Impact of Different Soil Tillage Practices on Microplastic Particle Abundance and Distribution

Microplastic contamination in agricultural soils has become a growing concern due to its potential impact on soil quality and ecosystem health. This study aimed to quantify the abundance, particle shape ratio, and examine the vertical distribution of microplastic particles in agricultural soils under different tillage and fertilization regimes. Field experiments were conducted using a split-split-plot design at two sites with differing land-use histories. Treatments included conventional tillage (ST), conservation tillage (deep (CTD) and shallow (CTS)), and varying fertilization practices. Microplastics (MPs) were detected in 100% of soil samples, ranging from 200 to 7400 particles/kg. Statistical analysis showed significantly lower MPs abundance in CTS compared to CTD, while ST showed intermediate levels. Vertical profiles revealed homogeneous distribution in ST and CTS and heterogeneous distribution in CTD, with the highest accumulation in the topsoil. At the Cacinci site, fertilization significantly increased MPs levels (p = 0.021), supporting the hypothesis that inorganic fertilizers contribute to microplastic input as well. This study highlights the need for agricultural practices that minimize both the input and vertical redistribution of MPs in soils, as well as the need for more research on this topic.