Effect of soil temperature increasing by using plastic mulch on germination and seed vigor weeds of Amaranthus retroflexus, Chenopodium album and Avena fatua

Increasing of soil temperature by using plastic mulch is a non-chemical method to control the weed. It has attracted a lot of attention in the last two decades. This study was conducted in the city Fasa in 2018. This study was done as a factorial experiment based on completely randomized design with two factors and three replications. The first factor was the kind of weed, that were Amaranthus retroflexus, Chenoodium album and Avena fatua , the second factor was the time period of plastic mulch, that were 4 levels of control, in which plastic mulch were 15, 30 and 45 days. The results showed that the percentage, germination speed and seed vigor will decrease with higher plastic mulch levels 45 days of plastic mulch caused a reduction of 23.53 percentage in germination speed comparing to the treatment which had control. The percentage, germination speed and seed vigor showed a positive and significant correlation with the activity of Alpha Amylase and a negative and significant correlation with electrical conduction of the seeds. 45 days of plastic mulch increased the period before the 50 percent level of germination and uniformity of germination increased 33.61 and 33.56 respectively comparing to the treatment control. Plastic mulch treatment for 45 days caused a 45.83 percentage decrease in the dry weight of the seedling comparing to the treatment control. On the other hand, a 45 day plastic mulch treatment caused a 33.16 percentage reduction in the activity of Alpha Amylase enzyme comparing to the treatment control. Electrical conduction of seeds showed a negative and significant correlation with the activity of Alpha Amylase enzyme. The result of this study showed that the negative effect of plastic mulch treatment was more on Avena fatua weeds.