Bioassay techniques for soil-nutrient availability

Abstract

In eutrophication control programs, it is necessary to quantify all (algal available) P inputs including those derived from soil and sediment. A one-to-one correspondence between algal availability and the results of chemical analysis does not exist. This research concerned the development of laboratory algal assays for evaluating the availability of soil P as an algal nutrient.Selenastrum capricornutum is an acceptable test organism. Autoclaving soil samples does not result in a consistent, statistically significant change in algal available-P. Maximum algal available-P is achieved with direct contact between soil and algae. Multiple incubation using fresh P-free medium results in significant increases in algal available-P.