Evaluation of Phosphorus Leaching in an Agricultural Soil under Different Soil Amendments

The transport of Phosphorus (P) from agricultural soils to surface waters sensitive to eutrophication has long been a world-wide environmental concern. The intensive agricultural activity in the upper Shkodra fields, combined with others point source pollution, probably, intensify eutrophication of the Shkodra Lake. These Clay Loamy soils (calcaric Regosols) are characterized by low organic matter, N and P, with a high water percolation. An experiment was conducted at Greenhouse Research Station, Agriculture University of Tirana, Albania to evaluate Total P (TP) concentration in leaching and runoff waters. A three-month cultivation period of ryegrass (Lolium multiflorum) was studied in fourfold replication, while three successive harvests were accomplished under greenhouse conditions. Treatments comprised control soils (without amendment), soil with NPK fertilizer and soils amended with Straw and Biochar. Results of TP leaching tests showed continuous releases of P from fertilizer treatments (NPK without amendments treatment), while on the treatments with organic amendments (Biochar and Wheat Straw) were found to have had a weakened role on TP retention.