Abstract: A study was conducted to analyze the soil organic carbon and soil nutrient content changes of natural Pinus massoniana forest in the depth of 0-50 cm in north subtropical area of China one year after burning. The results showed that the contents of soil total organic carbon (TOC), easilyoxidized carbon (EOC) and light fraction organic carbon (LFOM) in the burned plots were higher than those in the unburned plots, with respective increases of 4.5%-47.6%, 6.6%-43.0% and 9.0%-49.1% and significant differences in the depths of 0-10 cm and 10-20 cm (P<0.01). Compared with the unburned plots, the soil carbon storage in the depth of 0-50 cm was increased by 23.8% after forest fire. TOC, EOC and LFOM were all significantly correlated to soil nutrients (total N, hydrolysis N, and available K) after forest fire. The main reason for the increased soil organic carbon could be due to the input of organic residues from vegetation layer.

Key words: ibuprofen concentration, population growth, Moina macrocopa, survival, reproduction, algal density.