5" day - Central Institute of Brackishwater Aquaculture

and tot81 8Iluli11ii rmly hid be of rmu~a in krlrbmw p d . Mmy tima
thenedforlimeirfvsrru~whcairorgfo*faril~frikecproduce~
adequate plrnkMI baom. In brackishwater soils, whac wxtu cxchngc is no^ used
and mils m ridic a mm whem *lacr achtrye is uad kn whac roils arc
cxbrmcly acidic (rid-sulfkte roils). liming may sraan mar importance.
Wiry walmatba of Ulr utcrh*
The canmucblly waikbk lime macri.b have to be colkctcd and ~aiyscd far
their newlliPtion value. The term "namrliing vduc" refers to the mlative ability of
lime MtnLls to neutnlir widity. Rm cakiwn urbonuc is assigned a
neuhalirstion vdue (NV) of 100 per mu aad is the aud.rd against which various
lime m8tsri.l~ M corn@. The neuh.lisb porn is nothing but a su(emcnt of its
strength with ref- ec cakium cdrbma a its cakium urbant. equivaknt
(CCE). The l i mudrl, .mn dsvod 60 umh she (035 mm) md
mlyd fa their CCE whea. Ths A m tho llme muai.l, quicke~ is the mction
wlth the aoii. Diffmt lime maairts rvaihbk in the mukn vuy casidanbly in
their puticie size. A mechanical analysis is made by the use of different mesh sieves
to calculate the fineness factor or eff~iency rating (ER).
The ulcuhtion of finmu fanor rating fa r sampk of ngricul~rnl lime none
that w8a ~ b j lo d sieve uulysis is as follows. Thc pmicla of lime passing
through 60 mesh rim ur nmd I W per om atlc*n& the puring through the 8
mesh skw us W 5 O par om &imt and those ratlined on 8 mesh sieve M rated
20 percent eff~inn. Finally, the per cmt efkaivc cakium clrborratc (PECC) value
was h i n d by multiplying the estimated CCE with fineness factor values.
Calcnhtion of llme rqmlrwmemt lor pods:
Thc lime rquirrment of r roil un be defined as the mount of lime material
thal murc k ddcd to rai~ the soil pH to 7.0. FinL the mount of lime needed as
pure cdcium urbonuc is uloul8wd bud on tho raw1 pH of pond mil and LC
nrmnt of the ug to be applld. Vdwr of llming nm u purr C.C% (mnJkr) with
M eftlcieney of 100 psmant am calculated from the fwmulae given below.
Desired pH - Actual pH
-- X 0.5
0.1
Lime needed - -- Xam
EfAcioncy of lime
Then. the recommended dose for vaious lime materials was calculated by
dividing the value of lime needed as pure C.CO, wlch the PECC value of that
particular lime MJerilrl with dtc f muk giva below.
Recommended rate of application of lime merial (tonslba) :
Liming nte as pure CAC~ (to&)
mc1 -
1'("?1
what. PECC - Psnsnt eRsctive alc~um urbarm a cfliciency prcan