摘要
研究在我国亚热带红壤地区采集林地、竹林、茶园和旱地农田4种利用方式的土壤样品,测定了氮素净矿化和净硝化以及N2O排放速率,定量了氨氧化细菌(AOB)和氨氧化古菌(AOA),以期阐明土地利用方式对红壤氮素矿化和硝化作用的影响。结果表明,不同利用方式红壤AOA基因拷贝数在6.20×106到6.58×106copies g-1土;AOB基因拷贝数在4.18×106到7.41×106copies g-1土,AOA和AOB丰度的最大值均出现在旱地红壤。旱地红壤0~7天和0~14天的氮素净矿化速率分别为3.46和1.62 mg kg-1,均显著高于其他利用方式。氮素净矿化速率与土壤pH值呈显著的正相关关系(P<0.05),与C/N呈显著的负相关关系(P<0.05),说明土壤pH和C/N是影响不同利用方式红壤氮素净矿化速率的主要因子。旱地红壤0~7天和0~14天的净硝化速率分别为5.33和3.06 mg kg-1,也均显著高于其他利用方式。净硝化速率与铵态氮(NH4+-N)含量(P<0.01)、pH(P<0.05)和AOB(P<0.01)均呈显著的正相关关系,表明土壤p H和可利用NH4+-N含量是影响红壤净硝化速率的重要因素,高土壤pH和NH4+-N含量有利于AOB的生长和活性,从而明显增加净硝化速率。然而,不同利用方式红壤的N2O排放速率却没有显著的差异,说明利用方式似乎不影响土壤N2O排放,这与净硝化速率变化规律相矛盾。可能的原因是,除了硝化作用外,好氧培养条件下还存在其他重要的N2O产生途径,将来的研究中需要关注不同利用方式红壤N2O产生途径,以阐明红壤N2O排放机制。
The net nitrogen(N)mineralization and nitrificationrates,nitrous oxide(N2O)emission and abundances of ammonia-oxidizing archaea(AOA)and bacteria(AOB)were determined in the soils under four land use types,i.e.forest(F),bamboo(B),tea plantation(TP)and upland(U),in orderto identify the effects of land use on N mineralization and nitrification of red soil in subtropical region of China.The result showed that the soil pH value was the highest and ratio of C to N(C/N)was the lowest under U among the 4 land use types.The numbers of AOA ranged from 6.20×106to 6.58×106copies-1g soil and those of AOB varied from 4.18×106to 7.41×106copies g-1soil.The soil AOA and AOB were the highestunder U among the 4 land use types.The net N mineralization rates(3.46 and 1.62 mg kg-1,respectively)in U soil at 0-7 days and 0-14 days were significantly higher than those in the soilsunder the other land use types mainly due to higher soil pH value and lower C/N ratio.The net N nitrification rates were 5.33 and 3.06 mg kg-1soil at 0-7 days and 0-14 days,respectively,which was significantly higher under U than those under the other land use types.Net nitrification rateswere positively correlated with ammonium N(NH4+-N)(P<0.01),AOB(P<0.01),and p H(P<0.05).These results indicated that higherpHvalue and content of available NH4+-N stimulated the abundance of AOB and were responsible for the higher net nitrification rate in U soil.However,there was no significant difference in the average N2O emission rate among the different land use types,which indicated that the land use did not affect the N2O emissions.This was contradict with the results of net nitrification rate under U land use.One reason was probably that there were some other production pathways of N2O in soils besides nitrification process.In the future,the effects of land use types on the production pathways of N2O should be studied,in order to clarify the mechanisms of N2O emissions in red soil.
作者
Nanang Zulkarnaen
程谊
张金波
ZULKARNAEN Nanang;CHENG Yi;ZHANG Jin-bo(School of Geography,Nanjing Normal University,Nanjing 210023,China;State Key Laboratory Cultivation Base of Geographical Environment Evolution(Jiangsu Province),Nanjing 210023,China;Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application,Nanjing 210023,China;Key Laboratory of Virtual Geographical Environment(VGE),Ministry of Education,Nanjing Normal University,Nanjing 210023,China)
出处
《土壤通报》
CAS
CSCD
北大核心
2019年第5期1210-1217,共8页
Chinese Journal of Soil Science
基金
国家重点研发计划（2017YFD020101）资助
关键词
氨氧化古菌
氨氧化细菌
净矿化速率
净硝化速率
N2O
土地利用
Ammonia-oxidizing archaea
Ammonia-oxidizing bacteria
Net nitrogen mineralization rate
Net nitrification rate
Nitrous oxide
Land use
