua, khd hgn, thoai hda, ngap lut la 33,8%.
Gii tn cua cac bien trong md Mnh the Men d Bang 4.
Bdng 4. Gid tri cdc thdng sd cua cdc biin
Bien (1) NHIETDO LUONGMUA KHOHAN THOAIHOA NGAPLUT Cpnstant (Bo)
He so hoi quy (B) (2) 0,195 -0,204 0,980 0.367 1,044 -3,421
Sai so chuan (S.E)
(3) 0,050 0,031 0,053 0,034 0,055 0,229
Wald
(4) 15,361 43,122 336,358 113,526 361,028 222,636
Sig.
(p-value) (6) 0,000 0,000 0,000 0,000 0,000 0,000
Exp (B) (7) 1,216 0,815 2,664 1,443 2,842 0,033 a = 0.05: R' = 0,338: -2LL = 5428.391"
Kit qui chay md Mnh hdi quy duge the Men d Bang 4 cho thiygii tri sig efla tat ea cae bien deu < 0,05, cd nghTa li tat ci cic bien ddc lap deu ed anh hudng den BDSDD giai dogn 2005 -2015'. He sd hdi quy B cua bien lupng mua mang diu am, cd ngMa la luong mua cd tuang quan nghich vdi BDSDD; he sd hdi quy B cfla cac bien: nMet dp, han han, thoai hda, nggp lut deu cd dau duang, the hien cd tuang quan thuan vdi BDSDD.
Vdi he sd B xac dinh dugc, phuang hinh hoi quy cd dgng:
log (pl/pO) = -3,421 + 0,195.NHIETDO - 0,204.LUONGMUA + 0,980 KHOHAN + 0,3 67. THOAIHOA + 1,044.NGAPLUT
Pham Vu Chung
2.2.3. Phan tich anh hudng ciia cac ylu t6 khi h^u den biln d$ng su- d^ng dat tinh Ha Tfnh
^ a i do^n 2005 - 201S
Kit qua chay md hinh hoi quy logistic di dua ra dupe moi tuang quan giua eac yeu td kM hiu va BDSDD thdng qua he sd hdi quy giihi cic bien dpc lgp va hiln phu thudc.
Tfl ket qua tinh loan nhgn dugc, tic gii da budc diu dinh gia ve tuang quan giua BDSDD vdi su bien ddi cfla cac yeu to khi hau va thien tai. Tuang quan nay dugc tinh theo cdng thuc (5), the Men sd lan thay ddi efla bien sfl dung dat theo su thay ddi cic cip cua biln dpc lap.
e^° + e^' (5) trong dd: BO-Hangsd =-3,421; Bi-Hesd hdi quy cfla cac biln ddc lap
- Tucmg quan giira nhipt dp v&i BDSDD- He sd hdi quy cua bien nhiet dp li 0,405, the hien yeu td nMpt do cd tic dpng thu|n vdi BDSDD. Cd nghta la nMet dp trung binh nam cang tang thi xac suat BDSDD xay ra cang manh. Ket qua linh loan theo cdng Ihuc (1) cho ihiy: Neu nMet dp tang len 1 cap (2 "C) vdi di&i ki?n eic bien khac gifl nguyen gia In tM xic xuil xay ra BDSDD la 1,50 lin.
Ket qui phan tich sd lieu kM hgu Ha TTnh cho thay: Trong giai doan 2005 - 2015 nMet dp d Hi TTnh tang len cM khoing 0,2 "C nen BDSDD do tic ddng cua nhiet dp chi xay ra khoang 0,15 lin. Nhu vgy, tic dpng cua nM?t dp den BDSDD Ihdi gian qua khdng ldn.
- Tirang quan giira lu^g mua v&i BDSDD: he sd hdi quy cfla bien lupng mua bang -0,204, the Men lugng mua cd tuong quan nghich vdi BDSDD. Kel qua tinh loan theo cdng thuc (1) cho thay: neu lugng mua giam mgt cap (400mm) va cac bien khac khdng thay ddi thi xic suit xiy ra BDSDD sg ting len 0,82 lan. Dieu niy khi phu hsjp vai Ihuc le vi Ha TTnh la linh cd lupng mua trung binh nam len tdi 2000mm nen anh hudng cfla lugng mua trung binh nam din BDSDD khdng ldn.
- Tuang quan giiia muc dp khd hgn v&i BDSDD: he sd hdi quy cfla bien muc dp khd hgn kha cao, bing 0,98 the Men mue do khd hgn cd tuong quan thuan vdi BDSDD, nghia la: muc dp khd han cang ting tM khi ning xay ra BDSDD cang ldn. Ket qua linh loan dieo cdng thuc (1) cho thay: xac suat xay ra BDSDD se tang 2,66 lan neu mue dp khd han ling len mpt cip. Dieu nay cho thiy, ylu td khd hgn ed anh hudng rit mgnh den BDSDD. Cd the ly giii vin dl nay nhu sau-
Thdi gian qua, dudi tic dgng cua BDKH, nhipt dp tai linh Ha TTnh cd xu thi lang cao kem theo gid Lao khd ndng hoat dgng mgnh han, keo dai (tu thing 3 - 7), mua il di, lupng nudc bdc hoi ldn lam cho dat dai bi khd cin. Nhung nai hgn hin trudc day chi keo dai khoang 2 - 3 thing nay da tang len 4-5 thing, thgm cM cdn keo dai 6 thing (tfl thing 3 den thing 8) [6]. Hgn hin lam dat dai khd can, cay trdng tMeu nude ngMem trpng. dan den nhieu dien tich cay trdng bi chit hogc mit tring. Thyc tl nay da gap tgi mgt sd nai ihugc cic huyen Ldc Ha. Thacli Hi. Ky Anh, Huong Khe.
Theo ban do phan vung muc dp klid hgn linh Ha TTnh, thupc vflng hgn ngng va hgn trung binh bao g6m hau hit cac huy?n vflng dong bing ven bien va trung du. Dilu do eho thiy, logi dat chiu anh hudng manh nhat cfla han han la dit sin xuit ndng nghiep (dit lua, dit yong ciy hang nam va dat trong cay lau nam).
Dit trong lfla tinh Ha TTnh giai doan 2005 - 2015 bien dgng giam 7.243,60 ha. Trong dd. theo ngMen cuu cd mgt phan dien tich dat lua do cMu tie ddng cua dieu kien kho hgn khdng chfl ddng dugc ngudn nudc, nang suit Ihap nen da dugc ngudi dan chfl dpng chuyen sang trong cac logi ciy hang nam nhu diu, khoai lang. ngd.... Mdt sd dipn tich dat lfla vflng cao do khd hgn, diln Mnh tgi cac huyen Due Thp (gdm cac x3 Tung Anh, Due Dung...); huyen Ky Anh (KyTay, Ky Phong, Ky Bac, Ky Xuan..,). huyen Cam Xuyen (Cam Quan, Cim Lac.) dugc chuyen sang dat trdng cay lau nam nhu cam, budi....
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Phdn lich quan h^ giira bien dpng su dung ddt vd bien doi cua mpi sd yeu to khi hdu. thien tai...
Dat trdng c^y hang nam trong giai dogn bien ddng giim la 3.271,30 ha. Trong do, so dien lich han hin vung gd ddi dugc chuyen sang dii trdng cay lau nam, mpt sd khac chuyen qua dat lam ngMep do dat bi thoai hda, dien hinh nhu d cac xa Ky Tay, Ky Tan, Ky Ddng (Ky Anh); Lpc Yen, Phuang My, Ha Linh, Hoi Hai (Huang Khe); Huang Thp (Vu Quang); Cam Quan, Cam Trung, Cim Son (Cim Xuyen)...
Mdt sd dien tich dit trdng ciy hing nam do nang ndng va khd han khdng canh tac dugc phai bd hoang, dien hinh mdl sd dia phuang nhu: Xuan LTnh (NgM Xuin); Thgch Dinh. Bic San (huyen Thach Ha); Ky San, Ky Tay, Ky Phong, Ky Tiln (Ky Anh); Huong Lien, Phuang MJ (Huong Khe); Cim Duang (Cam Xuyen); Dflc Dung (Due Thp); San Kim, Scm Hong (Huong Son).
Hien tuong klid hgn pliit trien tren dien rdng va keo dii cflng dan den kha nang thieu nude cho nudi trdng thfly sin nude ngoi va dp man tang cao ddi vdi thfly sin nudc lg kMin mdt sd dien lich vao mua khd khdng nudi trdng thfly sin phii bo hoang, diln Mnh lgi cae dia phirong nhu: xa Thach Trj, Thgch Ban. Thach Van (Thach Ha); xa Hp Dp (Ldc Hi); xa K.-^ Hi (Ky Anh) [6].
Mat khac, BDKH lim cho tinh trang ning ndng vi hgn han keo dii, myc nudc d cic con sdng xudng thip tao dieu kipn cho sy xam nhap man tien sau vao dit lien anh hudng true tiep cae vflng sin xuil ndng nghiep, nhat la eac khu vuc canh tac lua nudc.
- Tucmg quan giiia thodi hoa ddt tiim ndng v&i BDSDD: he sd hoi quy cfla bien thoai hda dat bing 0.367. Kel qui linh loan theo cdng diuc (1) cho diiy: neu muc dp thoai hda lang len mdt mflc iM kha nang xay ra BDSDD tang 1,44 lin. Nhu viy, yeu id thoai hda dat cd anh hudng tuang doi manh den BDSDD. Mat khic, thoai hda dit la he qui tic ddng cua mpt loat cac ylu to ty nhien nhu khi hau, dia hinh. do ddc. log) dat ting day dit. tham thyc vit vi con ngudi. do vgy thoil hda dit tiem nang ehi mang tinh tham chieu de danh gii BDSDD va chung tdi khdng cho li nguyen nhan tryc tiep gay bien dpng su dung dat tai linh Ha TTnh.
- Tuang quan giira nggp lut v&i BDSDD: he sd hdi quy cua biln ngap lut bing 1,044, nghia li neu ylu to ngap lyl gia lang len mpt muc dii kha nang bien ddng sfl dyng tgi nhung khu vyc chiu anil hudng cfla ngap lul sS lang len luang flng li 2,84 lin. Dilu nay cho thiy, ylu to nggp lut cd lae dpng rit mgnh den BDSDD. Theo khao sal, nhflng nam gin day Ifl Ml thudng xuyen xiy ra tren dia ban Ha TTnh ma Iran lu nam 2010 la mpt dien hinh. Thuc ll cho thiy: Nhung khu vyc ehiu anh hudng cua Iran Ifl 2010 van li nai Ihudng xuyen chju arih hudng ldn cua lu hang nam.
Tinh trang nay lam cho nhilu dien tich dit canh tac bi mit. dan din dit san xuit ndng nghiep da cd nhflng bien ddng ldn trong thdi gian qua.
3. Ket luan
l-Dinh gii tic dgng cua BDKH din BDSDD tgi tinh Ha TTnh trong giai dogn 2005 - 2015 bing phugng phap phan tich hoi quy logistic da bien thdng qua vipc xic dinh hp sd hdi quy cfla cac biln ddc lap. gdm: nMpt dp trung binh nim, lugng mua trung blMi nam, mflc dp khd hgn, mflc dp dioai hda dat va mflc dp ngap lut vdi biln phy thudc la BDSDD. tfl dd danh gia tuang quan gifla muc dp BDSDD vdi sy thay ddi eua cac biln dpc lip di cho nhflng ket qui phu hgp vdi thuc trang biln ddng dit sin xuit ndng nghiep d Ha TTtdi yong bdi canh BDKH di vi dang dien ra ngay cang manh me.
2-Bing viee phan lieh gii tn va ti'nh chat cua eac he so hot quy cfla cac bien ddc l|p vdi BDSDD da xac dinh duge mflc dp, xu the tirang quan gifla cac bten ddc lgp vdi biln BDSDD. cy thi:
- Trong 5 bien ddc lap cM ed lugng mua trung binh nim cd tuang quan nghich, cac bien cdn lai diu cd tuang quan thuan vdt BDSDD.
- Muc dp ngap lyl cd he sd hdi quy Idn nhil (1.044), Ihl hien li nhan td gay BDSDD manh nhit tai Ha TTnh
Pham Vu Chung
TAI LIEU THAM KHAO
[1] NguySn Quang Dong, Nguyin Thi Minh, 2013. Gido trinh Kinh le luang, Nxb Dai hpc Kinh le Qudc dan. Hi Npi.
[2] Pham Vu Chung, 2015 Ban do biln ddng sfl dyng dit trdng lfla, dat trdng cay hing nam, dit ydng cay lau nam linh Hi TTnh, giai doan 2005 - 2015, li le 1/100.000
[3] Hoang Trpng vi Chu Nguyin Mdng Ngpc, 2008. Phdn tich dii- lieu nghien cuu v&i SPSS, Tip 2, Nxb Hdng Dflc.
[4] Hoang Luu Thu Thfly vi nnk, 2015. Ddnh gid mue dp tdn thuang cup he thdng kinh te xd hpi do tdc dpng cua bien doi khi hgu lgi viing Bdc Trung Bp (thi diem cho tinh Hi Tmh) thugc Chuang trinh KH&CN phuc vy chuang trinh muc lieu qudc gia ung pho vdi bien ddi kM hau. Ma sd: KHCN-BDKH/11-i 5, Ha Npi,
[5] Nguyin Dinh Ky, 2012. DiSu ya danh gia hign trgng nguyen nliin suy thoai lai nguyen mdi trudng dit-nudc vflng Thanh-Nghe-TTnh va de xuil giii phip khai thac quan li long hgp phyc vy phit trien kinh te xa hdi ben vflng.
[6] UBND tinh Ha TTnh, K I hoach hanh ddng flng phd vdi BDKH tinh Ha Tfnh 2011-2015 dinh hudng den nam 2020.
ABSTRACT
Analyze the relationship between land use fluctuations and changes of a number of climatic factors, natural disasters in Ha Tinh province
Pham Vu Chung Department of Geography - Natural Resources Management, Vinh University Climate change increases the frequency and intensity of droughts, floods, desertification and is one oflhe important reasons causing fluctuations in agricultural land in Ha Tinh province. In order lo analyze the impact of a number of cHmaticfactors and natural disasters lo fluctuations in the use of agricultural land in Ha Tinh province in the period of 2005 - 2015, the logistic regression model has been used to determine multivariate correlation between the fluctuations of agricultural land use with the change of climalic factors and natural disasters. Model results showed that land use fluctuations is positively correlated with the change of temperature, drought, flood, land degradation and inversely correlated with changes in annual rainfall in wMch flood that has the greatest effect on land use fluctuatioas.
Keywords: Land use fluctuations, climate change, climatic factors, natural disasters, logistic regression model. Ha Tinh.
