KHOA HOC CONG NGHE
[VGHIEM C I A J T D I X I G Q U A I M V E T H A I \ I S I M H HOC V A
THAIXI SIIXIH H O C BIEIV Ttl\)H
N g u y i n T h i TTiu Nh$n', N g u y e n Khac I i n h ' T6MTAT
Than sinh hpc la mot san pham cua qua trinh nhiet phan sinh khdi trong di^u kien yem klii. Trong linh virc moi truong va nong nghiep, than sinh hpc da ducrc ung dung va nghien cuu rong i ^ : trong do nhieu tac gia da ghi nhan nhung loi ich ma vat lieu nay mang lai cho moi tnrcmg, tinh chat djil va nang suat cay Cr6ng.
Tuy nhien trong mot sd trudng hpp, than sinh hpc truyen thdng cd nhieu han chel trong cai thien nang suat cua cay trong. Bai bao tdng quan nay gidi thieu tdm tat ve qua trinh san xuat, nhimg lpi ich ndng hoc cua than sinh hpc va nhung han ch^ cua vat lieu khi duoc sir dung trong ndng nghidp. Tir dd, phan tich va d$t ra nhu cau phdt tri^n mpt loai phuc hpp than smh hpc dupe bif-n tinh, lam giau dinh duong va dfe xuat cac phucmg phap ch^ tao san pham nay. Mdt sd phuong phap cd th& duoc sir dung d^ che lao san pham nay \k (i) nung hdn hpp than sinh hpc va cac vat lieu khac (vi du: dat set, da khoang, khoang chat), (ii) cac phucmg phap ti^n nhi^t phan (nhiet phan cham sinh khdi vdi hPn hpp khoang chat va cac chat dinh duong a nhi^t dp th^p 350 - 450°C), (in) phuong phap hau nhiet phan (hdn hop than sinh hpc va khoang chat/chat dinh duong/dupc ho&t hda bang nhi^t hoac hda chat n h u cac loai axit, bazo), (iv) u than sinh hpc vdi cac vat li?u hiju CO nhu phan chudng, phan xanh... Vdi ngudn sinh khdi doi dao, Viet Nam cd ti^m nang to ldn ph^t tn^n san pham nay ap dung Irong san xuat ndng nghiep.
Ti> khda: Enriched biochar, than sinh bQc, cac bon. nliietphan.
I.DATVAND^
Than sinh hpc la vat Ueu giau cac bon (C), san pham tir qua ti'inh nhiet phan sinh khoi a nhiet do tuong doi thap (< TOCC) trong di^u kien yem khi (Lehmann & Joseph, 2009). Thanh phdn ciia than sinh hgc chti yeu la C; do do khi duoc dua vao trong dat, vat heu nay se luu giir C trong dat, giam CO, khi quyen va cac anh huong cua bien ddi khi hau (Lehmann & Joseph. 2009). Than sinh hoc da duoc nghifin ciiu rat rong rai tren the gioi va tai Viet Nam, trong do cac tac gia da cong bo nhijmg dac tinh ly, hoa, sinh va cac ung dung ciia than sinh hpc trong nhieu llnh virc lien quan den moi tnrong, nong nghiep (Lehmann el al, 2006; Atkinson et al, 2010;
Sohi etal., 2010; Clough etal., 2013).
Trong thap ky qua, viec bo sung than sinh hpc vao dat nong nghiep da mang lai nhieu lpi ich ndng hoc (Chan etal., 2007). Tuy nhien, nhifeu tac gia da ghi nhan Irong nhi^u truong hpp, than sinh hoc khong thay ddi nang suat cay trdng, tham chi con lam giam nang suat. Ben canh dd, su dung than sinh hgc ket hop vol phan bon heu lupng cao lam gia tang chi phi dau vao cho san xuat nong nghiep. Tir dd dat ra nhu cau phat trien mot loai than sinh hpc dup-c
' Trudng Dai hpc Tai nguyen vii Moi tmdng Ha Ndi
lam giau chat dinh duong, k^t hgp duoc nhung dac tinh tdt ciia than sinh hoc, ddng thdi cd ham lupng dinh duong cao dap ung dupe nhu c&u cua cay trdng.
Z. TONG QUAN TAI lEU VA THAO LUAN 2.1. Than sinh h p c truydn thdng 2.1.1. Nguyen lieu va phuong phap san xuat Cac nguyen lieu va dieu kien san xuat khac nhau se tao ra nhung loai than sinh hpc khac nhau (Lehmann & Joseph, 2009). Qua trinh nhi^t phan than sinh hpc duoc chia lam hai loai la nhiet phan nhanh va nhiet phan cham. Nhiet phan nhanh dupe thuc hien d 450''C den 600"C trong mot vai mili giay dgn vai giay (Laird etal, 2010; Cayuela etal., 2013), trong khi do nhiet phan cham duoc thuc hien d- nhiet dp thap dudi 400"C trong mot vai phut den vai gid (Cayuela etal., 2013). Cac nguyen heu san xulit than smh hpc bao gdm cac phe pham lam nghiep (vi du:
chat thai gd), chat thai cong nghiep (vi du: chat thai tir nha may san xuSt giay), biin thai, phan chudng, chat thai nong nghiep (vi du: rom ra, vd trau),...
(Chan et al., 2007; van Zwieten et al, 2010). Ti6m nang phe phu pham ndng nghiep tai Viet Nam co th^
su dung de san xuat than sinh hoc da duoc thdng ke rat chi ti^t trong cac tai lieu da cong bd (Bp Tai nguyen va Mdi tnrdng, 2010; Tdng cue Thdng ke, 2013; Du an hd trg nong nghiep cac bon thap, 2015).
So lieu thong k i nam 2015 cho thay nguon phe phu pham lai \'iet Nam tu cac cay trong chinh Oiia, ngo, mia, lgc. dau ttiong) la 76,76 trieu tan, trong do co 53,77 trieu tan ph^ phu pham tir cay liia, 12 trieu tan tir cay mia va gan 10 trieu tan phe phu phara tu cay
Bang 1. Ngu6n ph^ phy p h ^ ndng nghidp nam 2015
ngo (Du an h6 trg nong nghiep cac bon thap. L'Ol.'il Do do, nguon sinh khoi diing cho san xuat than sinh hoc la rat ldn do nguyen li«u phong phu va gia thanh
Don vi tinh: tdn
Tmh Son La Lao Cai Phii ITio Bac Giang N a m Dinh Ha T m h Binh Dinh Ti^n Giang BSn Tre S6c Trang Tdng lupng
Phe thai trong trot
1435601 492456
Phe thai \ Phe thai chan nuoi ! thiiy san
4864765 i 2284281 ' 541064 2962885 1775206 ' !l7992,'i:i 1689451
769035 2294110 2072603 812176 227514S 14156850
2009822 3304000 3729655 2138667 2422995 976498 34492851
3700 2500 14485 27000 12822 60507
Tong luong 6300366 2776737 3503949 11574489 3699273 4076735 6026265 4225755 3262171 3264468 48710208 Ngudn: Danh gia nhu cau dao tao nghe su dung phe phu pham ndng nghi$p va san xuat ndng nghidp cac
\ bon thdp, Dif^i hd tr(r ndng nghidp cac bon thap (LCASP) (.Miung. 2015) Cf nude ta da co rat nhi^u nghien cuu ve cong
I ngh^ san xuat than sinh hpc. Vi^n Moi truong Nong . nghiep (Vi^n Khoa hpc Nong nghidp Viet Nam) da ch^ tgo than sinh hpc tir trau. ba mia, ram ra, dam
\ gb, miin cua, ngo, ca ph6. Lo dot than sinh hpc cung da dupe Truong Dai hpc Nong Lam, Dai hpc Hu^
I nghit^n cuu va che- t^o thanh cong voi cong suat tir 50 d^n 300 kg trau nguyen li^u/me voi hieu suat thu hdi than cao (95-99%), it tao klioi va khi thai, giam thi^u thoi gian ddt va cong lao dpng. Mpt sd co sa tai nhieu dja phuong tren ca nude cung da san xuat va dua ra thi tnrong cac san pham than sinh hoc tir niiin cua ciia cac loai gd tgp, ngoai ra dupe trpn tliem v6 lac, vo train, than cay ng6, loi bap ngii. ba nrou va ba mia (Phii Thp, Tuy^n Quang), than sinh hoc tir cay bach dan rimg trdng (Binh Djnh) ... Hien nay, viec san xuat than smh hpc nicri chi dimg a quy mo nho le, phan bo rai rac tai cac khu virc bring du mien niii, noi CO nhi^u tiem nang phu pham nong nghiep va cung chira co thdng ke chinh thiic ve sd lirong duoc san xuat.
2.1.2. Vai trd ctia than sinh hpc
Da CO rat nhieu tai li?u phan tich, danh gia vai trd va ung dyng ciia than smh hpc tren the gioi va tai Vi^t N';un. Cac img dung tieu bidu cua than sinh hpc
CO the duoc k^ de'n nhu cai thien tinh chat dat, tang nang suat cay trdng, co lap C gnip giam nh? bi^n ddi khi hau, xu ly chat 6 nhilm, cai tao moi trtraig (Blackwell etal, 2009; Mai Thi Lan Anh va cs, 2012;
Nguyen Dang Nghia, 2014; Nguyin Dang Nghia va Luong Hdng Son, 2017). Cac nghien cthi trSn th^ gioi va d \'iet Nam da cho Ih^y than sinh hpc tir cac loai phu pham nong nghiep cd th^ duoc su dung nhu la chat hap phu, chat dinh duong v.v. gidng nhu cac loai than bun va than hoat tinh. Ben canh do, than sinh hpc con CO hieu qua trong viec su dung tai nguyen;
gop phan cai thien, khdc phuc va/hoac bao ve, han che 6 nhiem moi hirong, giiip giam thieu phal thai khi nha kinh (Lehmann & Joseph, 2009; Tran Thi Tu va cs. 2013), Than sinh hgc rat giau C, do do nd can trd hoac ngan chan hoan toan su phat tan cua C trd lai bau khi quyen duoi dang khi CO;,. Trong khuon khd bai viet nay chi tap hung de cap den cac img dung cua than sinh hoc ddi voi nong nghiep.
Trong thap ky qua, viec bd sung than sinh hpc vao dat nong nghiep da mang lai nhieu loi ich nong hoc (Chan etal, 2007). Nhirng lpi ich duoc bao cao bao gdm cac tinh chat vat ly va hda hoc ciia dat duac cai thien nhu tao do loi xdp, tang chat hiru ca, pH, kha nang trao ddi cation (CEC). kha nang giir nu6c
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 9/2019
KHOA HOC CONG NGHE va dinh dirOng cung nhu thiic day luu trii C lau dai
trong dat (Lehmann etal.. 2011; Xu etal., 2015). Cu the:
Viec dua than smh hpc v4o dat cd the thay ddi thuOc tinh vat ly d^t nhu k^t can, cau tnic, phan bd, dung trpng va kich thuoc mao quan. Dieu nay cd y nghia ddi voi che dp khong khi dat, kha nang giu nude, tang trudng thuc vat va kha nang cay xdi dat.
- Than sinh hpc cd the lam tang tdng dien tich b^ mat ciia mang ludi mao quan va dien tich khoang hdng trong dat nho cd sd lupng Ion cac Id hdng tren be mat va do dd cd the cai thien kha nang giii nuoc cua dat va tang cudng su luu thong giiia khong khi dat vdi moi tnrdng ngoai (Downie et al, 2009). He sinh vat d^t do do cung phat tri^n.
- Gia tri pH ciia than sinh hoc thudng trung tinh va kidm nen cd the dupe sit dung de cai tao do chua cua dat.
- Su tich luy cac hgp chat hiiu ca ki nuoc (vi du nhu PAHs, polychlorinated biphenyl- PCBs, thudc trir sau, thudc diet cd) trong dat va tram tich nho dong thdi 2 qua trinh: su hap thu (absorption) va hap phu (adsorption) tren vat lieu than (Comelissen el al, 2005).
- Giam rira ti-6i chat dinh duong, tang thdi gian chat dinh duong cu tni trong viing rl; didu nay cd Hen quan den tang cudng hieu qua su dung chat dmh dirong ciia cay.
Tai Viet Nam mot sd tac gia da nghien cuu che tao than sinh hoc de lam phan bdn (Mai Thi Lan Anh, Dai hpc Khoa hpc Dai hoc Thai Nguyen), lam gia the, dat nhan tao va phan bdn hiru covi sinh de san xuat hoa cay canh va cac loai rau dac san (Vien Thd nhuong Nong hda), san xuat than sinh hoc tir luc binh phuc vu cho san xuat nong nghiep (Trung tam Nghien cuu Bit va Moi tnrdng phia Nam).
Tuy nhien, than sinh hpc nguyen chat bdn vao dat da cho thay cac ket qua khac nhau ve nang suat cay trdng, bao gom mpt sd tac dong lieu cue do than sinh hpc cd kha nang hap phu rM ton, vi vay lam giam ham lupng dinh duoug de tieu trong mpt khoang thdi gian sau khi bdn. Ngoai ra, ham luong dinh duong ti'ong ban than nhieu loai tlian sinh hpc nguyen chat khong du dap ung dupe nhu cau cay trdng. De giai quyet sir suy giam ve nang suat cay trdng, than sinh hpc da duac ket hop voi phan bdn tdng hpp, duoc su dung nhir mot tac nhan de cai thien hieu qua ciia phan bon va gan day nhat duac
tang cudng bang each ket hop vai dat set va khoang chat de tao ra cac phuc hpp de bdn vao dat (lin etal., 2013; Farrar etal., 2019). Tuong tu tai Viet Nam, cac tac gia cung nhan thay nhiing lac dpng cua than sinh hpc den giam nang suat cay trdng. Vi du, thii nghiem O' Thai Nguyen va Thanh Hoa, than sinh hpc tii rom, trau, tre va cay gd duoc bdn vao dat da giam 32%
nang suat lua so vai khi bon phan NPK (Nguyen Cong Vinh va cs., 2014). De cai thien nang suat cay trdng, cac tac gia ciing da thu nghiem bdn ket hap than sinh hpc voi cac san pham phan bdn vo ca va hiiu ca. Thu nghiem tai Ninh Thuan nam 2014 cho thay than sinh hpc tir trau ket hop vai phan xanh va NPK da tang nang suat dau phong d mirc cao nhat so voi chi bdn duy nhat than sinh hoc, phan xanh, NPK hay bdn ket hop than sinh hpc voi mot trong hai loai tren (Scholze/'a/.,2014).
Quan niem hien tai ve su dung than sinh hpc thuong lien quan ddn viec bdn vol lieu lupng cao vao dat mpt lan duy nhat de cai thi^n dp phi va co lap C khong cdn phii hpp d' nhieu noi tai cac nude phat trien hoac dang phat trien (Woolf etal., 2010). Do do, thi trudng than sinh hoc nhd be hidn nay dupe su doan se liep luc phat Iriln trong tuong lai, trir khi nhirng tieln bp dang ke dupe thuc hi^n trong vi^c phat trien cac loai than sinh hpc cd hieu lire cao, bdn vcri lieu lupng thap, cd the cho nang suat cao han phan NPK voi chi phi thap hon, ngoai ra co gia In gia tang duoi dang tin dung C. Hipn tai, Trung Qudc la qudc gia duy nhat san xuat thuong mai cac loai phiic hpp than sinh hpc nay, vdi quy mo hien nay hon 40.000 tan moi nam. Sir dung nhiing lien bo trong linh vuc phat trien than hoat linh, vat lieu composite dua tren C kich thuoe nano va ky thuat sinh hpc phan tu cd the bien than sinh hpc tir mpt san pham dupe san xuSt bdi mpt sd it doanh nghiep voi chi phi dau vao cao sang mpt san pham nong nghiep co the dupe kinh doanh voi chi phi phii hop. Cac san pham than sinh hoc van chua dupe ap dung trong nong nghiep tren quy mo rpng do chi phi img dung va loi tiic dau tu kinh te tuong ddi dai han Uoseph et al, 2013). Do do, nhu ciu phat trien mpt loai than sinh hpc hieu qua cao voi chi phi thap la rat can thiet.
Ddng thdi, de than sinh hpc cd dong gop hieu qua trong viec ddi moi san xuat d nong thon va cai thien ddi song nguoi nong dan, van de dat ra la lam sao dua cac cong nghe va thiet bi san xuat than sinh hpc img dung vao thuc tidn hieu qua va phii hpp voi dieu
\
kien cua nong thdn Viet N.im. Tu do. da dd xuat thay the tlian sinh hpc tmyen thdng bang than sinh hoc dupe bien tinh nham giam chi phi dau vao. giam lupng than bon vao dat. dong thoi tang hieu sual sir dung dinh dufimg va cai thien nang suat cay trdng.
2.2. Xu hudng nghifin oiu: San xuat than sinh hpc bi^n tinh trong cai tao dit va dinh duong cay trdng
2.2.1. Ly do bien tinh than sinh hoc
Than sinh hpc dupe bien tinh (Enhanced biochar - EB) dupe dmh nghia la san pham than sinh hpc dirpc sir dung a lieu lupng thap nhung dat hieu qua cao hon so vai than sinh hpc truyen thdng Ooseph etal.. 2013). Enhanced biochar bao gdm ca than sinh hpc dupe lam giau dinh duong (Ennched biochar) va than sinh hpc dupe bien ddi tinh chat, tang kha nang hap phu... Co nhieu phuong phap tiep c^n khac nhau d^ tao ra san pham EB va phan ldn trong sd dd lien quan den viec xu ly than sinh hoc voi Ctic vat li^u giau dinh duftng va re ti^n (vi du. chat hitu CO, bim, phan bon hda hpc, khoang dial) .|CJosephef.7/.2017).
Ung dung EB trong dat co rat nhieu uu diem so vol su dung than sinh hpc truyen thdng. Cu the, ddi vdi lliirc v^t, EB rat giau chat dinh duong da lupng va vi lupng, do dd dupe bon vai lidu lupng thap nhung van dap ling dupe nhu cau ciia cay trdng, ddng thoi giam chi phi dau vao so vai than sinh hpc truyen thdng Ooseph el al., 2013). Them vao do. EB co tdc do khoang hoa chgni hon nhieu loai than sinh hpc, va do do ddng vai trd nhu mpl loai phan bdn giai phdng ch^m chat dinh duung (Chia etal, 2014). Ddi voi dat, EB giam mat nita (N) nhd kha nang trao ddi cation (CEC) Idn hon nhieu logi than sinh hpc khac Ooseph era/. 2013).
2.2.2. Gidi ihi^u cac phuong phap che tao than smh hoc bidn tinh
EB CO the dirpe san xuat bang nhidu phuong phap khac nhau nhu (i) nung hdn hop than sinh hpc va cac vgt li^u khac (vi du: dat set. da. khoang chat) (Un et al., 2013). (ii) cac phucmg phap lien nhiet phan (nhiet phan cham sinh khoi vd\ hdn hpp khoang chat va cac chat dinh duong d nhiet do thap 350 - 450 C). (iii) phuong phap hau nhiet phan (hdn hop than sinh hpc va khoang chat/chat dinh duOng/duin.- hoat hda bang nhiet hoac hoa chat), (iv) li than sinli hoc vai cac vat lieu hiiu ca Ooseph etal..
2013). Cu the, da dira ra nhiing quan didm s;ui de phat tnen cac san pham EB bbn heu thap. hieu qua cao. San pham EB idi uu co loi than sinh hpc xdp d ben trong, kho hi khoang hda. chiia nhieu chat dinh duong da lupng, vi lupng bao phu ben trong cac Id hdng va tren be mat ben ngoai cua v^t lieu. Cac phiie hop EB nhu vay co the dugc phat trien theo mpt sd phuong phap nhir
Hdn hop dat set, khoang chat va/hoac cac hpp chat hoa hpc dupe bd sung vao than sinh hpc sau qua trinh nhiet phan. Mpt sd nghien ciiu da chimg minh rang than sinh hpc dupe xir ly voi tro sau khi ddt ciii gd, kali hydroxil (Lin etal., 2012; Lin et al, 2013) hoac cac chat khac (vi du, cac chat humic tir than nau hoaclhan biin (Wu etal,2011) da lam tang ty le nay mam, siic de khang sau benh va kha nang hap thu dmh duong ciia cay. Hdn hgp EB nay duoc tao thanh b^ng each su dung mot chat k^l dinh de tao ra mpt sail pham ddng nhat. Mpt sd vi du cua chat kel dinh la lignin, tinh bpt, canxi hydroxit va natn hydroxit (Hu etal, 2015).
Than sinh hpc sau khi nhiet phan se dupe kich hoat bang axit hoac bazo, sau dd trpn them voi cac hpp chat hiiu co va/hoSc khoang chat khac Oibril eM/, 2008)
Sinh khdi duoe ngam trong dung dich giau dinh duong va giau khoang set. Sau dd, sinh khdi dupe say kho va se duac nhiet phan. Nhiet do nung duoe dieu chinh d^ kidm soat tdc dp giai phdng cac khoang chat va thanh phan hiiu ca khong bdn.
Sinh khdi dupe phan ung voi axit photphoric, sau dd Iron ciing cac chat dinh duong va khoang set.
Hdn hop nay dupe nung den nhiet dp thich hpp de tdi uu hoa cac nhdm chirc va dien tich be mat cua vat lieu. San pham sau do dupe u cimg chat hiiu co va duac vien lai sau khi qua trinh u phan hoan thanh.
San pham than sinh hoc dupe hoat hoa bang phuong phap sinh hpc (u hoac len men than sinh hpc voi phan gia siic, gia cam. nuoe tidu va tro) (Fischer
& Glaser, 2012). San pham ciing co the duoc bd sung them cac vi sinh vat co loi.
Cac san pham EB se dupe san xuat tiiy theo muc dich sir dung, tinh chat dat, dac diem cay trong, khi hau, nguyen lieu sinh khdi san xuat than sinh hoc cd san... Cac san pham nay dupe sii dung voi heu luong thap do rat giau chat dinh duong. Khong co su khac biet trong lich trinh bon phan va eac phuong phap canh tac khi su dung EB so voi thong thu<nig
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 9/2019
KHOA HOC CONG NGHE
Ooseph etal, 2013). X\ le phdi trpn cac thanh phan trong EB dupe tmh toan phu thuoc vao muc dich su dyng, ddi tupng cay trong va tinh chat dat; do do kh6ng cd cong thiic cd dinh nao d^ che tao san pham nay.
2.2.3. Chi phi va hidu qua kinh tecua than sinh hoc bien tinh
Chi phi san xuat than sinh hpc phu thupc vao rat nhidu ydu id nhu thu gom va van chuyen nguyen li^u, cong nghe san xual, quy mo san xuat, phan phdi va xtr ly san pham (Kulyk, 2012). Do dd, gia thanh san xuat than sinh hpc la khac nhau d cac qudc gia.
Nhin chung. chi phi san xuat than sinh hpc d cac nude phat hien cd gia US$300 den $7000/tan Ooseph et al, 2013). Vi du d Anh, chi phi cho san xuat, phan phdi va sir dung than sinh hpc la US$222 d^n $584/tJin (Shackley etal, 2011). Tai Viet Nam, cac san pham than sinh hpc dupe rao ban thuong mai vdi gia khoang hon USS500/tan (12.000 VND/kg vd trau hun san pham ciia Cong ty VinaTap Viel Nam),
Ddi voi EB, chi phi duoe udc tinh khong qua cao so vdi chi phi san xu^t than sinh hpc. Vi du, Fairar et al (2019) da tinh loan chi phi sic dung than sinh hpc thuong mai va EB tai Uc nhu sau:
Than sinh hpc tir tre dupe san xuat thuong mai va dupe mua tir Cong ty SEEK Bio-Technology Thuong Hai. Tning Qudc voi gia US$400 den
$800/tan.
Phiic hpp than sinh hpc duoc lam giau EB (d tren da dd cap) dupe san xuat thuong mai vai gia US$425/tan.
Nhu vay, chi phi de san xuat thuong mai than sinh hpc va EB khong qua chenh lech. Didu nay c6 the giai thich do san xuat EB khong yeu cau dau tu them Ihiel bi so voi san xuat than sinh hpc truyen thdng. So VOI llian sinh hpc tniydn thdng, EB ddi hdi them chi phi danh cho cac nguyen, vat lieu vo cova hiiu CO bd sung vao than sinh hoc, de hoat hda san pham va xu ly san pham bang nhiet hoac hda/sinh hpc. Do dd, chi phi chenh lech khong cao, hiia hen EB la mpt san pham co the dua vao san xuat thu nghiem va ling dung tai Viet Nam.
2.2.4. Anh hirdng ciia than sinh hoc bien tinh trong viec cai tao dat va dinh dudng cay tiong
O day se trinh bay co chpn Ipc mot sd vi du trong tai Ueu va cac nghien ciiu dien hinh gan day
nhat de thao luan ve each thuc EB giiip dap ung cai thien tinh chat dat va nang suat cay trdng.
- Than sinh hoc hdn hop: Nguydn Cong Vinh va cs (2014) da san xuat mpt loai than sinh hpc hdn hpp tir trau, tre, rom va phan chudng trong mpt Id nhiet phan, trong dd nhiet dp thay ddi tir eOO^C d- dinh den 400°C d day cua Id. Hp da sir dung than smh hpc nay d cac ti le 0,5 va 2,5 tan / ha kdt hpp ciing NPK bdn cho cay Ilia. Kdt qua cho thay nang suat liia da tang 5,9-22,3% trong cac thi nghiem bon ket hpp NPK va than sinh hpc. Trong mpl thi nghidm khac. Nguyen Cong Vinh va cs. (2014) cung Iron phan hiiu co vai 5% than sinh hpc va bdn voi li le 10 tan/ha cho lua va 20 tan/ha cho rau; ket qua san lupng Ida tang trung binh 30% va san lupng rau tang 15% so vdi ddi chimg.
U phan than smh hpc. Khi than sinh hpc dupe them vao phan ii, tinh chat ciia chiing co the dupe cai thien. Kammann et al. (2015) da che tao EB bang each Iron sinh khdi go voi dat set (cd ham lirong Fe va Mn cao) sau dd nhiet phan d 700"C tao ra than sinh hpc; san pham sau d6 lai dupe ii ciing phan chudng trong khoang thai gian 40 ngay de lao ra EB.
Khi bdn vao dat vdi ti le 2%, cho thay nang suat smh khdi ciia cay cay Diem mach {Cbenopodium quinoa) tang len tdi 305% tren dat cat ngheo dinh duong.
Nguoc lai, bd sung 2% than sinh hoc chua dupe xu ly vol phan chudng da lam giam sinh khdi cay Diem mach xudng 60% so vdi ddi chimg. Sic dung phuong phap sieu loc (Electro-ullrafiltration) va nia hat sinh hpc tuan tu (Sequential biochar-particle washing) cho thay rang EB da dupe lam giau bang chat dinh duong, dac biet la vdi cac anion nitrat va phdt phat nhd qua trinh ii phan. Ca hai phan ling sinh hpc va phi sinh hpc tren be mat ben trong va ben ngoai cua than sinh hpc diln ra trong qua trinh u phan, trong do mpt loat cac phiic chat hiru co hinh thanh tren bd mat than sinh hoc trong qua trinh nay khien cho san pham cd ndng dp cao cua cac nhom chiic axit va bazo. Cac ldp nay cd dp xdp tdn va lien ket hydro khong theo quy ude dudng nhu chiu trach nhiem thu giir nitrat va phdt phat.
Xu ly tidn nhiet phan va hau nhiet phan than sinh hoc vdi khoang chat, set, hda chat: Bd sung khoang chat, tro, xuong dpng vat va dat vao sinh khdi trude khi nhiet phan de tang cudng tinh chat san pham da dupe ap dung tren the giai (Lehmann »&
Joseph, 2009). Li et al (2014) nhan thay rang bd sung Ca(H2PO,)2 lam tang nang suat va ham luong C
cua than sinh hpc len toi 29% so voi than sinh hpc chua dupe xir ly, trong khi set cao lanh va canxit it cd tac dyng. Hp cung phat hien ra rang canxit va Ca(H_,P04)2 da bao ve than sinh hpc chdng lai cac bien ddi hda hpc va su ket hpp cua ca ba khoang chat CO the bao v^ than smh hpc khdi sir tan cong cua vi sinh vgt khi bon vao dat. Chen et al. (2011) ddng k^t tua hoa hpc Fe /Fe^' tren bpt nghidn tir vo cam va sau dd nhiet phan hdn hpp sinh khdi va hdn hpp Fe dudi cac nhi^t dp khac nhau (25a C. 400"C va 700"C).
Phan tich cac vat li^u tdng hpp than sinh hpc va Fe cho thay su hinh thanh cac hat nano tir tinh Fe,03 tren bd mat ciia than sinh hoc. Hp phat hien ra rang a 400"C, hdn hpp hap phu nhieu phan tu hiiu co (naphthalene va p-mtrotoluene) hon so vcri vat lieu tdng hpp dupe san xual d nhiet dp khac va nhieu hon than sinh hpc don thuan. Hdn hpp dupe san xuat d 250"C ciing hap phy them phdt pho.
Mpt sd nghien ciiu ve uen xir ly be mat sinh khdi bang axit ho$c bazo da dupe thuc hien. Hina et al.
(2010) da xOr ly vd cay b^ch dan va cay thong v6i chat thai thupc da co tinh kiem dupe pha loang hoac khdng pha loang, sau do nhiet phan a 550"C. Cac tac gia nh$n thay rang dien tich be mat than sinh hpc giam nhung ham lupng cac nhdm chiic axit tang len.
Trong cac thi nghiem hap phu, than sinh hpc dupe xu ly giii 1^ ham lupng NH^* Ion hon. Su giai hap la rat th^p, dac bidt la trong than smh hpc dupe xir ly so voi than sinh hpc chua dupe xir ly (0,1-2% so vai 14- 27%).
Xii ly hgu nhiet phan than sinh hpc la phuong phap kha phd bi^n va mpt sd san pham da duoe ban ra tren thi trudng Ooseph & Taylor, 2013). Cac phtrong phap phd bien nhat dupe su dung bdi cac cong ty Ihuong mai la u phan (co hoac khong them khoang chat va vi sinh vat) va than smh hpc phan ling voi phan bon hoa hpc NPK. dat set va khoang chat. \ i du. ket qua thii nghiem tliuc dia so bp tren
_ Bang 2. Thay ddi hap thu N p re. than vajiayrmigcactinjighiem khac nhau
cay Ilia dupe thue hien bdi Dai hpc Nong nghiep Nam Kinh (Giang TP, Trung Qudc) voi phiic hpp hi than sinh hpc EB da quan sat thay nhiing cai thien trong phan img cua cay trdng so voi phan hda hpc XPK Ooseph et al., 2013). Than sinh hoc duoe san xuat tir rom Ilia mi bdi Cong ty Nang lupng moi San Li (Ha Nam. Trung Qudc) trong mot may khi hoa o nhiet dp khoang 460-500°C. Sau do. than sinh hpc nay dupe trpn voi cac thanh phan khac dieo ti le tiian sinh hpc tir rom liia mi (25%), set bentonite (5%), ure CO(XHJ.. KCl va monoammonium phosphate de t?o tiianh mpt phuc hpp bdn vao daL Cong thiic nay cho ty le khdi luong N:P.05:K.O la 18:9:10 hong 100 g san pham. Cac tiianh phan ti-en dupe trpn va cho phep phan ling voi nhau trong cac thimg kin tai didu kien moi truong binh thirdng trong khoang thdi gian 4 tuan. Phirc hpp than sinh hpc va phan NPK (ddi chiing) ddu dupe bon vao dat voi ham lirpng 450 kg/ha. Ket qua eho thay phiic hop da tang dang ke luong N hap thu d hat gao (Bang 2), tSng bdn chi sd so voi phan hoa hpc NPK; dd la chi sd thu hoach ciia hat (= nang su^l lua/san luong sinh khdi tren mat dait). hieu suat lao hpt ciia N (= nang suat lua/tdng N trong cay liia), chi sd thu hoach ciia N (= tdng N ciia bong lua/tdng N trong cay lua), nang suat N (= nang suat lua/tdng N dau vao) (Bang 3). Tinh chat ly hda cua than sinh hpc tir rom lua mi va phirc hpp than sinh hpc dupe phan lich, tir do cac nha khoa hpc da Um ra ring nhung thay ddi trong cau tiijc vi rat va nano cua phiic hpp da gop phan cai thien phan img cua cay trdng. Trong phirc hpp than sinh hpc. set bentonite va cac hda chat khac da phan ung vdi tiian sinh hpc; ddng thdi da co su di chuyen cua cac cation va anion hoa tan vao cac Id hdng ciia than sinh hpc.
Nhiing tiiay ddi nay dan den tang ham lupng dinh duong va do do, lang sy hap tiiu chat dinh duong ctia
Till TILjllH'm I'liaji Nl'K P h u c h a p Uiaii h o c
H a m l u o n g N (g/k^') R^ ' T h a n , Hat l.:').iA l0.54,L-\ , 1 . 2 V J A siiih't>-t'l ± \b.bb± 1 13.4>±
0.74bA 0.1 SbB |().:9.iA
N h a p Ihu (kR/ha) Than 5 ' S5 ± 'J.6(laA J8.5I ± 3,83aA
Hal 124,67 ± ll.43aA I.'i3.56±
15,02aA
N h a p t h u a h a t / N h a p t h u crthan 2.34 ± 0.24bB 3 . 1 7 ± 0 , 1 7 a A
^... ...^. .... .o.i tri ixfi cac chu cai vidt tiiudng cbi ra sir kbac biet v4 thdng ke (p <0.05). cac gia tri vdi cac chuin hoa chira sural khac biet ve thdng ke (p <0,01)
NONG NGHIEP VA PHATTRIEN NONG THON - KY 1 -THANG 9/2019
KHOA HOC CONG N G H l
BJnK 3. C&; chi s i hieu qua su dung N cua liia trong cac tiii n g h i ^ khic nhau Thi nghidm
Phan NPK Phiic hop than sinh hoc
Tong N da bon (Itg/ha)
210 168
Hieu suat tao hat ciia N (kgAgN) 39bB 68aA
Chi so thu hoach a i a hat
ftg/iig) 0,24bA 0,28aA
Ciii sd thu hoach cua N
(kg/kg) 0,70bA 0,76aA
Nang suat N (kg/kg)
46bB 56aA Ghi chii: Cac gia tii vdi cac chd cai viet thiing chi ra sir khac bietvS thdng ke (p <0,05), cac gia tn vdi cac chain hoa chira sir rat khac biet ve thdng kd (p <0,01)
Nghien ciiu cua Farrar et al (2019) hen dat set nau cung da cho thay phiic hpp EB cd nhiing tac dpng tich circ deh tinh chat dat va san luong cay gimg. Nhdm tac gia da so sanh hieu qua ciia phan bdn than sinh hpc Ihuong mai tir Cong ty SEEK Bio- Technology Thuong Hai, Trung Qudc (san xuat tir than tre, tro tre. gi^in Ire. bpt cam gao, can dau va nude) va phiic hpp EB tu che tao bang phuong phap hau nhiet phan hdn hop than sinh hpc tir tre, phan ga, thach cao, da phosphate, boron dang hat, kah sunfal, rom liia mach, oxit sat va dat set Phan bdn than sinh hpc thuong mai dupe bdn vao dat voi ti le 5 tan/ha, trong khi dd phuc hop EB duac bdn vao dat vdi hai U le khac nhau: ti le thap (3 tan/ha) va ti le cao (7,5 tan/ha). Kdl qua cho thay EB dupe bdn vao dat vdi ti le cao tang gia tri thuong mai cua cay gimg 36% do tang ti le cu cd kich thudc ldn. Ddng thdi, EB d ca li 1^ cao va thap deu tang tdng lupng sinh khdi kho ciia cay va san lirong cu. Ca che hoal dong cua EB trong nghifin ciru nay dupe giai thich rang EB da lam tang ham lupng cac chat dinh duong cho cay.
Viec bd sung cac chat dinh duong hiiu co, khoang chat va oxit sat ti-ong EB da tang lien ket cua P va cac chal dinh duong khac len be mat cua san pham.
Ngoai ra, qua trinh xir ly hau nhtet phan EB cd the phan hiiy C trong tiian sinh hpc va phan ga dan den tang ham lupng C hiiu co hoa tan hong dat (DOC).
DOC tang len da hd tro qua trinh hda tan khoang chat P vi DOC cd the phan ling vdi cac khoang chat va dat set, ngan chan su hap phu P vao than sinh hpc, do dd lam tang ndng dp P linh dpng trong phau dien dat.
Nhu vay, mac dii vin dang dupe nghien ciiu va thu nghiem tren the gidi, EB la mpt san pham hira hen mang nhiing uu diem cua tiian sinh hpc, nhung ddng thdi van chiia ham lupng dinh duong cao dap ung nhu cdu cua cay trdng.
Tai Viet Nam, mot sd tac gia da nghien cuu che tao va ting dung EB trong nhiing nam gdn day. Vi du.
Vu Thi Mai va Trinh Van Tuyen (2016) da che t^o than sinh hpc dupe lam giau tir loi ngo ngam vdi axit H3PO4 50% trong 24 h va nung hong 16 nung tai 400''C. San pham dupe ti^p tuc ngam vdi NaOH trong vong 24 h, sau do dupe khao sat kha nang xir ly amoni trong nuoe. Tuy nhien, cac nghien ciiu che tgo than sinh hpc dupe bidn tinh de su dung trong nong nghiep cdn rat han che. Nam 2014, tai Vien Thd nhuong Nong hda, phan hiru co khoang thd he mdi da dupe san xuat tir than sinh hpc bang phuong phap trpn sinh khdi (vd trau, mun dira, vd ca phe, vo hau) vdi phan NPK va cac vat Ueu hiru co khac giau miin vdi cac ti le phdi trpn khac nhau dd bdn cho cay lua, ngo va rau mau (Nguydn Dang Nghia, 2014). Tuy nhien ket qua so sanh hieu qua giira loai the he mdi nay va phan NPK hay than sinh hpc truydn thdng chua dupe bao cao. Do dd, than sinh hoc dupe lam giau can dupe tiep tuc nghien ciru ling dung va phat trien tai Viet Nam nham tan dung nhiing uu diem nhung han chd nhung tiiiieu sot cua than sinh hpc truydn thdng.
3.KFTLUAN,KBUNGHI
Than sinh hpc da dupe nghien cuu vi ling dung hen the gioi va Viet Nam; song nhiing anh hudng cua than sinh hpc len tinh chat dat va nang suat cay hdng cdn nhidu han che. Do dd, than sinh hpc bien tinh la mpl huong di mdi day hiia hen se mang lai nhidu loi ich va uu diem hon than sinh hpc truyen thdng. Voi ngudn phe phu pham ddi dao, Viet Nam cd liem nang lo ldn de phat trien san pham phiic hpp tir than sinh hoc nay de sii dung hong nong nghiep gnip cai tiiien tinh chat dat va tang nang sual cay trdng, ddng thdi giam chi phi ddu vao. San pham nay CO the dupe san xual bang nhidu phuong phap nhu xu ly nhiet va hda chat trudc va sau qua tiinh nhiet phan sinh khdi hoac than sinh hpc, u phan,... voi cong thlic duac tinh toan phu hpp vdi muc dich su dung.
TM UEU THAM KHAO
1. Atkinson Christopher J., jean D. Fiugerald. &
Neil A. Hipps (2010). Potential mechanisms for achieving agncultural benefits from biochar applicaUon to temperate soils: a review. Plant Soil 337,1-18.
2. Blackwell Paul, Glen Rietiimuller. & Mike Collins (2009). Biochar Application to Soil. In J.
Lehmann & S. Joseph (Eds.). Biochar for Environmental Management: Science and Technology (1 ed., pp. 207-226). London: UK.
Earth scan.
3. Bd Tai nguyen va Mdi hirong (2010). Bao c^o mdi tnidng Qudc gia nAm 2010 - Tdng quan mdi trudng Vi$t Nam.
4. Cayuela M. L, L van Zwieten, B. P. Singh, S.
Jeffery, A. Roig, & M. A. Sanchez-Monedero (2013).
Biochar's role in mitigating soil nitrous oxide emissions: A review and meta-analysis. Agriculture, Ecosystems and Eniironment, 191, 5-16.
5. Chan K. Y., L. Van Zwieten, I. Meszaros, A.
Downie, & S. Joseph (2007). Agronomic values of greenwasle biochar as a sod amendment Austraban Journal of Soil Research. 45. 629-634.
6. Chen B.. Z. Chen. & S. Lv (2011). A novel magnetic biochar efficienUy sorbs organic pollutants and phosphate. Bioresoun'e Technology. 102{2), 716-723. doi:10.1016/j.biortech.2010.08.067.
7. Chia Cliee H.. Bhupinder Pal Singh, Stephen Joseph, Ellen R. Graber. & Paul Munroe (2014).
Characterization of an enriched biochar. Journal of Analytical and Apphed Pyrolysis, 108,26-34.
8. Clough Tim, Leo Condron, Claudia Kammann,
& Christoph Miiller (2013). A review of biochar and soil nitrogen dynamics. Agronomy, J(2), 275-293.
9. Downie Adriana, Alan Crosky, & OPaul Munroe (2009). Chapter 2: Physical Properties of Biochar. In J. Lehmann &J. Stephen (Eds.). Biochar for Environmental Management: Science and Technology- (1 ed.. pp. 13-32). London, UK- Earth scan.
10. Du an hd trp ndng nghiep cac bon thap tLCASP) (2015). Chien lupc nghien cdu dinh budng cac boat ddn.tr nghien cihi ve quan ly chat thai ndng nghiep thdng mmh, bao ve nidi trudng va chdng bien
ddi khi bau. Bp Nong nghiep va Phat trien nong thon.
11. Joseph S., & P. Taylor (2013). Leading Biochar .Academic with extensive international expenence Russell Burnett: Local Commercial Producer of Biochar based near Bendigo. Paper presented at the BREAZE Biochar Workshop - Ballarat, Ballarat, Victoria.
12. Le Thi Nhung (2015). Danh gia nhu cau dao t^o nghd sd dung phd phu pham ndng nghidp va san xuat ndng nghiep cac bon thap. Dii an hd tn^ ndng nghiep cac bon thap (LCASP).
lutp://lcasp.org.vn/upIo_ads/kien-
tiiuc/J>Qi7_04/L3Ji6334427781125(Lb£dgTnhuiaur dtflii-l.pdf.
13. Lehmann Johannes, & Stephen Joseph (2009). Biochar for Environmental Management an introduction. In J. Lehmann & S. Joseph (Eds.), Biochar for Environmental Management Science and Technology t^^. 1-12). London: Earthscan.
14. Lehmann Johannes, Matthias C. Rillig, Janice Thies. Caroline A. Masiello, Wilham C. Hockaday &
David Crowley (2011). Biochar effects on soil biota - A review. Soil Biology & Biochemistry, 43, 1812- 1836.
15. Mai Thi Lan Anh, Stephen Joseph, Nguyen Van Hidn, Tran Manh Hiing, Nguydn Cong Vinh, Ngo Thi Hoan, Pham Thi Anh (2012). Danh gia chiit lupng than sinh hoc san xuat tir mpt sd loai vat lieu hiru CO phd bidn d mien Bdc Viet Nam. Tap chi Khoa hoc va Cdng nghe, 231-236.
16. Nguydn Cong Vinh, Nguydn Van Hien, Mai Thi Lan Anh, Johan Lehmann. Stephen Joseph (2014). Biochar Treatinent and its Effects on Rice and Vegetable Yields in Mountainous Areas of Northern Vietiiam. International Journal of Agricultural and Soil Science, 2{X), 5-13.
17. Nguyen Dang Nghia (2014). Vai trd cua tiian sinh hoc Oyiochar): San xuat va dng dung hieu qua tiian sinh hoc Trung tam Thong tin Khoa hpc va Cong nghe tiianh phd Hd chi Minh.
18. Nguyen Dang Nghia, Luong Hong Son (2017). ling dung tiian sinh hoc va phan hiru co khoang die he inoi trong canh lac cay ca phe che tai Dak Nong.
N O N G NGHIEP VA PHAT TRIEN N O N G THON - KY 1 - THANG 9/2019
KHOA HOC CONG NGHE
19. Tran Thi Tii, Morihiro Maeda, Le Van 20. Vu Thi Mai. Trinh Van Tuyen (2016).
Thang. Traji Dang Bao, Nguydn Dang Hai Thuyen Nghien ciiu kha nang xir ly amoni hong moi huong (2013). Nghien ciiu sii dung tiian sinh hoc tir vo dira nude cua than sinh hpc tii loi ngo bidn tinh bang bon cho rau Komalsuna hen mdt so loai ddt d tinh HjPOj va NaOH. Tap chi Khoa hoc - Dai hoc Qudc Thira Thien - Hue. Tap chi Khoa hoc va Cdng nghd, gia Ha Nor Cac Khoa hoc Trai dat va Mdi tiudng, 32,
Vidn Han lam Khoa hoc va Cdng nghe Viet Nam, Ha 274-281.
NQI, 51 315-322.
BIOCHAR AND ENHANCED-BIOCHAR: A REVIEW
Nguyen Thi Thu Nhan\ Nguyen Khac Linh^
'Hanoi University of Natural Resources and Environment Summary
Biochar is a product of biomass pyrolysis in anaerobic conditions. In the fields of environment and agriculture, biochar has been widely used and studied; in which many authors have observed llie benefits of this material for the environment, soli properties and crop yields. However, conventional pure biochar has many limitations in improving crop yield. This review article briefly introduces the production process, agronomic benefits and limitations of biochar when used in agriculture. Also, the article analyzed and proposed a demand of a nutritionally enhanced-biochar complex and suggests production methods for this product. Some melliods lo make this product are (i) torriiicaUon of biochar mixture and other materials {e.g. clay, rock, minerals), (li) pre-pyrolysis (slow pyrolysis of biomass with a mbcture of minerals and nutnents at low temperatures of 350-450°C), (iii) post-pyrolysis OJiochar and mineral/nutnlion/fertilizer are activated by heal or chemicals such as acids, bases), (iv) composUng biochar with organic materials such as manure, green manure etc. With abundant biomass resources, Vietnam has great potential to develop enhanced biochar for agricultural production..
Keywords: Enriched biochar, biochar, carbon, pyrolysis.
Ngudi phan bifin: PGS.TS. Pham Quang Ha Ngdy nhan bdi: 4/7/2019
Ngdy thdng qua phan bifin: 5/8/2019 Ngdy duyet dang: 12/8/2019
