2005 Volume 74 Issue 3 Pages 270-275
The root-system development of two rice varieties, Koshihikari and Kichinkurogome, fertilized with ammonium nitrogen was compared with that of these varieties fertilized with nitrate nitrogen. In both varieties, dry weight, root length and the number of nodal roots were significantly greater in the plants fertilized with ammonium nitrogen than in those fertilized with nitrate nitrogen. However, specific root length was significantly longer in the plants fertilized with nitrate nitrogen in both varieties. The above effects of the chemical form of fertilizer nitrogen on the root system were greater in Kichinkurogome than in Koshihikari. These findings suggest that the growth of rice fertilized with ammonium nitrogen is superior to that fertilized with nitrate nitrogen in increasing root-system length. The difference in the root-system length may depend on the difference in the number of nodal roots rather than the degree of root branching. The effect of the chemical form of fertilizer nitrogen on root system development was suggested to vary with the rice cultivar.
