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
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)
compute residue decomp and mineralization of
fresh organic n and p (upper two layers only)
!=================================
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 (structrual 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 ========================================= set residue decompostion 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 update other vairables used in swat ==================================