c     file: chumus.inc

c     This file contains the declaration of the common block of variables
c     related to N&P transformations from humus and fresh o.m.(residue)

c     Parameter include files:  p1werm.inc

c     + + + VARIABLE DECLARATIONS + + +
      real rsd,rsdi,rc,fon,fop,wn,wp,wim,wip,cmn,hum,rmnr,hmn,wmp,rtn,
     1 wmn,yc,twn,twmn,tap,tno3,shm,smr,sim,sdn,smp,sip,tsfn,trmn,trmp,
     2 thmn,thmp,trsd,tfon,tfop,tmp,top,tp

      common / humus /
     r                cmn,
     r                fon(mnsz),
     r                fop(mnsz),
     r                hmn,
     r                hum(mnsz),
     r                rc,
     r                rsd(mnsz),
     r                rsdi(mnsz),
     r                rmnr,
     r                rtn(mnsz),
     r                shm,
     r                smr,
     r                sim,
     r                sdn,
     r                smp,
     r                sip,
     r                tap,
     r                tno3,
     r                tsfn,
     r                trmn,
     r                trmp,
     r                thmn,
     r                thmp,
     r                trsd,
     r                tfon,
     r                tfop,
     r                tmp,
     r                top,
     r                tp,
     r                twn,
     r                twmn,
     r                wim,
     r                wip,
     r                wmn(mnsz),
     r                wmp,
     r                wn(mnsz),
     r                wp(mnsz),
     r                yc

c    rsdi,rc, are new variables not included in EPIC1910.
c
c     + + + VARIABLE DEFINITIONS + + +
c     cmn - ???
c     fon - amount of N in residue (kg/ha)
c     fop - amount of P in residue (kg/ha)
c     hmn - amount of N mineralized from active N pool (kg/ha/d)
c     hmp - amount of P mineralized from active P pool (kg/ha/d)
c     hum - amount of humus (t/ha)
c     rc - residue composition factor (0.8, or 0.05, or 0.0095)
c     rmnr - net mineralized n from all sources of o.m. (kg/ha)
c     rsd - current amount of residue (t/ha) in a layer
c     rsdi - initial amount of residue in a layer (t/ha)
c     rtn - active pool fraction
c     sdn - sum of denitrified N (kg/ha)
c     shm - sum of mineralized N from humus (kg/ha)
c     sim - sum of immobilized N (kg/ha)
c     sip - sum of immobilized P (kg/ha)
c     smp - sum of mineralized P from humus and fresh residue (kg/ha)
c     smr - sum of mineralized N from humus & fresh residue (kg/ha)
c     tap - total labile P (kg/ha)
c     tfon - total amount of N from fresh organic matter (kg/ha)
c     tfop - total amount of P from fresh organic matter (kg/ha)
c     tmp - total active mineral P from all layers (kg/ha)
c     top - total stable mineral P from all layers (kg/ha)
c     tp - total P from all humus (kg/ha)
c     tno3 - total no3_n (kg/ha)
c     trmn - total mineralized N from fresh residue (kg/ha)
c     trmp - total mineralized N from fresh residue (kg/ha)
c     thmn - total mineralized N from humus (kg/ha)
c     trmp - total mineralized P from humus (kg/ha)
c     trsd - sum of residue of all layers (t/ha)
c     tsfn - sum of N leached from all layers (kg/ha)
c     twmn - total organic N from active humus pool (kg/ha)
c     twn - total organic N from humus (kg/ha)
c     wim - immobilized n (kg/ha)
c     wip - immobilized p 9kg/ha)
c     wmn - active humus n pool (kg/ha)
c     wmp - active humus p pool (kg/ha)
c     wn - organic N concentration of humus (g/t)
c     wp - organic P concentration of humus (g/t)
c     yc - period of cultivation before simualtion starts (yr)