引用本文:马芬,马红亮,邱泓,高人,尹云锋,彭园珍,等.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[J].环境科学研究,2017,30(4):570-578.
MA Fen,MA Hongliang,QIU Hong,GAO Ren,YIN Yunfeng,PENG Yuanzhen,et al.Effects of Different Nitrogen Addition on Net Nitrogen Transformation in Forest Soil under Saturation Water Holding Capacity Condition[J].Reserrch of Environmental Science,2017,30(4):570-578.]
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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
马 芬1,2, 马红亮1,2, 邱 泓1,2, 高 人1,2, 尹云锋1,2, 彭园珍1,2
1.福建师范大学地理科学学院, 福建 福州 350007 ;2.福建师范大学, 湿润亚热带山地生态国家重点实验室培育基地, 福建 福州 350007
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N2O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〔(NH4)2SO4、NaNO3、NH4NO3〕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,(NH4)2SO4和NaNO3处理对土壤净氮矿化和氨化的影响不大,而(NH4)2SO4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NaNO3处理的净氨化量较高,认为很可能存在NO3--N异化还原为铵(DNRA).NaNO3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),NH4NO3处理同时降低了土壤w(NH4+-N)和w(NO3--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;NaNO3和NH4NO3处理的土壤N2O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(NH4)2SO4处理与CK相当,并且高氮水平下的N2O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NO3-形态氮明显促进土壤N2O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.
关键词:  氮素水平  氮素形态  氮矿化  氧化亚氮  饱和土壤水分
DOI:
分类号:
基金项目:国家自然科学基金项目(41271282,31170578);教育部创新团队项目(IRT0960)
Effects of Different Nitrogen Addition on Net Nitrogen Transformation in Forest Soil under Saturation Water Holding Capacity Condition
MA Fen1,2, MA Hongliang1,2, QIU Hong1,2, GAO Ren1,2, YIN Yunfeng1,2, PENG Yuanzhen1,2
1.College of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China ;2.Cultivation Base of State Key Laboratory of Humid Subtropical Mountain Ecology, Fujian Normal University, Fuzhou 350007, China
Abstract:
Abstract:Soil moisture conditions regulate nitrogen transformation and the effects of nitrogen deposition.However,the effect of nitrogen deposition on nitrogen transformation is not very clear under saturation water holding capacity condition.Therefore,in order to investigate the effects of different nitrogen deposition on soil net nitrogen transformation and N2O emission under saturation moisture capacity condition,using zonal red soil collected from Wuyi Mountain in mid-subtropical forest,a 14-day simulative experiment in the laboratory was carried out under 110% water holding capacity condition with different nitrogen forms((NH4)2SO4,NaNO3 and NH4NO3)and levels(0(CK),20.0(LN)and 66.7(HN)mg/kg).The results showed that(NH4)2SO4 and NaNO3 treatments had little effect on soil net nitrogen mineralization compared with CK.The net nitrification was negative in(NH4)2SO4 treatment at the high nitrogen level,which illustrated that nitrification was quite weak,while the net ammonification was higher than other treatments especially in NaNO3 treatment.This phenomenon was probably due to the occurrence of dissimilar reduction of nitrate to ammonium(DNRA).The net nitrification was increased significantly,and the soil soluble organic nitrogen(SON)was reduced dramatically in the NaNO3 treatment.The soil ammonium and nitrate nitrogen were reduced simultaneously in the NH4NO3 treatment,demonstrating the immobilization of N,and a higher soil microbial biomass nitrogen(MBN)was observed at high nitrogen level than at low nitrogen level.The rate and cumulative amount of soil N2O emission in both the NaNO3 and NH4NO3 treatments were obviously higher than CK,and these effects were much greater at high nitrogen level than at low nitrogen level.The soil N2O emission in the(NH4)2SO4 treatment was almost equal to that of CK,and the cumulative amount of soil N2O emission was lower at high nitrogen level compared with that of low nitrogen level.Taken together,we concluded that,under saturation water holding capacity condition,mixed nitrogen form may have greater effect on soil nitrogen transformation pattern,and nitrogen in form of NO3- significantly promoted the soil N2O emission especially at high nitrogen level.These results provide useful information when assessing the effect of different deposited nitrogen forms on soil nitrogen transformation under precipitation circumstance.
Key words:  nitrogen level  nitrogen form  nitrogen mineralization  nitrous oxide  saturated soil moisture