Mitrification－Denitrification Lossof Added Nitrogenin Flooded Rice Rhizosphere  

作　　者：LI XIN-HUI ZHU ZHAO-LIANG CAI GUI-XIN ZHOU KE-YU and CAO YA-CHENG(Institute of Soil Science, Academia Sinica, P.O .Box 821 . Nanjing (China)) 

出　　处：《Pedosphere》1994年第2期145-152,共8页土壤圈（英文版）

摘　　要：Nitrification-denitrification losses of ￣15N-labelled nitrate and ammonium applied to the rhizosphere andnonrhizosphere of flooded rice were evaluated in 2 greenhouse rhizobox experiments. The loss of added Nvia denitrification was estimated directly by measuring the total fluxes of (N_2O+N_2)￣15N. It was found that 67% and51%-56% of ￣15N-nitrate added to rice rhizosphere were lost as (N_2O+N_)-￣15N in the 2 experiments, respectively,which were comparable to that added to nonrhizosphere soil (70%and47%, respectively), implying that tbedenitrifying activity in rice rhizosphere was as high as that in nonrhizosphere soil. However, only trace amounts(0-0.3% of added N) were recovered as (N_2O+N_2)-￣15N when ￣15N-ammonium was applied to either rhizosphere ornonrhizosphere, which seems to indicate that the nitrifying activity in the either rhizosphere or nonrhizosphere soilswas quite low. The apparent denitrification calculated from ￣15N balance studies was 10%-47% higher than the totalflux of (N_2O+N_2)-￣15N. Reasons for the large differences can not be explained satisfactorily. Though the denitrifyingactivity in rhizospbere was high and comparable to that in nonrhizosphere soil, presumably due to the low nitrifyingactivity and/ or the strong competition of N uptake against denitrification, the nitrification-denitrification takingplace in rhizosphere could not be an important mechanism of loss of ammonium N in flooded rice-soil system.Ｍｉｔｒｉｆｉｃａｔｉｏｎ－ＤｅｎｉｔｒｉｆｉｃａｔｉｏｎＬｏｓｓｏｆＡｄｄｅｄＮｉｔｒｏｇｅｎｉｎＦｌｏｏｄｅｄＲｉｃｅＲｈｉｚｏｓｐｈｅｒｅＬＩＸＩＮ－ＨＵＩ；ＺＨＵＺＨＡＯ－ＬＩＡＮＧ；ＣＡＩＧＵＩ－ＸＩＮ；ＺＨＯＵＫＥ－ＹＵａｎｄＣＡＯＹＡ－...

关 键 词：DENITRIFICATION ￣15N balance NITRIFICATION RHIZOBOX RHIZOSPHERE 

分 类 号：S143.1[农业科学—肥料学] S511.062[农业科学—农业基础科学]