GROWTH RESPONSE OF PHYTOPLANKTON TO DIFFERENT SOIL EXTRACTS FOR CHOOSING SUITABLE SOIL TYPES FOR POND AQUACULTURE

For choosing suitable soil types for aquaculture pond construction, the density, biomass, and dominant species of phytoplankton were used as dependent variables to test the effect of acid yellow soil, neutral purple soil, and alkaline purple soil of Sichuan Basin, China. The results showed that the acid yellow soil extracts had a low nutrient content and low primary productivity. The neutral purple soil extracts had a low content of major elements, but a high content of microelements. The alkaline purple soil extracts had relatively high nutrient contents and promoted the growth of phytoplankton which enhanced the grazing of zooplankton and planktivorous fish. These results indicate that the alkaline purple soil is better for aquaculture pond construction than the acid yellow soil and neutral purple soil. This work provides an evaluation method for selecting pond bases for aquaculture, and will benefit further research to explore the fishery suitability of soils and developing aquaculture according to the local soil conditions.