CHO CAY NGO LAI O TRA VINH

Phan thuf hai Dinh dudng dat va phan bon QUAN LY DINH DITONG THEO VUNG CHUYEN BIET. CHO CAY N G O LAI O TRA VINH N g u y i n My Hoa Dang Duy Minh Phan Thanh B^ng^ LGim THIEU Viec khuyin cao bon phan cho cac loai cay trdng va cho ngo trudc day thudng dua vao cac thi nghiem phan bon, hoae du'a vao phan tich d i t de khuyin cao phan bon cho nhCpng viing rong lo-n; dac tinh dp phi nhieu khac nhau ciia tii'ng canh ddng do e h i do bon phan va phuang phap canh tac khac nhau da khong dugc chii y d i n . N h i m xay dij'ng chiin luge v i bon phan dam, lan va kali hieu qua cho tii'ng viing chuyen biet tiiy theo d i i u kien d i t dai va khi hau cu t h i , nong dan cd t h i ap dung dugc, Vien Dinh duang Cay trdng Qudc t i IPNI (International Plant Nutrition Institute) phdi hap vdi mgt so Vien, Trudng 6' Viet Nam nghien eifu thif nghiem phuang phap quan ly dinh duang theo viing chuyen biet SSNM (SiteSpecific Nutrient Management) cho cay ngd lai vdi muc tieu la quan ly c h i t dinh duang hieu qua theo nhu c i u cua cay d i gia tang nang s u i t va lai nhuan 6' nhi/ng viing trdng ngo chu y i u cua Viet Nam. Bai bao cao nay n h i m thdng tin ve mgt sd ly luan ciia phuang phap, cac k i t qua budc d i u v i nghien cifu xay dung phuang • phap quan ly dinh duang theo viing chuyen biet cho cay ngo lai d Tra Vinh.. Bu'O'C 2: ly&c lu'O'ng SIF dap irng nang s u i t ciia cay trdng ddi vo'i phan dam, phan lan va phan kali Su dap ifng nang s u i t cua cay trdng ddi vdi tii'ng nguyen td dinh duang khao sat la su khae biet giii-a nang su§t dat dugc trong d i i u kien tdi hao, bon du phan dam (N), phan lan (P), phan kali (K) va cac c h i t dinh du&ng khae duo-c eung c i p day du (NS-NPK) va nang suat 6 Id khong bon c h i t dinh duang khao sat. Nang suit dat duac a Id khong bon phan N (NS-ON), khong bon phan P (NS-OP), va khong bon phan K (NS-OK) duac djnh nghla la nang suat dat duac a 16 khong bon N, P, K theo thu tu nhung bon day du cac duang c h i t khae. Do do, dap ifng nang suat cua cay trdng ddi vdi phan N, P, K duac xac dinh la hieu sd (NS-NPK) - (NS-ON), (NS-NPK ) - (NS-OP), va (NS-NPK) - (NS-OK), theo thif tu. Birac 3: Xac djnh lu'O'ng phan bon N, P va K dica vao sir dap irng cua nang s u i t v 6 i phan bon, hieu qua nong hoc va can b i n g dinh du'O'ng trong d i t .. 2. TOM TAT NGUYEN LY CUA PHUOTNG PHAP QUAN LY. Hieu qua nong hoe (Agronomic efficiency) cua phan N (AEN, kg hat gia tSng/kg phan N bdn) duac tinh dua vao dap ung nang suit vdi phan dam va luang phan N bon theo cong thii'c:. CHAT DINH DUONG CHUYEN VUNG. A E N = (NS-NPK - NS-ON)/luang phan N bdn. Theo Witt (2007), phuang phap duac tien hanh gdm 5 budc:. Hieu qua nong hgc cua phan P va phan K duac tinh tuang tu:. Bu'O'C 1: Xay d y n g nang s u i t muc tieu. AEp = (NS-NPK - NS-OP)/lugng phan P bon. Nang suit muc tieu dugc djnh nghla la mipc nang suit a 80-90% nang suit tiim nang va la nang suit trung binh cao nhit trong vdng 3-5 nam ma nguai ndng dan cd t h i dat dugc trong dieu kien canh tac tot nhat. Nang suit nay co t h i bien dong tiiy theo miia vu va tiiy theo canh ddng.. A E K = (NS-NPK - NS-0K)/lugng phan K bdn. ' Bo mon Khoa hoc Dat & Quan ly D§t dai, Khoa nong nghiep & Sinh npc Lfng dgng, Tru'dng Ogi hpc Can Tha. 20. Sau do, luang phan N c i n bon duac udc luang dua vao dap ii-ng nang s u i t vdi phan bon eiia cay trdng va hieu qua nong hoc eiia phan N theo nguyen t i e dap ifng nang suit thip, hieu qua nong hoc t h i p bon luang phan N til" thap d i n trung binh so vai truang hgp su dap ung nang suat cao, hieu qua nong hoe eao, bdn lugng N tie trung binh den cao. Ben canh. dd can k i t hgp sic dung bang so mau la de d i i u ehinh lygng phan N phii hgp vdi nhu cau cua cay trong Lugng phan P va K e i n bdn eung dugc udc luang dua vao nang suit muc tieu, dap ipng nang. suit va nhu c i u dinh duo'ng cua cay trdng Dua vao k i t qua nghien cifu, Witt (2007) da d i nghj bang hudng d i n lugng phan NPK e i n bdn eho cay ngd d Viet Nam (Bang 1.2 & 3).. Bang 1. Lugng phan N de nghj cho cay ngd lai d Viet Nam dua vao eae mii'e dap u-ng nang suit va hieu qua su" dung phan bdn. (Nguon: Witt, 2007). Dap ifng nang s u i t ddi vdi phan N (t^n/ha) ->. Thap (2-4 tlin/ha). Trung binh (4-5 tan/ha). Cao (5-7 tIn/ha). Hieu qua nong hpc (kg nang suat gia tang/ kg phan N) -^. Thap (25 kg/kg). Trung binh (29 kg/kg). Cao (33 kg/kg). Dap u'ng nang suat khi bon dam (tan/ha) i 1 2 3 4 5 6 7 8. 1. Mifc phan dam bon (kg/ha). 80 120 160. 105 140 175. 120 150 180 210 240. 1. Bang 2. Lugng phan P du kiin de nghi cho cay ngd lai a Viet Nam dya vao cac mii'e dap u'ng nang suit va hieu qua sir dung phan bdn". {Nguon: Witt, 2007) 5 - 8 tan/ha. Nang suat muc tieu (t/ha) —> Dap ifng nang suat ddi vdi phan lan (tin/ha) i 0 0.5 1.0 1.5 2.0 25. 9-12t§n/ha. Lu'O'ng phan lan can bon (kgP205/ha) 5 - 10 25-30 45-50 65-70 85-90 105- 110. 10- 15 30-35 50-55 70-75 90-95 110- 115. ''Bang nay du'O'c xay du'ng di/a vao su' u-ac lu'O'ng lu'O'ng lan can bon de gia tang 1 tan nang suat la 40 kg P:0=, (hieu qua nong hoc ciia P la 57 kg hat/kg P, va 20% cin hoan tra lai do iup'ng P bj lay di bdi cay trdng Bang 3. Lugng phan K du kien de nghj eho cay ngd lai a Viet Nam dua vao cac miic dap U'ng n§ng suit va hieu qua sir dung phan bdn^'. {Nguon: Witt, 2007) Nang suat mgc tieu (tan/ha]^-> Dap img nang suat vdi phan kali (tan/ha) 40 0.5 1.0 1.5 2.0 2.5. 7 - 1 0 tan/ha | 1 0 - 1 2 tin/ha 4 - 7 tan/ha Lu'png phan kali can bon (kgK20/ha) 30-40 1 40 - 50 20-30 60-70 50-60 40-50 80-90 70-80 60-70 100- 110 9 0 - 100 80-90 120-130 110- 120 100- 110 130-140 140-150 120-130. j i. ''Bang nay du^pc xay du'ng du'a vao sg- uac lu'png lu'O'ng K c§n bon de gia tang 1 tan nang su4t la 40 kg K2O (hieu qua nong hoc ciia K la 30 kg h9t/kg K, va 20% can hoan tra Igi do lu'cyng K du^ac lay di bdi cay trong Bu'O'C 4: B6n phan N theo nhu c i u dinh du'O'ng ciia cay & cac giai doan quan trong. Cae giai doan sinh trudng va luo'ng phan N d i nghi bdn eho cac giai doan duoc trinh bay d Hinh 1.. 21. VE. v;.. y. '1^. V3. V7. bip/ha VO. VIO. VT. Hang hat/bap V6-8. VI0-12. t-\r. '->/. R6. RI. hat/hang. Trona lifcyna hat. V14-VT. cm I—I 30%N. ta35%N 13 35% N H. Bdn bo sung 15% phan ure neu LCC<4. +15% N. Di§u chinh bon phan dgm a giai doan V8-VT. l-linh 1. Cae giai doan sinh trudng va lugng phan N de nghi bdn cho c^c giai doan (Witt, 2007). VE: giai doan niy mam. V3, V6, V7, V8, VIO, V12, V14: giai doan 3 la, 6 la, 7 la, 8 la, 10 la, 12 la. VT: Giai doan trd cd. R I : Giai doan phun rau. R6: giai doan chin sinh ly. Bu'ac 5: Dieu chinh lircrng phan dam SLH dung b i n g bang so mau la o i tdi uu hda hieu qua su dung phan dam, lugng phan N d eae giai doan sinh truo'ng ed t h i dugc d i i u chinh dya vao bang so mau la LCC (Leaf Color Chart) nhu sau: • N i u gia tri LCC < 4, bdn tang lugng N • N i u gia tri LCC = 4,0 - 4,5, bdn phan N theo khuyin cao • N6u gia trj LCC > 4,5, cd the hoan viec bdn dam vai ngay va so mau la lai ho$c bdn giam luang dam Lugng N bdn dugc d i i u chinh a mii'e bdn them 15% tong luang dam, niu LCC < 4 0 va n i u dap ifng nang s u i t > 4 t/ha.. 3. AP DUNG THi NGHIEM THEN CAY NGO LAI TAI TRA VINH 3.1. Ph)j'0'ng phap thi nghiem Thi nghiem duac thuc hien tai huyen Cau Ke. tinh Tra Vinh trong vu Dong Xuan nam 2006 va 2007 tren gidng CP 888 vdi cac nghiem thuc phan bon khae nhau Thi nghiem bd tn trong nam 2006 bao gdm 4 nghiem thifc, vc'i 5 l i n lap lai thuc hien tren 5 rugng cua ndng dan, d mat do trdng 67 000 cay. 22. 1. 2. 3 4.. NPK (200N - 9OP2O5- 100 K2O) PK (khdng bdn N), (9OP2O5-IOO K2O) NK (khong bdn P), (200N - 100 K2O) NP (khdng bdn K), (200N - 9OP2O5). Trong n§m 2007, thi nghiem dugc tiip tue vdi 4 nghiem thifc tren va dugc bd tri thif nghiem them nghiem thipc SSNM (bdn 200N-50 P2O5-5O K2O o' mat do 72000 cay (60x23 em)), dugc xem la nghiem thice d i nghi dya vao kit qua nghien eifu cua nam 2006). Cae ehi tieu theo doi la nang s u i t thue t i . M i u d i t d i u vu dugc phan tich xac dinh thanh p h i n ea gidi, phan tieh cac chF tieu hoa hgc d do sau 0-20cm: c h i t huu ca theo phuang phap Walkley-Blaek, N tong sd theo phuang phap Kjeldahl, CEC va K trao doi trich b i n g I N NH4-axetat, pH trich bing nude cit, ti le 1:1, lan d i tieu theo phuang phap Bray-2 (0,03 M NH4F + 0,1 M HCI). 3.2. K§t qua va thao luan Cac k i t qua nghien cifu cua de tai dugc trinh bay tren ca so" tong k i t thi nghiem nSm 2006 va 2007, la sd lieu nang s u i t trung binh d cac mat do 67.000 va 72.000 cay. K i t qua phan tich d i t 6' 5 d i i m khao sat cho thiy d i t ed sa c i u chu y i u la set, pH b i i n dgng tif 4,8 den 5,2, CEC kha cao (18-27 meq/IOOg), ham luang caebon hCKU ca tif 1,7-3,8%C, ham luang. N tdng sd duac danh gia a mifC trung binh (0,12-0 18%N), hSm lyang lan d i tieu cao (41-102 mg P/kg), ham luang kali trao doi eao (0,21-0.83 meq K/IOOg) 3.2.1. Nang suit & 16 khong bon phan Kit qua trinh bSy a hinh 2 cho thiy nang suit. trung binh d cac nghiem thuc khdng bdn phan dam dat r i t thip (1-2 tin/ha), trong khi dd d cae nghiem thuc khdng bdn lan va kali nang suit trung binh dat r i t cao 8-9 tin/ha va 7-9 tan/ha, theo thif ty, cho thiy d i t thi nghiem cd kha nang cung c i p dam r i t thip, trong khi dd kha nang cung c i p lan va kali la r i t cao.. Nang su^t (l/ha) ON. OP. OK. Hinh 2. N§ng suit d cae nghiem thifc khdng bdn N (ON), khdng bdn P (OP) va khdng bdn K (OK). Cac diem va thanh doc tren dd thj bieu dien gia tn trung binh va dp lech chuan theo thif ty. eho eae gia trj nSng suit. 3.2.2. Nang suit a nghiem thirc bon phan day du NPK/SSNM ' Kit qua trinh bay d Hinli 3 cho thiy nang suit. trung binh trong diiu kien ed bdn phan d i y du ed the dat tii' 7,5-9.5t/ha. Nang suit muc tieu d Tra Vinh do dd ed t h i la 8-8,5 t/ha. Nang suit (t/ha) 2 • 0. 8 6. <'. •. •. 1. 4 2 n. n « 10. n . 15. 2006. 2007. Hinh 3. Nang suit 6- nghiem thu'c bon phan diy dii NPK/SSNM. Cac diem va thanh dpc tren do thi bieu dien gia tri trung binh va dp lech chuan, thep thif ty, chp cac gia tn nang suit. 3 2 3. Dap irng nang suit cua cay trong khi bon phan N P va K K i t qua trinh bay a hinh 4 cho t h i y d Tra Vmh c^y ngo cd dap ifng r i t eao khi bdn phan Nang suit (t/ha). N (6-8 t/ha), r i t thip khi bdn phan P va K (< 0,5 t/ha), eho thay ed the giam luang phan P va K f dMng d i gia tang hieu qua k.nh te ma van <5at n3ng suat eao, on dinh NPK SSNM. 10 8 6 4. J. Hinh 4 Dap i>ng nang suat cua cay ngo lai khi bon phan N,P va K Cac diem va thanh dpc tren d6 thi bieu dien gia tn trung binh va dp lech chuan. theo thu ty, cho cac gia tn nang suat 23. 3.2.4. Hieu qua nong hoc cue phan dam, fan va kali. 3.2.5. Lieu luKyng phan NPK khuyen cao cho ngo lai a huyen Cau Ke -Tra Vinh. Hieu qua nong hgc trung binh cue phan dam dat rit cao (30-40kg hat gia tang/kg phan) trong canh tac ngo lai 6" Tra Vinh eho thiy cin bdn nhiiu phan dam d i gia tang nang suit cay trong, trong khi do hieu qua cua phan lan va kali la rat thip (5kg hat gia tang/kg phan P, K bdn). Nhin chung, dya vao kit qua thyc t i ddng rugng ve nang suit muc tieu can dat, nang suit dat dugc khi khong bon phan, dap ifng ciia cay trdng khi bon phan N, P, K, tham khao lygng phan bdn d i nghj trinh bay cc bang 1. 2 & 3, ed thi xay dyng bang hydng dan liiu lugng phan N bdn cho cay ngo lai 6' Tra Vinh nhu trinh bay 6' bang 4: ben canh dd kit hap SLP dung bang so mau la d i diiu chinh luang phan dam ein bdn mgt each phii hgp. Ddi vdi phan P va K do khong cd sy dap ifng ro cua cay trdng, dya theo kit qua thi nghiem ddng rugng va d i nghi d bang 2 & 3, luang phan P va K sCf dung cd thi la 40-50kg P2O5 va 40-50kg K20/ha cho cay ngd lai d huyen Ciu Ke-Tra Vinh. Ngoai ra, tiiy theo sy dap ifng cua phan lan va kali, cd the sif dung bang 2 va 3 d i hudng din bdn phan lan va kali phii hgp 6' cae viing trdng ngo khae a Tra Vinh.. Hieu qua nong hpc ciia phan N (kg hat/kg phan N) 60 50. 40 1 30 i 20 1. • •. 11. i. NPK SSNM. ^. 10. 1 •. 2006. 2007. Hinh 5. Hieu qua nong hpc ciia phan N kg hat/kg phan N d nghiem thyc NPK va SSNM. Cac diem va thanh dpc tren dd thi bieu di§n gia tri trung binh va dp lech chuan, thee thy ty, cho cac gia tri nang suit.. Bang 4. Bang hu'dng dan Ii4u lu-png phan N bon cho cay ngo lai a Tra Vinh Dap yng nang s u i t ddi vdi phan N (tan/ha) -^. Cao. Rat cap. (5- 6 t/ha). (7-8 t/ha). Hieu qua nong hpc (kg nang s u i t gia tang/ kg phan N) ->. Cao. R i t cao. (30-33 kg hat/kgN). (35-40 kg hat/kgN ). kg phan N bon/l t i n nang s u i t gia fang. 30-33 kg N/1 t i n nang s u i t gia tang. 25-29 kg N / l t i n nang s u i t gia tang. Dap yng nang s u i t khi bon dam. (tin/ha) 41 2 3 4 5 6 7 8. Myc phan dam bon (kgN/ha). 150-170 180-200 175-200 200-230. ' c i n sif dung bang so mau la k i t hgp de dieu chinh lugng phan N e i n bdn. 4. KET LUAN VA DE NGH!. Kit qua nghien cifu budc diu d Tra Vinh da cho thiy kha nang ifng dung nguyen ly cua phuang phap quan ly dinh duang theo viing chuyen biet SSNM trong quan ly chit NPK cho. cay ngo lai trong diiu kien dit dai cu t h i d Tr^ Vinh. Viec nghien eifu trien khai phuang phap tren dien rong cin dugc tiep tue thyc hien de cd thi ifng dung rong rai tiin bg ky thuat mdi a nhifng viing trdng ngo lai d Tra Vinh cung nhu d Ddng bing Sdng CCfu Long.. TAI LIEU THAM KHAO Witt C. 2007. Towards an Ecplpgical in Vietnam on Oct 3-5, 2007 at Institute pf Fertilizer & Soil in Hanoi, Vietnam. Intensification of Maize Production in favourable tropical envirpnments. Wprkshpp pn SSNM fpr maize. 24. Summary SITE-SPECIFIC NUTRIENT MANAGEMENT FOR MAIZE IN TRA VINH PROVINCE Nguyen My Hoa Dang Dzuy Minh Phan Thanh Bang Site-specific nutrient management (SSNM) approach for maize has been studied in many maize growing areas in Vietnam. It has been tested on-farm in Tra Vinh in two maize seasons. In 2006, four fertilizer treatments: NPK (200N - 9OP2O5 -100 K2O), PK (9OP2O5- 100 K2O), NK (200N - 100 K2O), and NP (200N - 9OP2O5) were conducted at plant population of 67.000. and in 2007 with one more additional treatment SSNM (200N - 5OP2O5 - 50 K2O) at plant population of 72.000. Results showed that yield at PK treatments was very low (<2 tons/ha), yield at NK (8-9 tons/ha) and NP (7-9 tons/ha) treatments was very high At optimum NPK rate, yields was 7.5-8.5. tons/ha. Yield response to N fertilizer was very high (6-8 tons/ha), while yield response to P and K fertilizer was very low at less than 0.5 tons/ha. Agronpmic efficiency was 30-40kg yield increase per kg N fertilizer, and was 5kg yield increase per kg P and K fertilize applied. Based on guidelines of SSNM approach and results on yield target and yield response found in the study, optimum N fertilizer rates at high and very high yield response to N fertilizer and optimum PK fertilizer rates were suggested. SSNM approach showed promising nutrient management option for recommendation of NPK fertilizer rates for maize in Tra Vinh-Vietnam.. CHI (Pb) TONG SO VA MOI QUAN. HE..,. (Ti ep trang 19). Summary TOTAL Pb CONTENT IN FLUVISOLS OF THE RED RIVER A N D THE CORRELATION WITH SOME PHYSICAL, CHEMICAL PROPERTIES OF SOIL DoTtiu Ha' Pham Quang Ha' Ttie research results on 44 samples soil in 8 provinces in Red river showed that: study soil is acid, total of P and ttie dissolve P are ricti, total OC, N, K^O content and CEC is medium, exchange cations are fair. Heavy metal in study soil is traceable. However, in comparison with 10 TCN 796: 2006 for Fluvisoils soils, some samples soil was polluted. Ttie content of total Lead range from 9,00 to 81,50 mg/kg soil, average content is 42,80mg Pb/kg soil. Comparison with 10 TCN 796: 2006 for Fluvisoils soils, it has. 13,64% of samples were Pb polluted (>60mg Pb/kg). So we need warn about the contamination of Pb in Fluvisols soils of Red river, especial trade villages where are examined for total heavy metals have risk of contamination Pb. Lead content in fluvisols soils of Red river is closely correlated with silky sand, limon, pH and K^G total, K exchange, Ca exchange, CEC and some heavy metal (Cu, Zn. and Cd). Beside, total Pb content correlate weakly with OC, N total, P total and P dissolve, Mg exchange, Na exchange.. 'Soils and Fertilizers Institute. Cac tac gia luu v : Hien nay Tap chi Khoa hoc Dat dang dung kieu chiir VNArial Nar/ow. Mac dii moi font chu tren may vi tinh deu chuyen ddi sang nhau dugc, nhung viec sura chifa van ban sau khi chuyen ddi font chi? Times New Remain sang font chii' VNArial Narrow hien cdn gap nhieu khd khan. Bdi vay d§' sach dupe thdng nhat mdt kidu chi;, d i nghj cac tac gia khdng danh may b^i qifi ehojap ehi Khoa hoc Dat bang kieu chi? Times New Remain, tdt nhat 1^ diing font chur VNArial Narrow 6i tao dieu kien thuan Igi cho khau che bin cua Tap chi. •. 25.