饱和持水量条件下不同氮添加对森林土壤氮素净转化的影响
发布时间：2018-11-09 11:53
【摘要】：为了研究在饱和持水量条件下不同氮沉降形态和水平对森林土壤氮素净转化及土壤N_2O排放的影响,选取中亚热带地带性森林红壤为研究对象,采用室内模拟试验方法,设置110%饱和持水量(WHC)的土壤水分,添加不同形态氮[(NH_4)_2SO_4、NaNO_3、NH_4NO_3]和不同含量[0 mg/kg(CK)、20.0 mg/kg(LN)、66.7 mg/kg(HN),以干土计]的氮素,进行为期14 d的室内培养(20℃).结果表明,与CK相比,(NH_4)_2SO_4和NaNO_3处理对土壤净氮矿化和氨化的影响不大,而(NH_4)_2SO_4处理的净硝化量在高氮水平下为负值,说明硝化很弱,但该处理的净氨化量高于其他处理,特别是NaNO_3处理的净氨化量较高,认为很可能存在NO_3~--N异化还原为铵(DNRA).NaNO_3处理能显著提高土壤净硝化量而显著降低w(SON)(SON为土壤可溶性有机氮),NH_4NO_3处理同时降低了土壤w(NH_4~+-N)和w(NO_3~--N),表现为氮固定作用,并且高氮水平的土壤w(MBN)(MBN为微生物量氮)显著高于低氮水平;NaNO_3和NH_4NO_3处理的土壤N_2O排放速率和培养周期内的累积排放量均显著高于CK,并且高氮水平显著高于低氮水平,而(NH_4)_2SO_4处理与CK相当,并且高氮水平下的N_2O累积排放量低于低氮水平.研究显示,在过饱和土壤水分条件下,混合形态氮对土壤氮素净转化格局影响较大,含NO_3~-形态氮明显促进土壤N_2O的排放,尤其是高氮水平.研究结果可为评价全球气候变化下特别是降雨情况下沉降氮形态对土壤氮素转化的影响提供重要参考.
[Abstract]:In order to study the effects of different nitrogen deposition forms and levels on net nitrogen conversion and N2O emission from forest soil under saturated water holding capacity, the forest red soil of middle subtropical zone was selected as the research object, and the indoor simulation test method was adopted. Soil moisture with 110% saturated Water holding capacity (WHC), adding different forms of nitrogen [(NH_4) _ 2SO _ 2SO _ 4 / Nano _ 3] and different contents [0 mg/kg (CK), 20.0 mg/kg (LN),] The nitrogen of mg/kg (HN), was cultured for 14 days (20 鈩，
本文编号：2320337
[Abstract]:In order to study the effects of different nitrogen deposition forms and levels on net nitrogen conversion and N2O emission from forest soil under saturated water holding capacity, the forest red soil of middle subtropical zone was selected as the research object, and the indoor simulation test method was adopted. Soil moisture with 110% saturated Water holding capacity (WHC), adding different forms of nitrogen [(NH_4) _ 2SO _ 2SO _ 4 / Nano _ 3] and different contents [0 mg/kg (CK), 20.0 mg/kg (LN),] The nitrogen of mg/kg (HN), was cultured for 14 days (20 鈩，
本文编号：2320337
本文链接：https://www.wllwen.com/kejilunwen/nykj/2320337.html
