Evaluation of total and bioavailable heavy metals and other soil-related variables in a rice paddy after the application of defecation lime

摘要

A two-year experiment was carried out in a paddy field to investigate the effects of the use of defecation lime derived from treated sewage sludge on soil total and soil phytoavailable heavy metals concentration. Heavy metals concentration was determined also in raw rice. Four treatments were arranged in a completely randomized block design: not fertilised (T0), organic fertilisation + chemical fertilisers (T1), defecation lime + chemical fertilisers (T2), defecation lime at pre-sowing (T3). For T3, the pH value increased significantly at the end of the second year, increasing from 5.8 to 6.11. T3 resulted in the highest soil organic carbon content (9.4 g kg(-1)), suggesting the potential of defecation lime both as soil corrective material and soil amendment. The application of defecation lime in the paddy field did not result in an increased phytoavailable amount of heavy metals in soil.