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CNP-Dev version based on MERGE-OCN revision 2567

1. Mass conservation issue: stomate_growth_fun_all.f90

The carbon being allocated to biomass pools must no be substracted before nutrient limitation of allocation is computed. This can be fixed by following:

!DSGdebug_01
! do NOT this now, do it after nutrient limitation on allocation is considered in bm_alloc_tot(ipts,j)
!    ! Update the labile carbon pool 
!    biomass(ipts,j,ilabile,icarbon) = biomass(ipts,j,ilabile,icarbon) - &
!    bm_alloc_tot(ipts,j)
!DSGdebug_01

    !! 3.10 Maintenance respiration

          ! The calculation of ::resp_maint is solely based on the demand i.e.
          ! given the biomass and the condition of the plant, how much should be
          ! respired. It is not sure that this demand can be satisfied i.e. the 
          ! calculated maintenance respiration may exceed the available carbon

          !DSGdebug_01 
          ! DEFAULT CASE: There is no deficit which must be subtracted from labile
          deficit = zero
          !DSGdebug_01
             
          IF ( bm_alloc_tot(ipts,j) - resp_maint(ipts,j) .LT. zero ) THEN

[...]

                ! Not enough carbon to pay the deficit, the individual 
                ! is going to die at the end of this day
                bm_alloc_tot(ipts,j) = bm_alloc_tot(ipts,j) + &
                     biomass(ipts,j,icarbres,icarbon) 
                biomass(ipts,j,icarbres,icarbon) = zero

                ! Truncate the maintenance respiration to the available carbon
                resp_maint(ipts,j) = bm_alloc_tot(ipts,j)
                

                !DSGdebug_01 
                ! There is no deficit which must be subtracted from labile
                deficit = zero
                !DSGdebug_01
             ENDIF

[...]

          ! Final ::resp_maint is know
          bm_alloc_tot(ipts,j) = bm_alloc_tot(ipts,j) - resp_maint(ipts,j)

          !DSGdebug_01 
          ! Subtracted the deficit from labile pool
          biomass(ipts,j,ilabile,icarbon) = biomass(ipts,j,ilabile,icarbon) - &
                                            (resp_maint(ipts,j) + deficit)
          !DSGdebug_01

          !! 3.11 Growth respiration
          !  Calculate total growth respiration and update allocatable carbon
          !  Growth respiration is a tax on productivity, not actual allocation
          !  Total growth respiration has be calculated before the allocation 
          !  takes place because the allocation itself is not linear. After 
          !  the allocation has been calculated, growth respiration can be 
          !  calculated for each biomass component separatly. The unit of
          !  resp_growth is gC m-2 dt-1
          resp_growth(ipts,j)  = frac_growthresp(j) * MAX(zero, bm_alloc_tot(ipts,j))
          bm_alloc_tot(ipts,j) = bm_alloc_tot(ipts,j) - resp_growth(ipts,j)

          !DSGdebug_01 
          biomass(ipts,j,ilabile,icarbon) = biomass(ipts,j,ilabile,icarbon) - &
                                            resp_growth(ipts,j)
          !DSGdebug_01

[...]

    !=======================================================
    ! Block from OCN but I did not find it in DOFOCO ???
    !
    ! 5.1 retrieve allocated biomass from labile pool (nitrogen, or new allocation)
    !

    !DSGdebug_01
    ! This is the right spot to remove bm_alloc_tot:
    biomass(:,:,ilabile,icarbon)   = biomass(:,:,ilabile,icarbon)   - bm_alloc_tot(:,:)
    !DSGdebug_01
    biomass(:,:,ilabile,initrogen) = biomass(:,:,ilabile,initrogen) - n_alloc_tot(:,:)

2. Mass conservation issue: stomate_phenology.f90

The nutrient demand must be calculated AFTER the final Cl_init and Cr_init are known. This can be fixed by:

                ! The biomass available to use is set to be the minimum of the biomass of 
                ! the labile pool (if carbon not taken from the atmosphere), and 
                ! the wanted biomass.
                bm_use(i) = MIN( biomass(i,j,ilabile,icarbon) + biomass(i,j,icarbres,icarbon), &
                     bm_wanted(i) )

     !DSGdebug_02           ! the nutrients need to support the biomass: 
     !DSGdebug_02           bm_wanted_n(i) = (Cl_init +  Cr_init*fcn_root(j))/cn_leaf_prescribed(j)

[...]

                ! In case nitrogen or phosphorus is not sufficiently available
                ! downregulate new leaf biomass to respect leaf stoichiometry;
                ! DSG: this violates the ratio used to calculate the
                ! leave-root-sapwood relationships: is this OK?

     !DSGdebug_02: moved after Cl_init and Cr_init are updated 
                ! the nutrients need to support the biomass: 
                bm_wanted_n(i) = (Cl_init +  Cr_init*fcn_root(j))/cn_leaf_prescribed(j)
     !DSGdebug_02