Abstract
Rice plant samples were grown in 14 cultivative pots under six different pH conditions of acid irrigation water (pH: 6.5, 6.0, 4.5, 3.5, 3.0, 2.5) and ion exchange water (pH: 7.5), in order to study an influence of pH of irrigation water on the tranfer of elements into rice plant from soils.
The acid irrigation water was prepared by adding mixed solution of 1 N H2SO4 and 1N HNO3 (1: 1) to ion exchange water. The rice grain yielded was separated into three parts, i.e., polished rice, bran and chaff, and they were powdered one by one.
The contents of twenty five elements in the three parts of grain (14 samples each) were determined by a neutron activation analysis. It was clarified that the contents of Cu, Zn, Fe, Cr, Mg, Rb, Mo, Ni, and Cs in the polished rice increased with decreasing pH of the acid irrigation water. The contents of Se and Br, on the contrary, decreased.
Significant changes of the contents were not observed for Na, AI, Sc, Mn, Cl, Ca, V and Co. The relationships between the contents of elements in the bran or chaff and pH of the acid irrigation water were not so clear as the case of bolished rice.
The enrichment factor of trace elements from soils was calculated for the polished rice, bran and chaff The high enrichment of Cl, Mo, Zn, Se and Cu was observed in the polished rice. Manganese and Cr were concentrated more in the bran than in the polished rice.
