145 lines
5.8 KiB
Plaintext
145 lines
5.8 KiB
Plaintext
asirorllrlvr losselrl (ism, Cyranrlos earpre llsm and
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honors gonlnnolrs (35m yve besl ylelds, Allznlalively,
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slrrnillrrudrrl rrlossrrnlrreus (50%), Heloslamr nil-7.»,
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arreoeinlvs llsael, Fuulmx um, and Cyrrlrlrs rrrprr
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”11%? Ire sallslarlory, mle pereenlages are nurse oi iry
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or llngerllngs oi lbese speensl sllell pclymhnms are
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rile resull rl a series oi lrials ln padl, and all use
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wudqalingspec and predalorsloeenbol srnall urn
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Crayllsn lcmbrrlls elurlllrl are also sroelred in rire pa ,
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a dilllcull and speoalrsed pond syslrnl, bul llnel ll
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yleldsrllere nlay adda erirleal elelnenr Io nnmllml
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We generally elasslly warers land in parlieular
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sewage lagoorlsl as
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. AERDBIC' when oxygen ls well—supplled by wlm
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avznum. eurbulenl now, aeralors, or rapids, and where
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mere is r liglll load ul delaylng organlelnalerial.
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- rllcuumve: lrnany swalnps and weed-elugged
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ponds, seeondary lmalmzm sewage ponds) wilere llle
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suriare may be armed, bul wilene sedlnlenr or sludge
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eollecls in rold periods and llle pond base becomes
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anaeroblr lsulpnurearlng baelerin alerl demupwe ille
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sedirnenlsl,
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e ANAERDBXC‘ pl-inlary sewage ponds and overe
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rerllllsed shallows wbero rilere is a low (I ppm or less)
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oxygen srarus
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As less oxygen ean be ssolved in warrn waler lban
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lo oold waler, and as line planrs lbar produee oxygen by
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day consume ll oi nlglu. (hue ls a danger lnal hunky,
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weedenlled shalluw ponds may develop severe oxygen
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delie ney on warrn summer nlgllls ll valuable llsll
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§|D(ki are lneld lbere, rare should be lalren lo bolll
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reduee rne level oi wasles ln llle pond. and lo arrange
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ler aulorrlarle aerallun al rrrlieally low levels» Such
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dangers are less ln elearwaler, told, and open or
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nowrng pond syslenls whelv lllls laelor earl sunlenrnes
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be lgnored However, oxygen supply berornes a
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llrnlllng iaelor m llsll sloer densiry or levels above soon
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kg/ha or lbereabouls. and linen oxygen as an bubbles
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needs lo be supplied lbigore 13.7),
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nlere are several eornrnelrral aeralors on llne rnarkel,
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and many ran be solakpuwfld. mrr wnerever waler
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ean be led lrorn a ilead ol 1 in ur nlure, lonnlains,
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sllowers. and ‘Fluwtnmls“ lrigure ml WIII orygenale
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ponds. A considerable energy savlng I5 aellleved ll only
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pan oi me pond ls aelaled ar trilkdl peoods, hsh wrll
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gather llselrlel llneru ln lloles oi need For eels. rnis
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aeraled seenon is bulll wirn a narrow pass lo IN rnaln
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pond lo prevenr aeraled walereseaplng
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ll ls ollen ldeal lo eonrblne rile leeding srabon wirn
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rile uxygenikd area so llnar rood wasles are also
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oxidised and wasle eonlrol slnlplllled, some suen
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arrangenlerll is llluslraled ln rlgure 13.3
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AClDrflvALKALINlTY
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Funds in areas oi pears, mangroves, eordgrass liars,
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sarnplllres, and mm Malt: derlved lruln lleallns and
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granules, or sllleeous soils, an be very and in reaellon
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lpl-l w 0:155), lhe ands being llunue aelds, rannlns,
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and nllnor organle aelds. in sueil eases. nydrogen
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sulplllde may also be released by ponded peels or
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swarnpr lo ereare sulpnurie and real slrlpplng,
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rnounding, besil—waler or raln leaelllng, and llrrung are
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all ulcd lo bring and. ponds lnro produerlon. Below lne
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penis, and espeelally in basalllr soils, blulsll elays
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produeed under reduelng condlllens ulay oeeur (ans
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aerobie or low prll. Fish wlll rilrlve ln oulle re
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lnnrurall walers ll ealelunl rsavailable
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I! we drain pears, me organle rnnrerial drles onl.
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uxldlsh, and relearrs errbon diqxide, gradually loslng
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bullr so am some fields ln lens slnwly Sink below dram
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or even sea level Fens arederlved irool nllralrne walers,
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bogs and peals ilorn andle warers Marshes, lens, and
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bogs eonlaul uninue planl speeles and are rien wrldlrre
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lnabrlalsi bopelully, lne era 0! ien drainage ls dmwmg lo
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a close, as rile preservallon oi welland nabllal ls a
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prlorrly or all enligblened governrnonls and
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Iandawnm
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As pond pl-l ls ideally 6H1) or even lo 5.5, and only
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a low llsn gmw well below lllese levels lnolably
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salrnonids, wruch are also one 0! rlle lew saosloelory
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fish irl mwlllum). rnosl eullureponds are roulinely
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llrned wllen llley are made. mey ere also regularly
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clleeked lor pH levels, wilial areadlusled willl unburnl
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llnle alrer rile irlioal bul-nr llnle dressing. Thus, in rive
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rnaner oi sire selemon, ll ls ol greal advanrage lo sue
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ponds where runalll lrorn llrnesrone areas can be
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ponded, or wilere mluul pH levels are already rugn
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Lerllal lirnlls ior rnosr llsll are pH 3 7 laeldl and “1.5
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lallorllnrl
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in pracllse, we ean alrn lora pH rnosaie in ponds and
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pond senes, as enany valuable lood organlslns preler
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soil laeidl waler, wlliln llsrl, rnolluses, and l-resnwaler
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lobslers rnd prawns preler bard lallrallnel walers
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Crushed dolonllle, nlorble enlps, nurd llnleslone
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gravels, and oysler or rnursel shells glue a slow release
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0! ralourn in unlls small ponds, lnlalle llller syslenls.
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and me upper sedlons or eanal syslenls,
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Thzrv is an lnleraellon wrrn pH, resplrarlorl, and
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plan denslry; pH may rise al niglll or in dogged edasral
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walers wi|h clear. and nth! algal lonns, or tall as pears
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form-Ml anaerobieron - onsdrveloo
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Nol all organlsrns appreeirle bard waler lsalrlurrl
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mill, and ll aeeessory ponds ore lo be developed [0
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breed soil—waler llsh, lorages, or rnaln erop, only
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organlr arms :Iv used, smelly ilydroenlorie, bonus, or
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pllospnorls acids. The sarne ellecl earl be somerirnrs
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pmdueed by using a pal or dense [IN/pea? are. ln
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llller warer. by laylng peals on line pond base, and by
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eleallng . swarnpy eondroon around lbe eullure pond
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MUD. 5m, rluMUs, AND WASTE REMOVAL
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Wasles oi any nalune in ponds reduce waler quallly ll
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llley oodlr ln exeess, or ll they oeeur as dead rnaredrl.
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We n in sorne wlys dislingulsil mung wasles hum
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lerrl lsers, as me laller need nol ereare erosslve gromll
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ll hubivomus rlslo nuoia la laege lquan: modem), or
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shrimp are ave lable lo eal lbe den-nus or weeds lllar
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would orberwrse die and oroarr arueroble eorvdruons
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465
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