|dc.description.abstract||Bottom soil samples were collected from 42 catfish (Clarias hybrid) ponds, 40 freshwater prawn (Macrobrachium rosenbergii) ponds, and 18 carp (Puntius spp.) ponds in Thailand. The ponds ranged from 1 to 30 years in age. Regression analysis revealed that pond age was not a major factor influencing the physical and chemical composition of pond soils. Sediment depth, S horizon thickness, and bulk density of S horizon were greater for carp ponds than for catfish and prawn ponds. This resulted because sediment was removed from catfish and prawn ponds more frequently than from carp ponds. Total carbon, organic carbon, and total nitrogen concentrations were higher in carp ponds than
prawn and catfish ponds. However, few ponds had sediment organic carbon concentrations above 3%, and carbon:nitrogen ratios did not differ among the three cultured species.
Total phosphorus and other soil phosphorus fractions increased in the order prawn ponds, carp ponds, and catfish ponds. Soil sulfur concentrations also increased in the same order. There were no differences in major or minor nutrients in bottom soils that would influence aquacultural production. Although there were significant correlations between various soil quality variables, no single variable or group of a few variables would be useful in estimating soil quality.
Best management practices recommended for improving pond bottom quality were drying of bottom between crops, liming, tilling, and periodic sediment removal. Best management practices for preventing high total suspended solids concentrations in pond effluents also were recommended.||en_US