滇中高原云南松林枯落物凋落动态及化学计量特征研究

Litter Fall Production Dynamics and Its Stoichiometric Characteristics of Pinus yunnanensis Forest in the Central Yunnan Plateau

探究滇中高原磨盘山云南松天然林枯落物凋落动态及各组分化学计量特征,为云南松林地的经营管理以及森林生态系统养分再分配提供理论依据。以磨盘山云南松林为对象,采用野外枯落物收集器法对云南松林枯落物凋落动态进行研究,并通过室内试验对云南松林枯落物化学计量特征进行了分析。结果表明:1)云南松枯落物凋落动态存在明显的月变化,月凋落量变化曲线呈双峰型,凋落量最大值出现在5月,最小值出现在9月,叶的凋落动态与总枯落物凋落动态基本一致,而花、果枯落物具有明显的季节性;2)云南松枯落物各组分之间TC、TN、TP含量及C/N、C/P、N/P均存在显著差异(P<0.05),各组分的平均TC、TN、TP含量变动范围分别为433.37~473.74、3.1~6.77、1.26~1.76 g·kg^(-1),云南松枯落物的平均C/N值高于全球枯落物平均值,而C/P和N/P值则低于全球枯落物;3)云南松林枯落物年凋落总量为12472.36 kg·hm^(-2),叶凋落量占比最大,占到年凋落总量的58.25%;云南松枯落物TC、TN、TP年归还量分别为5672.40、66.24、17.52 kg·hm^(-2),叶枯落物的养分年归还量均显著(P<0.05)高于其他各组分。

Nutrient cycling is one of the most essential functions in ecosystem,and litter fall plays an important role in nutrient cycling in forests ecosystem.The main objectives of this study were to characterize the monthly litter production dynamics and the stoichiometric characteristics of various components of litter fall in Pinus yunnanensis forests occurring in the Mopan Mountain in the central Yunnan Plateau to provide a theoretical basis for the management of forest land and help to understand the redistribution of nutrients in the forest ecosystem.The P.yunnanensis forest was selected as the research object.Based on the community investigation,the litter falls were collected by litter trap.The litter fall production and C,N,P contents were determined and analyzed in laboratory.The results showed that 1)the monthly litter production dynamics of P.yunnanensis showed a bimodal pattern,the maximum litter production was in May,and the minimum was in September.The leaf litter production dynamics showed a similar trend to that of total litter production dynamics.The flowers and fruits litters had a significant seasonality.2)There were significant differences in the TC,TN,TP and C/N,C/P,N/P among the various components of P.yunnanensis forest litter(P<0.05).The range of TC,TN and TP contents in P.yunnanensis forest litter were 433.37-473.74,3.1-6.77 and 1.26-1.76 g·kg^(-1),respectively.The average litter C/N ratio was higher than the global average,while the C/P and N/P values were lower than the global average.3)The annual litter fall production of P.yunnanensis forest was 12472.36 kg·hm^(-2)·a^(-1),with leaf litter contributed an average of 58.25%to the total annual litter production.The annual TC,TN and TP retuned by litter fall in P.yunnanensis forest were 5672.40,66.24 and 17.52 kg·hm^(-2)·a^(-1),respectively.The annual nutrients returned by leaf litter was significant(P<0.05)the highest among the various components of P.yunnanensis forest litter.