The effect of prolonged release mineral fertilizers coated with co-polyester films from pet waste recycling on maize plants.

The paper presents researches carried out in order to test complex mineral fertilizers coated with biodegradable co- polyester films using as raw material the polyethylene terephthalate (PET) waste, such as plastic bottles for food. Achieving of biodegradable coatings, based on polyethylene terephthalate, requires modifying the chemical structure of aromatic polyester (PET) with dicarboxylic acids (aromatic and / or aliphatic), and / or other polyols, to create a biodegradable capsule for prolonged release mineral fertilizers. In order to highlight capacity of complex mineral fertilizers coated with co-polyester films, to releasing nutrients in the soil in an extended time period, unlike common complex mineral fertilizers, a green house experiment was organized. Soil material used was collected from two contrasting soil types in terms of physico-chemical characteristics, namely Luvic Phaeozems, and Calcaric Fluvisols. The experimental variants were set up in vegetation pots of about 20 kg soils / pot capacity, in which fertilizer materials were introduced, namely co-polyester films coated complex mineral fertilizers (N15P15K15) and regular granular complex mineral fertilizers. The crop was very early PR39D81 hybrid corn with excellent resistance to drought (hybrids belonging to the group FAO 200). For all measured phenological parameters: plant height, plant weight, root weight, cobs weight, grain weight and grain number, were recorded very significant increases in the values of the fertilized variants as compared to unfertilized, controls, variants of both soil types. The best results were obtained on Luvic Phaeozems soil where average size of maize plants at flowering stage was 29 cm higher in the variant fertilized with co polyester film coating complex mineral fertilizers, and 6cm higher in the variant fertilized with usual formula mineral fertilizers. Data obtained in this experiment showed that the effects generated by the use of complex mineral fertilizers coated with co polyester films in the proposed formula has been beneficial for the development of maize plants in a measure at least as high as in the classical variant of fertilization.