茂兰喀斯特原生林凋落物及矿质元素归还动态*

植物生长所需的大部分矿质元素均来自于凋落物归还给土壤的物质再循环,本研究对茂兰喀斯特原生林凋落物及矿质元素归还动态进行了定位观测。结果表明,凋落物年总凋落量为5248.6±838.5 kg.hm-2^,叶凋落量占总凋落量的68.2%,总凋落量与叶凋落量的凋落节律均呈双峰型,花果等的月凋落量与月均温度及月降水量均呈极显著正关性。原生乔木林叶凋落物中K、Ca、Mg、Fe、Mn、Zn、Na 7种矿质元素的月含量呈不规则变化,含量大小为Ca﹥Mg﹥K﹥Mn﹥Fe﹥Zn﹥Na。叶凋落物中K、Ca、Mg、Fe、Mn、Zn等矿质元素的月归还量与叶凋落物量的月动态相关性极显著。叶凋落物中Ca、Mg、K、Mn、Fe、Zn、Na的年归还量分别为89.03、13.03、10.01、0.82、0.77、0.14、0.07 kg.hm-2^,7种矿质元素的年归还量大小与其年均含量大小极显著正相关。

Litterfall and mineral elements dynamics of primary forest in Karst area of Maolan, Guizhou Province, China.

Most of the mineral elements required by plants come from nutrient recycling by returning litter to the soil. Litterfall and mineral elements dynamics of primary forest in Karst area of Maolan were studied in Karst area of Libo, Guizhou Province, China. Results show that the averaged annual litterfall biomass was 5248.6±838.5 kg.hm-2^.The leaf litter accounted 68.2% of the total litterfall. The monthly litterfall dynamics of leaf litter and total litterfall exhibited a bimodel distribution. The monthly litterfall of flowers and fruits showed a highly significant positive correlation with monthly average temperature and precipitation.The monthly concentration of K, Ca, Mg, Fe, Mn, Zn and Na in the leaf litter of primary forest showed irregular changes, with the concentration in the order Ca>Mg>K>Mn>Fe>Zn>Na. The monthly return of mineral elements such as K, Ca, Mg, Fe, Mn, Zn in leaf litter is highly correlated with the monthly dynamics of leaf litter. The annual returns of Ca, Mg, K, Mn, Fe, Zn, and Na in leaf litter were 89.03, 13.03, 10.01, 0.82, 0.77, 0.14, and 0.07 kg . hm^-2-2, respectively. The annual returns of the seven mineral elements were significantly positively correlated with their annual concentrations.