亚热带不同林分土壤矿质氮库及氮矿化速率的季节动态

发布时间：2018-12-17 00:28

【摘要】：以亚热带地区天然林、格氏栲人工林和杉木人工林为对象,采取PVC管原位培养连续取样法,对不同林分土壤净氨化速率、净硝化速率及净氮矿化速率进行为期一年(2014年9月—2015年8月)的研究,分析林分类型和季节动态对土壤矿质氮库和净氮矿化速率的影响.结果表明:硝态氮是该地区土壤矿质氮库的主要存在形式,天然林和杉木人工林土壤硝态氮含量分别占总土壤矿质氮库的55.1%~87.5%和56.1%~79.1%,林分间土壤铵态氮含量差异不显著,硝态氮含量差异显著,其中格氏栲人工林土壤硝态氮含量显著低于天然林和杉木人工林.土壤硝态氮库和矿质氮库在不同月份间差异显著,在植物非生长季节(10月至次年2月)较大,在植物生长季节(3—9月)较小.各林分全年土壤净硝化速率均较低,净氨化速率是净氮矿化速率的主要存在形式,林分类型对土壤净氨化速率有显著影响,其中杉木人工林显著低于天然林和格氏栲人工林.月份对土壤净氨化速率有显著影响,各林分土壤净氨化速率变化规律不一致,但均在11月和2月达到一年中的最低值.重复测量方差分析显示,林分类型和季节动态对土壤矿质氮库及氮矿化速率均有显著影响.温度和水分是影响土壤矿质库及氮矿化速率的重要因素,凋落物对土壤氮矿化速率的影响主要是通过质量控制而非数量控制.
[Abstract]:The natural forest, Castanopsis kawakamii plantation and Chinese fir plantation in subtropical region were studied. The soil net ammoniation rate of different stands was studied by continuous sampling method of PVC tube culture in situ. The net nitrification rate and net nitrogen mineralization rate were studied for one year (September 2014 to August 2015) to analyze the effects of stand types and seasonal dynamics on soil mineral nitrogen pool and net nitrogen mineralization rate. The results showed that nitrate nitrogen was the main form of mineral nitrogen pool in this area, and the nitrate content of natural forest and Chinese fir plantation accounted for 87.5% and 56.1% of the total mineral nitrogen pool, respectively, and 56.1% and 79.1% of the total mineral nitrogen pool in the natural forest and Chinese fir plantation, respectively. There was no significant difference in soil ammonium nitrogen content among stands, but there was significant difference in nitrate nitrogen content, especially in Castanopsis kawakamii plantation soil nitrate nitrogen content was significantly lower than that in natural forest and Chinese fir plantation. Soil nitrate pool and mineral nitrogen pool were significantly different in different months, which were larger in non-growth season (from October to February) and smaller in plant growing season (March to September). The net nitrification rate of all stands was low, and the net ammoniation rate was the main form of net nitrogen mineralization rate. The type of stand had significant influence on the net nitrification rate of soil, and the Chinese fir plantation was significantly lower than the natural forest and Castanopsis kawakamii plantation. The change of net ammoniation rate of different stands was not consistent, but reached the lowest value in November and February. Repeated measurement variance analysis showed that stand types and seasonal dynamics had significant effects on soil mineral nitrogen pool and nitrogen mineralization rate. Temperature and water are the important factors that affect the mineralization rate of soil nitrogen and the effect of litter on soil nitrogen mineralization rate is mainly through quality control rather than quantity control.
【作者单位】：湿润亚热带山地生态国家重点实验室培育基地;福建师范大学地理科学学院;福建农林大学林学院;
【基金】：国家自然科学基金项目(41371269) 国家重点基础研究发展计划项目(2014CB954003)资助~~
【分类号】：S714

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