h1. N2O emission from nitrification

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# h1

# N2O emission from nitrification

"Parton et al. 1996":http://onlinelibrary.wiley.com/doi/10.1029/96GB01455/abstract gives function

`N_{N2O} = N_{H2O} \cdot N_{pH} \cdot N_T \cdot (Kmx + Nmx \cdot N_{NH4})`

with $N_{N2O} = ((WFPS-b)/(a-b))^{d\cdot (b-a)/(a-c)} \cdot ((WFPS-c)/(a-c))^d$

- $WFPS$ is water filled pore space of the soil
- parameters $a$ to $d$ given for sandy and medium soil
- source for functions given as Doran et al. 1988

$N_{pH} = 0.56+1/\pi\cdot \arctan(\pi\cdot 0.45 \cdot(pH-5))$

- we ignore this limitation

$N_T = -0.06+0.13\cdot \exp(0.07 \cdot T_{soil})$

- based on data by Sabey et al. (1959)

$Kmx = 0.00038$ gN m$^{-2}$ d$^{-1}$

- N turnover coefficient
- site specific but given for different sites
- for natural soils given as 3.8 and 3.9 (gN ha$^{-1}$ d$^{-1}$)

$Nmx = 0.003$ gN m$^{-2}$ d$^{-1}$

- maximum nitrification flux of N$_2$O with excess NH$_4$.

$N_{NH4} = 1 - \exp(-0.0105\cdot NH4)$

- NH4 here given as $\mu$g N per g soil
- in the same range as gN m$^{-2}$ so that formula taken as it is

Process is incorporated in source:branches/nitrogen_rev2142/src/soil/littersom.c after mineralization.