# 6.11. jules_soil_ecosse.nml¶

This file sets options and parameters for the ECOSSE model of soil biogeochemistry. It is used only if the ECOSSE model is chosen (soil_bgc_model = 3).

Warning

The ECOSSE model in JULES is still in development and is not fully functional in this version. The code is included to allow further development. Users should not try to use ECOSSE.

## 6.11.1. JULES_SOIL_ECOSSE namelist members¶

JULES_SOIL_ECOSSE::l_soil_n
Type: logical T

Switch to include soil nitrogen in ECOSSE.

TRUE
Model soil carbon and nitrogen.
FALSE
Model only soil carbon.
JULES_SOIL_ECOSSE::l_match_layers
Type: logical T

Switch to match ECOSSE soil C and N layers to those for soil moisture.

TRUE
Use the same layering as for soil moisture. The number of soil carbon layers will equal sm_levels, with layer thicknesses given by dzsoil_io.
FALSE
The number of layers will be specified by dim_cslayer and the thicknesses by dz_soilc_io.
JULES_SOIL_ECOSSE::dim_cslayer
Type: integer >= 1 None

The number of ECOSSE soil carbon layers. Not used if l_match_layers = TRUE.

JULES_SOIL_ECOSSE::dz_soilc_io
Type: real(dim_cslayer) > 0 None

Thicknesses of the ECOSSE soil carbon layers (m). Not used if l_match_layers = TRUE. In most cases the total depth must equal that of the soil moisture layers (see dzsoil_io). The exception is the case of a single layer, bulk model (dim_cslayer = 1), for which dz_soilc(1) is interpreted as the representative or averaging depth for the bulk layer (e.g. the temperature of the bulk model is taken as the average over this depth).

JULES_SOIL_ECOSSE::dt_soilc
Type: REAL >= timestep_len timestep_len

The timestep length for ECOSSE (seconds). The main JULES timestep length timestep_len must be a multiple of this timestep length, so that ECOSSE is called on JULES timesteps. The TRIFFID timestep length triffid_period (converted to seconds) must also be a multiple of the ECOSSE timestep length.

JULES_SOIL_ECOSSE::l_driver_ave
Type: logical T

Switch controlling the averaging of the physical driving variables that are input to ECOSSE (e.g. soil temperature).

TRUE
Average the driving variables over the ECOSSE timestep length.
FALSE
Use instantaneous values of the driving variables at the time when ECOSSE is called.
JULES_SOIL_ECOSSE::plant_input_profile
Type: INTEGER 1 or 2 1

Switch for the vertical distribution of litterfall inputs of C and N to the soil.

Possible values are:

1. Fraction pi_sfc_frac of inputs are distributed uniformly in a surface layer of depth pi_sfc_depth, the remainder are distributed according to the distribution of roots.
2. Inputs decrease exponentially with depth with decay constant tau_lit.
JULES_SOIL_ECOSSE::pi_sfc_frac
Type: REAL 0.3

Fraction of plant litterfall that is added to the surface soil layer of depth pi_sfc_depth. Only used if plant_input_profile = 1.

JULES_SOIL_ECOSSE::pi_sfc_depth
Type: REAL 0.1

Depth of soil over which fraction pi_sfc_frac of plant litterfall is added (m). Only used if plant_input_profile = 1.

JULES_SOIL_ECOSSE::temp_modifier
Type: INTEGER 1 or 2 2

Switch for the form of the temperature rate modifier for decomposition.

1. Use a Q10 approach.
2. Use the RothC form of the modifier.
JULES_SOIL_ECOSSE::water_modifier
type: INTEGER 1 or 2 2

Switch for the form of the water rate modifier for decomposition and nitrification.

1. Use the JULES form of the modifier.
2. Use the RothC form of the modifier.
JULES_SOIL_ECOSSE::decomp_rate
Type: REAL(4) 3.22e-7, 9.65e-9, 2.12e-8, 6.43e-10

Rate constant for decomposition of each soil carbon pool (s-1).

Note that these default values are also those for use with the RothC model (kaps_roth).

JULES_SOIL_ECOSSE::decomp_ph_rate_min
Type: REAL 0.2

Minimum allowed value of pH rate modifier for decomposition.

JULES_SOIL_ECOSSE::decomp_ph_min
Type: REAL decomp_ph_min <= decomp_ph_max 1.0

Soil pH below which rate of decomposition is minimum.

JULES_SOIL_ECOSSE::decomp_ph_max
Type: REAL decomp_ph_max >= decomp_ph_min 4.5

Soil pH above which rate of decomposition is maximum.

JULES_SOIL_ECOSSE::decomp_temp_coeff_rothc
Type: REAL(3) 47.9, 106.0, 18.3

Constants in the RothC from of the decomposition temperature modifier (temp_modifier = 2).

Note that these default values are also those harwired in the code for use with the RothC model (soil_bgc_model = 2, l_q10 = F ).

JULES_SOIL_ECOSSE::decomp_wrate_min_rothc
Type: REAL 0.2

Minimum allowed value of the water rate modifier for decomposition when the RothC form is used (water_modifier = 2).

JULES_SOIL_ECOSSE::decomp_wrate_min_jules
Type: REAL 0.2

Minimum allowed value of the water rate modifier for decomposition when the JULES form is used (water_modifier = 1).

Note that this default value is also that harwired in the code for use with the RothC model (soil_bgc_model = 2).

Parameters for ECOSSE that are only used if soil N is included (l_soil_n = TRUE).

JULES_SOIL_ECOSSE::l_decomp_slow
Type: logical T

Switch controlling how lack of nitrogen affects soil decomposition.

TRUE
Reduce the decomposition rate.
FALSE
Reduce the efficiency of decomposition, so that decomposition results in increased production of CO2 and decreased production of further soil C. This is the approach used in the standalone version of ECOSSE.
JULES_SOIL_ECOSSE::depo_nit_frac
Type: REAL 0 <= depo_nit_frac <= 1 1.0

The fraction of nitrogen deposition that is aded to the soil nitrate pool. The complement is aded to the ammonium pool.

JULES_SOIL_ECOSSE::bacteria_min_frac
Type: REAL 0 <= bacteria_min_frac <= 1 0.2

The minimum fraction of the decomposer community that are bacteria.

JULES_SOIL_ECOSSE::bacteria_max_frac
Type: REAL bacteria_min_frac <= bacteria_max_frac <= 1 0.5

The maximum fraction of the decomposer community that are bacteria.

JULES_SOIL_ECOSSE::bacteria_min_frac_pH
Type: REAL 4.0

The soil pH at or below which the fraction of bacteria is at a minimum.

JULES_SOIL_ECOSSE::bacteria_max_frac_pH
Type: REAL bacteria_min_frac_pH <= bacteria_max_frac_pH 5.5

The soil pH at or above which the fraction of bacteria is at a maximum.

JULES_SOIL_ECOSSE::cn_bacteria
Type: REAL 5.5

The C:N ratio of soil bacteria.

JULES_SOIL_ECOSSE::cn_fungi
Type: REAL 5.5

The C:N ratio of soil fungi.

JULES_SOIL_ECOSSE::depth_nitrif
Type: REAL 0.25

Greatest depth at which nitrification and denitrification are allowed (m).

JULES_SOIL_ECOSSE::nitrif_rate
Type: REAL 9.921e-7

Rate constant for nitrification (s-1).

JULES_SOIL_ECOSSE::nitrif_wrate_min
Type: REAL 0.6

Minimum allowed value of the water rate modifier for nitrification when RothC form is used. Only used if water_modifier = 2.).

JULES_SOIL_ECOSSE::nitrif_max_factor
Type: REAL 0.1

Shape factor in rate modifier for nitrification (kg m-3).

JULES_SOIL_ECOSSE::nitrif_frac_n2o_fc
Type: REAL 0 <= nitrif_frac_n2o_fc <= 1 0.02

Fraction of nitrification lost as N2O by partial nitrification at field capacity.

JULES_SOIL_ECOSSE::nitrif_frac_gas
Type: REAL 0 <= nitrif_frac_gas <= 1 0.02

Fraction of nitrification lost as gas through full nitrification.

JULES_SOIL_ECOSSE::nitrif_frac_no
Type: REAL 0 <= nitrif_frac_no <= 1 0.4

Fraction of nitrification gas loss through full nitrification that is NO.

JULES_SOIL_ECOSSE::denit50
Type: REAL 0.033

Amount of nitrate at which denitrification rate is 50% of the potential rate (kg m-3).

JULES_SOIL_ECOSSE::denit_bio_factor
Type: REAL 0.005

Factor in denitrification calculation to convert flux of CO2 into a representation of biological activity (m2 kg-1).

JULES_SOIL_ECOSSE::denit_frac_n2_fc
Type: REAL 0 <= denit_frac_n2_fc <= 1 0.55

Proportion of denitrified N that becomes N2 when soil moisture is at field capacity.

JULES_SOIL_ECOSSE::denit_nitrate_equal
Type: REAL 0.4

Amount of N in soil nitrate at which denitrified N is released as equal amounts of N2 and N2O (kg m:sup:-3).

JULES_SOIL_ECOSSE::denit_water_coeff
Type: REAL(3) 0.62, 0.38, 1.74

Constants describing water modifier for denitrification.

JULES_SOIL_ECOSSE::amm_leach_min
Type: REAL 0.02

Minimum allowed amount of N in soil ammonium after leaching (kg m-3).

JULES_SOIL_ECOSSE::n_inorg_max_conc
Type: REAL -1.0

Maximum-allowed concentration of inorganic N in a layer (kg m-3). A value less than zero means no maximum concentration is imposed.