subroutine pl_fert (ifrt, frt_kg, fertop) !! ~ ~ ~ PURPOSE ~ ~ ~ !! this subroutine applies N and P specified by date and !! amount in the management file (.mgt) !! ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ !! ~ ~ ~ SUBROUTINES/FUNCTIONS CALLED ~ ~ ~ !! SWAT: Erfc !! ~ ~ ~ ~ ~ ~ END SPECIFICATIONS ~ ~ ~ ~ ~ ~ use mgt_operations_module use fertilizer_data_module use basin_module use organic_mineral_mass_module use hru_module, only : ihru, fertn, fertp, fertnh3, fertno3, fertorgn, fertorgp, fertp, & fertsolp implicit none real, parameter :: rtof=0.5 !none |weighting factor used to partition the ! |organic N & P concentration of septic effluent ! |between the fresh organic and the stable ! |organic pools integer :: j = 0 !none |counter integer :: l = 0 !none |counter integer, intent (in) :: ifrt ! |fertilizer type from fert data base integer, intent (in) :: fertop ! | real, intent (in) :: frt_kg !kg/ha |amount of fertilizer applied real :: xx = 0. ! | !!added by zhang !!====================== real :: X1 = 0. real :: X8 = 0. real :: X10 = 0. real :: XXX = 0. real :: YY = 0. real :: ZZ = 0. real :: XZ = 0. real :: YZ = 0. real :: RLN = 0. real :: orgc_f = 0. j = ihru X1 = 0. X8 = 0. X10 = 0. XXX = 0. YY = 0. ZZ = 0. XZ = 0. YZ = 0. RLN = 0. orgc_f = 0. !!added by zhang !!====================== !j = jj do l = 1, 2 xx = 0. if (l == 1) then xx = chemapp_db(fertop)%surf_frac else xx = 1. - chemapp_db(fertop)%surf_frac endif soil1(j)%mn(l)%no3 = soil1(j)%mn(l)%no3 + xx * frt_kg * & (1. - fertdb(ifrt)%fnh3n) * fertdb(ifrt)%fminn if (bsn_cc%cswat == 0) then soil1(j)%tot(l)%n = soil1(j)%tot(l)%n + rtof * xx * frt_kg * & fertdb(ifrt)%forgn soil1(j)%hact(l)%n = soil1(j)%hact(l)%n + (1. - rtof) * xx * & frt_kg * fertdb(ifrt)%forgn soil1(j)%tot(l)%p = soil1(j)%tot(l)%p + rtof * xx * frt_kg * & fertdb(ifrt)%forgp soil1(j)%hsta(l)%p = soil1(j)%hsta(l)%p + (1. - rtof)*xx*frt_kg * & fertdb(ifrt)%forgp end if if (bsn_cc%cswat == 1) then soil1(j)%man(l)%c = soil1(j)%man(l)%c + xx * frt_kg * & fertdb(ifrt)%forgn * 10. soil1(j)%man(l)%n = soil1(j)%man(l)%n + xx * frt_kg * & fertdb(ifrt)%forgn soil1(j)%man(l)%p = soil1(j)%man(l)%p + xx * frt_kg * & fertdb(ifrt)%forgp end if !!By Zhang for C/N cycling !!=========================== if (bsn_cc%cswat == 2) then soil1(j)%tot(l)%p = soil1(j)%tot(l)%p + rtof * xx * & frt_kg * fertdb(ifrt)%forgp soil1(j)%hsta(l)%p = soil1(j)%hsta(l)%p + (1. - rtof) * xx * & frt_kg * fertdb(ifrt)%forgp !!Allocate organic fertilizer to Slow (SWAT_active) N pool; soil1(j)%hact(l)%n = soil1(j)%hact(l)%n + (1. - rtof) * xx * & frt_kg * fertdb(ifrt)%forgn !orgc_f is the fraction of organic carbon in fertilizer !for most fertilziers this value is set to 0. orgc_f = 0.0 !X1 is fertlizer applied to layer (kg/ha) !xx is fraction of fertilizer applied to layer X1 = xx * frt_kg !X8: organic carbon applied (kg C/ha) X8 = X1 * orgc_f !RLN is calculated as a function of C:N ration in fertilizer RLN = .175 *(orgc_f)/(fertdb(ifrt)%fminn + fertdb(ifrt)%forgn & + 1.e-5) !X10 is the fraction of carbon in fertilizer that is allocated to metabolic litter C pool X10 = .85-.018*RLN if (X10<0.01) then X10 = 0.01 else if (X10 > .7) then X10 = .7 end if end if !XXX is the amount of organic carbon allocated to metabolic litter C pool XXX = X8 * X10 soil1(j)%meta(l)%c = soil1(j)%meta(l)%c + XXX !YY is the amount of fertilizer (including C and N) allocated into metabolic litter SOM pool YY = X1 * X10 soil1(j)%meta(l)%m = soil1(j)%meta(l)%m + YY !ZZ is amount of organic N allocated to metabolic litter N pool ZZ = X1 *rtof * fertdb(ifrt)%forgn * X10 soil1(j)%meta(l)%n = soil1(j)%meta(l)%n + ZZ !!remaining organic N is llocated to structural litter N pool soil1(j)%str(l)%n = soil1(j)%str(l)%n + X1 * fertdb(ifrt)%forgn - ZZ !XZ is the amount of organic carbon allocated to structural litter C pool XZ = X1 *orgc_f-XXX soil1(j)%str(l)%c = soil1(j)%str(l)%c + XZ !assuming lignin C fraction of organic carbon to be 0.175; updating lignin amount in strucutral litter pool soil1(j)%lig(l)%c = soil1(j)%lig(l)%c + XZ * .175 !non-lignin part of the structural litter C is also updated; soil1(j)%lig(l)%n = soil1(j)%lig(l)%n + XZ * (1.-.175) !YZ is the amount of fertilizer (including C and N) allocated into strucutre litter SOM pool YZ = X1 - YY soil1(j)%str(l)%m = soil1(j)%str(l)%m + YZ !assuming lignin fraction of the organic fertilizer allocated into structure litter SOM pool to be 0.175; !update lignin weight in structural litter. soil1(j)%lig(l)%m = soil1(j)%lig(l)%m + YZ*.175 soil1(j)%tot(l)%n = soil1(j)%meta(l)%n + soil1(j)%str(l)%n !end if end if !!By Zhang for C/N cycling !!=========================== soil1(j)%mn(l)%nh4 = soil1(j)%mn(l)%nh4 + xx * frt_kg * & fertdb(ifrt)%fnh3n * fertdb(ifrt)%fminn soil1(j)%mp(l)%lab = soil1(j)%mp(l)%lab + xx * frt_kg * & fertdb(ifrt)%fminp end do !! summary calculations fertno3 = frt_kg * fertdb(ifrt)%fminn * (1. - fertdb(ifrt)%fnh3n) fertnh3 = frt_kg * (fertdb(ifrt)%fminn * fertdb(ifrt)%fnh3n) fertorgn = frt_kg * fertdb(ifrt)%forgn fertsolp = frt_kg * fertdb(ifrt)%fminp fertorgp = frt_kg * fertdb(ifrt)%forgp fertn = fertn + frt_kg * (fertdb(ifrt)%fminn + fertdb(ifrt)%forgn) fertp = fertp + frt_kg * (fertdb(ifrt)%fminp + fertdb(ifrt)%forgp) return end subroutine pl_fert