西南地区不同林型凋落物-土壤氮、磷含量分布特征

Distribution Characteristics of Litter-Soil N and P Contents of Different Forest Types in the South-West of China

【目的】为了解我国西南地区不同森林类型凋落物和土壤的氮、磷养分状况。【方法】以重庆四面山、缙云山和云南哀牢山、西双版纳6种不同类型森林群落为研究对象,探究其森林凋落物、土壤有机层和矿质层氮、磷含量及计量比的特征。【结果】西南地区6种森林凋落物氮含量变化范围为2.81~6.52 g/kg,磷含量变化范围为1.09~1.54 g/kg;表现为常绿阔叶林>针叶林,纯林>混交林的分布规律;在各林型中,中山湿性常绿阔叶林中凋落物氮磷含量为最丰富,而针叶林最贫瘠;6种森林土壤氮含量变化范围为0.87~6.57 g/kg,磷含量变化范围为0.13~1.09 g/kg;各林型土壤氮磷含量呈现随土壤深度增加而降低的趋势;其中,中山湿性常绿阔叶林土壤氮含量最高,西双版纳季节雨林的土壤氮磷含量最低;相关性分析表明土壤磷含量与凋落物氮含量和氮磷比呈显著正相关。【结论】西南地区不同森林类型之间土壤氮、磷含量差异性显著,其中中山湿性常绿阔叶林养分含量最为丰富,并与地表凋落物养分基质显著相关。研究结果可为了解该区域森林生态系统的养分循环过程提供科学数据。

【Objective】To understand the nitrogen and phosphorus nutrient status of litter and soil in different forest types in the South-west of China.【Method】Taking 6 different types of forest communities in Simian Mountain,Jinyun Mountain in Chongqing,Ailao Mountain in Yunnan and Xishuangbanna as the research regions,the nitrogen,phosphorus content and N/P ratio of forest litter,soil organic layer and mineral layer are measured.【Result】The litter nitrogen content of six forests ranges from 2.81-6.52 g/kg,and the phosphorus content ranges from 1.09-1.54 g/kg,exhibiting evergreen broad-leaved forest>coniferous forest,pure forest>mixed forest Regularity.Among various forest types,Zhongshan moist ever-green broad-leaved forest has the most highest nitrogen and phosphorus contents in litter,while coniferous forest has the least;the soil nitrogen content of the six forests varies from 0.87-6.57 g/kg,and the phosphorus content varies from 0.13-1.09 g/kg;the soil nitrogen and phosphorus content of each forest type shows a trend of decreasing with the increase of soil depth;the Zhongshan moist evergreen broadleaved forest has the highest soil nitrogen content,and the Xishuangbanna seasonal rain forest has the lowest soil nitrogen and phosphorus content.There was a significant positive correlation between soil phosphorus content and litter nitrogen content and nitrogen to phosphorus ratio.【Conclusion】There are significant differences in soil nitrogen and phosphorus content between different forest types in southwestern China.The nutrient content of Zhongshan moist evergreen broad-leaved forest is the most abundant,and it is significantly related to the litter nutrient substrate.The results of the study is would help to deeply understand the nutrients cycling processes in the forests ecosystem in Western China.