Abstract:

Based on the fertilization intensity, environmental safety threshold and fertilization efficiency, a model of environmental risk assessment was adopted to analyze the spatial-temporal features of chemical fertilization in Zhejiang Province from 1978 to 2017. The results showed that the total amount and the intensity of fertilizer used in cultivated land of Zhejiang increased and then decreased from 1978 to 2017, and obvious differences existed in different areas. In 2017, total environmental risk index due to fertilizer use was 0.69, which was at a medium risk level. The environmental risk index of potassium fertilizer application was at low level, and that of nitrogen and phosphate fertilizer application was at medium level. The environmental risk index of fertilizer application in Huzhou and Zhoushan was at a safe level, and that of other regions of Zhejiang Province was at medium level. The nitrogen fertilizer application of 2 cities and potassium fertilizer application of 3 cities were at severe risk level. It is suggested that scientific fertilization technologies should be studied to reduce environmental risks and increase fertilizer use efficiency.

Key words: fertilizer application, safety threshold, fertilization intensity, spatial-temporal distribution, risk index, Zhejiang Province