结果表明，该区域土壤有机质、全氮及各形态氮素含量呈现先降后升的趋势。
The result shows that the content of soil organic matter, total nitrogen and different forms nitrogen decreased firstly, then increased by time pasted.
土壤中的氮素主要以有机氮的形式存在于土壤有机质中， 土壤碳氮比与有机质含量显著相关。
The N in the SOM existed mainly in the form of organic nitrogen, and the soil C:N was significantly correlated with SOM.
下位叶比上位叶对土壤氮的供应状况更为敏感，随着施氮量的增加，水稻叶片氮素含量、叶绿素含量、SPAD值相应的增加，而下位叶的增幅更明显。
Leaf N/ chlorophyll content and SPAD value increased with the increasing N fertilizer, and the lower leaves were more sensitive to the soil N supply than the upper leaves.
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