Predicting the release of mineral nitrogen from hypersaline pond sediments used for brine shrimp Artemia franciscana production in the Mekong Delta

Prediction of soil N availability in highly saline-submerged soils is crucial to optimize the growth of algae and to sustain Artemia production in coastal areas of the Mekong Delta. The results show that there are significant relationships between the amounts of N mineralized in both aerobic and submerged conditions and the fractions of labile soil organic N extractable by hot KCl. The effect of high salinity on N mineralization was tested by submerging soils under saline concentrations of 35, 50, 65, and 80 g NaCl L−1. Increasing salinity resulted in lower mineral N accumulation. However, adverse effects of salinity on N mineralization are short-lived, the rate of N mineralization recovered in later stages. Regardless the inhibition by high salinity of mineral N accumulation, the relationship between the amounts of hot KCl-extractable organic N and available N diffusing from soil into the water column was maintained during the early stages of submergence.