Abstract: The effects of photosensitizers on the mechanical properties of polyethylene mulching films were studied systematically under real field conditions by single and orthogonal factor experiments. The experimental results indicated that the ferric stcarate played a major role in accelerating the photodegra-
elation of polyethylene. Ferrocene was less sensitive than ferric stcarate. When used alone, nickelN，N-dibuty dithiocarbamate could retard the aging of polyethylene, while used with ferric stcarate could prolong the induction period and accelerate the degradation of mulching films later. However, when it was used with ferrocene, the degradation period was longer than that used with ferric stcarate.

Key words: polyethylene, mulching film, environmental degradation, photosensitizer, mechanical property