Abstract: Aquic brown soil samples from the Agro-Ecological Experimental Station of Chinese Academy of Sciences in Luancheng of Hebei Province and light chernozem samples from Baicheng of Jilin Province were applied with different doses of phosphorous fertilizer, and aerobically incubated at 25 ℃ for 1, 3, 10, 30, and 60 days. The dynamic changes of Olsen-P and CaCl2-P in the soil samples during incubation were studied, aimed to approach the possibility of agricultural phosphorus non-point source pollution from these soils caused by phosphorous fertilization. In the meantime, Heckrath segmented regression model was used for fitting the Olsen-P and CaCl2-P contents in the two soils after incubated for 60 days to obtain the Olsen-P content corresponding to the environmental sensitive point of soil phosphorus, which would be regarded as the proof of soil phosphorus-fixation capacity. The results indicated that when the phosphorous fertilization rate exceeded 400 kg·hm-2, the Olsen-P and CaCl2-P contents in the two soils increased significantly, and under the same incubation conditions, the quantitative changes of Olsen-P and CaCl2-P in the same phosphorous fertilization treatments were different, illustrating that a phosphorous fertilization rate of > 400 kg·hm-2 increased the possibility of phosphorus loss from the soils, and the phosphorus loss capacity was different between the two soils. After incubated for 60 days, the Olsen-P content corresponding to the environmental sensitive point of soil phosphorus in Luancheng and Baicheng was 889 and 1425 mg·kg-1, respectively, suggesting that the soil from Baicheng had an obviously higher phosphorus fixation capability than that from Luancheng.

Key words: Veterinary additives, Olaquindox, Arsanilic acid, Oxytetracycline, Eisenia foetida, Acute toxicity test, Single cell gel electrophoresis test(SCGE)