Degradation of Biodegradable Plastic Mulch Film and Its Effect on the Yield of Cotton in Xinjiang Region,China

Soil pollution caused by residual plastic mulch film in field has been a serious problem in Xinjiang region.Biodegrable plastic mulch film has assumed a final way to solve this problem.Field experiment was conducted in Shihezi city of Xinjiang region with three kind of biodegradable mulch film(A,B,C) provided by Guangdong Shangjiu Biodegradable plastic Co.,LTD in 2009.Traditioal non-degradable clear plastic mulch film(CK1) and biodegradable plastic mulch film made in Japan(CK2) were treated as control treatments.The results showed that different biodegradable mulch film had a different degradable performance.Impacts of different plastic mulch film on soil temperature,soil moisture and cotton yield were also different.Comparing to the CK2,The degradation process of test biodegradable mulch film was more faster than that of biodegradable mulch film made in Japan whether covered on soil surface or buried in the soil.The degradation process of test A and B was faster than tested C.The earlier degradation of tested biodgradable mulch film A and B led to the significant effects on its function.Comparing with the CK1 treatment,the soil temperature covered by test biodegradable mulch film A and B was lower to 2~3 ℃,water storing capacity decreased 3%~5% and cotton yield reduced more than 20%.Test C and CK2 were better than A and B.The cotton yield had no significant differeces with CK1.