subroutine nut_orgnc2 !! ~ ~ ~ PURPOSE ~ ~ ~ !! this subroutine calculates the amount of organic nitrogen removed in !! surface runoff - when using CSWAT==2 it !! ~ ~ ~ INCOMING VARIABLES ~ ~ ~ !! name |units |definition !! ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ !! enratio |none |enrichment ratio calculated for day in HRU !! erorgn(:) |none |organic N enrichment ratio, if left blank !! |the model will calculate for every event !! ihru |none |HRU number !! sedc_d(:) |kg C/ha |amount of C lost with sediment !! !! !! !! |pools !! ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ !! ~ ~ ~ ~ ~ ~ END SPECIFICATIONS ~ ~ ~ ~ ~ ~ use hru_module, only : enratio, hru, ihru, sedorgn, sedyld, surfq use soil_module use organic_mineral_mass_module use carbon_module implicit none integer :: j = 0 !none |HRU number real :: xx = 0. !kg N/ha |amount of organic N in first soil layer real :: wt1 = 0. !none |conversion factor (mg/kg => kg/ha) real :: er = 0. !none |enrichment ratio real :: conc = 0. ! |concentration of organic N in soil real :: sol_mass = 0. ! | real :: QBC = 0. ! |c loss with runoff or lateral flow real :: VBC = 0. ! |c los with vertical flow real :: YBC = 0. ! |BMC LOSS WITH SEDIMENT real :: YOC = 0. ! |Organic C loss with sediment real :: YW = 0. ! |YW = WIND EROSION (T/HA) real :: TOT = 0. ! |Total organic carbon in layer 1 real :: YEW = 0. !frac |fraction of soil erosion of total soil mass real :: X1 = 0. ! | real :: PRMT_21 = 0. ! |KOC FOR CARBON LOSS IN WATER AND SEDIMENT(500._1500.) KD = KOC * C real :: PRMT_44 = 0. ! |RATIO OF SOLUBLE C CONCENTRATION IN RUNOFF TO PERCOLATE(0.1_1.) real :: DK = 0. ! | real :: V = 0. ! | real :: X3 = 0. ! | real :: CO = 0. ! | real :: CS = 0. ! | real :: perc_clyr = 0. ! | real :: latc_clyr = 0. ! | integer :: k = 0 !none |counter real :: xx1 = 0. ! | real :: sol_thick = 0. ! | real :: y1 = 0. ! | real :: c_ly1 = 0. j = ihru latc_clyr = 0. perc_clyr = 0. wt1 = 0. !! conversion factor er = 0. !! enrichment ratio !! HRU calculations c_ly1 = rsd1(j)%tot_str%n + rsd1(j)%tot_meta%n + soil1(j)%hp(1)%n + soil1(j)%hs(1)%n !wt = sol_bd(1,j) * sol_z(1,j) * 10. (tons/ha) !wt1 = wt/1000 wt1 = soil(j)%phys(1)%bd * soil(j)%phys(1)%d / 100. if (hru(j)%hyd%erorgn > .001) then er = hru(j)%hyd%erorgn else er = enratio end if conc = xx * er / wt1 !! HRU calculations sedorgn(j) = .001 * conc * sedyld(j) / hru(j)%area_ha !! update soil nitrogen pools only for HRU calculations if (xx > 1.e-6) then xx1 = (1. - sedorgn(j) / xx) !!add by zhang to update soil nitrogen pools rsd1(j)%tot_str%n = rsd1(j)%tot_str%n * xx1 rsd1(j)%tot_meta%n = rsd1(j)%tot_meta%n * xx1 soil1(j)%hp(1)%n = soil1(j)%hp(1)%n * xx1 soil1(j)%hs(1)%n = soil1(j)%hs(1)%n * xx1 !sol_BMN(1,j) = sol_BMN(1,j) * xx1 end if !return !Calculate runoff and leached C&N from micro-biomass latc_clyr = 0. sol_mass = 0. !kg/ha sol_mass = (soil(j)%phys(1)%d / 1000.) * 10000. * soil(j)%phys(1)%bd * 1000. * (1- soil(j)%phys(1)%rock / 100.) QBC=0. !c loss with runoff or lateral flow VBC=0. !c los with vertical flow YBC=0. !BMC LOSS WITH SEDIMENT YOC=0. !Organic C loss with sediment YW=0. !YW = WIND EROSION (T/HA) TOT = soil1(j)%hp(1)%c + soil1(j)%hs(1)%c + rsd1(j)%tot_meta%c + rsd1(j)%tot_str%c !Total organic carbon in layer 1 !YEW = MIN(er*(sedyld(j)/hru(j)%area_ha+YW/hru(j)%area_ha)/(sol_mass/1000.),.9) ! Not sure whether should consider enrichment ratio or not! YEW = MIN((sedyld(j)/hru(j)%area_ha+YW/hru(j)%area_ha)/(sol_mass/1000.),.9) !fraction of soil erosion of total soil mass X1=1.-YEW !YEW=MIN(ER*(YSD(NDRV)+YW)/WT(LD1),.9) !ER enrichment ratio !YSD water erosion !YW wind erosion YOC=YEW*TOT soil1(j)%hs(1)%c = soil1(j)%hs(1)%c * X1 soil1(j)%hp(1)%c = soil1(j)%hp(1)%c * X1 rsd1(j)%tot_str%m = rsd1(j)%tot_str%m * X1 rsd1(j)%tot_meta%m = rsd1(j)%tot_meta%m * X1 rsd1(j)%tot_lignin%m = rsd1(j)%tot_lignin%m * X1 rsd1(j)%tot_str%c = rsd1(j)%tot_str%c * X1 rsd1(j)%tot_meta%c = rsd1(j)%tot_meta%c * X1 !rsd1(j)%tot_lignin%c = rsd1(j)%tot_str%c - rsd1(j)%tot_lignin%c IF(soil1(j)%microb(1)%c > .01) THEN PRMT_21 = 0. !KOC FOR CARBON LOSS IN WATER AND SEDIMENT(500._1500.) KD = KOC * C PRMT_21 = 1000. soil1(j)%water(1)%c = rsd1(j)%tot_str%c + rsd1(j)%tot_meta%c + soil1(j)%hp(1)%c + soil1(j)%hs(1)%c + soil1(j)%microb(1)%c DK = .0001 * PRMT_21 * soil1(j)%water(1)%c !X1=PO(LD1)-S15(LD1) X1 = soil(j)%phys(1)%por*soil(j)%phys(1)%d-soil(j)%phys(1)%wpmm !mm IF (X1 <= 0.) THEN X1 = 0.01 END IF XX=X1+DK !V=QD+Y4 V = surfq(j) + soil(j)%ly(1)%prk + soil(j)%ly(1)%flat !QD surface runoff X3=0. IF(V>1.E-10)THEN X3 = soil1(j)%microb(1)%c * (1.-EXP(-V/XX)) !loss of biomass C PRMT_44 = 0. !RATIO OF SOLUBLE C CONCENTRATION IN RUNOFF TO PERCOLATE(0.1_1.) PRMT_44 = .5 CO = X3/(soil(j)%ly(1)%prk + PRMT_44 * (surfq(j) + soil(j)%ly(1)%flat)) !CS is the horizontal concentration CS = PRMT_44*CO !CO is the vertical concentration VBC = CO*(soil(j)%ly(1)%prk) soil1(j)%microb(1)%c = soil1(j)%microb(1)%c - X3 QBC = CS*(surfq(j)+soil(j)%ly(1)%flat) ! COMPUTE WBMC LOSS WITH SEDIMENT IF(YEW>0.)THEN CS = DK * soil1(j)%microb(1)%c / XX YBC = YEW * CS END IF END IF END IF soil1(j)%microb(1)%c = soil1(j)%microb(1)%c - YBC hsc_d(j)%surq_c = QBC * (surfq(j) / (surfq(j) + soil(j)%ly(1)%flat + 1.e-6)) soil(j)%ly(1)%latc = QBC*(soil(j)%ly(1)%flat/(surfq(j)+soil(j)%ly(1)%flat+1.e-6)) soil(j)%ly(1)%percc = VBC hsc_d(j)%sed_c = YOC + YBC do k = 2, soil(j)%nly if (soil(j)%ly(k)%prk > 0 .and. k == soil(j)%nly) then end if sol_thick = 0. sol_thick = soil(j)%phys(k)%d-soil(j)%phys(k-1)%d soil1(j)%water(1)%c = soil1(j)%str(k)%c + soil1(j)%meta(k)%c + soil1(j)%hp(k)%c + soil1(j)%hs(k)%c Y1 = soil1(j)%microb(k)%c + VBC VBC=0. IF(Y1>=.01)THEN V=soil(j)%ly(k)%prk + soil(j)%ly(k)%flat IF(V>0.)VBC=Y1*(1.-EXP(-V/(soil(j)%phys(k)%por*sol_thick-soil(j)%phys(k)%wpmm+.0001*PRMT_21*soil1(j)%water(1)%c))) END IF soil(j)%ly(k)%latc = VBC*(soil(j)%ly(k)%flat/(soil(j)%ly(k)%prk + soil(j)%ly(k)%flat+1.e-6)) soil(j)%ly(k)%percc = VBC-soil(j)%ly(k)%latc soil1(j)%microb(k)%c = Y1 - VBC !! calculate nitrate in percolate and lateral flow if (k == soil(j)%nly) then hsc_d(j)%perc_c = soil(j)%ly(k)%percc end if latc_clyr = latc_clyr + soil(j)%ly(k)%latc end do hsc_d(j)%latq_c = latc_clyr return end subroutine nut_orgnc2