Role of Carbon Substrates Added in the Transformation of Surplus Nitrate to Organic Nitrogen in a Calcareous Soil  

作　　者：QIU Shao-Jun JU Xiao-Tang J.INGWERSEN GUO Zi-De C.F.STANGE R.BISHARAT T.STRECK P.CHRISTIE ZHANG Fu-Suo 

机构地区：[1]College of Agricultural Resources and Environmental Sciences,China Agricultural University [2]Ministry of Agriculture Key Laboratory of Plant Nutrition and Fertilizer,Institute of Agricultural Resources and Regional Planning,Chinese Academy of Agricultural Sciences [3]Institute of Soil Science and Land Evaluation,University of Hohenheim [4]Federal Institute for Geosciences and Natural Resources [5]Agri-Environment Branch,Agri-Food and Biosciences Institute

出　　处：《Pedosphere》2013年第2期205-212,共8页土壤圈（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(NSFC)(Nos.31172033 and 41101277);the National Science Basic Research Program of China(No.2007CB109308);the Foundation of the Chinese Ministry of Education for Ph.D.Work(No.20100008110004);the German Research Foundation (DFG)(No.IRTG 1070);the Innovation Group Grant of the National Natural Science Foundation of China(No.31121062)

摘　　要：Excessive amounts of nitrate have accumulated in many soils on the North China Plain due to the large amounts of chemical N fertilizers or manures used in combination with low carbon inputs. We investigated the potential of different carbon substrates added to transform soil nitrate into soil organic N （SON）. A 56-d laboratory incubation experiment using the 15N tracer （K15NO3） technique was carried out to elucidate the proportion of SON derived from accumulated soil nitrate following amendment with glucose or maize straw at controlled soil temperature and moisture. The dynamics and isotopic abundance of mineral N （NO3 and NH4＋） and SON and greenhouse gas （N20 and CO2） emissions during the incubation were investigated. Although carbon amendments markedly stimulated transformation of nitrate to newly formed SON, this was only a substitution effect of the newly formed SON with native SON because SON at the end of the incubation period was not significantly different （P 〉 0.05） from that in control soil without added C. At the end of the incubation period, amendment with glucose, a readily available C source, increased nitrate immobilization by 2.65 times and total N20-N emission by 33.7 times, as compared with maize straw amendment. Moreover, the differences in SON and total N20-N emission between the treatments with glucose and maize straw were significant （P 〈 0.05）. However, the total N20-N emission in the straw treatment was not significantly （P ~ 0.05） greater than that in the control. Straw amendment may be a potential option in agricultural practice for transformation of nitrate N to SON and minimization of N20 emitted as well as restriction of NO3-N leaching.Excessive amounts of nitrate have accumulated in many soils on the North China Plain due to the large amounts of chemical N fertilizers or manures used in combination with low carbon inputs. We investigated the potential of different carbon substrates added to transform soil nitrate into soil organic N (SON). A 56-d laboratory incubation experiment using the 15 N tracer (K15 NO3 ) technique was carried out to elucidate the proportion of SON derived from accumulated soil nitrate following amendment with glucose or maize straw at controlled soil temperature and moisture. The dynamics and isotopic abundance of mineral N (NO3 and NH+4 ) and SON and greenhouse gas (N2O and CO2 ) emissions during the incubation were investigated. Although carbon amendments markedly stimulated transformation of nitrate to newly formed SON, this was only a substitution effect of the newly formed SON with native SON because SON at the end of the incubation period was not significantly different (P > 0.05) from that in control soil without added C. At the end of the incubation period, amendment with glucose, a readily available C source, increased nitrate immobilization by 2.65 times and total N2O-N emission by 33.7 times, as compared with maize straw amendment. Moreover, the differences in SON and total N2O-N emission between the treatments with glucose and maize straw were significant (P < 0.05). However, the total N2O-N emission in the straw treatment was not significantly (P > 0.05) greater than that in the control. Straw amendment may be a potential option in agricultural practice for transformation of nitrate N to SON and minimization of N2O emitted as well as restriction of NO3-N leaching.

关 键 词：available C source carbon amendments greenhouse gases N immobilization 15N tracer 

分 类 号：S153[农业科学—土壤学]