不同坡位杉木—闽粤栲混交林及杉木纯林养分循环特征的比较

选择福建省建阳范桥国有林场16 a生杉木—闽粤栲混交林与杉木纯林为研究对象,进行不同坡位不同林分养分循环特征的比较分析,结果表明：杉木—闽粤栲混交林与杉木纯林养分存留量差异明显,混交林中坡和下坡分别比杉木纯林高28.16%、19.39%;各个坡位养分归还量均表现为：混交林〉杉木纯林,混交林下坡的养分归还量最大,其次是上坡,再次为中坡;中坡和下坡养分吸收量分别是杉木纯林的1.29、1.49倍;同一坡位同一林分的养分归还比表现为：N〉P〉K,说明养分N在两林分中的循环能力最强。混交林在上、下坡的归还比分别比杉木纯林高160.0%、104.55%,而二者在中坡的差异则较不明显,混交林养分归还比表现为：下坡〉上坡〉中坡,说明混交林下坡的养分循环能力最强。

Effect of slope position on nutrient cycling of Chinese fir plantation and its mixed forest with Castanopsis fissa

The plantations of 16 year-old Chinese fir and its mixed forest with Castanopsis fissa were chosen as research object in Fanqiao National Forest Farm in Jianyang of Fujian Province,and the nutrient cycling characteristics of different forest stands at different slope position were determined and analyzed.There was obvious difference in retention of nutrient elements between the Chinese fir plantations and the mixed forest.Retention of nutrient elements of the mixed forest at the middle slope and lower slope positions was respectively higher than the pure plantations by 28.16% and 19.39%.The nutrient return of the mixed forest was higher than the Chinese fir plantations at all the slope positions.The nutrient return of the mixed forest was the most at the downslope position,followed by the upper slope position,the least at the middle slope position.The annual nutrient uptake of the mixed was 1.29 times and 1.49 times more than the Chinese fir plantations at the middle slope and lower slope positions.Compared with P and K,the intensity of the cycle of N was the strongest.The ratios of nutrient return of the mixed forest were 160.0% and 104.55%higher than those of the pure Chinese fin plantations at the upper and lower slope positions,respectively,but the difference at the middle slope position was insignificant.In the mixed forest,the ratios of nutrient return appeared to be lower slopeupper slopemiddle slope.It has been proved that the total nutrient cycling capability in the mixed forest was the highest at the lower slope position.