Water quality management has been considered one of the most important factors in aquaculture techniques, but less pay attention in pond bottom soil quality management (Boyd 2002). Poor sediment conditions may cause low survival and poor production of shrimp aquaculture. It is therefore important to investigate physicochemical characteristics of aquaculture pond sediments. Sediment samples were taken randomly from five semi-intensive aquaculture ponds in the Tam Giang Lagoon in Sep. 2010 (dry season) and March 2011 (wet season) by using a 5–cm diameter core sampler, which was designed to trap a layer of soil 0–2 cm, 2–6 cm and 6–10 cm depth from the pond bottom interface. The results indicated that there was a significant difference between sediment layers for nutrient elements: total carbon (TC); total nitrogen (TN), C: N ratio, total phosphorus (TP), mineral composition (p<0.05). But there was not found significant difference in δ15N between sediment layers and shrimp culture cycle seasons (p>0.05).
Keywords: Aquaculture, mineral composition, nutrient elements, physico-chemical, soil layer.