The Effect of Organic Fertilizers with Addition of Pb and Cd On the Changes of Soil Chemical Properties and Growth of Spinach Plants in Inceptisols.

This experiment aims to investigate the effect of organic fertilizers with addition of heavy metals of Pb and Cd on the changes of soil chemical properties and the growth of spinach in Inceptisols.  The experiment is conducted in green house using the Inceptisols in the period from June 2009 to December 2009. The research applies randomized group design using 8 treatments with 3 repetitions (24 treatments in total). The treatments include treatment without fertilizer as a control, treatments with market waste compost, rice straw compost, cassava leaf compost, corn leaf compost, cow manure compost, chicken manure compost, and sheep manure compost. The results show that the organic fertilizers treatments affect significantly the C-organic, Cd uptake, Pb total in soil, cation exchange capacity (CEC), and Spinach harvest. The treatments do not affect significantly the Cd total in soil and uptake Pb of Spinach. The smallest uptake of Cd occurs on the market waste compost (9.49 mg/Kg) compared to the other treatments and the control (20.60 mg/kg). The result  indicates that market waste compost treatment can support Cd chelation in soil through the changes of soil chemical properties. Generally, this research finds that the organic fertilizers treatments affect the changes of the soil chemical properties which reduce the heavy metal adsorptions in spinach. The characteristics of the organic fertilizers treatments determine the amount of the heavy metal of Pb and Cd that can be chelated in the soil.

Keywords: Pb,  Cd, organic fertilizers, heavy metal chelation, spinach