Heavy metal concentration in grains and soils as influenced by organic, integrated and chemical source of nutrition in maize-wheat system

The long-term experiment with maize-wheat sequence was initiated during 1996–97 at the experimental farm of the department of Agronomy, Agrometeorology and Forestry, Punjab Agricultural University, Ludhiana. On the same field the investigation was expanded to organic (pure), integrated (partial) and chemical farming systems during Kharif and rabi 2002–03. The application of farmyard manure, green manure and crop residues decreased heavy metal (lead, nickel and cadmium) concentration in grains of maize and wheat as well as in soils and uptake of heavy metal by maize and wheat grains as compared to use of chemical fertilizers alone as a source of nutrients.