Long-term application of biowaste compost versus mineral fertilization: Effects on the nutrient and heavy metal contents of soil and plants

In recent years the use of biowaste compost (BC) as a soil amendment is of increasing interest. The aim of the experiment was to investigate the influence of different fertilization systems: biowaste compost, annual average of 32 Mg ha(-1) BC (fresh matter) and mineral fertilizer (83:52:95 kg ha(-1) NPK fertilizer) on the nutrient and heavy metal contents of soil and plants. Soil samples (1997) and harvest products (1996-1998) from a field trial (initiated 1992) were analyzed for K, Mg, P, Cu, Mn, Mo, Zn, Cd, Ni, and Pb. The five-year fertilization with composted biowaste did not influence the total contents of Cd, Mn, Mo, and Ni in soil. The total soil contents of Zn and Pb were significantly higher in soils of the BC treatment than in the unfertilized control. Both fertilized plots tended to have higher Cu and Zn contents in harvest products than the unfertilized control. The mineral fertilization inhibited the Mo uptake by plants. In 1998 the mineral fertilization led to higher, and the biowaste, compost application to lower, Cd contents in potato tubers as compared to the control.