Abstract:
Reclaimed-mining soil (RMS) is characterized by low fertility, acidic pH,
and high heavy metal contents. As a result, adding amendments becomes
essential to support plant growth. Therefore, this research measured
alterations in the characteristics of RMS, plant growth, and metal
accumulation in plants with the co-application of coal fly ash (CFA) and
empty fruit bunches of oil palm (EFBOP). In the first experiment, various
levels of CFA (0, 75, and 150 Mg ha-1) and EFBOP (0, 25, and 50 Mg ha-1)
were added to the RMS and then incubated at 70% water holding capacity
for 45 days to determine their effect on changes in soil properties. In the
second experiment, four treatments: control, CFA, EFBOP, and
CFA+EFBOP were tested in the greenhouse to quantify their effects on the
growth and metal accumulation of plants. Results of the study showed that
the co-application of CFA and EFBOP significantly affected bulk density,
pH, mineral nitrogen (NH4
+ and NO3
), available phosphorus, and
exchangeable Ca and Mg in RMS. CFA application increased exchangeable
Al by 82-160%, while EFBOP resulted in a decrease of 24-119%. CEC
decreased with CFA application and increased with the use of EFBOP. Plant
growth increased with the co-application of CFA and EFBOP. The addition
of CFA to soils results in increasing metal contents in plant tissue; however,
the presence of EFBOP reduced the concentrations of metal in plant tissue.
These results highlight the potential of CFA and EFBOP, which are industrial
and agricultural wastes, as valuable soil amendments.
