An estimated two million tons of plastic mulch films (PMFs) are used in horticultural production worldwide due to the benefits these films provide that may lead to yield increases. Despite the high usage rates of PMFs, there are many environmental drawbacks to the implementation of plastic mulches. To investigate potential mitigation strategies, two plastic and two biodegradable plastic films were used for multiple consecutive growing seasons. Soil conditions, plant yield and mulch durability were used to evaluate the soundness of reusing mulch films for multiple growing seasons. There were no significant differences between mulch types for the first season, with the highest yield being 307.23 pounds of tomatoes and the lowest yield being 235.62 pounds of tomatoes per 50 row feet. There were significant yield differences between mulch types for the second season, where each cabbage head produced on plastic mulches weighed an average of 3.68 pounds while each cabbage head produced on biodegradable mulches weighed between 1.22 and 1.84 pounds. The yield differences observed in season two may be in part due to increased soil penetration resistance under the biodegradable mulches, which had to be replaced at the end of the first season. The biodegradable mulches had to be replaced at the end of the first season due to their extreme degradation, but they were replaced at unfavorably high soil moisture conditions which led to considerable compaction, and higher penetration resistance, in those plots. Biodegradable mulched plots exhibited more than 50% bare ground at the end of the first growing season while plastic mulched plots both exhibited less than 10% bare ground. In addition to their in-field degradation, biodegradable films are also significantly weaker materials than PMFs, with average tensile strengths of 2.02 N and 2.91 N at the end of season one, compared to the average tensile strength of 4.56 N of conventional polyethylene. These results suggest that biodegradable PMFs may not be a good option for use over multiple seasons. Further research is needed to determine the optimum management practices for increased profitability PMFs in vegetable production systems while also improving environmental friendliness.
