不同人工施氮量对荆条氮素利用的影响

Effects of nitrogen absorption of Vitex negundo in different nitrogen fertilization levels

为了解植物在不同氮生境下的响应,以太行山丘陵区荆条群落为对象,采用人工施氮的方法,研究不同施氮水平下荆条氮素利用特征。结果表明:1)人工施氮后,成熟绿叶和枯叶中氮质量分数随施氮量的增加而增加,并在施氮量为32 g/m2时达到最大值,施氮对成熟绿叶磷质量分数也有明显的影响,当施氮量为8 g/m2时,叶中磷质量分数最高,约为对照的2.29倍,施氮量与枯叶中磷质量分数无显著相关关系;2)施氮能显著降低荆条的氮素回收率,随施氮量增加,氮素回收率整体上表现出负相关,平均降幅约为18.57%,施氮量在4～8 g/m2之间时,氮素回收率无显著差异;3)随施氮量提高,土壤氮和磷的质量分数呈现升高的趋势,土壤磷质量分数在施氮量为4 g/m2时达到最大值,之后随施氮量的增加而下降,土壤有机质和土壤含水量与氮素回收率呈负相关关系。

Taken Vitex negundo community in Taihang mountainous region as object,this paper studied the effects nitrogen absorption of Vitex negundo in different nitrogen fertilization levels.The main purpose of this paper is to discover the response of plant to different nitrogen environment.Results showed that：1） Both the contents of nitrogen in mature and withered leaves increased with increased nitrogen fertilization level,and the maximum values occurred at 32 g/m2 nitrogen fertilization level.Nitrogen fertilization had obvious effects on the content of phosphor in mature leaves with the maximum value being at 8 g/m2,which was 2.29 times that of control.Whereas it had nothing to do with the content of phosphor in withered leaves.2） Nitrogen fertilization could lead to the decrease of nitrogen resorption efficiency of Vitex negundo.The nitrogen fertilization was negatively correlated with nitrogen resorption efficiency,average decrease being up to 18.57%.But when nitrogen fertilization level was 4-8 g/m2,the change of nitrogen resorption rate was not obvious.3） The content of nitrogen in soil increased with increased nitrogen fertilization level.The maximum value of phosphor content in soil was at 4 g/m2 nitrogen fertilization level,and the content of phosphor decreased after that point.Nitrogen resorption efficiency of Vitex negundo negatively correlated with soil organic matter and soil moisture content.