The current study, which lasted 45 days, was designed
to find a
more effective way to use the vast resources of salt-affected land
and ground saline water for aquaculture. Biochar made from agrowaste
was used as a sediment amendment. The 100 g of biochar was applied
to 25 kg of sediment (i.e., 9.0 ton ha–1) in 300L
capacity fiber reinforced plastic, and Penaeus vannamei
(P. vannamei) (2.74 ± 0.03 g) was stocked at
90 juveniles m–2 in inland ground saline water of
salinity 10 ppt fortified with potassium levels that are 50% equivalent
to those of seawater. Among different treatments, T1 indicates paddy
straw biochar (PSB) application in sediment; T2 indicates sediment
amended with KOH-activated PSB; T3 indicates sugar cane bagasse biochar
(SBB) application in sediment; and T4 indicates sediment amended with
KOH-activated SBB. Compared to the control the potassium (K+), alkalinity, total hardness, calcium/magnesium ratio, and pH of
the water increased significantly (P ≤ 0.05)
in treatments where biochar was used as an amendment in sediment.
The T3 treatment had the best Ca/Mg ratio (1.00:3.12). In water, the
magnitude of increase in K+ concentration from high to
low followed the order: T2 > T4 > T1 > T3 > control. The
concentration
of NH4
+–N in water was found to be increasing
in control, whereas in the rest of the treatments, it decreased significantly
from day 1, until the end of the experiment. Compared to control,
the bulk density was decreased, and sediment cation exchange capacity
and water holding capacity were increased significantly in treatments
where biochar was used as an amendment. The soil microbial parameter
measured in terms of soil enzyme dehydrogenase was significantly different
among treatments at the end of the experiment. Weight gain (%), specific
growth rate (SGR), survival (%), and feed conversion ratio of P. vannamei varied significantly in T1, T2, T3, and
T4 compared to the control. The SGR (2.38b ± 0.05%
day–1) and weight gain (%) in T2, and survival (96.1b ± 2.0%) in T3 treatment were found to be the highest
at the end of the experiment. When biochar was mixed with sediment
in the inland saline system, an improvement was seen in sediment quality,
water quality, and growth characteristics of P. vannamei.