subroutine soil_nutcarb_init (isol) !! ~ ~ ~ PURPOSE ~ ~ ~ !! this subroutine initializes soil chemical properties use hru_module, only : hru, ihru, sol_plt_ini use soil_module use soil_data_module use basin_module use organic_mineral_mass_module implicit none integer, intent (in) :: isol !none |soil (hru) number integer :: nly = 0 integer :: ly = 0 integer :: isolt = 0 !counter |soil plant initialization file pointer integer :: isol_pl = 0 !counter |soil nutrient initialization pointer (nutrients.sol) real :: wt1 = 0. !kg/ha |weight of the soil layer real :: dep_frac = 0. !0-1 |fraction of surface concentration at depth real :: frac_hum_active = 0. !0-1 |fraction of humus in active pool - old SWAT real :: frac_hum_microb = 0. !0-1 |fraction of humus in microbial pool - CENTURY real :: frac_hum_slow = 0. !0-1 |fraction of humus in slow pool - CENTURY real :: frac_hum_passive = 0. !0-1 |fraction of humus in passive pool - CENTURY real :: actp = 0. real :: solp = 0. real :: ssp = 0. real :: psp = 0. ! | nly = soil(ihru)%nly !! set soil nutrient initialization from nutrients.sol isol_pl = hru(ihru)%dbs%soil_plant_init isolt = sol_plt_ini(isol_pl)%nut ! isolt = 0 = default in type !! set soil carbon soil1(ihru)%cbn(1) = max(.001, soildb(isol)%ly(1)%cbn) !! assume 0.001% carbon if zero !! calculate percent carbon for lower layers using exponential decrease do ly = 2, nly dep_frac = Exp(-solt_db(isolt)%exp_co * soil(ihru)%phys(ly)%d) soil1(ihru)%cbn(ly) = soil1(ihru)%cbn(1) * dep_frac end do !! calculate initial nutrient contents of layers, profile and !! average in soil for the entire watershed do ly = 1, nly soil(ihru)%phys(ly)%conv_wt = soil(ihru)%phys(ly)%bd * soil(ihru)%phys(ly)%thick / 100. ! mg/kg => kg/ha wt1 = soil(ihru)%phys(ly)%conv_wt !! set initial mineral pools - no3 dep_frac = Exp(-solt_db(isolt)%exp_co * soil(ihru)%phys(ly)%d) if (solt_db(isolt)%nitrate > 1.e-9) then soil1(ihru)%mn(ly)%no3 = solt_db(isolt)%nitrate * dep_frac else soil1(ihru)%mn(ly)%no3 = 7. * dep_frac end if soil1(ihru)%mn(ly)%no3 = soil1(ihru)%mn(ly)%no3 * wt1 !! mg/kg => kg/ha !set initial labile P pool if (solt_db(isolt)%lab_p > 1.e-9) then soil1(ihru)%mp(ly)%lab = solt_db(isolt)%lab_p * dep_frac else !! assume initial concentration of 5 mg/kg soil1(ihru)%mp(ly)%lab = 5. * dep_frac end if soil1(ihru)%mp(ly)%lab = soil1(ihru)%mp(ly)%lab * wt1 !! mg/kg => kg/ha !! set active mineral P pool based on dynamic PSP MJW if (bsn_cc%sol_P_model == 1) then !! Allow Dynamic PSP Ratio !! convert to concentration solp = soil1(ihru)%mp(ly)%lab / wt1 !! PSP = -0.045*log (% clay) + 0.001*(Solution P, mg kg-1) - 0.035*(% Organic C) + 0.43 if (soil(ihru)%phys(ly)%clay > 0.) then psp = -0.045 * log(soil(ihru)%phys(ly)%clay) + (0.001 * solp) psp = psp - (0.035 * soil1(ihru)%cbn(ly)) + 0.43 endif !! Limit PSP range if (psp < .10) then psp = 0.10 else if (psp > 0.7) then psp = 0.7 end if else psp = bsn_prm%psp end if soil1(ihru)%mp(ly)%act = soil1(ihru)%mp(ly)%lab * (1. - psp) / psp !! Set Stable pool based on dynamic coefficient if (bsn_cc%sol_P_model == 1) then !! From White et al 2009 !! convert to concentration for ssp calculation actp = soil1(ihru)%mp(ly)%act / wt1 solp = soil1(ihru)%mp(ly)%lab / wt1 !! estimate Total Mineral P in this soil based on data from sharpley 2004 ssp = 25.044 * (actp + solp)** (-0.3833) !!limit SSP Range if (ssp > 7.) ssp = 7. if (ssp < 1.) ssp = 1. soil1(ihru)%mp(ly)%sta = ssp * (soil1(ihru)%mp(ly)%act + soil1(ihru)%mp(ly)%lab) else !! the original code soil1(ihru)%mp(ly)%sta = 4. * soil1(ihru)%mp(ly)%act end if end do !! set initial organic pools - originally by Zhang do ly = 1, nly !initialize total soil organic pool - no litter !kg/ha = mm * t/m3 * m/1,000 mm * 1,000 kg/t * 10,000 m2/ha soil1(ihru)%tot(ly)%m = 10000. * soil(ihru)%phys(ly)%thick * soil(ihru)%phys(ly)%bd soil1(ihru)%tot(ly)%c = soil1(ihru)%tot(ly)%m * soil1(ihru)%cbn(ly) / 100. soil1(ihru)%tot(ly)%n = soil1(ihru)%tot(ly)%c / 10. !assume 10:1 C:N ratio soil1(ihru)%tot(ly)%p = soil1(ihru)%tot(ly)%c / 100. !assume 100:1 C:P ratio !set active humus fraction for original SWAT model if (solt_db(isolt)%fr_hum_act < 1.e-9) solt_db(isolt)%fr_hum_act = .02 frac_hum_active = solt_db(isolt)%fr_hum_act !initialize oringinal SWAT active and stable organic pools (from EPIC) !initialize active humus pool soil1(ihru)%hact(ly)%m = frac_hum_active * soil1(ihru)%tot(ly)%m soil1(ihru)%hact(ly)%c = frac_hum_active * soil1(ihru)%tot(ly)%c soil1(ihru)%hact(ly)%n = soil1(ihru)%hact(ly)%c / solt_db(isolt)%hum_c_n soil1(ihru)%hact(ly)%p = soil1(ihru)%hact(ly)%c / solt_db(isolt)%hum_c_p !initialize stable humus pool soil1(ihru)%hsta(ly)%m = (1. - frac_hum_active) * soil1(ihru)%tot(ly)%m soil1(ihru)%hsta(ly)%c = (1. - frac_hum_active) * soil1(ihru)%tot(ly)%c soil1(ihru)%hsta(ly)%n = soil1(ihru)%hsta(ly)%c / solt_db(isolt)%hum_c_n soil1(ihru)%hsta(ly)%p = soil1(ihru)%hsta(ly)%c / solt_db(isolt)%hum_c_p !set root and incorporated residue pool to zero soil1(ihru)%rsd(ly) = orgz !initialize CENTURY organic pools !set soil humus fractions for CENTURY from DSSAT frac_hum_microb = 0.02 frac_hum_slow = 0.54 frac_hum_passive = 0.44 !initialize passive humus pool soil1(ihru)%hp(ly)%m = frac_hum_passive * soil1(ihru)%tot(ly)%m soil1(ihru)%hp(ly)%c = .42 * frac_hum_passive * soil1(ihru)%tot(ly)%c !assume 42% C soil1(ihru)%hp(ly)%n = soil1(ihru)%hp(ly)%c / 10. !assume 10:1 C:N ratio soil1(ihru)%hp(ly)%p = soil1(ihru)%hp(ly)%c / 80. !assume 80:1 C:P ratio !initialize slow humus pool soil1(ihru)%hs(ly)%m = frac_hum_slow * soil1(ihru)%tot(ly)%m soil1(ihru)%hs(ly)%c = .42 * frac_hum_slow * soil1(ihru)%tot(ly)%c !assume 42% C soil1(ihru)%hs(ly)%n = soil1(ihru)%hs(ly)%c / 10. !assume 10:1 C:N ratio soil1(ihru)%hs(ly)%p = soil1(ihru)%hs(ly)%c / 80. !assume 80:1 C:P ratio !initialize microbial pool soil1(ihru)%microb(ly)%m = frac_hum_microb * soil1(ihru)%tot(ly)%m soil1(ihru)%microb(ly)%c = .42 * frac_hum_microb * soil1(ihru)%tot(ly)%c !assume 42% C soil1(ihru)%microb(ly)%n = soil1(ihru)%microb(ly)%c / 8. !assume 8:1 C:N ratio soil1(ihru)%microb(ly)%p = soil1(ihru)%microb(ly)%c / 80. !assume 80:1 C:P ratio !initialize metabolic litter pool soil1(ihru)%meta(ly)%m = soil1(ihru)%tot(ly)%m / 1000. !t/ha - kg/ha soil1(ihru)%meta(ly)%c = .42 * soil1(ihru)%meta(ly)%c !assume 42% C soil1(ihru)%meta(ly)%n = soil1(ihru)%meta(ly)%c / 150. !assume 150:1 C:N ratio soil1(ihru)%meta(ly)%p = soil1(ihru)%meta(ly)%c / 1500. !assume 1500:1 C:P ratio !initialize structural litter pool soil1(ihru)%str(ly)%m = soil1(ihru)%meta(ly)%m soil1(ihru)%str(ly)%c = .42 * soil1(ihru)%str(ly)%c !assume 42% C soil1(ihru)%str(ly)%n = soil1(ihru)%lig(ly)%c / 150. !assume 150:1 C:N ratio soil1(ihru)%str(ly)%p = soil1(ihru)%lig(ly)%c / 1500. !assume 1500:1 C:P ratio !initialize lignon litter pool soil1(ihru)%lig(ly)%m = .8 * soil1(ihru)%str(ly)%m soil1(ihru)%lig(ly)%c = .8 * soil1(ihru)%str(ly)%c soil1(ihru)%lig(ly)%n = .2 * soil1(ihru)%str(ly)%c soil1(ihru)%lig(ly)%p = .02 * soil1(ihru)%str(ly)%c soil1(ihru)%tot(ly)%c = soil1(ihru)%hs(ly)%c + soil1(ihru)%hp(ly)%c + soil1(ihru)%microb(ly)%c + & soil1(ihru)%meta(ly)%c + soil1(ihru)%str(ly)%c + soil1(ihru)%lig(ly)%c !initialize water soluble pool !soil1(ihru)%water(ly)%m = !soil1(ihru)%water(ly)%c = !soil1(ihru)%water(ly)%n = !soil1(ihru)%water(ly)%p = end do return end subroutine soil_nutcarb_init