摘要
设计了2种处理(即氮添加,100 kg N.hm-2.a-1;氮磷添加,100 kg N.hm-2.a-1+50 kg P.hm-2.a-1),研究了氮磷添加对亚热带北部常绿阔叶林土壤无机氮和氮素矿化的影响。结果表明,不同处理0～10 cm和10～20 cm土层无机氮(铵态氮+硝态氮)含量年平均值分别为:对照7.27和6.80 mg.kg-1、氮添加13.94和8.92 mg.kg-1、氮磷添加11.20和7.13 mg.kg-1,其中铵态氮分别占90.66%和91.15%、65.78%和72.85%、84.64%和85.08%。不同处理0～10 cm和10～20 cm土层的净氨化、净硝化和净氮矿化速率具有相似的季节性变化规律,即夏季氮素净转化速率最高,冬季氮素净转化速率最低,春季和秋季氮素净转化速率有一定差异,但不显著。研究表明,养分添加使土壤年平均净氮矿化速率下降,氮添加使土壤硝化速率下降,氨化速率上升;而氮磷添加使硝化速率上升,氨化速率下降。养分添加对森林生态系统的氮动态影响效应尚需长期定位观测。
Three treatments （no nutrient addition, CK; N addition, 100 kg N·hm^-2·a^-1; and N＋P addition, 100 kg N·hm^-2·a^-1 ＋ 50 kg P·hm^-2·a^-1） were installed in an evergreen broadleaved forest in northern subtropics to study the effects of nutrient addition on the soil nitrogen dynamics and mineralization in the forest. The annual mean inorganic N concentrations （NH4＋-N ＋ NO3--N） in 0-10 cm and 10-20 cm soil layers for the treatments CK, N addition, and N＋P addition were 7.27 and 6.80 mg·kg^-1, 13.94 and 8.92 mg·kg^-1, and 11.20 and 7.13 mg·kg^-1, respectively, among which, the percentages of NH4＋-N to total inorganic N were 90.66% and 91.15%, 65.78% and 72.85%, and 84.64% and 85.08%, respectively. The net ammonification, nitrification, and N mineralization rates in the 0-10 cm and 10-20 cm soil layers of the three treatments showed the similar seasonal patterns, with the maximum in summer and the minimum in winter. There were no significant differences for the net rates of N transformation in spring and autumn. Nutrient addition （N and N＋P） decreased the annual average net rates of nitrogen mineralization. N addition decreased the net nitrification rate but increased the net ammonification rate, whereas N＋P addition increased the net nitrification rate but decreased the net ammonification rate. Due to the long-term dynamic processes of forest ecosystems in response to nutrient addition, it would be necessary to conduct a long-term observation on the nitrogen dynamics in forest ecosystems under scenario of increasing N deposition.
出处
《生态学杂志》
CAS
CSCD
北大核心
2013年第7期1690-1697,共8页
Chinese Journal of Ecology
基金
国家重点基础研究发展计划项目(2010CB950602)
国家自然科学基金项目(30771719
30471386)资助
关键词
养分添加
森林土壤
亚热带林
氮动态
氮素转化
nutrient addition
forest soil
subtropical forest
nitrogen dynamics
nitrogen trans-formation.
