Effects of Different Rhizosphere Sizes on the Growth, Distribution Patterns and Utilization of Nitrogen Fertilizers of Different Varieties of Rice Plants (Oryza Sativa L.) on the Same Hill

[摘要] In order to clarify the inter-hill competition at the maturing stage. Using the tracer 15N method. The growth characteristics of rice plants (Oryza Sativa L., cv. Suweon no. 258 and TKM-6) grown in pots of different sizes were examined. The top dry weights of two varieties, TKM and Suweon planted on the same hill were 82.84% and 16-18%, respectively. In Suweon, the ratio of culm dry weight did not change with rhizosphere size, but the ratio of leaf blade dry weight to the total weight increased with decreasing rhizosphere size; whereas the ratio of the dying organ dry weight showed an opposite behaviour. The percentage of nitrogen content increased with increasing rhizosphere sizes in two varieties, with a greater increase in Suweon. The percentage of nitrogen contents in TKM was higher than that in Suweon in smaller rhizospheres, but in larger rhizospheres Suweon showed a higher percentage of nitrogen than in TKM. The ratio of recovery of 15N top-dressing in basal-dressing plot was 51-79%, at the panicle formation stage plot, 51-59%, and at the reduction division stage plot, 63-78%. Further-more, lager pots and later nitrogen supply showed a high nitrogen content. The ratios of 15N content in the two varieties in basal-dressing plot were 74-84%, and top-dressing at the tillering stage save 76-83%. With TKM top-dressing at the reduction division stage, they were 80-85%, a very high rate of recovery of nitrogen. Partition of 15N content of ears in each top-dressig time in the basal-dressing plot was 37-62%, the tillering stage 53-71%, at the panicle formation stage 63-67%, and at the reduction division stage 54-67%. These results revealed that smaller rhizospheres led to a cleary high partition of nitrogen.

[学科分类] 农业科学（综合）

[关键词] Inter-hills competition;株内相互作用;^<15>N;重窒素(15N);Oryza Sativa L.;水稲 (Oryza sativa L.);Partition of Nitrogen;窒素分配率