The use of geotextiles in agricultural soils and their effects on soil properties and nutrients availability. Are wastes plastics likely to become useful materials in agriculture?

Abstract

Experiments were conducted in agricultural soils of central and northern Greece to simulate agricultural practices and to study the effect of geotextile particles on the physical and chemical properties of the soils. Geotextile was added to soil samples in different shapes, dimensions, and proportions (1, 2, and 4% v/v), which remained for different periods (10, 25, 50, 150 days). The physicochemical properties and their changes after adding the geotextile were determined in soil samples. Furthermore, the levels of nutrients in the soils and their changes were evaluated concerning the levels of added plastic and the time they remained in the soil. Once the plastic dimensions were sufficiently large (>5 mm), the changes in the organic matter content and the available trace elements concentration were most pronounced. Plastic residence time appears to be crucial, as the greatest changes in both exchangeable potassium and assimilable phosphorus were observed in the soil samples when the plastic was introduced at the microplastics dimensions (<5 mm), in its maximum amount (4% v/v), and remained within the soil over the longest time (150 days). Knowledge of the chemical composition along with the chemical behavior of plastics used in agricultural practices is particularly important, as it can lead to real benefits to the agricultural economy, being able to regulate the uptake and availability of nutrients already present bound in soils, and reducing the need for continuous need for fertilizer addition, in a circular economy approach.