不同植被覆盖下植物残体分解特性

以黄土丘陵沟壑区子午岭次生林区为研究区域,研究了不同植被覆盖下植物残体的分解特性。结果表明:不同植被类型覆盖下,植物残体腐解速率为苜蓿>玉米>大油芒>辽东栎>沙棘,添加氮素比不加氮素的植物残体腐解速度快。根据腐解残留量的变化可将腐解过程分为4个阶段:快速分解阶段(0~1个月)、分解停滞阶段(2~7个月)、缓慢分解阶段(8~12个月)和趋于稳定阶段(13~15个月)。根据Olson指数衰减模型对植物残体腐解速率和腐解时间进行拟合,发现玉米、苜蓿、大油芒、辽东栎、沙棘分解95%所需的时间(T0.95)分别为43.73、23.35、52.56、108.1和161.1个月,且检验结果均达到显著相关水平。

Residue decomposition in soils under different vegetation types

Based on the secondary forest at Ziwuling in typical hilly-gully regions on the Loess Plateau,the decay of plant residues in soils under different vegetation types is studied.The results show that the decaying rate is: Alfalfa>Corn>S.sibiricus>Q.liaotungensis>H.rhamnoides under different vegetation types. The decaying rate of plant residues adding N was higher than that without N.According to changes of decaying remainders,the decaying process can be divided into 4 stages: the fast decomposition stage,the stagnant decomposition stage,the slow decomposition stage,the stage of trending to be stable.According to the model simulation by Olson's exponential function,corn might take 43.73 months to reach its 95% of decay(T0.95),compared with 23.35 months for Alfalfa,52.56 months for S.sibiricus,108.1 months for Q.liaotungensis and 161.1 months for H.rhamnoides.And there is significant relationship between the decaying rate of plant remainder and the decaying time.