| The experiments were conducted in the farm of Agricultural Institute of Yangzhou University in 1999?000, with the material of two-line indica hybrid Lianyoupei 9 and convential Japonica Wuyunging 8 released, recently. Three denstise:0.5* ~ hills, per 666.6m2(33.3*4Ocm), 1.0*104 hills per 666.6m2(33.3*2Ocm), 1.5* 104 hills per 666.6m2(33.3* 13.3cm) were designed and each hill includes 1, 2, 3 plants respectively, contrasting to 2.0* ~ hills per 666.6m2 which used as CK in these experiments, which resulted in 10 treatments(illustrated by 0.5/1, 0.5/2, 0.5/3, 1.0/1, 1.0/2, 1.0/3, 1.5/1, 1.5/2, 1.5/3, CK)and 60 plots totally. The areas of each plot was lOin2, associate with three nitrogen levels including 15.2kg N/666.7m2, 17.5 kg N/666.7m2, 19.8kg N/666.7m2 for Wuyuging8. That for lianyupei9 were 7.6 kg N/666.7m2 9.9kg N/666.7m2 and 12.2kg N/666.7m2 respectively, the ratios of N applied was 40 percent basal nitrogen and 60~-70 percent of total nitrogen application in middle growing stage. Dynamic development of the number of stems and tillers are varied under different density circumstance. The maximums number of stem and tillers appeared at jointing, but it was lower than that of CK. High productive tiller rate is the character of sparsely cultive rice, so the tiller?panicles accounted for 95 percent of total panicles, due to more nitrogen applied in middle growing stage. Improving management, raising effective tillers rate enhancing nitrogen application during middle stage are key approaches for sparsely culture rice. Total number of leaves of rice stem in sparse cultivation was more than that of traditional dense culture rice. Leaf areas index, especially the leaves attached to culm are large, ratios of top three leaves抋reas distribution of leaves are different between the two varieties , japonica variety Wuyuging 8 appears indica Lianyoupei 9 appears.choralee content in leaf was high, due to more nitrogen applied in middle growing stage, so high photosynthetic efficiency can be observed after heading 47 ~J+V,k~ 2001 ~?~Li~ The composition of yield indicated that 1.0/2 of Wuyuging8 has the highest yield of 707.1 0kg1666.6rn2, 1.0/1 of Lianyupei 9 has the highest yield. Average yield was 1.0>1.5>0.5. 0.5~104hil1s per 666.6rn2 has the lowest yield among all treatments, because of number of panicle was too low. On the condition that the number of rice hill per unit land areas were same, each hill contains productive tillers were about 17?0, so that both panicle number pe unite and the size of panicle were same, too, no significant variation of yield were found. For the treatment of 1.5* ~ hills per 666.6m2, dense canopy that results from excess tiller and nitrogen applied at middle growing stage lead to unproductive tillers compete for resources, such as solar energy and mineral nutrients--particularly N, with tillers that later produce panicles. Lodging were occurred during later filling stages which was another cause of low yield in 2 1.5*104 hills per 666.6m More dry matter produced and accumulation of spares culture rice than that of dense culture rice were found. The amount of dry matter amassed from heading to ripening accounted for large ratio of that of t9tal biomass, so that a high harvest index could be obtained in sparse culture. Nitrogen uptake by thin culture rice were verified according with the yi...
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