沿海沙地小叶龙竹林凋落物分解及养分归还动态

Dynamics of litter decomposition and nutrient return of Dendrocalamus barbatus forest in the coastal sandy site

对沿海沙地小叶龙竹林的凋落物及养分月动态特征进行连续观测分析,研究结果表明,竹林凋落物量月动态波动较大,峰值分别出现在2004年10月、2005年4月和9月,2005年1月和7月处于低谷.凋落物各营养元素组分平均值大小为N>K>P.N、K养分含量月动态变化幅度相对较大,P变化相对平稳.凋落物N年归还总量最高,K年归还量次之,P年归还量最低.凋落叶分解速度最快,分解6个月残留率为51.43%,竹枝分解速度最慢,6个月后残留率为83.27%.分解1 a后竹叶残留最少,笋箨其次,竹根残留的最多.应用二次方程对小叶龙竹各器官分解剩余量与分解时间的关系进行拟合得出模拟方程.

Through continuous litter and nutrient monthly dynamics observation of Dendrocalamus barbatus forest in coastal sandy site, it was revealed that the bamboo forest litter monthly dynamic had larger fluctuation, the peak presented in the October of 2004, April and September of 2005 respectively, and less in the January and July of 2005. The average values of components of nutrient elements in the litter were N 〉 K 〉 P. The N, P nutrient concentrations of the litter monthly fluctuated distinctly and the P was stable. The biggest of the litter annual return dynamics was N, the P annual return dynamics took the second place, and the least was K. The decomposing speed of leaf in litter was the fastest, whose remaining rate was 51.43% after six months, and the twing in litter was the slowest, whose remaining rate was 83.27%. The residue of bamboo leaf was the least, sheath in litter took the second place, and bamboo root was the most. The simulation equation was obtained by applying quadratic equation to the relation of decomposition surplus and time of the organ of D. barbatus.