A beel thicky infested with water hyacinth
A beel thicky infested with water hyacinth
A beel thicky infested with water hyacinth
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Available soil nitrogen squs represents the easily oxidisahle form of total<br />
nitrogen in the soil and its level is influend largely by the organic matter content of<br />
the soil. Available nitrogen followed the trend of organic carbon and its values ranged<br />
from 145 to 410 mg/l. It was ratha low in the bxls of both the Brahmaputra valley and<br />
the Barak valley from a fisheries point of view The low available nibogen of soils is<br />
mainly due to reduced microbial activities rn d slow rate of decomposition of soil<br />
organic matter on account of the prevailing atidic reaction of the soil. Beels of the<br />
Brahmaputra valley had higher mean value of a\ ailable nitrogen compared to the Barak<br />
valley. Beels of Central Assarn showed high. st mean value of available nitrogen.<br />
followed by Lower and Upper Assam.<br />
Ava~lable soil phosphorus, important in nfluencing the aquatlc product~\,ity.<br />
\*.as rather poor in most of the heels and the valu: -an@ between 0.8 and 27.0 mg kg:l<br />
Such lo& level of available so11 phosphoru is attributable to the prcscnrc of<br />
macrophytes, especially the rooted ones wh~ch ,pidly use up most of the ava~lahle<br />
phosphorus. Becls of the Brahmaputra valley ha h~gher level of available phosphorus<br />
(14.5 mg ;kg) compared to the Barak valley (8.: rng/kg). Beels of Central Assam had<br />
the highest mean value of ava~lable-P followed I y Lower and Upper Assam Calc~um<br />
carbonate content ranged from 4.5 to 67.0 gkg u !h the mean value of 23.0 gkg. Hcels<br />
of Barak \alley had sl~ghtly h~gher mean value I f CaCO, than <strong>beel</strong>s of Rrahnlaputra<br />
valley uhilc same mean value was recorded in 111. beck of Lower. Central and llppcr<br />
Assani.<br />
Loamy soil contain~ng all the three fracl,.lns almost in equal proponions IS<br />
cons~dered to be conduccve to product~vity. Houever, most of the <strong>beel</strong>s studled by<br />
CIFRl had poor soil texture. Beels of Karimgwj t,~strict of Barak valley and Sihsagar<br />
d~str~ct of Upper Assarn had better soil texture coml ared to other districts. It 1s ohserved<br />
that thc soil of the heels of Brahmaputra valley arc more productive than that of Barak<br />
valley <strong>beel</strong>s. Among the distncts of Brahmaputra isalley, <strong>beel</strong>s of Central Assani arc<br />
more conduc~ve to biological productiv~ty In resp .ct of organlc carbon and nutnent<br />
status of the so~l. Soil qual~ty in <strong>beel</strong>s of d~ffere~: regions of Assam is depicted In<br />
Table 7.