Effects of Bio Product on Rice Growth, Rice Yield and Decreases in Cadmium Contents in Soil and Rice Grains

The aim of this research was to study the effects of chemical (CH) and bioproduct (MIC) fertilizers on rice growth (plant height), rice yield (full grains), and the decrease in cadmium (Cd) contents in soil and rice grains. A silty clay loam (SCL) soil for growing rice was prepared in the laboratory, with Cd addition and pH control. The relationship between CH and MIC fertilizer additions in various amounts with the reduction in the Cd contents of soil and rice grains was explored. As a result, the rice growth in the harvest phase and the yield increased from 138.80 ± 5.72 to 888.40 ± 2.38 cm⋅plant-1 and 689 to 888 seeds⋅plant-1, respectively, when the bioproduct was increased from MIC100 (0.625 L⋅ha-1) to MIC500 (3.125 L⋅ha-1). The Cd content in the soil during the harvest phase, 35.53 mg⋅kg-1, which was less than the standard value of 37.00 mg⋅kg-1 defined by the Pollution Control Department (PCD), Thailand, decreased when the bioproduct increased to MIC500. For the Cd contents in polished rice grains, when MIC500 was added, 0.19 mg⋅kg-1 of Cd was accumulated, which is acceptable according to the Codex Committee on Food Additives and Contaminants (CCFAC) threshold of 0.20 mg⋅kg-1 for Cd. Thus, MIC500 was the most effective in reducing the Cd accumulation in soil and rice grains and promoting rice growth among all MIC amounts.