Impact of manure and organic fertilizers on the quantity and content yield of heavy metals in spring rape

The pot experiment was set up with the split plot method in three repetitions in 2006. The objects of the first factor were the doses of manure and organic fertilizers to the soil in conversion to the brought in nitrogen (85 and 170 kg N·ha^-1), the objects of the second factor were the types of fertilizers: manure, sewage sludge and the composts prepared from sewage sludge. The soil used in an experiment was supplied from The Agricultural Experimental Station in Lipnik. The soil was taken from the arable layer, it has the granulometric composition of the light loamy sand.

The content of available phosphorus, potassium and magnesium formed on medium level, the pH_KCl of the soil amounted to 5.13. The soil was characterized by 0⁰ contamination of trace elements, which means that it contained the natural content of cadmium, copper, nickel, lead and zinc. Spring rape var. Licosmos was the test plant.

The aim of the research was the assessment of the influence of manure, sewage sludge and compost prepared from sewage sludge on yield quantity of seeds and straw and the content of cadmium, nickel, lead and zinc in spring rape.

The conducted research shows that fertilizers brought into the soil (manure, sewage sludge and compost prepared from sewage sludge) as well as two levels of fertilizing had a significant influence on the yield of the seeds and straw of spring rape. Manure, sewage sludge and compost prepared from sewage sludge played less significant influence on the decreasing or excessive increasing of heavy metals concentration in the seeds of spring rape. The double dose of fertilizers caused higher accumulation of heavy metals in the test plant. The straw of spring rape should be treated as a source of organic matter and the main nutrients for the soil. The highest concentration of copper, manganese, nickel and zinc in the straw of spring rape was noticed after the application of sewage sludge and of cadmium and lead after the application of compost prepared from sewage sludge.