DIFFERENCE IN NATURAL ABUNDANCE OF ^<15>N IN SEVERAL RICE (Oryza sativa L.) VARIETIES : APPLICATION FOR EVALUATING N_2 FIXATION

概要

論文の詳細を見る
The natural abundance of ^<15>N in rice grown in a flooded rice soil was determined to evaluate varietal differences. In some trials at the International Rice Research Institute (IRRI), statistically significant differences in grain ^<15>N abundance were observed. The δ^<15>N values of the grains ranged from 5.2 to 10%, depending on the fields and the coefficient of variation was 6-9%. The difference between the maximum and the minimum δ^<15>N values in the grains of several rice varieties was 22% of the mean value of δ^<15>N. IR42 grains had a lower δ^<15>N value than the OS4 grains. The grains exhibited a higher ^<15>N abundance than straw and roots in all the varieties except one. The ^<15>N abundance in available soil N increased with the soil depth. Grains had a lower ^<15>N abundance when grown in pots with a bottom than when grown in the field where, the rice roots penetrated into deeper layers. When grown in pots, the δ^<15>N value of the grains was lower than that of available N in the surface soil. It is, therefore, recommended to grow test and reference varieties in pots with a bottom so that possible differences in rice varieties with regard to their dependence on biological N_2-fixation may be revealed.
社団法人日本土壌肥料学会の論文