transput variables; std(:) : standing dead (kg ha-1) (not used) stdl(:) : mass of lignin in standing dead (kg ha-1) (not used) stdn(:) : mass of n in standing dead (dead plants + sorbed from soil; kg ha-1) (not used) stdnel(:) : standing dead n after enrichment with sorbed n in a soil layer (kg ha-1)
============================================== local variables
mm / 1000 * 10000 m2 / ha * ton/m3 * 1000 kg/ha -> kg/ha; rock fraction is considered mineralization can occur only if temp above 0 deg
compute soil water factor - sut compute soil temperature factor - when sol_tep is larger than 35, cdg is negative? compute oxygen (ox) compute combined factor call denitrification (to use void and cdg factor)
set nitrogen carbon ratios for upper layer
if (k == 1)
set nitrogen carbon ratios for lower layers
compute residue decomp and mineralization of
fresh organic n and p
!=================================
determine the final rate of the decomposition of each carbon pool and
allocation of c and nutrients to different som pools, as well as co2 emissions from different pools
!=================================
transformation processes from passive (s3), slow (s2), metabolic (met), and non-lignin structural (str) pools to microbial pool
s3 (passive humus) to s1 (microbial)
s2 (slow humus) to s1 (microbial)
metabolic litter to s1 (microbial)
structural to s1
!=================================
transformation processes from lignin structural (str) and metabolic (met) and pools to s2 (slow humus)
str (structural litter) to s2 (slow humus) s1 (microbial biomass)to s2 (slow humus) !================================= transformation processes from lignin structural (str) and metabolic (met) and pools to s2 (slow humus)
s1 (microbial biomass) to s3 (passive humus)
s2 to s3 (passive humus)
!=================================
epic procedures (not used): calculating n supply - n demand
df1 is the supply of n during structural litter decomposition (lsnta) - demand of n to meet the transformaitons of other pools
c pools into structural litter (0 as no other pools transformed into structural litter)
df2 is the supply of n during metabolic litter decomposition (lsnta) - demand of n to meet the transformaitons of other pools
c pools into metabolic litter (0 as no other pools transformed into structural litter)
!=================================
x3 = amount of c transformed from passive, slow, metabolic, and non-lignin structural pools to microbial pool
df3 is the supply of n during structural litter decomposition (lsnta) - demand of n to meet the transformaitons of passive, slow, metabolic, and non-lignin structural
c pools into microbiomass pool
!=================================
x1 = amount of c transformed from lignin structural and metabolic pools into slow humus
df4 is the supply of n during slow humus decomposition (hsnta) - demand of n to meet the transformaitons of lignin structural and metabolic pools
c pools into slow humus
!=================================
x1 = amount of c transformed from s1 (microbial biomass) into s3 (passive humus)
df5 is the supply of n during passive humus decomposition (hpnta) - demand of n to meet the transformaitons of microbial biomass
c pools into passive humus
!=================================
df6 supply of mineral n - available mineral n = n demanded from mineral pool
!=================================
update c and n of different som pools
=========================================
nonlig was being derived from the just-decremented
lig pool (e.g. nonlig%c = lig%c - lslncta), corrupting the non-lignin pool daily
and propagating to str via the line that sums them. Corrected to use the nonlig pool itself.
set residue decomposition for printing
surface residue
subsurface and root residue
update soil respiration
===============================
soil rspc for layer k
rspc_da is accounting variable summarizing co2 emissions from all soil layers
cumulative flux accumulator for hru_cflux_stat_aa file
update other variables used in swat
==================================