Effects of Microplastics, Fertilization and Pesticides on Alien and Native Plants

Plastic mulches, fertilizers and pesticides have been extensively employed in agriculture to increase crop yields, though it has also led to the inadvertent accumulation of them over time. These accumulations have the potential to disrupt the soil ecological process and subsequently impact the plant community composition. Alien plants always benefit from environmental variability, thus whether the accumulation of fertilizer, plastic, and pesticide in soil promotes the dominance of alien plants in an invaded community. Here, five aliens and co-occurring natives were selected as study materials, and a full factorial experiment was conducted to answer this question. Our study found that microplastics promote the biomass production of native plants at higher nutrient availability while having marginal influence on growth of alien plants. Alien plants exhibited a lower root mass fraction (RMF) with increased nutrient availability and a higher specific leaf area (SLA) in response to the addition of nutrients and microplastics. Pesticide residues in the soil also significantly decreased the root mass fraction of three species, but there was no significant difference between the effects on alien and native species. Overall, our results revealed that alien species adjusted their functional traits more quickly, but native species gained more growth advantages in response to fertilization and microplastics.