Growth of Carya illinoinensis (Wangenh) K. Koch seedlings in a polluted soil remediated with an organic amendment

The pollution of the Moron stream causes degradation of its soil margins, other natural resources and the quality of life of people living nearby. Organic amendments that are low in potentially toxic elements (PTE), can be used as a sink for reducing the bioavailability of pollutants in contaminated soils through their effect on their adsorption, complexation, reduction and volatilization. Besides, they are a valuable source of organic matter, macro- and micro-nutrients for plant growth. The aim of this study was to evaluate the growth of Carya illinoinensis (Wangenh) K. Koch seedlings in the polluted soils of the margins of the Moron stream amended with different doses of biosolids. Biosolids were obtained from the local wastewater treatment plant. Pots containing the biosolids-amended soils (B3, 3% of biosolids; B6, 6% of biosolids; B9, 
9% of biosolids), an unamended polluted soil (B0) and a good quality soil (GQS) were sown with a seed of C illinoinensis for 5 months. Plants grew well, showing no visible sign of toxicity. At the end of the experimental period, stem, leaves and roots (DW) were oven-dried at 65°C for 48 h and weighed (DW) for biomass determination. Soil electrical conductivity and soil pH were determined by standard procedures. No significant differences were observed in roots DW between treatments. Leaf biomass followed the order GQS≥B3 ≈B6 ≈B9 ≈B0; stem biomass was GQS≥B3 ≈B6≥B9 ≈B0; electrical conductivity was GQS≥B6 ≈B9>B3>B0, whereas soil pH followed the order B0≥B3 ≈B6≥B9>GQS. The results of the present study suggest that 3 or 6% of biosolids amendment may be used for the growth of Carya illinoinensis seedlings using the polluted soil of the margins of the Moron stream.