摘要
拟通过土壤辐照灭菌的方法,研究土壤微生物对硝态氮和铵态氮在土壤中的相互转化、固持及损失的影响,为提高作物氮肥利用率提供理论依据。采用土壤纯培养的方法,通过外源添加^(15)N标记铵态氮肥[(15NH4)2SO4]和硝态氮肥(Na15NO3),结合γ辐照灭菌的方法,培养30 d后,测定分析了灭菌和未灭菌土壤中总的、来自于肥料的和来自于土壤的铵态氮和硝态氮含量,并定量评价了肥料氮在土壤中的残留、固持和损失情况。结果表明:灭菌显著抑制铵态氮向硝态氮的转化,激发土壤铵态氮的释放,对铵态氮在土壤中的残留、固持和损失没有显著影响;灭菌对土壤硝态氮转化为铵态氮的过程没有影响,降低了硝态氮在土壤中的残留和固持,增加了硝态氮的损失;与外源添加硝态氮相比,外源添加铵态氮促进了土壤自身无机氮的释放,外源添加的铵态氮在土壤中残留低、固持高、损失高。因此,总体来看,灭菌有利于土壤铵态氮的积累,却降低土壤硝态氮的积累。虽然外源铵态氮较外源硝态氮更能激发土壤无机态氮的释放,并更易被土壤固持,但是铵态氮肥较硝态氮肥在土壤中残留少、损失多。
In order to provide a theoretical basis for improving crop nitrogen(N)use efficiency,the effect of soil microorganisms on the behaviors of ammonium and nitrate in soil was studied through the method of soil irradiation sterilization.Two factors were involved in this study,including different soil treatments(sterilization and non-sterilization)and different N forms(15N labeled ammonium and 15N labeled nitrate).After cultivated in a controlled environment for 30 days,the contents of total ammonium and nitrate in soil along with the contents of ammonium and nitrate derived from fertilizers and soil were determined in sterilized and unsterilized soil.The N residue,fixation and loss of ammonium and nitrate fertilizers were also evaluated.The results showed that soil sterilization inhibited the transformation of ammonium to nitrate,stimulated the release of soil ammonium,and had no significant effects on the soil residual,soil fixation and loss of ammonium fertilizer.Soil sterilization had no effect on the conversion of nitrate into ammonium,but reduced the soil fixation of nitrate fertilizer and caused an increase loss of nitrate.The addition of ammonium fertilizer promoted the mineralization of soil organic N compared with nitrate fertilizer.The ammonium fertilizer had higher fixation and higher loss than nitrate.Overall,Soil sterilization was beneficial to the accumulation of ammonium in the soil,but reduced the accumulation of nitrate.Although the application of ammonium could stimulate the release of soil mineral N and more ammonium N was fixed in soil,the loss of ammonium fertilizer was higher compared with nitrate fertilizer.
作者
张昊青
赵学强
喻敏
沈仁芳
ZHANG Hao-qing;ZHAO Xue-qiang;YU Min;SHEN Ren-fang(International Research Center for Membrane Biology and Environment,Foshan University,Foshan Guangdong 528000;State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences,Nanjing Jiangsu 210008;University of Chinese Academy of Sciences,Beijing 100049)
出处
《中国土壤与肥料》
CAS
CSCD
北大核心
2020年第5期175-182,共8页
Soil and Fertilizer Sciences in China
基金
中国科学院战略性先导科技专项B类(XDB15030202,XDB15030302)。
关键词
土壤灭菌
硝化作用
氮损失
氮固持
氮矿化
soil sterilization
nitrification
nitrogen loss
nitrogen fixation
nitrogen mineralization
