红壤区3种典型植被恢复模式凋落物动态及碳氮归还特征

Dynamic of litter and characteristics of carbon & nitrogen return in three typical vegetation restoration patterns in red soil

对红壤区侵蚀地3种典型植被恢复模式——阔叶林、封育林和木荷×马尾松混交林的凋落物量及其组分进行了为期24个月的研究,分析了凋落物各组分月动态特征,以及凋落物各组分碳、氮元素归还量和季度动态特征。研究结果表明,阔叶林、封育林和木荷×马尾松混交林的年均凋落物量表现出明显的差异,总体上表现为叶>枝>杂>果>花,叶凋落量占总凋落物量的比率均较高,分别为83.10%、70.91%和73.66%。凋落物的月动态变化都表现出受凋落叶主导的规律。阔叶林、封育林和混交林凋落物碳元素归还量出现在第4季度,混交林在第2季度,阔叶林最大氮元素归还量出现在第4季度,封育林和混交林在第2季度。木荷×马尾松混交林年凋落量最大,碳、氮元素归还量也最大,更有利于养分归还和土壤质量恢复。

The amount of litter and its components were studied for 24 months in the three vegetation restoration patterns（ broad-leaved forest,enclosed forest and Schima superba-Pinus massoniana mixed forest） in eroded red soil. Different litter components and their monthly dynamic characteristics were determined,as well as the amount of carbon and nitrogen return and seasonal dynamics in litter components. The results showed that： The amount of litter in each component showed significant difference,but in general,the order was leaf 〉 Branch 〉 miscellaneous 〉 fruit 〉 flower. The ratio of leaf litter to total litter was higher,with 83. 10%,70. 91% and 73. 66% separately. The monthly dynamic changes of litter by leaf litter showed dominant regularity. There were two peaks in broad-leaved forest and enclosed forest,appearing in 3- 4 months and10- 11 months respectly. Schima superba- Pinus massoniana mixed forest has three peaks,in 3- 4 months,august and November separately. The maximum carbon return in broad-leaved forest and enclosed forests appeared both in the fourth season of the year,and mixed forest was in the second season. The maximum nitrogen return in broad-leaved forest was in the fourth season,and enclosed forests and mixed forest was in the second season. Our results indicate that Schima superba-Pinus massoniana mixed forest had the highest annual litter production,carbon and nitrogen return,which benefits nutrient return and soil recover.