Effects of increasing application doses of chicken manure ongrowth and some nutrient element contents of spinach and lettuceunder toxic conditions of cadmium and lead

This study was carried out to investigate the effects of chicken manure applied in increasing doses to soils with different cadmium (Cd) and lead (Pb) pollutants on the development of spinach and lettuce plants and some plant nutrient element content in greenhouse. For this purpose, increasing doses of chicken manure (0, 500, 1000 and 2000 kg da-1) were applied to pots treated separately with cadmium (0, 10, 20 mg kg-1) and lead (0, 20, 40 mg kg-1). After 60 days of incubation, the lettuce and spinach were grown in pots and the effects of the applications were evaluated by leaf and root analyses. Increasing lead doses only caused a decrease in the dry weight of lettuce roots, while cadmium doses reduced leaf and root dry weight yields of spinach and lettuce plants, the decrease was more evident in the spinach roots. Cadmium was found to increase depending on the doses, in Spinach leaves; 0,58; 65,71 and 75,04 mg Cd kg-1; as for the roots; 1,23; 108,10 and 162,17 mg Cd kg-1. In lettuce the values are; in the leaves; 0,54; 33,10 and 39,52 mg Cd kg-1; in the roots; 0,41; 44,19 and 68,50 mg Cd kg-1. Lead too increased depending on the dose, in spinach leaves; 1,44; 2,04 and 2,40 mg Pb kg-1; in the roots of 1,14; 3,23 and 8,29 mg Pb kg-1. In lettuce leaves; 0,54; 2,19 and 2,46 mg Pb kg-1; in the roots; 7,62; 13,35 and 17,48 mg Pb kg-1. Macro and micro plant nutrient element contents and amounts absorbed have been affected depending on the increased cadmium and lead doses, especially Fe, Cu, Mn, Cd, Pb and Cr have been found to accumulate more in plant roots. It has been observed that cadmium and lead are below the critical concentrations determined for human consumption in control plants, but with the applications, these plants contain heavy metals far above the critical limit. It has been concluded that although applied manure increases the leaf and root dry weight yield of plants compared to control, it is not effective in bringing high heavy metal concentrations below toxic limits.