应用混料回归设计，探讨了粳型杂交稻甬优538与粳型常规稻秀水134本田期氮化肥适宜施用比例，初步明确了施肥因子与产量的效应关系。结果表明，甬优538施肥因子对产量的作用效应大小为秆肥＞苗肥＞基肥＞穂肥，秀水134为苗肥＞基肥＞秆肥＞穂肥；甬优538的基肥×穂肥、基肥×苗肥×秆肥、基肥×苗肥×穂肥、苗肥×秆肥×穂肥，秀水134的基肥×穂肥、苗肥×秆肥、苗肥×穂肥、基肥×秆肥×穂肥等因子间互作具有显著的协同促进效应；在因子（∑xi=1）约束条件下，单因子比例水平与产量均呈抛物线关系，其中，对于这2个品种其穂肥曲线起伏幅度最大，不可过量施用；基肥、苗肥、秆肥、穗肥最优配比值，甬优538为31.0∶28.8∶21.4∶18.7，秀水134为24.9∶37.3∶11.5∶26.3。

By the mixed regression design, the appropriate ratio of applying nitrogen fertilizer for japonica hybrid rice Yongyou 538 and japonica variety Xiushui 134 in different stages in rice field were studied, and the relationship between factors and grain yields were defined initially. The result indicated that effects of nitrogen fertilizer were as follows: culm fertilizer（CF）＞seedling fertilizer（SF）＞base fertilizer （BF）＞booting fertilizer（BOF） in Yongyou 538; SF＞BF＞CF＞BOF in Xiushui 134. There were significant synergy enhancing effects among BF×BOF, BF×SF×CF, BF×SF×BOF, SF×CF×BOF in Yongyou 538; and BF×BOF, SF×CF, SF×BOF, BF×CF×BOF in Xiushui 134. Under the constraint condition of factor （∑Xi=1）, it showed a parabolic curve relationship between single ratio level and yield, in which the largest curve fluctuation of applying nitrogen fertilizer in booting stage was appeared both in Yongyou 538 and Xiushui 134. Therefore, over-applying nitrogen in booting stage should be avoided. The optimum ratio of applying nitrogen fertilizer is suggested as 31.0∶28.8∶21.4∶18.7 for Yongyou 538 and 24.9∶37.3∶11.5∶26.3 for Xiushui 134.