川西亚高山不同海拔3种森林群落土壤氮转化的季节动态  

Seasonal Dynamics of Soil Nitrogen Transformation along Subalpine Elevational Gradient of Western Sichuan

作　　者：殷睿[1] 徐振锋[1] 吴福忠[1] 杨万勤[1] 熊莉[1] 肖洒[1] 马志良[1] 李志萍[1] 

机构地区：[1]四川农业大学生态林业研究所林业生态工程重点实验室,成都611130

出　　处：《林业科学》2014年第7期1-7,共7页Scientia Silvae Sinicae

基　　金：国家自然科学基金项目(31170423;31200474;31270498;31000213);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;2012JQ0059);中国博士后科学基金(2012T50782)

摘　　要：采用封顶埋管原位培养法研究川西亚高山不同海拔3种森林群落(岷江冷杉原始林A、针阔混交林B和珉江冷杉次生林C)土壤氮转化的季节动态特征。结果表明:3种森林群落的土壤净氨化速率、净硝化速率、净氮矿化速率和净氮固持速率都存在明显的季节动态;在非生长季,3种森林群落的净硝化速率、净氮矿化速率和净氮固持速率都为正值,而净氨化速率极低且为负值;各时期土壤氮矿化过程以土壤硝化作用为主,且土壤净硝化速率与净氮矿化速率季节动态趋势一致;土壤净氮矿化速率在生长季初期最低,在生长季中期达全年最高峰;不同海拔之间土壤净氨化速率差异显著(P<0.05);B海拔的土壤净硝化速率和净氮矿化速率低于其他2个海拔,但差异未达到显著水平;非生长季氮素固持作用最强。The seasonal dynamics of soil nitrogen transformation in the three forest ecosystems （Primary fir forest, Fir- birch mixed forest and Secondary fir forest） along a suhalpine elevational gradient of western Sichuan were investigated using a method of in situ top-closed incubation. The resuh showed that there were obvious seasonal variations in the rates of soil net nitrogen ammonification, nitrification, mineralization and fixation. The rates of net nitrogen nitrification, mineralization and fixation were higher in the non-growing season than in growing season, hut net ammonification rate was very low and negative. Soil net nitrogen mineralization rate was the lowest in the early growing season, but the highest in the middle growing season. S0il net ammonification rates varied significantly with elevations （P 〈 0.05）. During the experimental period, soil nitrification contributed mostly to soil nitrogen mineralization and had a similar seasonality with soil nitrogen mineralization. The rate of soil net nitrogen mineralization at B was relatively lower than those of other two elevations, but there was no significant difference between them. Soil net nitrogen fixation rate was relatively higher in the non-growing season than in the growing season.

关 键 词：亚高山森林 海拔 土壤氮转化 氨化 硝化 氮矿化 氮固持 

分 类 号：S714.5[农业科学—林学]