Evaluation of Degradable Spun-Melt 100% Polylactic Acid Nonwoven Mulch Materials in a Greenhouse Environment

The tendency of most commercially available plastic agricultural mulches to undergo only partial fragmentation with time leads to their long-term persistence in soil, resulting in potentially detrimental environmental hazards. Nonwovens composed of biobased polymers such as poly(lactic acid) (PLA) with micron-sized fibers may be potentially valuable for agricultural mulches due to their high mechanical strength and potential ability to undergo complete mineralization. To assess the performance of 100% PLA spunbond (SB) and meltblown (MB) mulches, and commercially available cellulosic mulch, a greenhouse bench study was conducted where the mulches were buried in soil augmented with either lime or compost for 10 and 29 wk to accelerate biodegradation and mineralization. At 10 and 29 wk, MB and SB mulches, respectively, lost considerable mechanical strength for all soil treatments while showing only minimal signs of loss in molecular weight.