雪被斑块对川西亚高山两个森林群落冬季土壤氮转化的影响  

Effects of snow pack on wintertime soil nitrogen transformation in two subalpine forests of western Sichuan

作　　者：殷睿[1] 徐振锋[1] 吴福忠[1] 杨万勤[1] 李志萍[1] 熊莉[1] 肖洒[1] 王滨[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：《生态学报》2014年第8期2061-2067,共7页Acta Ecologica Sinica

摘　　要：为了解气候变暖情景下雪况变化对高寒森林冬季土壤氮转化的影响,测定了川西亚高山冷杉(Abies faxoniana)+红桦(Betula albo-sinensis)混交林(MF)和冷杉次生林(SF)三类雪被斑块(浅雪被、中厚度雪被和厚雪被)内冬季土壤氮矿化特征。结果表明:经过一个冬季(2011-2012),两个森林群落土壤净氮氨化量都为负值,净氮硝化量都为正值,且净氮硝化量显著高于净氮氨化量;冬季土壤氮氨化、硝化、矿化和固持量都是中度雪被厚度最高,但各雪被斑块之间都未达到显著水平。各雪被斑块下,冷杉次生林土壤氮矿化参数都显著高于针阔混交林,但雪被斑块和林型交互作用对冬季土壤氮矿化无显著影响。这表明,该区冬季土壤氮矿化以硝化过程为主,硝化和氨化过程可能受不同微生物群落调控;短时期内,未来气候变化所导致的雪被减少对该区森林冬季土壤氮转化影响可能不明显。A consensus in global ecology is that climate change is profoundly altering the process of terrestrial ecosystem. In particular, more and more attentions have been focused on the effects of snow pack on soil process in cold biomes recently, since climate change characterized by winter warming and extreme is changing the pattern of seasonal snow cover and freeze- thaw cycles in the high-latitude and high-altitute regions. As yet, the results concerning the effects of seasonal cover and freeze-thaw cycles on soil process remain uncertainty, and little information has been available on the effects of snow pack on soil nitrogen tansformation in the subalpine forest of western Sichuan, China. In order to deeply understand the process of soil nitrogen transformation in the subalpine forest of western Sichuan under climate change scenarios, therefore, wintertime net nitrogen mineralization, net nitrogen ammonification, net nitrogen nitrification and microbial nitrogen immobilization in soils under three depths of snowpacks （ deep snowpack, middle snowpack and shallow snowpack） were measured in two subalpine forests of western Sichuan, which locates at the upper reaches of Yangtze River and the eastern Qinghai-Tibet Plateau. The top of soil columns sampled from Abies fitxolLiana ＋ Betula albo-sinensis mixed forest and secondary fir forest were closed, and then in-situ incubated in the forest floor under deep snowpack, middle snowpack and shallow snowpack of the corresponding forest from November 2011 to April 2012, respectively. The results indicated that wintertime soil netnitrogen ammonification ranged from -2.37mg/kg to -2.22 mg/kg under different snowpacks in the mixed forest, and from -7.73 mg/kg to -7.10 mg/kg under different snowpacks in the secondary fir forest. Wintertime soil net nitrogen nitrification varied from 71.98 mg/kg to 82.69 mg/kg under different snowpacks in the mixed forest, and from 101.56 mg/kg to 124.89 mg/kg under different snowpaeks in the secondary fir forest. Net nitrogen nitrification

关 键 词：季节性雪被 亚高山森林 氮矿化 氮硝化 氮氨化 氮固持 

分 类 号：S714.2[农业科学—林学]