Field studies were conducted with Kusabue variety and factorial design of 12 treatments composed of 3 levels, 10 ㎏, 15 ㎏ and 20 ㎏ of N per 10 a, and 4 levels of 80, 100, 120, and 140 hills per 3.3 ㎡ plot in reclaimed salty area having an average of 0.48 % salt concentration.
The law of spacing effect was observed in the increase of the number of stems at any application levels of N, and the increased N application exceeding 15 ㎏ N per 10 a did not increase the number of stems in maximum tillering stage. The light recieving efficiency of plant population was greatly reduced by close planting when compared with the effect of increased N applications in heading stage.
The spacing effect on the C/F ratio was not noted but was reduced markedly by the increased N applications, accordingly the spacing effect on rough rice yields to the LA was less than by the increase N application. Closer spacing increased the number of panicle, and non-effective stems, decreased the number of grains per panicle and panicle weight.
The increased N applications also increased the number of panicle, reduced the weight of 1,000 grains and the ratio of matured grains. It is recommended to plant 100 hills per 3.3㎡ with the application of 15 ㎏ N per 10 a in the reclaimed salty area of Korea.
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