摘要
2012年6月-2013年5月期间,根据温度动态过程,对比研究了生长季节(土壤完全融化期、生长季节前期和生长季节后期)与非生长季节(冻结初期、深冻期和融化期)川西亚高山粗枝云杉(Picea asperata)人工林林窗中心、林缘和林下土壤有机层和矿质土壤层硝态氮和铵态氮含量变化过程。结果表明,在生长季节的3个关键时期土壤硝态氮含量表现为林窗中心高于林缘和林下;而在非生长季节表现为林缘大于林窗中心和林下,且土壤有机层和矿质土壤层表现出相似的规律。除深冻期外,林下土壤铵态氮含量均高于林窗中心和林缘,但林下土壤总矿质氮含量较小。此外,整个研究期间不同关键时期林下土壤总矿质氮均以铵态氮为主,而林窗中心在生长季节以硝态氮为主,在冻融季节以铵态氮为主。可见,高寒森林林窗更新对土壤氮过程的作用受到季节性冻融循环的影响。
A field experiment was carried out from June 2012 to May 2013 to study the dynamics of soil nitrate nitrogen and ammonium nitrogen under gap center, gap edge and under canopy. Samples of soil in organic layer and mineral layer were collected in growing period （completely soil thawing stage, early stage and later stage of growing season） and freeze-thaw period （onset stage of freezing, deeply soil freezing stage and soil thawing stage）. The results showed that higher soil nitrate nitrogen content was detected in gap center com- pared with which in gap edge and under canopy regardless of stages in growing period. In contrast, soil ni- trate nitrogen content was higher in gap edge than that in gap center and under canopy. Soil nitrate nitrogen and ammonium nitrogen contents in both organic layer and mineral layer displayed similar dynamics pattern at different sampled stages. Except for deeply soil freezing stage, the other sampled stages showed higher soil ammonium nitrogen content in under canopy compared with that in gap center and gap edge, although soil to- tal mineral nitrogen content was lower. In addition, soil ammonium nitrogen dominated soil mineral nitrogen in under canopy regardless ofsampled stages, but soil nitrate nitrogen and soil ammonium nitrogen in gap center dominated soil mineral nitrogen in growing period and freeze-thaw period, respectively. The results imply that soil nitrogen process driven by forest gap regeneration was influenced by seasonal freeze-thaw cy- cles in the high-frigid forest ecosystem.
出处
《水土保持学报》
CSCD
北大核心
2013年第6期270-274,共5页
Journal of Soil and Water Conservation
基金
国家自然科学基金项目(31170423
31200474
31270498)
国家"十二五"科技支撑计划(2011BAC09B05)
四川省杰出青年学术与技术带头人培育项目(2012JQ0008
012JQ0059)
中国博士后科学基金(2012T50782)
关键词
亚高山森林
林窗
土壤铵态氮
土壤硝态氮
关键时期
subalpine forest
forest gap
soil ammonium nitrogen
soil nitrate niteogen
critical periods
