以穗型直立的紧凑型水稻品种沈农07425和穗型弯曲的松散型水稻品种秋光为材料,在不同氮素水平下研究两种株型品种的土壤硝化-反硝化作用强度.结果表明,施氮条件下不同株型品种的土壤硝化作用强度存在差异,紧凑型沈农07425施氮处理的硝化作用强度随施氮量增加而增强,最大值为齐穗期高氮处理,分别较低氮、中氮处理及PK和CK处理高18.87％、16.53％、60.29％和56.60％；而松散型秋光施氮处理以分蘖期低氮的硝化作用强度最大,较中氮、高氮处理高13.32％和3.05％,但比PK和CK处理小21.27％和27.37％.施氮条件下紧凑型沈农07425与松散型秋光的反硝化作用强度表现一致,施氮水平越高,反硝化强度越大.齐穗期反硝化作用强度最大,此时两品种施氮处理的反硝化作用强度分别比PK和CK处理高24.20％～63.04％和50.29％～77.90％.相关分析说明,不论紧凑型品种还是松散型品种,为减少硝化-反硝化氮素损失,应强调在拔节期追肥.%The compact rice Shennong 07425 with erect panicle and the loose rice Akihikari with curved panicle were used to study nitrification -denitrification intensity of paddy soil under different nitrogen levels. The results obtained were described as follows. The two different plant species showed differences on nitrification intensity under nitrogen treatments. Nitrification intensity of soil in Shennong 07425 increased with nitrogen level and it reached the maximum in high N level at full-heading stage. Nitrification intensity in high N level was 18.87%,16.53%,60.29% and 56.60% greater than that of low N level, middle N level and PK、CK at that time. But it achieved the maximum under low N level at tillering stage in Akihikari, nitrification intensity in low N level was 13.32% and 3.05% superior than that of middle N level and high N level, and 21.27% 、27.37% lower than PK、CK. There was the same trend of denitrification intensity between Shennong 07425 and Akihikari, the N level was more bigger, the denitrification intensity was more stronger. The two varieties attained the biggest denitrification intensity at full-heading stage, denitrification intensity under N levels exhibited 24.20% -63.04% and 50.29%-77.90% higher than PK、CK respectively. The correlation analysis suggested that nitrogen fertilizer should be applied in jointing-booting stage for both rice in order to decrease the loss of N by nitrification-denitrification.
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