摘要
以三峡库区马尾松人工林为对象,将土壤筛分为大团聚体(2000~8000μm)、粗砂粒(1000~2000μm)、小团聚体(250~1000μm)和微团聚体(<250μm)4个粒径,研究低、中、高氮添加处理(氮添加量分别为30、60、90 kg N·hm^(-2)·a^(-1))下土壤酸解性有机氮组分和净氮矿化的变化。结果表明:不同处理下,团聚体净硝化速率为0.30~3.42 mg N·kg^(-1),占净氮矿化的80%以上。与对照相比,不同处理4个粒径的总氮含量分别提高24.1%~45.5%、6.4%~34.3%、7.9%~42.4%,净氮矿化速率分别提高1.3~7.2、1.4~6.6、1.8~12.9倍,而速效磷含量分别降低9.3%~36.9%、12.2%~56.7%、19.2%~61.9%。可酸解性有机氮组分、有机质含量以及净氨化、净硝化和净氮矿化速率均随着团聚体粒径的减小而增加,但速效磷含量变化呈相反的趋势。酸解性有机氮组分含量大小为:酸解氨基酸态氮>酸解铵态氮>酸解未知态氮>酸解氨基糖态氮。总氮是提高酸解性有机氮组分含量的主导因子。多元逐步回归显示,酸解氨基酸态氮和酸解氨基糖态氮含量影响了净氨化速率;酸解氨基糖态氮、酸解氨基酸态氮和酸解铵态氮含量共同影响了净硝化、净氮矿化速率以及净氮矿化累积量。综上,团聚体的物理结构影响了土壤氮矿化,氮添加提高了土壤生物可利用性及易矿化态酸解性有机氮的含量,但大量氮添加导致土壤有机质和速效磷含量下降。
We sieved soils from a Pinus massoniana plantation in the Three Gorges Reservoir area into four aggregate sizes,including aggregates of 2000-8000μm(large macroaggregates),1000-2000μm(coarse aggregates),250-1000μm(small macroaggregates),and<250μm(microaggregates).We analyzed the differences in the acidolyzable organic N components and net N mineralization of the aggregates under different N addition levels(30,60,and 90 kg N·hm^(-2)·a^(-1),representing by N30,N60 and N90,respectively).The results showed that net nitrification rate of the aggregates ranged from 0.30-3.42 mg N·kg^(-1)and accounted for more than 80%of net nitrogen mineralization.Compared with the control,addition of 30,60,and 90 kg N·hm^(-2)·a^(-1)increased total N by 24.1%-45.5%,6.4%-34.3%,and 7.9%-42.4%in the large aggregates,coarse aggregate,small macroaggregates,and microaggregates,increased net N mineralization rate by 1.3-7.2,1.4-6.6,and 1.8-12.9 times,but decreased the contents of available phosphorus by 9.3%-36.9%,12.2%-56.7%,and 19.2%-61.9%,respectively.The contents of total acidolyzable N,soil organic matter,and rates of net ammonification,net nitrification,and net N mineralization increased as the aggregate size decreased,while available phosphorus contents showed an opposite trend.The levels of acid-hydrolyzable N components were ranked as acidolyzable amino acid N>acidolyzable ammonia N>acidolyzable unknown N>acidolyzable amino sugar N.Total N was the dominant contributor to the increases in acid-hydrolyzable N components.Results of stepwise multiple regression analyses showed that acidoly-zable amino acid N and acidolyzable amino sugar N were predictors of net ammonification rate.Acidolyzable amino sugar N,acidolyzable amino acid N,and acidolyzable ammonia N were predictors of net nitrification,net nitrogen mineralization rate,and net nitrogen mineralization accumulation.The physical structure of aggregates was associa-ted with soil net N mineralization.Addition of N increased the contents and bioavailability of acidolyzable org
作者
陈天
程瑞梅
沈雅飞
肖文发
王丽君
孙鹏飞
张萌
李璟
CHEN Tian;CHENG Ruimei;SHEN Yafei;XIAO Wenfa;WANG Lijun;SUN Pengfei;ZHANG Meng;LI Jing(Key Laboratory of Forest Ecology and Environment,National Forestry and Grassland Administration,Research Institute of Forest Ecology,Environment and Protection,Chinese Academy of Forestry,Beijing 100091,China;Co-Innovation Center for Sustainable Forestry in Southern China,Nanjing Forestry University,Nanjing 210037,China)
出处
《应用生态学报》
CAS
CSCD
北大核心
2023年第10期2601-2609,共9页
Chinese Journal of Applied Ecology
基金
中国林业科学研究院基本科研业务费专项(CAFYBB2021ZE003)资助。
关键词
氮添加
团聚体
矿化
有机氮
nitrogen addition
aggregate
mineralization
organic nitrogen
