Plastic contamination of terrestrial ecosystems and arable soils pose potentially negative impacts on
several soil functions. Whereas substantial plastic contamination is now traceable in agro-landscapes,
often internal-caused by the application of fertilizers such as sewage sludge, questions remain
unanswered concerning what happens to the plastic after incorporation. Based on a combined surface
and depth sampling approach, including density separation, fuorescence staining and ATR-FTIR or
µFTIR analyses, we quantifed macro- and microplastic abundance on two agricultural felds—34 years
after the last sewage sludge application. By sub-dividing the study area around sludge application
sites, we were able to determine spatial distribution and spreading of plastics. Past sewage sludge
application led to a still high density of macroplastics (637.12 items per hectare) on agricultural soil
surfaces. Microplastic concentration, measured down to 90 cm depth, ranged from 0.00 to 56.18
particles per kg of dry soil weight. Maximum microplastic concentrations were found in regularly
ploughed topsoils. After 34 years without sewage sludge application, macro- and microplastic loads
were signifcantly higher on former application areas, compared to surrounding areas without history
of direct sewage application. We found that anthropogenic ploughing was mainly responsible for
plastic spread, as opposed to natural transport processes like erosion. Furthermore, small-scale lateral
to vertical heterogeneous distribution of macro- and microplastics highlights the need to determine
appropriate sampling strategies and the modelling of macro- and microplastic transport in soils
