The result of the experiment with ~(15)N labbeling shows that tatolamount of nitrogen (N) absorbed by rice plants is about 2/3 from soil N and 1/3from fertilized N Compared with once fertilizing, rate of fertilized N in riceplants with several fertilizing decreased. 74.1% of fertilized N at vegatativephase concentrated in stems and leaves, and 63.4% in grains at reproductivephase. Grain yield is in relation to both the A_N value of soil and soil N abs.orbed but not in relation to the fertilized N or its uti...
