Abstract:

The contents of 9 nutrient elements (N、P、K、Ca、Mg、Cu、Zn、Mn、SiO₂) in stem-flow, rainfall were measured in 4 tree species at 22～25-year-old grown in Zhuzhou, Hunan Province, such as Cinnamomum camphora、Liquidambar formosana、Eucommia ulmoides、Osmanthus fragrans from April of 2003 to July of 2004. The results showed that the content's of the nutrients in rainfall varied according to the month;the content sequence of the nutrient elements in precipitation were as follows: Ca>SiO₂>Zn>NH₄⁺-N>K>NO₃^--N>Fe>Mg>Mn>P>Cu; the content of the nutrients in stem-flow also varied in the same way and changed seasonally; compared with rainfall, most of them increased. The nutrient characteristics of stem-flow for different tree species were different significantly, the content sequence of the total nutrient elements in stem-flow was as follows: Liquidambar formosana、Eucommia ulmoides、Cinnamomum camphora、Osmanthus fragrans. The proportions of nutrient in stem-flow of different tree species also varied significantly, among all analysed nutrients, the content was found highest for K、Ca、NH₄⁺_N、SiO₂, middle for NO₃^--N、Mg、Mn、Zn, and lowest for Fe、P、Cu; the contents of Fe and Zn in stem-flow were lower than those in rainfall, significant variation was especially noted for Zn in the four tree species.

Key words: Cinnamomum camphora, Liquidambar formosana, Eucommia ulmoides, Osmanthus fragrans, through-fall, stem-flow, nutrient content