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Chay xay ra tren dien Uch dat san xuat nong nghi?p gky anh hudng Idn den miia mang, cay trdng, vat nuoi, gay thiet hai ve kinh te va tao ra nhung tac dpng Idn d^n nganh nong nghiep. Do vay, vi€c du bao, xay dung ban do phan vung co nguy co chay cao dong vai tro quan trong cho vi^c l|p ke hoach thuc hien quan ly, phong va chua chay, giiip giam thieu rui ro cho san xuat nong nghiep tai dia phuong. Nghien cuu nay ling dung phan mem Maxent (Maximum Entropy), su dung du lieu cac diem chay tir san pham dien tich chay MODIS-Collection 6 MOD64A1 cua NASA trong giai doan tir 2003 din 2016 va cac du lieu GIS va viln tham khac ve cac nhan to anh hudng din chay de xay dung ban do nguy co chay tren dat nong nghidp tai tinh Dien Bien. Kit qua nghien cihi cho thay cac dam chay thudng xuat hien chu y^u vao miia khd (thang 2 vi thang 3). tai cac khu vuc cd do cao tir 500 m din 1.500 m. Oac nhan t6 dang nhiet (bio3) va nhidt dd trung binh cua quy lanh nhat (bioll) c6 vai tro quan trpng nhat den su xuat hien ciia cac dam chay. Ban do phan vimg nguy co chay tr^n diit ndng nghidp cho thay su phan viing ro ret giira cac cap dd nguy co chay khac nhau. Ket qua thong ke cho thay dien tich viing co nguy co chay rat cao la 25.000 ha, vting cd nguy co chay cao la 144.000 ha. vung co nguy co chay trung binh la 73.000 ha va viing cd nguy co chay thap la 33.000 ha.
Kit qua nghien ciiu nay se la co sd quan trong cho ngudi dan va cac nha quan ly ciia dia phuong trong vific dua ra phuong an kl hoach quan ly chay, giam thilu nil do trong san xuat ndng nghidp.
Tir khda: Chay, ndng nghiep, khi hau, vi^n tham, BiSn Bien, Maxent
1 . OAT VAN BE
Trong nhilu nam trd lai day, vai trd cua liia trong viec dinh hinh mdi tnrdng ngay eang dupc quan tam. Nhilu dam chay xay ra hang nam tren the gidi cd Hen quan din eac hoat ddng ndng nghidp nhu dot nuong lam rSy, dot cac vat lieu sau thu hoach nham loai bo ed dai va sau benh hai de phuc vu cho eac vu trong tiep theo (Marco et al., 2020) (Marco, 2020). O cac nude dang phat triln, cac dam chay nay la hien tupng pho biln, day la nguydn nhan chinh dan den su giam chat lupng khdng khi, tang hieu ling nha kinh, ham lirong bui min, khi CO^, CH^ va gay anh hudng din siic khde con ngudi (Hefeng Zhang et al, 2017). Cac dam chay tren khu vuc san xuat ndng nghidp gay thiet hai ve miia mang, anh hudng den ngudn thu cua ngudi dan.
Cimg vdi su phat trien ciia khoa hoc, phat hien chay dua vao anh viln tham da va dang dupc nhieu
' Trudng Dai hoc Lam nghiep -Tnrdng Dai hoc Murdoch. Ausualia
'Trung tam Khuyen nong Qudc gia. 86 Nong nghiep \ PTNT
nha khoa hpc va cac nha quan ly quan tam. Tuy nhien, vdi dac tnmg eac dam chay Idn thudng la chiy rimg, dan den su quan tAm, nd Iue nghidn cihi va quan ly chu ylu tap chung vao chay rimg. Trong khi dd, eac nghien eiiu ve cac dam chay nhd trdn viing canh tae ndng nghidp cdn rat han e h i (Lasko va Vadrevu,2018).
Viet Nam la mdt nude ndng nghidp, phan Idn ngudi dan sdng phu thudc vao cae san pham nong nghidp. cac boat ddng dot nuong lam ray cung nhir ddt cac chat thai ndng nghiep sau thu hoach diln ra thudng xuyen d hau h i t eac tinh, dac bidt la eac tinh miln niii noi ma dien tich dat danh eho ndng nghidp cdn it, ngirdi dan thudng su dung cac didn tich dat gan rimg de trdng cac san pham ndng lam nghifp nhu: Ilia, ngd, san (Social forestry support programme, 2019). Cac hoat ddng dot nuong lam riy, cac chat thai ndng nghiep sau thu hoach la raOt trong nhung nguydn nhan chinh dan din chay rimg d Vidt Nam trong nhieu nam tra lai day (Hoang, 2007). Trong nhiteig nam gdn day. cac nghien ciiuv^
chay d Viet Nam tap hung chu yOu i;i ^^ ^ j ^ ^ ^ ^ ^ (Bao va cs., 2019; Chau, 2012), nhirng nghien ciiu ve chay tren dat ndng nghiep it d u w car nha nghifen
72 NONG NGHIEP VA PHAT TRIEN NONG THON - KY 2 - T H A N G 9/2O20
KHOA HOC CONG NGHl cuu cung nhu cac nha quan ly quan tam. Tir cac han
ch^ kl trSn, da ti^n hanh nghiin cihi xay dung ban do du bao chay trSn dat nong nghiep tai tinh Dien Bi&n nham cung cip nguon tham khao cho cac nha quan ly trong linh vuc quan ly lira mot each hifeu qua.
Xuit phat tir nhimg thuc tiSn ke tren, nghien cijtu nay dmic thuc hien nham gop phjn quan trong trong viec lap ke hoach phong va quan ly lira co hiftu qua a khu vuc nghiSn ciiu nham giam thieu toi da nhOng thiet hai do ch4y gSy n6n.
2. gdi mm u PHUONG PHAP NGHEN COU 2.1. Khu vuc nghita cihi
Nghidn ciru nay dirpc thuc hien o tinh Dien Bien thuSc viing Tay Bac cua Viet Nam (o toa do 20°54'- 22°33'N, 102°10'-103°36'E), co dita tich gan 9540 km' (Hinh 1). DiSn BiSn co khi hSu nhiM doi gio mua mii cao, miia dong lanh kho va miia he nong ^m. Luang mua tmng binh hang nam khoang 2.000 - 2.400 mm tap trung chii yeu vao thang 7 va 8. Miia kho keo dai
tir thang 11 den thang 3 nam sau. Mot nam co 2 - 4 thang kho han. Nhiet do trung binh nam 20 - 23°C.
Nhiet do cao nhat dat toi 41''C va nhiet dd thap nhat CO the xuong - 2"C. Dac bifet hang nam c6 khoang 12 ngay cd suong muoi, 20 -100 ngay suong mil va 20 - 40 ngay co gio kho nong (Van, 2015).
Dien Bien co dien tich dat nong nghiep khoang 11,32% tdng dien tich dat ttr nhita vdi hau het la 6 vimg dong bang. Trong do, canh dong Muong Thanh la canh dong Idn nhat cua tinh. Tong dien tich rimg cda tinh khoang 382.000 ha (trong dd rimg tu nhien la 374.000 ha, rimg b-dng la 7.600 ha) chiem khoang 40% tdng diSn tich tu nhidn Bo Nong nghiep va PTNT, 2019). Khoang 85% dan sd sdng a vimg ndng thdn va mien nui, nguon thu nhap chii yeu dua vao cac boat ddng ndng nghiep nhu trdng lua, ngd, va khai thac cac san pham ti: rimg (nhu mat ong, mang tre niia, duoc heu,...).
Hinh 1. Khu vvc nghita ciiu tinh Di^n Bito 2.2. Ddi tatmg nghita cihi
Trong nghita cim nay ddi tuong nghien ciiu la cac diem chay t r t a dat nong nghiep (khdng bao gdm cac dam chiy d- frong rimg va cac dita tich dat trdng c6 CO, cay gd tai sinh) tai tinh Dien Bita tii nam 2003 d& 2016 va cac nhan td anh hudng den kha nang xuat hita dam chay trta dat ndng nghiep gdm: dd cao, dieu kien vat heu chay, dita kien sinh khi hau d khu vuc nghita cuu.
2.3. Phuong phAp nghita ciiu 2.31. Thu thap so ueu
NONG NGHIEP VA PHAT TRIEN NONG THON - KS 2 - THANG 9/2020
Tat ca cac dii lita (22 biln) sir dung trong nghidn cuu nay duoc tdng bop d bang 1. Cac du lidu (gdm du lieu cac dam chay, dia bmh, thdi tidt, dieu kita vat lieu chay) duoc chuyen ddi vd do phan giai 500 m.
2.3.1.1. Da lieu chay
Cac dam chay ndng nghiep tir nam 2003 den 2016 duoc thu thap tir trang Moderate Resolution Imaging Spectroradiometer (MODIS) - Collection 6 MCD64A1 burned area product cua NASA's Earth Science program d dp phdn giai 500 m. Cac thdng tin thu thap cho mdi diem chay gom tga dd dia ly, ngay bat dau chay va ngay ket thuc chay. Nghien ciiu nay 73
KHOA HOC C 6 M G N G H E cung su dung ban do kilm ke rung, ban dd hien
trang sii dung dat d l xac dinh cae dam chay nao la chay fren dat ndng nghiep va loai bd cac diem chay trong ning, chay tren dat frdng cd ed, cay gd tai smh, cac diem chay thilu du hdu hoac bi trung Igp. Tong sd diem chay tren dat ndng nghiep la 2.860 dilm.
2.3.1.2. Duhdu cac nhin tdanh hudng den chay - Dieu kien thdi tiet 19 bien sinh khi hau (Biochmahe) duoc tai tu bo du lieu khi hau t h i gidi (Worldelime version 2.1) se duoc su dung trong nghien ciiu nay. (https://www.worldclim.org). Ben canh do chi so thoat hm nude cung duoc su dung d l phan tich. Chi so nay duoc tai tii trang https://lpdaac.usgs.gov/produets/modl6a2v006/.
- Dia hinh: Trong nghien cuu nay chi s u j l u i ^ biln dd eao d l phan tich. Lop do cao duoc hich xu^
hi ban dd dp cao toan e^u (Global Digital Elevation Map - GDEM) va dugc tai tir trang web eua Shuttle Radar Topography Mission (SRTM) (https://seareh.earthdata.nasa.gov/search?q=SRTM).
- Dieu kidn vatUdu cAaK-'Trong nghien ciiu nay, ehi sd thuc vat NDVI (The NormaUzed Difference Vegetation Index) duge su dung nhu la nhan to dai dien cho dieu kidn vat heu chay (PettorelU et al, 2005). Chi so nay duoc tai tir trang web https://lpdaae.usgs.gov/products/modl3qlv006/
cua Land Processes Distributed Active Archive Center (LPDAAC).
Bang 1. Du l i ^ dugc siJr dung d l phSn tich
Dii lidu Mdta Nguon Do phan giai
Thai tiet
Biol Nhiet do trung binh nam httpai/Zwww^.orldchnLflrg 1km
Bio2
Pham vi trung binh nhiet do ban ngay (trung binh thang (nhiet do eao nhat - nhiet do thap nhat))
hltpsL6^www3^c)ddclinLflrg
Dang nhiet ((bio2/bio7) x 100)
1km
Bio4 Sir thay ddi nhiet dd theo
mua (do lech chuIn x 100) htftisi//wvavjwQildclini.Qrg Nhidt do cao nhat eua thang
am nhat
Nhidt dp nhd nhat eiia thang
lanh nhat https'j'^/wwvL^Qrldcli: 1km
Bio7 Pham vi nhiet dd hang nam
Cbio5-bio6) https://www.worldclim.org Bio8 Nhiet dp tmng binh eua quy
am nhat ^ https: / /www, worldcl i m. org 1km
Nhiet dp trung binh cua quy
khd nhat https: / /www, wprl d iilim^ jKg 1km
BiolO Nhidt dp trung binh cua quy
am nhat https: //www, worldfli rri_nrg: 1km
Biol2
Nhiet dp trung binh ciia quy
lanh nhat https://www.worldchm.org
Luong mua hang nam Lupng mua cua thang am nhat
bttpaL//^yww,world-cLln^J^rg https:/Awww,wQrlddim,Qrg Luang mua cua thang khd
nhat
httpsL/ZwwwworldclmLarg Su thay doi lupng mua theo
miia
httESj/_/www.wQrIddun.Qrg
J , km 1 k m 1km
74 NONG NGHIEP VA PHAT TRIEN NONG THON - KY 2 - THANG . 2020
KHOA HOC CONG NGHE
Dii Hdu Biol6 Biol7 Bio 18 Biol9 Evapotranspiratio n (Evapo) Bia hinh Elevation Dieu kidn vat Ueu chay The Normalized Difference Vegetation Index (NDVI)
M d t a Luang mua cua quy am nhat Lupng mua eua quy khd nhitt
Lupng mua cua quy am nhat Lupng mua eua quy lanh nhat
Chi s6 thoat hoi nude
Do eao (m)
Chi sd thue vat
Ngudn Ixttps: / /vt'ww.worldchm.org https://www worldclim.org https: / /www. worldclim.org https://www, worldclim.org https://lpdaac.usgs.gov/produet s/modl6a2v006/
https://search.earr.hdata.nasa.0-o v/aearciilq^SKIM
https://lpdaac.usgs.gov/product s/modl3qlv006/
Dd phan giai 1km 1km 1 k m 1km 1km
30 m
250 m
2.3.2. Xulysd hdu
Si lidu thu thap se duoc phan tich su xuat hien cua chay tfieo thdi gian va khdng gian d tinh Didn Bidn. Si lieu nay duoc phan tich d l md ta cac dam chay theo thang va dd cao.
Chi so Spearman duoc su dung de loai bd nhung nhan td cd mdi quan he chat (R > 0,85) nham tranh
anh hudng cua da cdng tuyIn ciia cac nhan td trong phan tich.
Trudc khi tien hanh phan vimg nguy ca chay, da loai bd eac didn tich cd ning, mat nude, dat trdng (cd cd, cd cay bui, cay gd), mii da, khu vuc dan eu ra khdi ban do.
Xay dung ban dd phan vimg nguy ca chay: Qua trinh xay dung ban dd phan vimg nguy ca chay dupc the hien qua sa do d hinh 2.
Du B^u di^m chay tii san p h i m di^n tich c h a y c u a M O D S (MCD64A1)
Lua chon cac i£lm chay tren d^t ndng nghidp va ^ n h dang csv C*.csv)
Lap b an dd cua cac nhan tti anh hudng din chay (khi hSu, d<t cao, dilu kien vSt ^n chay)
Xii ly cac lop bandd vl dO phto giai 200 m va dinh dang ^ ^ (*.asc)
Chay p h ^ mem MaxEnt
xay dung b an dd phan c^p nguy c a chay b ang p h ^ m I m
ArcGIS m i
Xac dinh cac nhSn t6 anh hudng nhat d i n chay
Hmh 2. Quy trinh xliy dung ban d l phan vung nguy ca chay
N 6 N G NGHIEP VA PHAT TRIEN NONG THON - KY 2 - THANG 9/2020 75
KHOA HOC C6NG NGH£
Phan mem MaxEnt (Maxhnum Entropy) version 3.4.1 (duoc tai v l tir trang web lifi5si//hiQdiyersttyinfimnaticsamnh.jasZopeiL^
ceM^centZ) duge su dung ti-ong nghidn eiiu nay de xSy dung ban dd phan viing nguy ca chay ndng nghiep. Maxent la mdt thuat toan dugc sii dung pho biln trong viec du doan 6 sinh thai thich hap d l mdt loai ton tai Qane Elith etal., 2006) va da duoc nhilu tac gia diing d l du doan su xuat hien cua chay (Vermae/'^. 2018).
Dtr Hdu cac dilm chay ndng nghiep (bien phu thudc) duoc chuyin v l dang file csv (*.esv), eac biln ddc lap (gom dp cao, dieu kien vat lieu chay (ehi sd NDVI), dilu kien thai tilt) duge chuyen ve dang file acsu (*.ase). Toan bd eac biln phu thudc va biln ddc l^ip duoc dua vao phan mIm MaxEnt de xir ly va xay dung md hinh. Truoc khi chay phdn mIm nay da thilt lap mdt so thdng so trong phan mIm cu t h i nhu sau:
So dilm nIn toi da la 5000 va tiiuc hien chiic nang tiiyen tinh de tinh toan. Sd lan lap lai la 100 lan d l xay dung md hinh. Cae diem chay ndng nghidp dupc phan chia ngSu nhidn thanh hai phan gom: 75%
dupc diing d l xay dung md hinh (training) va 25%
cdn lai diing d l kilm tra k i t qua md hinh. Trung binh 100 md hinh du doan dugc sir dung d l tao ra ban d l xac xuat xay ra chay. Cac thdng so cai dat khac trong phan mIm dupc giu mac dinh.
De danh gia dd ehinh xac eiia md hinh da su dung viing bdn dudi dudng cong (area under the curve - AUC) cua vimg boat ddng dae tnmg (receiver operating characteristic - ROC) de danh gia. Gm tri AUC dao ddng til 0 den 1, neu gia tri AUC cang tidm c§n d i n 1 thi dd chinh xac cua md hinh du doan cang eao. Jakknife dupc su dung de danh gia tam quan trpng ciia eac nhan to anh hudng din su xuat hien eua dam chay.
San pham dau ra cua md hinh Maxent la mdt Idp ban do dang ASCII (*.asc) cd gia tri tii 0 (nguy ca chay thap) den 1 (nguy eo chay rat cap). Sir dung p h ^ mem ArcMap 10.1 d l chuyin lap ban do nay sang dang file raster (*.&©, sau do phan cap nguy ca chay.
Phan cap nguy ca chay dugc chia thanh bdn cap gdm: rat eao, cao, tiimg binh va tiiap. Dua tren ngudng phan loai eiia 10 phan tram bach phan vi khi xay dung md hinh, eac vimg ma mdi pixel cd gia tri
nhd ban 0,4 dupc coi la vimg cd nguy co chay tiiap, tir 0,4 d i n 0,5 dugc coi la vimg ed nguy ea chay tnmg binh, tir 0,5 din 0,6 la nguy ea chay cao va Idn hon 0,6 duoc coi la viing cd nguy ea chay rat cao.
3 . KFT QUA niCHBU CUU VA THAO LUAN
3.1. Phan bd c ^ dim chay theo thdi gian v4 khong gian
Cae dam chay ndng nghiep phan bd theo thang, dp cao va don vi hanh chinh ed su khac nhau rd ret (Hinh 3). Cac dam chay chti yeu xu^t hien vao miia khd, tap trung nhilu nhat d thang 2 va thang 3 (trdn 1.000 dam chay). Chay ndng nghiep gan nhu khdng xuat hien d cac thang trong miia mua (dac bidt thang tir thang 6 din thang 9 khdng xuat hien dam chay ndng nghidp nao). Hau h i t cac dam chay trdn dat ndng nghiep tap trung a cae huyen Didn Bidn Ddng (722 dam), Mudng Nhe (450 dam), Tuan Giao (417 dam), Dien Bien (378 dam) va Nam P i (368 dam).
Dieu nay ed the giai thich rang, cac thang miia khd vdi lugng mua va dd am khdng khi thap se giup cae vat hdu chay nhanh khd, tao dilu kien thuan Igi cho cac dam chay xuat hidn. Ben canh dd, day la thdi diem ngudi dan dia phuong tiln hanh dgn thue bi dl chuan bi cho miia trong cay ndng nghiep khi miia mua din. Trong khi dd, cac thang trong miia mua cd lugng mua va dp am khdng khi cao nen chay khd xuat hidn.
II
76 NONG NGHIEP VA PHAT TRIEN N 6 N G THON - KS 2 - THANG 9/2020
KHOA HOC CdNG NGHE
237
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Hinh 3. Sd lugng dam chay theo t h ^ (a), dO cao (b), don vi hanh chinh (c)
3.2. Vai trd ciia c ^ nhan t6 anh hudng din chiy trta dit ndng nghidp
il A
li l i i !•*0,10.1 W i i m o i B»l} Bnil5 B10I7 Ba2 B»} Bmi ElciiQw h ^ NDM
Hinh 4. P h ^ trSm ddng gdp vk tiim quan trpng ciia cac biln trong md hinh dv dodn su xu^t hi|n cua
dam chay
Phan mem MaxEnt diing thuat toan Maximum Entropy cho kit qua kiem tra su tuang quan eiia cae bien tham gia trong md hinh da xac dinh duoc cd 11 biln gom: biol, bio4, bio5, bio6, bio7, bio9, biolO, biol4, biol6, biol8 va bipl9 tdn tai su tuong quan Idn (R > 0,85) nen se khdng tham gia vap md hinh. 11 biln cdn lai khdng ton tai mdi tuong quan nao dang kl se tham gia vao md hinh. Kit qua kiem tra Jackknife da chi ra rang cac nhan t l nhiet dp (bio3) va lugng mua (biol3) cd ddng gdp Idn nhat vao su xuat hidn eua ch^y ndng nghidp dua trdn ty le phan tram ddng gdp ctia cae biln vao md hinh. Cac bien nhiet dp (gdm bio3 va bioll) la quan trpng nhat dua h-dn thii tu quan trpng (Hmh 4). Trong khi dd, eac
nhan to v l ehi so thuc vat (NDVI) va dp cao (Elevation) khdng cd anh huong nhilu din su suat hien cua eac dam chay ndng nghiep. Kit qua nghien ciiu nay cung phu hpp vdi cae nghien ciiu trudc day (Chen, 2015; Verma etal, 2018). Cae nghien ciiu nay da chi ra rSng, nhiet dp va lugng mua la nhiing nhan to quan trong anh hudng din su xuat hien eua chay.
3.3. Ban d6 phSn bd ng^y co chay trfin d^t ndng nghilp
Kit qua phan tich md hinh MaxEnt ve cac nhan td anh hudng den su xuat hien ciia dam chay tren dat ndng nghiep eho k i t qua dien tich dudi dudng cong AUC la 0,895. Dilu nay eho thay dir lieu dao tao (training data) tir md hinh cd kha nang du doan tir trung binh din tdt. Do do, k i t qua nghien ciiu nay cd the ling dung vao thuc tl, giup ngudi dan va cac nha quan ly cd nhiing k l hoach chii ddng ddi vdi chay trong khu vuc dat ndng nghiep.
Ban do phan cap nguy ca chay ndng nghidp da phan loai cac cap nguy ea chay bao gdm nguy co rat cao, nguy ca eao, nguy co trung bmh va it nguy ca.
Kit qua nay ciing cho thay ting didn tieh cua timg bac phan loai la: didn tich vimg kha nang xay ra chay rat cao la 25.000 ha, kha nang xay ra chay eao la 144.000 ha, kha nang xay ra chay trung binh la 73.000 ha va kha nang xay ra chay thap la 33.000 ha (Hinh 5 va bang 2).
Tir k i t qua nghien ciiu cho thay: Cac vimg trgng diem chay tren dat ndng nghiep cua tinh Dien Bien tap chung chu ylu d cac huyen Dien Bien Ddng (65.600 ha). Nam Po va Dien Bidn Qthoang 40.000 ha), Mudng Nhe (30.400 ha). Trong khi dd thanh phd Dien Bien Phu va thi xa Mudng Lay it nguy ca xay ra chay hon (vdi dien tich nhd hon 3.000 ha). Ket qua nay cOng cho thay ban do phan vimg nguy ca chay phan anh phii hgp vdi so luong dam chay theo don vi hanh chinh tir nam 2003 den 2016 nhu da neu d muc 3.1. Chay Idn vao miia khd cd t h i gay anh hudng nghiem ti-png din eay trdng, pha buy miia mang, gay thiet hai vl gia siie cho ngudi dan miln mii tai khu vuc nghien cim. Vdi dien tich viing nguy ea chay cao va rat cao chiem ty le Idn, Dien Bien can chii ti-png din cac giai phap phdng va kilm soat su xuat hien cua cac dam chay ti-png khu vuc canh tac ndng nghiep. Cac giai phap thich hop thich ling cho timg viing tuang img vdi timg miic dp va kha nang xay chay.
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 2 - THANG 9/2020 77
KHOA HOC C 6 N G NGHt
Bang 2. Dita tich c i c v i n g nguy CO chSy & c4c huy«n ciia tinh Dita Bito
{)on vi tinh: ha
Khu vuc Dien Bita Dien Bien Dong Difin Bita Phu Mudng Ang MuOTig Cha Muong Nhe NamPo Tua Chiia Muong Lay Tudn Giao Tong
Vimg nguy c a chay thap
750 4.900
0 250 5.300 2.200 2.100 8.500 1.500 7.500 33.000
Viing nguy co chay trung
binh 16.400 13.200 5 1.850 6.810 16.300
8.150 2.560 75 7.650 73.000
Vimg nguy co chay cao
14.820 40.000 2.650 15.300 11.750 11.900 26.500 6.680 0 14.400 144000
Vimg nguy co chay rat cao
6.950 7.500 20 2.960
80 0 3.990 1.500 0 2.000 25.000
Tong 38.920 65.600 2.675 20.360 23.940 30.400 40.740 19.240 1.575 31.550 275.000
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H i n h 5. B a n A6 p h a n b l n g u y c a c h a y t r d n d i t n d n g nghifip ciia t i n h D i d n Bidn A-KETLUANVAKHUYBUNGM 4.1. Kit luan
Kit qua nghien eiiu ve nguy ca chay tren dat ndng nghiep tai tinh Dien Bien eho titiay chay ndng nghiep tap trung vao cae thang miia khd (cao nhat vao thang 2 va 3). Bdn canh dd, chay ndng nghiep thudng xuat hien d dd cao tir 500 din 1.500 m. Cae nhan to anh hudng nhieu nhat din chay ndng nghiep
gdm cae chi tieu khi hau bio3 va bioll va tilp theo dd la cae yeu td dia hinh va d^c dilm vat lidu chay.
Nhdm nghien ciiu da phan viing nguy eo chay ndng nghiep d tinh Dien Bien theo 4 cap gom: Rat cao, cao, trung binh va thap. Trong do, vimg nguy co chay rat eao ed didn tich la 25.000 ha, viing nguy cof chay eao la 144.000 ha, viing nguy eo chay trung binh la 73.000 ha, viing nguy ca chay thap la 33.000 ha.
Kit qua nay cho thay ty le dien tich khu vuc d^t san xuat ndng nghiep tren dia ban tinh Di§n Bidn c(i nguy eo chay rat eao. Dua vao ban d l nguy co chay, cac nha quan ly cd t h i dua ra nhung giai phap thich hpp thich ling cho timg vimg tuong img vdi timg miic dd va kha nang xay chay trong khu vuc san xuat ndng nghiep.
4.2. Khuyin nghi
Kit qua nghien ciiu cung cap e a sd khoa hpc va thuc tiln eho ngudi dan va cac nha quan ly v l p h ^ cap nguy ea chay, tang cudng kha nang truy van vl thdng tin chay din cac chu hd gia dinh vdi dp chinh xac eao, dong dIu tren toan khu vue, lam eo sd cho cdng tac lap ke hoach phdng ngira va quan ly chiy, giam thilu nhirng tac ddng tieu cue do chay gay ra tren dat canh tae ndng nghiep. Tuy nhien nghidn cuu cung cdn mdt sd tdn tai, cu the chua bao gom cac nhan td anh hudng khac din chay nhu: dp doc, hudng phoi va ylu td con ngudi (nhu khoang each to eac diem chay din dudng giao thdng, mat dd dan cu) trong dir heu dau vao cua md hinh M;L\i:nt. Do vay, dua h-dn nhiing phat bien tir nghidn ciiu nay can c6 cac nghidn ciiu tilp theo nham danh gia va so sanh
78 NONG NGHIEP VA PHAT TRIEN NONG THON - KS 2 - THANG 9/2020
KHOA HOC CONG NGHE
ban d l phan viing trpng dilm chay dua trdn cac nhdm ylu td dau vao khac nhau d l dua ra kit luan ting quat hon v l viec phan cap nguy ca chay tren dien tich dat ndng nghiep tai tinh Didn Bien va mdt so dia phuong khac.
TAI UEU THAM KHAO
1. Bao, T. Q., Hoan, V. M., Hoa, N. T., Khdi, D.
H. (2019). Nghidn ciiu dae dilm vat lieu chay va phan viing nguy ca chay rimg tai Khu Bao ton Thien nhien Van hda Ddng Nai. Tap ehi Khoa hpc va Cdng nghe Lam nghiep, 5,38 - 48.
2. Bd Ndng nghiep va PTNT (2019). Quylt dinh so 911/QD - BNN - TCLN ngay 19 tiiang 3 nam 2019 vl vide cdng bd hien trang rimg toan qudc nam 2018. Ha Ndi, Viet Nam Reti-ieved from https;//luatvietiiam.vn/nong-nghiep/quyet-dinh-911- qd-bnn-tcln-2019-eong-bo-hien-trang-rung-toan-quoc- 171445-dl.htinl.
3. Chau, B. M. (2012). Nghien cim phuong phap ndi suy dieu kidn khi tugng phuc vu cdng tac dir bao nguy ca chay rimg. Tap chi Khoa hoc Ldm nghiep, 1,1-8.
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Modeling Forest Lightning Fire Occurrence m the Daxinganling Mountains of Northeastern China with MAXENT. Fprests, 6 (5), 422 -1438.
doi:https://doi.org/10.3390/f6051422.
5. Hefeng Zhang, J. H., Yixuan Qi, ChunUn Li, Jianmin Chen, Xinming Wang, Jingwei He, Shuxiao Wang, Jiming Hao, Linlin Zhang, Lijia Zhang, Yuanxun Zhang, Runkui Li, Shulan Wang, Fahe Chai (2017). Emission characterization, environmental impact, and control measure of PM2.5 emitted from agricultural crop residue burning in Chma. Journal of Cleaner Production, 149, 629-635.
doi:https://doi.org/10.1016/j.jelepro.2017.02.092.
6. Hoang, M (2007). Statiis of Forest Fire Management and Conti-ol in Vietnam. Paper presented at the GEOSS AP Symposium Integrated Observation for Sustainable Development in the Asia-Paeifie Region, Tokyo, Japan.
7. Jane Ehth, C. H. G., Robert P. Anderson, Miroslav Dudik, Simon Ferrier, Antoine Guisan, Robert J. Hijmans, Falk Huettmann, John R.
Leathwiek, Antiiony Lehmaim, Jin Li, Lucia G.
Lohmann, Bette A I/nselle, Glenn Manion, Craig Moritz, Miguel Nakamura, Yoshmon Nakazawa, Jacob McC. M. Overton, A. Townsend Peterson, Steven J. Phillips, Karen Richardson, Ricardo Scachetti Pereira, Robert E. Schapire, Jorge Soberdn, Stephen Wilhams, Mary S. Wisz, Niklaus E.
Zimmermann (2006). Novel methods improve prediction of species' distributions from occurrence data. Ecography, 29 (2), 129 151.
doi:https://doi.org/10.1111/j.2006.0906- 7590.04596.x
8. Lasko, K., Vadrevu, K (2018). Improved rice residue burning emissions estimates: Accounting for practice-specific emission factors in afr pollution assessments of Vietnam. Environmental pollution,
236, 795 806.
doi:h0;ps://doi.org/10.1016/j.envpol.2018.01.098.
9. Marco, T. G., Aidenvfronment, G. R, Profundo, M. P., CHmate, A (2020). Deforestation for Agricultural Commodities a Driver of Fires in Brazil, Indonesia in 2019. Retrieved from https://ehainreaetionreseareh.com/report/deforesta tion-for-agrieultural-commodities-a-driver-of-fires-in- brazii-indonesia-in-
2019/#:~:text=Agricultijral%20interests%20fueled%20f ires%20m%202019&text=Every%20year%2C%20Brazil%
20and%20hidonesia,more%20frequen«620and%20mor e%20intense.
10. PettorelU, N., J. O. Vik, A Mysterud, J. M.
Gaillard, C. J. Tucker and N. C. Stenseth (2005).
Using the satellite-derived NDVI to assess ecological responses to environmental change. Trends Ecol.
Evol., 20(9), 503- 510. doi:10.1016/j.tree.2005.05.011 11. Social forestry support programme (SFSP) (2019). Ddt rimg Mm nuong rSy thuc trang va bien phap khac phuc. Retrieved from https://soeialforestry.org.vn/dot-rung-lam-nuong- ray/
12. Van, T. K (2015). Phan viing khi hau cae tinh mien mii Bac bd va Tay Thanh Nghe. Tap chi cac Khoa hoe vl Trai Dat, 37 (3), 204 - 212.
13. Verma, A K, Kaliyatiian, N. N., Bisht, N. S., Nautiyal, R., & Sharma, S. D. (2018). Predictive distribution modeling of forest fire in pine zone of Uttarakhand Hunalayas of India. In D. X. Viegas (Ed.), Advances in forest fire research 2018:
Imprensa da Universidade de Cpimbra, Portugal.
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 2 - THANG 9/2020 79
KHOA HOC C 6 N G NGHE
SPATIAL PREDICTION OF AGRICULTURAL FIRE RISK AREAS USING GIS AND REMOTE SENSING TECHNOLOGY IN DIEN BIEN PROVINCE, VXETNAM
Nguyen Thi Thu, Tran Tlii Dieu, Le Thai Son, Pham Thanh Trang Summary
Fires in agricultural land can be a real ecological disaster, which threatens crops, causes economic loss, and makes distinctive impacts on the agriculture sector. Timely and accurate spatial explicit agricultural fire risk mapping is essential for prevention and suppression preparedness, resources allocaUon and better management of fires to reduce risks in agricultural industry. This study applied the Maximum Entropy algontbm (MaxEnO. using (MODIS) - Collection 6 MCD64A1 burned area product of N^^A's Earth Science program (2003 - 2016), as well as GIS and remote sensed datasets of environmental condition to identify key variables associated with fire occurrence and construct the analysis of fire risk zoning over agncultural land of Dien Bien province where fires are most likely to occur and threat existing assets of local farmers. The results showed that most agricultural fires occurred in dry season (peaked in febmary and march), at elevation class of 500 m to 1,500 m. Our results showed that Isothrmality, preapitation of Wettest month and Mean temperature of coldest quarter factors are the most important vanables in explaining the occurrence of agncultural fires. The map of potential fire occurrence indicated good discrimination between very highly susceptible, highly susceptible, moderately susceptible and lowly susceptible categones. The area of highly susceptible to fire was largest (approximately 144,000 ha), followed by the moderately susceptible category (73,000 ha), lowly susceptible category (33,000 ha) and very highly susceptible category (25,000 ha). The results indicated that the high proportion of agricultural land that is highly susceptible to fire in Dien Bien province and thus appropriate measures should be taken for each zone of different levels of fire susceptibility. This study contributed to enhance the understanding of agncultural fires and support farmers and mangers for better management of agricultural land in Dien Bien province.
Keywords: Agncultural hre, climate, remote sensing, MaxEnt, Dien Bien, Viebiam.
Ngudi phan bi$n: TS. L6 Anh Hung Ngay nhan bM: 3/4/2020 Ngay thong qua phan bien: 5/5/2020 Ngay duyet dang: 12/5/2020
80 NONG NGHIEP VA PHAT TRIEN NONG T H 6 N - KY 2 - THANG ^ /2020
