MANIPULATION OF INCEPTISOLS POND BOTTOM SOIL THROUGH ADDITION OF ULTISOLS AND VERTISOLS FOR REARING OF RED TILAPIA (Oreochromis sp.) LARVAE
Abstract: The pond bottom soil
of Inceptisols mixed with Ultisols (I-U) and Vertisols (I-G) with the
proportion of (70:30); (50:50); (30:70) showed the improvement of clay fractions
>30% compared with the control (100% Inceptisols). These mixtures were given
basal fertilizer (quail droppings manure with dosage of 2 tons/ha/month), Urea,
and SP36. Cultivation system was divided into two stocked: fish ponds with 50
fish/m2 and ponds without fish. The best mix with the basal fertilizer was
further treated with fertilization treatment (1 ton/ha/month of quail droppings
manure) 3 times within 42 days of larval rearing. Physical and chemical soil
analyses showed an increase of total soil porosity (> 50%), decrease of SG,
BD, and permeability (medium), pH > 5, the CEC > 20 cmol (+) kg-1, and
the C/N ratio < 6.5. The proportion of the best mix of 30% I : 70% U and 50%
I : 50% G with 3 times of the fertilization frequency gave significant improvement
of water quality, chlorophyll-a, diversity of plankton, benthic algae, fish
growth, and total biomass. The presence of mineral montmorillonite on a mixture
of 50% I : 50% G was a very good sign of the bottom soil fertility.
Keywords: ultisols; vertisols;
pond fertility; montmorillonite; soil physical and chemical properties
Author: Saberina Hasibuan,
Bambang Djadmo Kertonegoro, Kamiso Handoyo Nitimulyo, Eko Hanudin
Journal Code: jpperikanangg110011
