K THUT NUI C NC NGT1. Trnh by cc nguyn tc ch yu trong nui c nc ngt? Chn v tr nui. Rt quan trng v quyt nh n kt qu nui v hiu qu kinh t, nht l nui thm canh. Gn ngun cung cp nc, v nc cn c cht lng tt. Nn t tt nht l t tht pha st, khng b nhim phn, nhim mn. Gn ng giao thng b v thy. Xa khu dn c, cng nghip, canh tc nng nghip v d b nhim. Chn ao nui Ngun nc phi c cht lng tt, ch ng. Ao c hnh ch nht l tt nht. t tht/tht pha st l tt nht. che ph i vi ao nui thm canh l 0 v ao nui ghp l 30%. Ao ghp c che ph 2,3 ngy ( trong nui ghp c th phi 1 ngy khng cn phi k bng nui thm canh.) lc nc v cho vo ao. Th c ging. Chn c ging:Sv thc hin: Nguyn Quc Nam Page 7

K THUT NUI C NC NGT Khng sy st, khng mt nht ( chy vo, hng nc). Mu sc c trng, nht l r phi . C ln v ng u. Mt th: Qung canh: 1-2con/m2. Qung canh ci tin: 2-3 con/m2. Bn thm canh: 4-5 con/m2. Chn i tng nui v t l ghp: Da vo: Hai nguyn tc ca nui ghp: o Chn c sng cc tng nc. o Khng chn loi c c cng tp tnh n. Kh nng cung cp phn bn, thc n. Kh nng ng vn. Vng a l. Mc ch ngi nui. T ngi ta a ra cc cng thc ghp cc i tng nui vi t l a dng khc nhau. Thi im v cch th c: Thi im th c: lc nc mt ( nhit thp, sng). Cch th c: ngm bao c vo trong ao khong 10-15 ph ri th t t ra gai cha, tm c bng mui n ( 5-10ppt) th c tm trc tip ra ao. Bn phn v cho n. Phn bn: liu lng v tn sut bn phn. Phn heo: 15-25kg/100m2/5-7 ngy. Phn xanh: 20-30kg/100m2/5-7 ngy. Urea: 0,1- 0,2 kg/100m2. NPK /DAP: 0,5- 0,6kg/ 100m2. Liu lng thay i theo mu nc ( mu nc dao ng trong khong xanh t chui n mu xanh v u xanh l tt). Thc n: Nui QC, QCCT: tn dng thc n sn c. Nui BTC: thc n t ch l chnh. Khu phn n : 2-3% trng lng c.Sv thc hin: Nguyn Quc Nam Page 8

K THUT NUI C NC NGTChm sc. ch hi ( quan trng lc mi th c). Cht lng nc ao : nh gi cht lng bng cm quan l chnh. Theo di mu sc nc ao iu chnh lng phn bn. Quan st hin tng ni u ca c, nh gi xem l hin tng bnh l hay sinh l. Theo di hot ng ca c. Thu hoch. Khi c t kch c theo yu cu th thu hoch. C th thu ta hoc thu ton b . 11. Nhng tiu chun chung chon mua c ging th nui? Trong , tiu chun no l quan trng nht, ti sao? Tiu chun chn c ging. C khng sy st, mt nht (chy vo, hng nc). C chy vo, hng nc, p bng cng nhiu th c cng khe mnh. Mu sc c trng. C iu hng c t l chm en phi di 5%. C tra: lng xanh en, bng mu trng bc, cc sc dc theo thn phi r rng. C ln v ng u. C c ngun gc r rng. Tiu chun quan trng nht: c c ngun gc r rng. V: Do nhu cu li nhun, nng dn thng mua c ging tri ni vi gi r hn 30% so vi gi c ging ca cc tri sn xut ging c uy tn. Nhng nu so snh t l hao ht, c tri ni hao ht hn 50% s lng th nui, cn cht lng con ging t tri sn xut ging ch hao ht 20%. Nn hiu qu sn xut cng t l thun vi s tin u t. Bit c nhng c im b m ca con ging . Ging tri ni thng s dng c b m qu tui khai thc hoc cha n tui khai thc cho sinh sn tui cha cht v sc lm nh hng n sc khe ca n c con. Dng thuc kch dc t kch thch sinh sn qu liu, lm cho con c bt yu i.Mc khc, ti u li nhun, hin tng th c b m chung n din ra thng xuyn, khng c qun l. Do , dn nSv thc hin: Nguyn Quc Nam Page 9

K THUT NUI C NC NGTcon c thng phm yu i v cn huyt, cc gen ln biu hin xu gp nhau bc l ra ngoi, sc khng khng cao nn d d mn cm vi mi trng, nhim dch bnh, t l hao ht cao, hiu qu nui thp. 12. Nhng u v nhc im trong m hnh nui c rung la? u im. Tn dng thc n t nhin, hn ch c di v cn trng gy hi, nng sut la tng. Gim lng thuc tr su, mi trng nui sch hn, sc khe nng dn ci thin. Kt hp a dng sinh hc trong h thng canh tc gip m hnh mang tnh bn vng cao v a dng sinh hc. Nng cao thu nhp ngi dn. Ci thin ngun m ng vt cho nng h. To vic lm cho ngi dn trong vng. u t nhiu vo m hnh gip nng dn c tng sng to hn. Yu cu hp tc gia cc nng h trong m hnh nui c rung gip pht trin cng ng nng thn. Hn ch. u t nhiu cng sc trong qun l v chm sc. Yu cu k thut cao, cn c nhiu kinh nghim ,i hi phi c cc hot ng khuyn ng thch hp. C c th b cht hng lot nu phi s dng thuc tr su cho rung. Khi mt la qu dy, c khng th ly thc n v chm ln. Vic s dng cc ging la cao sn nng cao nng sut ngy cng thu hp kh nng nui c trong rung la. Do: Cc ging la cao sn thng i hi ch phn bn v thuc tr su kh cht ch, c bit thuc tr su l yu t khng th thiu nhng li khng th s dng nhiu khi nui c. Chu k canh tc ngn lm cho thi gian nui c ngn. Cc ging la cao sn yu cu mc nc rt thp nn kh c ln rung. C thng nui c gi tr kinh t thp. Nng sut khng n nh v kh d on.Sv thc hin: Nguyn Quc Nam Page 10

K THUT NUI C NC NGT13. Trnh by s tc ng qua li gia la v c trong m hnh nui c rung la? La i vi c. Mc nc thp lm cho nhit nc thay i nhiu trong ngy nh hng n tng trng ca c. Trng la qu dy lm cn tr s bi li v kim mi ca c, lm nng sut khng t mc ti a. Rung la cung cp thc n v l ni tr n ca c. Hm lng thuc tr su cao nh hng n tng trng ca c v c th tch ly gy nh hng n ngi. C i vi la. Din tch trng la gim, nhng tng thu nhp nng h c th c ci thin nh thu nhp thm t c. C c kh nng lm ti xp t, gip r la h hp v pht trin tt, nng sut la cao hn (10-15%). t tn cng lm t. Mt s loi c n thc vt gip dit c di, lm gim cng lm c. Phn c l ngun phn hu c b sung li cho rung la, gip tng nng sut. Gim chi ph s dng thuc tr su, nng cao li nhun. 14. Trnh by cc nguyn tc chn loi c nui trong rung la? Nhng loi c no thng c nui trong rung la? Nguyn tc. C c kh nng chu ng s thay i ca mi trng cao: thay i nhit , oxy thp, c cao, mc nc cn Sc tng trng nhanh, t c kch thc thng phm trong thi gian cho php. C tnh n tp tn dng thc n t nhin trong rung la, nht l cc loi c n cn trng, mn b hu c v to. Khng s dng c n thc vt v c c th n la. Cc loi c thng c nui. Cc loi c: r phi, chp, sc rn, m vinh. T l th ghp gia cch loi ny thng l: 35-40% m vinh, 10-15% r phi, 15-20% chp v 10% c khc.Sv thc hin: Nguyn Quc Nam Page 11

K THUT NUI C NC NGT C m vinh l loi c quan trng trong nui c rung v n thch hp nht vi cc loi thc n trong rung la. 15. Trnh by tm tt qui trnh k thut nui thm canh c tra trong ao t? Trong , cng on k thut no quan trng nht, quyt nh n cht lng tht? Chun b ao. Chn ao nui. Din tch >= 5000m2, su 2,5 3,5m. Ngun nc sch v ch ng, ph = 6,5 8. B ao cng cp thot nc kin c. Quang ng, khng cy ci che ph. Gn ng giao thng thy, b. Chun b ao. Dn ao, v sinh ao: sau mi v nui cn sn vt y ao tht k, ht b bn y ao, li lp bn to n hoa trong ao v cc c t pht sinh t qu trnh phn hy cc cht thi trong ao nui lm cc i tng nui d b nhim bnh, thiu Oxy hay nhim c tnh ca cc cht chuyn ho. Cht lng c tra ging: Cht lng c ging ngy cng suy gim nh hng ln n nng sut v thi v nui. t c kch c c thng phm (khong 1- 1,1 kg/con) ngi nui phi b ra 7- 8 thng. Trc y, ch cn 5- 6 thng. Nguyn nhn quan trng lm tng chi ph sx c tra hin nay. Thc n nhn to: Th trng thc n chn nui ang ph thuc vo nc ngoi do 70% nguyn liu nh bt c, b u nnh, premix, phi nhp khu trong khi nc ta l mt nc xut khu nng nghip. Thc n chn nui lin tc tng nn gi thnh sn xut c b y ln cao, t tng ri ro cho ngi nui. Qun l: Ngnh nng nghip cha c bin php hiu qu qun l cht ch v iu kin nui c tra thm canh, dn n s pht trin t pht, ngoi quy hoch lm gi c khng n nh, tnh trng tha thiu nguyn liu thng xuyn xy ra. Cha c bin php pht trin sn phm y trin vng ny mt cch bn vng, nn ri ro m ngi nui c v DN vn cn mc cao. i vo sn xut hng ha th phi n nh v cht lng, cnh tranh cng bng trong mua bn v m bo an ton thc phm theo quy nh ca cc nc nhp khu. Nhn thc, trnh hiu bit, qun l v tiu chun cht lng sn phm cn nhiu hn ch, trong khi cc h thng qun l cht lng a dng, thay i ty thuc vo tng khch hng, mi th trng li c nhng tiu chun rt khc nhau. Thun li. iu kin t nhin:

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K THUT NUI C NC NGT Cht lng v dng chy ca sng Tin v sng Hu (sng Cu Long - BSCL) thch hp cho vic nui c b. Ngun thc n t nhin: Ngun nguyn liu lm thc n cho c rt phong ph. iu kin giao thng thy v b thun tin cng gip cho vic vn chuyn nguyn vt liu ch bin thc n cho c c d dng v kp thi. Kinh nghim nui b c tch ly qua nhiu nm ca nhn dn a phng. C tra v c basa cng c c th trng xut khu vi nhu cu s lng ln. 17. Trnh by nguyn tc dng chn v tr neo u b nui c trn sng? Dc hai b sng hoc b h: thun tin cho vic xy dng tri nui. Ni c dng chy lin tc, thng thong, lu tc thch hp (0,2 0,5m/s). Mc nc sng t thay i theo thy triu v su ti thiu phi cao hn chiu cao ngp nc ca b 0,5 - 1m trnh cho b khng b i ln mt nc. Nc sng khng nh hng trc tip nc phn, trong ma kh khi nc b nhim mn th mn cho php c chu ng c v khng thay i t ngt. Trnh ni c lung nc ngm, ni khc quanh ca sng, ni sng bi t, xi l, ni c nhiu rong c, ni dng nc c qu nhiu ph sa. Ni yn tnh, t tu b qua li trnh gy stress cho c, va trnh nhim Ngun nc lu thng tng i trong sch, khng b nhim. Xa khu vc thi cht khi sinh hot, cng nghip. Gn ngun cung cp thc phm nui c, v tr thun tin giao lu, gn cc trc l giao thng thy b vic vn chuyn thc n, c ging v bun bn c tht c d dng thun li. 18. Nhng yu t nh hng n s sng ca c ging khi vn chuyn? Nhit .Sv thc hin: Nguyn Quc Nam Page 15

K THUT NUI C NC NGT Nhit nh hng n: Kh nng ha tan oxy vo nc. Cng h hp. Qu trnh trao i cht. Cng h hp. Mt c khi vn chuyn. Kh carbonic v pH. nh hng n: CO2 c to ra do qu trnh h hp ca c. Trong nc, CO2 nhiu dng nh: CO2, H2CO3, HCO3-. Khi nng H+ cao th pH nc gim v s nh hng n cc hot ng sinh l bn trong c th nh: o Cn tr s trao i oxy ca hng cu. o Lm tng ngng oxy ca c. C thnh thc c ngng O2 cao hn. o Kh thi CO2 ra khi c th c. tiu hao oxy. nh hng n: Qu trnh TC quyt nh n tiu hao O2. tiu hao oxy ph thuc vo: o C c, loi c. C c cqhhp c tiu hao O2 < c khng c cqhhp. C nh c tiu hao O2 > c ln. o Nhit nc. Nhit nc cng cao th O2 cng ln. Kh NH3 NH3 c to ra t s phn hy vt cht hu c do VSV di iu kin him kh v trong nc kh NH3 thng tn ti di dng NH4OH (NH4+). Khi pH tng th lng NH3 tng, H2S gim. Ph thuc vo: no i ca c. Cht lng nc. o Nc c nhiu cht hu c s c nhiu NH3 hn.Sv thc hin: Nguyn Quc Nam Page 16

K THUT NUI C NC NGT Nhit nc. o Nhit nc cao => nhiu NH3. Mt vi sinh vt k kh. o t vsv => t sinh NH3. S sy st v mt nht. S sy st xy ra do ko li. Khng ng k thut, ko li lc c n no. S mt nht xy ra khi ko li lc nhit nc cao. nh hng ca mt nht: c trng ui (c ging), c tut nht (c ln) => lm c cht. 19. Th no l vn chuyn h v vn chuyn kn? Cho v d minh ha? Vn chuyn h: L phng php vn chuyn c sc kh tng hm lng O2 trong sut qung ng vn chuyn. Hoc khng sc kh m tng O2 trong dng c vn chuyn bng cch tng din tch mt thong. Vn chuyn kn: C bm O2 vo trong dng c vn chuyn khi ng gi v c s s dng lng O2 ny trong sut qu trnh vn chuyn. Vn chuyn kn. Nc VC. Thng p dng cho cc loi c. Dng c VC. Phng tin VC. H thng sc kh. Nguyn tc VC c b m. c lp vi mi trng bn ngoi. Vn chuyn h.

tip xc vi khng kh or trao i vi mi trng nc bn ngoi. trng, c bt, c ging, c khng c tra ging, c tra tht, c c CQHHP, c c vy mm (c CQHHP, vy cng, sc nhn (c tht). tht). bao nylon, oxy thau, thng sn, thng,b xe, my bay, tu thuyn. xe, thuyn thng thy. VC ng b. C i, khe mnh, khng sy C i, khe mnh, khng sy st. st. Nc VC trong v sch. Nc VC trong v sch. H thng sc kh hot ng tt.Page 17

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K THUT NUI C NC NGTMt vn chuyn. Trong 5h. Ph thuc:loi c, c c, nhit , thi gian vn chuyn. 12-15kg/bao 60-100cm . c c CQHHP: 250-350kg/m3 C khng c CQHHP: 100150kg/m3.

20. S bin ng hm lng DO trong ao nui c trong mt ngy m? Gia ao bn phn v khng bn phn, s bin ng ny din ra nh th no? S bin ng DO. Nng Oxy ha tan trong nc bnh thng cao trong nhng ngy nng, t mc ti a vo cui bui chiu(13-15 gi), gim dn v ban m, t mc thp nht vo lc bnh minh(4-6 gi). Lng oxy trong nc thay i lin tc. Vo ban ngy, lng oxy trong nc cao do c nh sng gip to quang hp v to ra nhiu oxy trong nc. Ban m khng c nh sng to khng quang hp c nn khng to ra oxy. Hn na, ban m to phi th nhiu nn lng oxy gim thp nht l sng sm. Oxy cn bin ng ln theo su ca ao, tng mt hm lng oxy cao hn tng y. Nhng ngy tri m u, ma bo ko di th oxy thng b gim thp. Gia ao bn v khng bn phn, s bin ng ny din ra. Ao bn phn. Vic bn phn nhm mc ch kch thch to pht trin, lm thc n s cp cho ng vt thy sn. To quang hp thi oxygen vo ban ngy v h hp hp thu oxygen vo ban m lm cho s bin ng DO r rt. C th: hm lng DO cao vo ban ngy v gim dn vo ban m. Ao khng bn phn. Trong nui thm canh, ao khng bn phn (tr c sc rn). Do , mt to thp, hm lng DO ch ph thuc vo s khuych tn oxygen t mi trng khng kh vo nc. S bin ng ca hm lng DO gia ngy v m khng r rt nh ao bn phn.

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