Ammonia-oxidation as an engine to generate nitrous oxide in an intensively managed calcareous fluvo-aquic soil.
We combine field observations, microcosm, stoichiometry, and molecular and stable isotope techniques to quantify N2O generation processes in an intensively managed low carbon calcareous fluvo-aquic soil. All the evidence points to ammonia oxidation and linked nitrifier denitrification (ND) being the major processes generating N2O. When NH4(+)-based fertilizers are applied the soil will produce high N2O peaks which are inhibited almost completely by adding nitrification inhibitors. During ammonia oxidation with high NH4(+) concentrations (>80 mg N kg(-1)) the soil matrix will actively consume oxygen and accumulate high concentrations of NO2(-), leading to suboxic conditions inducing ND. Calculated N2O isotopomer data show that nitrification and ND accounted for 35-53% and 44-58% of total N2O emissions, respectively. We propose that slowing down nitrification and avoiding high ammonium concentrations in the soil matrix are important measures to reduce N2O emissions per unit of NH4(+)-based N input from this type of intensively managed soil globally.
1] College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China [2].
Tao
T
Huang
1] College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China [2].
Bing
B
Gao
College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
Xiao-Kang
XK
Hu
College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
Xing
X
Lu
Thünen Institute of Climate-Smart Agriculture, Bundesallee 50, 38116 Braunschweig, Germany.
Reinhard
R
Well
College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
Peter
P
Christie
IPM, Norwegian University of Life Sciences, Box 5003, N-1432 Ås, Norway.
Lars R
LR
Bakken
College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
Xiao-Tang
XT
Ju