5" day - Central Institute of Brackishwater Aquaculture

sodium k4( lhUl 15% md the pH klow 8.5. %line soils uaully tmvc a surf= crua
of wh~w
salt. especially in the dry urson.
1.13 AlWl d l
Thcx soils hvc o h Lm called bluk alkali' soils kuu they ue black.
owing to the cffd of high sodium content which CUIY~ &e diSpcnion ofthe orpanic
Mnar. In &is hp of mil. the wlutim exmctrd 6om a smmted soil anc hu u,
elecmcal condu%vny value mm thn 4 mmWm at 25% &eramount of
exchangeable d ~ u mm m than 15% and the sot1 pH between 8 5 to 10 0
As the bbndtiwater sqwulnnr has expndcd enormously in the -1 arus
whcrc the above m entid soils bvc km observed, the diffmncc between slim
and alkali roils should k well undsmood. Thc wlubk s h which ue mucured and
represented u clcstriul conductivity m ist of utionr md mions. The cations arc
Ca-. Mp", Na'. K' and anions: CQ-, HCOI-. CI', SO,-.
The total uea of soit cdTccted soils in India is about 8 million ha. wt of which
3 1 million ha ue consul line soils including 0.5 million ha of mangrove mas The
details of the extent of saline mils in the difirmt states ue presented in Table I. The
data shows that most of the h c l amas in India ue wlinc in 1983, much before the
devclopmrnt of rlrntilk bncklJlwam fuming pncciees.
Tablc I. Extent of ullne wil la tbc ~ outll states of ladla
State ! Extent of saline soil / Soil salinity
(in ha) (mmhos/cm)
I Wen Bcngal 8.20,448 4-35 :
igr
~uJ~RII 7.14.000 9-20 '
4.00.000 2-50 1
2.76.000 99.950 0 2- 5-17 10 1
86,000 3-10 1
1 Maharnshtra 63.537 4-14
Kersla 26,400 1-20 '
' Goa 18,000 4-15 1
1 A & N tslands 15,000
Pondtcheny 1,000 1-50
Total 2530,335 j
13 Soll qnallly
Before lnltlatlng aquaculture opcnbon. one rhould k well aquatntcd wlth the
nature of soti as a affects the fisNshrtmp productton The propcrt~es of sot1 selected
to aquaculture ue dcscrlbod klow.
1.2.1 soil textarc
Soil texavc refan m the reluin prosa~p of swv& silt and clay in t& roil. It
bu dht bark@ oa the pmdwCivtty of the padr. In krkirhw~a pond* bomhic
productivity is more lmpomnt ha tbc productim of pl.almn. A chycy mil rich in
~cmuta~tbc~ofkaWblved~whichllonpwimthe
associated microorplnim fonn the uuin food of most of the bnckisbwua animals.