!*****************************************************************!
!* *!
!* 4C (FORESEE) Simulation Model *!
!* *!
!* *!
!* Subroutines for: *!
!* SOIL_C/N - Programs *!
!* *!
!* Author: F. Suckow *!
!* *!
!* contains: *!
!* SOIL_CN *!
!* F_CNV(Cpool, Npool) *!
!* RMIN_T(temp) *!
!* RNIT_T(temp) *!
!* RMIN_W(water, xpv) *!
!* RNIT_W(water, xpv) *!
!* RMIN_P(phv) *!
!* RNIT_P(phv) *!
!* HUMLAY *!
!* DECOMP1(Copm, Nopm, cnv, kopm, ksyn, hdiff) *!
!* DECOMP2(Copm, Nopm, cnv, kopm, ksyn, hdiff) *!
!* MINLAY(jlay) *!
!* N_LEACH(jlay, NH4l, NO3l) *!
!* S_RESP(Copm_1, Chum_1) *!
!* *!
!* Copyright (C) 1996-2018 *!
!* Potsdam Institute for Climate Impact Reserach (PIK) *!
!* Authors and contributors see AUTHOR file *!
!* This file is part of 4C and is licensed under BSD-2-Clause *!
!* See LICENSE file or under: *!
!* http://www.https://opensource.org/licenses/BSD-2-Clause *!
!* Contact: *!
!* https://gitlab.pik-potsdam.de/foresee/4C *!
!* *!
!*****************************************************************!
SUBROUTINE soil_cn
! Soil C-N budget
use data_climate
use data_out
use data_simul
use data_soil
use data_soil_cn
use data_stand
implicit none
integer j, hnlay, ntr
real Copm_1, Chum_1 ! previous C-content of soil profile
real Nopm_1, Nhum_1 ! previous N-content of soil profile
real Cbc_1, Nbc_1 ! previous C- and N-content of biochar
real Nmin1, N_min_h
type(Coh_Obj), pointer :: p ! pointer to cohort list
! save previous state of soil C-content
Copm_1 = SUM(C_opm) + C_opm_stem
Chum_1 = SUM(C_hum)
Nopm_1 = SUM(N_opm) + N_opm_stem
Nhum_1 = SUM(N_hum)
N_min_h= N_min
if (flag_bc .gt. 0) then
Cbc_1 = SUM(C_bc)
Nbc_1 = SUM(N_bc)
else
Cbc_1 = 0.
Nbc_1 = 0.
endif
call humlay ! humus layer
! loop over mineral layers
do j=2,nlay
call minlay(j)
enddo ! loop over j (nlay)
! soil respiration
call s_resp(Copm_1, Chum_1, Cbc_1)
! daily values
Nleach = NH4_in + NO3_in
Nupt_d = SUM(Nupt)
N_an_tot = SUM(NH4) + SUM(NO3)
Nmin1 = Nopm_1 + Nhum_1 - SUM(N_opm) - SUM(N_hum)
if (flag_bc .gt. 0) then
Nmin1 = Nmin1 + Nbc_1 - SUM(N_bc)
endif
! yearly cumul. quantities
Nleach_c = Nleach_c + Nleach
Nupt_c = Nupt_c + Nupt_d
resps_c = resps_c + respsoil
p => pt%first
do while (associated(p))
ns = p%coh%species
ns = p%coh%species
ntr = p%coh%ntreea
svar(ns)%Ndem = svar(ns)%Ndem + ntr * p%coh%Ndemc_d
svar(ns)%Nupt = svar(ns)%Nupt + ntr * p%coh%Nuptc_d
p%coh%Nuptc_c = p%coh%Nuptc_c + p%coh%Nuptc_d
p%coh%Ndemc_c = p%coh%Ndemc_c + p%coh%Ndemc_d
p%coh%N_pool = p%coh%N_pool + p%coh%Nuptc_d
p => p%next
enddo ! p (cohorts)
if (flag_dayout .ge. 2) then
if (nlay .gt. 6) then
hnlay = 6
else
hnlay = nlay
endif
N_min_h = N_min - N_min_h
write (unit_soicna, '(A)') ''
write (unit_soicnd, '(A)') ''
endif
1000 FORMAT (2I5, 6F10.3, 6F10.1)
1100 FORMAT (2I5, 12F10.3)
1200 FORMAT (2I5, 4F10.3, 4F10.1, F10.2)
END subroutine soil_cn
!**************************************************************
real FUNCTION f_cnv(Cpool, Npool)
! C/N-ratio of a pool
! implicit none
real Cpool, Npool
if (Npool .lt. 1e-6) then
f_cnv = 0.
else
f_cnv = Cpool / Npool
endif
END function f_cnv
!**************************************************************
real FUNCTION rmin_t(temp, rkind)
! reduction of mineralization depending on soil temperature
use data_simul
implicit none
integer rkind
real temp, toptm, Q10
select case (rkind)
case(1)
toptm = 35.
Q10 = 2.9
rmin_t = exp(log(Q10) * ((temp-toptm)/10.)) ! Stanford
case(2)
toptm = 35.
Q10 = 2.9
rmin_t = Q10**((temp-toptm)*0.1) ! van't Hoff
case(4)
rmin_t = 1.
case default
toptm = 35.
Q10 = 2.9
rmin_t = exp(log(Q10) * ((temp-toptm)/10.)) ! Stanford
end select
END function rmin_t
!**************************************************************
real FUNCTION rnit_t(temp, rkind)
! reduction of nitrification depending on soil temperature
implicit none
integer rkind
real temp, toptn, Q10
select case (rkind)
case(1) ! Stanford
toptn = 30.
Q10 = 2.8
rnit_t = exp(log(Q10) * ((temp-toptn)/10.))
case(2) ! van't Hoff
toptn = 30.
Q10 = 2.8
rnit_t = Q10**((temp-toptn)*0.1) ! van't Hoff
case(3) ! SWAT-approach; Nitrif. only above 5�C
if (temp .gt. 5.) then
rnit_t = 0.041 *(temp-5.)
else
rnit_t = 0.
endif
case(4)
rnit_t = 1.
case default
toptn = 30.
Q10 = 2.8
rnit_t = exp(log(Q10) * ((temp-toptn)/10.)) ! Stanford
end select
END function rnit_t
!**************************************************************
real FUNCTION rmin_w(water, xpv)
! reduction of mineralization depending on soil water content
! xpv - pore volume
rmin_w = 4.0 * water * (1.0-water/xpv) / xpv
if (rmin_w .lt. 0.) rmin_w = 0.
END function rmin_w
!**************************************************************
real FUNCTION rnit_w(water, xpv, xfk, xwp, rkind)
! reduction of nitrification depending on soil water content
! xpv - pore volume
implicit none
integer rkind
real water, xpv, xfk, xwp, nfk, avwat
select case (rkind)
case(1) ! Franco
if (water .lt. 0.9*xpv) then
rnit_w = 4.0 * water * (1.0-water/xpv) / xpv
else
rnit_w = 1.
endif
if (rnit_w .lt. 0.) rnit_w = 0.
case(2) ! SWAT-Ansatz
nfk = xfk - xwp
avwat = water - xwp
if (avwat .lt. 0.25*nfk) then
rnit_w = avwat / 0.25 * nfk
else
rnit_w = 1.
endif
case default
if (water .lt. 0.9*xpv) then
rnit_w = 4.0 * water * (1.0-water/xpv) / xpv
else
rnit_w = 1.
endif
if (rnit_w .lt. 0.) rnit_w = 0.
end select
END function rnit_w
!**************************************************************
real FUNCTION rmin_p(phv)
! reduction of mineralization depending on pH-value
real, dimension(4) :: a = (/2.5, 4.0, 5.0, 8.0/), &
b = (/0.5, 0.8, 1.0, 1.0/)
call tab_int(a,b,4,phv,value)
rmin_p = value
END function rmin_p
!**************************************************************
real FUNCTION rnit_p(phv)
! reduction of nitrification depending on pH-value
real, dimension(4) :: a = (/2.5, 4.0, 6.0, 8.0/), &
b = (/0.1, 0.3, 1.0, 1.0/)
call tab_int(a,b,4,phv,value)
rnit_p = value
END function rnit_p
!**************************************************************
SUBROUTINE humlay
! C-N budget of the humus layer
! (including litter layer)
use data_climate
use data_depo
use data_inter
use data_out
use data_simul
use data_soil
use data_soil_cn
use help_soil_cn
use data_species
implicit none
integer, parameter:: double_prec = kind(0.0D0)
integer i
real (kind = double_prec):: N_hum_1, NH4_1, NO3_1 ! previous state of C- and N-pools
real (kind = double_prec):: N_hum_2, NH4_2, NO3_2 ! actual state of C- and N-pools
real (kind = double_prec):: hnh4, hno3, bilanz, hnhum, hncopm, nh4diff, nhdiff, hdiff, s_hdiff
real (kind = double_prec):: renit ! reduction function of nitrif.
real (kind = double_prec):: redtermc, redtermn ! red. terms of C-/ N-pools
real Copm, Nopm, hcnv, hcnv_bc, kopm, redopm, Nminl, Nmin1, redbc
logical ldecomp
real, external :: rmin_t, rmin_w, rnit_t, rnit_w, f_cnv
type (species_litter) :: sliti
if (flag_dayout .ge. 2) then
write (unit_soicnr, '(2I5,3E12.3)') time_cur, iday, rmin_t(temps(1), kmint), rmin_w(wats(1), pv(1)), rmin_phv(1)
endif
! reduction factors of mineralization and nitrification
remin = rmin_t(temps(1), kmint) * rmin_w(wats(1), pv(1)) * rmin_phv(1)
renit = rnit_t(temps(1), knitt) * rnit_w(wats(1), pv(1), field_cap(1), wilt_p(1), knitw) * rnit_phv(1)
! add deposition
if (flag_depo .eq. 2) then
NH_dep = NH_dep * prec_stand ! conversion g/l in g/m2
NO_dep = NO_dep * prec_stand
endif
NH4(1) = NH4(1) + NH_dep
NO3(1) = NO3(1) + NO_dep
Ndep_cum = Ndep_cum + NO_dep + NH_dep
! store state of previous step
N_hum_1 = N_hum(1)
NH4_1 = NH4(1)
NO3_1 = NO3(1)
khr = k_hum * remin
hexph = exp(-khr)
knr = k_nit * renit
if (abs(knr-khr) .le. 1E-6) knr = knr + 1E-6
hexpn = exp(-knr)
! reduction of C- and N-humus-pool by mineralization,
redtermc = C_hum(1) * hexph ! part of equation II
redtermn = N_hum_1 * hexph ! -"-
! NH4-pool
if (NH4_1 .gt. 1E-6) then
term1 = NH4_1 * hexpn ! part of equ. III
else
term1 = NH4_1
endif
term3 = N_hum_1 * khr * (hexph-hexpn) / (knr-khr)
if (cnv_hum(1) .lt. 1e-8) cnv_hum(1) = 20.
cnvh = 1./cnv_hum(1)
redopm = 1.
redbc = 1.
slit_1 = slit
ldecomp = .TRUE.
do while (ldecomp)
! Decomposition of dead biomass
Copm = 0.
Nopm = 0.
C_opm_stem = 0.
N_opm_stem = 0.
reptermc = 0.
reptermn = 0.
term2 = 0.
term4 = 0.
s_hdiff = 0.
! Decomposition of dead biomass fractions
do i=1,nspecies
sliti = slit_1(i)
hdiff = 0.
if (sliti%C_opm_fol .gt. 1e-8) then
kopm = redopm * spar(i)%k_opm_fol
if (kopm .ge. 1e-8) then
sliti%cnv_opm_fol = f_cnv(sliti%C_opm_fol, sliti%N_opm_fol)
call decomp1(sliti%C_opm_fol, sliti%N_opm_fol, sliti%cnv_opm_fol, &
kopm, spar(i)%k_syn_fol, hdiff)
s_hdiff = s_hdiff + hdiff
endif
endif
if (sliti%C_opm_frt(1) .gt. 1e-8) then
kopm = redopm * spar(i)%k_opm_frt
if (kopm .ge. 1e-8) then
sliti%cnv_opm_frt = f_cnv(sliti%C_opm_frt(1), sliti%N_opm_frt(1))
call decomp1(sliti%C_opm_frt(1), sliti%N_opm_frt(1), sliti%cnv_opm_frt, &
kopm, spar(i)%k_syn_frt, hdiff)
s_hdiff = s_hdiff + hdiff
endif
endif
if (sliti%C_opm_tb .gt. 1e-8) then
kopm = redopm * spar(i)%k_opm_tb
if (kopm .ge. 1e-8) then
sliti%cnv_opm_tb = f_cnv(sliti%C_opm_tb, sliti%N_opm_tb)
call decomp1(sliti%C_opm_tb, sliti%N_opm_tb, sliti%cnv_opm_tb, &
kopm, spar(i)%k_syn_tb, hdiff)
s_hdiff = s_hdiff + hdiff
endif
endif
select case (flag_decomp)
case (0, 10, 20, 30, 40)
if (sliti%C_opm_crt(1) .gt. 1e-8) then
kopm = redopm * spar(i)%k_opm_crt
if (kopm .ge. 1e-8) then
sliti%cnv_opm_crt = f_cnv(sliti%C_opm_crt(1), sliti%N_opm_crt(1))
call decomp1(sliti%C_opm_crt(1), sliti%N_opm_crt(1), sliti%cnv_opm_crt, &
kopm, spar(i)%k_syn_crt, hdiff)
s_hdiff = s_hdiff + hdiff
endif
endif
if (sliti%C_opm_stem .gt. 1e-8) then
kopm = redopm * spar(i)%k_opm_stem
if (kopm .ge. 1e-8) then
sliti%cnv_opm_stem = f_cnv(sliti%C_opm_stem, sliti%N_opm_stem)
call decomp1(sliti%C_opm_stem, sliti%N_opm_stem, sliti%cnv_opm_stem, &
kopm, spar(i)%k_syn_stem, hdiff)
s_hdiff = s_hdiff + hdiff
endif
endif
case (1, 11, 21, 31, 41)
if (sliti%C_opm_crt(1) .gt. 1e-8) then
kopm = redopm * spar(i)%k_opm_crt
if (kopm .ge. 1e-8) then
sliti%cnv_opm_crt = f_cnv(sliti%C_opm_crt(1), sliti%N_opm_crt(1))
call decomp2(sliti%C_opm_crt(1), sliti%N_opm_crt(1), sliti%cnv_opm_crt, &
kopm, spar(i)%k_syn_crt, hdiff)
s_hdiff = s_hdiff + hdiff
endif
endif
if (sliti%C_opm_stem .gt. 1e-8) then
kopm = redopm * spar(i)%k_opm_stem
if (kopm .ge. 1e-8) then
sliti%cnv_opm_stem = f_cnv(sliti%C_opm_stem, sliti%N_opm_stem)
call decomp2(sliti%C_opm_stem, sliti%N_opm_stem, sliti%cnv_opm_stem, &
kopm, spar(i)%k_syn_stem, hdiff)
s_hdiff = s_hdiff + hdiff
endif
endif
end select
! pools of dead biomass without stems
Copm = Copm + sliti%C_opm_fol + sliti%C_opm_frt(1) + sliti%C_opm_crt(1) + sliti%C_opm_tb
Nopm = Nopm + sliti%N_opm_fol + sliti%N_opm_frt(1) + sliti%N_opm_crt(1) + sliti%N_opm_tb
! dead stems
C_opm_stem = C_opm_stem + sliti%C_opm_stem
N_opm_stem = N_opm_stem + sliti%N_opm_stem
slit(i) = sliti
enddo
! Decomposition of biochar
if (flag_bc .gt. 0) then
if (C_bc(1) .gt. 1e-8) then
kbc = redbc * k_bc
if (kbc .ge. 1e-8) then
hcnv_bc = f_cnv(C_bc(1), N_bc(1))
call decomp1(C_bc(1), N_bc(1), hcnv_bc, kbc, k_syn_bc, hdiff)
s_hdiff = s_hdiff + hdiff
endif
endif
endif
ldecomp = .FALSE.
C_opm(1) = Copm
N_opm(1) = Nopm
! C- and N-humus-pool: reduction by mineralization, supply by turnover of organic primary matter
C_hum(1) = redtermc + reptermc
N_hum_2 = redtermn + reptermn
N_hum(1) = N_hum_2
! ammonium pool
hnh4 = term1 + term2 + term3 + khr/(knr-khr) * term4
NH4(1) = hnh4
nhdiff = N_hum_1 - N_hum_2
nh4diff = NH4_1 - NH4(1)
Nminl = hnh4 - NH4_1 - NO3(1) ! daily net min.
! nitrat pool from balance
hno3 = NO3_1 + s_hdiff + nhdiff + nh4diff
NO3(1) = hno3
if (hnh4 .lt. 0.0 .or. hno3 .lt. 0.0) then
redopm = 0.9 * redopm
if (redopm .ge. 1E-8) then
ldecomp = .TRUE.
else
if (NH4(1) .lt. 1E-10) NH4(1) = 0.
if (NO3(1) .lt. 1E-10) NO3(1) = 0.
endif
endif
Nminl = Nminl + NO3(1) ! daily net min. per layer
enddo ! ldecomp
Nmin(1) = Nminl
N_min = N_min + Nminl ! cumul. yearly net min.
call n_leach(1) ! without balance
! new balance after leaching
NH4(1) = NH4(1) - NH4_in
NO3(1) = NO3(1) - NO3_in
call n_upt(1) ! with balance
if (flag_dayout .ge. 2) then
write (unit_soicna, '(2I5,E12.3)', advance='no') time_cur, iday, remin
write (unit_soicnd, '(2I5,E12.3)', advance='no') time_cur, iday, Nminl
endif
END subroutine humlay
!**************************************************************
SUBROUTINE decomp1(Copm, Nopm, cnv, kopm, ksyn, hdiff)
! Decomposition of dead biomass fractions per species
use help_soil_cn
implicit none
integer, parameter:: double_prec = kind(0.0D0)
real Copm, Nopm ! C- and N-pool of primary organic matter fraction
real kopm, ksyn ! mineralisation and synthesis coeff. of opm-fraction
real kor ! reduced mineralisation coeff. of opm-fraction
real N_opm_1, C_opm_1 ! previous state of C- and N-pools
real hexpo ! exponential part
real cnv ! C/N-ratio of opm-fraction
real exterm
real (kind = double_prec):: hdiff
real gamma
! store state of previous step
C_opm_1 = Copm
N_opm_1 = Nopm
kor = kopm * remin ! reduction of miner. coeff.
! avoid denominators near zero
if (abs(kor-khr) .lt. 1E-6) kor = kor + 1E-6
if (abs(kor-knr) .lt. 1E-6) kor = kor + 1E-6
hexpo = exp(-kor)
Copm = C_opm_1 * hexpo ! equations II
Nopm = N_opm_1 * hexpo ! -"-
! reproduction of C- and N-humus-pool by turnover of organic primary matter
exterm = hexph - hexpo
gamma = cnv * cnvh
if (abs(kor-khr) .gt. 1E-6) then
reptermc = reptermc + C_opm_1 * ksyn * kor * exterm / (kor-khr) ! part of equ. II
reptermn = reptermn + N_opm_1 * gamma*ksyn * kor * exterm / (kor-khr) ! part of equ. II
endif
! change of ammonium pool
if (abs(kor-knr) .gt. 1E-6) then
term2 = term2 + (1.-gamma*ksyn)*kor * N_opm_1 * (hexpn - hexpo) / (kor - knr) ! part of equ. III
endif
if ((abs(kor-khr) .gt. 1E-6) .and. (abs(kor-knr) .gt. 1E-6)) then
term4 = term4 + gamma*ksyn*kor * N_opm_1 & ! part of equ. III
* ((kor-khr) * hexpn + (knr-kor) * hexph + (khr-knr) * hexpo) &
/ ((khr - kor) * (kor - knr))
endif
hdiff = N_opm_1 - Nopm ! N-change rate in organic primary matter
END subroutine decomp1
!**************************************************************
SUBROUTINE decomp2(Copm, Nopm, cnv, kopm, ksyn, hdiffn)
! Decomposition of dead stem biomass per species
use help_soil_cn
implicit none
integer, parameter:: double_prec = kind(0.0D0)
real Copm, Nopm ! C- and N-pool of primary organic matter fraction
real kopm, ksyn ! mineralisation and synthesis coeff. of opm-fraction
real kor ! reduced mineralisation coeff. of opm-fraction
real N_opm_1, C_opm_1 ! previous state of C- and N-pools
real hexpo ! exponential part
real cnv ! C/N-ratio of opm-fraction
real (kind = double_prec):: hdiffn, hdiffc
! store state of previous step
C_opm_1 = Copm
N_opm_1 = Nopm
kor = kopm * remin ! reduction of miner. coeff.
! avoid denominators near zero
if (abs(kor) .lt. 1E-6) kor = kor + 1E-6
hexpo = exp(-kor)
Copm = C_opm_1 * hexpo ! equations II
Nopm = N_opm_1 * hexpo ! -"-
! reproduction of C- and N-humus-pool by turnover of organic primary matter
hdiffn = N_opm_1 - Nopm ! N-change rate in organic primary matter
hdiffc = hdiffn / cnvh
reptermn = reptermn + hdiffn
reptermc = reptermc + hdiffc
END subroutine decomp2
!**************************************************************
SUBROUTINE minlay(jlay)
! C-N budget of a mineral layer
use data_climate
use data_out
use data_simul
use data_soil
use data_soil_cn
use help_soil_cn
use data_species
implicit none
! input:
integer jlay ! number of actual layer
!------------------------------------------------------------
integer, parameter:: double_prec = kind(0.0D0)
integer i
real (kind = double_prec):: N_hum_1, NH4_1, NO3_1 ! previous state of C- and N-pools
real (kind = double_prec):: hnh4, hno3, bilanz, hnhum, hncopm, nh4diff, nhdiff, hdiff, s_hdiff
real (kind = double_prec):: renit ! reduction function of nitrif.
real (kind = double_prec):: redtermc, redtermn ! red. terms of C-/ N-pools
real Copm, Nopm, hcnv, hcnv_bc, kopm, redopm, Nminl, Nmin1, redbc
real, dimension(nspecies):: Copm_frt_1, Nopm_frt_1, Copm_crt_1, Nopm_crt_1
logical ldecomp
real, external :: rmin_t, rmin_w, rnit_t, rnit_w, f_cnv
! reduction factors of mineralization and nitrification
remin = rmin_t(temps(jlay), kmint) * rmin_w(wats(jlay), pv(jlay)) * rmin_phv(jlay)
renit = rnit_t(temps(jlay), knitt) * rnit_phv(jlay) * &
rnit_w(wats(jlay), pv(jlay), field_cap(jlay), wilt_p(jlay), knitw)
if (flag_dayout .eq. 3) then
write (1122, *) 'minlay ', iday, jlay
endif
! add N transport from above layer
NH4(jlay) = NH4(jlay) + NH4_in
NO3(jlay) = NO3(jlay) + NO3_in
! store state of previous step
N_hum_1 = N_hum(jlay)
NH4_1 = NH4(jlay)
NO3_1 = NO3(jlay)
Nopm_frt_1 = slit%N_opm_frt(jlay)
Copm_frt_1 = slit%C_opm_frt(jlay)
Nopm_crt_1 = slit%N_opm_crt(jlay)
Copm_crt_1 = slit%C_opm_crt(jlay)
redopm = 1.
redbc = 1.
khr = k_hum_r * remin
hexph = exp(-khr)
knr = k_nit * renit
if (abs(knr-khr) .le. 1E-6) knr = knr + 1E-6
hexpn = exp(-knr)
! reduction of C- and N-humus-pool by mineralization,
redtermc = C_hum(jlay) * hexph ! part of equation II
redtermn = N_hum_1 * hexph ! -"-
! NH4-pool
term1 = NH4_1 * hexpn ! part of equ. III
term3 = N_hum_1 * khr * (hexph-hexpn) / (knr-khr)
if (cnv_hum(jlay) .lt. 1e-8) then
if (cnv_hum(jlay-1) .ge. 1e-8) then
cnv_hum(jlay) = cnv_hum(jlay-1)
else
cnv_hum(jlay) = 20.
endif
endif
cnvh = 1./cnv_hum(jlay)
ldecomp = .TRUE.
do while (ldecomp)
! Decomposition of dead biomass
reptermc = 0.
reptermn = 0.
term2 = 0.
term4 = 0.
s_hdiff = 0.
do i=1,nspecies
Nopm = Nopm_frt_1(i)
kopm = redopm * spar(i)%k_opm_frt
if (Nopm .ge. 1e-8 .and. kopm .ge. 1e-8) then
Copm = Copm_frt_1(i)
hcnv = f_cnv(Copm, Nopm)
if ((time .eq.1) .and. (jlay .gt. 155)) then
endif
call decomp1(Copm, Nopm, hcnv, kopm, spar(i)%k_syn_frt, hdiff)
slit(i)%C_opm_frt(jlay) = Copm
slit(i)%N_opm_frt(jlay) = Nopm
cnv_opm(jlay) = hcnv
else
hdiff = 0.
endif ! Nopm
s_hdiff = s_hdiff + hdiff
Nopm = Nopm_crt_1(i)
kopm = redopm * spar(i)%k_opm_crt
if (Nopm .ge. 1e-8 .and. kopm .ge. 1e-8) then
Copm = Copm_crt_1(i)
hcnv = f_cnv(Copm, Nopm)
if ((time .eq.1) .and. (jlay .gt. 155)) then
endif
select case (flag_decomp)
case (0, 10, 20, 30, 40)
call decomp1(Copm, Nopm, hcnv, kopm, spar(i)%k_syn_crt, hdiff)
case (1, 11, 21, 31, 41)
call decomp2(Copm, Nopm, hcnv, kopm, spar(i)%k_syn_crt, hdiff)
end select
slit(i)%C_opm_crt(jlay) = Copm
slit(i)%N_opm_crt(jlay) = Nopm
cnv_opm(jlay) = hcnv
else
hdiff = 0.
endif ! Nopm
s_hdiff = s_hdiff + hdiff
enddo ! nspecies
! Decomposition of biochar
if (flag_bc .gt. 0) then
if (C_bc(jlay) .gt. 1e-8) then
kbc = redbc * k_bc
if (kbc .ge. 1e-8) then
hcnv_bc = f_cnv(C_bc(jlay), N_bc(jlay))
call decomp1(C_bc(jlay), N_bc(jlay), hcnv_bc, kbc, k_syn_bc, hdiff)
s_hdiff = s_hdiff + hdiff
endif
endif
endif
ldecomp = .FALSE.
C_opm(jlay) = SUM(slit%C_opm_frt(jlay)) + SUM(slit%C_opm_crt(jlay))
N_opm(jlay) = SUM(slit%N_opm_frt(jlay)) + SUM(slit%N_opm_crt(jlay))
! C- and N-humus-pool: reduction by mineralization,
! supply by turnover of organic primary matter
C_hum(jlay) = redtermc + reptermc
hnhum = redtermn + reptermn
N_hum(jlay) = hnhum
! ammonium pool
hnh4 = term1 + term2 + term3 + khr/(knr-khr) * term4
NH4(jlay) = hnh4
nhdiff = N_hum_1 - N_hum(jlay)
nh4diff = NH4_1 - NH4(jlay)
bilanz = NO3(jlay) + s_hdiff &
+ nhdiff + nh4diff
Nminl = NH4(jlay) - NH4_1 - NO3(jlay) ! daily net min.
! nitrate pool from balance
hno3 = NO3_1 + s_hdiff + nhdiff + nh4diff
NO3(jlay) = hno3
if (hnh4 .lt. 0.0 .or. hno3 .lt. 0.0) then
redopm = 0.9 * redopm
if (redopm .ge. 1E-8) then
ldecomp = .TRUE.
else
if (NH4(jlay) .lt. 1E-10) NH4(jlay) = 0.
if (NO3(jlay) .lt. 1E-10) NO3(jlay) = 0.
endif
endif
Nminl = Nminl + NO3(jlay) ! daily net min. per layer
bilanz = bilanz - NO3(jlay)
enddo ! ldecomp
Nmin(jlay) = Nminl
N_min = N_min + Nminl ! cumul. yearly net min.
call n_leach(jlay) ! without balance
! new balance after leaching
NH4(jlay) = NH4(jlay) - NH4_in
NO3(jlay) = NO3(jlay) - NO3_in
call n_upt(jlay) ! with balance
if (flag_dayout .ge. 2) then
write (unit_soicna, '(E12.3)', advance='no') remin
write (unit_soicnd, '(E12.3)', advance='no') Nminl
endif
END subroutine minlay
!**************************************************************
SUBROUTINE n_leach(jlay)
! N leaching and new balance
! Addition of deposition to the anorganic pools
use data_climate
use data_simul
use data_soil
use data_soil_cn
use help_soil_cn
use data_species
implicit none
! input:
integer jlay ! number of actual layer
!-----------------------------------------------------------
real NH4f, NO3f ! free available NH4-, NO3-N
real perc_w ! relative part of percolated water
! NH4 and NO3 partly fixed
if (NH4(jlay) .lt. 1E-25) then
continue
endif
NH4f = NH4(jlay) * pNH4f
NO3f = NO3(jlay) * pNO3f
! relative part of percolated water
perc_w = perc(jlay) / (wats(jlay) + perc(jlay) + wupt_r(jlay) + wupt_ev(jlay))
! N transport
NH4_in = NH4f * perc_w
NO3_in = NO3f * perc_w
END subroutine n_leach
!**************************************************************
SUBROUTINE s_resp(Copm_1, Chum_1, Cbc_1)
! Estimation of soil respiration
use data_climate
use data_simul
use data_soil
use data_soil_cn
use help_soil_cn
use data_species
implicit none
! input:
real Copm_1, Chum_1, Cbc_1 ! previous C-content of soil profile
real Sum_C_opm, Sum_C_hum, Sum_C_bc
!-----------------------------------------------------------
Sum_C_opm = SUM(C_opm) + C_opm_stem
Sum_C_hum = SUM(C_hum)
respsoil = Copm_1 + Chum_1 - Sum_C_opm - Sum_C_hum
if (flag_bc .gt. 0) then
Sum_C_bc = SUM(C_bc)
respsoil = respsoil + Cbc_1 - Sum_C_bc
endif
END subroutine s_resp
!**************************************************************
SUBROUTINE s
!
use data_climate
use data_simul
use data_soil
use data_soil_cn
use help_soil_cn
use data_species
implicit none
END subroutine s
!**************************************************************