Effects of environmental conditions on the release of phosphorus from biochar

The biochar-water system was adopted as a model to investigate the effect of environmental factors (e.g., P species, retention time, coexisting anions, and nutrient salts) on P release. The results revealed that about 55 wt.% P could be released in 3-4 d, and the P release rate could be controlled by adjusting the environmental factors. The coexisting anions can enhance the P release due to the effect of ion exchange competition. The introduction of Hoagland nutrient solution led to the decrease in the release of P for the formation of precipitates between dissolved P and excessive Ca2+ and Mg2+.