7(ip chi Khoa hgc Tru&ng Dai hgc Cdn Tha Phdn B .\'dng nghiep. Thuy san vd Cdng nghe Sinh hgc 26 aOBi: 43-49
Tap chl Khoa hpc TrircJng Oai hpc Can Thd website: sj.ctu.ecJu.vn
BIEN PHAP CAI THIEN DO PHI NHIEU DAT VA NANG SUAT LUA TREN D A T P H U SA CO THAM CANH LUA TAI HL"VEN MOC HOA - TINH LONG AN Tran Ba Linh'. Vd Thi Guang'. Biii NTiuan Dien' va Ngd Nggc Hung'
Bd mdn Khoa hgc Ddt, Khoa Xong nghiep va Sinh hgc Cng dung Trudng Dgi hgc Cdn Tha Thong tin chung:
Ngaynhdn: 08/11 2012 Ngdy chdp nhdn • 20/06 2013 Tide:
Improvement of soil fertility and rice yield on old alluvial soil at Moc Hoa districi.
Long An province Tir khda:
Ddt phit sa cd. phdn hdv ca.
lum canh liia - mdu. duang chdt ddt trdng Keywords:
Old allm'ial soil compost amendment, rice-cash crop alternation, soil nutrients
ABSTRACT
In the Mekong delta, old alluvial soil types are poor in soil nutrients.
Famers have applied only inorganic fenilizers for double nee cultivadon and have not paid much attention on using organic manure. With high dose of inorganic N and P applied, intensive rice cultivation has led to soil degradation and low rice yield. Objectives of (his study were lofrnd the wa}> to improve soil fertility and rice yield of mono-rice sysiem on old allm'ial soil in Moc Hoa district. Long .-in province. Treatments were arranged in randomized complete block design with 1) Double nee crops (as farmers' practice). 2/ Double rice plus 10 tons (T) of compost, 3) Rice alternated M ith sesame:4) Rice alternated with peanut: 5) Rice alternated with soybean. Experiment was conducted for 8 years. Results showed that the system of rice crop alternated with cash crop led to increase signifrcantly soil available nitrogen, labile carbon content and nitrogen mineralization in comparison with traditional rice cropping practice. Organic amendment result the increases of labile carbon and available nitrogen in soil compared to the rice treatment Milhout compost addition. As consequence, the nee yield has been improved by either compost amendment or alternative cropping of rice and upland crops.
TOM TAT
O ddng bdng sdng Cuu Long, thdm canh lua trong nhieu nam dua den bac mdu ddt. Tren ddt phii sa cd. Id bieu logi ddt ngheo duang chdt. ndng ddn canh tdc dgc canh lua hai i-u khdng bdn phdn hint ca. chi sir dung phdn I'd ca vdi htang dgm (Xj vd ldn (P) cao, ndng sudt liia dgt thdp. Thi nghiem ludn canh lua — mdu, bdn phdn hihi ca dugc thuc hien trin ddt phit sa cd tgi huyin Mgc Hda - tinh Long An nhdm ddnh gid sw cdi thiin hdm luang duang chat trong ddt vd cai thiin ndng sudt lua. Tin nghiein duac bd tri theo khdi hodn todn ngdu nhien gdm ndm nghiim thirc: (1) liai vu liia (theo canh tdc ciia ndng ddn), (2) lua + 10 tdn phdn hdu ca vi sifjf, — liia, (Sl Ida - me. (4) lua — dgu phong (5j liia — ddu ndnh. Kit qud thi nghiim ddi hgn qua S nam cho thdy ludn canh lua - mdu giiip tdng khd ndng cung cdp dgm hint dung trong ddt, tang khd nang khodng hda dgm, tdng lidm lugng cacbon di phdn huy so vdi chuyin canh Ida. Bdn phdn hihi ca giiip cdi thien hdm lugng cacbon de plidn huy. tang lugng dgm hOu dung trong ddt cdy nghia. Qua hiiu qud cai thien do phi nhiiu ddt. ndng sudt lua cua nghiem thirc ludn canh lita - mdu vd nghiem thuc canh tdc hai vu lua cd bdn phdn hdu ca cao hem khdc biet cd y nghTa thdng ke so vdi thdm canh lua theo biin phdp kp thugt cua ndng ddn
Tgp chi Khoa hgc Tni&ng Dgi hgc Cdn Tha Phdn B .Xdng nghiep. Thin san vd Cdng ngh^ Smh hgc: 26(2013). 43-49
1 M O D A U
Nhieu vu liia dugc canh tac trong nam va tham canh liia nudc la giai phap hieu qua dap irng nhu ciu luong thyc trudc ap lyc gia tang dan sd thi gidi (01k vd ct\:, 2002). Hien tai, cac he thong tham canh liia nudc chiem hai den ba vu trong nam vdi dien tich khoang 14 trieu ha d cac nudc dang phat trien ciia Chau A da gdp phan ldn vao san lugng liia gao ciia toan cau (Cassman vd ctv., 1995; Mahieu vd ctv., 2002). Tuy nhien, su suy giam nang suat Ilia hien nay trong nhieu thf nghiem tham canh dai han ttr 20 den 30 nam qua da dat ra sy nghi ngd ve tinh ben vung ciia he th6ng nay (Cassnrian va ctv., 1997; Oik vd ctv., 1996).
Mgt sd vimg suy giam nang suat lua the hien rd qua tang dau tu su dung phan vd co va thudc bao ve thuc vat de duy tri nang suat lua.
Vdi viec canh tac liia ddc canh lien tuc neu khong cd nhirng bien phap canh tac hgp ly, v l lau dai sg anh hudng den tinh ben vung ciia san xuit ndng nghiep. Do do, cin phai xac dinh md hinh canh tac thich hgp, tim ra nhilu bien phap de cai thien do phi nhieu dit, cai thien nang suat iua. Qua do ndng dan cd thi chgn lya bien phap thfch hgp vdi dieu kien canh tac, kha nang tai chinh va nhat la thj trudng tieu thu san pham.
Trong dieu kien ngap nudc lien tuc ciia he thdng tham canh liia nudc, su phan huy yim khf du thira thyc vat lam ban chl kha nang khoang hoa dam tir cac thanh phan mim ciia chat hihi co trong dit (Oik va Cassman, 2002).
Dam (N) hiiu dung bj kilm giii dudi dang tao thanh cac hgp chat hiiu ca khd phan hiiy d dat Iua ngap nudc cao han so vdi trong dit thoang khi (Ponnamperuma. 1976; Dobermann va Fairhurst. 2000). Sy khoang hoa chat hiiu CO va sy bit dpng dam do cac ylu to khong sinh hgc tao thanh cac hgp chit hiru co kho phan huy d dat ngap nudc cao hon dit thoang khi (Borthakur va Mazunda. 1968). Moi trudng khii lien tuc do canh tac liia nhilu vu trong nam. lugng chit him co d l phan hiiy c6 the giam dan din giam kha nang cung cip dam hiru dung (Stevanson et al., 19^86). Dong tlidi se lam cho he vi sinh vat dit thay ddi nhu:
giam da dang loai va giam mat sd vi sinh vat.
Tir dd, nang suat cay trdng giam, hieu qua kinh t l mang lai khdng cao (Vd Thi Guong, 2001).
Nghien ciiu dugc thyc hien nham cai thien do phi nhieu dat va nang suat liia cua viing san xuit Ma dgc canh tren dat phii sa cd theo hudng san xuat liia ben vung.
2 PHU'ONG PHAP N G H I E N C i r u Dgc tinh ddt thi nghiem
Dit thf nghiem la loai dat phii sa cd (Plinthosols) cd pH trong khoang 4,7 thupc loai dat chua vira. Dat cd ham lugng chat hihi CO ngheo (2,18%). Kha nang trao ddi cation (CEC) thap. Dat ngheo dam tdng sd, ham lugng cation bazo trao ddi rat thap. Dung trpng ting mat kha cao, cho thiy dat cd khuynh hudng hi nen de. Ham lugng Fe^Os tu do va Al^" trao doi trong dat cao (Bang 1). Nhihig linh chat hoa, ly tren cho thay dat cd do phi nhieu tliap va cSn cd nhiing bien phap c^i thien de nang cao do phi nhieu va nang suit cay trdng.
Bang 1: Mpt so chi tieu faoa hpc ciia dat tfai nghigm
Chi tieu Gid tri
P H H 2 0
CEC(meq/]00g) Chat huu ca {%) N,inB=6 (%) K^(meq/100g) Ca^^(meq/I00g) Mr''(meq/100g) Na'(meq/100g) Dung trpng (g/m^) Dp xop (%) Fe203 (%) Al-'^ (meq/lOOg)
4,7 3,75 2,18 0,154 0,08 0,48 0,60 0,06 1.32 43 2,84 2,53 Thf nghiem ddng rudng dugc thyc hien dai han tu nam 2001 din nam 2008 tai xa Binh Tan, huyen Mgc Hda, tinh Long An, theo thi thiic khdi hoan toan nglu nhien gdm nam nghiem thiic va bdn lin lap lai vdi dien tfch 64 m ' cho moi Id thi nghiem, gdm cac md hinh canh tac nhu sau;
Nghiem thirc 1: Liia Ddng Xuan - Liia He Thu (theo canh tac cua ndng dan)
Nghiem thirc 2: Liia Ddng Xuan + 10 tan/ha phan him co vi sinh - Lua He Thu
Dau
Tap chi Khoa bgc Tnr&ng Dgi hgc Cdn Tha Nghiem thirc 3: Lua Ddng Xuan He Thu
Nghiem thirc 4: Liia Ddng Xuan - phdng He Thu
Nghiem thiic 5: Liia Ddng Xuan - Dau nanh He Thu
Sau 8 nam thyc hien thf nghiem, mau dat dugc lay theo nghiem thuc vao cudi vu lua Ddng Xuan, ngau nhien tai nhieu vi tri tren timg Id d do sau 0 - 2 0 cm, sau dd trdn deu, mang ve phdng thi nghiem phoi khd ty nhien trong khdng khi, nghien min de phan tfch dam hiru dung, chat hiru co trong dat, carbon d l phan buy. Kha nang khoang hda dam dugc phan tich tren mlu dat tuoi. Nang suat lua thf nghiem dugc thu thap vao cudi vu liia Ddng Xuan.
Phuang phap phdn tich: Chat hiiu co trong dat dugc xac dinh bang phuang phap Walkley- Black. Cacbon de phan huy dugc phan tich bang phuong phap chuan do. dam ammonium (N-NHi"), dam nitrate (N-NO3') va ham lugng dam mau dat li khoang hoa dugc xac dinh bang phuong phap so mau.
So lieu thf nghiem dugc dugc -K\I ly bang chuang trinh Excel va phan tfch thdng ke bang chuang trinh MSTATC de so sanh trung binh cac nghiem thiic d miic y nghia 5%.
3 K E T QUA VA THAO LUAN 3.1 Ham lugng dam (N)hiru dung trong flat
Kit qua phan tfch dugc trinh bay d hinh 1 cho thiy dam hihi dung trong dit d cac nghiem thiic luan canh liia - mau bien ddng tir 21,2 - 23.9 mg/kg dit cao ban va khac biet cd y nghia thong ke so vdi nghiem thirc dgc canh liia (17.7 mg/kg dit). Ci cac nghi#m thuc luan canh Ilia - mau, dit cd thdi gian thoang khf khi dugc canh tac vu mau. da giiip vi sinh vat hieu khi trong dit cd dilu kien sinh trudng va phat triln gdp phin lam tang kha nang khoang boa dam. do dd lam tang ham lugng N hiiu dung trong dit. Ddng thdi, nghiem thiic tham canh lua cd bdn phan hiru ca cung cd lugng dam
Phdn B Ndng ngluip. Thuy san vd Cong ngbe Sinh hoc. 26 (2013/ 43-49 hiru dung cao han so vdi chuyen canh liia. Ket qua nay cd the dugc giai thich la do bdn phan hihi CO da lam tang dam hiru dung tir su phan hiiy hao khi cua cac hgp chat hiru ca (Nyle et al, 1999).
Lda-LOB t a a < 1 0 » i Uta-M6 LOa-Oau t a a - 0 4 u H C - l i i a PMng N M i
M6 hinh canh tac
Hinh 1: Dam fairu dung trong dat giira ckc ngfaiem thuc tfai ngfaifm 3.2 Kha nang khoang hda dam (N) 3.2.1 Hdm luang N'NHi
Kha nang khoang hda N-NRt"" trong dieu kien u thoang khi cac mlu dat dugc thu d cac md hinh canh tac cho thay d thdi diem ban dau thi Iugng N-NH4" ciia cac nghiem thuc luan canh lua-mau cao hon so vdi cac nghiem thuc doc canh Iiia cd va khdng cd bdn phan htm ca (Hinh 2). Kit qua nay dugc giai thich la do tien trinh ammonium hda chuyen dam hiru ca thanh N-NH4" ban dau diln ra manh ban d cac nghiem thirc luan canh liia-mau so vdi cac nghiem thiic ddc canh liia. Sau 2 tuan ii ham lugng N-NH4" tang dan d hai nghiem thuc ddc canh lua va nghiem thuc doc canh liia cd bdn phan hiiu co. Trong khi dd, cac nghiem thirc luan canh lua-mau cd ham lugng N-NHt" cd khuynh hudng giam. Sau tuan 4 va tuan 8 ham lugng N-NH4* giam di manh ban va khac biet cd y nghia thdng ke d cac nghiem thiic luan canh lua-mau va ddc canh Iua cd bdn phan hiiu ca so vdi nghiem thuc dgc canh liia. Ket qua na; cd the do ham Iugng chat huu co da giam do qua trinh khoang hoa. Mat khac, do dieu kien thoang khi mdt lugng ldn amonium da chu}'en thanh nitrate.
Tap cbi Kboa hgc Tnr&ng Dai hoc Cdn Tha PhdnB-Ndng nghiep. Thtry san vd Cdng ngh? Sinh hgc: 26 (20131 43-49
Hinfa 2: Ham luong N-NH/ trong dit qua cac tuan u
60 - 50
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3.2.2 Hdm lugngN-XOi
Ham lugng N-NO3' ciia cac he thdng cay tr6ng tang Ien qua cac tuan ii (Hinh 3) la do hoat ddng ciia vi sinh vat trong dieu kien thoang khi da oxy hda mdt lugng ldn N-NHj^
thanh N-NO3'. Lugng N-NO3' tang nhanh hem
khac biet cd y nghia thdng ke d cac nghiem thirc liia-dau nanh va dau phdng so vdi cac nghiem thuc cdn lai la do luan canh cay mau da tao dilu kien thoang khi cho dat, thuc diy sy phat triln cua cdng ddng vi sinh vat hao khf.
Hinh 3: Him lugng N- NO3' trong dat qua cac tuan ii
Lua - Lua Lua-^loUnHC-LOa . L u a - M i L u a ' 0 ^ J Phdng Lua-Oau Ndnh
2 tu^n 4 tuin Thiti gian u
3.3 Ham lugTig chat huu ca trong dat Kit qua phan tich cho thay ham lugng chit hihi ca trong dat bien ddng tir 2,14-2,8%
(Hinh 4) Dat cd ham lugng chat hiiu ca thap va deu d muc ngheo. 6 nghiem thuc tham canh Iua cd ham lugng chat hiiu co cao hon khac biet cd y nghTa ve mat thdng ke so vdi cac nghiem thiic luan canh liia •- mau. Kit qua nay la do d nghiem thiic tham canh lua sau mdi vu thu hoach Iiia. gdc ra dugc viii Iai trong dat Iam gia tang ham lugng chit him co. Mat khac. d cac nghiem thirc luan canh liia mau.
dat cd thdi gian thoang khi, tao mdi trudng oxy hda thuc day qua trinh khoang hda chat hiiu ca. Nghiem thuc tham canh liia co bdn phan hiiu CO CO ham lugng chit hiiu co thap han khac biet cd y nghia thdng ke so vdi tham canh liia, dieu nay cd the dugc giai thich la do phan huu CO vi sinh dugc bdn da cung cap chiing nam Trichoderma vao dat. Chiing nam nay giup qua trinh phan hiiy va khoang hda ram ra dien ra tdt hon so vdi nghiem thiic tham canh Ilia khdng cd bdn phan hiiu ca vi sinh.
Tap chi Khoa hoc Tnrdng Dai hoc Cdn Tho Phan B Song nghiep. Thuy san \a Cong nghe Sinh hoc 26 (2013i. 43-i9
Hinh 4: Chat hiru ca trong dat giua cac nghiem tbirc thi nghidm
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3.4 Cacbon de phan hiiy
Ket qua phan tich ham lugng cacbon de phan buy dugc trinh bay d hinh 5 cho thiy mac dil nghiem thiic tham canh liia cd ham lugng chat hiiu ca trong dat cao hon cac nghiem thuc luan canh va nghiem thuc tham canh cd bon phan hiiu co (dugc trinh bay d hinh 4), tuy nhien ham lugng cacbon de phan buy cua nghiem thiic tham canh lai thap hon cd y nghia thdng ke so vdi' cac nghiem thiic cdn lai. Ket qua nay cd the dugc giai thich la do d dat tham canh lua ngap nudc lien tuc gan nhu d trang thai khir, thieu oxy, hoat dpng ciia vi sinh vat kem nen lam cham kha nang phan buy cac du
Mo hinh canh tac
thua thuc vat. Mat khac, trong dat ngap nudc lien tuc, chat huu co hien dien d cac dang hgp chat kho phan buy han so vdi dat luan canh lua - mau. Tuang ty, ham lugng cacbon de phan huy trong he thdng tham canh lua cd bdn phan hdu CO cao han khac biet cd y nghia thdng ke so vdi nghiem thiic tham canh liia. Dieu nay cd the dugc giai thich la do bdn phan hdu co hoai muc da cung cap thanh phan cacbon de phan buy cho dat. ngoai ra bon phan hiru ca cdn giup tang cudng he vi sinh vat va tao dieu kien tdt de vi sinh vat Uong dat hoat ddng lam gia tang ham Iugng cacbon de phan hiiy.
Hinh 5: Ham lirong cacbon d l phan hiiy trong dat
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Tgp chi Khoa hgc Tnrang Dai hgc Cdn Tha 3.5 Nang suat lua
Kit qua thi nghiem cho thiy nang suit d cac nghiem thuc luan canh lua-mau cao ban khac biet cd y nghia thdng ke so vdi nghiem thuc tham canh lua (Hinh 6). Khi luan canh liia - mau, dit CO thdi gian dugc phoi khd, thoang khi giiip phan huy chat him co trong dat thuan lgi cung nhu tao mdi trudng cho cac vi sinh vat boat ddng lam gia tang ham Iugng cacbon de phan huy va khoang boa dam. tang ham Iugng dam hiiu dung trong dat dua den nang suat cua he thong luan canh lua — mau cao hon
Phdn B: Ndng nghiip. Thuy san vd Cdng ngh? Sinh hgc: 26 (2013): 43-49 so vdi chuyen canh lua. Ket qua nay phu hgp vdi nghien ciru ciia DobenuMn vd ctv (2000), trdng Ilia sau vu mau thudng cho nang suit cao ban so vdi trdng liia tham canh.
Ben canh dd, nang suat d nghiem thuc tham canh cd bdn phan huu co vi sinh cao hem khac biet cd nghia thdng ke so vdi nghiem thiic tham canh. Do bon phan hiiu co giiip nang cao ham lugng chit hihi co de phan huy, tang hieu qua su dung phan vd co, dam hiJu dung va hoat ddng ciia vi sinh vat dat.
Hinfa 6: Nang suat lua thuc te giira cac nghiem thuc
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1 0
Lua-Lua Lua+^IOlai L u a - M e L l i a - € ) a i L u a - D a u h C - L u a Rigng Nanh
M6 hinh canh tac 4 KET LUAN
Kha nang cung cap dam hiru dung, su khoang boa dam va ham lugng cacbon de phan buy trong dat d cac nghiem thuc luan canh liia - mau va nghiem thiic canh tac hai vu liia cd bdn phan hihi co vi sinh cao hon so vdi nghiem thuc chuyen canh liia khdng bdn phan hiiu CO. dieu nay din den tang nang suit liia d md hinh luan canh liia - mau va chuyen canh liia cd bdn phan hiiu ca so vdi ddc canh liia.
TAI LIEU THAM KHAO
1. BorthakurH. P. andN. N. Mazunda, 1968.
Effect of lime on niuogen availability in paddy soils. J. Indian Soil Sci. Soc, 16:143-147.
2. Casaman. K.R. A. Dorbermann. P.C. Stacruz, G.C Gines, M.I. Samson. J.P.Descandota, J.M Alcatara. M.A Dizon and D.C Oid. 1995. Soil organic matter and the indigennous nitrogen
supply of intensived rice system in the tropics.
Plant and soil.
Cassman K. G.. G. C. Gines, M. A. Dizon, M.
I. Samson and J. M. Alcantara, 1997. Nitrogen use efficiency in tropical lowland rice systems:
Contributions from indigenous and applied nitrogen, Field Crops Res. 47,1-12.
Dobermann A. and C. Witt, 2000. The potential impact of crop intensification on carbon and nitrogen cycling in intensive rice systems. In: Kirk, G.J.D., D.C. 01k, (Eds), Carbon and nitrogen dynamics in Flooded Soils. Intemational Rice Research Institude, Philippines, pp. 1-25.
Mahieu N., D, C. 01k and E.W. Randall, 2002.
Multinuclear magnetic resonance analysis of two humic acid fractions from lowland rice soils, J. Environ, Qual. 31 : 421-430.
Nyle, C. Brady, Ray, and R. Weil, 1999.
Properties and Management of Soils in the Tropics. Prentice Hall.
Tap chi Kboa hgc Tnr&ng Dgi hgc Can Tha Phdn B Ndng nghiep. Thuy san vd Cdng ngbe Smh hoc. 26 (2013). 43-49 Oik D. C. and K. G. Cassman, 2002. The role
of organic matter quality in nitrogen cycling and yield uends in intensively cropped paddy soils, p. !355-l tol355-8. In Proc. 17th Worid Congress of Soil Science. 14-21 Aug. 2002, Bangkok, Thailand, Intemational Union of Soil Sciences.
Oik D. C , K. G. Cassman, E. W. Randall, P.
Kinchesh, L. J. Sanger and J. M. Anderson, 1996. Changes in chemical properties of organic matter with intensified rice cropping in tropical lowland soil, European Joumal of Soil Science, 47. 293-303.
Oik D, C, K. G. Cassman, N. Mahieu and E.W.
Randall, 2002. Conserved chemical properties of young humic acid fractions in tropical lowland soil under intensive irrigated rice cropping, European Joumal of Soil Science.
49, 337-349.
10. Ponnamperuma F. N., 1976. Specific soil chemical characteristics for rice production in Asia, IRRI Res. Paper Ser. 2:18.
11. Stevenson, F. J., 1986. Cycles of soil. John Wiley and Sons, Inc. 1984-1996.
12. Vo Thi Guang va J.C Revel, 2001. Danh gia kha nang cung cap dudng chat cua dat lua viing dong bing song Cuu Long. Hpi Khoa hpc Dit Viet Nam. Tap chi Khoa hpc Dit 15, trang 26-32.
