氮素指数施肥对夏蜡梅幼苗生长、养分分配的影响

【目的】筛选适合夏蜡梅生长的最适施氮水平,为夏蜡梅规模化育苗生产提供技术参考。【方法】设置0、149、273、412、550 mg/株5个氮素水平处理,对夏蜡梅1年生苗进行指数施肥试验,观测其形态指标。【结果】在施氮量为149~412 mg/株时,夏蜡梅幼苗的形态指标随着施氮量的增加而增加,夏蜡梅幼苗的形态指标都随之提高。当施氮量超过412 mg/株,氮肥过高后,苗木的形态指标趋于稳定。当施氮量为149~412 mg/株,氮、钾素在根茎中的分配比率随着氮量的增加而提高,在叶中的分配比率随之降低;磷在根茎的分配比率降低,在叶中的分配比率上升。当氮素施用量为412 mg/株时,夏蜡梅幼苗的氮、磷、钾养分含量最高。当氮素施用量为149~273 mg/株时,氮素吸收利用效率最好。【结论】273~412 mg/株的氮素指数施肥最有利于夏蜡梅幼苗的生长,且6—7月是夏蜡梅生长的高峰期,在此期间施肥效果较好。

Effects of nitrogen exponential fertilization on growth and nutrient distribution of Sinocalycanthus chinensis seedlings

Objective]This paper provides the theoretical background for selecting the ideal nitrogen level for Sinocaly-canthus chinensis seedlings and conducting nursery production on a large scale. Method]Exponential fertilization using nitrogen was conducted for S. chinensis seedlings at five levels (0, 149, 273, 412 and 550 mg/ tree). Result] The seedling morphology indices related to growth rate increased with an increase in the N application rate when nitrogen lev-els were between 149-273 mg/ tree. The morphological indicators tended to be stable when the N supply was higher than 412 mg/ tree. Between nitrogen levels of 149-273 mg/ tree, the distribution ratio of N and K in the roots and stems in-creased with an increase in the nitrogen application rate, while that of P decreased; however, the distribution ratios of N and K in the leaves decreased, while that of P increased. The highest N, P and K nutrient contents of the seedlings were observed when the nitrogen application rate was 412 mg/ tree. The highest nutrient absorption and utilization efficiency results were observed for nitrogen levels of 149-273 mg/ tree. Conclusion]Exponential fertilization using nitrogen at lev-els of 273-412 mg/ treewas most beneficial for seedling growth, and June and July were the peak months in which stron-gest effects of fertilization on seedling growth were observed.