Abstract: Effect of different application rate of urea on the rice growth and N fertilizer utilization ratio under water leakage and nonleakage conditions was studied by, ¹⁵N trace technique in the greenhouse. The results indicated that hitrogen fertilizer played an important role in the growth of rice. The accumulative amount of dry matter of each organ at different growing stages increased with the application rate of urea. Soil water condition affected the growth of each organ, rice yield and N fertilizer utilization ratio greatly. The root growth of rice was seriously in hibited, and the accumulative amount of aerial part and N absorbed by rice decreased due to long-term submerged status of soil, which the N fertilizer utilization ratio ranged from 18. 66 % to 35. 67 %. The rice growth and N fertil izer utilization ratio under the water leakage condition were relatively superior to that under the nonleakage condi tion, and the N fertilizer utilization ratio reached 42. 0%-65. 8%. There was similar trend about the decrease of utilization efficiency of N with the increase of N fertilizer under two kinds of soil water conditions. The recovery of ¹⁵N applied as hasal fertilizer was lower relative to that applied as topdressing fertilizer. The priming effect of fertil nation in the experiment reached 18% of total N contribution ratio under the nonleakage condition higher than that of water leakage condition (5.1%). The remains of N in soil profile 0-80 cm were below 10% of application rate of urea.

Key words: fertilizer, utilization ratio, urea, water leakage condition

摘要： 利用¹⁵N示踪技术在温室中研究了无渗漏(长期淹水)和渗漏条件下氮肥施用量对水稻生长和氮肥利用率的影响。氮肥对水稻地上部和根的生长起重要作用。水稻不同生育阶段各器官干物质积累随施肥量增加而提高。土壤的渗漏状况也强烈影响水稻各部分生长及氮肥利用率。长期淹水条件下，水稻的根系生长受到抑制，地上部积累量下降，氮肥利用率为18.66%～35.67%；在渗漏条件下，水稻的生长状况相对较好，氮肥利用率达42.0%～65.8%。水稻对氮肥的利用率随氮肥用量的增加而减少，作为基肥施用¹⁵N回收率比追施低。长期淹水条件下氮肥的激发效应为18%，高于渗漏条件下的5.1%。0～80 cm土壤剖面中残留的肥料氮低于总施用量的10%。

关键词: 尿素, 水分渗漏, 肥料利用率